GB2379194A

GB2379194A - Emergency responsive vehicle bumper

Info

Publication number: GB2379194A
Application number: GB0219814A
Authority: GB
Inventors: Takis Sozou
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-08-28
Filing date: 2002-08-23
Publication date: 2003-03-05
Anticipated expiration: 2022-08-23
Also published as: GB0120834D0; GB0219814D0; GB2379194B

Abstract

A vehicle bumper includes a mounting arrangement which comprises at least one extensible element which is operable to move the bumper or fender from a first position to a second position (figures 1 and 2) in response to a signal from a sensor. In its second position the bumper is capable of absorbing impact energy as it is forced back during an impact. The extensible element 4 may comprise a piston 38 and cylinder 10 whereby the piston moves along the cylinder due to the sensor 8 triggering a pyrotechnic means or a source of compressed gas 52. The cylinder may have two gas inlet valves 22, 32 and two gas outlet valves 24, 30 so that the piston may be moved between the first and second positions in both directions under the action of the gas source. The cylinder may also include an energy absorbing spring (70, figure 6). The sensor may be triggered due to the speed of the vehicle, the speed of the vehicle relative to an object, and the distance between the vehicle and said object.

Description

DESCRIPTION OF INVENTION "A SAFETY APPARATUS FOR A MOTOR VEHICLE" THE PRESENT INVENTION relates to a safety apparatus for a motor vehicle.

Bumpers or fenders fitted to motor vehicles are well known, and are commonly fitted to private, public, commercial and industrial motor vehicles which are driven on the public highways, off road etc. Current bumper designs do not, however, generally offer a lot of protection in the event of a crash, particularly in the case of light weight bumpers fitted to large vehicles, eg of the saloon type, which can result in expensive damage to the vehicle even when the crash occurs at low to moderate speed.

The present invention seeks to provide a safety apparatus which enhances the effectiveness of current bumper designs.

According to the present invention, there is provided a safety apparatus for use on a motor vehicle, the apparatus comprising a bumper or fender and a mounting arrangement for mounting the bumper or fender to the motor vehicle, wherein the mounting arrangement comprises at least one extensible element which is operable to move the bumper or fender from a first position to a second position in response to a signal from a sensor.

Preferably, the or each extensible element is capable of resisting movement of the bumper from the second position to the first position with an energy absorbing affect.

Conveniently, the or each extensible element comprises a piston and cylinder unit.

Advantageously, the piston and cylinder unit is connected to a source of gas to extend the extensible element.

Preferably, said source of gas is a container of pressurised gas.

Alternatively, said source of gas may comprise a pyrotechnic device.

Advantageously, the cylinder has two electrically controlled gas inlet valves, each gas inlet valve being situated at a respective end of the cylinder on either side of the piston and connected to the source of gas, and two electrically controlled gas outlet valves, each gas outlet valve being situated at a respective end of the cylinder on either side of the piston, the signal from the sensor opening the gas inlet valve at one end and the gas outlet valve at the other end to cause the piston and cylinder unit to extend.

Preferably the safety apparatus is further provided with a position sensor responsive to the position of the bumper or fender to open the gas outlet valve at said one end and the gas inlet valve at the other end to return the piston and cylinder unit to an unextended state.

Conveniently, the position sensor is a micro-switch.

Preferably, the piston and cylinder unit further includes a deformable energy-absorbing member within the cylinder and a mechanism to prevent movement of part of the deformable energy-absorbing member in one pre- determined direction, with the deformable energy-absorbing member being located between the piston and the mechanism.

Preferably, the mechanism is controlled catches on the cylinder to catch an auxiliary element within the cylinder, the deformable member being between the piston and the auxiliary element.

Conveniently, the deformable member is a spring.

Advantageously, said sensor measures at least one parameter selected from the group comprising the absolute speed of the vehicle, the relative speed of the vehicle and an object and the relative distance between the vehicle and an object, further wherein the output from the sensor generates a pre-determined signal in response to the measured parameter or parameters exceeding a pre-determined threshold.

