Helical products, including Helical machined springs, Helical couplings, and U-joints offer solutions to many unique engineering problems.
Learn more about how Helical products have solved unique challenges in this collection. of case studies.

Aerospace Automotive Industrial Medical

Military Energy Semiconductor Other

To navigate to a specific market section, click on the coordinating button.

CHALLENGE

The customer was producing a hand operated elevator. The elevator is used to load missiles and/or bombs onto the underside of aircraft wings. When the elevator is in position) it is released and must remain in position until the munitions are secured to the racks. The customer was unable to find a wire wrap wound clutch to function properly. After several failed attempts to make the clutch themselves, they found us. We were able to meet all their requirements.

SOLUTION

The highest stress point in a wire wrap wound clutch is where the ends are turned ninety degrees to the normal wrap of the wire. When the HELI-CAL Flexure is "machined" we not only don't bend the coil ninety degrees, but we are able to leave additional material in the radius of the stem which increases the strength and reduces the stress level even more. Helical was again able to solve a customer's application with a reliable HELi-CAL Flexure that also saved them production time in assembling their complete product.

ANSWER

HELI-CAL Flexure Precision "Machined" Spring/Clutch # 2165

CHALLENGE

Aerospace rockets, satellites, vehicles and living vessels have the need to control small amounts of fluids and gasses. To this end, small control valves are needed to proportion the fluids and gasses as needed for propulsion and environmental activities.

Small valves that are fashioned specifically for each application is the norm. Such valves require specific springs with demanding features.

SOLUTION

By using the HELI-CAL® Flexure in a single or double start configuration and adding attachment features, aerospace valves have been configured to meet the performance and minimum weight constraints imposed.

ANSWER

HELI-CAL Flexured Machined Springs: 2400, 2401, 2416 , 2419, 2427, 2428, 2446, 2454, 2465, 2492, 2506, 2507, 2509, 2511, 2512, 2566, 2586, 2552, 2586, 2616, 2674, 2675, 2676, 2677

CHALLENGE

A response to low efficiency pumping systems involves the use spring-mass resonant arrangements that operate at the resonant frequency of a piston mass connected to a compression/extension spring.

The first pumps used wire wound springs but were hindered by coil clashing creating noise, debris and low efficiency.

SOLUTION

By using the HELI-CAL® Flexure in a double start configuration and adding attachment features, the problem resolved quickly. The Double Start Flexure allowed motion of the piston to be very straight, thus not needing guidance by energy robbing piston wall contact. The constant width slots typical in a machined spring prevent the coil contact typical in closed and ground wire wound springs. Operation of a resonant pump using Double Start Machined Springs is silent and efficient.

ANSWER

HELI-CAL Flexured Machined Spring: DS2673

CHALLENGE

A NASA-funded Jet Propulsion laboratory's assignment was to develop a Martian data-gathering
vehicle. The project successfully launched on December 4, 1996, at 10:58 p.m. PST. The project name is ''Mars Pathfinder," and one aspect of it is the Rover Sojourner APXS (Alpha, Proton, X-ray, Spectrometer) deployment system. The Rover Sojourner is a small radio-controlled cart that can roam around the surface of Mars, back up against a rock, allow the APXS transducer head to align to the rock, radiate the rock, gather the reflected radiation and determine the composition of the rock. This application requires conformance to the Martian surface by the transducer.

SOLUTION

The most common way to accomplish a compliance motion is by using a gimbaled, spherical joint. Such a device is typical but requires clean, sliding surfaces and is relatively heavy. One of the customer's development engineers decided to try something different: a totally elastic device. The plan was to use three machined springs situated at the three corners of an equilateral triangle. The springs would be subject dominantly to lateral bending, but small compression deflections are also possible. The spring design is made from 15-SPH CRES for optimized weight, with threaded end attachments. The small .063-inch diameter holes are for a hook spanner to tighten the threads. The total weight is 6 grams.

ANSWER

HELI-CAL Flexure Precision "Machined" Spring# 2421

CHALLENGE

On the common twin-engine turbo-prop commuter aircraft, a fuel control system utilizing a ground end wire wound spring was used. The spring and surrounding assembly required servicing after 50 hours of usage. The airline industry demanded an assembly with a longer service life.

SOLUTION

The alternative design developed by Helical's Application Group basically was the same envelope (OD/length). The ID was a little smaller and some integrated attachments were added. It was found that the existing wound spring had its first mode frequency excited at normal engine running speeds, this action was a side-to-side motion. When excited at this mode, the spring would swing back and forth and wear out a diaphragm surrounding the spring. After extensive analysis at Helical, an alternative was found that exhibited its first-mode excitation frequencies outside normal engine speeds. With this configuration, service intervals have been extended by 10 times and tests suggest that 100 times may be possible. This explains why the customer was willing to purchase a machined spring over a wire wound spring even with a price increase exceeding 4 times.

ANSWER

HELi-CAL Flexure Precision "Machined" Spring# 2345

CHALLENGE

A manufacturer of linear and rotary actuators came to Hehcal in 1975 looking for a spring element to project the puck of a disc brake. Their actuators are driven by electric motors which, when turned off, need to stop immediately. Minimal over-run was desired. To control over-run, an electric disc brake was adopted which is not common in the industry. Somewhat like truck air brakes, the actuator brake is always on and is released by an armature drawing the puck away from the disc. The spring had to be made of electron beam weldable material (the spring would be welded in place), have a specific rate and force, be lightweight, and distribute forces uniformly across the spring ends.

SOLUTION

Helical's machined, square-ended springs were a perfect fit. We decided upon a thin-walled, 1 1/2 coil, single start spring from 17-4pH corrosion-resistant steel (CRES).

This solution worked so well that through the years 37 additional single and double start springs have been added. The ability to change size and performance, yet retain the basic configuration, has made this application one that continues to grow.

ANSWER

HELI-CAL Flexure Precision "Machined" Spring# 236 and 37 others.

CHALLENGE

This application came from the aircraft industry. The customer needed an answer to a short cycle life. The tang end bent on a wire wound clutch was unable to withstand the high forces involved causing the unit to fail when the tang broke off. Helical was calJe<l, "Can you help?"

SOLUTION

The HELl-CALov Flexure is a machined part, with no bending of material, therefore, no additional stresses are put into the end product. There were two methods of reducing stress levels; ( 1) producing the tang with more material in the tang and (2) radius of the point where the tang connects to the end coil.

ANSWER

HELl-CAL Flexured Machined Spring Clutch# R2 l91

CHALLENGE

The customer was using rigid-mounted circuit boards which were cracking from extreme vibrations. A device to keep electrical contact and a method to absorb the vibration was needed. The boards were in a fluid environment allowing for damping to the system. The spring must be nexible in bending and axial movements. Can Helical solve the situation?

SOLUTION

During discussions with the customer, different attachment ideas and materials were suggested. Brass or aluminum were the customer's first choices. The tightening torque for securing a nut was to be 12 lb/in. After sketches were sent back and forth, samples were sent for testing and evaluation. This particular application called for a material not normally used by Helical-copper impregnated with aluminum (Glidcop, AL60). After a long test and evaluation program, the proposed spring was approved and production started.

ANSWER

HELl-CAL® Flexure Machined Spring #2370

CHALLENGE

While providing a product orientation to a company's group of design engineers, a question was asked, "Would Helical be able to retrofit a spring now being used as a buffer spring in a fuel control system? The unit should compress and extend .100 of an inch."

SOLUTION

After a preliminary discussion between the customer and our application engineer, a sketch of our concept was forwarded to be reviewed. A few minor changes were needed. Material was a concern to be resolved before the final configuration was proposed. Two samples were sent to verify the installation and spring rate. There were a considerable number of conversations between the engineers regarding which material to use - l 7-7 PH, Inconel, 17-4 PH, 15-5 PH. Material is an important aspect as it may affect the performance of the machine spring. Complete life testing was done by our customer as well as their customer. Solving this project led to several other spring applications of the same configurations but with varying spring rates.

ANSWER

HELl-CAL® Flexure Machined Spring # 2329

CHALLENGE

Aerospace rockets, satellites, vehicles, and living vessels have the need to control small amounts of fluids and gasses. To this end, small control valves are needed to proportion the fluids and gasses as needed for propulsion and environmental activities.

