Apparatus for monitoring elevator brakes

An apparatus for monitoring an elevator brake, the elevator brake having a rotating brake drum which is braked and held by brake shoes carrying brake linings which linings are pressed into contact with an outside surface of the brake drum, the brake shoes being mounted on a brake mechanism which is responsive to an actuating device for moving the brake shoes to engage the brake linings with the brake drum with a braking and holding force, comprising:

• a carrier adapted to be attached to the brake shoe of the elevator brake;
• a sensor attached to said carrier for monitoring a plurality of conditions of operating capability of the brake shoe when the brake lining carried on the brake shoe contacts the brake drum of the elevator brake, said sensor including a first connecting wire formed into a generally U-shape, loop and having an end connected to a first terminal, a second connecting wire formed into a generally U-shaped loop and having an end connected to a second terminal and a resistor means connected between said first and second terminals and in series with said connecting wires between said loops;
• and
• a monitoring circuit having an input and a plurality of outputs and wherein said first terminal of said sensor is electrically connected to said input of said monitoring circuit, whereby when said carrier is attached to the brake shoe with said sensor positioned adjacent the brake lining and said first terminal is connected to a source of electrical power, said sensor responds to conditions of the brake shoe representing normal operating capability of the brake lining, minimal thickness of the brake lining, brake lining fracture and excessive temperature in the brake lining by generating an associated one of a plurality of electrical signals to said monitoring circuit input, and said monitoring circuit responds to said electrical signals by generating a plurality of output signals at said outputs, each said output signal represent an associated one of the conditions of normal operating capability of the brake lining, minimal thickness of the brake lining, brake lining fracture and excessive temperature in the brake lining for the brake shoe.

An apparatus for monitoring an elevator brake, the elevator brake having a rotating brake drum which is braked and held by brake shoes with brake linings which linings are pressed into contact with an outside surface of the brake drum, the brake shoes being mounted on a brake mechanism which is responsive to an actuating device for moving the brake shoes to engage the brake linings with the brake drum with a braking and holding force, comprising:

• a carrier adapted to be attached to the brake shoe and extend into an area of the brake lining on the brake shoe;
• a sensor on said carrier, said sensor including a pair of connecting wires and a temperature dependent resistor, each said connecting wires being formed into a generally U-shaped loop extending toward the brake drum when said carrier is attached to the brake shoe, said temperature dependent resistor being electrically connected to an end of each of said connecting wires in series between said loops, another end of each of said connecting wires each being connected to an associated one of a pair of terminals;
• and
• a monitoring circuit having an input and a plurality of outputs, one of said terminals being electrically connected to said input of said monitoring circuit, whereby when said carrier is attached to the brake shoe and said one of said terminals is connected to a source of electrical power, said wires and said resistor respond to conditions of operating capability of the brake lining representing normal operating capability of the brake lining, minimal thickness of the brake lining, brake lining fracture and excessive temperature in the brake lining by generating an associated one of a plurality of electrical signals to said monitoring circuit input, and said monitoring circuit responds to said electrical signals by generating output signals at said outputs which output signals represent the conditions of normal operating capability of the brake lining, minimal thickness of the brake lining, brake lining fracture and excessive temperature in the brake lining for the brake shoe.