Flexible Couplings and Custom Coupling Capabilities > ONE-PIECE™ Flexible Disc Couplings > ONE-PIECE™ Flexible Disc Couplings > Item # R20T  
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Item # R20T, ONE-PIECE™ Flexible Disc Couplings

Some couplings are too stiff radially; they resist misalignment and thus overload bearings. Low Wind-Up and low Radial Loads are almost mutually exclusive, and always a compromise. The best compromise is found in flexible disc couplings-where rotational position is transmitted by means of tension in the discs. Whereas in a helical cut beam coupling the transmitting element is a cantilevered beam which cannot begin to have equivalent rigidity-and still provide radial flexibility. The graphs show clearly how much less wind-up there is in Renbrandt Couplings yet without excessive bearing load.

We also make special couplings to order, where existing parameters require them.



Overall Diameter (A)

2.00 Inch

C Maximum for Clamp Style

1.125 Inch

C Maximum for Set Screw Style

1.500 Inch

Misalignment (M)

3 º

Standard Material

7075T6 Aluminum

Special Options

Insulating Bore Liner
Stainless Steel

Std Lgth (B) - Set Screw Style

1.65 Inch

Flex Lgth (B) - Set Screw Style

0.75 Inch



The function of every flexible coupling is to transmit power or motion control from one rotating shaft to another that is not perfectly aligned, without excessive bearing loads.

But since the requirements for transmitting power are not the same as they are for controlling motion, couplings designed to transmit power might well be unsuitable for motion control and vice versa.

For instance, a resilient coupling made with rubber or springs would work well delivering power because it could absorb vibration and/or shock loads, but would not work well controlling motion. Here's why: In a motion control system, every component in the drive train (including couplings) affects the accuracy of the system by the amount of compliance (Wind-Up), Inertia, Friction, Backlash, etc. - things quite unimportant when transmitting power. A coupling that absorbs vibration must by definition, have Wind-Up, Inertia, or Backlash; whereas a true-motion control coupling must have no Backlash, low Inertia, and very low Wind-Up.

There are many applications, which are extremely sensitive to these factors. Today's encoders, for instance, can discriminate down to a few seconds of arc. (That's the width of a dime seen from 2 miles away) So you see how couplings can affect the success of your design.

Torsional Wind-Up is a very important factor. Notice in the graphs how outstanding RENBRANDT Couplings are.

Other manufacturers offer similar misalignment accommodation and low compliance - BUT NOT IN THE SAME PRODUCT.

The system must also be free from imbalance, vibration, and oscillation in order to prevent hunting - especially in closed-loop systems where a null balance is established between error signals. Since 1951 RENBRANDT has been building and improving Servo Couplings that provide reliability and long life free from maintenance - at moderate cost.


·  Delay caused by Wind-Up, Inertia, or Backlash

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Renbrandt, Inc. | Flexible Couplings