Shaft collar

The shaft collar is a simple, yet important, machine component found in many power transmission applications, most notably motors and gearboxes.

Shaft collars saw few improvements until 1910 through 1911, when William G. Allen and Howard T. Hallowell, Sr, working independently, introduced commercially viable hex socket head set screws, and Hallowell patented a shaft collar with this safety-style set screw.

The invention of the safety set collar was the beginning of the recessed-socket screw industry.

It is common to machine small flats onto the shaft at the set screw locations to eliminate this problem.

This is due to the very high forces that can be created by a relatively small mass during impact, compared to a statically or gradually applied load.

In single piece designs, the non-tightened side provides negative force, as it must hold the collar open to allow it to be placed onto the shaft.

The bolt (exterior thread) has kerf cuts, making fingers, which are compressed onto the shaft as a nut is tightened over it.

[3] Shaft collars can be found in virtually any type of machinery and are frequently accessories to other components.