GB2173560A - Emergency brake actuating system - Google Patents

Abstract

The brake actuating system for a motor vehicle includes a relay valve 50 or pilot valve 26 for operating the vehicle brakes which relay (pilot) valve is actuated by an actuator valve in the form of a solenoid valve or pneumatically-operated valve operable if the vehicle contacts an obstacle when reversing. The system may be for a trailer and comprise an electrical sensor in the form of a reversing impact switch (13, Figure 1) mounted on a bumper bar and connected to a relay switch (15) - the relay switch causes solenoid valve (9) to open to actuate relay valve (3) connected to an emergency line (1). Figures 2, 3 show other systems, involving solenoid valves, Figure 3 having spring brake chamber 41, and Figure 4 shows a modification of Figure 3 with a pneumatically operated valve (60) and pneumatic sensor (61). <IMAGE>

Description

SPECIFICATION Emergency brake actuating system This invention relates to an emergency brake actuating system for a motor vehicle, and in particular to an emergency brake actuating system for a commercial motorvehicle.

Frequently, accidents are caused when reversing motor vehicles, and damage and injury can be caused when the rear of the vehicle unexpectedly comes into contact with an obstacle such as a person or another vehicle. Various proposals have been made in the past to provide an automatic warning to the driver when his vehicle contacts an obstacle, or to apply the vehicle brakes automatically in the event of impact with an obstacle. The difficulty with a visual or acoustic warning signal is that the driver may not be able to react in time to apply the brakes. Known automatic braking systems are difficult to install on existing vehicles.

The present invention provides an emergency brake actuating system for a motor vehicle, the system comprising a relay valve for operating the vehicle brakes, an actuator valve for actuating the relay valve, and operating means for operating the actuator valve, the arrangement being such that said means is actuated, in the event that the vehicle contacts an obstacle when reversing, to pass a signal to the actuator valve and the relay valve, thereby causing the vehicle brakes to be applied.

In a preferred embodiment, the actuator valve is a pneumatically-operated pilot valve, and the operating means is a pneumatic sensor, the output of the pneumatic sensor being applied to the pilot line of the pilot valve.

Alternatively, the actuator valve is a solenoid valve, and the operating means is constituted by an electrical relay switch and an electrical sensor, the relay switch operating the solenoid valve, and the sensor actuating the relay switch. In this case, the solenoid valve may be normally closed, but in the open position passes fluid from a service line to the relay valve, and the relay valve may be effective to pass fluid from an emergency line to the vehicle brakes when the relay valve is actuated by the solenoid valve.

Advantageously, a pressure control valve is included in the line leading from the solenoid valve to the relay valve. Preferably, a double check valve is included in the service line, the double check valve being effective to control the relay valve.

Preferably, the relay valve is provided with an exhaust port which is connected to a line leading to the vehicle brakes when the relay valve is actuated by the actuator valve, the venting of said line being effective to operate the brakes.

Advantageously, a differential valve and a quick exhaust valve are included in the line leading from the relay valve to the brakes, the quick exhaust valve having an exhaust port which is arranged to open when the pressure fluid passing through the quick exhaust valve drops by about 2 p.s.i.

Preferably, the electrical relay switch is provided with two sets of contacts, a first set of contacts being connectible to the reverse light circuit of the vehicle for powering the electrical relay switch, the second set of contacts being donnected to the electrical detector.

The invention also provides a vehicle system including vehicle brakes, a fluid service line for said brakes, and an emergency brake actuating system as defined above.

Conveniently, the vehicle brake system further comprises a hand brake control valve which is connected to the relay valve via inlet and outlet ports of the actuator valve. Preferably, the service line leads to the relay valve via a multi circuit protection valve.

The sensor is preferably fitted to a bumper bar mounted at the rear of the vehicle, a preferred form of bumper bar being as described in our British Patent Specifications Nos. 2107909 and 2122551.

Where the sensor is electrical, it may be an impact switch mounted in a protected position, for example as mounted at 17 in Figure 2 of British Patent Specification No. 2122551.

