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Title:
EMERGENCY ACTIVATED BRAKE SYSTEM
Document Type and Number:
WIPO Patent Application WO/2015/160265
Kind Code:
A1
Abstract:
An emergency activated brake system for a vehicle, comprising a structural frame, a hinged mass movably supported by at least one link assembly, a control-lever, a braking activation device configured, in use, to activate brakes on the vehicle, a biasing element connected to the hinged mass; wherein the hinged mass and control-lever have: a non-braking configuration, in which the hinged mass prevents the control-lever from contacting said braking activation device; and a braking configuration, in which the hinged mass allows the control-lever to contact the braking activation device, wherein the biasing element biases the hinged mass towards the non-braking configuration; wherein in use, if forward acceleration of the structural frame exceeds a predetermined amount for a predetermined time, the hinged mass and control-lever move from the non-braking configuration to the braking configuration.

Inventors:
MUNRO NEIL (NZ)
Application Number:
NZ2015/000027
Publication Date:
October 22, 2015
Filing Date:
April 14, 2015
Export Citation:
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Assignee:
TRANSP WHOLESALE LTD (NZ)
International Classes:
B60T13/06; B60T7/04; B60T7/08; B60T7/22; B60T13/00
Foreign References:
US3752250A1973-08-14
US4255629A1981-03-10
GB2453523B2011-11-09
US4768391A1988-09-06
Attorney, Agent or Firm:
LUCAS, Jonathan, D,M. et al. (Level 12 KPMG Centre,85 Alexandra Street,Private Bag 3140, Waikato Mail Centre Hamilton 3240, NZ)
Download PDF:
Claims:
An emergency activated brake system for a vehicle, comprising:

a structural frame for mounting on a vehicle;

a hinged mass movably supported on the structural frame by at least one link assembly; a control-lever moveably connected to the structural frame;

a braking activation device mounted on the structural frame and configured, in use, to activate brakes on the vehicle upon receiving contact from the control-lever;

a biasing element connected to the hinged mass;

wherein the hinged mass and control-lever have:

a non-braking configuration, in which the hinged mass prevents the control- lever, which is biased towards the braking activation device, from contacting said braking activation device; and

a braking configuration, in which the hinged mass allows the control-lever to contact the braking activation device, and the control-lever is in contact with the braking activation device;

wherein the biasing element biases the hinged mass towards the non-braking configuration;

wherein in use, if forward acceleration of the structural frame exceeds a predetermined amount for a predetermined time, the hinged mass overcomes the biasing force and moves rearward through a predetermined distance, and the hinged mass and control-lever move from the non-braking configuration to the braking configuration.

The emergency activated brake system of claim 1, wherein the hinged mass comprises a body to which the link assembly or assemblies are pivotally attached.

The emergency activated brake system of claim 1, wherein the hinged mass comprises a plate, the link assembly integrally formed with the plate.

The emergency activated brake system of any one of the preceding claims, wherein the hinged mass comprises a contact surface on which the control-lever is supported in the non-braking configuration, the contact surface being configured so that during initial rearward movement of the hinged mass, the control-lever does not move substantially.

5. The emergency activated brake system of any one of the preceding claims, wherein the control- lever comprises a low friction component configured to provide low friction movement of the control-lever on the hinged mass.

6. The emergency activated brake system of claim 5, wherein the low friction component is a roller mounted to the control-lever.

7. The emergency activated brake system of claim 5, wherein the low friction component is a pad formed from a low friction material.

8. The emergency activated brake system of any one of the preceding claims, wherein the biasing element is an extension spring connected to the hinged mass to bias the hinged mass forward towards the non-braking configuration. 9. The emergency activated brake system of claim 8, wherein the extension spring is connected at a first end to the hinged mass, and at a second end to the control-lever, to bias the hinged mass forward towards the non-braking configuration while biasing the control lever towards contact with the braking activation device. 10. The emergency activated brake system of claim 8 or claim 9, wherein the braking activation device requires contact with a sufficient force before activating the brakes, and if the extension spring fails, the control-lever does not contact the braking activation device with the sufficient force.. 11. The emergency activated brake system of any one of claims 8-10, wherein the extension spring is connected to the link assembly of the hinged mass.

12. The emergency activated brake system of any one of the preceding claims, wherein after the hinged mass and control-lever have moved from the non-braking configuration to the braking configuration, they are locked in the braking configuration.

13. The emergency activated brake system of claim 12, wherein after the hinged mass and control- lever are locked in the braking configuration, they are able to be manually moved from the braking configuration to the non-braking configuration.

14. The emergency activated brake system of claim 12 or claim 13, wherein the hinged mass and control-lever are able to be moved from the braking configuration to the non-braking configuration by rotating the control-lever with a tool.

