GB2129044A

GB2129044A - Safety latch

Info

Publication number: GB2129044A
Application number: GB8327340A
Authority: GB
Inventors: Brian Wigley; John Stephen Johnson
Original assignee: MOTOR VEHICLE SECURITY SYSTEMS
Current assignee: MOTOR VEHICLE SECURITY SYSTEMS
Priority date: 1982-10-12
Filing date: 1983-10-12
Publication date: 1984-05-10
Also published as: GB8327340D0; GB2129044B

Abstract

Motor vehicle safety means intended to prevent unauthorised opening of the doors of the passenger compartment of the motor vehicle while the vehicle is in motion comprises means for sensing motion of the motor vehicle and means controlled by the sensing means for disabling a door latch of the motor vehicle. The sensing means may comprise a castellated ferro-magnetic disc 10 arranged for rotation with the propeller shaft 12 of the motor vehicle, rotation of the disc being sensed by a stationarily mounted proximity sensor 11. Preferably the disabling means is also actuated by the braking system 14 of the motor vehicle. The disabling means may comprise a solenoid 1, 2 having a movable member 3 arranged to block operation of the interior door handle mechanism 5. <IMAGE>

Description

SPECIFICATION Safety latch The invention relates to safety means for disabling the door locks of motor vehicles. More particularly the invention relates to means for preventing the doors of motor vehicles from being opened from inside a passenger compartment of the vehicle while the vehicle is in motion. A number of serious accidents, often involving children, have occurred due to their having opened the doors of passenger compartments of motor vehicles in which they were travelling, e.g. the rear doors of taxis, while the vehicles were in motion. It is an object of the invention to provide means whereby such accidents may be avoided, which means does not unduly impede authorised entry and exit from the vehicle.

According to the invention there is provided means for sensing motion of the motor vehicle and means controlled by the sensing means for disabling a door latch of the motor vehicle. The sensing means may comprise means for sensing rotation of a rotating member secured to or forming part of the motor vehicle transmission e.g.

the motor vehicle propeller shaft or a road wheel.

We prefer however to insert a castellated mild steel disc at one end of the propeller shaft, rotation of which is sensed by a stationarily mounted proximity sensor which may be magnetically actuated. Alternatively the motion sensing means may be driven from the motor vehicle speedometer, this being particularly convenient where the speedometer is of the electronic variety.

Preferably the arrangement is such that at least one of the door latches of the motor vehicle is disabled to prevent opening of the door from the interior of the motor vehicle when the sensor detects that the vehicle is in motion and we prefer that the control circuitry includes delay means whereby the disabling continues for a period of time, e.g. two seconds, after the vehicle has come to rest. Advantageously the arrangement is such that the braking system of the motor vehicle is also effective e.g. by means of a hydraulic pressure sensitive switch; to energise the disabling means for the door latches for example to cover the possibility of the doors being opened when the vehicle is in motion but its wheels are stationary as for example when the vehicle is in a skid condition, and also for the situation that the vehicle is stationary in traffic.Thus the driver of the motor vehicle can disable the interior door latches by depressing the brake pedal of the motor vehicle. We prefer that the disabling means comprises a solenoid having a movable member arranged to block operation of the interior door handle, and preferably the arrangement is such that the doors can be opened from the exterior whether or not the solenoid is actuated.

The invention is diagrammatically illustrated by way of example in the accompanying drawings in which: Figure 1 shows the various parts of the locking means and shows the vehicle in the stationary condition with the ignition switched off: Figure 2 is a view similar to that of Figure 1 and showing the ignition switched on with the vehicle stationary; Figure 3 is a view similar to that of Figure 1 but showing the ignition on with the vehicle stationary and the foot brake applied; Figure 4 is a view similar to that of Figure 1 with the ignition on and the vehicle in motion; Figure 5 is a view similar to that of Figure 1 and showing the ignition on, the vehicle in motion and decelerating with the foot brake applied; Figure 6 is a front view of part of a motion sensor; Figure 7 is a scrap view on an enlarged scale of door lock disabling means, showing the means deactivated; and Figure 8 is a scrap view similar to that of Figure 7 but showing the disabling means in its operative state.