In addition to applying the brakes, the electrical detector may also actuate a visual or sound warning device when the bumper bar touches an obstacle.

Three forms of emergency brake actuating system, each of which is constructed in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisa lay-out diagram showing the modification of the brake system of an articulated vehicle to incorporate the first form of emergency brake actuating system; Figure 2 is a view of a lay-out drawing showing the modification of the brake system of a rigid vehicle to incorporate the second form of emergency brake actuating system; Figure 3 is a lay-out diagram showing the modification of the brake system of a rigid vehicle to incorporate the third form of emergency brake actuating system; and Figure 4 is a scrap view showing a modification of part of the third form of emergency brake actuating system.

Referring to the drawings, Figure 1 shows the standard braking system of an articulated trailer, as modified by the first form of emergency brake actuating system. The standard braking system includes an emergency line 1 and a service line 2, the service line 2 being connected to an emergency relay valve 3 via a check valve 4. Actuation of the vehicle brakes in the normal way causes pressure to be applied, via the check valve 4, to the relay valve 3.

The relay valve 3 then opens, and allows airto pass from a reservoir 3a to the vehicle brakes along a brake line 5.

In accordance with the invention, the standard system is modified by introducing a three-way (tee) connector 6 in the emergency line 1, and connecting the third port of the tee connector to the inlet port 10 of a solenoid valve 9, via a line 7 and a pressure control valve 8. The valve 8 is set to close at pressures below about 65 psi, so as to protect the main braking circuit in the event of a leakage of air.

The solenoid valve 9 has an outlet port 11 which is connected, via a line 12, to a double check valve 4 (which replaces the standard check valve). Thus, opening of the solenoid valve 9 will allow air to pass from the emergency line 1 through the valves 8 and 9, and this will have the effect of actuating the relay valve 3, and applying air to the vehicle brakes.

An electrical sensor in the form of a reversing impact switch 13 is mounted on the support of a vehicle bumper bar (not shown), so that, when the bumper bar is pivoted, the switch 13 is connected, via a junction box 14, to a three-pole relay switch 15.

As can be seen, the relay switch 15 has connections to the solenoid valve 9 and to contacts 16 which are connected, via the reverse light circuit of the vehicle to the DC supply from the vehicle battery (not shown). In addition, the relay switch 15 is connected to a warning device 17 which gives an audible signal when the relay switch 15 is actuated. As will be appreciated, on actuation of the impact switch 13, the relay switch 15 is operated to connect the electrical supply from the contacts 16 to the solenoid valve 9, thereby causing the solenoid valve to open. As a consequence, pressurised fluid can flow from the emergency line 1, via the line 7 and the valves 8 and 9, to the double check valve 4, and hence actuate the relay valve 3 and apply the brakes.

Figure 2 shows a lay-out diagram suitable for a rigid vehicle which does not possess an emergency line. In this case, the line from the foot valve 20 is connected to a double check valve 21 to cause pressurised fluid to flow to the vehicle brake valve 21 to cvause pressurised fluid to flow to the vehicle brake actuators 22. A service reservoir 23 is protected by a pressure control valve 24 set at 65 psi, and is connected, via a line 25, to a pilot valve 26. The pilot valve 26 is normally in the closed position, but on operation will allow fluid to pass from the service reservoir 23 to the double check valve 21, and hence apply the vehicle brakes. The electrical arrangement of Figure 2 is the same as that shown in Figure 1, in that terminals 27 are connected to a reversing impact switch (not shown, but similarto the switch 13 of Fig. 1), and to a three pole relay switch 28.Terminals 29 connect the relay switch 28, via the reverse light circuit of the vehicle, to the battery supply of the vehicle. The output from the relay switch 28 is connected to a solenoid valve 30 which is normally closed, but, when open, is able to pass fluid from the line 25 through a branch line 31 to the pilot valve 26. The effect of applying pressurised fluid to the pilot valve 26 is to open this valve, and allow fluid to pass from the service reservoir 23 to the vehicle brakes. Thus, it will be appreciated that, on operation of the reverse impact switch, the relay switch 28 will be actuated to cause the solenoid valve 30 to open. This, in turn, will cause the pilot valve 26 to be operated, and pass fluid directly from the service reservoir 23, via the double check valve 21, to the vehicle brakes, and hence apply the vehicle brakes.

