GB2107909A

GB2107909A - Bumper assembly

Info

Publication number: GB2107909A
Application number: GB08225652A
Authority: GB
Inventors: Frederick John Charles Hope; James Malcolm Pigney
Original assignee: HOPE TECH DEV Ltd; HOPE TECHNICAL DEVELOPMENTS Ltd
Current assignee: HOPE TECH DEV Ltd; HOPE TECHNICAL DEVELOPMENTS Ltd
Priority date: 1981-09-10
Filing date: 1982-09-08
Publication date: 1983-05-05
Also published as: GB2107909B

Abstract

A bumper assembly for a road vehicle comprises a beam 1 which is supported by two arms 2 from the vehicle so that the beam is displaceable from a rest position in a direction towards or beneath the vehicle in the event of contact with an obstacle. A spring 9 is associated with each of the arms 2 for biasing the beam 1 towards its rest position. Sensing means 13, 14 is provided for detecting displacement of the beam 1 and activating a warning device. <IMAGE>

Description

SPECIFICATION Bumper assembly This invention relates to a bumber assembly for a road vehicle such as a rigid or articulated lorry, a passenger coach, a bus or a van.

Because of accidents involving vehicles with high ground clearance, it has been recommended practice to fit a rigid bumper bar to such vehicles so as to prevent smaller vehicles such as passenger cars from being forced underneath the larger vehicles in an accident. Legislation will shortly be enacted to require vehicles of a certain minimum weight to be fitted with such rigid bumper bars at a specified height beneath the rear of the vehicle.

Unfortunately such rigid bumper assemblies often cause damage when the driver is manoeuvring the vehicle in restricted spaces.

There is, therefore, a need for a bumper assembly which both meets the coming legal requirements and at the same time, does not increase the risk of accidental damage during operation of the vehicle.

The present invention provides a road vehicle having a bumper assembly fitted thereto, the bumper assembly comprising a beam which is supported by an arm from the vehicle so that the beam is displaceable from a rest position in a direction towards or beneath the vehicle in the event of contact with an obstacle, spring means for biasing the beam towards its rest position, and sensing means capable of detecting displacement of the beam and activating a warning device.

Thus, when the vehicle is being manoeuvred in restricted conditions, the bumper assembly is likely to be the first part of the vehicle which touches an obstacle; and, after being displaced a short distance (which will not damage the obstacle or the vehicle), a sound or visual warning will be activated so that the driver will be immediately aware that his vehicle is in contact with an obstacle. Preferably, the warning device is in proximity to the driving position.

In general, the beam will be displaceable through a predetermined distance. Thus, in the event of collision with another vehicle, there will be a deceleration effect during which the spring means of the bumper assembly will absorb some of the energy of impact. Thereafter, the beam will meet a stop position on the vehicle, which will prevent a smaller vehicle from penetrating beneath the larger vehicle.

Advantageously, the sensing means is a proximity switch, such as a Reed switch, one component of which is attached to the bumper assembly and the other to the vehicle.

Alternatively, the proximity switch is constituted by a pneumatic valve and an actuating device. In this case the pneumatic valve may be positioned in a line leading from a pressurised air reservoir to a horn, the horn constituting the warning device.

In one preferred embodiment, the bumper assembly includes a rod pivotally connected to the beam or to the arm, and the free end of the rod carries a component of the proximity switch.

Where the proximity switch includes a pneumatic valve, the actuating device may be a bent plate carried by the free end portion of the rod.

Preferably, the rod is connected to a hollow rubber spring which consitutes the spring means.

One-disadvantage of this bumper assembly is its susceptibility to damage when the vehicle moves over surfaces of changing inciine. In particular, when a vehicle leaves a ferry it travels down an inclined ramp and then up an inclined road surface. At the junction of the two inclined surfaces, the bumper assembly tends to hit the ground, and this can damage the bumper assembly.

In a preferred embodiment of the invention, therefore, the rest position is defined by a latch assembly, the latch assembly being such as to prevent the beam being displaced in a direction opposed to said direction, unless the beam is subjected to a pre-determined force.

