Abstract: A control for oil flow in a hydraulic system wherein a standard open closed type solenoid valve is modified so that the rate of flow through the valve relates to the electrical power supplied to the valve solenoid coil.

Abstract: A drive control system for an hydraulic elevator that reduces the time delay between the starting of an hydraulic pump in the system, and the first upward movement of the elevator.

Abstract: A clamping system for selectively keeping a hydraulic elevator stationary at a selected floor level.

Abstract: A hydraulic elevator up direction control system is provided that has a circulating valve connected between the supply and the return of a source that normally supplies pressure to the cylinder of an elevator. The circulating valve is controlled by a computer regulated stepless variable solenoid valve that influences the pilot fluid pressure in the operating chamber of the circulation valve to control the size of the opening of the circulating valve and thereby the volume of fluid passing through the circulating valve. This affects inversely the volume of fluid passing through a fluid flow measuring valve, to the cylinder, to provide selectably variable up speeds of travel facilitating a fast, smooth, accurate ride of the elevator car as it approaches a stopping point relative to an upper floor of a building. Such operation is substantially independent of the system pressure and fluid viscosity. A selectably variable speed down direction control system operates on largely the same principle.

Abstract: An up leveling control system for small elevators that uses an adjuster having a small orifice coordinating with an up speed metering edge of a separate spool in the form of a taper to meter the rate of flow of pilot oil from a bypass chamber to control the position of a bypass valve and thereby regulate the volume of oil flow proportionately to the elevator cylinder and to the pump reservoir.

Abstract: A hydraulic elevator up direction control system is provided including a circulating valve connected between the supply and the return of a source that normally supplies pressure to the cylinder of an elevator controlled by a two position switchable setting valve that influences the pilot fluid pressure in the operating chamber of the circulating valve to control the size of opening of the circulating valve and thereby the volume of fluid passing through the circulating valve affecting inversely the volume of fluid passing through a check valve, to provide two distinctive intermediate up speeds of travel in addition to the nominal full speed of travel facilitating a fast, smooth and accurate ride of the elevator car as it approaches a stopping point relative to an upper floor of a building. A three speed down direction control system presents no problems of significance and is not dealt with.

Abstract: An hydraulic elevator control system is provided including a by-pass valve connected between the supply and return of a source that normally supplies pressure fluid to the cylinder of the elevator and a setting valve that is operable by fluid supplied from the operating chamber of the by-pass valve to control the operation of the check valve, thereby to achieve a creeping speed of travel of the elevator car as it approaches a stopping point relative to the floor of a building to compensate for variation in oil temperature and/or pressure that occur through increased loading of the elevator, there is mixed with the primary flow of fluid to the setting valve a secondary flow of pressure--and viscosity--responsive fluid that flows over a long-edged restrictor device.

Abstract: A down valve (1) consists of a sealing spool device (6) which in its closed position separates a pressure chamber (3), which is connected with the elevator hydraulic cylinder (9), from a return flow chamber (5). The sealing spool device (6) includes a sealing plug (32) which seals off the two chambers (3 and 5) and a metering plug (33) which is intended for the connecting of the two chambers (3 and 5). The return flow orifices (51) are governed by a control edge (57). The metering plug (33) is influenced toward a given position relative to the sealing spool (6) by pressure in a positioning chamber (44) against the force of a compensating spring (56) such that the return flow orifices (51) are choked down. The operating pressure present in the pressure chamber (3) is fed through the pressure sensing orifice (46) to the positioning chamber (44).

Abstract: A hydraulic elevator up direction control system is provided that has a circulating valve connected between the supply and the return of a source that normally supplies pressure to the cylinder of an elevator. The circulating valve is controlled by a computer regulated stepless variable solenoid valve that influences the pilot fluid pressure in the operating chamber of the circulation valve to control the size of the opening of the circulating valve and thereby the volume of fluid passing through the circulating valve. This affects inversely the volume of fluid passing through a fluid flow measuring valve, to the cylinder, to provide selectably variable up speeds of travel facilitating a fast, smooth, accurate ride of the elevator car as it approaches a stopping point relative to an upper floor of a building. Such operation is substantially independent of the system pressure and fluid viscosity. A selectably variable speed down direction control system operates on largely the same principle.