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:
Feb. 25, 2003
Filed:
Nov. 02, 1999
Robert James Johnston, Oskaloosa, IA (US);
Thomas Daryl Bebernes, Ottumwa, IA (US);
Deere & Company, Moline, IL (US);
Abstract
A vehicle has a pair of opposite drive wheels driven by a dual path hydrostatic transmission. Steering and speed/direction controls are effected by changing the displacement and/or direction of fluid flow through the pair of reversible, variable displacement pumps that are respectively coupled to fixed displacement ground wheel drive motors. The control mechanism for accomplishing steering and/or speed/direction control includes a steering rack that is caused to pivot about a fixed post in response to steering wheel movement. A first crank arm is coupled for pivoting in concert with the rack and a second crank arm is coupled for pivoting in concert with a pivot plate about a second axis, the pivot plate having a pair of connection points respectively coupled to control arms of the pair of pumps by a pair of pump control rods. The pivotal motion of the steering rack is transmitted to the pivot plate by a tie-rod coupled between the first and second crank arms. This tie-rod is parallel to a pivot support bar that swings about the fixed post in response to fore-and-aft movement of a speed/direction control lever, the pivot plate being pivotally mounted to the free end of the pivot support bar. Thus, the pivot support bar, first and second crank arms and the tie-rod cooperate to define a four-bar linkage that causes the pivot plate to retain its pivoted position about the second axis during speed/direction control so that such control is made independently of steering, and vice-versa.