Thus, if the bumper assembly catches on an obstruction, the whole assembly can pivot away from the vehicle upon the latch assembly being released.

Advantageously, the spring means is a hollow rubber spring which is mounted on a rod and positioned between a pair of retaining plates.

Preferably, one of the retaining plates is fixed to the arm, the other retaining plate being pivotally connected to the arm by means of a pivot bolt which also constitutes the pivotal connection between the arm and the vehicle. Conveniently, the latch assembly is constituted by a springbiased plunger mounted on the vehicle and by the other retaining plate.

Preferably, the beam is supported by a pair of arms, a respective spring means being associated with each of the arms, and a respective sensing means being associated with each of the arms.

The invention also provides a road vehicle having a bumper assembly fitted thereto, the bumper assembly comprising a beam which is pivotally supported by an arm from the vehicle so that the beam is displaceable from a rest position in a first direction towards or beneath the vehicle in the event of contact with an obstacle, and spring means for biasing the beam towards its rest position, wherein the rest position is defined by a latch assembly, the latch assembly being such as to prevent the beam being displaced in a direction opposed to said first direction, unless the beam is subjected to a predetermined force.

Two forms of bumper assembly, each of which is constructed in accordance with the invention, will now be described, by way of example, with reference to the accompanying drawings, in which Fig. 1 is a part-sectional elevation of a first form of bumper assembly, and shows part of the rear of a road vehicle to which the bumper assembly is attached; Fig. 2 is a view, partly in section, in the direction of the arrow A in Fig. 1; and Fig. 3 is a part-sectional elevation of a second form of bumper assembly, and shows part of the rear of a road vehicle to which the bumper assembly is attached.

Referring to the drawings, Fig. 1 shows a bumper assembly comprising a longitudinal beam 1 which is supported by two arms 2 (only one of which can be seen in Fig. 1) from a mounting channel 3 fixed to the chassis 4 of the vehicle.

The beam 1 is arranged to extend substantially across the entire width of the vehicle. As can be seen best in Fig. 2, each of the arms 2 is connected to a respective tube 5 which is pivotally mounted on a respective shaft 6. Each shaft 6 is supported in a respective housing 7 which is attached to the mounting channel 3.

In use, each of the arms 2 is displaceable from the position shown in Fig. 1 to a position where it abuts against a fabricated box member 8. Radial movement of each of the arms 2 is resisted by a respective hollow rubber spring 9 such as one manufactured by Aeon Limited. Pivotable movement of each arm 2 is transmitted to its spring 9 by means of a respective rod 10 which is pivotally connected, at 11, to the associated arm 2. As shown, each rod 10 carries a compression plate 11, passes through its spring 9, and has an elongated free end 12. The free end 12 of each rod 10 carries one component 13 of a Reed switch. In the arrangement shown, this component 13 is a magnet which co-operates with the other component 14 of the Reed switch.

As will be appreciated, when each of the arms 2 is displaced in the direction of the arrow X, its rod 10 will move in the direction of the arrow Y, and a predetermined movement in this direction will activate the Reed switch. The Reed switch is connected, via wiring (not shown), to a warning device in the driver's cab, which may be a flashing light on the panel or a buzzer or other audible warning device in the cab. If desired, the sensing device may also be connected directly to the vehicle brakes so as to apply emergency braking to the vehicle.

Instead of a Reed switch, a solid state switch of the kind known as a "Hall Effect Switch" may be used as the proximity switch. A "Hall Effect Switch" is a semi-conductor proximity switch which utilises the "Hall Effect" to give a variable output proportibnal to the strength of a magnetic field to which the switch is subjected.

The warning device may be a horn positioned adjacent to one of the springs 9. In this case, the horn is connected to an air reservoir by a line containing a pneumatic valve. The pneumatic valve is arranged to be opened (by a bent plate carried by the free end 12 of the rod 10 associated with that spring 9) when the rod is moved through a predetermined distance. In this case, the bent plate and the pneumatic valve take the place of the Reed switch or other proximity switch. Obviously, a similar arrangement may be associated with the spring 9 of the other arm 2. In either case, it is preferable to include a further valve in the or each line leading from the air reservoir, so that the pressure in the air reservoir cannot drop below a predetermined minimum pressure of say 80 p.s.i.

