Abstract: An electric hand plane has a wedge-shaped body having a lower wedge surface adapted to rest on a workpiece and an upper wedge surface, a plane housing supported on the upper wedge surface of the wedge-shaped body and having a counter-surface, a device for producing a clamping force between the upper wedge surface of the wedge-shaped body and the counter-surface of the housing, and a single handle operative for cancelling the clamping force during an adjustment and also for displacement of the wedge-shaped body, and a gear mechanism means arranged so that the handle displaces the wedge-shaped body relative to the plane housing via the gear mechanism means by rotation.

Abstract: A chain saw is provided with an oil pump for supplying oil to the saw chain. The pump includes a piston immersed in a chamber formed in the housing of the saw and rotatable by a gear rigidly connected to the piston and rotated by another gear driven by a motor. The gear connected to the piston has an inclined end face which wobbles upon the rotation of the gear and is pressed by a helical spring against a supporting ball which is positioned in a recess of a flange bolt manually turnable from the outside of the housing. The path of adjustment of the supporting ball is greater than the diameter of the piston. The working pressure generated by the spring is translated directly to the piston.

Abstract: To permit reliable turn-OFF of the motor when the torque of the motor is sufficient to provide for reliable seating of a screw or nut being driven thereby, start conditions of the motor are sensed, either in form of low-current condition or high power factor; high-torque conditions are sensed by low power factor, or high-current, in dependence on the desired torque level which results, respectively, in a comparatively steep phase angle-torque or current level-torque curve. A switch control is energized to turn-OFF the motor current if the phase angles, or the motor current, respectively, are beyond predetermined levels. To prevent in-rush current, or high power factors from affecting the operation of the turn-OFF system, timing circuits are provided to disable the turn-OFF system when the motor is first turned-ON or if the phase angle difference, as determined by time-comparator networks, between current and voltage, is below a predetermined value.

Abstract: A power screwdriver that is equipped with a spring coupling between the motor drive and the tool spindle, a signal that indicates that a certain value of torque has been overstepped, at which the screwdriver must be sopped, first causes reversal of the motor, but before the motor appreciably turns in the reverse direction, powers shut-off, allowing the motor to coast. After another brief interval, power is reapplied to the motor in the original direction, again briefly. In this way it is possible for the final shut-off to occur when the motor is stopped and the spring is unstressed, avoiding oscillations of the motor-spring system. A triac bridge circuit makes possible quick reversals and brief applications of power. In such a bridge circuit, precautions must be taken to be sure one pair of triacs is extinguished before the other pair is ignited.

Abstract: A torque limiting power screwdriver includes a housing in which there is supported for rotation and axial displacement a screwdriver spindle. A transmission transmits power from a motor to the screwdriver spindle. A torque overload coupling and a separating coupling are interposed in the transmission, being operative for interrupting the transmission of torque from the motor to the screwdriver spindle. The separating coupling is coupled and uncoupled in response to axial displacement of the screwdriver spindle between its coupling and uncoupling positions. The axial movement of the spindle is accomplished by a trigger movably mounted on the housing and connected by a Bowden cable or a lever transmission to the spindle. The spindle is connected by an axially movable coupling with an output member, especially with a bevel gear transmission accommodated in an angular head housing portion. A switching trigger is used to energize and de-energize the motor.

Abstract: A power screwdriver has a drive motor and a tool holder arranged in a housing, a driving coupling including a driving coupling part driven by the motor and a driven coupling part, and a locking coupling arranged between the driving coupling and the tool holder, wherein the couplings are arranged so that when the tool holder is pressed against a screw the coupling parts of the driving coupling are connected with one another and torque from the motor is transmitted to the tool holder in a normal manner, when thereafter a limit torque is attained the locking coupling is overrun, the driving coupling part of the driving coupling is arrested, and the driven coupling part of the driving coupling is disconnected from the driving coupling part, and when the tool holder is pressed stronger against the screw which is difficult to screw in the driven coupling part displaces and follows the driving coupling part and is again connected with the latter so as to again provide for transmission of the torque from the motor to

Abstract: In order to improve the holding power of a tool chuck, especially a tool chuck for use with percussion or impact drills, without the use of elastic friction elements that impede intentional opening and closing, the invention describes a tool chuck in which cooperating, preferably conical surfaces disposed respectively, on the stationary collet and the rotating structure of the chuck engage one another when the chuck is closed and clamps the inserted tool. Additional relative rotation imparted to the rotating structure with respect to the collet causes clamping forces to be applied to the inserted tool and further causes the cooperating conical surfaces to be pressed against one another, thereby generating high surface pressures which oppose the unintentional opening of the chuck even during the presence of axial percussion shocks.

Abstract: A driven output shaft is mounted in a housing and has freedom of limited axial displacement between a first and a second position. A biasing spring permanently biases the output shaft to the first position. An impact member surrounds the output shaft and has a plurality of angularly spaced first axial projections which interdigitate with angularly spaced second axial projections provided on a disk member axially fixed on and turnably surrounding the output shaft. A retaining arrangement is provided in the housing and is engageable with the disk member to prevent rotation of the same when an axial force is exerted upon the output shaft counter to the action of the biasing spring, causing axial displacement of the output shaft to the second position thereof, and engagement of the disk member with the retaining arrangement.

Abstract: An axially reciprocable rotary spindle is mounted in the housing, and a first biasing arrangement urges the spindle in one axial direction outwardly of the housing. An impact member is mounted on this spindle for rotation with but limited axial displacement relative to the same and has an outer circumferential surface provided with cams inclined axially and circumferentially of the spindle and formed with one interruption per cam. A second biasing arrangement urges the impact member also in the aforementioned axial direction, and a fixedly mounted guide ring surrounds the impact member and forms a race for roller bodies corresponding in number to the interruptions and which roll in contact with the circumferential surface and the cam.