This combination clutch-brake is similar to Mach III’s catalog model W4A2H-STH which has a ball bearing pilot on which a sprocket or pulley can be mounted. The pilot is driven when air is applied and held stationary when air is absent. An application called for the unit to have a 36 degree, 3L groove pulley with a 3.96 Inch pitch diameter which is too small to fit on the pilot. Mach III made modifications to reduce the size of the internal components so that the pulley could be incorporated directly into the sleeve.  

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