15. The emergency activated brake system of any one of the preceding claims, wherein the system comprises an enclosure.

16. The emergency activated brake system of any one of the preceding claims, wherein the

emergency activated brake system is configured to be removable from the vehicle.

17. The emergency activated brake system of any one of the preceding claims, wherein the brakes are air brakes, and the braking activation device is a pneumatic valve configured to, when contacted, be depressed and activate the air brakes.

18. The emergency activated brake system of claim 17, wherein the pneumatic valve is configured to, when depressed, open a pneumatic circuit allowing air to flow from an air brake system reservoir to shuttle valves installed between a foot brake valve and the service brakes on the vehicle, to activate the service brakes.

19. The emergency activated brake system of claim 18, wherein the emergency activated brake system comprises a normally open 3/2 way solenoid valve between the pneumatic valve and the shuttle valves, the normally open solenoid valve configured to, when energised, close the pneumatic circuit to prevent air from flowing from the air brake system reservoir to the shuttle valves, and allow the shuttle valves to exhaust air to atmosphere.

20. The emergency activated brake system of claim 17, wherein the pneumatic valve is configured to, when depressed, apply parking brakes on the vehicle.

21. A vehicle, comprising an emergency activated brake system of any one of claims 1-20.

22. A method of activating an emergency braking system, comprising the steps of:

imparting a biasing force on a mass associated with a control-lever such that the biasing force directs the mass and associated control-lever towards an inactivated position in which the vehicle's brakes are not activated; moving the mass and associated control-lever against the biasing force, upon an impact occurring, when the force of the impact is sufficient to overcome the biasing force, to cause the mass and control-lever arm to move towards an activated position which activates the emergency braking system.

23. A testing apparatus for testing an emergency activated brake system as claimed in any one of claims 1-20, comprising:

a lever to which the emergency activated brake system can be attached;

a weight connected to the lever;

a release mechanism configured to release the weight, causing a corresponding acceleration of the emergency activated brake system;

wherein acceleration of the emergency activated brake system is a predetermined acceleration through a predetermined distance based on the positioning of the emergency activated brake system and the weight on the lever, and the masses of the emergency activated brake system and the weight, and a distance that the weight is free to fall.

24. An emergency activated brake system substantially as hereinbefore described with reference to any one of the embodiments shown in the Figures.

25. A vehicle substantially as hereinbefore described with reference to any one of the embodiments shown in the Figures.

26. A method of activating an emergency braking system substantially as hereinbefore described with reference to any one of the embodiments shown in the Figures.

27. A testing apparatus substantially as hereinbefore described with reference to the embodiment shown in Figure 6.

Description:
EMERGENCY ACTIVATED BRAKE SYSTEM

Field of Invention The invention relates to an emergency brake activation system. More particularly, the invention relates to a system for automatically applying brakes on a vehicle in the event of a severe impact. Even more particularly, the invention relates to a system for applying air brakes on a first vehicle upon an impact to the rear of the first vehicle from a second vehicle. Background of Invention

Personnel working on a road will often work in front of a vehicle parked on the road or moving slowly behind the workers. Typically the vehicle is a truck. The truck can provide signage to redirect oncoming vehicles using the road, and also provides a physical barrier between the traffic approaching the truck from the rear, and the personnel working in front of the truck.

Many trucks used for this purpose are equipped with an attenuator used to absorb the impact of a vehicle that fails to stop or avoid the truck. Typically, attenuators are configured to fail in a controlled manner over a distance (e.g. in the manner of a crash cushion), to absorb kinetic energy of the impacting vehicle while reducing the force between the two vehicles and reducing the magnitude of deceleration of the oncoming vehicle.

Many such vehicles used for the purpose of protecting personnel working in front of the vehicle are equipped with air brakes. Trucks equipped with air brakes generally have a parking brake system which incorporates springs configured to apply the brakes, and air chambers configured to compress the springs to release the park brakes. Failure of the pneumatic brake system resulting in low air pressure therefore results in application of the parking brakes, given the springs are no longer able to be compressed. Generally park brakes are only installed on rear axles of trucks with pneumatic brakes. The service brakes, however, are installed on both front and rear axles.

While the truck may be parked with its parking brake engaged, it is advantageous for the truck's service brakes to be engaged after an impact, to enable braking of both front and rear axles, along with the use of ABS. Furthermore, if the truck is slowly moving behind workers, the park brakes are not engaged, so it is necessary for brakes to be engaged after an impact to the rear of the truck. In a serious impact, the driver of the truck may be incapacitated or not be able to apply the service brakes quickly enough to stop the truck moving forward to the workers in front.

One means of enabling the use of the truck's service brakes to minimise or prevent movement of the protective vehicle is an Automatic Impact Braking (AIB) system installed on the truck. One class of existing AIB systems involves electronic components mounted externally on the rear of an attenuator mounted on the truck, which detects contact between an oncoming vehicle and the attenuator. Upon contact, the electronic detector (e.g. a tape switch) activates a solenoid valve to initiate application of the vehicle's brakes.

