GB2030367A

GB2030367A - Vehicle Steering Wheel and Steering Wheel Cover

Info

Publication number: GB2030367A
Application number: GB7930486A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-09-05
Filing date: 1979-09-03
Publication date: 1980-04-02

Abstract

In order to give an audible fatigue danger warning to vehicle drivers in conditions wherein there may be risk of fatigue leading to sleep or to dangerous inattention, a switch in a vehicle steering wheel or steering wheel cover maintains an audible warning device in an inactive condition whilst the switch remains operated. For this purpose, the steering wheel or steering wheel cover includes a pair of radially separated layers (14) and (18) of material of which the facing surfaces are electrically conductive, the radial separation being maintained by an insulating layer (16) which, when compressed, permits electrical contact between the two conductive surfaces. The electric switch thus formed is employed via suitable electric circuitry to actuate a warning device should the driver relax to the point where the electrically conductive surfaces separate. If the core 12 of the steering wheel is conductive the layer 14 may be omitted. <IMAGE>

Description

SPECIFICATION Vehicle Steering Wheel and Steering Wheel Cover This invention concerns a steering wheel and a steering wheel cover for a vehicle. More particularly it concerns an anti-sleep device for preventing a driver of the vehicle from falling asleep.

Long distance lorry drivers, and any other drivers who set out on long journeys in their vehicles, must be careul that they do not fall asleep whilst driving. This is particularly true on motorways and the like where the driving operation is minimal and the danger of falling asleep greatest.

While it is impossible to estimate accurately how many accidents are caused each year by the driver of at least one vehicle falling asleep, it is often felt that many accidents do occur for this reason. Furthermore, there is medical evidence to suggest that, during the process of falling asleep, a driver's muscles relax and consequently his grip on the steering wheel of the vehicle also relaxes.

It is an object of this invention therefore to attempt to reduce the number of accidents which are caused in the aforementioned way by providing a safety device for a vehicle which warns a driver when his grip on the steering wheel relaxes.

According to the present invention there is provided a vehicle steering wheel cover adapted to fit circumferentially over and around the rim of a vehicle steering wheel and including a plurality of radially superimposed layers, of which three adjacent layers comprise or have arcuate sections which comprise a pair of opposed, radially spaced electro conductive surfaces separated by a resilient electrically insulating medium formed with apertures serving to permit electrical contact between said surfaces whenever the layers carrying the same are compressed radially towards one another, and electrical connector or terminal means on or in said cover for enabling said electro conductive surfaces to be employed as an electric switch.

Conveniently, the insulating medium is a framed plastics material and maintains the inner and outer layers separated when the outer layer is subjected to inwardly directed pressure below a predetermined minimum but being arranged such that the two layers come into electrical contact when the outer layer is subjected to a pressure above said predetermined minimum. The electrical switch is arranged to activate an audible warning device when there is no electrical contact between the inner and outer layers.

A device in accordance with this invention therefore may help prevent accidents by warning a driver that his grip on the steering wheel is too relaxed, which is either because the driver is falling asleep or because he is not holding the steering wheel properly.

Conveniently, the hazard warning lights of the vehicle may be connected in parallel with the audible warning device so that other road users are aware of some danger and are on their guard against sudden or gradual changes in the course of the vehicle concerned.

The electro conductive layers in the steering wheel cover preferably comprise plastics sheet coated with electro conductive material. The insulating layer is preferably resilient plastics foam having a plurality of apertures therethrough.

The invention is further described hereinafter, by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a fragmentary perspective view of part of a steering wheel which carries a safety device in accordance with this invention; and Fig. 2 is a circuit diagram of electrical circuitry which accompanies the device of Fig. 1.

One embodiment of the invention is described with reference to Fig. 1 which shows part of a steering wheel 10 of a motor vehicle (not shown).

The steering wheel comprises a core 12 and four outer layers 14, 16, 18, 20 whose function is hereinafter explained. The inner layer 14 is juxtaposed with the core 12 and comprises a flexible material which is either electrically conductive or has a conductive layer applied thereto. In the illustrated embodiment, the safety device may be supplied separately from the vehicle and incorporates switch means in the form of a steering wheel cover which is subsequently fitted on to the steering wheel. The steering wheel is not necessarily specifically constructed for the application of the safety device of the invention and the wheel may be of any size or constructed from any material.

