Preh Elektrofeinmechanische Werke Jakob Preh Nachf Gmbh & Co.

Preh, Elektro-feinmechanische Werke, Jakob Pre Nachf

Gerhard Spiller

Karl-Heinz Bauer

Franz Rutterschmidt

Gebhard Then

It should be possible to adjust without difficulty the moment of friction curring during rotation on a variable resistor. A bolt (11) is provided for this purpose for holding a rotating part (13) axially in position with a base component (2). A tap (24) is brought into contact with a resistance track (5) rotating in the base component (2) in a radial direction to the axis of rotation (14). The bolt (11) can at the same time be used for securing the variable resistor (1) and as the electrical connection for the tap (24).

Variable resistor

A locking slide switch is adapted to set a resistor depending on the length f travel. A key body has a row of teeth with which a pinion meshes. A locking push-button is provided on the shaft of the pinion. In order to make locking from both sides possible, a second pinion or an elongated pinion is guided in the row of teeth. On this pinion is provided a second push-button, which can also be blocked. An on-off switch is additionally provided.

Locking slide switch

In a switch, for example, for a device such as a drill, a key switches an ectrical switching bridge at the beginning of the key displacement. A variable resistor is adjusted depending on the travel of the key, thereby controlling device speed. In order to achieve an adjustment of the key end stop, a slide displaceable in the transverse direction is mounted on the key, which slide has a stop edge projecting in the longitudinal direction. A stop border is provided on the switch cover and configured relative to the travel of the slide so that the distance between the stop edge and the stop border varies according to the displaced position of the slide, thereby enabling operator control of the device speed.

Switch with speed control

A housing made of insulating material has a plurality of slots each accommodating a contact spring including a pair of legs. The free ends of each leg are formed as contact noses facing each other. The contact noses define an opening through which an edge of a printed circuit board may be inserted with the board held at an angle with respect to its final position. The printed circuit board is then rotated about an axis parallel to the edge into its final position in which it is locked by a pair of resilient detent tongues formed at the ends of the housing. In this final position, conductor strips provided at the inserted edge of the printed circuit board make electrical contact with the noses of the contact springs. During rotation of the circuit board, minute sliding movements occur at the contact locations providing a cleaning effect on the contacts without causing excessive wear thereof.

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Saal/Saale, Germany

Gerhard Spiller