One disadvantage of this existing AIB system is that it can be activated too easily, which is a hazard when the system is not intended to be activated, such as when the truck is driving. The risk is caused at least in part by the relatively small force required to activate the pressure sensitive detector, and exacerbated by the electronic design of the system, which can malfunction due to various faults, such as short circuits.

Some existing AIB systems apply only the parking brakes of the truck. However, as the parking brakes are often installed on rear axles of a truck only, it would be advantageous for an improved AIB solution to be configured to apply the service brakes on front and rear axles to maximise the braking effect. As modern trucks have ABS systems which operate on the service brakes, it is advantageous to apply the service brakes rather than the parking brakes, to improve the directional control available to the driver.

It is an object of the invention to provide an emergency activated brake system that addresses at least one of the disadvantages of the prior art. Alternatively, it is an object of the invention to at least provide the public with a useful choice.

Summary of Invention

According to a first aspect of the invention there is provided an emergency activated brake system for a vehicle, comprising:

a structural frame for mounting on a vehicle;

a hinged mass movably supported on the structural frame by at least one link assembly;

a control-lever moveably connected to the structural frame;

a braking activation device mounted on the structural frame and configured, in use, to activate brakes on the vehicle upon receiving contact from the control-lever; a biasing element connected to the hinged mass;

wherein the hinged mass and control-lever have:

a non-braking configuration, in which the hinged mass prevents the control-lever, which is biased towards the braking activation device, from contacting said braking activation device; and

a braking configuration, in which the hinged mass allows the control-lever to contact the braking activation device, and the control-lever is in contact with the braking activation device; wherein the biasing element biases the hinged mass towards the non-braking configuration; wherein in use, if forward acceleration of the structural frame exceeds a predetermined amount for a predetermined time, the hinged mass overcomes the biasing force and moves rearward through a predetermined distance, and the hinged mass and control-lever move from the non-braking configuration to the braking configuration.

The hinged mass may have a variety of different forms.

In one embodiment the hinged mass may have a body to which a link assembly or assemblies are pivotally attached.

Preferably, the hinged mass may be in plate form, the link assembly integrally formed with the plate.

Preferably, the hinged mass comprises a contact surface on which the control-lever is supported in the non-braking configuration, the contact surface being configured so that during initial rearward movement of the hinged mass, the control-lever does not move substantially. Preferably, the control-lever comprises a low friction component configured to provide low friction movement of the control-lever on the hinged mass. Preferably, the low friction component is a roller mounted to the control lever. Alternatively, the low friction component is a pad formed from a low friction material. Preferably, the biasing element is an extension spring connected to the hinged mass to bias the hinged mass forward towards the non-braking configuration.

Preferably, the extension spring is connected at a first end to the hinged mass, and at a second end to the control-lever, to bias the hinged mass forward towards the non-braking configuration while biasing the control lever towards contact with the braking activation device. Preferably, the braking activation device requires contact with a sufficient force before activating the brakes, and if the extension spring fails, the control-lever does not contact the braking activation device with the sufficient force.

More preferably, the extension spring is connected to the link assembly of the hinged mass.

Preferably, after the hinged mass and control-lever have moved from the non-braking configuration to the braking configuration, they are locked in the braking configuration.

Preferably, after the hinged mass and control-lever are locked in the braking configuration, they are able to be manually moved from the braking configuration to the non-braking configuration. More preferably, the hinged mass and control-lever are able to be moved from the braking configuration to the non-braking configuration by rotating the control-lever with a tool.

Preferably, the emergency activated brake system comprises an enclosure.

Preferably, the emergency activated brake system is configured to be removable from the vehicle.

Preferably, the brakes are air brakes, and the braking activation device is a pneumatic valve configured to, when contacted with sufficient force, be depressed and activate the air brakes.

Preferably, the pneumatic valve is configured to, when depressed, open a pneumatic circuit allowing air to flow from an air brake system reservoir to shuttle valves installed between a foot brake valve and service brake systems (front axle and rear axle systems) on the vehicle, to activate the service brakes.

Preferably, the emergency activated brake system comprises a normally open 3/2 way solenoid valve between the pneumatic valve and the shuttle valves, the normally open solenoid valve configured to, when energised, close the pneumatic circuit to prevent air from flowing from the air brake system reservoir to the shuttle valves, and allow the shuttle valves to exhaust air to atmosphere.

In another embodiment, the pneumatic valve is configured to, when depressed, apply parking brakes on the vehicle. According to another aspect of the invention there is provided a vehicle comprising an emergency activated brake system substantially as described above.

