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. 17, 2001
Filed:
Sep. 24, 1999
Roger Mickelson, West Burlington, IA (US);
Richard J. Lech, Burlington, IA (US);
Case Corporation, Racine, WI (US);
Abstract
A construction machine, e.g., a backhoe, has a chassis and a digging tool mounted for movement, e.g., swinging movement, with respect to such chassis. A machine hydraulic circuit includes a pump, a hydraulic actuator coupled to the tool for tool movement, and a directional valve between the pump and the actuator. In several specific embodiments, the circuit includes first and second flow restrictors coupled between the pump and the actuator. There is also a valve device for selectively disabling the second flow restrictor, thereby configuring the circuit to provide either of two maximum rates of tool movement. In other embodiments, the circuit uses a variable delivery, fluid-pumping power source and a load-sensing line coupled between the pump and the actuator. The valve device is in series with the load-sensing line and includes a restriction-free path and a flow-restricted path therethrough, thereby configuring the circuit to provide either of two maximum rates of tool movement.