Small valves that are fashioned specifically for each application are the norm. Such valves require specific springs with demanding features.

SOLUTION

By using the HELI-CAL® Flexure in a single or double start configuration and adding attachment features, aerospace valves have been configured to meet the performance and minimum weight constraints imposed.

ANSWER

HELI-CAL Flexured Machined Springs: 2400, 2401, 2416, 2419, 2427, 2428, 2446, 2454, 2465, 2492, 2506, 2507, 2509, 2511, 2512, 2566, 2586, 2552, 2586, 2616, 2674, 2675, 2676, 2677

CHALLENGE

A response to low-efficiency pumping systems involves the use of spring-mass resonant arrangements that operate at the resonant frequency of a piston mass connected to a compression/extension spring.

The first pumps used wire wound springs but were hindered by coil clashing creating noise, debris, and low efficiency.

SOLUTION

By using the HELI-CAL® Flexure in a double start configuration and adding attachment features, the problem was resolved quickly. The Double Start Flexure allowed the motion of the piston to be very straight, thus not needing guidance by energy-robbing piston wall contact. The constant width slots typical in a machined spring prevent the coil contact typical in closed and ground wire wound springs. The operation of a resonant pump using double-start machined springs is silent and efficient.

ANSWER

HELI-CAL Flexured Machined Spring: DS2673

CHALLENGE

Aerospace rockets, satellites, vehicles, and living vessels have the need to control small amounts of fluids and gasses. To this end, control valves are needed to proportion the fluids and gasses as needed for propulsion and environmental activities.

Valve systems are created as needed, and it is the norm that valves require specific springs with demanding features and performance.

SOLUTION

By using the HELI-CAL® Flexure in a Triple Start, extension spring configuration with specific attachment features, this aerospace valve spring has been configured to be welded into place and meet the performance requirements of axial stiffness, lateral stiffness, modal response, and imposed weight constraints.

ANSWER

HELI-CAL Flexured Machined Spring: TS20112

CHALLENGE

A manufacturer of racing engines needed to connect the individual throttle valves together on an IndyCar race engine. The throttle valves regulate the flow of air into each combustion chamber on the fuel-injected engine. This is then connected to the throttle linkage, which is controlled by the driver's foot pedal.

The flexible coupling is used to compensate for normal misalignments caused by manufacturing tolerances and distortion of the manifold containing all the throttle bores. Another concern was the extremely high vibration levels from engines running at 13,000 RPM and the forces caused by the high engine torque.

SOLUTION

The most difficult problem the flexible coupling had to overcome was the vibrational forces and twisting caused by the high torque of the engine, in addition to the normal tolerances and misalignments in the manufacturing of the manifolds. These units have been well-tested and proven to accomplish everything the customer wanted in a flexible shaft coupling. It h.as been very successful in actual racing.

ANSWER

HELi-CAL Flexure Flexible Shaft Couplings II 6313 and # 6607.

CHALLENGE

It all started in 1973. A manufacturer of conveyor systems contacted Helical concerning a flex_ible coupling to compensate for misalignment between a side mounted motor and rollers. Torque capacity and reliability was impo11ant.

SOLUTION

A sample of a new series of Helical motor couplings was sent to the customer for test and eval­uation and to verify the flexure coupling concept within their system. It worked fine, however they required a hex on their drive shaft to maintain a positive drive. To assure reliability in the drive system the customer asked that the coupling be provided with a hex at one end and a key­way al the other. ln twenty-five years there have been nine different variations of this coupling. The primary differences were in the type of attachments, the HELl-CAL® Flexure basically remained Lbe same. The customer is still purchasing the flexible shaft coupling.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 3370 and 6 other specials, plus 2 standards

CHALLENGE

This wrap spring clutch is a locking mechanism for a handler/manipulator in a semiconductor test system robot. The unreliability of a multiple-piece clutch did not give the customer a feeling of security.

SOLUTION

The customer supplied us with the dimensions; i.e. I.D., O.D., size, and number of coils, width of wire, and direction of operation. The wire wrap spring clutch applications normally replace or retrofit an existing device. Because of the unique Helical Flexure and method of attachment, it becomes a single integrated unit, thereby reducing the number of parts to be inventoried and providing a more reliable clutch.

ANSWER

HELI-CAL Flexure Precision "Machined" Spring/Clutch# 2403

CHALLENGE

A long-term customer asked if we could add a small amount of elasticity to a line of machine tool holders that enhance the life of taps involved in CNC, metal tapping.

The new generation of CNC mills is full of capability and capacity. Machining tasks of years past gave rise to machinists who developed tricks and specialized procedures that enhanced the machining of complex items. While those skills are still valuable, the world of CNC machines has added precision, capability and precision to the world of machining. One small problem exists, however.

It is impossible for a CNC machine to perfectly follow the needed motion for rigid tapping. The motion profile is usually very close, but not perfect. As a result, tap life is shorter than optimal.

SOLUTION

By using the HELI-CAL® Flexure to compensate for the minute differences between tap geometry and the motion provided by CNC mills, tap life in rigid tapping applications has been greatly extended.

Since the company involved has the ability to manufacture the spring blanks themselves, they have called upon Helical’s Generate-Only service to just machine the Flexure. As always, Helical’s engineering staff computed the Flexure geometry to meet the customer’s needs.

ANSWER

HELI-CAL Generate-Only, Flexured Machined Springs: G1145, G1146, G1157, G1159, G1160, G1161, G1162, G1167, G1170, G1171, G1184, G1185, G1197, G1198, G1199, G1200, G1204, G1207, G1209, G1210, G1215

CHALLENGE

A rail system is used in transporting garments for apparel manufacturers, department stores, or dry cleaners. Garments are moved around the facilities on a track requiring two angular misalignments of 17 degrees horizontal and 5 degrees vertical planes. There are two systems, each using different size rails.

In the original concept, the customer manufactured three pieces, consisting of a switching mechanism, a locking device, and a shaft plus a purchased wound spring. This method did not give a smooth operation or adequate misalignments and was cumbersome to assemble into a complete package. The customer was looking for an easier method to assemble the four separate pieces, plus a cost savings.

SOLUTION

The salesman acted as a liaison between the customer's design engineer and Helical's Application Engineer. They were able to design a universal joint with special end connections into a single unit that met all of the customer's requirements and ease of final assembly. Price was also an important factor. When the customer calculated all their costs; i.e., purchasing, inventory of tubing, manufacturing, warehousing, and assembling, it was found to be cost-effective to use the HELI-CAL Flexure. This U-Joint does not rotate but allows the desired misalignments.

ANSWER

HELI-CAL Flexured U-Joint II 6814X3

CHALLENGE

A company that produces "Vibration Monitoring Instrumentation for Rotating Machines" asked us to help them devise a unit that would act similar to an encoder. They wished to incorporate an incremental counting method into this unit. The customer was using a rubber-type coupling and modifying it to use in measuring phase position and shaft speed.

SOLUTION

By using a standard WAC25 coupling as a base, the 20 cogs (18-degree steps) and the .25" wide slot for an absolute point were all combined into a homogeneous piece of material. This is another example of the versatility of integrating multiple pieces and operations into a HELT-CAL Flexw·e.

This was accomplished in a relatively short period of time, only 3 months. The coordination between the salesman, the customer's engineer, and our application engineer helped move this project along. There were four various samples provided to the customer before they decided on a final configuration.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 6835X3

CHALLENGE

The customer wished to enhance their line of leadscrew assemblies by being able to offer a flexible coupling. This flexible coupling would allow the customer to present a more complete package with their product. They envisioned using our standard flexible coupling AC075 with a 10-32 threaded bore.

SOLUTION

As you can see, it developed into a final configuration of 1.00" OD, 1.28" long, integral clamps (10-32 thread in the A2 bore, wrench flats were placed on this end as well). Also, to blend the flexible coupling into their system they had asked that it have a black anodize finish.