Fig. 3 shows a rear bumper assembly which comprises a longitudinal beam 21 which is supported by two arms 22 (only one of which can be seen in the drawing) from a mounting channel 23 fixed to the chassis 24 of the vehicle. The beam 21 is arranged to extend substantilly across the entire width of the vehicle. Each of the arms 22 is pivotally connected to the mounting channel 23 by means of a respective pivot bolt 23. Each of the arms 22 is provided with a forwardlyextending flange 26 which carries a lower retaining plate 27. An upper retaining plate 28 is associated with each of the lower retaining plates 27, each pair of retaining plates sandwiching a hollow rubber spring 29, such as one manufactured by Aeon Limited.Each of the upper retaining plates 28 is provided with a pair of upwardly-extending flanges 28a by means of which the retaining plate is pivotally attached to the associated arm 22 by means of the corresponding pivot bolt 25. Each of the upper retaining plates 28 is also provided with a pair of upwardly-extending flanges 28b. The flanges 28b constitute a stop defining the normal working position of the bumper assembly. In this position, in which the arms 22 and the beam 21 are shown in full lines in the drawing, the flanges 28b rest against the underneath side of the mounting channel 23.

A rod 30 passes through each of the springs 29, one end of each rod being pivotally attached to the associated pair of flanges 28b by means of a pivot bolt 31. Each of the rods passes through respective apertures in the corresponding upper and lower retaining plates 28 and 27, and the free end thereof projects beneath the lower retaining plate. The free end of each of the rods 29 is screw-threaded, so that the springs 29 can be pre-tensioned by means of nuts 32.

The front edge of each of the upper retaining plates 28 forms part of a respective latch assembly, the latch assemblies being used to hold the bumper assembly in its normal working position unless a large force is applied to the beam 21 in the direction of the arrow A. Each of the latch assemblies is completed by means of a respective plunger assembly (only one of which is shown in the drawing). Each plunger assembly has a mounting bracket 33 which houses a plunger 34. Each plunger 34 is biased towards the rear of the vehicle by means of a respective spring 35, and each plunger is provided with a guide-pin 35, which engages within a guide slot 37 formed in the respective mounting bracket 33. The rear portion of each of the plungers 34 is formed with a pair of converging faces 34a and 34b which are engageable by the front edge of the associated upper retaining plate 28.

In use, if another vehicle strikes the beam 21 (that is to say the beam 21 is subjected to a force in the direction of the arrow B), the bumper assembly will pivot in a clockwise direction (as seen in the drawing) about the pivot bolts 25. As the arms 22 pivot, the hollow rubber springs 29 are compressed between their retaining plates 27 and 28, the compression of the springs resisting the pivotal movement of the arms. This pivotal movement of the arms 22 continues until the lower retaining plates 27 abut against the lower surface of the mounting channel 23.

If the beam 21 strikes an obstruction so that a force is applied thereto in the direction of the arrow A, the whole assembly will try to pivot in an anticlockwise direction about the pivot bolts 25. If the force applied in the direction of the arrow A is sufficiently large, the upper retaining plates 28 will exert a sufficiently large force on the inclined face 34a of the associated plunger 34 to force that plunger towards the front of the vehicle against the biasing force of its spring 35. This will free the upper retaining plates 28, so that the whole assembly can pivot in an anti-clockwise direction. This position is shown in dash-dot lines in the drawing. In order to reset the bumper assembly, it is necessary only to press the beam 21 in the direction of the arrow B. This causes the upper retaining plates 28 to engage the inclined faces 34b of the plunger 34, thus forcing the plungers towards the front of the vehicle, and permitting the upper retaining plates to return to their original positions.

Obviously, the bumper assembly described above with reference to Fig. 3 could be provided with a sensor for detecting displacement of the beam and activating a warning device, and such a sensor and warning device arrangement could be any of the types described above with reference to the embodiment of Figs. 1 and 2.