Advantageously, the sensor is a radar sensor.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a partial perspective view of a motor vehicle equipped with a safety apparatus in accordance with the present invention, in an initial condition; FIGURE 2 is a view corresponding to Figure 1 with the safety apparatus in a subsequent condition ; FIGURE 3 is a part sectional and part elevational view of the individual components of a piston and cylinder unit; FIGURE 4 is a part sectional and part elevational view of an assembled piston and cylinder unit in an initial condition and an associated source of pressurised gas; FIGURE 5 is a view corresponding to Figure 4 but with the piston and cylinder unit in a subsequent condition.

FIGURE 6 is a part sectional and part elevational view of an alternate piston and cylinder unit in an initial condition; and FIGURE 7 is a view corresponding to Figure 6 but with the alternate piston and cylinder unit in a subsequent condition.

Figures 1 and 2 show a motor vehicle provided with a safety apparatus in accordance with the present invention. The vehicle is provided with a front bumper 2 mounted to the vehicle by two mounting units 4,6 (visible in Figure 2) which are each extensible. The vehicle further incorporates a sensor 8, such as a radar sensor, located at the front of the vehicle to sense objects in front of the vehicle and to determine the distance between the vehicle

and the object, and the relative speed of the vehicle with reference to the object.

The sensor generates an output signal in response to predetermined conditions, for example a high relative speed and a short distance. The signal causes the extensible mounting units 4,6 to be activated to extend to move the bumper 2 from a first or initial position as shown in Figure 1 to a second or forward position as shown in Figure 2.

In a subsequent collision between the motor vehicle and the object in front of the motor vehicle, at least some energy of the collision may be absorbed by the bumper as it is moved back towards the vehicle.

Referring to Figure 3, a mounting unit 4 in the form of a piston and cylinder unit comprises a cylinder 10, having a screw-on end cap 12, a piston 14 and a connector 16.

The cylinder 10 is of tubular form and has an aperture 18 defined at one end by radially-inwardly protruding annular seal 20. Immediately adjacent the seal, a solenoid-controlled gas inlet valve 22 and a solenoid-controlled gas outlet valve 24 are provided on opposed sides of the cylinder 10. A microswitch 26 is mounted at the said end of the cylinder 10.

The other end of the cylinder 10 is provided with external screwthreading 28 and, adjacent the threading, a solenoid-controlled gas outlet valve 30 is provided. A high-pressure gas release valve 31 is positioned on the opposite side of the cylinder 10.

The end cap 12, which is to be screwed on to the threading 28, is provided with a solenoid-controlled gas inlet valve 32 which is mounted on its

end wall. The end cap 12 contains a conical tapering spring 34, which tapers towards a point remote from the end cap.

The piston 14 has a head 36 formed at one end of a shaft 38, the other end of which is threaded 40. A helical spring 42 is wound around the piston shaft 38, and abuts the head 36. A tight fitting washer 44 is mounted to the piston shaft 38 adjacent the threading 40.

The connector 16 comprises a flat plate 46 from which a short length of hollow tubing 48 extends. The hollow tube 48 carries internal threading 50 which is dimensioned to mate with the threading 40 formed at said other end of the piston shaft 38.

Referring to Figure 4, the piston and cylinder unit is shown assembled in an initial condition with both of the solenoid-controlled gas inlet valves 22,32 shown connected to a pressurised air container 52 by tubing 54,56. The piston and cylinder unit is thus connected to a source of gas. Both solenoid-controlled gas outlet valves 24,30 lead, when opened, to the atmosphere.

The piston head 36 is located within the cylinder 10 as a gas-tight sliding fit, and the piston shaft 38 passes through the annular seal 20 as a gas-tight sliding fit. The washer 44 is on the exterior of the cylinder 10, between the seal 20 and the connector 16 which is connected to the threaded end 40 of the piston shaft 38.