According to another aspect of the invention there is provided a method of activating an emergency braking system, comprising the steps of:

imparting a biasing force on a mass associated with a control-lever such that the biasing force directs the mass and associated control-lever towards an inactivated position in which the vehicle's brakes are not activated;

moving the mass and associated control-lever against the biasing force, upon an impact occurring, when the force of the impact is sufficient to overcome the biasing force, to cause the mass and control-lever arm to move towards an activated position which activates the emergency braking system.

According to another aspect of the invention there is provided a testing apparatus for testing an emergency activated brake system according to the first aspect of the invention, comprising:

a lever to which the emergency activated brake system can be attached;

a weight connected to the lever;

a release mechanism configured to release the weight, causing a corresponding acceleration of the emergency activated brake system;

wherein acceleration of the emergency activated brake system is a predetermined acceleration through a predetermined distance, based on the positioning of the emergency activated brake system and the weight on the lever, and the masses of the emergency activated brake system and the weight, and a distance that the weight is free to fall. Further aspects of the invention, which should be considered in all its novel aspects, will become apparent to those skilled in the art upon reading of the following description which provides at least one example of a practical application of the invention.

Brief Description of the Drawings

One or more embodiments of the invention will be described below by way of example only, and without intending to be limiting, with reference to the following drawings, in which:

Figure 1 is a side view illustration of a truck having an emergency activated brake system

according to an embodiment of the invention; Figure 2 is a side view illustration of an emergency activated brake system according to one embodiment of the invention in a non-braking configuration; Figure 3a is a side view illustration of the emergency activated brake system of Figure 2 in another configuration;

Figure 3b is a cross section plan view illustration of section A-A of the emergency activated brake system of Figure 2 in the configuration shown in Figure 3a;

Figure 4 is a side view illustration of the emergency activated brake system of Figure 2 in a

braking configuration;

Figure 5 is a schematic illustration of a pneumatic circuit according to an embodiment of the invention;

Figure 6 is a side view illustration of a testing machine according to an embodiment of the

invention; Figure 7 is a side view illustration of an emergency activated brake system according to another embodiment of the invention in a non-braking configuration;

Figure 8 is a side view illustration of the emergency activated brake system of Figure 7 in another configuration;

Figure 9 is a side view illustration of the emergency activated brake system of Figure 8 in a

braking configuration; and

Figure 10 is a schematic illustration of a pneumatic circuit according to an alternative embodiment of the invention.

Detailed Description of Preferred Embodiments of the Invention

Preferred embodiments of the invention relate to the emergency application of air-operated brakes on a vehicle in response to the impact of a following second vehicle that is travelling at a higher speed and collides with the rear end of the first vehicle, or a crash cushion mounted on the rear of the first vehicle, If the second vehicle is heavier than the first vehicle and/or is travelling significantly faster, the impact may temporarily incapacitate the driver of the first vehicle and prevent or delay the application of the brakes on the first vehicle. Alternatively, if the first vehicle is parked, there may be no driver present to apply the service brakes of the vehicle. An emergency activated brake system installed on the first vehicle mitigates the risk of injury to persons in the path of the first vehicle, and occupants of the first vehicle, by reducing the distance the vehicle travels after an impact from the second vehicle.

Embodiments of the invention provide for an emergency activated brake system that responds to the acceleration of the first vehicle during a collision and applies brakes of the first vehicle when the acceleration has been maintained above a threshold level for a pre-determined time interval.

The rate of acceleration of a first vehicle, having an attenuator (such as a crash-cushion like device) mounted thereon, during a collision, is proportional to the force required to deform the attenuator and is inversely proportional to the mass of the first vehicle. The force required to shorten the attenuator can vary as it becomes shorter but if it is constant, the rate of acceleration of the first vehicle during a collision remains constant and does not depend on the mass or speed of the second vehicle. The duration of the collision impulse does depend on the mass and speed of the second vehicle and is a good indication of the severity of the collision.

Figure 1 shows a side elevation view illustration of a truck 1 with a rear mounted attenuator crash cushion 2 in a horizontal position. Many such attenuators can be moved between a horizontal position and a vertical position. The vertical position of crash cushion 2 is shown in phantom in Figure 1. When a second vehicle collides with the rear of the crash cushion, the force required to deform the crash cushion 2 will accelerate the truck 1 forwards and the reaction to that force will decelerate the second vehicle.

It will be appreciated that the invention is not limited to use on vehicles with crash cushions or other attenuators.

An AIB module in the form of a control box 3 containing components that enable the application of the brakes of the truck 1 is mounted on the truck 1. The control box 3 may be fixed securely to any convenient location on the vehicle. Truck 1 is equipped with air brakes. The control box 3 is connected to the brake system via the pneumatic circuit shown in Figure 5, described in further detail below.