Steering wheel covers of different sizes and shapes may easily be made to allow for the former contingency but, because of the possible constructional materials which may be used in a steering wheel, the inner layer 14 is normally arranged to be insulated from the steering wheel to allow for the case where the wheel itself is metallic and hence electro conductive. In a preferred embodiment a layer 14 comprising a plastics material sheet which is coated on its outer surface only, with an electro-conductive substance, is found to be most suitable. The result is an electro conductive layer 14 around the core of the steering wheel. At some point around the circumference of the steering wheel; but preferably in the region of a radial support of the steering wheel, an insulated electrical lead 22 is taken from the layer 14 and connected to the circuit 100 illustrated in Fig. 2.

An electrically insulating layer 1 6 is juxtaposed with the layer 14 and normally serves to insulate the latter from the layer 1 8. The material chosen for the layer 1 6 must however serve another purpose; that is, when light manual pressure is applied on the layer 1 8 towards the center of the core 12, the insulating properties of layer 1 6 must be rendered temporarily inoperative and permit electrical contact to be established between the two layers 14, 18. When the light manual pressure is relaxed, the insulating properties of the layer 16 must, however, be restored.

Such properties may be supplied by a suitable gas or a liquid constituting the layer 1 6 but a preferred material is a resilient foam rubber or plastics material which has a plurality of apertures formed therein. Thus, when pressure is applied to the layer 18, electrical contact can be established between the two layers 14, 1 8 through the apertures, but when the pressure is relaxed the resilience of the foam separates the two layers.

Layer 18 is a duplicate of layer 14, except that the electro-conductive coating is on the inside.

Again, a suitably coated plastics material may be used although an impregnated cloth may equally well be suitable. Extending from the electroconductive region of layer 18 is a second insulated lead 24 which is also connected to the circuit 100 and which preferably leaves the device adjacent the lead 22.

Finally, the layer 20 covers all the previous layers and may be constructed of leather or other material appropriate to the manual handling experienced by steering wheel covers. The layer 20 may, if desired, fulfil the function of layer 18, so that the latter could be omitted. In this event, the electro-conductive coating would be applied to the underside of the layer 20.

Alternatively however, if the steering wheel is electro-conductive the wheel could be arranged to take over the function of the layer 14 so that this layer could be dispensed with entirely.

If the invention is to be applied to a steering wheel cover which is to be sold separately from the vehicle then, when fitted, it has a C-shaped cross section with the open part on the inside of the steering wheel rim. The cover may be fitted and secured to the steering wheel by any of a variety of known methods. As the circuit 100, whose function is described herein below, is separate from the steering wheel, provision is made for allowing the wheel to be rotated without being impeded by the leads 22 and 24. In order to do this the leads 22, 24 may be coiled and made of a sufficient length to allow them to be twisted about the steering column as the steering wheel is turned.

Alternatively the invention may be directly applied to a vehicle during its manufacture. In this event the layers 14, 16, 18, 20, unless any are omitted, may be directly applied and secured to the steering wheel. They would then have a substantially O-shaped or other closed cross section in common with the steering wheel itself, with the outer layer 20 constituting the major part of the surface area of the steering wheel. The problem of turning the steering wheel without hindrance by the leads 22, 24 still applies however, although slip rings built into the steering column may be substituted for separate, external electrical leads. If the steering column is hollow, as it is in many vehicles, the leads 22, 24 or their equivalent may most conveniently be threaded therethrough.

Illustrated in Fig. 2 is the circuit 100 which activates the audible warning provided by the safety device of this invention. The device illustrated in Fig. 1 serves as a switch and is diagrammatically represented in Fig. 2 by the switch 110. The leads 22, 24 are also shown in Fig. 2 and are indicated by the reference numerals 122, 124 respectively. The lead 124 is connected directly to a power source 132, but preferably to the earthed terminal of the vehicle battery. The lead 122 is connected to a terminal of a relay switch 126, the other terminal thereof being connected, by a lead 128 and via a master switch 130, to the live terminal of the vehicle battery.

When the relay 126 is activated, that is energized by the power source 132, it opens a normally closed relay switch 134. Connected in series with the switch 134 is the master switch 130, and a lead 1 38 to which is connected one terminal of an audio warning device 136. The other terminal of the latter is connected via a line 140 to the earthed terminal of the power supply 132.

The mode of operation of the aforementioned circuit is further described hereinbelow. When a driver of a vehicle in which a safety device in accordance with this invention is fitted, begins a long journey, he closes the master switch 130.