In an initial condition, the piston head 36 is located adjacent to the end cap 12, and abuts the helical tapering spring 34. The tapering nature of helical tapering spring 34 means that it does not interfere with the gas-tight seal formed between the piston head 36 and the cylinder 10.

When the piston and cylinder unit is in the first condition, the washer 44 contacts the micro-switch 26, thus placing the micro-switch into an"off position.

In use, the cylinder 10 is clamped by a clamp (not shown) to the body of the vehicle and the plate 46 of the connector 16 is secured to the rear part of a bumper.

Each of the solenoid-controlled gas inlet valves 32,22 is in electrical connection with the sensor 8. Likewise, each of the solenoid-controlled gas outlet valves 24,30 is in electrical connection with the sensor 8. The

micro-switch 26 is connected through a timer unit 58 to the sensor 8.

In response to pre-determined conditions, the sensor generates an output signal which opens the gas inlet valve 32 at one end of the cylinder and the gas outlet valve 24 at the other end of the cylinder (the other gas inlet valve 22 and the other gas outlet valve 30 remain closed). Pressurised air from the container 52 flows through the tubing 54 and through the gas-inlet valve 32 into the gas-tight chamber behind the piston head 36, and acts to push the piston 14 in the direction shown by the arrow marked"A". The air trapped in front of the piston head 36 is permitted to escape to the atmosphere through the gas-outlet valve 24.

It is to be appreciated that the piston 14 will continue to move in this direction until it adopts the subsequent condition as shown in Figure 5, thus extending the piston and cylinder unit (and hence the bumper moves to a position in which it is positioned in front of the vehicle body as shown in Figure 2).

The piston 14 is prevented from moving further in the direction shown by the arrow"A"as the diameter of piston head 36 is too great to fit through the aperture 18 of the cylinder 10. The helical spring 42 is compressed between the piston head 36 and the annular seal 20. The helical spring 42 therefore provides some cushioning between the piston head and the annular seal 20 of the cylinder 10.

If an object strikes the bumper, tending to move the bumper 2 towards the vehicle body, the piston and cylinder unit will resist the movement of the bumper 2 as some of the energy of the collision will be absorbed through the compression of the air behind the piston head 36. If the pressure of the air behind the piston head 36 increases beyond a pre-determined value, the high pressure gas release valve 31 opens to release some of the air with a throttling effect so that as the piston moves energy is absorbed. It is to be appreciated that the piston and cylinder mounting unit 4 therefore provides an energy absorbing effect.

When the piston 14 is extended, as shown in Figure 5, the washer 44 no longer contacts the micro-switch 26, and so the micro-switch adopts an"on" position, and sends a "return" signal to the sensor arrangement 8 after a delay provided by the timing unit 58. The micro-switch is thus a sensor responsive to the position of the piston.

The signal from the timing unit 58 causes the sensor 8 to close the gas inlet valve 32 and the gas outlet valve 24, and open the gas inlet valve 22 and the gas outlet valve 30. Pressurised air from the container 52 will flow through the tube 56 and push the piston head 36 in the direction opposite to the arrow marked"A". Air trapped behind the piston head 36 will now be able to escape

through the gas-outlet valve 30, and thus the piston 14 will move back to the initial condition as shown in Figure 4.

Once the piston and cylinder unit has returned to the initial condition, the washer 44 will contact the micro-switch 26, therefore switching the micro-switch to the off position. The safety arrangement is thus ready for reuse.

With reference to Figures 6 and 7, an alternative embodiment of the piston and cylinder mounting unit will now be described. The alternative embodiment incorporates many of the same features described in the previous embodiment, and these features will not be re-described here.

The cylinder 10 is provided with a pair of opposed solenoid-operated catches 60,62 located in the region of the mid point of the cylinder. These catches are initially retracted from the interior of the cylinder 10 but may project into the cylinder 10 in response to a signal.