The development time was a mere three months from first contact to first order. This is the case that occurs many times - The customer wants a standard coupling except for "threaded bore; O.D. change; w ench flats" ... otherwise it's a standard coupling.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 6887

CHALLENGE

A customer had problems with a wire feeding unit in a stapling machine. The stapler is used to fasten magazine pages together. The unit was made up of a flexible spring coupling welded onto a shaft with a gear attached. The entire machine is made in Italy.

The customer didn't know the tolerances for any dimensions, torque or the torsional stiffness rating. A unit that is currently being used by the customer was supplied to Helical. From that, a "guesstimate" was made and Helical was able to provide a best effort paid sample.

SOLUTION

This is an illustration of being able to retrofit a part. When the end user proves it is functional, then the machine manufacturer can be contacted with the idea of Helical

fw·nishing the complete part to them. Note, there are two bearing surfaces, a gear and a HELi-CAL Flexure with a tapered bore on the A2 end. Helical's Application Engineer was able to put it all into a single piece of 17-4pH stainless steel.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 6883

CHALLENGE

In 1985 a manufacturer of sheet metal fabrication equipment was up-dating and redesigning their product. Previously they had been using our standard MC7 150 flexible coupling; however, they needed a torsionally stiffer coupling connection with the servo motor. In this redesign, they also wished to increase the functions of their system.

SOLUTION

By introducing a set of tangs at one end and a tapered bore at the opposite end, it was possible to shorten the overall coupling length by almost a half inch. In the third revision, a keyway was added plus three tapped holes and a .125" x .250" deep hole. It is not always known why certain features are made to a unit by the customer. The purpose is to enhance the HELI-CAL Flexure to the best advantage to meet the customer's requirements. This unit improved their product and has been manufactured continually since 1986.

ANSWER

HELI-CAL Flexure Flexible Coupling# D85232

CHALLENGE

An international manufacturer of large hydraulic motors had a need to count rotations and find angular position of their crankshaft. These hydraulic motors are used in many industries requiring large output motors: pulp and paper production, chemicals, material handling, mining, food processing, and others.

The hydraulic motors provided power in various applications where electric motors or internal combustion engines would not be appropriate. While other types of engines or motors may ultimately be used to pressurize the hydraulic fluid in the hydraulic motors, they can be located in a remote location with hydraulic tluid lines connecting them.

SOLUTIONS

The end of the crankshaft, which is immersed in hydraulic oil, is in a sealed compartment. It already has threads in the end of it which has a plug that seals in the high pressure hydraulic fluid. By providing this company with two separate couplings, Helical was able to mechanically connect the driveshaft to an encoder mounted outside the crankcase. The coupling inside the crankcase serves several functions. It is threaded on one end with wrench flats that allow it to be tightened into the end of the crankshaft. This not only mounts the coupling to the crankshaft, but also seals the high pressw·e internal passages of the crankshaft from the crankcase. On the other side of the flexure an extension shaft riding in oil seals• protrudes outside the side motor cover. Another coupling then connects this extension shaft to the encoder. The encoder is mounted to the outside of the crankcase.

ANSWER

HELI-CAL Flexure Flexible Shaft Couplings II ASM6418 and II ACRl00

CHALLENGE

A manufacturer of xenon flash lamps found the lamps increased in length from the heat generated when the lamp was on. The company wanted the electrical connection to the lamp to have these features:

1. Compliant electrical connection to the lamp.
2. Compression compensation for thermal growth.
3. Threaded stud for electrical supply.
4. Corrosion resistant since water will be flowing over the connection.

SOLUTION

The final machined spring design should be considered a premier example of Value
Engineering. 'rhis concept encourages that a single item performs as many primary and secondary functions as possible; the more the better. The electrical connection for the lamp was accomplished by the slotted end receiver. The HELi-CAL Flexure was sized to
provide the desired thermal growth compensation and not become a limiting resistive element since it is in the electrical current path. The threaded end addressed the electrical attachment requirement, and the whole item was manufactured from corrosion-resistant 303 Stainless Steel.

ANSWER

HELI-CAL Flexure Precision "Machined" Spring# 228

CHALLENGE

In the use of industrial CO2 and Nd YAG lasers, there was a need to redirect the laser beam efficiently and effectively. When laser beams are redirected by mirrored surfaces, there is a 1 % - 2% loss of energy to the mirror. This energy becomes heat that needs to be quickly dissipated. Since the lasers are of high wattage industrial machining type, the heat buildup required serious attention. The challenge was how to hold the mirror and how to dissipate the retained heat energy.

SOLUTION

When Helical was consulted, it was apparent that both of these functions could be accomplished within one machined compression spring. It was decided to hold the mirror against a locating and retaining bezel with a spring element and provide a heat sink on the back of the mirror. High strength aluminum was selected because of its heat transfer characteristics and low cost. The first spring was designed and shipped in 1982 and since then 7 different variations have evolved with the last in 1994. This application is a good example of how machined springs can contribute to Value Engineering (the science of creating machined elements that perform multiple functions) and how a well-conceived usage for a machined spring product can continue to be viable over several years.

ANSWER

HELi-CAL Flexure Precision "Machined" Spring II 296

CHALLENGE

A Helical Representative visited a customer to assist in solving a problem of connecting a motor to an end effector on a light-duty industrial robot. The robots are used for silicon wafer handling in computer chip manufacturing. Standard Helical couplings were initially sampled to the customer for test and evaluation.

During endurance tests, the customer sent a drawing to Helical which showed interest in the concept of incorporating the coupling and the end effector into a single unit. The end effector picks up the flat disks with vacuum suction for manipulation. Larger and heavier disks required larger end effectors. As a result, a family of special couplings was needed.

SOLUTION

On the small robot, a special coupling was designed which combined the coupling with the end effector into a single-piece unit. A HELI-CAL Flexure and shaft attachment were specially designed to meet the performance requirements of the application and minimize expense.

To keep costs down on the heavy-duty effectors, they were made separately and are part of an assembled coupling.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 6806X2 plus ASM6879X3 and ASM6880X2

CHALLENGE

A material handling equipment manufacturer had a problem transmitting rotational information from an auxiliary motor shaft to a potentiometer. The potentiometer could not be mounted to the motor case because the vibration of the motor caused problems. When the "pot" was mounted to an adjacent structure, a flexible coupling was needed to accommodate misalignment. Several different couplings were tried, however, the "pot" required very soft lateral bending to protect the shaft bearings.

SOLUTION

In order to provide for sufficient misalignment and bending softness, a coupling with several thin coils was selected. The customer indicated that they could control shaft penetrations on either end of the coupling, so there was no relief required.

Five different couplings were sampled in order to find the proper coupling specifications of flexibility, size, and price. The customer has been ordering the selected coupling at a rate of over 800 per year. This is another example of careful design resulting in a satisfied new customer, and we participated in a new production program.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling # 5639

CHALLENGE

While simple in concept, this customer needed a particular function pcitormed repeatedly by a machine tool. The operation is sensing the position of the pat1 to be machined without allowing electrical contact with it. Electrical contact was not allowed between the work piece and the sensor as it would disrupt the output signal.

SOLUTION

By inserting a dielectric bushing into one end of a special Helical coupling we were able to accomplish this electrical isolation. The sensor's probe slides into the dielectric bushing and the integral clamp is attached to the sensor shaft. While the slot is not functional during coupling operation it provides a way to machine the coupling, generate the flexure, and then anodize it. As a last step, the machined sJot permits pressing dielectric bushing into the coupling without damaging the HELI-CAL® Flexure.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# ASM6845

CHALLENGE

A manufacturer of force transducers wanted to integrate our coupling into one of their machines. They needed to transmit torque from one section to another, while maintainjng a precise articulation between the two assemblies. Using a HELl-CAL® Flexure they are able to accomplish both requirements.

SOLUTION

The r.wo assemblies mate and articulate with a sphetical surface inside a round bore. This arrangement allows for angular movement, while always keeping Lhe assembly centerlines intersecting. It makes for a very low friction swivel joint.

By attaching one end of our coupling to the assembly conlaining the bore, and the other to tbe assembly containing the spherical smface that rides in the bore, torque is transmitted between the Lwo pieces. Because of the needed offset of the flexure with respect to Lhe spherical surface, the flexure goes through a contorted "S" curve misalignment with the centerlines of the assemblies intersecting away from the center of the flexure. The HELi-CAL Flexure is fully capable of this with proper design.

