The advantages of anti-backdrive gears

A Precision Motion (Cofil) product story

Edited by the Engineeringtalk editorial team Oct 27, 2000

Unique advantages of anti-backdrive spur gears include increased efficiency (80% is common), reduction ratios of less than 25:1 (even 1:1), bi-directionality, and simple, compact construction

Self-locking mechanisms are used in applications where it is undesirable for the output to back-drive the input, often independently, but sometimes as a secondary fail-safe for a electrical/mechanical brake.

Frequently worm-screw mechanisms are used, however these have several inherent disadvantages namely that total dynamic irreversibility is impossible.

In order to get some degree of irreversibility, it is necessary to use a reduction ratio of greater than 25:1, resulting in efficiency of less than 50%.

Other solutions involve back-stops making them irreversible.

Unique advantages of anti-backdrive spur gears include...

* Increased efficiency (80% is common).

* Reduction ratio of less than 25:1 if required (even 1:1).

* Bi-directional.

* Simple, compact construction.

* Parallel input and output shafts are possible.