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:
Sep. 19, 1978
Filed:
Oct. 15, 1976
Howard L Johnson, Joliet, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A construction vehicle has a work implement, such as a bucket-carrying boom, pivotally mounted thereon to be raised and lowered by one or more double-acting hydraulic cylinders. A directional control valve is conditioned to selectively communicate pressurized fluid to the rod end of each cylinder, for example, through a check valve. When the fluid pressure in the rod end of the cylinder exceeds a predetermined level, a pilot signal will be communicated to a modulating valve which will open to closely control and modulate the flow of the fluid exhausted from the head end of the cylinder. A pilot relief valve is interconnected between the head end of the cylinder and the modulating valve to cooperate therewith to relieve excessive fluid pressures. The above system is duplicated for selectively pressurizing the head end of the cylinder and for exhausting the rod end thereof.