This successful application is another verification of the HELT-CAL Flexure's ability to accom­modate difficult misalignment requirements and still perform the task or Lransferring torque.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling # 6499X1

CHALLENGE

The application called for a 90-degree universal joint on a vacuum chamber conveyor system. The joint could not cause particles to develop or require lubrication that would contaminate the product being transported on the conveyor. Secondly, there was a need for a flexible coupling to be used in conjunction with the application but not part of the universal joint.

SOLUTION

To meet the requirement of using the proper material in a vacuum atmosphere, 15-SpH stainless steel was chosen. The HELT-CAL® Flexure was produced from a single piece of material allowing for 90 degrees of angular misalignment without any moving parts (which eliminates debris from forming). To develop the proper U-joint with the desired end connections, three samples were made for the customer to test, evaluate, and qualify.

For the flexible coupling, a standard catalog u11it was tested originally but a special end connection in a turned-down hub was required. The final unit was made from 15-SpH stainless steel as well.

ANSWER

HELI-CALFlexured Universal Joint# 9581X2

HELI-CAL Flexure Flexible Shaft Coupling# 7570

CHALLENGE

A CNC machine attachment manufacturer required a flexible coupling to connect a servo motor to a ballscrew on the X and Y axes. This was a retrofit; therefore, the coupling was confined to a limited-size envelope. It must be torsionally stiff with a relatively high torque capacity. The minor misalignments were primarily associated with the assembly of each machine.

SOLUTION

The application engineer's challenge was to find a cost-effective solution in addition to meeting all of the customer's performance needs. initially, a sketch of a proposed design was sent for the customer to review. Upon design approval, samples were sent for testing and evaluation; after completion of testing, a 2-year order was received. This customer had been a prior California Helical customer who had moved to Oregon. They were using two competitor's couplings. Helical.'s representative visited the customer and was able to offer them a more cost-effective and higher-performance solution. With communication between the representative, the customer's engineer, and our application engineer, this whole program was reso]ved in a relatively sh011 time (a three-month period).

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling# 7444

CHALLENGE

In September a customer called regarding a switch on a commercial appliance. He had just picked out a standard Helical flexible coupling to test their prototype concept. "How can Helical help?" The first step was getting information regarding the customer's project so that Helical's application engineer could start the design process. The customer was willing to use the clamp-type attachment over the set screw attachment even though it was more costly. The shaft tolerance was plus or minus .003 inches. This provided an additional challenge for the holding ability of the clamp.

SOLUTION

Life testing of 100,000 cycles was necessary to assure the customer of the reliability of the proposed coupling. The customer was sampled with both a set screw and integral clamp standard coupling plus a special Helical flexible coupling for test and evaluation. It is important to keep communication between Helical, the representative and the customer's engineer open as in this case a new engineer came in to finish the evaluation. ln March, only six months after the original contract, the design of a special Helical flexible coupling and its testing completed, an order was received at Helical for 5,000 pieces with monthly deliveries. This was in 1994. The company has been sold twice over the past 5 years, but they are still using this Helical coupling.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling #7149-7mm-7mm

CHALLENGE

This customer had an application connecting a stepper motor to a lead screw on an infrared imager. They required a specific compression spring rate while maintaining a certain amount of flexibility for angular and parallel misalignments. The compact imagers use an LED array to scan the IR band to detect heat losses from homes, buildings, and/or equipment. The customer needed a low-cost solution to maneuver the LED array.

SOLUTION

Where the customer application requires a special design, communication between the customer and Helical's engineers is extremely important. To be sure we understand what the engineer.is attempting to do, we send a sketch of our concept of their situation. Then, with the customer's approval, a sample is provided for testing and evaluation. lf necessary the design can be adjusted, and fine-tuned and attachments can be adjusted in a timely manner. It is a team effort between the customer, HelicaJ's representative, the engineer, and production to service the application to a satisfactory completion.

ANSWER

HELl-CAL Flexure Flexible Shaft Coupling # 9580Xl

CHALLENGE

A customer using a flexible coupling in a Linear Actuator needed to have a more dependable unit with no backlash. The original customer contacted us in November and needed a quick response. "is it possible for Helical to help?'' Testing had to be accomplished by the customer's outside testing house before final approval on the Helical flexible coupling could be given.

SOLUTION

To obtain superior strength and high torsional stiffness, 17-4 pH stainless steel was chosen. Working through Helical's representative, application engineer, and manufacturing, the first sample was delivered ten days after the original contact. Testing showed that it was necessary to design a new flexible coupling because of size restraints. There were some minor adjustments made to the second version, which still had to go through the test & evaluation program. The communication between the customer, representative, and Helical was critical in completing the project in a timely manner. AJI of this was accomplished between November 5th and April 30th to the satisfaction of the customer, and the first 500-piece order was placed.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling# 7490Xl

CHALLENGE

A manufacturer of plotter/cutter equipment, used to make posters, came to us requiring a U-joint with zero backlash capable of compensating for .200 inches of axial travel. In the assembly of their system, there was also the need to compensate for angular and parallel misalignments.

SOLUTION

After discussing the application with the representative, Helical's application engineer proposed a solution. A sketch was then forwarded to the customer for review. Upon approval, a sample was produced and sent to the representative to hand deliver. The test and evaluation lasted for approximately eight weeks. A full production order was placed two months from the time of inception. This shows the importance of cooperation and communication between the customer's engineer, Helical's representative, and the application engineer in providing the appropriate HELI-CAL ® Flexure.

ANSWER

HELI-CAL Flexured U-Joinl # 9584

CHALLENGE

A current customer of Helical inquired regarding a special application they wanted to resolve on a material handling machine used in a CJean Room atmosphere. The need was for a coupling to retain a high torque and torsional stiffness while at the same time being soft in lateral bending. Reliability was a critical requirement, as a failure could cost the customer hundreds or thousands of dollars in broken silicon wafers.

SOLUTION

To make sure everyone understood what was needed on this particular application, a sketch was forwarded to the customer for review, comment, and suggestions for any changes. When the concept was approved samples were sent. It is important that when a design is OK'd, a sample be forwarded as soon as possible. We attempt to keep this in the two/three-week time frame. The first sample group was sent in September. The customer asked that the unit be made laterally softer. Alterations were made to the design and a second group was sent a month later. In November another sample was sent, but with the addition of a keyway. 1n January the initial order was placed. The coordination of all (customer's engineer, rep, company engineer, and manufacturing) makes the Helical design program a unique and advantageous solution.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling # ASM7614X3

CHALLENGE

A multinational glass manufacturer supplying vehicle and aircraft companies was having difficulty keeping their production equipment operating. The biggest concerns they were having were high maintenance costs and the need to replace the U-joint on an average of every 2.5 months. The necessity to exchange the U-joint caused downtime and delay in manufacturing.

SOLUTION

The solution must allow for 23 degrees of angular misalignment and operate at 3600 RPM. A sample U-joint was sent to the customer's engineer to become familiar with the HELI-CAL® Flexure concept and to run a preliminary test. Being satisfied with the evaluation, the final design was shortened and used an integral clamp attachment. There are three different bore combinations. The customer commented it looks cleaner and saves them approximately ten thousand dollars annually.

ANSWER

HELI-CAL Flexure U-Joint # 9654-28.6mm-24

CHALLENGE

In a hand positioning device, the customer was using a plastic universal joint which broke apart. A higher temperature than normal was involved as it is heat-sealing equipment that is being manufactured. The U-joint operated at 45 degrees in positioning a plate into the proper location. The material also must be electrically non-conductive.

SOLUTION

With a Helical application engineer discussing the problem with the customer's design engineer, it was possible to save time in completing the development of the proposed U-joint. With good communication through the representative salesman, the final solution was completed; however, it took four different design variations and samples to satisfactorily pass the test and evaluation program.

ANSWER

HELI-CAL® Flexure U-Joint # 9653X3

CHALLENGE

A long-term customer asked if we could add a small amount of elasticity to a line of machine tool holders that enhance the life of taps involved in CNC, metal tapping.

