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:
Dec. 27, 1994
Filed:
Mar. 12, 1993
Mitsuhiro Kishi, Ashikaga, JP;
Japanic Corporation, Tochigi, JP;
Abstract
A stretchable arm of a deep excavator comprises top, middle and base arms wherein a bucket is suspended from the top arm and a working unit is fixed to the middle arm. Two hydraulic cylinders constituting the working unit are arranged in parallel with each other while cylinder rods thereof are oppositely directed, wherein the cylinder rod of one hydraulic cylinder is coupled to the base arm and the cylinder rod of the other hydraulic cylinder is coupled to the top arm. It is possible to extend and contract each arm of the stretchable arm synchronously with one another at higher speed compared with a conventional deep excavator having a single hydraulic cylinder. The oil under pressure which flows out from the discharge chamber of each hydraulic cylinder can be merged into the oil under pressure for extending each hydraulic cylinder so that the amount of oil to be supplied to the pressure chamber is increased.