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. 11, 1989
Filed:
Sep. 03, 1987
George A Parrott, Wakefield, GB;
Minnovation Limited, Wakefield, GB;
Abstract
A gearbox for a rotary, mineral cutting head, comprises a casing housing speed reduction gearing and also a portion of a drive shaft supported by first and second, spaced-apart bearings, with at least one radially extending cylinder having a closed inner end and an open, outer end provided in said drive shaft and a reciprocable piston partially housed in said cylinder with a fluid seal between said piston and said cylinder; a variable volume, pressure-generating chamber defined between a radially inner end of said piston and a closed, inner end of its cylinder; a ring surrounding said drive shaft and having an inner profile and with a radially outer end of said piston in contact with said inner profile and with said piston.