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. 14, 2000
Filed:
Sep. 03, 1998
Michael Hung, Tao Yuan County, TW;
Other;
Abstract
The invention relates to an improved hydraulic quick lifting unit used in a jack, especially to improvements made on the valves of the hydraulic system, a fastener assembly and an oil return tube of the lifting shaft. The hydraulic system can return hydraulic liquid to the outer oil reservoir in a slow rate when the lifting shaft according to the invention bears a load. Thus the lifting shaft moves down slowly. When the load on the lifting shaft is removed, the hydraulic liquid flows back to the outer oil reservoir in a larger quantity in a short time. Hence the lifting shaft can quickly return to the its original position. Further, the fastener assembly is located between the lifting shaft and the mandrel, which has the advantages of enhancing the accuracy of the clearance between the mandrel and the inner oil reservoir of the lifting shaft, and preventing the positional shift of the mandrel in the inner oil reservoir. The invention has the benefit of enhancing the stability of product performance.