Patent ID: 7174969

Claim:
An electrically powered rotary hammer comprising a housing ( 10 ); a tool holder ( 36 ) located at a forward end of the housing within which a tool or bit ( 34 ) can be releasable mounted so as to be rotatingly driven and so as to be able to undergo limited reciprocation; a rotary drive mechanism ( 2 , 6 , 40 , 4 , 36 ) mounted within the housing for rotatingly driving the tool or bit; a hammering mechanism ( 2 , 6 , 12 , 18 , 20 , 26 , 24 , 4 , 3 , 5 ) mounted within the housing for repeatedly impacting the tool or bit; a first switchable gear arrangement ( 72 ) selectively moveable into an actuating position for actuating the hammering mechanism; and a second switchable gear arrangement ( 40 ) selectively moveable into an actuating position for actuating the rotary drive mechanism; wherein the hammer additionally comprises a mode change arrangement comprising: a mode change knob ( 21 ) moveably mounted on the housing; a linkage support ( 42 ) mounted on the housing; a first linkage ( 30 ) slideably supported in the linkage support for communication between the mode change knob ( 21 ) and the first switchable gear arrangement ( 72 ); and a second linkage ( 32 ) slideably supported in the linkage support for communication between the mode change knob ( 21 ) and the second switchable gear arrangement ( 40 ); the mode change arrangement arranged such that movement of the knob ( 21 ) moves the linkages ( 30 , 32 ) between three positions, a drilling only mode position in which the second switchable gear arrangement ( 40 ) only is in its actuating position, a hammer drilling mode position in which both the first and second gear arrangements ( 72 , 40 ) are in their actuating position and a hammering only mode position in which the first switchable gear arrangement ( 72 ) only is in its actuating position.