Abstract: An elevator overspeed system designed to work as a governor includes a first switch responsive to an overspeed condition and a second, remotely located switch responsive to said first switch. An overspeed elevator control procedure is initiated when one of the first or second switches are tripped. The first switch is automatically re-set after the second switch is tripped. The second switch is manually re-set to re-start the elevator system in normal operation mode.

Abstract: An elevator car includes a hold closed feature for an elevator car door. The hold closed feature maintains the elevator car door in a hold closed position when the elevator car is not at a landing or is "parked" at a landing. The hold closed feature includes a profiled ramp disposed on the elevator car and a roller disposed on the elevator car door. The roller engages the profiled ramp during the hold closed position of the elevator car until a certain predetermined force is exerted for the roller to disengage from the profiled ramp.

Abstract: Magnetizing current generated in a linear induction motor driving elevator car doors in elevator systems is optimized. Magnetizing current level is set low for door operation modes requiring lower levels of thrust, such as hold open and hold closed. Magnetizing current level is increased for modes of door operation requiring greater thrust levels, such as closing or opening. Optimization of magnetizing current in linear induction motors reduces overheating and increases energy efficiency.

Abstract: A secondary positioning system for elevator car doors includes three sensors positioned in register with a plurality of openings formed within a door hanger. The unique spacing between the sensors in combination with unique spacing between each of the openings within the door hanger, allows determination of fully closed, fully opened, and intermediate positions and direction of elevator car doors.

Abstract: A method for generating velocity profiles for elevator car doors includes a step of generating a straight line velocity versus time profile. The profile is then passed through a low pass finite impulse response filter to smooth the transition between different velocity and acceleration values and to limit certain undesired frequencies. The filtered profile can be integrated into a position versus time profile and stored in the RAM of a control system to be used for subsequent operations.

Abstract: A method for scaling a position versus time profile for elevator car doors includes a step for generating a time scaling factor and a distance scaling factor. The scaling factors allow a previously stored position versus time profile to be used for all subsequent operations of the elevator car doors.

Abstract: A speed command signal is applied to a variable voltage, variable frequency controller for driving a three-phase induction motor that operates a positive displacement pump for supplying fluid to a hydraulic elevator drive cylinder. An accelerometer mounted on the car provides an acceleration-related feedback signal to the car speed command input of the motor control, thereby to dampen low frequency resonant modes of the elevator car. A sensor on a check valve between the hydraulic pump and the hydraulic cylinder provides a signal indicative of when the pump pressure is sufficient to support the car load, and the check valve begins to open; the signal is used to memorize ramped-up motor speed at that point, which equals the motor speed necessary to overcome pump leakage in order to support the car. That speed is added into the car speed command at the input of the motor controller to compensate for pump leakage.

Abstract: An apparatus and a method for reducing seal stiction is provided. In the method, a first step provides a fluid cylinder comprising a piston displacably mounted in a housing containing pressurized fluid is provided in the first step. The housing has first and second seals in register with the piston. In a second step, the second seal is applied to maintain pressure within the housing when the piston is in a static state. In a third step, the first seal is applied to maintain pressure within the housing and the second seal relaxed prior to displacement of the piston. In a fourth step, the second seal is applied to maintain pressure within the housing and the first seal relaxed subsequent to the displacement of the piston. An apparatus is provided for applying one of the first or second seals and relaxing the other of the first or second seals, before and after displacement of the piston.

Abstract: A hydraulic elevator pressure relief valve is activated if a pilot valve disposed therein senses an excessive pressure build up within a hydraulic elevator system. The pilot valve opens once excess fluid pressure force is detected. A main piston then facilitates communication between a solenoid valve disposed within the valving system and the drain pressure thereby closing a check valve and thus stopping an elevator car from further movement. The main piston further ports the excess fluid pressure force from the system to drain pressure, thus stabilizing the fluid pressure force therein.

Abstract: According to the invention, a valve for use with a variable speed motor and pump in an hydraulic elevator balances a fluid pressure force on a pump side of a control valve with a fluid pressure force on a cylinder side of the control valve before an elevator cab moves either upwardly or downwardly. On the pump side of the valve, a separate circuit, which is controlled by a solenoid, directs the pump fluid pressure force behind the valve until the sum of the fluid pressure acting on the pump side of the control valve overcomes the fluid pressure on the cylinder side of the control valve to open the valve.

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: The flow of hydraulic fluid to and from an hydraulic elevator piston is controlled by a motor-actuated spool valve operated by a microprocessor. To lower the elevator, a main check valve is opened by a down piston using hydraulic fluid from the system. Pressure is equalized on both sides of the main check valve just before the latter is opened thereby allowing the use of a smaller down piston which uses less hydraulic fluid. This results in smoother car motion during descent of the car. The addition of a valve bleed passage to equalize pressure on both sides of the check valve also prevents rapid descent of the elevator car in the event that the spool valve were to be open at the time descent commences.

Abstract: The flow of hydraulic fluid to and from an hydraulic elevator piston is controlled by a motor-actuated spool valve operated by a microprocessor. To lower the elevator, a main check valve is opened by a down piston using hydraulic fluid from the system. Pressure is equalized on both sides of the main check valve just before the latter is opened thereby allowing the use of a smaller down piston using less hydraulic fluid. This results in smoother car motion during descent of the car. The addition of a solenoid valve bleed passage to equalize pressure on both sides of the check valve also prevents rapid descent of the elevator car in the event that the spool valve were to be open at the time descent commences.

Abstract: A two-stage solenoid valve uses a pair of stacked coaxial armatures in a cylindrical sleeve housing. A first armature is provided with a fluid sealing ring and is urged by a first spring to peripherally seal an adjacent internal fluid port in a valve base supporting a first end of the sleeve housing. The first armature is provided with a coaxial bore extending through the armature and coaxial with the fluid sealing ring to form a fluid channel. The second armature also has a coaxial bore extending therethrough with a resilient sealing member slideably retained within the bore. A second spring is arranged to urge the resilient sealing member against a first end of the bore in the second armature and to extend therefrom to a fixed plug in a second end of the cylindrical housing. The resilient sealing member cooperates with a fluid port defining an end of the coaxial bore in the first armature opposite the end of the first armature having the fluid sealing surface.

Abstract: A three-way solenoid valve uses a movable armature housed in a coaxial sleeve and having longitudinal fluid channels on its outer surface and a fluid sealing element on both ends. A first fluid sealing element on a first end of the armature is a resilient ring arranged to cooperate with an adjacent fluid orifice in a valve body to peripherally seal the fluid orifice in response to spring pressure exerted by a spring acting on the first end of the armature in a first position of the armature during an deenergized state of the valve. The armature is provided with a coaxial longitudinal bore aligned with the center hole in the fluid sealing ring. During the deenergized state of the valve, a fluid path is provided between a first fluid port and second fluid port in the valve body via the hole in the sealing ring, the bore in the armature and the channels on the armature.