This air released coupling was custom designed for an application requiring a quick and simple means of inserting and removing rolls of material.  The face of the coupling (right) bolts to the machine frame.  Air is applied to the coupling when the operator presses a button which retracts the sleeve and exposes the slotted shaft end.  The operator can then slide a tanged shaft into the coupling.  When the air is released, the coupling sleeve closes to retain the shaft. 

The shaft is driven by a clutch which is connected to the extended shaft shown on the left side of the coupling. This coupling can be used with a clutch for stop/start or tensioning applications or a brake for stopping, holding or tensioning applications