Jaw Clutches and Couplings

Jaw clutches and jaw clutch couplings are generally used for moderate speeds where a relatively inexpensive device is required for positively connecting or disconnecting two rotating components and where engagements and disengagements are not too frequent.

Square jaw construction is used where engagement and disengagement in motion and under load is not necessary. Engagement is only possible when the two halves are in position, so that jaws of the shifter half can enter the mating pockets of the stationary half. Square jaws will transmit power when rotating in either direction.

Spiral jaw clutches and jaw clutch couplings are made either right or left hand. A right hand clutch drives when turning clockwise as viewed from the plain end of the driving half. Spiral jaws permit shifting more readily, and are sometimes used where the clutch must be engaged or disengaged when in motion. Such applications should be limited to low speeds and moderate loads. Spiral jaws will transmit power in one direction only and are furnished right or left hand, as per your requirements.

Jaw clutches and jaw clutch couplings are available in cast iron or cast steel, in square jaw, and right or left hand spiral. Cast iron jaws are normally ground smooth, and machined jaws are furnished only when specified.

(In heavier applications where they must be disengaged under load and in motion, machined jaws are more suitable, as they provide uniform contact over larger surfaces and result in greater ease of operation.) Cast steel clutches can be furnished with or without finished jaws, for more severe service.

The sprocket half of a clutch is free to turn on the shaft. If it is to remain disengaged for long intervals, it should be bronze bushed. Collars prevent lateral travel. Both an internal collar and an external collar are required.

On jaw clutch couplings, a bronze bushing is inserted in the driven half. The driving shaft pilots into this bushing, maintaining concentricity and supporting the end of the shaft.


The size required is usually based on the shaft size. (There are 11 sizes.) Jaw clutches and jaw clutch couplings are usually supplied complete with:

  • Shifter lever with yoke
  • Bronze shifter band
  • Fulcrum
  • Set collar