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:
Jan. 29, 2013
Filed:
Mar. 09, 2010
J. Dewayne Allen, Paragould, AR (US);
Timmy D. Guinn, Paragould, AR (US);
Edward A. Waldon, Paragould, AR (US);
Scott R. Sugg, Paragould, AR (US);
J. Dewayne Allen, Paragould, AR (US);
Timmy D. Guinn, Paragould, AR (US);
Edward A. Waldon, Paragould, AR (US);
Scott R. Sugg, Paragould, AR (US);
Allen Engineering Corporation, Paragould, AR (US);
Abstract
High performance, multiple rotor, hydraulically driven riding trowels for finishing concrete have unloader valve circuitry for controlling hydraulic pressure. Each trowel has a rigid frame with two or more downwardly-projecting, bladed rotor assemblies that finish concrete. The rotor assemblies are tilted manually or hydraulically to effectuate steering and control. Blade pitch is controlled manually or hydraulically. The unloader valve system monitors drive pump pressure with a shuttle valve to derive an unloader pilot signal. A sequence valve responds to the unloader pilot signal to control a pressure valve that bypasses the normal foot control valve in an overpressure situation. The pressure control head signal normally applied to the hydraulic drive motor control heads is modified with a feedback signal to automatically control the associated pump swash plates. A gearbox may be disposed between the drive motors and rotors. Piston type and gear and vane type motors may power the rotors.