The new generation of CNC mills is full of capability and capacity. Machining tasks of years past gave rise to machinists who developed tricks and specialized procedures that enhanced the machining of complex items. While those skills are still valuable, the world of CNC machines has added precision, capability, and precision to the world of machining. One small problem exists, however.

It is impossible for a CNC machine to perfectly follow the needed motion for rigid tapping. The motion profile is usually very close, but not perfect. As a result, tap life is shorter than optimal.

SOLUTION

By using the HELI-CAL® Flexure to compensate for the minute differences between tap geometry and the motion provided by CNC mills, tap life in rigid tapping applications has been greatly extended.

Since the company involved has the ability to manufacture the spring blanks themselves, they have called upon Helical’s Generate-Only service to machine the Flexure. As always, Helical’s engineering staff computed the Flexure geometry to meet the customer’s needs.

ANSWER

HELI-CAL Generate-Only, Flexured Machined Springs: G1145, G1146, G1157, G1159, G1160, G1161, G1162, G1167, G1170, G1171, G1184, G1185, G1197, G1198, G1199, G1200, G1204, G1207, G1209, G1210, G1215

CHALLENGE

In the production of cathode ray tubes (CRT) for television use, the front face of the tube is ground to provide a smooth, uniform transparent surface. To accomplish this end, mechanisms that survive the abrasive environment of ground glass must be created. In particular, a swivel device that keeps the grinding media uniformly parallel to the glass with transmitting torque to the grinding operation is required.

SOLUTION

By using the HELI-CAL® Flexure in a triple start configuration and adding attachment features, this consumer product producer was able to enhance production.

ANSWER

HELI-CAL Flexured, Machined Springs: TSR2490, TS2491, TS2502, TSL2510

CHALLENGE

This project did not start as a challenge, just a standard catalog Helical flexible coupling ACR037-2mm-2mm. The original customer transferred the value-added package to another company. The second customer needed to verify the holding force and capacity of the integral clamp. That is when the challenge began.

SOLUTION

The customer requested verification on the specification of coupling material, anodize, screw size, and physical dimensions. Their biggest concerns involved the integral clamp. Tested were the location of the cap screw used, screw size, bore tolerance, and seating torque of the screw. Only slight changes were necessary to satisfy the customer, but to keep the record straight a new part number was given.

ANSWER

HELI-CAL Flexible Coupling 8703-2mm-2mm

CHALLENGE

This project involved a universal joint with the requirement to operate at 15 degrees angular misalignment, 50,000 RPM, with a life of 120,000,000 cycles.

The method originally used failed to give the desired life and smoothness in operation. The end product is a Surgical Bone Saw.

SOLUTION

Helical's application engineer, working with the customer's design engineer, was able to reduce the number of parts on the original design. This allowed the customer to improve his finished product and make it easier for the surgeon to use. The final design is made complete in a single homogeneous piece of l 7-4pH stainless steel material.

The testing program consisted of 15-degree angular misalignment, 45,000 RPM with a

complete cycle of: ON 10 seconds • OFF 10 seconds. This cycling was done 108,000 times, giving a life of at least 810,000,000 cycles.

ANSWER

HELI-CAL Flexured U-Joint # 9491

CHALLENGE

The sophistication of medical equipment continues to grow yearly, and everyone potentially benefits from the new and grand strides being made. This equipment often puts elastic components into demanding, and critical, environments. Like aircraft, all components need to be of high quality and of known life expectancy.

The ability to incorporate an elastic element with greatly beneficial integrated attachments is demonstrated by this application. The addition of a flange, a treated feature and hex drive makes this machine spring easy to install and most effective as an extension spring.

SOLUTION

By using the HELI-CAL® Flexure in a Single Start, extension spring configuration with specific attachment features, this medical valve spring has been configured to be threaded into place and meet the performance requirements of axial stiffness at varying temperatures.

ANSWER

HELI-CAL Flexured Machined Spring: 20110

CHALLENGE

In a machine used to slice bits of frozen specimens for microscope slides, the customer was attaching two shafts with two couplings and two universal joints. To accomplish this

slicing a hand wheel is used to position a linear transducer.

In the prior system, the customer was attaching a coupling that allowed five (5) degrees of angle, and at the opposite end of the shaft a universal joint capable of twelve (12) degrees of misalignment. There are two different shaft lengths used in this instrument.

SOLUTION

With the international representative sending information and drawings from the customer to show details of the system, Helical's Application Engineer was able to design

units that met the two requirements. Normally, when the angular misalignment is five degrees we call it a flexible coupling, when the misalignment is above seven degrees it is

a universal joint. Here, we have both within the same HELi-CAL Flexure. Instead of six pieces to be assembled, the customer now has a smoother operation with only two Helical U-J's.

ANSWER

HELI-CAL Flexured U-Joint # D89496 and# D89497

CHALLENGE

A manufacturer of eyeglass lenses was using a British-made grinder. The grinding surface was directly below the universal joint which allowed for rotation as well as axial motion. The severe atmosphere was caused by glass dust from the grinding operation. The universal joint could not be lubricated as oil was not allowed on the lens. Running the U­-Joint 24 hours a day, the customer· was only getting a life of 2 weeks before failure.

SOLUTION

Through the coordination of the salesman, the Helical Application Engineer, and the customer's design engineer, a universal joint was designed that allowed for 18 degrees of angular misalignment plus the capability to extend an additional four inches in length. The assembly Helical produced gave them months of production without downtime for maintenance of the universal joint. It was a definite cost-saving unit for them.

ANSWER

HELI-CAL Flexured U-Joint II ASM991A2

CHALLENGE

A medical equipment manufacturer wanted to use a spring that provided (1) compression, (2) torsion, (3) lateral bending, and (4) lateral translation rates, all within one individual spring having an easy attachment method. They also requested three other springs with the same criteria except for different rates. All of this, and the springs must be lightweight and relatively inexpensive.

SOLUTION

Just being able to hit one elastic rate can be challenging, but four! Since the lateral translation rate needed to be as high as possible, it became the starting point for analysis. It is known that triple-start HELI-CAL Flexures are very high in lateral stiffness. Next, came the remaining three rates. Using first-class finite element analysis software, these three were quantified. A trend also appeared, showing that as the number of starts increased, the ratio of the remaining three rates converged. In fact, at five starts, the ratio was near perfect. At six or more, divergence was experienced, hence no benefit. All that was left was to select a coil thickness and OD to ID ratio that best fit the customer's needs. Combine the use of 7075-T6 aluminum for light weight and lower machining cost, and it's a done deal. (It needs to be said that this application died on the operating table due to medical reasons. But the ability to ratio elastic rates remains a solution looking for a sophisticated application.)

ANSWER

HELI-CAL Flexure Precision "Machine" Spring #'s ASM2341, ASM2342, ASM2343, ASM2344

CHALLENGE

The customer required a zero-backlash shaft coupling for a robot that would be used to perform human hip replacement surgery. They were using a high-torsionally stiff coupling but found that at high RPM the unit could shea, particularly when being subjected to higher-than-normal parallel shaft misalignment. The set screw attachment also proved unreliable for the torque being transmitted.

SOLUTION

A standard double flexure Helical coupling was used providing more reliable compensation of parallel offset between the shafts. The integral clamp attachment was
used, and the torsional stiffness of the stainless steel was adequate for the application. This standard catalog coupling was more cost-effective than the competitor's coupling.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling II MC7C 100

CHALLENGE

A catheter drive system used in connection with heart misalignment, a constant spring rate and electrical isolation (as even a minor current could shut down the heart) were all critical specifications in this design. The catheter rotates at 1800 RPM with only .6 in/oz maximum torque. The unit is calibrated each time to the patient. To be made of an electrical isolating material, it still had to be radially stiff, while axially flexible. Space was restricted as it must fit in the customer's design. The customer was also testing two other possible solutions to this application.

SOLUTION

Delrin is a non-conductive material but with low tensile strength. Therefore, the flexure must compensate for the soft material but give the largest amount of torsional stability possible. Tapped threads for an attaching screw would be easy to strip out, therefore, a set screw or integral clamp were not used. So a split hub was used as the attaching mechanism. The test and evaluation involved humidity and environmental concerns, as well as normal torque and torsional testing.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 6849

CHALLENGE

This application is on a small animal respirator where a linear drive is moving a piston back and forth supplying air to an animal. In an attempt to lower cost, the customer went to less precise parts and increased tolerances. However, this resulted in greater misalignments which increased maintenance frequency and decreased machine life. The customer wanted to have a flexible component using no lubrication as contamination was also a concern.