Figure 3 shows a standard braking system of a rigid motor vehicle as modified bythethirdform of emergency brake actuating system. In this embodiment the emergency brake system is included in a standard hand brake circuitforthe rear wheels of a rigid motor vehicle. This standard system includes spring brake chambers 41 for applying the vehicle rear brakes (not shown), a quick exhaust valve 42, a differential valve 43, a multi circuit protection (MCP) valve 44, and a hand brake control valve (lock actuator) 45. Each chamber 41 is connected to the quick exhaust valve 42 by a respective line 46, and the hand brake control valve 45 is connected to the differential valve 43 by a line 47. The MCP valve 44 is supplied with pressurised fluid (air) by a service line (not shown).The standard (unmodified) hand brake circuit, takes its supply direct from the MCP valve 44 through the hand brake control valve 45, and then to the spring brake chambers 41 via the differential valve 43 and the quick exhaust valve 42. The quick exhaust valve 42 has an exhaust port 42a, and the hand brake control valve 45 has an exhaust port 45a.

Each of the spring brake chambers 41 has two diaphragms, a first of which (not shown) is acted upon, via a foot brake line 48, the MCP valve 44 and the service line, by a standard foot brake pedal. The second diaphragm 41a of each chamber 41 is acted upon by a strong spring (not shown), which tends to apply the associated brake; and by the pressure of fluid in the associated line 46, which tends to hold the associated brake in the non-operative (off) position. Movement of the hand brake control valve 45 to is "on" position vents the second diaphragm 41 a of the chambers 41 to atmosphere via the exhaust port 45a, and hence results in a rapid application of the rear brakes of the vehicle.

The emergency brake actuating system of this embodiment introduces a control box 49 and a relay valve 50 into the line 47, and 9 main feed line 51 leads from the MCP valve 44to the relay valve 50 via a tee connector 52. The relay valve 50 has an exhaust port 50a. The control box 49 includes a solenoid valve 53 and a relay switch 54. The control box 49 is provided with inlet and outlet ports 53a, 53b for the solenoid valve 53, these ports being connected to the line 47.The relay switch 54 has first and second sets of contacts 54a and 54b, the first set of contacts 54a being connected to a 24 volt power supply branching offthe reverse lightcircuit(not shown) of the vehicle, and the second set of contacts 54b being connected to an electrical sensor in the form of a reversing impact switch (not shown, but similar to the switch 13 of Figure 1) mounted on the support of a vehicle bumper bar (not shown).

The emergency brake system of Figure 3 operates in the following manner. Once reverse gear is selected by the driver of the vehicle, the relay switch 54 is primed by the 24 volt supply from the reverse light circuit. Ifthe bumper bar of the reversing vehicle then strikes an obstacle, it will pivot so as to close the reversing impact switch. This will then change over the solenoid valve 53 so that the signal line leading from the outlet port 53b to the relay valve 50 is vented, via a port 53a, to atmosphere.

This results in the spring brake chambers 41 being connected to the exhaust port 50a of the ralay switch 50. After a pressure drop of about 2 p.s.i., the quick exhaust valve 42 is actuated, so that the spring brake chambers 41 are connected to the exhaust port 42a of the quick exhaust valve. This ensures a rapid venting of the spring brake chambers 41, and hence a rapid application of the rear brakes of the vehicle. As with the embodiment of Figure 1, the relay switch 54 may also actuate a warning device (not shown, but similar to the device 17) which gives an audible and/or visual warning to the driver.

The addition of the emergency brake system does not impede the normal operation of the hand brake circuit. Thus, actuation of the hand brake control valve 45 vents the line 47 to the atmosphere via the exhaust port 45a. This, in turn, vents the signal line leading from the outlet port 53b of the solenoid valve 53 to the relay valve 50. Consequently, the spring brake chambers 41 are vented to atmosphere - initially via the exhaust port 50a of the relay valve 50, and then via the exhaust port 42a of the quick exhaust valve 42.