Figure 2 shows a representation of the internal components of control box 3, while the internal components are in a non-braking configuration. The control-box comprises a structural frame 4 and side plates (not shown, to reveal the internal components) forming an enclosure that may fully enclose the moving components in the control-box 3. A hinged mass 5 is moveab!y supported on the structural frame 4. The hinged mass 5 can move rearward relative to the structural frame 4, as the structural frame accelerates forward, such as in the event of an impact impulse provided to the truck 1 when another vehicle collides with the crash cushion 2, or the rear of the truck, in the event no crash cushion is present.

The hinged mass 5 comprises a link assembly integrally formed as part of the hinged mass. The link assembly moveably supports the hinged mass 5 on the structural frame 4 by the hinge pin 6, which constrains the path through which the hinged mass 5 is able to move. The forward position of the hinged mass 5 is limited by contact with a control lever assembly 7. The control box 3, in use, is positioned on the truck 1 so that the path that the hinged mass 5 can travel is aligned with the forward direction of the vehicle. The control-lever assembly 7 is mounted to the structural frame 4 by a pivot pin 8 about which the control-lever can rotate. The system also comprises a biasing element configured to impart a biasing force on the hinged mass. The biasing element is in the form of an extension-spring 9. One end of extension-spring 9 is connected at point 10 to the mass 5. The other end of the extension-spring is connected to the control-lever assembly at spring attachment 11. The force applied by the extended spring 9 at attachment 11 rotates control-lever 7 about pivot pin 8 until blocked by the mass, or the structural frame. When the vehicle is not involved in a collision, the extension-spring holds the mass against the control-lever thus immobilizing both the mass and the control-lever in a non-braking configuration in which the control lever is prevented from rotating further. In alternative embodiments there may be separate springs or other biasing elements for each of the hinged mass and control-lever. In some embodiments the hinged mass may be biased towards the non- braking configuration by a spring connecting the hinged mass to the structural frame. In some embodiments the control-lever may be biased towards the braking activation device by its own weight. It is particularly advantageous to use a single spring to bias both the hinged mass forwards, and the control-lever towards the braking activation device, as will be described. Furthermore, it is

advantageous for the valve to be biased in the closed position such that a reasonable force is required to open the valve, as will be described. Spring 9 biases both the hinged mass 5 forward, and the control- lever 7 towards the valve 13. If the spring 9 fails, there will be reduced resistance on the hinged mass 5, which may then move sufficiently rearward to allow the control-lever 7 to contact the valve 13.

However, as the spring 9 has failed, there is no longer any external bias on the control-lever to depress the valve 13. There may be some bias due to the weight of the control-arm 7, but in preferred embodiments the valve 13 requires a greater force to be opened than can be applied by the weight of the control-arm 7 alone. This mitigates the risk of accidental activation of the brakes in the event the spring 9 fails.

The control-lever may comprise a component to facilitate relative moment of the control-lever on the contact surface of the hinged mass. A roller 12 on the control lever 7 is moveably supported on a contact surface on the hinged mass 5. In alternative embodiments, a low friction pad or similar component may be mounted to the control lever to facilitate movement.

The control box 3 also comprises a braking activation device in the form of a pneumatic valve 13 which, as will be described, can be depressed to activate the air brakes of the truck 1. The pneumatic valve 13 is mounted on a bracket on the front of the control box frame 4. In the non-braking configuration shown in Figure 2, the control-lever 7 is not able to rotate far enough to depress the normally closed pneumatic valve 13, so the valve remains closed, and the vehicle's brakes remain inactivated.

Advantageously, if the spring 9 fails without the truck being impacted, the hinged mass 5 remains blocking the control-lever 7, and the vehicle's brakes are not applied inadvertently. This mitigates the risk of accidental application of the brakes, which would be hazardous if the vehicle is being driven.

Figure 3a shows a representation of the control box 3 while the structural frame 4 is accelerating forward during a collision from another vehicle to rear of the truck 1. The force of the collision accelerates the truck l and the control box frame 4 forwards. As the movement of the control-lever 7 is constrained by contact between the roller 12 and the hinged mass 5, point 11 accelerates forward with the structural frame 4, extending the spring 9, and thereby accelerating the point 10 and the therefore the mass 5 in the same direction. In this preferred embodiment the extension spring 9 has an initial force required for extension. The spring is selected and mounted so that there is an initial tension sufficient to hold the hinged mass 5 and control lever 7 in the non-braking configuration until a predetermined acceleration of the structural frame 4. During rearward movement of the hinged mass 5, the spring tension may increase, however the effective moment arm of the spring will be reduced. The position of the spring attachment 10 on the mass 5 is chosen to keep the restraining force on the hinged mass 5 approximately the same through the range of motion of the hinged mass 5. The predetermined acceleration required for the mass to move rearward is chosen to be lower than the acceleration expected to be experienced by the truck during a collision, to enable the mass to move during a collision and apply the brakes if the duration of the collision impulse exceeds a predetermined length of time. The predetermined acceleration is also chosen to be higher than the acceleration expected during normal operation of the vehicle, such as normal traffic management duties. The acceleration of the truck having an attenuator may not change significantly during the first 0.2 seconds of a collision, however the duration of the impact impulse does increase with the mass and velocity of the vehicle that collides with the truck's attenuator.

