McGinn & Gibb, P.C.
Percussion driver drill, and a changeover mechanism for changing over a plurality of operating modes of an apparatus
 A pair of stoppers (47) capable of moving back and forth in an axial direction of a spindle (5) are provided on an outer periphery of a tubular portion (9a) for supporting the spindle (5). As a pair of projections (49) provided on a first change ring (32) are moved in conjunction with the rotation of the first change ring (32) which is capable of changing over the operating mode of a percussion driver drill, the stoppers (47) move back and forth in the axial direction. During a percussion mode and a drill mode, the stoppers (47) abut against a flat washer (50) for fixing an internal gear (13) to restrict the forward movement of the flat washer (50), while, during a clutch mode provided in the first change ring (32) as a third changeover position, the stoppers (47) move away from the flat washer (50). A pair of washers (40, 41) superposed on each other in the axial direction of the spindle (5) are interposed between the first change ring (32) and a second change ring (39). The washer (40) has a click (45) capable of engaging in one of recesses (59) formed in the first change ring (32). The washer (41) has a click (46) capable of engaging in one of recesses (58) formed in the second change ring (39). 
Makita Corporation
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additional inventional inventional inventional
Hidenori Michio Takefumi Takao
Ito Okumura Furuta Kuroyanagi