Abstract: A retaining device for a power drill has multiple brake shoes movably received in the housing, a cam securely engaged with the output shaft to selectively abut the brake shoes to move and engage with an inner periphery of a through hole and a driving disk provided to drive the output shaft and to limit the movement of the brake shoes in the housing. When the brake shoes are moved to engage with the inner periphery defining the through hole, a locking effect is provided to the driving disk so as to the output shaft.

Abstract: A retarding mechanism for a grinding machine which is an improvement on a prior patent application, and comprises a body and a grinding member. Wherein, the body is fixedly provided with an annular plane plate encircling an output axle thereof, the grinding member is fixedly provided with a fixing seat on the rear surface thereof, the retarding mechanism is characterized by that: the fixing seat is provided with a plurality of peripheral abrasive members which are arciform raised portions to render the abrasive members more solid and resistive to grinding and contactable with the plane plate in larger area. Therefore, during rotation of the grinding member, the abrasive members can provide a better structure to get larger friction force with the plane plate to endue the grinding member with a desired retarding effect.

Abstract: A kind of knob switch device relates to a clutch control device setting inside the decreasing box, and relates to a switch device setting outside the decreasing box. The clutch control device comprises the switch block, the switch set, the vibration block and the vibration set on the output shaft serially. The switch device comprises a stop ring, a stop board and a gyrator ring. With rotating the knob, we can drive the stop ring and the gyrator ring to rotate at the same time. Then it makes the screw orbit of the stop ring to push the jut of the stop board. When the clutch transits the device and makes the turning ring to rotate for a fixed angle, and it makes the knob, the inner gear and the turning ring to rotate at the same time. Then the switch block fits the switch teeth and makes the teeth of the vibration block to fit the teeth of the vibration set and make the output draft to have action of vibration at rotating time.

Abstract: A sensing terminal and a receptacle are installed in a charge battery and a charger, respectively. During charging, a charging circuit within the charger will detect whether the battery is pulled out from the charger. If the battery is pulled out, the power source will be turned off in a very short time so that no voltage will be sent from the terminal of the charger in order to protect the charger. As the charge battery is pulled out from the charger, no spark is generated and the battery is prevented from being burned out.

Abstract: A switch device for a screw button is disclosed. The switch device includes a slowdown box with a switch base, which consists of two sets of concave gears with appropriate spacing located on the axial plane around the outer brim, each set having a plurality of switch concave gears. The side on which the switch gears located is formed as a inclined surface, which is used to coordinate with a plurality of switch concave gears corresponding to the switch convex gears where the respective axial surface of the switch base in the switch block are set. The switch block thereby controls the switch convex gears to engage or disconnect with the switch concave gears when rotating. The motion of the output axis in radial direction is manipulated to determine whether the vibrating block fixed on the output axis can vibrate when the output axis is pressed and rotates to induce vibration because engaged with the vibrating base.

Abstract: A retarding device of a grinding machine comprises a casing and a grinding element, wherein the casing is securely installed with a circular flat plate around the periphery of the output shaft installed thereon. A fixing seat is installed on the rear side of the grinding element, and a fixing seat is installed with a plurality of friction elements so that the grinding element is combined with the output shaft, and thus the friction element contacts with the flat plate. Therefore, as the grinding element is rotating, the rotary speed of the grinding element is retarded by the friction forces between the friction elements and the flat plate.

Abstract: A switching device of reduction gear set is coupled to and drive by a planetary gear system for driving an output tool. The switching device includes a casing defining an interior space having an inside surface on which an internal gear is formed. The casing also defines two opposite elongate slots. A switching member is received in the casing and movable between a first position and a second position.

Abstract: A rotatable torque adjusting device which is incorporated in a rotation tool for adjusting output torque of the rotation tool is disclosed. The rotation tool has a front end surface on which a support cylinder is provided to rotatably support an output shaft which provides the output torque. Cavities are provided on the front end surface and surround the support cylinder to each receive a spherical member which applies a force to a rotating disk inside the rotation tool to adjust the output torque. The torque adjusting device includes a cam ring rotatably fit over the support cylinder, having a plurality of circumferentially-extending arc-shaped camming projections, each defining a cam. A follower ring non-rotatably fit over the support cylinder, having camming projections, each defining a follower engageable with the respective cam of the cam ring which converts a relative rotation therebetween into an axial movement of the cam ring.

Abstract: A primary shaft locking device of an electromotive tool is disclosed. A plurality of braking blocks are installed with a plurality of axially projected supporting pieces and a plurality of radially projected nose portions. An output shaft is installed within the receiving hole and a cam is installed in one end of the output shaft so that the cam is rotated synchronously with the output shaft. Furthermore, a driving disk attached to a speed changing gear set is installed, the disk surface of which is installed with a plurality of convex blocks having a fan shape. These convex blocks is matched with the fixing seat, and is arranged between the two supporting pieces installed on the braking blocks. Thereby, when the rotary is driven to rotate, at first, the convex block will rotate the supporting pieces in order that the braking block release from braking condition so as to drive the output shaft, the cam and the braking block to rotate at the same time.