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:
Aug. 13, 1991
Filed:
Feb. 05, 1990
Lars K Larsson, Sandviken, SE;
Sven P Liljebrand, Sandviken, SE;
Sandvik AB, Sandviken, SE;
Abstract
A drill string for top hammer drilling includes a drill bit, a set of central rod members for transferring impact energy to the drill bit, and a set of tubular members surrounding the rod members for transferring rotation to the drill bit. The rod members define a first internal channel for conducting flushing medium. The drill bit defines a second internal channel which extends rearwardly and penetrates a rear end of the drill bit to communicate with the first channel. The drill bit further includes a transverse channel disposed in an intermediate section of the drill bit and which is connected to the second channel. The transverse channel penetrates an envelope surface of the drill bit for conducting flushing medium out of the drill bit and into an enlarged space defined between the drill bit and the tubular member. Flushing medium discharged through the transverse channel supplies lubricant to a splined connection between the drill bit and the tubular member, and equalizes pressure between the second internal channel and the space between the drill bit and the tubular member.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile