Patent ID: 8141655
Filing Date: 2012-03-27
Classification: B23B,B25D,Y10T

Abstract:
1. A hammer comprising: a housing including an upper housing member and a lower housing member, the housing defining a chamber, the upper housing member having a first pressure source of pressurized hydraulic fluid or pressurized air; a piston reciprocating inside the chamber, the piston including at least a first surface which communicates with the first pressure source to move the piston in a first direction; a reciprocating work tool residing at least partially inside of the chamber, an upper part of the work tool being struck by the piston as the piston moves in the first direction inside the chamber to transfer force from the piston to a tip of the work tool, the tip being formed opposite the upper part and residing outside of the chamber, the upper part of the work tool being housed inside the lower housing member; a tool retention member removably attached to the lower housing member, wherein when the tool retention member is attached to the lower housing member the work tool cannot be removed from the chamber and when the tool retention member is removed from the lower housing member, the work tool may be removed from the chamber for replacement; a socket portion formed on one of the upper housing member or the lower housing member, a plug portion formed on the other of the upper housing member or the lower housing member, the plug portion positioned in the socket portion, a plurality of outwardly projecting lugs formed on the plug portion and a plurality of inwardly projecting projections formed on the socket portion, the lugs being passable between the projections when the upper housing member is attached to the lower housing portion by inserting the plug portion into the socket portion, then rotatable relative to the projections to engage the lugs beneath the projections and prevent removal of the plug portion from the socket portion; and a prestressing structure configured to urge surfaces on the lugs and the projections into compressive engagement with one another, the prestressing structure including at least one jacking screw positioned between the upper housing member and the lower housing member.