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:
Jun. 01, 1976
Filed:
Apr. 07, 1975
Emerl R Carpenter, Edina, MN (US);
American Hoist & Derrick Company, St. Paul, MN (US);
Abstract
A hydraulic backhoe utilizes two pairs of hydraulic pumps to power independent crawler track drives in any forward or reverse direction, and high or low speed ranges; allowing, for example, a wide arc turn either left or right, forward or backward. Through a novel hydraulic circuit, these pumps also power other functions such as boom, bucket and stick drives in high speed or low speed modes. This flexibility is accomplished by the use of a manually controlled track speed selector valve, an unloading valve and check valve between a track function valve and another function valve in each of the two hydraulic circuits. Full hydraulic pressure is available to all functions at all times except when a track drive is in high speed range. Conventional high-low or unloading operation of the other functions is had when the related track drive is not operating.