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:
Sep. 20, 1977
Filed:
Apr. 30, 1976
Raymond L Chubb, Garland, TX (US);
Lawrence F Haven, Dallas, TX (US);
Robert W Hisey, Richardson, TX (US);
Gardner-Denver Company, Dallas, TX (US);
Abstract
A drive system for a hoist-pulldown linkage of a blast hole drill employs a variable speed electric motor and a variable ratio coupling between the motor and the hoist-pulldown linkage. A first regulator actuates the electric motor for high torque operation when the ratio of the coupling is low. A second regulator means activates the electric motor for low torque operation when the ratio of the coupling is high. Transfer in coupling ratio is coordinated with change between regulators. The first regulator means is a voltage regulator with a current spillover limit. The second regulator is a voltage regulator with an adjustable pulldown force limit with means to select the rotational speed reference of the motor.