In the drawings there is shown safety means for disabling door locks of motor vehicles, e.g. motor taxis, these safety means comprising solenoids 1 and 2 associated with the right hand and left hand doors respectively of the passenger compartment of the motor vehicle, the solenoids being mounted in the respective doors of the passenger compartment and being arranged to control the motion of a blocking member 3 disposed on the free end of a pivoted arm 4. The arrangement is such that when the solenoid is de-energised the arm falls by gravity into the position shown in Figure 7 whereas when the solenoid is energised the arm assumes the position shown in Figure 8. In this position motion of a handle bar 5 to the left as viewed in the drawing and to unlatch the door of the motor vehicle is prevented by the interposition of the blocking member 3.In conventional fashion the handle bar 5 is actuated by an interior door handle not shown and the associated exterior door handles are coupled so that they are unaffected by the safety means to permit access to the vehicle irrespective of the operation of the safety means.

The solenoids 1 and 2 are energised from the electrical system of the motor vehicle through an electronics control box 6 connected to the ignition switch 7 of the motor vehicle, activation of the control box being indicated by a warning lamp 8.

Power is supplied to the solenoids when a proximity sensor 9 detects that the vehicle is in motion in the manner described below or when the foot brake 1 6 is depressed.

The proximity sensor 9 comprises a ferro magnetic castellated disc 10 coupled between the motor vehicle gear box 12 and its associated propeller shaft 1 3 so as to rotate with the propeller shaft 1 3. Rotation of the sensor disc 10 is detected by a proximity sensor 11 stationarily mounted adjacent to the disc 10 on the gear box tail shaft 12. Pulses from the proximity sensor are fed to the control box 6 to cause actuation of the solenoids.

The brake master cylinder 14 of the motor vehicle is provided with an electrical switch 1 5 sensitive to hydraulic pressure in the braking system so that on depression of the foot pedal 16 of the braking system a signal is fed to the control box 6 to cause actuation of the door solenoids.

In Figure 1 of the drawings the apparatus is shown in the de-activated condition with the motor vehicle ignition off and the vehicle stationary. In this condition the solenoids are in their inoperative position.

In Figure 2 of the drawings the ignition is shown switched on to energise the control box so that the warning lamp 8 glows. Since the vehicle is stationary and the foot brake is not applied the solenoids are still de-activated.

In Figure 3 of the drawings the vehicle is shown stationary but with the foot brake applied so that the control box is activated to cause the solenoids to be energised to disable the door locks.

In Figure 4 of the drawings the vehicle is shown in motion so that the proximity sensor energises the control box to cause the solenoids to move the blocking members 3 into their operative position to disable the door locks.

In Figure 5 of the drawings the control box is energised both by the foot brake and by the detection of motion by the proximity sensor so that again the door locks are disabled.

Claims

1. Motor vehicle safety means comprising means for sensing motion of the motor vehicle and means controlled by the sensing means for disabling a door latch of the motor vehicle.

2. Motor vehicle safety means according to claim 1, wherein the sensing means comprises means for sensing rotation of a rotating member secured to or forming part of the motor vehicle power transmission.

3. Motor vehicle safety means according to claim 2, wherein the sensing means comprises a castellated ferro-magnetic disc arranged for rotation with the propeller shaft of the motor vehicle, rotation of the disc being sensed by a stationarily mounted proximity sensor.

4. Motor vehicle safety means according to any preceding claim, wherein the disabling means is such that a door latch of the motor vehicle is disabled to prevent opening of a vehicle door from the interior of the motor vehicle when the sensor detects that the vehicle is in motion.

5. Motor vehicle safety means according to any preceding claim, wherein the sensing means comprises control circuitry including delay means whereby disabling of the door lock continues for a period of time after the vehicle has come to rest.

6. Motor vehicle safety means according to any preceding claim, wherein the disabling means is actuated by the braking system of the motor vehicle.

7. Motor vehicle safety means according to any preceding claim, wherein the disabling means comprises a solenoid having a movable member arranged to block operation of the interior door handle.

8. Motor vehicle safety means according to claim 7, wherein the movable member is biased into an inoperative position.

9. Motor vehicle safety means according to claim 8, wherein the movable member is gravity biased.

10. Motor vehicle safety means substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

11. A motor vehicle comprising safety means claimed in any preceding claim.