Abstract: A bolt tightening tool for tightening a nut onto a bolt which comprises an outer sleeve having a nut receiving bore and an engaging groove; an inner sleeve axially movably mounted within the outer sleeve and having a tip receiving bore; and a stopper tiltably disposed in the inner sleeve. The stopper has one end projectable into the tip receiving bore of the inner sleeve and the other end projectable into the engaging groove of the outer sleeve. When a tip is fitted into the tip receiving bore, the tip pushes the stopper to tiltingly move the latter away from the engaging groove, permitting the inner sleeve to retract axially and rendering a nut fittable in the nut receiving bore of the outer sleeve.

Abstract: A power driven rotary tool includes a housing and an electric motor mounted within the housing. A transmission shaft is rotatably supported by the housing, and a drive gear is idly supported by the transmission shaft and is operatively connected to the electric motor. A clutch is provided being engageable with the drive gear, and is rotatably and axially movably supported by the transmission shaft. A slider is axially movably fitted on the transmission shaft, and a spring is operatively connected to the slider for urging the clutch toward the drive gear. A manually-rotatable selector ring is provided and is attached to the housing. The slector ring includes a cam face curved along the peripheral edge thereof and having a plurality of steps formed in a direction axially of the transmission shaft so as to displace the slider by stages in the axial direction for adjusting the amount of compression of the spring.

Abstract: A power driven screwdriver includes a housing, a drive motor mounted within the housing, and a main gear rotatably driven by the drive motor. A spindle is axially movably supported within the housing and has a driver bit secured thereto. The spindle has a groove formed in the rear end thereof. A claw clutch mechanism is provided and is actuated by axial movement of the spindle so as to transmit and disconnect the rotation of the main gear to the spindle. The claw clutch mechanism includes a fixed clutch member formed on the main gear and a movable clutch member mounted on the spindle adjacent the rear end thereof. The movable clutch member has a groove formed in the forward end thereof in opposed relation to the groove of the spindle. One of the grooves of the spindle and the movable clutch member is configured to form an axially inclined groove. Engaging means is interposed between the groove of the spindle and the groove of the movable clutch member.

Abstract: A power miter saw includes a support base and a mounting arm connected to the support base for swinging movement around a vertical axis. A miter saw unit is pivotally connected to the mounting arm. The miter saw unit includes a circular saw blade and a drive motor for driving the saw blade. A blade case is attached to the miter saw unit and is adapted to partially encase the saw blade so as to provide an exposed operational portion of the saw blade. A movable safety cover is mounted on the blade case so as to cover the exposed operational portion of the saw blade. Actuating means is disposed between the mounting arm and the safety cover for directly associating the safety cover with the pivotal movement of the miter saw unit.

Abstract: A depth adjusting device for a screwdriver which is adapted to control within predetermined desired limits the depth to which a fastener may be driven into a work. The depth adjusting device comprises a locking ring retentively engaging the tool housing, and an adjusting sleeve axially movably carried by the locking ring. The locking ring has a spiral ridge formed on the inner periphery thereof, and the adjusting sleeve has a spiral groove formed peripherally about the rear portion thereof and engageable with the spiral ridge of the locking ring. The locking ring also has an axial slit formed therein and a pair of lugs formed across the slit. A thumb screw is provided to tighten the lugs and thence to retain the locking ring on the adjusting sleeve.

Abstract: A portable miter saw for cross-cutting and mitering elongated workpiece has a mechanism interlocked with the turntable for shutting the saw blade clearance gap in the guide fence. The mechanism is provided with a pair of shutter plates slidable on the guide fence and an interlocking piece connected to the shutter plates and movable in operative association with the turntable so as to linearly displace the shutter plates upon rotation of the turntable to selectively change the cutting angle of the saw blade.

Abstract: A portable cordless finishing sander is provided which has a housing, a sanding plate below the housing and a clamping arrangement for clamping a sheet of sandpaper to the sanding plate. The housing has a motor housing portion for storing an electric motor, an elongated handle portion extending above the motor housing portion for storing a battery, and a skirt portion extending below the motor housing portion. The housing is designed in relation to the handle portion and the skirt portion such that the weight of the handle portion encasing the battery is substantially equal to the weight of the skirt portion carrying the sanding plate in both vertical and longitudinal directions. The clamping arrangement includes a clamping member and an operating lever, which are normally stored within the skirt portion of the housing. A novel arrangement is provided for retaining the clamping member in its released position when the sandpaper is exchanged.

Abstract: A safety device for a chain saw conventional in its overall construction is disclosed which comprises mainly a brake lever pivotally supported by the housing of the chain saw and arranged to stop the cutting chain when the brake lever is actuated either by inertia or by engagement with the operator's hand. The brake lever is formed with a cam surface adapted to press an engaging member connected to the drive shaft out of meshing engagement with an interlocking wheel for driving the cutting chain so as to shut off the driving power to be transmitted to the interlocking wheel. The brake lever also includes a braking member secured thereto and adapted for movement therewith in synchronism with the arcuate movement of the cam surface, into frictional braking engagement with the interlocking wheel for effecting a brake effect on the cutting chain.

