Pneumatic hammer

Claim 2

A pneumatic hammer comprising: a housing having an inner surface; a barrel mounted in said housing and axially movable relative thereto; said barrel having a forward end and an outer surface; an air-distribution device and an impact mechanism accommodated in said barrel to ensure reciprocations of a hammer piston under the action of compressed air, with the hammer piston imparting blows to a shank of a working tool received in the forward end of said barrel; the outer surface of said barrel and the inner surface of said housing defining an annular space therebetween; a handle having trigger means for controlling the supply of compressed air into said barrel, the handle being rigidly secured to said housing; a first portion of said barrel having a smaller diameter adjacent to said handle; a second portion of said barrel having a greater diameter; a shoulder formed between said first and second portions of the barrel, an end wall of said shoulder facing said handle; sealing members comprising bushings mounted on said first and second portions of said barrel; said bushings having outer peripheries and end faces, the end faces being in sealing engagement with the housing, annular spaces provided between the outer periphery of said bushings and the inner surface of said housing; a spring member mounted between said bushings; and guide members between said housing and said barrel, whereby said sealing members are relieved from the radial load, so that their wear is reduced, as well as compressed air leakage.

Claim 3

The pneumatic hammer according to claim 1, wherein said guide members comprise at least one annular row of guide projections provided on the outer surface of said barrel, with said row including at least three projections.

Claim 4

The pneumatic hammer accoording to claim 2, wherein the dimensions of said projections in the axial and circumferential directions are substantially smaller than the diameter of the contact surface between the projection and said housing.

Claim 5

The pneumatic hammer according to claim 1, wherein said guide members comprise at least one annular row of guide projections provided on the inner surface of said housing, with said row including at least three projections.

Claim 6

The pneumatic hammer according to claim 4, wherein the dimensions of said projections in the axial and circumferential directions are substantially smaller than the diameter of the contact surface between the projection and said barrel.

Claim 7

A pneumatic hammer comprising: a housing having an inner surface; a barrel mounted in said housing and axially movable relative thereto; said barrel having a forward end and an outer surface; an air-distribution device and an impact mechanism accommodated in said barrel to ensure reciprocations of a hammer piston under the action of compressed air, the hammer piston imparting blows to a shank of a working tool received in the forward end of said barrel; the outer surface of said barrel and the inner surface of said housing forming an annular space therebetween; a handle having a trigger means for controlling the supply of compressed air into said barrel, said handle being rigidly secured to said housing; a first portion of said barrel having a smaller diameter adjacent to said handle; a second portion of said barrel having a greater diameter; a shoulder formed between said first and second portions of the barrel, an end wall of said shoulder facing said handle; sealing members comprising bushings mounted on said first and second portions of said barrel; said bushings having outer peripheries and end faces, the end faces being in sealing engagement with the housing, annular spaces formed between the outer periphery of said bushings and the inner surface of said housing; a spring member mounted between said bushings; at least one annular row of guide projections provided on the outer surface of said barrel, with said row iNcluding at least three projections, whereby the sealing members are relieved from the radial load so that their wear is reduced, as well as compressed air leakage.

Claim 8

A pneumatic hammer comprising: a housing having an inner surface; a barrel mounted in said housing and axially movable relative thereto; said barrel having a forward end and an outer surface; an air-distribution device and an impact mechanism accommodated in said barrel to ensure reciprocations of a hammer piston under the action of compressed air, the hammer piston imparting blows to a shank of a working tool received in the forward end of said barrel; the outer surface of said barrel and the inner surface of said housing forming an annular space therebetween; a handle having a trigger means for controlling the supply of compressed air into said barrel, said handle being rigidly secured to said housing; a first portion of said barrel having a smaller diameter adjacent to said handle; a second portion of said barrel having a greater diameter; a shoulder formed between said first and second portions of the barrel, an end wall of said shoulder facing said handle; sealing members comprising bushings mounted on said first and second portions of said barrel; said bushings having outer peripheries and end faces, the end faces being in sealing engagement with the housing, annular spaces formed between the outer periphery of said bushings and the inner surface of said housing; a spring member mounted between said bushings; at least one annular row of guide projections provided on the outer surface of said barrel, with said row iNcluding at least three projections, whereby the sealing members are relieved from the radial load so that their wear is reduced, as well as compressed air leakage.

Claim 9

The pneumatic hammer according to claim 6, wherein the dimensions of said projections in the axial and circumferential directions are substantially smaller than the diameter of the contact surface between the projection and said housing.

Claim 10

A pneumatic hammer comprising: a housing having an inner surface; a barrel mounted in said housing and axially movable relative thereto; said barrel having a forward end and an outer surface; an air-distribution means and an impact mechanism accommodated in said barrel to ensure reciprocations of a hammer piston under the action of compressed air, the hammer piston imparting blows to a shank of a working tool received in the forward end of said barrel; the outer surface of said barrel and the inner surface of said housing forming an annular space therebetween; a handle having trigger means for controlling the supply of compressed air into said barrel, said handle being rigidly secured to said housing; a first portion of said barrel having a smaller diameter adjacent to said handle; a second portion of said barrel having a greater diameter; a shoulder formed between said first and second portions of said barrel, an end wall of said shoulder facing said handle; sealing members comprising bushings mounted on said first and second portions of said barrel; said bushings having outer peripheries and end faces, the end faces being in sealing engagement with said housing, annular spaces provided between the outer periphery of said bushings and the inner surface of said housing; a spring member mounted between said bushings; and at least one annular row of guide projections provided on the inner surface of said housing, with said row including at least three projections, whereby the sealing members are relieved from the radial load so that their wear is reduced, as well as compressed air leakage.

Claim 11

A pneumatic hammer comprising: a housing having an inner surface; a barrel mounted in said housing and axially movable relative thereto; said barrel having a forward end and an outer surface; an air-distribution means and an impact mechanism accommodated in said barrel to ensure reciprocations of a hammer piston under the action of compressed air, the hammer piston imparting blows to a shank of a working tool received in the forward end of said barrel; the outer surface of said barrel and the inner surface of said housing forming an annular space therebetween; a handle having trigger means for controlling the supply of compressed air into said barrel, said handle being rigidly secured to said housing; a first portion of said barrel having a smaller diameter adjacent to said handle; a second portion of said barrel having a greater diameter; a shoulder formed between said first and second portions of said barrel, an end wall of said shoulder facing said handle; sealing members comprising bushings mounted on said first and second portions of said barrel; said bushings having outer peripheries and end faces, the end faces being in sealing engagement with said housing, annular spaces provided between the outer periphery of said bushings and the inner surface of said housing; a spring member mounted between said bushings; and at least one annular row of guide projections provided on the inner surface of said housing, with said row including at least three projections, whereby the sealing members are relieved from the radial load so that their wear is reduced, as well as compressed air leakage.

Claim 12

The pneumatic hammer according to claim 8, wherein the dimensions of said projections in the axial and circumferential directions are substantially smaller than the diameter of the contact surface between the projection and said barrel.