GB2134714A

GB2134714A - Signal transmitter switch

Info

Publication number: GB2134714A
Application number: GB08334574A
Authority: GB
Inventors: Gregor Zeller; Helmut Bonn
Original assignee: Petri AG
Current assignee: Petri AG
Priority date: 1982-12-30
Filing date: 1983-12-29
Publication date: 1984-08-15
Also published as: FR2538944A1; FR2538944B1; GB8334574D0; DE3248607C2; GB2134714B; DE3248607A1; BR8307302A

Abstract

A signal transmitter switch for motor vehicles comprises metallic contact plates (6) (7) of which at least one plate (6) is provided with knubs (8) which extend towards the other plate in opening 10 in a soft-plastic moulded part (9) adhered to both plates, said moulded part (9) preferably being formed from polyurethane and having a thickness which exceeds the height of the knubs (8) by the required contact clearance. The counter contact (7) may be formed by the component carrying the signal transmitter, for example the steering wheel rim or the steering wheel spoke (3). The contact plate (6) may be cushioned against padding (12) by means of an insert (15) made of expanded plastics material. In the region of the contact plate, the padding (12) is provided with a keypad (16) which has finger recesses (17) in the region of the openings (10). <IMAGE>

Description

SPECIFICATION Signal transmitter The invention relates to a signal transmitter for motor vehicles, comprising a contact which is connected to the source of current and an earthed counter-contact.

Signal transmitters which are incorporated in a steering wheel spoke are known, such transmitters being generally formed by two plastics material parts kept spaced apart from each other by means of metal springs, and a contact plate is inserted into each of the plastics material parts to serve as a contact and counter contact respectively, and such plastics material parts are secured in a recess provided for this purpose in the steering wheel spoke. As a result, the signal transmitter forms a separate component which is visible on the steering wheel, but, because of the need to provide a large amount of padding, as protection for the driver in the event of an accident, it is difficult to incorporate the transmitter in the overall arrangement.

Signal transmitters are also known which comprise a contact plate and a counter contact plate, one plate being secured in the steering wheel spoke in the desired manner and the other plate being secured in a cover cap made from an appropriately rigid material, the whole of the cover cap forming the actuator and being mounted, for this purpose, on the steering wheel in such a manner as to be capable being depressed against the action of a spring by providing a gap all round.

The particular disadvantage of this type of arrangement for a signal transmitter is the need to use a cover cap made of rigid material whereas nowadays, for safety reasons, there is an overriding tendency to use materials which are as soft as possible for the padding of the steering wheel. Also, from the point of view of styling, the gap which is provided all round the cover cap is undesirable.

Finally, both known types of signal transmitters have the additional disadvantage in common that they require considerable manufacturing and assembly work. Both types of signal transmitters comprise a plurality of individual component parts which have to be manufactured individually and assembled, and finally - depending upon the type of construction of the signal transmitter they have to be mounted on the steering wheel either individually or together in an operation prior to the padding being applied to the steering wheel.

The present invention seeks to provide a signal transmitter for motor vehicles which is easy to manufacture and assemble and permits the steering wheel to be provided with a padding which presents a stylish uniform surface.

According to the present invention there is provided a signal transmitter for motor vehicles, comprising a contact which is connected to the source of current and an earthed counter countact, characterised in that the contact and the counter contact are each formed by a respective metallic plate of which at least one plate is provided with knubs which extend towards the other plate and which are interconnected by means of a softplastic moulded part adhered to both plates, said moulded part having a thickness which exceeds the height of the knubs by the required contact clearance and having openings in the region of the knubs.

The invention provides a signal transmitter which comprises only a few parts which can be easily manufactured, and such a signal transmitter may be fully incorporated in the padding, made of a soft material, polyurethane for example, by means of a moulding-in process. The number of operations needed to assemble the signal transmitter is considerably reduced, and the contact is "made" through the padding of soft material so that there is no need for the gap which was previously necessary around the actuator. As a result, the steering wheel can be manufactured in one working operation with a wide range of possible styles.

The contact plate and the counter contact plate may be connected to the source of voltage and earth, respectively, in a manner known Fer se by means of electrical conductors. In a preferred embodiment of the invention, however, the counter contact plate may be directly connected to the component carrying it, for example the steering wheelrim or the steering wheel spoke, as the earth connection, and the contact plate may be connected to the positive pole of a source of direct current by means of an electrical lead. In a further alternative development of this embodiment, the steering wheel rim or the steering wheel spoke itself may simultaneously form the counter contact and earth connection.

The adhesion of the contact plate to the opposite contact plate may be achieved in any desirable, known manner, but the use of doublesided adhesive inserts made of expanded plastics material is preferred because such inserts permit the contact plate to be very easily connected to the opposite contact plate or, respectively, the carrying part of the steering wheel. The inserts made of expanded plastics material are advantageously formed from foamed, opencellular polyurethane, the pores of which are sealed by means of adhesive, by welding, by a coating of film or by some other suitable means.

