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:
May. 07, 1996
Filed:
May. 03, 1994
Michael J Mientus, Channahon, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
An accumulator charging valve has a first valve spool determining a cut-in pressure level at which fluid from a pump is directed to an accumulator and a second valve spool determining the cut-out pressure level at which fluid is no longer directed to the accumulator. When the pressure at the accumulator reaches a predetermined high level, the second valve spool moves to a position communicating an inlet port with an intermediate passage. The first spool is normally at a position blocking the intermediate passage from an outlet port so that a flow path is established through a pair of orifices reducing the pressure in the intermediate passage and the inlet port. The reduced pressure is transmitted to an actuating chamber to hold the second valve spool in the above noted position and to a pump displacement controller to destroke the pump to a low standby pressure displacement. When the pressure at the accumulator drops to a predetermined low level, the first valve spool moves to a position communicating the intermediate passage with the outlet port venting the actuating chamber so that the second valve spool moves to a position blocking the inlet port from the intermediate passage. This increases the pressure directed to the displacement controller upstroking the pump to a high pressure displacement. The cycle is repeated when the pressure reaches the predetermined high level.