SOLUTION

Instead of the coupling rotating and transmitting torque, as with most coupling applications, this situation required a component with necessary axial and radial compliance. The radial flexibility had to be low enough for the Flexure to compensate for the misalignment between the drive and the piston. At the same time, it needed to be axially stiff to accw·ately transmit the back-and-forth motion. Locating the coupling next to the piston allowed the linear drive to move freely with no wear on the piston. Since the Helical coupling does not require lubrication, the customer's contamination concern was also resolved.

ANSWER

HELi-CAL Flexure Flexible Shaft Coupling II 5208

CHALLENGE

An existing customer had used the HELI-CAL Flexure in many unique situations. The function of this application is to administer medication through multiple syringes for lab research. These syringes are held in place by a clamp, fluid is then pushed through them by a slide driven with a lead screw. It was discovered that there was binding between the slide and its support rails causing uneven flow of medication and inaccurate readouts of the amount administered.

SOLUTION

The customer determined they needed compliance in the rail supports to allow for variations in the spacing between the parallel rails that caused the slide to bind. A Helical coupling sample was given to the customer and installed at the end of each rail. Testing of the coupling proved the flexure had sufficient radial stiffness to support the weight of the rail and slide, and was flexible enough to prevent them from binding. This solution was used for a variety of drives ranging from two to ten syringes. This is another example of using a Helical coupling in applications other than to transmit torque.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling # 5848

CHALLENGE

In the design of a foot pedal for hands-free control of surgical tools, the customer needed to provide a pivot and a restraint torsional spring. The spring rates were unknown, only that it had to provide control with that "perfect feel." The pivot, restraint, and rotary motion were to be all in one nice neat package.

SOLUTION

This Helical Precision "Machined" Spring is used here as a torsion spring. The rate required is not precise, however, the ability of the machined spring to give both constraint and pivot functions was unique to the spring approach. The integration of attachment features and the ability to influence associated spring rates (in this case, the high lateral stiffness) allows this application to have the beneficial aspects of Value Engineering (one part, multiple functions). The number of pieces in the assembly was reduced, therefore, assembly time was also reduced. This was a Win-Win case for everyone.

ANSWER

HELI-CAL Flexure Precision "Machined" Spring 2254

CHALLENGE

The application was used on a Laser Control Adjustment Shaft. To permit the finest adjustment possible the customer wanted a precision adjustment as well as a smooth method to accommodate for misalignments within the system.

SOLUTION

During the design stage, the customer suggested they would produce the shaft with the two different O.D. and thread pitches. Therefore, this product is a Generate HELi-CAL® Flexure Only unit. This allows the customer, if they have the machiniJ1.g capability, to make the blank and Helical then generates the HELi-CAL Flexure into the unit. This becomes more cost-effective for the customer in certain applications.

ANSWER

Generate HELI-CAL Flexure Only product # G l 004

CHALLENGE

A medical respirator manufacturer needed help to reduce the size of their unit and cost. They were using a motor-driven ball screw to move a piston pumping air into a patient. The ball screw is supported at each end by bearings, one prevents axial motion on the ball screw. The customer wished to eliminate the thrust bearing next to the motor and use coupling as its support. The coupling had to be stiff axiaUy to limit axial movement and also stiff enough to support the ball screw.

SOLUTION

During the development stage, several samples were provided. The first sample had a right-hand flexure; however, it failed the life test. Even though the torque was bi-directional, it was greater in the compressed air mode. The next sample had a left-hand flexure improving the life ten-fold, but they still were not satisfied. The □ext improvement was adding stress relief holes at each end of the nexure. With this configuration, the life cycle testing requirement of 250,000 cycles was easily surpassed. This system also required FDA approval. After almost ten years, the coupling is still being purchased and utilized.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 6299-8-8

CHALLENGE

Because vibrations in a system this medical equipment company was manufacturing caused distortion between a camera and microscope, the customer required a torsionally stiff coupling. They had attempted to produce a flexible coupling themselves without success. They then went to a bellows type which operated 0.K.; However, the cycle life was too short. The customer's engineer was looking for a lower-priced coupling that would eliminate the vibration.

SOLUTION

During the discussions between Helical's application engineer and the customer's design engineer, it was found the coupling was used in a vacuum; therefore, it could not be anodized or glass-beaded. When the two engineers can converse, it expedites and aids in a better-designed coupling to meet a particular application. A sample is supplied for the customer to test and evaluate on his own equipment. lt also speeds up the process in obtaining the order, which, in this case, was for a lower-priced coupling that solved their vibration problem.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling # 7857-3-2mm

CHALLENGE

A customer's engineer telephoned saying they were redesigning their product and would probably be needing a new coupling. We were already supplying a special for them; however, they wanted the coupling to do more. The application is a motor to a rotary valve with an encoder disc to the turned-down end. In many cases, we do not know just how the coupling will be used in the customer's project. Communication between the customer, representative, and the application engineer is extremely important. With the exchange of sketches indicating the changes in the original Helical coupling (6200), it was possible to design the new coupling. During the discussions, different material was considered and torsional stiffness was a requirement as well.

SOLUTION

Samples were supplied for the customer's test and evaluation. We were also told a competitor's unit was being considered. Redesign discussions were started four years before the final flexible coupling was determined and ordered from Helical. The 01iginal projected usage was 250 pieces: however, the ultimate volume was in excess of 1000 units. As you see the customer's engineer must be kept in contact with for any possible changes required in their current product or for any new applications that may come up.

ANSWER

HELI-CAL ® Flexure Flexible Shaft Coupling # ASM 6596

CHALLENGE

The sophistication of medical equipment continues to grow yearly, and everyone potentially benefits from the new and grand strides being made. This equipment often puts elastic components into demanding, and critical, environments. Like aircraft, all components need to be of high quality and of known life expectancy.

The ability to incorporate an elastic element with greatly beneficial integrated attachments is demonstrated by this application. The addition of a flange, a treated feature, and a hex drive makes this machine spring easy to install and most effective as an extension spring.

SOLUTION

By using the HELI-CAL® Flexure in a Single Start, extension spring configuration with specific attachment features, this medical valve spring has been configured to be threaded into place and meet the performance requirements of axial stiffness at varying temperatures.

ANSWER

HELI-CAL Flexured Machined Spring: 20110

CHALLENGE

During the Gulf War, a TV battlefield interview was conducted with an M-1 tank in the background. The tank was making such a lot of noise that the interview was compromised. The source of all this noise was a night vision system externally mounted to the tank. The manufacturer of this system was about to lose its contract because of the
noise and related inefficiency. Within the system, an amateur suspended by two wire wound compression springs comprises the moving parts. Basically, a linear motor is created that operates in resonance. The end function of this resonance Oinear motor) is that of a pump supporting an infrared, optical scanner. The noise was traced to the wire wound spring. The touching coils made noise and consumed some of the potential efficiency of the pump. Could a machined spring positively influence both of these issues?

SOLUTION

After serious review and analysis by Helical and the customer's engineers, the decision to attempt a Double Start (DS), high-strength steel HELi-CAL Flexure was decided upon. From the first test, the application for this concept proved successful. By natw·e, the end coil of a machined spring does not contact or wind into adjoining coils; hence, no contact and no noise. Furthermore, no contact and increased efficiency. The resulting system was better than it had ever been. The company's contracts were saved and potential layoffs were avoided.

ANSWER

HELI-CAL Flexure Precision "Machined'' Spring# D82412

CHALLENGE

This naval weapon is used for long-range interception of threatening targets. The current missile uses springs to deploy the fins when the missile is fired from its storage canister. The manufacturer of the missile had a supplier for the spring but was now looking for a second source. The material used in this spring is "Beta C" which is the highest strength commercial grade titanium known. Even though this particular titanium was new to Helical, we were willing to learn to fabricate a new product with a new material.

