GB2322839A

GB2322839A - Motor vehicle anti-static earthing strip

Info

Publication number: GB2322839A
Application number: GB9704837A
Authority: GB
Inventors: Martin Kinross Saul
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-08
Filing date: 1997-03-08
Publication date: 1998-09-09
Also published as: GB9704837D0

Abstract

A motor vehicle having a metal body in which there are means on the interior of the vehicle body to enable a passenger seated within the vehicle body to contact the metal of the body before rising from their seat to disembark from the motor vehicle; whereby any static charge which has built up on the passenger's body will not cause an electric discharge between the passenger's hand and the vehicle body upon alighting from the vehicle. One way of achieving this is by means of an earthing strip 9 or wire which may be formed from a self-adhesive electrically conductive plastic sheet, connected between the interior component and the metal of the vehicle body.

Description

MOTOR VEHICLE ANTI-STATIC ARRANGEMENT This invention concerns a means of avoiding static electric shocks commonly experienced by drivers and/or passengers alighting from cars.

Car interiors are increasingly made of, or trimmed with a variety of plastic materials, and the upholstery is frequently made of synthetic fibres.

Many clothing fabrics are also made of synthetic fibres, or contain a significant proportion of synthetic fibres.

Movement of car occupants causes friction between the synthetic clothing fabrics and the upholstery and interior trim of the car, which generates a static electric charge.

In conditions of very low relative humidity this charge cannot dissipate from the highly insulating interior of the car.

A common but ineffective attempt to solve this problem has been the attachment of a flexible conductor to the rear underside of the car, which makes intermittent contact with the road.

Patent specification DE 44 22 133 Al is concerned with avoiding the build up of static charges particularly by the friction of air in the plastic ducts, but also mentions earthing to the road via a flexible conductor.

Experiments have shown that: In the right atmospheric conditions, a few seconds movement of a person wearing clothes containing synthetic or highly insulating fibres, on a car seat with synthetic upholstery, can generate a static electric charge which can discharge on contact between the person and the steel car door or body, causing an uncomfortable electric shock.

Earthing the car to the ground by means of a copper conductor and earthing pin driven into the soaked ground does not prevent the static electric shock mentioned above. This indicates that earthing to the ground is not relevant to the problem, and suggests that the problem arises from the potential differences between the steel car body and the person who has just alighted from the car.

It was found that if the occupants are electrically connected to the body of the car just before and at the moment of leaving the seat, no shock occurs on contact with the steel car body or door.

The purpose of this invention is to ensure that the occupants of a car are earthed to the body of the car as they leave the seat, so that any electrostatic charge is harmlessly drained to the car body, and no electric shock is experienced when the outside of the car is touched.

This may be achieved by ensuring that those parts of the car (generally the door) which an occupant may touch at the moment of leaving the car seat are electrically conductive and are electrically connected to the steel door panel or car body.

In particular, one or more of the following items numbered for identification on the drawings1 1, 2, and 3, should be made electrically conductive, and should be electrically connected to the steel door panel or car body.

1. The door release lever. Item (1) in drawing 1.

2. A handrest or handle, conveniently positioned for pushing the door open whilst leaving the seat. Item (2) drawing 1 3. A handle or door pull, also conveniently positioned for opening the door while leaving the seat. Item (3) in drawing 1.

4. Trim member under window, formed or textured to provide a comfortable hand rest in any position across the width of the door.

Item (4) in drawing 1.

5. Trim member under window, formed with a finger recess along the top edge to provide a comfortable hand rest in any position across the width of the door. Item (5) in drawing 2.

6. Finger plate. Item (6) in drawing 2. (Alternative to (4) or (5) above).

7. Arm rest Item (7) in drawing 1.

8. Handles fixed adjacent to the door, in any convenient position to provide support to an occupant leaving the seat. Item (8) in drawing 2.

9. A shape formed from self-adhesive electrically conductive plastic sheet, Item ( 9) drawing 3, with an integral conductor in secure contact with steel door panel Item ( 10) in drawing 3. (This is particularly suitable for fitting after manufacture) In the case of a car adapted for use by a disabled driver or passenger, the arm rest and any other additional grab rails, hand rests or supports specially provided or adapted to assist a person transferring from the car to a wheelchair, should be made electrically conductive and electrically connected to the steel door panel or car body.

For items (1) -(7) above, the connection to the steel door or car body panel may be achieved by means of an earthing strap or wire from a terminal on the item to a terminal on the steel panel.

Items which extend to the edge of the trimmed area of the door may be fixed directly in contact with the inner part of the steel door panel e.g. items (2), (4) or (5).

Item (8) may be fixed directly to the inner part of the steel body, or connected to it by means of an earthing strap or wire from a terminal on the item, to a terminal on the steel panel.

Item (I) which is linked to the door release mechanism item (11) in drawing 1, by a system of bent wire links, located or spaced by plastic bushes or links, could be electrically connected to the steel door panel by forming the bushes or links from electrically conductive plastic.

If the material from which any of the items (1-7) are made is highly conductive, it may be necessary to introduce a resistance into the connection to the steel body panel, to ensure a steady drain of the static electric charge, rather than a rapid discharge which could cause discomfort. Such resistance could be introduced by the use of connectors formed as drawing 4, in partially conductive plastic, such that the end (a) mates with a conventional spade terminal, on the conductor from the item (1)-(7) and the end (b) is formed as a convenient fixing on the steel panel.

Claims

1. A motor road vehicle having a metal body in which there are means on the interior of the vehicle body to enable a passenger seated within the vehicle body to contact the metal of the body before the passenger rises from their seat to disembark from the motor vehicle whereby any static charge which has built up on the passenger's body wiil not cause an electrical discharge between the passenger's hand and the vehicle body upon alighting from the vehicle and closing the door.

2. A motor road vehicle body as claimed in Claim 1, in which the said means comprises a self adhesive electrically conductive lamina member adapted to be secured to the interior door trim of the vehicle body and to be electrically connected to the metal car body.

3. A motor road vehicle body having any of the arrangements described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A motor road vehicle having a metal body in which a self-adhesive electrically conductive lamina member is mounted on the interior of the vehidle body and is electrically connected to the vehicle body to enable a passenger seated within the vehicle body to contact the metal of the body before the passenger arises from their seat to disembark from the motor vehicle whereby any static charge which has built up on the passenger's body would not cause an electrical discharge between the passenger's hand and the vehicle body upon alighting from the vehicle and closing the door.

2. A self-adhesive electrically conductive lamina member for use in the arrangement of Claim 1.