Because of the open-cellular structure, the contact pressure required is thus limited to a small amount, and the coating of adhesive or any other manner of sealing the pores prevents foam from entering the insert, such an insert not being allowed to harden because the foam is applied so as to encase said insert.

In cases where materials of relatively greater hardness are used as padding materials and/or pads of greater thickness, the contact plate may be cushioned against the padding by means of an insert made of expanded plastics material, whereby the switching resistance can be accordingly adapted according to circumstances, within specific limits. To improve the reliability of operation, it is also preferable to provide in the surface of the padding a keypad which is covered by the contact plate and has finger recesses which correspond with the knubs of the contact plate.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a fragmentary, partial view of a steering wheel provided with a signal transmitter; Fig. 2 is a sectional view through a signal transmitter; and Fig. 3 is a sectional view through another embodiment of a signal transmitter.

Fig. 1 of the drawings illustrates schematically a steering wheel which comprises, in detail, a steering wheel rim insert 1, a steering wheel rim covering 2, steering wheel spokes 3 and a hub cover 4. The steering wheel is provided with a signal transmitter which is generally referenced 5.

A contact 6 and a counter contact 7 are each formed by respective metallic plates, one of which, the contact plate 6, is provided with knubs 8 which extend towards the counter contact plate 7 and which are interconnected by means of a softplastic moulded part 9 adhered to both plates, said moulded part 9 having a thickness which exceeds the height of the knubs 8 by the required contact clearance and having openings 10 in the region of the knubs 8.

In the embodiment illustrated in Fig. 2, the counter contact plate 7 is adhered to the component carrying the signal transmitter, namely the steering wheel spoke 3, by means of a doublesided adhesive insert 11 made of expanded plastics material, and the contact plate 6 and the counter contact plate 7 are connected to a supply voltage and earth, respectively, by means of leads 13, 14. In the case of the embodiment shown in Fig. 3, however, the counter contact 7, or respectively the earth contact, may be formed by the steering wheel spoke 3, itself.

To compensate for the hardness of the padding in this latter embodiment, the contact plate 6 is cushioned against the padding 12 by means of an insert 1 5 made of expanded plastics material and, as with the moulded portion 9, said insert 1 5 is formed from foamed plastics material, preferably open-cellular or closed-cellular resilient material, the pores of which are sealed by means of adhesive, by welding, by a coating of film or by some other suitable means. In the region of the contact plate 6, the padding 12 is provided with a keypad 1 6 which has finger recesses 17 corresponding with the openings 10 in the insert 9 of expanded plastics material.

Claims

1. A signal transmitter for motor vehicles, comprising a contact which is connected to the source of current and an earthed counter contact, characterised in that the contact (6) and the counter contact (7) are each formed by a respective metallic plate, of which at least one plate (6) is provided with knubs (8) which extend towards the other plate (7) and which are interconnected by means of a soft-plastic moulded part (9) adhered to both plates, said moulded part (9) having a thickness which exceeds the height of the knubs by the required contact clearance and having openings (10) in the region of the knubs (8)

2.A signal transmitter as claimed in claim 1, in which the counter contact plate (7) adheres to the component carrying the signal transmitter by means of a double-sided adhesive insert (11) made of plastics material, and the contact plate (6) and the counter contact plate (7) are connected to a supply voltage and earth, respectively, by means of supply leads (1 3, 1 4).

3. A signal transmitter as claimed in claim 1 or 2, in which the counter contact plate (7) is connected to the steering wheel rim or the steering wheel spoke (3), and the contact plate (6) is connected to the supply voltage by means of a supply lead (13).

4. A signal transmitter as claimed in claim 3, in which the counter contact (7), or respectively the earth contact, is formed by the component carrying the signal transmitter, i.e. the steering wheel rim or the steering wheel spoke (3).

5. A signal transmitter as claimed in one of claims 1 to 4, in which the soft-plastic moulded parts (9, 11, 15) are formed from expanded, opencellular or closed-cellular resilient material, the pores of which are sealed by means of adhesive, by welding, by a coating of film or by some other suitable sealing means.

6. A signal transmitter as claimed in one of claims 1 to 5, in which the contact plate (6) is cushioned against the padding (12) by means of an insert (15) made of expanded plastics material.

7. A signal transmitter as claimed in one of claims 1 to 6, in which the padding (12) in the region of the contact plate (6) is provided with a keypad (16) which has finger recesses (17), or raised portions, in the region of the openings (10) in the insert (9) made of expanded plastics material.

8. A signal transmitter substantially as herein described with reference to and as illustrated in the accompanying drawings.