SOLUTION

Helical was contacted as that alternate supplier. The result was that a product of higher quality was delivered on a timely basis at a competitive price. The missile manufacturer awarded Helical the Outstanding Supplier Award in May 1988. Even though the manufacturer's business has declined, the original engineers working on this project continue to use the Helical Precision "Machined" Spring in other applications. Currently, two spin-off applications are active: (1) on the space station, electrical interface probe, and (2) on chemical industry equipment.

ANSWER

HELI-CAL Flexw·e Precision "Machined" Springs # L2101 and R2102

CHALLENGE

An inquiry received through a trade publication requested information on machined springs. The literature was forwarded to the design engineer. With the help of the representative, operational information was returned to Helical on the Proposal Sheet for a compression spring. The electronics were mounted on a vehicle in a vertical position, the spring was to allow the board to float compensating for movements over rough terrain. Through these gyrations, the electrical connections must be maintained.

SOLUTION

A sketch of a suggested solution was sent to the customer's engineer for review. When accepted, four no-charge samples were forwarded for testing and evaluation. The spring eliminated two additional parts as they were incorporated into the Helical machined spring unit. The team effort by the representative, application engineer, and the customer's design engineer made it possible to resolve this spring project in only five months from inquiry to order (250 pieces).

ANSWER

HELI-CAL® Flexured Precision Machined Spring # 2598

CHALLENGE

The customer is involved in the nuclear industry providing engineering for the entire power plant. In addition, they furnish equipment for repair and maintenance of the facilities. One of the inspection tools is required to probe inside the reactor coolant tubes.

The connection between the motor and sensor must have the ability to turn and flex while verifying the condition of the tube.

SOLUTION

The final design allows for 35 degrees of angularity while transmitting the torque and motion necessary for the sensor to perform its function. The attachment is the normal two set screws at each end, but on the very end, there is another set screws.

ANSWER

HELI-CAL Flexured U-Joint # 9495

CHALLENGE

"The customer is designing a machine to inspect silicon chip wafers and they need to be able to rotate, tilt, and orbit the wafer via a joystick control. Basically, the flexure would be required to angularly bend through 30 degrees, but they require the minimum torsional wind-up we can offer. The material would have to be stainless steel."

Several different means of transmitting this motion had been tried but failed due to a lack of positioning accuracy attributable to either backlash or torsional flexibility. There were almost daily FAX's and telephone calls to the international representative as well as direct contact with the customer. Design and production were pushed to the limit to supply samples of finished parts.

SOLUTION

Meeting the customer's requirements under time constraints caused additional design and production pressures. The final configuration met the specifications plus gave the life
expectancy they wished. With Helical's ability to resolve the strict requirements in a
timely manner, the customer was able to obtain the big order they were trying for.

ANSWER

HELI-CAL Flexured Universal-Joint# 9499Xl

CHALLENGE

A customer already using a number of different Helical standard catalog couplings asked about the feasibility of a modified coupling with two "stand-offs" integrated within the coupling. These would act both as a hard stop and a trigger for a servo.

SOLUTION

Close communication between Helical's application engineer and the customer was maintained as there were many dimensions and specifications to be verified so Helical could provide samples to be tested. During the evaluation, the customer asked for additional changes from the original concept. Helical was able to produce the coupling more efficiently, therefore, it also lowered the cost. Giving a sample for the customer to test and evaluate in his particular application assures he is obtaining the appropriate Helical product for his needs. On this particular application, it took only three months to accomplish everything and receive the first order.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling# 7850Xl

CHALLENGE

The customer had planned to use an AE087 or AEl00 as a basis to connect a potentiometer to a control lever. The operating atmosphere included both salt and dirt, plus having a high parallel misalignment. The customer wanted to use a "D" bore to fasten the lever to a shaft, and then connect the coupling to the "pot." Because of the small "D", the cost increased beyond what the customer was willing to pay. Communication between our representative, the customer's design engineer, and Helical's Application Engineer made it possible to provide a cost-effective solution to their project. During these conversations, a method of protecting the assembly was discussed.

SOLUTION

By integrating the HELI-CAL Flexure and shaft, then "press fitting a lever arm onto the shaft, the customer received a supe1·ior product at a reasonable price. They also saved by having fewer parts to inventory and eliminating one subassembly. A second subassembly was eliminated by having us enclose the unit into a sheet metal covered box. This was the fu·st time we were involved in this type of assembly work.

ANSWER

HELI-CAL Flexured Assembly# ASM6920X2

CHALLENGE

An old Helical customer who manufactures laboratory equipment contacted us with a new application. In developing a new chemical mixer, they placed a blind assembly of the coupling directly over the mixing bowl. While testing an aluminum coupling, the wear in the blind area caused aluminum dust to fall and contaminate the chemical being mixed. It was necessary to find the proper material that gave the desired life and did not interfere with the chemical being mixed.

SOLUTION

Using Delrin (plastic), which is a chemically inert material, resolved the contamination situation. The HELI-CAL Flexure met the torque and misalignment specifications and allowed for a quick disconnect of a new stirring paddle.

ANSWER

HELI-CAL Flexure Coupling# 6770Xl

CHALLENGE

One of the largest manufacturers of entertainment lighting systems for nightclubs and concert halls came to Helical Products during development of a new generation of computer-controlled lights. The high-end lighting system needed a flexible coupling to connect the stepper motor and leadscrew that move the lights in rapid and various directions. Another challenge existed because of the high temperatures and exposure to UV light.

SOLUTION

In designing the coupling to meet all of the customer's requirements, cost was an important factor that had to be considered. The material used to overcome the temperature and the UV light was Aluminum 7075-T6. With Engineering working closely with Manufacturing, Helical was able to produce a cost effective flexible coupling.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling # 6823.

CHALLENGE

A manufacturer of office equipment wishing to help alleviate the "carpel tunnel problem" that is so common in today's workforce was designing an easy method to raise and lower a computer table top. They wanted to allow people of different heights sitting at the same desk to easily and quickly adjust the table top height to fit their own needs comfortably. To accomplish this task a 90 deg ee universal joint was incorporated between a hand crank and a lead screw. The customer considered a gearbox but this idea was abandoned due to cost.

SOLUTION

It was necessary to use steel material to give the necessary torque and life required by the customer. 15-5pH was the material chosen for longevity and possible abusive use. The HELi-CAL Flexw·e has 17 coils to allow the required 90-degree misalignment.

ANSWER

HELI-CAL Flexured U-Joint # 9474

CHALLENGE

A specialty machine manufacturer designing an orange juice packaging machine had some out-of-the-ordinary misalignment requirements. The universal joint needed to compensate for 6 degrees on each side of the center and at the same time extend and compress a quru·ter of an inch. These movements were needed while filling the containers with juice. The customer was unable to find a coupling or u-joint to allow for all of these misalignments at the same time.

SOLUTION

In the final design, it was possible for the coupling to allow 12 degrees angular (six degrees in each mode) and three-fourths total movement (three-eighths in each mode). There are two couplings used on each machine, oscillating and rotating in opposite directions.

ANSWER

HELi-CAL FLEXURE Flexible Coupling II 6680.

CHALLENGE

In the treatment of waste water in ponds and small lakes, "aerators" are used to stir and force air into the water to help in its purification. The most common "aerator" draws air down the propeller shaft to the propeller where it mixes with the water. The "Cardin style" u-joint that was being used restricted the airflow; therefore, the efficient flow of air was limited.

SOLUTION

The Helical coupling allows air to be drawn through the flexure and then down the shaft to the propeller which stirs the water. The coupling also supported the propeller shaft at the motor end, eliminating the need for a bearing.

ANSWER

HELI-CAL Flextu-e Flexible Shaft Coupling# 6577

CHALLENGE

A manufactw·er of battery-powered carts for disabled people came to Helical because of a problem with their steering system. They were using a "cardin style u-joint" to connect the steering to the front wheels. Their concern was that the handlebars could be pulled from the driver's hands if a cub was hit by the cart. Numerous hand and wrist injuries resulted from these sudden impacts, jei·king the handlebars from the driver's hands. Because these fow· wheeled vehicles have been in production for many years, any universal joint replacement had to fit al1 the carts. It was decided that because the speed is slow (max 5.0 mph) and thorough testing would be performed, this would be an acceptable application of the HELI-CAL Flexure.

