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. 21, 1992
Filed:
Jan. 22, 1991
Clarence L Bandy, Jr, Glade Spring, VA (US);
American Longwall Mining Corporation, Abingdon, VA (US);
Abstract
A conveyor assembly includes an endless conveyor having ends supported by a drive drum/sprocket and an idler drum/sprocket mounted on respective portions of a split conveyor frame. The frame portions are movable with respect to each other. Dual tensioning cylinders control the movement of the portions and thus the tensioning force acting on the conveyor. A hydraulic circuit for the tensioning cylinders provides a first level of tensioning force to said conveyor upon initial start-up of the conveyor apparatus and a second reduced level of tensioning force after a predetermined time. The first level of tensioning force is sufficient to overcome the breakaway friction between the frame portions while the second level of tensioning force is sufficient for proper and sustained tension during normal operation of the conveyor. A time delay control valve in the circuit includes a movable valve element actuable by a differential hydraulic force through a combination of restrictive orifices, an accumulator, a return spring and operating faces.