Abstract: An apparatus and method are provided for detecting brake drag of an elevator machine brake (30). Temperature sensors (44) are disposed in close proximity to a pair of brake pads (35,36) and compared to ambient temperature to determine whether the brake pads are dragging on a rotating brake drum (37). A comparison circuit (47) is used to determine if the temperature of the brake pads has exceeded a predetermined threshold level (55) and to produce an output signal (52) corresponding to the position of the brake pads.

Abstract: A bidirectional overspeed device is provided for an elevator system having an elevator car for travel within a hoistway along a guiderail. The elevator includes a governor rope running from a governor sheave at the top of the hoistway to a tension sheave at the bottom of the hoistway, and a bidirectional overspeed device. The bidirectional overspeed device comprises a bidirectional governor, a first safety brake, a second safety brake and a bidirectional linkage apparatus. In the event of an overspeed condition in either direction, the bidirectional governor clutches the governor rope, thereby operating the bidirectional linkage apparatus which connects the governor rope to the safety. Depending on the direction of the car travel, the linkage apparatus is either pulled upward or downward. Consequently, either the first or second safety is engaged and the elevator car is stopped.

Abstract: A muffler for attenuating pulsations within the hydraulic fluid of an hydraulic elevator includes a plurality of compressible elements for absorbing pressure pulsations within the fluid and a baffle for ensuring that the flow of fluid contacts the elements sufficiently to absorb such pulsations, the baffle allowing a certain amount of flow to pass therethrough so that the pressure drop around the baffle is not so extreme so as to cause the muffler to cease to function.

Abstract: Fluid is detected within a protective encasement of an hydraulic cylinder of an elevator by applying a low pressure to the interior of the encasement and sensing for the presence of fluid as a result of the application of the low pressure. If fluid is detected, a greater pressure is applied within the protective encasement to eliminate the detected fluid. The protective encasement, which may be pressurized, has a pressure input port, an evacuation port, and an evacuation tube which attaches to the fluid evacuation port and extends to a region within the encasement below the bottom of the cylinder.