Black Decker Inc.

Achim Jung

Ian S Bell

René Jäger

Michael Stirm

Robert Bradus

Norbert Hahn

Robert Alan Usselman

Stefan D Gensmann

Ralf Seebauer

Martin Lauterwald

René´ Jäger

Robert Usselmann

Ian Stephen Bell

Robert Alan Usselmann

When the mode change knob of a multi-mode hammer drill is moved to the hammer only position, an electronic sensor sends a signal to a control logic circuit. When the user then depresses the trigger mechanically closing the ON/OFF switch, the control logic circuit applies a voltage either to a holding relay or to the gate of a triac which enables the relay or triac to conduct, thus providing a parallel circuit by-passing the ON/OFF switch. Consequently, when the user releases the trigger and opens the ON/OFF switch, the parallel relay or triac maintains current flow to the motor. It can be seen that in hammer only mode the user can activate the hammer drill by simply tapping the trigger to depress it and does not need to hold down trigger during use of the hammer in operation.

Actuation apparatus for power tool

A hand held motor driven electrically powered tool, in particular a rotary hammer, comprising a spindle () for rotatingly driving a tool or bit (), a spindle rotary drive train () for rotatingly driving the spindle () and an arrangement for detecting blocking events (). Blocking events occur when the tool or bit of the tool become rotationally fixed in the material being bored in which case the rotary drive on the spindle from the motor causes the tool housing to rotate in a user's grip. According to a first aspect of the invention an overload clutch () is provided in the spindle rotary drive train for transmitting rotary drive to the spindle below a predetermined torque and slipping above the predetermined torque arranged such that the overload clutch cuts off rotary drive to the spindle, for example by reducing the predetermined torque at which the overload clutch () slips when a blocking event is detected so as to cut off rotary drive to the spindle in response to a blocking event being detected. According to a second aspect of the invention there is provided a mode change mechanism () for selectively disengaging a clutch () so as to cut off the rotary drive to the spindle () and the clutch is disengaged when a blocking event is detected so as to cut off rotary drive to the spindle in response to a blocking event being detected.

Rotary tool

A hammer drill comprising: a motor; a drive transmission capable of operating in at in at least a rotary mode and a reciprocating mode; a mode change mechanism; a switch which, when closed, provides power to the motor; and a mechanical lock-on mechanism which, when locked mechanically holds the switch closed to maintain the power to the motor. Additionally, the hammer drill includes a first sensor, which indicates the mode of operation of drive transmission; and a second sensor which indicates whether the lock-on mechanism is locked; and a controller which is capable of interfering with the operation of the motor, when the controller detects that the drive transmission is in the rotary mode of operation and the lock-on mechanism has been locked.

Hammer drill with selective lock-on

Growing community of inventors

Armsheim, Germany

Achim Jung