The shape of the mass 5 causes the control-arm 7 to remain stationary relative to the control box frame 4 during the early stages of the collision, so that the normally closed pneumatic valve 13 is not depressed by the control-lever 7, and the valve 13 remains closed. If the duration of the collision impulse is short, the acceleration of the vehicle will cease before the mass reaches the rear of the control box, and the tension created by the elongation of the spring 9 will return the mass to the position shown in Figure 2.

Figure 3b shows a cross section A-A plan view of the control box 3. In this exemplary embodiment the hinged mass 5 is formed from steel plate, and is profile cut to the appropriate shape. The link assembly formed by the upper portion of the hinged mass is welded to the steel hinge 6. The roller 12 rolls along the edge of the steel plate from which the mass is formed. The control lever 7 is formed from two rolled hollow section steel (RHS) members with profile cut side plates welded to the RHS members. Alternatively the control-lever may be a one-piece casting.

Figure 4 shows the control box after a sufficiently severe collision in which the hinged mass 5 has overcome the biasing force of the spring 9 and the hinged mass 5 and control-lever 7 have moved from the non-braking configuration to the braking configuration. The mass 5 has moved far enough rearward to release the control-lever assembly 7 and allow the spring to rotate the control-lever further and contact the pneumatic valve 13 to open it. This allows air from an air brake reservoir 15 (represented in Figure 5) to apply the vehicle service brakes via shuttle valves 16 and 19 (also represented in Figure 5).

The inertia of the hinged mass restricts the acceleration of the mass rearward and delays application of the brakes until the mass has moved far enough to release the control-lever. The distance that the mass must move before the control-lever is released can be chosen prior to manufacture to provide the desired performance characteristics. If the distance is very small, only a very brief collision impact (corresponding to a slow and/or small vehicle) will be necessary to apply the brakes. If the distance is greater, then a collision impact of greater duration will be necessary to apply the brakes. This longer duration impact impulse could be generated by a heavier vehicle and/or a vehicle travelling at a higher speed. The hinged mass and control-lever move from the non-braking configuration to the braking configuration when the mass has moved the predetermined distance and allowed the control-lever to activate the braking activation device. The rate of acceleration of a truck having a truck mounted attenuator can be relatively low, given the ability of the attenuator to deform over a distance. For this reason, it is advantageous to take both the expected magnitude and duration of an acceleration caused by an impact into account when designing an emergency brake activation system according to the invention. Therefore, the shape of the hinged mass and control arm are chosen so that while the structural frame must experience a predetermined acceleration, the hinged mass must also move rearward through a predetermined distance, before the components move from the non-braking configuration to the braking configuration. A mechanical or electronic AIB system that does not take the duration of an impact impulse into account would be more likely to initiate braking and cause an accident when application of the brakes was not required. Once the hinged mass 5 and control lever 7 have moved to the braking configuration, the spring 9 and the shapes of the hinged mass 5 and control lever 7 holds the control lever assembly 7 in a position that prevents the hinged mass 5 returning toward the front of the control box 3, thus locking the normally closed pneumatic valve 13 in the open position and keeping the vehicle service brakes applied. In this way, the control box 3 remains locked in the braking configuration after the hinged mass 5 and control- lever 7 have moved from the non-braking configuration to the braking configuration.

The control box mechanism can be mechanically reset to the non-braking configuration, by rotating the control lever 7 against the spring 9 to release the hinged mass 5. This allows the spring 9 to return the hinged mass 5 to the position shown in figure 2. A screwdriver 14 or other tool can be inserted through a hole in the bottom of the control box 3 and used to rotate the control lever 7. Any suitable tool, bar or levering means may be used. It is advantageous to be able to reset the control box, to facilitate testing of the correct functioning of the control box before it is installed in a vehicle, or at other times such as scheduled intervals at which time the control box is removed from the vehicle for testing. The pneumatic circuit can be tested by separating (e.g. unbolting) the valve from the control box and manually depressing the valve.

It will be appreciated that the hinged mass is an element of the emergency braking system that, in use, due to its weight and/or shape can block or otherwise prevent the control-lever from activating the brakes on the vehicle, yet will move in response to a predetermined acceleration of the structural frame, for a predetermined time, to allow the control-lever to activate the brakes on the vehicle.

Furthermore, the hinged mass may be hinged in the sense that it is connected to a structural frame with a hinge, although alternatively it may be hinged in the sense that it is pivotally supported on the frame, e.g. in the manner of a hinge, with a component other than a hinge, such as a rotatable bolt, bearing(s), and the like.

