The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 22, 1996
Filed:
Sep. 12, 1995
Dale B Childress, Plainfield, IL (US);
Noah D Manring, Roland, IA (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
A pump displacement control for a variable displacement pump includes a torque control valve disposed between a variable torque limiter and a force applying device disposed in axial alignment within a common bore. A sleeve and a valve spool are movable relative to each other to establish a first condition communicating discharge pressure into an actuator chamber to move a swashplate toward a minimum displacement position against the bias of a spring or a second condition communicating the actuating chamber with an exhaust passage to allow the spring to move the swashplate toward its maximum displacement position. A torque control piston disposed between opposing springs resiliently bias the valve spool in a direction to establish the second condition when control fluid is directed into a control chamber. Pump discharge pressure communicated into a pressure chamber exerts a force against the valve spool proportional to the discharge pressure so that the valve spool moves in a second direction to establish the first condition when the control force exceeds the biasing force exerted by the torque limiter.