Abstract: A working depth adjusting device includes an adjusting member; an intermediate member and an operation member. The adjusting member is supported on the front portion of the tool body and movable along the axis of the spindle, so that the position of the adjusting member can be adjusted relative to the tool bit with respect to a working depth direction. The intermediate member is rotatably supported on the adjusting member. The adjusting member moves in the working depth direction as the inmate member rotates. The operation member is operable to rotate relative to the intermediate member between a lock position and an unlock position. The intermediate member has a first engaging member. When the operation member is rotated to the lock position, the first engaging member engages the tool body, and the engagement of the first engaging member is maintained by the operation member, so that the working depth adjusting device can be prevented from being removed from the tool body.

Abstract: It is an object of the invention to provide a technique that can alleviate noise when the clutch comes into engagement. Representative tightening tool according to the invention comprises a motor, a driven shaft driven by the motor, a tool bit driven by the driven shaft and a clutch mechanism. The clutch mechanism includes a driving-side clutch element, a driven-side clutch element and an engagement speedup mechanism. The engagement speedup mechanism causes the driven-side clutch element to move at higher speed than the driven shaft when the driven-side clutch element moves toward the driving-side clutch element together with the driven shaft so as to engage with the driving-side clutch element. According to the invention, because driven-side clutch element can swiftly move toward the driving-side clutch element by the engagement speedup mechanism, noise when the clutch comes into engagement can be alleviated.

Abstract: It is an object of the invention to provide an effective technique for reducing wear of sliding contact areas in an engagement clutch of a rotary tool. According to the invention, a representative rotary tool may comprise a motor, a tool bit, a driving-side clutch element, a driven-side clutch element, a biasing spring, a rotation preventing member and an enclosure. The biasing spring biases the driven-side clutch element toward the power transmission prevented position. The biasing spring is disposed in a compressed state on the outer peripheral side of the driving-side clutch element and the driven-side clutch element and extends between the driving-side clutch element and the driven-side clutch element. At least part of the biasing spring is enclosed by the enclosure.

Abstract: It is an object of the invention to provide an effective technique for reducing wear of sliding contact areas in an engagement clutch of a rotary tool. According to the invention, a representative rotary tool may comprise a motor, a tool bit, a driving-side clutch element, a driven-side clutch element, a biasing spring, a rotation preventing member and an enclosure. The biasing spring biases the driven-side clutch element toward the power transmission prevented position. The biasing spring is disposed in a compressed state on the outer peripheral side of the driving-side clutch element and the driven-side clutch element and extends between the driving-side clutch element and the driven-side clutch element. At least part of the biasing spring is enclosed by the enclosure.

Abstract: It is an object of the invention to provide a technique that can alleviate noise when the clutch comes into engagement. Representative tightening tool according to the invention comprises a motor, a driven shaft driven by the motor, a tool bit driven by the driven shaft and a clutch mechanism. The clutch mechanism includes a driving-side clutch element, a driven-side clutch element and an engagement speedup mechanism. The engagement speedup mechanism causes the driven-side clutch element to move at higher speed than the driven shaft when the driven-side clutch element moves toward the driving-side clutch element together with the driven shaft so as to engage with the driving-side clutch element. According to the invention, because driven-side clutch element can swiftly move toward the driving-side clutch element by the engagement speedup mechanism, noise when the clutch comes into engagement can be alleviated.

Abstract: It is an object of the present invention to provide a technique for appropriately providing not only for normal rotation but for reverse rotation in a tightening tool having a clutch. Representative tightening tool according to the invention comprises a body, a driving motor housed in the body, a driving-side clutch element, an auxiliary clutch element, a driven-side clutch element, a driven shaft and a tool bit. During normal rotation of the driving motor, the driven-side clutch element is caused to move in the axial direction by application of a pressing force of the user to the body to engage with the driving-side clutch element. During reverse rotation of the driving motor, the driving-side clutch element and the auxiliary clutch element are caused to move relatively with respect to each other in the axial direction by rotating torque of the driving-side clutch element and the driving-side clutch element or the auxiliary clutch element engages with the driven-side clutch element.

Abstract: A bus duct supporting structure in which it is possible to minimize the distance between bus ducts next to each other and reduce space for installation of the bus ducts. In the bus duct supporting structure, bus ducts of a plurality of lines installed in parallel almost in the vertical direction of a structure are supported, wherein each bus duct is supported by supporting parts that are fixedly installed on the structure, and supporting parts that support one bus duct and supporting parts that support another bus duct, the bus ducts being next to each other, are disposed at a distance therebetween in the longitudinal direction of a bus duct.

