Hammer having a two part body

Abstract

A tool assembly such as a hammer assembly, includes a housing defining a chamber and a reciprocating piston arranged in the chamber for cyclical movement in a work stroke and a return stroke. The housing includes a lower housing member, an upper housing member and an engaging structure which permits the engagement of the upper housing member with the lower housing member by relative rotation of the upper and lower housing members, such that each of the lower and upper housing members defines a portion of the chamber. The upper housing member is a precision component which contains the hydraulic components or other drive components necessary to drive the piston, while the lower housing member can be manufactured separately since it does not need to be manufactured to the high tolerances required by the upper housing member. The resulting tool assembly may be more compact than a conventional tie rod tool assembly.

1 . A method comprising:
 attaching an upper housing member to a lower housing member to form a housing, the housing including a chamber extending between the upper housing member and the lower housing member, the upper housing member having a first pressure source of pressurized hydraulic fluid or pressurized air;   positioning a piston inside the chamber for reciprocal movement therein, the piston including at least a first surface which communicates with the first pressure source to move the piston in a first direction; and   positioning a reciprocating work tool 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, wherein   attaching the upper housing member to the lower housing member further comprises engaging a socket portion formed on one of the upper housing member or the lower housing member with a plug portion formed on the other of the upper housing member or the lower housing member, by inserting a plurality of outwardly projecting lugs formed on the plug portion into the socket and between a plurality of inwardly projecting projections formed on the socket portion, then rotating the lugs relative to the projections to engage the lugs beneath the projections and prevent removal of the plug portion from the socket portion.   
     
     
         2 . A method according to  claim 1  further comprising:
 applying a prestressing force to urge the lower housing member in the first direction away from the upper housing member. 
 
     
     
         3 . A method according to  claim 2  further comprising:
 applying the prestressing force by turning a plurality of jacking screws evenly spaced around the housing. 
 
     
     
         4 . A method according to  claim 2  further comprising:
 applying the prestressing force by threading a plurality of jacking screws into threaded bores formed on the upper housing member to bear against an upwardly facing mating surface on the lower housing member. 
 
     
     
         5 . A method according to  claim 2  further comprising:
 applying the prestressing force by urging a compressively loaded annular compression sleeve positioned in the chamber against a bearing surface formed on the lower housing member. 
 
     
     
         6 . A method according to  claim 5  further comprising positioning the annular compression sleeve in the chamber between the piston and the upper housing member. 
     
     
         7 .- 9 . (canceled) 
     
     
         10 . 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 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 a compressively loaded compression sleeve positioned in the chamber and urging the lower housing member away from the upper housing member by bearing against a bearing surface formed on the lower housing member.   
     
     
         11 .- 13 . (canceled) 
     
     
         14 . 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;   engaging structure associated with the upper housing member and the lower housing member and configured to permit the engagement and disengagement of the upper housing member with the lower housing member by relative rotation of the upper housing member and the lower housing member, the engaging structure including mutually engaging mating surfaces on the upper housing member and lower housing member;   a prestressing structure configured to urge the lower housing member in the first direction away from the upper housing member, the prestressing structure including a compressively loaded compression sleeve positioned in the chamber and urging the lower housing member away from the upper housing member by bearing against a bearing surface formed on the lower housing member.   
     
     
         15 . A method according to  claim 1  further comprising:
 removably attaching a tool retention member to the lower housing member, wherein when the tool retention member is attached to the lower housing member the tool retention member blocks removal of the work tool from the chamber and detachment of the work tool from the lower housing member, and when the tool retention member is removed from the lower housing member, the work tool may be removed from the chamber and detached from the lower housing member for replacement. 
 
     
     
         16 . A hammer according to  claim 10 , further comprising:
 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.   
     
     
         17 . A hammer according to  claim 14 , further comprising:
 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.   
     
     
         18 . 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;   an engaging structure associated with the upper housing member and the lower housing member and configured to permit the engagement and disengagement of the upper housing member with the lower housing member by relative rotation of the upper housing member and the lower housing member, the engaging structure including mutually engaging mating surfaces on the upper housing member and lower housing member; and   a prestressing structure configured to urge the lower housing member in the first direction away from the upper housing member, the prestressing structure including at least one compression member positioned between the upper housing member and the lower housing member.   
     
     
         19 . The hammer according to  claim 18 , wherein the compression member comprises a compressively loaded compression sleeve positioned in the chamber and urging the lower housing member away from the upper housing member by bearing against a bearing surface formed on the lower housing member. 
     
     
         20 . 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;   an engaging structure associated with the upper housing member and the lower housing member and configured to permit the engagement and disengagement of the upper housing member with the lower housing member by relative rotation of the upper housing member and the lower housing member, the engaging structure including mutually engaging mating surfaces on the upper housing member and lower housing member; and   a prestressing structure configured to urge the lower housing member in the first direction away from the upper housing member, the prestressing structure including at least one tension screw.   
     
     
         21 . A hammer according to  claim 20 , wherein the prestressing structure further includes a compression sleeve urged by tension applied by the at least one tension screw into compressive contact with a bearing surface on the lower housing member. 
     
     
         22 . A hammer according to  claim 21 , wherein the compression sleeve includes at least one sleeve member having a resilient deflector flange.