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:
Mar. 07, 1978
Filed:
Apr. 02, 1976
Leon A Wirt, Joliet, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
In a tree harvesting machine having a shear assembly, a delimbing assembly, a drive mechanism for moving a tree past the delimbing assembly, and a grapple arm for urging the tree into engagement with the drive mechanism and the delimbing assembly, a hydraulic control circuit including a pair of control valves disposed along a main fluid line providing communication between an upstream source of fluid under pressure and a downstream reservoir, one of the valves being selectively operable to divert fluid under pressure upstream to a grapple arm motor and simultaneously provide communication between the grapple arm motor and the line downstream to actuate or retract the grapple arm, and the other of the valves being selectively operable to divert fluid under pressure upstream to a shear motor and simultaneously provide communication between the shear motor and the line downstream to actuate or retract the shear assembly and to divert fluid under pressure upstream to a drive motor to actuate the drive mechanism when the shear assembly is retracted. Preferably, an accumulator is connected to the grapple arm motor to maintain grapple arm pressure and a pressure relief valve is disposed between the source of fluid under pressure and the control valves to assist in properly operating the tree harvesting machine.