The Helical hallmark is flexibility in form and function. Designed from the start with your goals in mind and manufactured to exacting specifications, the HELI-CAL Flexure offers many problem-solving, performance-enhancing features.

The individual performance capability of each Flexure is determined by five factors: (1) coil width, (2) inside diameter, (3) coil length,

(4) number of starts and (5) material. Altering any one of these factors changes the performance characteristics of the “Flexure.”

Coil Width		Inside Diameter		Number of Coils

  Coil configuration

The Flexure’s signature characteristic , the “flex,” is a helical coil pattern that can be designed to affect torque, angular misalignment, parallel offset, torsional stiffness, axial movement and compression spring rate. For example, the six HELI-CAL Flexures illustrated display identical outside diameters and lengths. The effects of their variable characteristics—such as coil width, inside diameter and number of coils—are explained in the pictures above.

As the diameters are changed such aspects as torque...angular misalignment (bending moment)...parallel offset (radial load)...torsional stiffness...and compression spring rate, are altered.

As the coil is lengthened it also changes four of the five characteristics except the torque capacity. Also, it changes the product name from flexible shaft coupling to a universal-joint. The

U-joint normally has a larger angular capability.

A single start design has one continuous coil.

A double start has a second coil starting 180 degrees from the first.

A triple start has three interwound coils, each beginning 120 degrees from the other start.

When a multi-start helix is used (double or triple), the effect is to increase the torque capacity and torsional stiffness while reducing misalignment capabilities (angular and parallel).

The selection of the proper material to use in the manufacture of any HELI-CAL Flexure affects much more than just the torque capacity of the end product. Factors such as elasticity, fatigue, corrosion resistance, mass, magnetic permeability, operating temperature, availability and cost also play important roles. Because of the versatility of the HELI-CAL Flexure design concept, many materials not normally considered candidates for flexible couplings are acceptable for the construction of HELI-CAL Flexures. No other coupling offers so many choices.

In addition to the ability to alter the characteristics of the HELI-CAL Flexure you may have your attachment integrated into the final product. Typical attachment options might include:

• integral clamps
• set screws
• set screw at one end and an integral clamp at the other
• pins
• slotted hubs
• flanges
• gears
• removable caps
• threaded bores with a wrench flat
• or..whatever your design requires

Bore variations is another way to enhance the HELI-CAL Flexure as the bores include round...threaded...single or double-D..spline...keyway...tapered...or...or…

The HELI-CAL Flexure—or flexible section—can be custom designed and manufactured to your specifications. Whether you need high torque, angular or parallel misalignment, critical torsional stiffness, or precise compression spring rates along with special end connections, the HELI-CAL Flexure—coupled with your imagination—has unlimited possibilities.