GB220733A - Improvements in or relating to electrical or electro-mechanical cut-out or automaticsafety devices for use with mechanical power transmission apparatus - Google Patents

Abstract

220,733. Mascord, G. W. May 26, 1923. Breaking-pieces for relieving strain.-In means for preventing shock due to overload, a collar e keyed to the shaft a driven by the prime mover is connected by a breaking-piece h of mild steel &c., with an attenuated central neck, to the gearwheel d driving the machine or to a block f bolted to the wheel. Turning with the gear-wheel is a casing j in which slides a plunger comprising a cylinder k and a piston l separated by a cushioning-spring k<3>. The head l<2> of the piston is normally pressed by a spring l<3> into a recess i<4> in a flange i<3> in a cup i bolted to the shaft a. A contact head k<2> on the cylinder j is shaped to bridge concentric conducting-rings n, o carried in an ebonite block m in the framing and connected by electric cables q to electric means either for stopping the electric or other driving-motor, for disconnecting a clutch used in the transmission, or for giving an alarm or actuating an indicator. When, owing to excessive resistance to the drive, the piece h breaks, the cam edges of the recess i' strike the plunger and press it axially to connect the rings n, o and perform the required operation. The contact head on the cylinder may engage contacts rotating with the wheel d and connected to the wiring by slip-rings. The contacts may be spring-supported, in which case the spring k<3> may be dispensed with. The plunger may be replaced by a lever which is rocked to close the electrical circuit.