David M Nies, 5540 Vinway Ct APT 2, Dayton, OH 45415

5535590, Jul 16, 1996

Apr 6, 1995

8/417556

David L. Nies - Beavercreek OH

General Motors Corporation - Detroit MI

B60T 1126
B60T 1128

60588

A brake master cylinder includes a shiftable seal that provides an apparatus for maximizing compensation fluid flow during minimal fluid draw conditions such as occur through automatic traction control brake intervention type operation. The shiftable seal moves forward to compress a low load spring during fluid draw from the master cylinder's high pressure chamber to open a compensation flow path between the seal and the piston.

5328178, Jul 12, 1994

Oct 14, 1992

7/960643

David L. Nies - Beavercreek OH

General Motors Corporation - Detroit MI

F16J 1532

277205

A ring seal for sealing a piston of a master cylinder is provided. The ring seal is fitted within a generally rectangular groove of the piston, the groove having front and rear walls joined by a floor. The ring seal prevents fluid communication from a first chamber to a second chamber during high pressure differentials and allows fluid communication from the second chamber to the first chamber under very low pressure differentials.

4886319, Dec 12, 1989

Nov 30, 1988

7/277804

David L. Nies - Dayton OH
Tomas L. Shroyer - Centerville OH

General Motors Corporation - Detroit MI

B60T 1300
B60T 826

303 975

The present invention provides an apparatus and method of utilization thereof of a vehicle brake master cylinder proportioning valve. The valve includes a valve body having a main bore fluidly connected with the master cylinder, primary and secondary circuits. A first housing fluidly seals the main bore into first and second chambers. A second housing fluidly separates the main bore second chamber from the secondary circuit. A valve piston spring biased away from the first chamber is mounted within a bore of the housing. The valve also has fluid communication between the second circuit and second chamber when the fluid pressure within the second circuit exceeds the fluid pressure within the second chamber. At an increase in master cylinder pressure past a first predetermined pressure the valve piston moves towards the first chamber, reaching a pressure balanced position metering pressurized fluid flow from the master cylinder to the second circuit. A lowering of the master cylinder pressure causes the piston to move towards the first chamber displacing fluid away from the second circuit and thereupon the valve piston is returned by the spring to a position furtherest away from the first chamber.