Although each of the bumper assemblies described above is positioned at the rear of the vehicle concerned, it will be apparent that it could equally well be positioned at the front or the sides of the vehicle.

Claims

1. A road vehicle having a bumper assembly fitted thereto, the bumper assembly comprising a beam which is supported by an arm from the vehicle so that the beam is displaceable from a rest position in a direction towards or beneath the vehicle in the event of contact with an obstacle, spring means for biasing the beam towards its rest position, and sensing means capable of detecting displacement of the beam and activating a warning device.

2. A vehicle as claimed in claim 1, wherein the sensing means comprises a proximity switch, one component of which is attached to the bumper assembly and the other to the vehicle.

3. A road vehicle as claimed in claim 2, wherein the proximity switch is a Reed switch.

4. A road vehicle as claimed in claim 2, wherein the proximity switch is constituted by a pneumatic valve and an actuating device.

5. A road vehicle as claimed in claim 4, wherein the pneumatic valve is positioned in a line leading from a pressurised air reservoir to a horn, the horn constituting the warning device.

6. A road vehicle as claimed in any one of claims 2 to 5, wherein the bumper assembly includes a rod pivotally connected to the beam or to the arm, and wherein the free end of the rod carries a component of the proximity switch.

7. A road vehicle as claimed in claim 6 when appendant to claim 5, wherein the actuating device is a bent plate carried by the free end portion of the rod.

8. A road vehicle as claimed in claim 6 or claim 7, wherein the rod is connected to a hollow rubber spring which constitutes the spring means.

9. A road vehicle as claimed in any one of claims 1 to 5, wherein the rest position is defined by a latch assembly, the latch assembly being such as to prevent the beam being displaced in a direction opposed to said direction, unless the beam is subjected to a predetermined force.

10. A road vehicle as claimed in claim 9, wherein the spring means is a hollow rubber spring which is mounted on a rod and positioned between a pair of retaining plates.

11. A road vehicle as claimed in claim 10, wherein one of the retaining plates is fixed to the arm, the other retaining plate being pivotally connected to the arm by means of a pivot bolt which also constitutes the pivotal connection between the arm and the Vehicle.

12. A road vehicle as claimed in claim 11, wherein the latch assembly is constituted by a spring-biased plunger mounted on the vehicle and by said other retaining plate.

13. A vehicle as claimed in any one of claims 1 to 12, wherein the beam is supported by a pair of arms, a respective spring means being associated with each of the arms.

14. A vehicle as claimed in claim 13, wherein a respective sensing means is associated with each of the arms.

15. A road vehicle as claimed ineany one of claims 1 to 14, wherein the warning device is in proximity to the driving position.

1 6. A road vehicle having a bumper assembly fitted thereto, the bumper assembly comprising a beam which is pivotally supported by an arm from the vehicle so that the beam is displaceable from a rest position in a first direction towards or beneath the vehicle in the event of contact with an obstacle, and spring means for biasing the beam towards its rest position, wherein the rest position is defined by a latch assembly, the latch assembly being such as to prevent the beam being displaced in a direction opposed to said first direction, unless the beam is subjected to a predetermined force.

17. A road vehicle as claimed in claim 16, wherein the spring means is constituted by a hollow rubber spring.

1 8. A road vehicle as claimed in claim 17, wherein the hollow rubber spring is mounted on a rod and positioned between a pair of retaining plates.

19. A road vehicle as claimed in claim 18, wherein one of the retaining plates is fixed to the arm, the other retaining plate being pivotally connected to the arm by means of a pivot bolt which also constitutes the pivotal connection between the arm and the vehicle.

20. A road vehicle as claimed in claim 19, wherein the latch assembly is constituted by a spring-biased plunger mounted on the vehicle and by said other retaining plate.

21. A road vehicle bumper assembly substantially as hereinbefore described with reference to, and as illustrated by, the Figs. 1 and 2 or Fig. 3 of the accompanying drawings.