Robert Boschgmbh

Kurt Paule

Fritz Schadlich

Friedrich Hornung

Karl Wanner

Wilbert Reibetanz

Karl Roll

Eberhard Vogel

Martin Gerschner

Max Burklin

Klaus Gunther

Hermann Adam

A hand tool machine, in particular a drill machine, has a feeler device for determining the diameter of a tool element to be used with the hand tool machine. For measuring the tool elements prior to insertion into the clamping element of the hand tool machine, a feeler device is provided which is arranged separately from the clamping element and is connected with an indicator. The diameter determined by the feeler device is administered to a control unit which is controlling the driving motor. The control unit can also receive in addition further information concerning the material to be treated by means of an input device. In view of the measuring value with regard to the diameter of the tool element and the administered information concerning the material, the optimum rotary speed for the tool element and consequently for the driving motor is determined and adjusted.

Hand tool machine, in particular drilling machine

To permit operation of the power tool only if both hands of an operator are engaged, the tool is formed with a handle portion which has a sensing surface thereon, electrically coupled to a current flow sensing circuit, preferably including an opto-coupler or a field-effect transistor (FET) circuit which permits firing of a triac, thyristor, or the like only if current flows over the sensing surface by area contact therewith. The sensing surface is energized, preferably, from a resistive or capacitative voltage divider; the capacitative voltage divider has the advantage that the triac firing circuit can cause the triac to fire during null or zero crossings of ac supplied power. If a locking-type switch is used, two handles or touch-areas are needed; if a spring-loaded switch is provided, it can function as one safety element, and a touch-area sensing surface as the other.

Electronic two-hand safety system for power tools

Electronic control and regulating system

A hedge trimmer has at least one moveable blade and a second blade. The second blade has trapezoidal teeth. The first blade has rectangular teeth which have a broadened end portion, but, contrary to the prior art, the teeth of the first blade are at least twice as long as those of the second blade. As in the prior art hedge trimmers, the broadest part of each tooth is defined by two juncture points, one on each side of the tooth. For additional safety, in accordance with the invention, the maximum distance between adjacent juncture points of adjacent teeth is 14 mm.

Hedge trimmer

A hand-guided power tool comprises a housing and a base plate mounted below the housing. The base plate is adapted to be juxtaposed with an object which has material to be removed therefrom. A tool element such as a reciprocable cutting blade extends through a slot formed in the base plate and is operative for removing material from the object with concomitant production of undesirable particulate material in the circumambient region of the element. A channel member is also mounted below the housing but at a distance from the base plate to thereby form a suction channel which is in communication with the circumambient region of the tool element and which is operative for removing and guiding the particulate material from the tool element.

Power tool with dust collecting arrangement

A pneumatic hand tool comprises a housing having a compressed-gas inlet and provided with a pneumatically powered motor which carries on one side a tool holder such as a chuck and on the other side a governor. A speed-control valve is operated by the governor and can close a first air passage between the inlet and the motor to maintain the motor speed below a predetermined limit. Another passage is provided which bypasses the governor-controlled speed-control valve and a valve is provided in this bypass conduit which is openable in order to allow the hand tool to operate at a speed substantially above the governor-established speed.

Growing community of inventors

Stuttgart, Germany

Kurt Paule