Abstract: The invention provides a bus duct supporting structure in which it is possible to minimize the distance between bus ducts next to each other and reduce space for installation of the bus ducts. In the bus duct supporting structure, bus ducts of a plurality of lines installed in parallel almost in the vertical direction of a structure are supported, wherein each bus duct is supported by supporting parts that are fixedly installed on the structure, and supporting parts that support one bus duct and supporting parts that support another bus duct, the bus ducts being next to each other, are disposed at a distance therebetween in the longitudinal direction of a bus duct.

Abstract: The present invention relates to a powered screw driver having a spindle 20 that is caused to rotate by an electric motor 10 within a range of about 5000 rpm (revolutions per minute) to about 7000 rpm (revolution per minute) when the spindle 20 idles. Because the spindle 20 rotates at a high revolution speed, the screw-fastening operation can more quickly be completed when the user of the screw driver 1 fastens the screw in a normal posture. The screw driver 1 may used to fasten screws having a pitch within a range of about 1.3 mm to 2.0 mm (i.e. about {fraction (1/32)} inch to {fraction (3/32)} inch).

Abstract: A screwdriver 1 includes a hook 7 which is configured to fit in an accommodating recess 20 grooved in a motor housing 4 and a handle cover 5. The hook 7 includes an extending portion 8 for being accommodated in a first groove 21 and a base block 9 for being accommodated in a second groove 22. The base block 9 is provided with a pair of slide plates 10 which in turn includes retainer flanges 11 at its free ends. To draw out the hook 7, it is manually pulled up at the top end of the extending portion 8 and slid rearward so that the retainer flanges 11 of the slide plates 10 enter support slots 27 provided at the rear of the second groove 22. Simultaneously, a support plate 12 of the base block 9 abut the top wall 5a of the handle cover 5. In this drawn-out position, as the retainer flanges 11 interfere with the edges of the support slots 27, the hook 7 is prevented from slipping out the screwdriver 1 and secured on the handle cover 5 outside the accommodating recess 20.

Abstract: A speed change device, preferably for a power tool, may include a first drive gear and a second drive gear mounted on a drive shaft, and may include a first driven gear and a second driven gear mounted on a driven shaft. When the second drive gear is in a first position, a first gear portion of the second drive gear engages the second driven gear, so that the rotational energy of the drive shaft is transmitted to the driven shaft via a first transmission path through the second drive gear and the second driven gear. When the second drive gear is in a second position, a second gear portion of the second drive gear engages the first drive gear, so that the rotational energy of the drive shaft is transmitted to the driven shaft via a second transmission path through the second drive gear, the first drive gear and the first driven gear.

Abstract: To obviate the necessity of a plier or other tool for extracting a driver bit from a screwdriver, and prevent an adjustment sleeve detached from the screwdriver from being lost. The stop ring has an oval dusting opening having a width wider than the distance between the opposite sides of the hexagonal cross section of the driver bit and narrower than the diagonal length of the cross section. After detaching the adjustment sleeve from the screwdriver, the parallel sizes of the oval dusting opening of the stop ring are aligned with the opposite sides of the driver bit, and the stop ring is moved toward the driver bit, until a peripheral groove portion of the driver bit reaches the edge surrounding the dusting opening. By changing the relative angle between the adjustment sleeve and the driver bit, the diagonal part of the driver bit is caught by the edge surrounding the oval dusting opening.

Abstract: Apparatus for indicating incomplete and complete fastening of a screw includes a washer and a ring of a generally flat synthetic resin sheet. The washer includes a pair of washer portions of a generally flat, round shape and a joint portion interconnecting the washer portions to face them in opposite directions to enable the washer portions to receive a shank of a screw in the openings thereof. The lengthwise section of the joint portion forms generally a U shape. The ring is made of a generally round, deformable material and is inserted between the pair of washer portions thus facing each other. The deformable material is expanded radially outward, when compressed by the washer portions receiving the shank of the screw when fastened. Upon the compressive force reaching a predetermined value, the ring will be broken due to the pair of washer portions overlaying one another.

Abstract: A screw member having a plurality of heads by providing one or more thin neck portions to be sheared at a predetermined torque, in which a collar having a skirt portion with its one part being cut away is fitted on the thin neck portion from the lateral side to expose the outer head part alone and to engage the cap member fitted from the side of the bearing surface of the inner head part of the screw member, and the cap member is inserted between the skirt of the collar and the inner head part to thereby prevent the collar from slipping out.

Abstract: A screw member having a plurality of heads by providing one or more thin neck portions between them to be sheared at a predetermined torque, wherein a cap member surrounding the outer periphery of an inner head part from the side of its bearing surface is engaged with the inner head part so as not to displace outwardly slipping out of it, and the inner peripheral surface of the cap member is made conformable to a shape of the outer peripheral surface of a socket of a screw driving tool to be fitted on the inner head part.