Donald L Bianchetta

6477836, Nov 12, 2002

Oct 26, 2000

09/696853

Donald L. Bianchetta - Coal City IL
Bernard J. Wulff - Oswego IL
John V. Mount - East Peoria IL

Caterpillar Inc. - Peoria IL

F16D 3102

60422, 60442, 91461

A pilot control system for maintaining a constant operating hydraulic fluid pressure in a hydraulic system throughout a range of hydraulic fluid flow and temperature conditions. The pilot control system has a pilot pump and a pilot relief valve in fluid communication with the pilot pump. A first pressure reducing valve is in fluid communication with the pilot pump and the pilot relief valve so as to reduce the pressure to components downstream of the pressure reducing valve.

40066673, Feb 8, 1977

May 2, 1975

5/574229

Donald L. Bianchetta - Coal City IL
Kenneth R. Lohbauer - Joliet IL
Sammy J. Rhodes - Aurora IL

Caterpillar Tractor Co. - Peoria IL

F15B 1108
F15B 13042

91445

A load supporting hydraulic system having a pilot operated main control valve is provided with pilot controlled load check valve operative to permit free flow of fluid from said control valve toward the load supporting means of the system in response to pilot pressure and to block fluid flow from the load supporting means toward the control valve. The system includes vent valve means operative with the main control valve to permit the load check valve to be opened by fluid pressure in the load supporting means to allow fluid flow therefrom to the reservoir.

39876268, Oct 26, 1976

Jan 23, 1976

5/651889

Donald L. Bianchetta - Coal City IL

Caterpillar Tractor Co. - Peoria IL

F15B 1309
F16H 3946

60445

Fluid is selectively, controllably delivered at substantially common rates from separate respective variable displacement pumps in response to a load pressure signal acting on a single pump control valve serving said pumps.

39438252, Mar 16, 1976

Oct 26, 1973

5/409869

Donald L. Bianchetta - Coal City IL
Kenneth R. Lohbauer - Joliet IL
Sammy J. Rhodes - Aurora IL

Caterpillar Tractor Co. - Peoria IL

F15B 1108
F15B 13042

91438

A load supporting hydraulic system having a pilot operated main control valve is provided with pilot controlled load check valve operative to permit free flow of fluid from said control valve toward the load supporting means of the system in response to pilot pressure and to block fluid flow from the load supporting means toward the control valve. The system includes valve means operative independent of the main control valve to permit the load check valve to be opened by fluid pressure in the load supporting means to allow fluid flow therefrom to the reservoir. The system further includes safety valve means for blocking fluid flow to pilot control means.

54718376, Dec 5, 1995

Sep 3, 1993

8/115621

Donald L. Bianchetta - Coal City IL

Caterpillar Inc. - Peoria IL

F16D 3900

60426

A hydraulic control system is designed to permit the use of a plurality of small substantially identical existing valve assemblies in place of a lesser number of larger valve assemblies. In one embodiment, a first pair of variable displacement load sensing hydraulic pumps communicate with a manifold connected to a first valve assembly and another pair of variable displacement load sensing hydraulic pump communicate with a second manifold connected to second and third valve assemblies. A crossover conduit interconnects the manifolds so that fluid from all four pumps can be used by any one of the valve assemblies or shared by two or all three of the valve assemblies. In another embodiment, a third pair of variable displacement load sensing hydraulic pumps communicate with the first manifold 12 which also has another valve assembly connected thereto. Also in this embodiment, two crossover conduits interconnect the manifolds so that the fluid from all six pumps can be used by any one of the valve assemblies or shared by two or more of the valve assemblies.

43555659, Oct 26, 1982

Mar 24, 1980

6/206192

Donald L. Bianchetta - Coal City IL

Caterpillar Tractor Co. - Peoria IL

F15B 1116

91518

A load check valve is normally employed in association with a double-acting hydraulic cylinder, such as the type used to raise and lower the boom of a construction vehicle. Conventional check valves of the poppet type are difficult to modulate whereas check valves of the spool type generally do not insure leakage control at an acceptable rate during normal operation. The spool-type load check valve (20) of this invention, used in conjunction with additional check valves (60,61), overcomes the latter problem by providing a series of interconnecting passages and chambers (36) for communicating equalized fluid pressure from a cylinder (11) to either end of the spool (27) thereof to provide for minimal leakage. When a pair of such cylinders (11,12) are utilized, the load check valves (20,20') associated therewith are interconnected by a balance line (50) and resolver valves (47') to insure equalization of fluid pressure in the cylinders upon actuation thereof and to further insure a gradual descent of a load carried by the cylinders upon loss of fluid pressure between the check valves.

50779729, Jan 7, 1992

Jul 3, 1990

7/548341

Donald L. Bianchetta - Coal City IL
Gene R. St. Germain - Plainfield IL

Caterpillar Inc. - Peoria IL

F16D 3102

60427

Load sensing hydraulic systems are useful for distributing fluid from a variable displacement pump to the individual work circuits in accordance with the demand of each work circuit. Preventing load pressure from being drained from the motors of the work circuits during some operating functions heretofore required the use of a pair of pressure compensating valves and a pair of shuttle valves at each of the directional control valves. The subject load pressure duplicating circuit includes a single load pressure duplicating valve having an end subjected to the load pressure in a signal network and reduces pump pressure entering the valve to a pressure level at the output thereof equal to the load pressure. This duplicated pressure is then utilized as the control fluid for the pressure compensating valves and a displacement controller of the pump. The system is greatly simplified by the use of only a single duplicating valve for a hydraulic system having a plurality of work circuits.

42300223, Oct 28, 1980

Jan 8, 1979

6/001492

Donald L. Bianchetta - Coal City IL
Lawrence F. Schexnayder - Joliet IL

Caterpillar Tractor Co. - Peoria IL

F15B 1116

91516

A hydraulic control system having a pump and circuits connecting the pump to a pair of hydraulic motors through first and second circuits is provided with a priority valve system operative to provide a priority of fluid pressure to the first motor up to a predetermined minimum pressure and thereafter to maintain the pressure in the first circuit and simultaneously supply fluid to the second motor of the second circuit. The priority valve system is also responsive to a load on a second motor to split the flow of fluid between the two motors above the predetermined minimum pressure up to a second pressure after which the second predetermined pressure is maintained in the first circuit while fluid is being supplied to the second conduit.