SOLUTION

Combining the needed torque capacity with the necessary torsional flexibility was required. Several samples were provided to assist the customer in finding the torsional flexibility that gave good feedback while driving. The universal joint also had to have enough windup capability so that when a driver impacted an object, they could still hold the handlebars while the front wheels turned. The u-joint was tested repeatedly by the customer's technician driving a cart into cw-bs and other obstacles. These tests proved the universal joint could solve this application to the satisfaction of the customer.

ANSWER

HELI-CAL Flexw-e U-Joint # 9467X2

CHALLENGE

A manufacturer and designer of human-sized puppets had a unique challenge of how to move the head of a large five (5) foot-tall puppet. The position of the operator is approximately 75 degrees from the puppet's head. It was extremely important to have the head move in a fluid, life-like motion. Consequently, the mechanism joining the operator's controls to the head had to function smoothly, be constant velocity, and have no backlash.

SOLUTION

Being able to provide the customer with a one-piece U-joint reduced the installation and maintenance time. The customer called and discussed their requirements. When an engineer talks to an engineer it simplifies the design process. It was possible, within 4 weeks from the original contact, to design, supply a trial sample, and receive the first order. This led to another similar application on another puppet, only on the opposite end of the body.

ANSWER

HELI-CAL Flexured U-joint II 9522

CHALLENGE

A repair and maintenance company called asking for help in replacing a U-joint that the manufacturer was using on its original equipment. Over a period of time, there was wear in the multiple-piece unit which caused backlash, increased maintenance, and reduced efficiency; smooth operation of the equipment was lost. It was a retrofit application; therefore, the new unit had to fit into the allocated space and provide 30-degree angular misalignment capability. There were two U-joints on each unit, with a single motor in the middle, which means each end rotated in opposite directions.

SOLUTION

To reduce the stress level because the U-joints operated in opposite directions, the HELI­CAL Flexures were generated with left-hand and right coils. This allowed the HELl-CAL Flexure to always operate in the windup condition. One end was pinned in place, while the other had a quick disconnect attachment. To ensure the unit would not disengage while in operation, the slots were machined to prevent this from happening. Ease of installation, low maintenance, and requiring no lub1·ication was enough of an incentive for the R.M.O. company to purchase hundreds of these U-joints. There was a repair and maintenance shop on both the West and East coast. It is natural when an application has been solved in the field to go to the original manufacturer to offer our solution, however, they were not interested.

ANSWER

HELI-CAL Flexured U-Joint L9134 and R9134

CHALLENGE

The customer wanted to absorb shock on an automatic sliding door. The HELi-CAL Flexure was to act as a flexible coupling transmitting torque and to take up misalignments; plus, be a spring with compression and torsional requirements. The new design was to be as compact as possible and become part of the door. The prior mechanism operating the door was accomplished through hydraulics located in the basement.

SOLUTION

Since the customer was working on a new project, the rates required to make the system a soft and smooth operating system were unknown. It was just to start somewhere and adjust from that point. The customer asked to have the first unit with a 1000 lb/in compression spring rate. We supplied them with a coupling/spring that was 1.0" OD x 2.0" L with 3 coils. The final design performed and looked much different - .875" OD x 4.625" L with 17 coils. There were two spring rates: Compression 125 lb/in; and Torsional 144 lb/in. This progression of development took approximately 2 years and 10 sample variations. Once designed and production started, the customer was always attempting to find a less costly unit that could replace the Helical coupling; however, throughout the life of the patent, they were unable to find a product that gave them the needed life at a lower cost.

ANSWER

HELI-CAL Flexure Shaft Coupling # 1536

CHALLENGE

In this customer's application they are making yarn, and then winding the material on cone-shaped spools for high-speed weaving machines. The yarn is placed so it will not become tangled and hold itself on the spools as it comes off. Their machine operates 24 hours a day at two speeds, 12,000 and 12,500 rpm. The coupling originally used was not constant velocity and the cycle life was too short.

SOLUTION

There were two couplings or u-joints that rotated in opposite directions; therefore, to operate in a windup condition the HELI-CAL® Flexures are right and left-handed. Also, to allow a 10-degree angular misalignment, it was necessary to use five coils to accommodate the angle and not have coils touch and wear to shorten the lire or the coupling. For ease of connecting and disconnecting, an integral clamp system was used. To fit into their normal maintenance

program of 100 days, it was necessary for us to increase the first design from 5/8 inch outside diameter to 3/4 inch. This extended the life of the HELI-CAL Flexure to the customer's life expectancy. They were happy with the very smooth operation of the coupling. We are still

selling these couplings 26 years after first developed.

ANSWER

CHALLENGE

A call was received from the customer asking for help as they were having a quality problem with their current coupling supplier. There were two couplings with different shaft sizes, but they used a quarter-inch (.250) spline at one end. The coupling was connected to an optical disc with a spline bore mating with a spline on the shaft.

SOLUTION

To help the customer properly evaluate the HELi-CAL 49 Flexure, a no-charge sample flexible coupling for each bore size was sent to them to test and evaluate. It was important for the customer's engineer, the representative's salesman, and Helical's application engineer to communicate with each other to keep the ball rolling in finding the answer. Should there be a need to revise the end product, this allows the information to be passed along in a timely manner. There is no need to tear down a competitor's product to promote the HELI-CAL Flexure Flexible Shaft Coupling.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# DS6330-12-8 and DS6330-8-8

CHALLENGE

The challenge was simply to connect two shafts together on seismic reading equipment; however, the real question was, "Can Helical supply a zero-backlash shaft coupling that wll perform in severe climate conditions?" The unit being used was a multi-piece plastic and metal coupling which was unable to withstand Antarctic temperatures. Reliability was of great importance as the equipment was left out in the elements for long periods of time.

SOLUTION

One of Helical's standard catalog flexible couplings met all the characteristics that were required. This was an inexpensive solution to their situation. The 'no maintenance' and 'no lubrication' was an added advantage. Here the solution was found with a standard flexible coupling from the Helical catalog.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling# ACM0S0-4-4

CHALLENGE

Almost two years after catalog information was sent to this customer they asked for help in supplying a coupling to a servo motor to be used on the x-axis of an integrated circuit board handler. An aluminum, double-start coupling was offered for testing and evaluation on their prototype machine. They felt more secure with a stainless steel coupling.

SOLUTION

The final solution required shorter couplings to accommodate the space allotted and meet the torsional stiffness requirement needed for the application. A standard catalog, stainless steel coupling met the specifications on the y-axis; however, for the x-axis, a special unit coupling was designed for the customer.

ANSWER

HELI-CAL® Flexure Flexible Shaft Coupling# 7647-24-16mm (x-axis)

HELI-CAL Flexure Flexible Shaft Coupling# HCR 112-16-12 (y-axis)

CHALLENGE

There is nothing like a consumer product to place one’s industrial goods in front of all to see. In this Flexure Fact an industrial user of Helical’s Flexures got the idea that the world of golf might benefit from a Flexure incorporated into the head of a putter. The picture below shows the Flexure installed and ready to putt.

SOLUTION

By using the HELI-CAL® Flexure in a single start configuration and calling upon Helical’s knowledge of elasticity, just the right amount of stiffness was selected to provide the golfer better feel for coaxing the small white ball into the cup on the green.

ANSWER

HELI-CAL Flexured, (Generate Only) Machined Spring: G1173

CHALLENGE

The customer was having difficulty with the connection of a potentiometer to their rotating system. It was necessary for them to make a special shaft in-house to attach to a coupling. This created an additional increase in the price of their product and troubles in the installation of the overall system.

SOLUTION

It was possible to combine the shaft and coupling into a single unit. A design concept drawing was sent to the customer; the design was accepted, and then a second coupling was added to the system. The second unit is used on the same system with a slight variation in O.D. (outside diameter) and length. The development and approval was accomplished in a very short time.

ANSWER

HELI-CAL Flexure Flexible Shaft Coupling# 7536-6
HELl-CAL Flexure Flexible Shaft Coupling # 7540-6