It will be appreciated that various properties of the components need to be chosen appropriately so that the hinged mass and control lever move from the non-braking configuration to the braking configuration as a result of a predetermined acceleration. For example, many of: the mass and geometry of the hinged mass, the stiffness of any biasing elements, the mass and geometry of the control-lever arm, the static and dynamic friction between the components, the mass of the truck and the ability of any attenuator mounted on the truck to absorb energy, can be taken into account when designing an emergency activated brake system according to embodiments of the invention, to facilitate activation of the brakes based on a predetermined acceleration of the truck. The predetermined acceleration itself may be dictated by a legal or accepted standard. Based on the disclosure herein, a skilled person is able to balance the various factors to achieve the desired effects through routine design and/or workshop experimentation.

While the broader aspects of the invention may be applied to activation of any suitable type of braking system, the invention is particularly suited to vehicles equipped with air brakes.

Figure 5 shows a schematic representation of a pneumatic circuit that can used with embodiments of the invention, such as the preferred embodiment described with reference to control box 3 having valve 13. This pneumatic circuit is connected to the existing vehicle air brake system at three points. The air supply comes from an existing air brake reservoir 15 on the vehicle. Shuttle valve 16 is installed between the existing vehicle foot valve 17 and the vehicle air brake circuit for the front axle service brakes 20. Shuttle valve 19 is installed between the foot valve 17 and the vehicle air brake circuit for the rear axle service brakes 20.

A 3/2-way normally open solenoid valve 21 can be installed between the normally closed valve 13 and the shuttle valves. Valve 21 is optional and does not have any effect on the vehicle brake system until after a collision has caused the control box mechanism to open the valve 13.

When the normally-closed pneumatic valve 13 is opened by the control lever assembly 7 during a collision, air from the air brake reservoir 15 flows to the shuttle valves 16 and 19 via valves 13 and 21 and applies all of the vehicle service brakes. The service brakes remain applied until the air pressure on the shuttle valves is removed. Any ABS or EBS system installed on the vehicle is able to function normally.

In embodiments in which a valve such as solenoid valve 21 is installed, the driver can regain full control of the vehicle brakes at any time, if he/or she is able, by energizing the solenoid via a switch in the cab. This blocks the air supply from the air reservoir 15 and exhausts the air from the shuttle valves to atmosphere. The vehicle can then be moved away from the scene of the accident.

It will be appreciated by skilled addressee that the term 3/2-way may also encompass valves that are not known specifically as 3/2-way valves, but that are implemented to provide the same function as a 3/2-way valve. For example, any suitable valve implemented with at least three external ports and which can provide at least two combinations of valve open/closed positions could be used in various embodiments of the invention. It will be appreciated that in some alternative embodiments of the invention, only rear axle brakes may be connected to the system.

In one such alternative embodiment of the invention, the pneumatic circuit to which the control box is connected may be simplified and enable application of the truck's parking brakes rather than the service brakes. While it has been noted that it is preferred to apply the service brakes, this embodiment is a lower cost option, as the pneumatic circuit is simplified.

The parking brakes on truck are typically controlled by the driver with a hand brake valve in the cab of the truck. To disengage the parking brakes, the hand brake valve in the cab is opened, which provides a small volume of air through a parking brake signal line to a parking brake relay valve, which causes the parking brake relay valve to provide air from the main air reservoir to the parking brakes, compressing the springs and thereby disengaging the parking brakes.

If the driver wishes to engage the parking brakes, the driver can close the hand brake valve in the cab, which exhausts the air in the parking brake signal line, which causes the parking brake relay valve to exhaust the air that had been provided to the spring brakes, letting the springs extend and thereby engaging the parking brakes.

Figure 10 shows a schematic illustration of a pneumatic circuit which could be used in such an alternative embodiment of the invention on a typical truck. An AIB module such as control box 3, as described previously, is coupled with a valve 63, which in this embodiment is a normally open 3/2 way pneumatic valve. It is normally open so that it does not interrupt the connection between a hand brake valve 61 and a parking brake relay valve 62. This connection forms a parking brake signal line. By connecting the valve 63 to the parking brake signal line between the hand brake valve 61 and the parking brake relay valve 62, in a normally open position, the valve 63 can then be closed by the control box 3 in an emergency, and exhaust the air in the parking brake signal line to provide the same effect as if the hand brake valve 63 had been closed by the driver during normal operation of the truck. It will be appreciated that invention provides for a general method of activating an emergency braking system, comprising the steps of imparting a biasing force on a mass associated with a control-lever such that the biasing force directs the mass and associated control-lever towards an inactivated position in which the vehicle's brakes are not activated, and then moving the mass and associated control-lever against the biasing force, upon an impact occurring, when the force of the impact is sufficient to overcome the biasing force, to cause the mass and control-lever arm to move towards an activated position which activates the emergency braking system.

