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:
Jul. 19, 1988
Filed:
Aug. 24, 1987
Jerry J Burckhartzmeyer, Peoria, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
Backhoes are useful for digging trenches, ditches, etc. However, a performance deficiency caused by the formation of voids in the hydraulic control motor occurs sometimes if the swinging mass of the backhoe is abruptly stopped by quickly moving the directional control valve to the neutral position. The present invention provides a control circuit having a charging valve for communicating pressurized fluid from the supply conduit connected to the pump to charge the makeup valves with pump discharge fluid to minimize or avoid the formation of voids when the directional control valve is moved to the neutral position to stop the swinging movement of the backhoe mechanism.