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:
Jul. 30, 2013
Filed:
Nov. 21, 2007
Bruce E. Knuth, Marshall, WI (US);
Kay Lap Gilbert Chan, Madison, WI (US);
Theo H. H. Den Ridder, Oosterhout, NL;
Frantz D. Stanford, Monona, WI (US);
Roger R. Pili, Madison, WI (US);
Bruce E. Knuth, Marshall, WI (US);
Kay Lap Gilbert Chan, Madison, WI (US);
Theo H. H. Den Ridder, Oosterhout, NL;
Frantz D. Stanford, Monona, WI (US);
Roger R. Pili, Madison, WI (US);
Actuant Corporation, Mchomonee Falls, WI (US);
Abstract
A rotary air motor driven hydraulic pump has separate pressure and return actuators and first and second stage eccentric driven pistons 180 degrees out of phase and driven by the motor through a gear reduction unit. The pressure and return actuators are on/off/proportional valves and the pump has two pressure relief valves with one adjustable from outside of the pump for a user to set a pressure limit of the pump. Above a certain output pressure limit, a bypass valve shunts flow in excess of that needed to precharge the second stage compression chamber from the first stage piston to an elastic reservoir from which the hydraulic fluid pumped by the pump is drawn. To make the pump stall at a certain output pressure, a pressure limiting valve can be used that cuts off the air supply to the pump at the desired output pressure.