Abstract: An impact driver in which a drill mode can be selected without fail is provided. In a hammer case, a connecting sleeve is provided so as to be slidable back and forth. At the backward position, the connecting sleeve engages with only a first engaging tooth provided on the outer circumference of the hammer for rotating integrally. At the forward position, it engages with both the first engaging tooth of the hammer and a second engaging tooth of an anvil for rotating integrally with both of them, and thus a drill mode is obtained. Further, an operating bolt is provided in the hammer case to be inserted into a concave groove of the connecting sleeve through a guide groove formed in the hammer case. The operating bolt slides the connecting sleeve to the forward or backward position by its movement in the guide groove.

Abstract: An electric power tool is provided which prevents malfunction with excellent operability even when one operation mode among various modes is selectable. In a gear case of a housing, there are provided a clutch switching groove which engages with a connecting projection of a clutch switching lever, a slit which guides a guide body having a stepped pin which penetrates an impact switching groove to engage with an auxiliary ring, and a percussion switching groove which engages with a connecting projection of a percussion switching lever. In addition, a switching case is externally provided, so that combination of sliding positions of each switching member can be changed. As the switching case can be operated by a switching button, any of all operation modes, which are, a drill mode, an impact mode, a percussion drill mode, and a clutch mode can be selected with the switching button only.

Abstract: An impact driver in which a drill mode can be selected without fail is provided. In a hammer case, a connecting sleeve is provided so as to be slidable back and forth. At the backward position, the connecting sleeve engages with only a first engaging tooth provided on the outer circumference of the hammer for rotating integrally. At the forward position, it engages with both the first engaging tooth of the hammer and a second engaging tooth of an anvil for rotating integrally with both of them, and thus a drill mode is obtained. Further, an operating bolt is provided in the hammer case to be inserted into a concave groove of the connecting sleeve through a guide groove formed in the hammer case. The operating bolt slides the connecting sleeve to the forward or backward position by its movement in the guide groove.

Abstract: An impact driver capable of boring and having an excellent usability is provided. An anvil(8) is arranged so as to slightly move in the axial direction. A first cam(29) having cam gears(30, 30 . . . ) is externally provided at the anvil so as to be integral with the anvil(8). At the rear of the first cam(29), a second cam(31) having cam gears(32, 32 . . . ) and further having cam gears(36, 36 . . . ) at its outer circumference is externally provided to the anvil(8) so as to be rotatable. At the backward position of the anvil(8), the cam gears(30, 32) contacts with each other. On the other hand, in the cylindrical portion(27) of the hammer case(5), an engaging pin(37) capable of engaging with an engaging gear(36) of the second cam(31) is provided. The engaging pin(37) can change its location by the rotative operation of a mode-change ring(40), whereby a percussion mode and a non-percussion mode is selected.

Abstract: A clutch mechanism (17) includes an internal gear (10) and a plurality of cylindrical pins (26) pressed rearward against a front end surface of the internal gear (10) by a coil spring (25) via a flat washer (24). Provided on the internal gear's front end surface are a plurality of cam protrusions (28) corresponding in number and position with the pins (26). Each cylindrical pin (26) has at its rear end surface a circumferentially chamfered edge (27) and each cam protrusion (28) has a pair of guide slope surfaces (29) with same inclination as the chamfered edge (27) of the pin (26).

Abstract: A clutch mechanism (17) includes an internal gear (10) and a plurality of cylindrical pins (26) pressed rearward against a front end surface of the internal gear (10) by a coil spring (25) via a flat washer (24). Provided on the internal gear's front end surface are a plurality of cam protrusions (28) corresponding in number and position with the pins (26). Each cylindrical pin (26) has at its rear end surface a circumferentially chamfered edge (27) and each cam protrusion (28) has a pair of guide slope surfaces (29) with same inclination as the chamfered edge (27) of the pin (26).

Abstract: An electric power tool is provided including a main housing (2) assembled by fitting together right and left casing halves (3, 4), a drive unit (5), a spindle (14) coupled to the drive unit, and a change ring (20). The drive unit includes a DC motor (6), a gear assembly (7), and first and second gear cases (9, 15). The aluminum-alloy second gear case (15) is provided with a connecting portion (17) which has an outer shape that smoothly and continuously connects with the front end of the main housing and which is secured to the main housing by four screws (24) in the axial direction toward the rear portion of the tool. In addition, the second gear case includes a small-diameter journal bearing (16) which extends forwardly from the front end of the connecting portion (17) within the change ring so as to support the spindle of the tool.

Abstract: 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).