Abstract: Disclosed herein is an improved nail driving tool comprising a housing including a reciprocable driver, a driver guide fixedly connected to and extending vertically from the lower end of the housing for slidably receiving the driver therein, a handle secured to and extending laterally outwardly from the central portion of the housing, and a magazine including a storing portion adapted to receive a nail package including a multiplicity of nails interconnected in series and a nail guiding portion adapted to guide the leading portion of the nail package to the driver guide, the magazine including a fixed wall portion secured at one end to the driver guide and extending generally below and parallel with the longitudinal extent of the handle and a closure wall portion pivotally movable about the driver guide with respect to the fixed wall portion between an operative closed position and an open position exposing the interior of the magazine.

Abstract: Disclosed herein is a percussive tool having a piston and a ram slidably mounted within a cylinder which is axially displaceable. An air chamber is defined in front of the ram, and the cylinder has exhaust openings formed therein. With the cylinder in its retracted position, the exhaust openings communicate with the front air chamber so that the air cushion therein is vented during forward movement of the ram, and with the cylinder in its advanced position, the exhaust openings are closed to seal the air chamber so that the ram is limited in its rearward movements.

Abstract: Disclosed herein is a vibrator for use in a power drill having a housing and a spindle rotatably and axially movably supported by the housing. The vibrator comprises a rotary cam fitted on the spindle for rotation with the spindle, the rotary cam having a cam surface formed with at least one axially protruding ridge or serration; a clutch cam axially slidably fitted on the spindle and disposed behind the rotary cam, the clutch cam being restricted from rotating about the spindle and releasably engageable with the rotary cam, the clutch cam having a cam surface formed with at least one axially protruding ridge; and a spring adapted to urge the clutch cam toward the rotary cam so as to absorb the axial thrusting force applied to the spindle when the spindle is retracted.

Abstract: A portable electric router conventional in its overall structure is disclosed which includes a locking system comprising a locking pin located in the motor housing and adapted to move in a direction perpendicular to and into locking engagement with the guide bar, and a locking lever pivotally disposed adjacent a grip of the motor housing and operative to axially move the locking pin. The locking lever is adapted to pivot toward the grip to thereby press the locking pin against the guide bar.

Abstract: Disclosed herein is a lawn mower including a motor housing for vertically enclosing a motor; and a cutter casing disposed below the motor housing for housing a cutter fitted to the lower extremity of the shaft of the motor. The cutter casing is connected to the motor housing in such a manner that they communicate with each other. The cutter casing has at the upper portion thereof air-passing ports vertically extending therethrough. There is provided on the cutter casing a shroud for enclosing the motor housing, and the shroud has at a portion thereof apertures opening to communicate with the atmosphere; and air inlets opening to communicate through an air filter with the interior of the motor housing. In the cutter casing and above the cutter, there are provided an air impeller for creating a flow of air to support the mower on a cushion of air; and an axial impeller for cooling the motor. Both impellers are fitted to the motor shaft such that the axial impeller overlies the air impeller.

Abstract: Disclosed herein is a bolt tightening tool for tightening a nut onto a bolt, of the type driven by an electric motor, including an outer sleeve adapted to receive a nut for rotational drive therewith, the outer sleeve having an engaging section provided on the inner periphery thereof; an inner sleeve adapted to receive a bolt-tip formed at the extreme end of a bolt, the inner sleeve being mounted within the outer sleeve and effective to move in one axial direction, the inner sleeve having a window portion provided in and extending vertically through the upper wall portion thereof; an engaging member operatively inserted in the window portion and adapted to move in the radial direction of the inner sleeve for engagement with the engaging section of the outer sleeve; a cylindrical movable member operatively inserted in the inner sleeve for movement in the axial direction of the inner sleeve; and a spherical projection provided on a portion of the outer periphery of the cylindrical movable member and adapted to

Abstract: In an electrically-powered tool, the driving motor of the tool and a switching element for a phase control circuit for controlling the number of revolutions of the motor are connected in series. The switching element is fixed to a field core of the motor. In the phase control circuit for the switching element, a bias resistance between the base and the emitter of a pulse phase controlling transistor for changing the amplification degree by the output from a pulse generating circuit for generating pulses having frequencies corresponding to the numbers of revolutions of said motor is connected in parallel with a capacitor for effectively slowly starting said motor, a first amplifier for changing the output in response to the number of revolutions of said motor and for stabilizing the rotation of said motor, and a second amplifier for producing output upon falling of the number of revolutions of said motor below the preset number of revolution and for limiting overload current.

Abstract: A power cutting tool having a body, a base for supporting the body, and a housing provided at the front end of the body, comprises a substantially saucer-shaped rotary cutter rotatably supported within and by the housing and having a cutting face substantially on the same level as the bottom of the base; a guide roller disposed in front of the housing and adapted to roll on a workpiece surface, which guide roller being vertically movable with respect to said body so as to control the depth of cut of the rotary cutter; a movable cover fitted to the lowermost end of the housing and adapted to annularly enclose the rotary cutter and to cover the workpiece surface so as to define a cutting chamber which in turn is defined into an inside chamber and an outside chamber by the rotary cutter; and a plurality of communicating ports provided on the rotary cutter and adapted to communicate the inside chamber and the outside chamber therethrough.