Importance

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Abstract

A hand held hammer machine comprises a housing (10) with a cylinder (11) therein, in which a reciprocating drive piston (40) via a gas cushion in a working chamber (44) repeatedly drives a hammer piston (15) to impact on the neck (17) of a tool (20) carried by the machine housing (10) as soon as a feeding force is applied via the machine housing (10) to the tool (20) and an interposed recoil spring (23) pre-stressed between fixed shoulders (28,22) in the housing (10) starts being compressed in response to tool penetration into the housing (10). Therein and within the spring (23) and around the path of movement of a piston rod (13) of the hammer piston (15) is affixed one end (26) of a sleeve (25), which by its other end forms a stop (30) limiting the penetration of the tool neck (17) into the machine housing (10) to a maximally allowable extent. The range of movements of the neck (17) wherein it can receive repetitive impacts lies between beginning and maximal compression of the spring (23) counted from its precompressed state which defines an idle position for the neck (17), and in that idle position and within that range proper uncovering of porting (45) in the cylinder wall is assured with the hammer piston seal (16) out of hazardous alignment with said porting (45) at the impacting instants.

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First Claim