Under less demanding driving conditions, however, as on a shorter journey, the driver may prefer to leave the switch 130 open; in which case the whole circuit is deactivated and the safety device is inoperative. A warning lamp 144 shown in Fig. 2 may be provided in the electrical circuit. As shown the lamp is illuminated when the master switch 130 is open, to indicate to the driver that the safety device is switched out of circuit. On a long journey, with the switch 130 closed the driver grips the steering wheel, and so closes the switch 110 in the manner described with reference to Fig. 1. With the switches 130, 110 closed the relay 126 is energised and the switch 134 is opened.

On a long journey, the danger exists that the driver may fall asleep; less immediately dangerous, but potentially highly dangerous, he may cease to grip the steering wheel sufficiently firmly and merely let his arm rest on the wheel or on a support arm thereof, or otherwise not hold the wheel properly. In either event, unless some extraneous factor occurs, for example, the driver falling across the wheel in his sleep, the switch 110 opens and the power supply to the relay 126 is cut off. Upon release of the relay, the switch 134 closes and so connects the audio warning device 136 across the power supply. The driver may then be sufficiently woken up to continue driving or at least be reminded to grip the steering wheel properly. The terminals 142, connected in parallel with the audio warning device 136, may serve to activate a separate warning system or even the hazard warning lights of the vehicle itself Thus, other road users may be warned that a sleeping or insufficiently alert driver is in the vehicle concerned.

Instead of the relay 126 a switching transistor might equally well be applied. In either event, if the circuit comprising the relay 126, lines 122, 124 and switch 110 should fail the switch 134 or its equivalent will close and the driver is warned that something is wrong; i.e. the circuit is fail safe.

In a preferred embodiment of this invention the steering wheel is metallic, for example an aluminium alloy, and the first layer is an insulating layer corresponding to the layer 1 6. On top of this is the outside cover whose inner surface is coated with electroconductive material. Thus only two layers are required. Furthermore, if the steering wheel is metallic and serves as one of the two conductive layers, only one slip ring is necessary as the steering wheel and column may then serve as the earth connector.

Claims

1. A vehicle steering wheel cover adapted to fit circumferentially over and around the rim of a vehicle steering wheel and including a plurality of radially superimposed layers, of which three adjacent layers comprise or have arcuate sections which comprise a pair of opposed, radially spaced electro-conductive surfaces separated by a resilient electrically insulating medium formed with apertures serving to permit electrical contact between said surfaces whenever the layers carrying the same are compressed radially towards one another, and electrical connector or terminal means on or in said cover for enabling said electro-conductive surfaces to be employed as an electric switch.

2. A steering wheel cover as claimed in claim 1, in which the electrically insulating medium is a foamed plastics material.

3. A steering wheel cover as claimed in claim 1, or claim 2, in which the layer on each side of the electrically insulating medium is a plastics material having one surface coated with an electro-conductive medium.

4. A steering wheel cover as claimed in any one of claims 1 to 3, in which all the layers are circumferentially continuous.

5. A steering wheel cover as claimed in any one of claims 1 to 4, in which the radially outer one of said three adjacent layers is itself covered by an outer cover of leather or other material appropriate to the manual handling required of said cover.

6. A steering wheel cover as claimed in any one of claims 1 to 4, in which the radially outer one of said three adjacent layers is the outermost layer of said cover.

7. A steering wheel cover as claimed in any one of claims 1 to 6, in which the radially inner one of said three adjacent layers is the innermost layer of said cover.

8. A vehicle steering wheel having a rim of circular or other circumferentially closed configuration, said rim comprising a core and a cover as claimed in any one of the preceding claims permanently united to said core.

9. A modification of the steering wheel claimed in claim 8, in which the core is metallic and replaces the radially innermost one of said layers.

10. Vehicle safety apparatus comprising an audible warning device, electric circuitry controlling operation of said audible warning device and a steering wheel cover or steering wheel as respectively claimed in any one of the preceding claims, said electric circuitry including a relay having a normally closed pair of switch contacts connected in a power supply to said audible warning device and the electric switch of said steering wheel cover or steering wheel being connected in series with the relay energising path to maintain said relay energised and the normally closed relay switch contacts open whenever said electro conductive surfaces are pressed together.

11. A vehicle steering wheel or steering wheel cover constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

12. Vehicle safety apparatus including a steering wheel or steering wheel cover as claimed in claim 11 and constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.