Resumes
Resumes
Walter Marietta Phones & Addresses
-
Mentor, OH
Publications
Us Patents
Hydraulic System And Control Valve Assembly Therefor
View pageUS Patent:
40220222, May 10, 1977
Filed:
Apr 26, 1976
Appl. No.:
5/680534
Inventors:
Walter Edwin Marietta - Mentor OH
Assignee:
Parker-Hannifin Corporation - Cleveland OH
International Classification:
F16H 3946
F15B 1116
F15B 1116
US Classification:
60433
Abstract:
A hydraulic system and control valve assembly therefor characterized in that it provides a two wheel pressure compensated hydraulic drive for mobile equipment in forward or rearward direction at any speed up to maximum as determined by the operation of the control valve assembly. Said control valve assembly is further characterized in that it incorporates an override for the pressure compensating means to achieve steering control by decreasing the rate of flow of fluid to either wheel motor or to achieve braking action in conjunction with a counterbalance valve in the motor return circuit by decreasing the rate of flow of fluid to both wheel motors.
Horsepower Summation Control For Variable Displacement
View pageUS Patent:
41628748, Jul 31, 1979
Filed:
Nov 7, 1977
Appl. No.:
5/848786
Inventors:
Walter E. Marietta - Mentor OH
Assignee:
Parker-Hannifin Corporation - Cleveland OH
International Classification:
F04B 4900
US Classification:
417216
Abstract:
Two variable displacement pumps each having a horsepower (or torque) control valve, a pressure limiting valve, and a displacement feedback valve are interconnected to provide fluid flow paths from the high pressure zone of one pump to the low pressure zone of the other pump via the horsepower control valve and the displacement feedback valve of the respective pumps and vice versa. When one pump is utilizing less than one-half of the available engine torque as at deadhead operation or low displacement operation wherein its pressure limiting valve determines the maximum delivery pressure or wherein the pump is in standby operation, its displacement feedback valve will correspondingly increase the back pressure of the horsepower control valve of the other pump so that the latter may utilize the torque deficiency of the former to bring the total torque utilization of both pumps to the engine torque limit.
Variable Displacement Pump Control Assembly
View pageUS Patent:
39457648, Mar 23, 1976
Filed:
Sep 5, 1974
Appl. No.:
5/503249
Inventors:
Walter E. Marietta - Mentor OH
Assignee:
Parker-Hannifin Corporation - Cleveland OH
International Classification:
F04B 126
US Classification:
417212
Abstract:
A variable displacement pump control assembly as for an axial piston pump having a swash plate actuating piston characterized in that the control assembly is embodied in the pump housing to provide a pressure compensated pump, or to provide a pressure compensated pump having an auxiliary modulator to control the pressure applied to the swash plate actuating piston to maintain a predetermined pressure drop across a variable area metering orifice embodied as in a directional control valve for a fluid motor, or to provide a pressure compensated pump having a horsepower modulator with or without the auxiliary modulator, said horsepower modulator providing desired control of horsepower in relation to pump delivery pressure and displacement.
Variable Displacement Pump With Torque Limiting Control
View pageUS Patent:
43325319, Jun 1, 1982
Filed:
Jan 28, 1980
Appl. No.:
6/116330
Inventors:
Walter E. Marietta - Mentor OH
Assignee:
Parker-Hannifin Corporation - Cleveland OH
International Classification:
F04B 4900
US Classification:
417218
Abstract:
A variable displacement pump 1 includes a housing 2 having an inlet port 3 and an outlet port 4. The pump 1 is an axial piston pump having a swash plate 5 which is actuated to different angular positions by an actuating member 7. The torque limit of the pump 1 is controlled by a horsepower control valve 19 and a speed responsive control valve 35, which change the torque limit of the pump 1 in response to changes in the position of the actuating member 7 and in response to changes in the speed of the engine 33. In this manner, the torque limit of the pump 1 for any position of the actuating member 7 closely approximates the maximum available output torque of the engine 33.