IL100197A - Inertial signal-generating device - Google Patents

Description

REF .: 2020/91 INERTIAL SIGNAL-GENERATING DEVICE 2020/91 -1- INERTIAL SIGNAL-GENERATING DEVICE The present invention relates to an inertial signal-generating device of improved design.

Inertial signal-generating devices are known in the art, and generally comprise an element which is free to bend under inertial forces, and the bending of which causes a change in electrical properties of this element, or of an additional member connected thereto, which is in turn connected to electrical connections. The change in electrical properties, e.g., conductivity, causes a change in the electrical signal emitted by the signal-generating device, thereby alerting receiving means, which receive this signal and detect the change, that inertial forces have been applied to the signal-generating device.

Such signal-generating devices have a variety of applications, for instance, in crash analysis, or in industry to analyze different dynamical behaviors of different moving parts, and for many other purposes which will be appreciated by the skilled engineer. A particular use is that described in the copending Israeli Patent Application No. 99836, filed October 23, 1991 by the same applicants herein, the description of which is incorporated herein by reference. In this case, the inertial signal-generating device is exploited in a brake lights activation system, to activate a circuit which causes the brake lights to light up when the acceleration pedal is suddenly released, and before the brake is actually actuated. In this particular use, the inertial signal-generating device detects the sudden and abrupt release of the pedal, 2020/91 -2- and generates a signal which is analyzed by appropriate electronic circuits.

Prior art devices suffer from a number of drawbacks. First of all, they are complicated in design and require the soldering of electric contacts on their inertial signal-generating element, or alternatively, other expensive and unsafe connections such as conductive glue, pins, spring contacts, electric connectors or the like. This leads to a high occurrence of failures in the devices, because of the unreliable connection. Furthermore, assembly of prior art devices is complicated and expensive, and requires highly trained manpower.

It is an object of the present invention to provide an inertial signal-generating device which overcomes the drawbacks of the devices of the prior art, and which is highly reliable and simple and inexpensive in construction.

The inertial signal-generating device according to the invention comprises a bendable basis onto which there is rigidly connected a bending sensor which changes its electric properties upon bending, the said bending sensor being provided with two electrodes positioned on its upper surface, electric contacts being provided in the signal-generating device to transmit the electric signal generated by the bending of the bending sensor to its destination, for further processing, the electric connection between the electrodes of the said bending sensor and the said electric contacts being effected by means of a Zebra conductor. By "Zebra conductor" is meant an element built of combined conductive and 2020/91 -3- non-conductive compressible material, such as Silicone Rubber. Preferably, such conductor is built of a plurality of layers, such layers being alternately conductive and non-conductive, so that electricity is transmitted only along the conductive layer. However, other arrangements comprising conductive zones embedded in non-conductive material are also contemplated by the invention. Such devices, which are normally in the shape of a block or cube, are well known in the art, and require no particular description. They can be made of a variety of material, e.g. rubber, in which case the conductive layers will be made - of conductive rubber, which is rubber that incorporates conductive material, such as graphite. An example of such connectors are the silicone rubber connectors made by You-Eal Corporation, Korea.

According to a preferred embodiment of the invention, the device comprises electric contacts provided in a roofing element, the distance of which from the electrodes of the bending sensor is smaller than the height of the Zebra conductor, which causes the said Zebra conductor to be in a compressed state whenever in the mounted position. This insures good and safe electric contact between the bending sensor and the electric contacts of the device.

The bending sensor can be of any appropriate type, and is preferably selected from a force-sensing resistor or a piezo-electric element or film.

As stated, the basis element on which the bending sensor is positioned must bend in order to cause a change in electric properties of the sensor. 2020/91 -4- This is caused by inertial forces when the device moves or stops suddenly, and this effect can be aided by providing a weight positioned at the extremity of the bending portion of the device, which weight may be integral with the bending portion, which can conveniently be made of plastic material, or can be connected to the bending element, e.g., to employ heavier material. Thus, for instance, a metal weight can be employed together with a plastic bending basis.

All the aforesaid and other characteristics and advantages of the invention will be better understood through the following illustrative and non-limitative description of preferred embodiments thereof, with reference to the appended drawings, wherein: - Fig. 1 is a partial cross-section of a perspective view of a device according to one embodiment of the invention; - Fig. 2 shows a latter cross-section of the device of Fig. 1; - Fig. 3 shows the device of Fig. 2 during bending; and - Fig. 4 is an exploded view of the device of Fig. 1.

In the figures, numeral 1 generally indicates the main body of the device according to the embodiment shown in the figures, to which there are connected a number of elements: the bendable basis 2, which may be integral with the main body 1, or may be connected thereto, in any appropriate way, and supporting elements 3 and 3', for the roofing contact element 4, which will be discussed later. Stopper means 5 can be connected either to basis 2, or to main element 1, or to both. Elements 1, 2, 3, 3' and 5 can of course also be made of one piece, e.g., by casting or moulding of a plastic material.

As is clearly seen in the figures, the bending sensor, 6, according to the embodiment shown in the figure, is made of a flat element onto which a film has been connected, which creates two electrodes, 7 and 7', which are both on the upper part of sensor 6. Sensor 6 is positioned in its correct position by providing stopper element 5, which limits its position with respect to the main body 1.

