Holding device for the inner seal of a fluid-operated percussion drive

Abstract

An apparatus having a housing ( 5 ) that shields a front of a percussion drive ( 1 ) against the environment, and into which a drive driven tool ( 3 ) projects. An exchangeable outer seal ( 10 ) is disposed at the housing opening ( 6 c ) for the tool ( 3 ), surrounds the tool transversely to its longitudinal axis ( 3 a ) with spacing, and is moveable in this transverse direction. An inner seal ( 11 ) is disposed behind the outer seal ( 10 ), and rests elastically against the tool ( 3 ) outside of its tool guide ( 2 ). The inner seal ( 11 ) is exchangeably secured to an elastic extension ( 12 ) of the tool guide ( 2 ) that surrounds the percussive tool ( 3 ) in the region of the inner seal ( 11 ) with a spacing larger than the largest transverse displacement of the tool ( 3 ). The extension ( 12 ) is an independent, elastic support that forms a detachable connection with the tool guide ( 2 ) at one end.

What is claimed is:  
     
         1 . An apparatus comprising: 
 a fluid-operated percussion drive;    a housing part that shields the percussion drive, at least at the front, against the environment, and into which a percussive tool driven by the drive projects axially into a tool guide of the drive;    an exchangeable outer seal disposed at an opening provided in the housing part for the tool, with the seal surrounding the tool, transversely to its longitudinal axis, with at least some spacing, and being seated for movement in the transverse direction;    an inner seal disposed behind the outer seal, when seen counter to the direction of action of the tool, and resting in an elastic manner against the tool, outside of said guide, with the inner seal being secured, so as to be exchangeable, to an axial extension of the tool guide in the direction of the action of the tool, said extension surrounding the percussive tool in the region of the inner seal, with a spacing that is larger than the largest possible transverse displacement of the percussive tool in the housing; and wherein: 
 said extension is an independent, elastic support element that, on its rear side facing away from the inner seal, has a beginning segment that forms a detachable connection with a receiving segment of the tool guide in the longitudinal and transverse directions; and  
 the extension latches in the receiving segment of the tool guide that is designed to secure the extension in a snap connection.  
   
     
     
         2 . The apparatus according to  claim 1 , wherein the extension is formed of a thermoplastic elastomer.  
     
     
         3 . The apparatus according to  claim 2 , wherein the thermoplastic elastomer is polyurethane.  
     
     
         4 . The apparatus according to  claim 1 , wherein the connection is produced at least partially inside the tool guide.  
     
     
         5 . The apparatus according to  claim 1 , wherein the extension is supported on the outside of the tool guide facing away from the percussive tool.  
     
     
         6 . The apparatus according to  claim 1 , wherein the tool guide has at least one annular-groove-type depression as a component of the connection.  
     
     
         7 . The apparatus according to  claim 6 , wherein the at least one annular-groove-type depression is formed on the outside of the tool guide facing away from the percussive tool.  
     
     
         8 . The apparatus according to  claim 6 , wherein the annular-groove-type depression is additionally undercut, at least on one of the side facing the inner seal and the side facing away from the inner seal.  
     
     
         9 . The apparatus according to  claim 7 , wherein the annular-groove-type depression is additionally undercut, at least on one of the side facing the inner seal and the side facing away from the inner seal.  
     
     
         10 . The apparatus according to claims  6 , wherein the annular-groove-type depression is formed as a front-side depression that originates on the front side of the tool guide that faces the inner seal.  
     
     
         11 . The apparatus according to  claim 10 , wherein the front-side depression is undercut in the direction of the tool guide.  
     
     
         12 . The apparatus according to  claim 1 , wherein the extension is additionally held in position in the direction of the receiving segment of the tool guide by at least one annular securing element.  
     
     
         13 . The apparatus according to  claim 1 , wherein the extension has at least one annular latch that extends into the receiving segment of the tool guide.  
     
     
         14 . The apparatus according to  claim 13 , wherein at least one latch of the extension is supported in a non-positive lockup on the receiving segment.  
     
     
         15 . The apparatus according to  claim 1 , wherein the wall thickness of the extension, with the exception of the beginning segment that produces the connection, and its end segment, that supports the inner seal, decreases in the direction of the end segment.  
     
     
         16 . The apparatus according to  claim 1 , wherein an inner diameter of the end segment of the extension that supports the inner seal is larger than an inner diameter of its beginning segment that produces the connection.