An auxiliary piston 64, which has a piston shaft 66 and a piston head 68, is located in the cylinder in between the piston 14 and the end cap 12. The piston head 68 is dimensioned to fit within the cylinder 10 without forming a gas-tight seal. A helical spring 70 is located between the shaft 66 of the auxiliary piston 64 and the head of the piston 14.

The solenoid-controlled catches 60,62 are connected to the sensor 8, and in the initial condition shown in Figure 6 are withdrawn. The piston and cylinder unit illustrated in Figure 6 and Figure 7 is mounted to the motor vehicle body and bumper in the manner as previously described.

In response to pre-determined conditions, the sensor generates an output signal which opens the gas inlet valve 32 at one end of the cylinder and the gas outlet valve 24 at the other end of the cylinder (gas inlet valve 22 and gas outlet valve 30 remain closed). Pressurised air flows into the cylinder 10 through the gas inlet valve 32. The air is injected into the cylinder between the head 68 of the auxiliary piston 64 and acts on that piston. Some of the air flows past the non-sealing piston head 68 of the auxiliary piston 64 and acts on the head 36 of the piston 14. Consequently, the auxiliary piston 64 and the piston 14 both move forwardly, that is, in the direction shown by the arrow marked"A". The open gas outlet valve 24 allows air trapped in front of the piston head 36 of the main piston 14 to escape.

The helical spring 42 becomes compressed between the piston head 36 and the annular seal 20. Once the piston head 68 of the auxiliary piston 64 has moved past the catches 60,62, the catches 60,62 move to project into the cylinder at a position behind the piston head 68 of the auxiliary piston 64. Thus the auxiliary piston 64 may not move to the left.

It is to be appreciated that any rearward movement of the bumper (i. e. in a direction opposite to the arrow marked"A") caused by an impact will be resisted by the combination of two factors; firstly, compression of the pressurised air trapped behind the piston head 36 of the piston 14, and secondly, compression of the helical spring 70 located between the piston 14 and the auxiliary piston 64.

To return the piston and cylinder unit to its original condition as shown in Figure 6, the gas inlet valve 32 and the gas outlet valve 24 are both closed, whilst the gas inlet valve 22 on the other side of the piston and the gas outlet

valve 31 are both opened. In addition, the catches 60,62 are retracted from their projecting position shown in Figure 7 to their non-projecting position as shown in Figure 6. Pressurised air will flow through the gas inlet valve 22 into the gas-tight chamber formed between the annular seal 20 and the front of the piston head 36, pushing the piston in a rearward direction, that is, in a direction opposite to the arrow marked"A"as shown in Figure 6. The air trapped behind the piston head 36 is free to escape through the gas outlet valve 30. The piston 14 and the auxiliary piston 64 will both be moved rearwardly until they adopt the initial condition as shown in Figure 6 at which point the micro-switch 26 is closed, which causes all valves to be closed.

The catches 60,62 as described previously may be designed to break or snap once a certain pre-determined very high force has been applied to them by the piston head 68 of the auxiliary piston 64.

In the described embodiments the sensor senses relative distance and relative speed between the vehicle and an object, but it could additionally measure the absolute speed of the vehicle so that, for example, the system could be automatically overridden whilst the vehicle is moving in slow traffic.

Whilst the sensor 8 described is a radar sensor, any other type of sensor which fulfils the required purpose could be used, for example, an ultrasonic or infrared sensor.

It is proposed that a manual override switch could be provided, either to actuate the piston and cylinder unit to space the bumper from the motor vehicle if the driver feels this to be desirable (as shown in Figure 2), or to ensure that the piston and cylinder unit will not be actuated, even in the event that the

sensor establishes that a measured parameter has exceeded a certain pre-determined threshold.

