Braking device for a motor

Claim 1

A fluid operated brake device for an electric motor, including a housing with the motor shaft extending into the housing, the shaft having a brake disc fixed thereto within the housing, and including brake ring means carried in said housing, constrained against rotational movement and free for axial movement into and out of braking engagement with the disc, said brake device comprising, a fixed mounting plate on the housing; a movable mounting plate in a spaced apart, pivotal relation to said fixed mounting plate; brake stud means adjustably fixed to said movable plate for movement into and out of engagement with the brake ring means; compression spring means to normally maintain said movable plate in a first position with said brake stud means in engagement with the brake ring means to maintain a braking engagement with the brake disc; a plunger movable between a normally retracted position, permitting said compression spring means to maintain said braking engagement, and an extended position in engagement with said fixed mounting plate to pivot said movable plate to a second position with said brake stud means out of engagement with said brake ring means; means to actuate said plunger to said extended position by means of a suitable pressurized fluid when the motor is energized; said means to actuate includes a diaphragm housing, including mounting means mounting said diaphragm housing on said movable plate, and providing an inner chamber with a diaphragm spanning said chamber, said diaphragm housing provides an inlet port into said chamber on a first side of said diaphragm, said plunger extends inwardly through said mounting means and terminates in an enlarged head portion within said chamber, engaged against a second side of said diaphragm; said means to actuate further includes a normally closed solenoid actuated valve, wired in parallel with the motor to maintain said valve in an open position when the motor is energized, providing a flow of pressurized fluid through said inlet port against said diaphragm first side to displace said diaphragm in a manner so as to maintain said plunger in said extended position, said pressurized fluid flow being interrupted when said motor is de-energized permitting said valve to assume its normal closed condition and said plunger to move to said retracted position; an adjustable metering valve including manual control means, associated with said solenoid actuated valve, disposed in an exhaust passage in said solenoid actuated valve to control the rate of flow of pressurized fluid out of the diaphragm housing through said exhaust passage via said inlet port and the resulting speed rate of the braking operation of the brake device.