DE3045354C2 - Push button switch - Google Patents

Description

30th

The invention relates to a push button switch, which can be depressed against the force of a return spring The end of the plunger has a magnet that closes contacts as a result of its magnetic field.

Such pushbuttons are already known (DE-AS 25 22 870), where a magnet can be actuated by the push button, by its action in Rest position a switching ball made of ferromagnetic «o Material adheres to a solid plate made of ferromagnetic material. By moving the magnet the ball detaches itself from the plate and creates an electrical connection between the fixed contacts of the switch Bridge connection.

This switch design comprises a relatively large number of components and is manufacturing technology therefore very expensive.

Furthermore, the switching ball always touches the same points on each time the switch is pressed the permanent contacts.

From DE-GM 68 00 740 a magnetically actuated push button switch is known in which on A permanent magnet is attached to the push button, which is held in the rest position on a magnetic plate will. When the button is pressed, the magnet is released from the plate and activates a protective tube contact, whereby a snap action is achieved. When the button is released, the magnet is released from the Protective tube contact pulled away again so that it opens again. There will be with everyone Switching on always uses the same contact points and only transmits relatively small currents. In addition, switches of this type are sensitive to mechanical shocks and are expensive to manufacture. * 5 The invention has for its object to be a

Drucktastenschaltcr of the type mentioned so too i "rbcßern that it is flat, simple and fail-safe carries out the magnetically effected contact without delay. This object is achieved according to the invention solved by the means specified in the characterizing part of claim 1

It is thereby advantageously achieved that the contact carriers all together have a larger contact area offer, since they form a large number of electrical contact points with the fixed contact points, wherein the constant movement of the contact carriers ensures a self-cleaning effect at the same time. In addition, the same contact points never meet the next time the key switch is pressed together.

Furthermore, the push button switch described is insensitive to oxidation and contamination (Dust, moisture, etc.) and enables higher switching capacity.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawing

Fi g. 1 shows a cross section of the push button switch in FIG Rest position and

F i g. Figure 2 is a cross-section of the same push button switch in operational staggering.

The push button switch described includes a button plunger 1, the one at its upper end Key top 2 and at its lower end a magnet 3 carries, and against the force of a The return spring 4 can be depressed. The magnet 3 can be a permanent magnet or an electromagnet. The key tappet 1 with the magnet 3 is on in one Guide housing 5 attached to a printed circuit board 6 provided with surface-treated conductor tracks led To ensure a flat design of the key switch, this housing is in a whole Ladder system covering plate included. On the lower side facing away from the magnet 3 Printed circuit board 6, fixed contact points 7 are arranged, which in one below the circuit board 6 in one not Magnetic material machined recess 8 protrude. At the bottom of this recess 8 are in the rest position at a distance from the contact points 7 several, serving as contact carriers 9, free movable balls approx. 1 mm in diameter, 20 to 30 in number, made of a ferromagnetic, surface-treated material, such as soft iron, exist. Instead of the soft iron balls can be used for the Contact carrier 9 also another ferromagnetic material, such as. B. surface-finished steel corundum in Find use in the form of filings. The interior of the switching system is hermetically sealed, whereby possible oxidation of the contact carrier is avoided.

In the rest position of the pushbutton switch, the contact carriers 9 are on the bottom of the recess 8 outside of the magnetic field emerging from the magnet. When the pushbutton 1, 2 is depressed, after the force of the return spring 4 has been overcome, the magnet 3 approaches the circuit board 6, the contact carriers 9 coming into the effective area of its magnetic field. Due to the effect of this magnetic field, the contact carriers 9 are suddenly drawn onto the lower side of the circuit board 6 and an electrical connection is thus established between the fixed contact points 7 or the conductor tracks of the circuit board. After releasing the button 2, the return spring 4 brings the button plunger I with the magnet λ back into the basic position, with the previously attracted contact carrier 9 on the floor

fall down the depression.

When using electromagnets instead of permanent magnets and with the appropriate arrangement, would be the push button switch described as a high-voltage circuit breaker usable.

1 sheet of drawings

Claims (3)

Patent claims: 1. Push button switch whose plunger can be depressed against the force of a return spring its end carries a magnet that makes contacts by means of its magnetic field, thereby characterized in that on the side facing away from the magnet (3) of the circuit board (6), where fixed Contact points (7) are arranged, a recess (8) is provided in a non-magnetic material Ό is, in which several freely movable contact carriers (9) made of ferromagnetic surface-refined material are housed, which by pressing down the plunger (1) by means of the movement the magnetic field generated by the magnet (3) can be brought to the contact side of the circuit board (6), whereby between the fixed contact points (7) an electrical connection in the form of a multiple Parallel connection of the individual contact carriers (9) is made. 2. Push button switch according to claim 1, characterized in that the contact carrier (9) oberflächenbehandeite Soft iron balls are approx. 1 mm in diameter. 3. Push button switch according to claim 1, characterized in that the contact carrier (9) surface-treated Steel corundum waste (filings) are.