Patent ID: 7516801
Filing Date: 2009-04-14
Classification: B25D

Abstract:
1. A percussion mechanism for a repetitively hammering hand power tool in the form of a rotary hammer, the percussion mechanism having a striker ( 2 ), movable axially forward and backward in a guide barrel ( 1 ) and imparting impacts directly to an end section of a tool bit ( 4 ) that is insertable into the hand power tool, having a device ( 5 ) that exerts pressure on the striker ( 2 ), by which the striker ( 2 ) is capable of being set into a forward motion in the direction of the tool bit ( 4 ), wherein a blocking element ( 10 ) is provided, with which the striker ( 2 ) is blockable in its forward motion; and wherein the striking frequency of the striker ( 2 ) is adjustable by controlling the blocking time of the blocking element ( 10 ), so that the striking frequency of the striker ( 2 ) depends on how long the blocking element ( 10 ) blocks the forward motion of the striker ( 2 ), wherein the device exerting pressure on the striker ( 2 ) comprises a pressure reservoir ( 5 ) that is fillable with a gas and that is located on the side of the striker ( 2 ) diametrically opposite the tool bit ( 4 ), and wherein the blocking time of the blocking element ( 10 ) is controllable as a function of a pressure level in the pressure reservoir ( 5 ).