DE1295642B - Contactless row button - Google Patents

Description

The invention relates to a contactless row scanner for generation of electronic control pulses, in particular for electronic input devices Data processing, as well as for industrial and machine tool controls.

Such contactless buttons have compared to those in which to Triggering an electrical function mechanical contacts are essential Advantages. These result from the following properties: bounce-free contact, long service life, constant contact resistance, insensitive to external Influences (moisture and vibration), high switching frequency and low actuation force. Such devices are therefore for high switching frequency and high switching reliability, as required for row keyboards, particularly suitable.

In the case of the known, contactless electronic pushbuttons z. B. as a pulse generator an oscillator that vibrates in the non-switching state, whose ' Vibrations are damped inductively or capacitively in order to trigger a switching process. However, such systems have the disadvantage of a great deal of construction and Shielding elements. Also, they need a supply voltage and are very temperature sensitive. For use with keyboards with mechanical locking, in which the installation space is very limited and in which a standardized, relatively small keyboard pitch (international 4.75 mm) must be adhered to, are such Switching elements are therefore unsuitable or only suitable to a very limited extent.

However, to take advantage of a contactless generation of electronic To be able to use control impulses with serial keyboards without the previous ones Having to accept disadvantages is, according to the invention, the row probe for Generation of electronic control pulses designed so that each button has a rocker switch is assigned, which in a magnetic field relative to at least one current-carrying, the field plate connected to the output terminal is movable and that the rocker is designed as an angle piece, which with its inner corner on a cutting edge of the pole piece of a permanent magnet is mounted, the one rocker leg cooperates with the actuating pin of the keyboard and the other leg of the Magnet is brought into the rest position and held there.

It is based on the property of the field plate as a semiconductor component Made use, after which its ohmic resistance increases in the magnetic field. The invention made possible with simple, wear-free means that take up little space the use of this effect in row keyboards is advantageous.

In addition, this results in a design of the individual pushbutton element, in which the moving masses are very small and where none are susceptible to failure Elements are used. A simplification is also achieved in that the Permanent magnet is also used to control the rocker with every switching process to bring to the rest position and hold there if necessary.

In the further development of this proposal, the rocker is according to the invention designed as an angle piece, which with its inner corner on a cutting edge of the pole shoe is mounted, one rocker leg with the actuating plunger the keyboard cooperates and the other leg of the magnet in the rest position is brought and held there. This results in a construction of the individual Probe element in which the moving masses are very small and with none failure-prone elements are used. A simplification is also achieved by that the permanent magnet is used at the same time to turn the rocker with each switching process to bring to the rest position and hold there if necessary.

Since the field battens can be made very small, can Provide several field plates with a rocker without further ado, which then at corresponding arrangement multiple or alternating circuits can be made.

Furthermore, according to the invention, there is an insulating pad on the upper pole piece provided which so out. is placed that the magnetic effect on the other Seesaw legs predominate. This is a safe reset of the rocker and thus also guaranteed the feeler element in the rest position.

One could = - every key element with a special permanent magnet and line up the individual magnets with the same polarity. To however to simplify the assembly and a better effect due to the larger magnet mass to achieve is a common magnet block for all rockers according to the invention intended.

In the drawing, an embodiment of the invention is enlarged. shown: It shows F i g. 1 the switching system in cross section A-A, F i g. 2 the view from the front.

The permanent magnet block 2 is arranged in a removable housing 1, the upper pole piece 3 of which is provided with a cutting edge 4 on which switching rockers 5 are pivotably supported. The upper leg 6 of the angled rocker is supported on the actuating pin 7. The lower rocker leg 10 is brought into the rest position shown and held there by magnetic force when the actuating pin 7 is relieved.

In the area of the magnetic field, preferably near the magnet 2, each rocker switch 5 is assigned a field plate 12, which is on the lower Pole shoe 13 is attached by part 14 and via the connection plate 15 to a Circuit can be connected.

If the actuating pin 7 is pressed, the associated switching Rocker 5 moved to the dot-dash position, whereby the magnetic field in the area of the field plate 12 is deflected, so that the ohmic resistance the field plate changed.

After releasing the pin 7, the rocker switch 5 or its legs 10 brought back to the starting position by the magnet and held there. Included this holding effect can be achieved by means of an appropriately sized insulating intermediate plate 16 can be adapted to the given circumstances.

The insulating support 17 on the upper pole piece 3 serves a similar purpose. With this support, the tensile force of the magnet exerted on the rocker leg 6 can be coordinated with the attraction force on the leg 10 to such an extent that the latter predominates in any case.

As shown in FIG. 2 is the described contactless switching system particularly suitable in a any long row arranged to The prescribed standard division of 4.75 mm can be adhered to without difficulty can be.

Claims (3)

Claims: 1. Contactless row button for generating electronic control pulses, in particular for input devices for electronic data processing, as well as for industrial and machine tool controls, the switching pulse being generated by the change in resistance of a field plate, characterized in that each button has a rocker switch (5) is assigned, which is movable in a magnetic field relative to at least one current-carrying field plate (12) connected to the output terminal, and that the rocker is designed as an angle piece, which is mounted with its inner corner on a cutting edge (4) of the pole piece of a permanent magnet , one rocker arm (6) interacting with the actuating pin (7) of the keyboard and the other arm (10) being brought into the rest position by the magnet (2) and held there. 2. Contactless Row scanner according to the preceding claims, characterized in that on the upper pole piece (3) is provided with an insulating pad (17) which is designed in this way is that the magnetic effect on the other rocker arm predominates. 3. Contactless row switch according to the preceding claims, characterized in that a common magnet block (2) is provided for all rockers.