Figure 6 shows a machine that can be employed to test control boxes according to embodiments of the invention, and to demonstrate that each control box functions correctly before it is installed on a vehicle. The machine comprises a lever 24 to which the control box can be attached. A weight 23 is connected to the lever. The machine comprises a release mechanism 22, which when activated, allows the weight 23 to fall a short distance onto a shock-absorbing platform (not shown), which for example could be two wooden planks. The distance that the weight falls can be varied, by changing the thickness of the platform. The weight 23 is attached to a lever 24. The control box 3 under test is suspended at the other end of the lever. The control box is further away from lever pivot 25 than the weight so the acceleration of the control box and the distance travelled is greater than that of the weight. By appropriate choice of lever pivot lengths (e.g. the positions of the weight and control box on the lever), along with the mass of the weight and the distance that the weight can fall it is possible to simulate a predetermined acceleration of the control box. The predetermined acceleration may correspond to an expected acceleration of a truck equipped with attenuators certified to withstand a standardised test collision, for example an NCHRP 350 test level 1 (Tl) collision, or an NCHRP 350 test level 2 (T2) collision. The machine can be reset for the next test by pushing down on the long arm of the lever.

Preferably, the control box 3 under test is mounted on a carriage (not shown) guided by vertical tracks (not shown) and the attachment to the lever is flexible so that the carriage would continue to move vertically in the vertical tracks after the initial impulse imparted by the falling weight. The maximum height reached by the carriage can be recorded and used to calculate the maximum velocity reached during the test, and the corresponding rate of acceleration. This provides confirmation that the test machine is providing the required impulse. A ballast weight can be attached to the carriage to reduce the rate of acceleration of the carriage, thus providing a means to establish GO and NO-GO criteria when certifying AIB modules.

Figure 7 shows a control box 43 of an emergency activated brake system according to an alternative embodiment of the invention, and will be described with reference to a truck on which the control box 43 is mounted.

The control-box 43 includes a structural frame 44 and fully encloses the moving components in the control-box 43. A mass 45 can move rearward relative to the truck when the truck is accelerated forward by the impact impulse when another vehicle collides with the crash cushion or the rear of the truck. The mass 45 has a slab like body. The path of the mass is constrained by two link assemblies 46 and 47. One end of link-assembly 46 pivots about point 48 on the control box frame and the other end pivots about point 49 on mass 45. One end of link-assembly 47 pivots about point 50 on the control box frame and the other end pivots about point 41 on the mass 45. The control box is aligned so that the path of the mass is parallel to the forward direction of the truck. In Figure 7, the mass 45 and control- lever 47 are in a non-braking configuration.

A control-lever 52 rotates about pivot 53 on the control box frame. One end of extension spring 54 is connected to point 55 on link assembly 57. The other end of the extension-spring is connected to the control-lever at spring attachment 56. The tension in the extended spring rotates control-lever 52 until a roller 57 on the control-lever 52 contacts mass 55. When the vehicle is not involved in a collision, the tension in the extension spring holds the mass against the control-lever thus immobilizing the mass. The control-lever is not able to rotate far enough to depress the roller on a normally closed pneumatic valve 58, so the valve remains closed. The pneumatic valve is mounted on a bracket on the front of the control box frame.

Figure 8 shows the position of the components during a collision from the rear. The force of the collision accelerates the vehicle and the control box frame forwards. The spring 54 accelerates the mass in the same direction. If the spring tension is selected so that the rate of acceleration of the mass is less than the rate of acceleration of the vehicle during a collision, then the mass will move rearward relative to the control box. The shape of the mass causes the control-arm to remain stationary relative to the control box frame during the early stages of the collision, so that the normally closed pneumatic valve remains closed. If the duration of the collision impulse is short, the acceleration of the vehicle will cease before the mass reaches the rear of the control box and the spring will return the mass to the position shown in Figure 7.

Figure 9 shows the control box when the collision impulse lasts long enough for the mass to reach the rear of the control box, and so the hinged mass and control arm have moved to the braking configuration. The control-arm is then able to rotate further and depress the roller on the normally closed pneumatic valve 58. This opens the pneumatic valve and allows air from an air brake reservoir to apply the vehicle service brakes via shuttle valves.

The spring holds the control arm in a position that prevents the mass returning toward the front of the control box thus locking valve 58 in the open position and keeping the vehicle service brakes applied. The control box can be reset by inserting a screwdriver 59 through a hole in the side of the control box, and lifting the end of the control lever 52 to release the mass and allow the spring to return it to the position shown in Figure 7. Any suitable tool, bar or levering means may be used.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference. Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world. The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.




 
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