Licentia Patent-verwaltungs Gmbh

Rudolf Hoyer

Erwin Stiltz

Heinz Lindenmayer

The housing for electric tools comprises a one-piece plastic construction and includes a handle part and a hollow housing part having a metal jacket therein which defines various cavities and bearing bushes and bores for the elements of a drive motor and an eccentric drive for a hammer drill.

Housing for electric tools

A hammer drill comprises a housing with a cylinder in the housing defining a cylindrical piston chamber and an air chamber located around at least a portion of the piston chamber sealed against the ambient atmosphere and against adjacent components of the housing. The housing defines a tool-receiving chamber aligned with and communicating with the piston chamber and a percussion body is movable in a piston chamber against a tool positioned in the tool-receiving chamber. The piston is reciprocated through a crank drive by an electric motor within the housing toward and away from a percussion body. The cylinder defines a pneumatic buffer zone between the piston and the percussion body so that air which is displaced by the movement of the piston provides a coupling and buffing fluid between the piston and the percussion body. The cylinder is provided with a first air passage opening which communicates with the air chamber and the buffer zone, and it is spaced from the piston when the piston is in a forward dead-center position. The housing has a collar-receiving recess and a radially extending annular collar-shaped shoulder is defined on the cylinder and it extends into the recess. The collar is provided with air passages therethrough, and it determines the spatial position of the cylinder in the housing. The housing and the cylinder are in form-locked interengagement.

Hammer drill with drive and percussion elements accommodated in a

A hammer drill has a housing, a tool shaft rotatably and axially displaceably supported in the housing, a motor, a gearing connecting the motor with the tool shaft and a striking mechanism for imparting successive impacts to the tool shaft. The striking mechanism includes an axially movable striking element. The hammer drill further has a clutch component mounted on the tool shaft and having an engaged state in which it is operatively connected to the striking element and a disengaged state in which it is disconnected from the striking element, and a drive element connecting the motor with the clutch component to rotate the latter. The drive element and the clutch component are arranged axially slidably relative to one another. The striking mechanism further has an intermediate member supported next to and in axial alignment with the clutch component. The intermediate member has coupling elements operatively connected to the clutch component in the engaged state of the clutch component in which the striking mechanism is in an operating state. The coupling elements are disconnected from the clutch component in the disengaged state of the clutch component in which the striking mechanism is in a non-operating state. The intermediate member at least partially surrounds the striking element for guiding the same in its axial motion. The tool shaft has an inner terminus which is positioned externally of the outline of the striking mechanism.

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Althutte, Germany

Rudolf Hoyer