A Zebra connector 8 is provided, which is in contact with both electrodes 7 and 7'. However, because of its nature, only layers 9 and 9' (Fig. 2) will be in contact with electrode 7, while only layers 10 and 10' will be in contact with electrode 7'. On the other side of connector 8, on roofing element 4, appropriate electric contacts will be positioned so as to be in contact with the appropriate section of connector 8 (not shown in Fig. 2). This can be seen, e.g., in Fig. 4, in which roofing element 4, which can be, e.g., a printed circuit board, is seen to be provided with two contacts, 11 and 11', which are in turn connected by electric connections (not shown) to electric wires 12 and 12', which lead the signal to the appropriate analyzing means. The electric contacts 11 and 11', as well as their electric connections to wires 12 and 12', can be embedded in roofing element 4, or can be connected thereto and may be, e.g., strips of conducting materials, and the appropriate construction of these connections can be easily devised by the skilled engineer. 100197/2 -6- As is seen in the figures, and particularly in the exploded view of Fig. 4, roofing element 4 is connected to the device by sliding it into grooves 13 and 13' of elements 3 and 3', which will hold it in place in its assembled position. An additional weight 14 is provided, according to this embodiment of the invention, to promote bending of basis 2, which weight can be of any suitable material, depending on the specific density required of this weight.

Looking now at exploded view 4, the assembly of the inertial signal-generating device, according to this embodiment of the invention, is effected as follows. The bending sensor 6 is positioned on bending basis 2, until it stops at stopper 5. Connection between the bending element 6 and bending basis 2 must be thorough and rigid, and can be effected, e.g., by glueing. Next, Zebra connector 8 is positioned on bending sensor 6, in juxtaposition with the inner wall 1' of wall element 1, and then roofing element 4 is caused to slide into grooves 13 and 13' of elements 3 and 3', simultaneously applying a slight pressure on connector 8, so as to hold it tightly in place against bending sensor 6, and on electric contacts 11 and 11' positioned on the said roofing element. When this assemblage is concluded,weight element 14, if existing, can be assembled and can be kept in place by any convenient connecting element. Of course, wiring 15 is to be passed, according to this embodiment of the invention, through opening 16 in main body 1.

Of course, appropriate encasing of the sensor will be provided, to contain the sensor elements described above, which encasing can be of any 2020/91 -7- convenient shape and size, according to individual requirements of the end use, and which encasing is therefore not shown in the figures for the sake of brevity.

In Fig. 3 the device according to this preferred embodiment of the invention is seen in its bending state, and it is seen that its extremity, bearing the weight 14, is bending more strongly than its whole body, but such bending is sufficient in order to cause a bending of bending sensor 6. Depending on the type of sensor employed, the extent of bending can be important, or only the fact that some bending has taken place is sufficient to generate an appropriate signal.

Of course, the shape of the various elements shown in the figures is not essential, and can be changed according to design requirements and production as well as economic considerations, and the skilled engineer will easily devise a large number of different elements, leading to different looking inertial signal-generating devices. However, it is important to insure that the bending sensor is free to bend, and that the electric changes brought about by such bending are transmitted to a connecting element through an elastic connector, such as a Zebra connector, which elastic connector is held tightly in place against the electrodes, to insure effective and reliable electric contact, such Zebra connector will also be provided with insulating zones, as appropriate according to the specific use and shape of the electric contacts. In any case, all the modifications described above and other modifications, which can be carried out by the skilled engineer, will not depart from the spirit of this invention, and will not exceed its scope.

Claims (13)

2020/91 -8- CLAIMS: t

1. An inertial signal-generating device comprising a bendable basis^ onto which there is rigidly connected a bending sensor^which changes bending sensor being upper surface, electric contacts being provided in the signal-generating device to transmit the electric signal generated by the bending of the bending sensor to its destination, for further processing, the electric connection between the electrodes of the said bending sensor and the said electric contacts being effected by means of a Zebra conductor, $ as herein defined.

2. A device according to claim 1 , wherein the Zebra conductor is made of elastic material.

3. A device according to claim 2, wherein the elastic material comprises conductive rubber.

4. A device according to claim 2 or 3, wherein the Zebra conductor is in block form.

5. A device according to claim 4, wherein the Zebra connector comprises alternated insulating and conductive strips of elastic material.

6. A device according to any one of claims 1 to 5, wherein the distance between the electric contacts of the signal-generating device and the electrodes of the bending sensor is smaller than the height of the Zebra 2020/91 -9- conductor, thereby causing the said Zebra conductor to be in a compressed state when in the mounted position.

7. A device according to claim 6, wherein the electric contacts of the signal-generating device are positioned on a detachable roofing element which, when in the mounted position, applies a pressure on the Zebra conductor towards the electrodes of the bending sensor.

8. A device according to claim 7, wherein the roofing element is a printed circuit board.

9. A device according to any one of claims 1 to 8, wherein the bending sensor is selected from force-sensing resistors, or a piezo-electric element or film.

10. A device according to any one of claims 1 to 9, further comprising a weight positioned at or near the extremity of the bendable basis.

11. A device according to claim 10, wherein the weight is integral with the bendable basis.

12. A device according to claim 10, wherein the weight is connected to the bendable basis by means of appropriate connecting means.

13. An inertial signal-generating device, essentially as described and illustrated. l O M X JIM LU2ZATTO A LUZZATTO