Although the described piston and cylinder units are connected to the bumper via a connector 16, the piston 14 could be directly connected to the bumper. The bumper may be provided with a sub-frame of metal or high performance plastic which acts to strengthen the bumper. The sub-frame may be directly or resiliently connected to the bumper with the piston and cylinder units being connected to the sub-frame.

It is to be noted that whilst the invention has been described with reference to the front-bumper of a motor vehicle, an equivalent system could be applied equally well to the rear-bumper of a motor vehicle.

It is intended that the safety device of the invention will not impair the safety crumple zone of the motor vehicle to which it is fitted.

Whilst the preferred and alternate embodiments have been described as being actuated by a container of pressurised air, another source of pressurised gas could be used, such as a pyrotechnic device, acting either in isolation or in tandem with a container of pressurised air.

In the present Specification"comprises"means"includes or consists of and"comprising"means"including or consisting of.

The features disclosed in the foregoing description, or the following Claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any

combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS 1. A safety apparatus for use on a motor vehicle, the apparatus comprising a bumper or fender and a mounting arrangement for mounting the bumper or fender to the motor vehicle, wherein the mounting arrangement comprises at least one extensible element which is operable to move the bumper or fender from a first position to a second position in response to a signal from a sensor.
2. A safety apparatus according to Claim 1 wherein the or each extensible element is capable of resisting movement of the bumper from the second position to the first position with an energy absorbing affect.
3. A safety apparatus according to Claim 1 or Claim 2, wherein the or each extensible element comprises a piston and cylinder unit.
4. A safety apparatus according to Claim 3 wherein the piston and cylinder unit is connected to a source of gas to extend the extensible element.
5. A safety apparatus according to Claim 4 wherein said source of gas is a container of pressurised gas.
6. A safety apparatus according to Claim 4 wherein said source of gas comprises a pyrotechnic device.
7. A safety apparatus according to Claim 5 wherein the cylinder has two electrically controlled gas inlet valves, each gas inlet valve being situated at a respective end of the cylinder on either side of the piston and connected to the source of gas, and two electrically controlled gas outlet valves, each gas outlet valve being situated at a respective end of the cylinder on either side of the

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piston, the signal from the sensor opening the gas inlet valve at one end and the gas outlet valve at the other end to cause the piston and cylinder unit to extend.
8. A safety apparatus according to Claim 7 further provided with a position sensor responsive to the position of the bumper or fender to open the gas outlet valve at said one end and the gas inlet valve at the other end to return the piston and cylinder unit to an unextended state.
9. A safety apparatus according to Claim 8, wherein the position sensor is a micro-switch.
10. A safety apparatus according to any one of Claims 3 to 9, wherein the piston and cylinder unit further includes a deformable energy-absorbing member within the cylinder and a mechanism to prevent movement of part of the deformable energy-absorbing member in one pre-determined direction, with the deformable energy-absorbing member being located between the piston and the mechanism.
11. A safety apparatus according to Claim 10, wherein the mechanism is controlled catches on the cylinder to catch an auxiliary element within the cylinder, the deformable member being between the piston and the auxiliary element.
12. A safety apparatus according to Claim 10 or Claim 11, wherein the deformable member is a spring.
13. A safety apparatus according to any one of the preceding Claims, wherein said sensor measures at least one parameter selected from the group comprising the absolute speed of the vehicle, the relative speed of the vehicle

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and an object and the relative distance between the vehicle and an object, further wherein the output from the sensor generates a pre-determined signal in response to the measured parameter or parameters exceeding a pre-determined threshold.
14. A safety apparatus according to Claim 13, wherein the sensor is a radar sensor.
15. A safety apparatus substantially as herein described with reference to and as shown in Figures 1 to 5 of the accompanying drawings.
16. A safety apparatus substantially as herein described with reference to and as shown in Figures 1 to 5 as modified by Figures 6 and 7 of the accompanying drawings.
17. Any novel feature or combination of features disclosed herein.