Chester L Wilson

47505893, Jun 14, 1988

Jun 8, 1987

7/059623

Chester K. Wilson - Manchester MO

B66B 104

187 292

An elevator leveling control for a system described in U. S. Pat. No. 3,056,469, includes a leveling cylinder and piston arrangement responding to less pressure than the main control cylinder and piston, so that during the operation of the main cylinder and piston, the leveling piston is always in its uppermost position, and a leveling cam, carried by the leveling cylinder-piston arrangement produces the minimum resistance in a rheostat electrically connected to the control field of a generator supplying power to the elevator motor. Through the travel of the elevator in high speed, the leveling rheostat is disconnected from the control field and the main rheostat is connected. At a given distance from the floor at which the elevator is to stop, a valve in the hydraulic system is energized to close, holding the main rheostat from dropping farther, the main rheostat is disconnected and the leveling rheostat is electrically connected to the generator control field. The leveling cam then acts to increase the resistance in the control field of the generator to bring the car smoothly and accurately to its rest position.

46870784, Aug 18, 1987

Jun 23, 1986

6/877157

Chester K. Wilson - Manchester MO

B66B 1104

187 17

In a hydraulic elevator system including a hydraulic cylinder, ram mounted in the cylinder and supporting an elevator car, a reservoir of hydraulic fluid and a return line connected to communicate with hydraulic fluid in the cylinder and the reservoir to permit the fluid to exhaust from the cylinder to the reservoir, a control valve assembly has an exhaust orifice communicating with the fluid in the hydraulic cylinder and with the reservoir, an exhaust piston for selectively closing and opening the orifice and a device responsive to pressure of the hydraulic fluid for limiting the amount by which the exhaust piston opens the orifice.