Abstract: A linear motor is used to actuate an elevator door in response to a control signal for counteracting rotational torque caused by a variable-length moment arm about the center of gravity of the door by varying the magnitude of a linear force exerted on the door acting through a fixed-length moment arm about the center of gravity of the door for providing an opposing rotational torque, thereby counteracting the rotational torque caused by the normal force. The first and second rotational torques may be controlled to decrease and increase linearly as the door goes through its motion. In this way, the velocity profile varies in a curve similar to one side of the major axis of an ellipse. The normal force may be provided so as to levitate the door to reduce gravitational forces acting on door rollers. The control may be carried out in an open- or closed-loop fashion.

Abstract: An adjustable elevator rail repair device (14) is provided with a means for forcing raised damaged areas (18) of an elevator rail (10) back into the corresponding depressions (20) of the rail surface (9). The forcing means comprises a roller (24) rotatably mounted within a wedge (22), adjustably positioned in a housing (16). A method is disclosed for repairing the damaged rail (10) comprising a calculating step to determine the amount of adjustment necessary for the rail repair device (14).

Abstract: An elevator hydraulic tank is provided with shaped sides which increase the rigidity and heat dissipating ability of the tank. The shaped sides of the tank may be corrugated. A hydraulic machine is mounted on the underside of the tank lid so that maintenance of the machine does not require draining of the tank. The shaped sides are enclosed by an outer shell which further minimizes noise emanating from the tank.

Abstract: A lightweight, prefabricated elevator cab is provided having a wall structure with a plurality of panel sections connected to one another by hinge seams. The integrally attached hinge seams and the panel sections are formed from the same homogeneous material. The hinge seams are capable of being elastically deformed.

Abstract: A retainer assembly is provided having a clasp section and at least one collar. The clasp section has an axially extending aperture and cutout section. The cutout section, which exposes the aperture, allows the member of a stiffening assembly to pass through to and be received by the aperture. Once received by the aperture, the member is fixed within the aperture of the clasp section by the collar.

Abstract: A mechanism is placed between a plunger and an elevator car to damp the effects of stick-slip encountered during elevator start-up and to minimize the probability of damage to a plunger/cylinder assembly if the elevator car is stopped in an emergency. The mechanism comprises a self-leveling hydraulic shock absorber that operates independently of any stick-slip between the plunger and cylinder.

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.

Abstract: The cable drive sheave (14) carries a wedge-shaped brake ring (44) engageable with V-shaped brake shoes (52, 58). Each shoe is spring biased (68, 76) tangentially toward the ring and resiliently supported and biased radially (50) toward the ring. The shoes are restrained (84) during normal elevator operation and released on either cab upward overspeed (22) or on cab movement from a landing with the doors open (32).

Abstract: A hydraulic elevator buffer contains a piston (plunger) which is pushed down into a volume of hydraulic fluid. The buffer has no seals separating its interior from the atmosphere. As the piston is pushed down, the displaced fluid is forced through ports in the cylinder which gives rise to a restricting force. The displaced fluid escapes into a volume in which an air/fluid mixture is produced. A nozzle area surrounds the piston at the top of the container, and the mixture is forced through the nozzle, separating the fluid and air. The fluid condenses down, lubricating the piston. The air is forced out through the space between the fluid container and the piston, removing any contaminants around the piston. The buffer contains a fluid-fill port which is at a horizontal angle at which a minimum and maximum fluid level in the buffer can be determined by looking in the port.