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:
Apr. 15, 1986
Filed:
Sep. 27, 1983
Pekka Salmi, Tampere, FI;
Timo Muttonen, Nokia, FI;
Oy Tampella AB, Tampere, FI;
Abstract
A pressure-medium driven percussion device including a body, a drill shank gliding axially in the body for transmitting percussions to a drill rod and a percussion piston moving in the body for directing percussions axially to the drill shank. The drill shank includes a lifting piston which moves in a lifting cylinder within the body. The body further includes a channel passing to the lifting cylinder for supplying and removing pressure medium into and out of the lifting cylinder and seals located between the body and the drill shank at both sides of the lifting cylinder. An equalizing channel is located between each seal and a corresponding choking slot. A valve connects the equalizing channels to the source of pressure medium when a channel passing to lifting cylinder is connected to a pressure medium container, and, correspondingly, to the pressure medium container when the channel passing to the lifting cylinder is connected to the source of pressure.