Abstract: The invention is a unique combination of a pressure switch, a temperature switch, and a check valve which act to automatically control the on-off operation of a centrifugal pump in response to an external flow demand.

Abstract: A drive mechanism is disclosed for use in a change dispensing apparatus for automatically relieving a jam-up of the dispensing mechanism. The drive mechanism includes a drive shaft having a cam member secured to one end, a driven shaft with a support member secured thereto and positioned adjacent the cam member, a pair of arm members rotatably mounted on the support member and which are spring urged into engagement with the cam member to transmit the rotation of the drive shaft to the driven shaft. Upon the stopping or slowing down of the driven shaft, the cam member will rotate with respect to the support member thereby rotating the arm members against the action of the springs until the torque exerted by the springs is greater than the torque by the cam member on the arm members resulting in a reverse rotation of the support member and the driven shaft which rotation acts to relieve the jam-up of the dispensing mechanism which caused the stopping of the driven shaft.