The emergency brake actuating system of the Figure 3 embodiment has two main advantages.

Thus, it is easy to modify the existing brake circuitry of a motor vehicle to incorporate this type of emergency brake actuating system, and the emergency brake actuating system itself is effective to produce a particularly rapid emergency braking action.

Figure 4 shows an alternative to the control box 49 of the Figure 3 embodiment. Thus, Figure 4 shows a pneumatically-operated pilot valve 60 positioned in the line 47 leading from the hand brake actuator valve 45 to the relay valve 50. The valve 60 has an inlet port 60a, an outlet port 60b and a vent port 60c.

The valve 60 is controlled by a pneumatic sensor 61d which creates pressure in a pilot line 62 leading to the valve 60. The sensor 61 is positioned on the support of the vehicle bumper bar so that, upon impactwith an obstacle when reversng,the pneumatic sensor 61 actuates the valve 60. This, in turn, results in the venting of the signal line leading from the outlet port 60b to the relay valve 50, and hence to actuation of the brake in the manner described above with reference to Figure 3.

The main advantage of the modified circuit arrangement of Fig. 3 is that it is totally pneumatic, so that there is no danger of electric sparks being generated by the reverse impact switch, which sparks could lead to a fire or an explosion should the impact result in release of fuel.

Claims (15)

1. An emergency brake actuating system for a motor vehicle, the system comprising a relay valve for operating the vehicle brakes, an actuator valve for actuating the relay valve, and operating means for operating the actuator valve, the arrangement being such that said means is actuated, in the event that the vehicle contacts an obstacle when reversing, to pass a signal to the actuator valve and the relay valve, thereby causing the vehicle brakes to be applied.

2. A system as claimed in claim 1, wherein the actuator valve is a pneumatically-operated pilot valve, and wherein the operating means is a pneumatic sensor, the output of the pneumatic sensor being applied to the pilot line of the pilot valve.

3. A system as claimed in claim 1, wherein the actuator valve is a solenoid valve, and wherein the operating means is constituted by an electrical relay switch and an electrical sensor, the relay switch operating the solenoid valve, and the sensor actuating the relay switch.

4. A system as claimed in claim 3, wherein the solenoid valve is normally closed, but in the open position passes fluid from a service line to the relay valve.

5. A system as claimed in claim 3 or claim 4, wherein the relay valve is effective to pass fluid from an emergency line to the vehicle brakes when the relay valve is actuated by the solenoid valve.

6. A system as claimed in any one of claims 3 to 5, wherein a pressure control valve is included in the line leading from the solenoid valve to the relay valve.

7. A system as claimed in claim 4, or in either of claims 5 and 6 when appendant to claim 4, wherein a double check valve is included in the service line, the double check valve being effective to control the relay valve.

8. A system as claimed in claim 2 or claim 3, wherein the relay valve is provided with an exhaust port which is connected to a line leading to the vehicle brakes when the relay valve is actuated by the actuator valve, the venting of said line being effective to operate the brakes.

9. A system as claimed in claim 8, wherein a differential valve and a quick exhaust valve are included in the line leading from the relay valve to the brakes.

10. A system as claimed in claim 9, wherein the quick exhaust valve has an exhaust port which is arranged to open when the pressure fluid passing through the quick exhaust valve drops by about 2 p.s.i.

11. A system as claimed in any one of claims 8 to 10 when appendantto claim 3, wherein the electrical relay switch is provided with two sets of contacts a first set of contacts being connectible to the reverse light circuit of the vehicle for powering the electrical relay switch, the second set of contacts being connected to the electrical detector.

12. An emergency brake actuating system substantially as hereinbefore described with reference to, and as illustrated by, Fig. 1, Fig. 2, Fig.

3 or Fig. 3 as modified by Fig. 4 of the accompanying drawings.

13. Avehicle brake system including vehicle brakes, a fluid sevice line for said brakes, and an emergency brake actuating system as claimed in any one of claims 1 to 12.

14. A vehicle brake system as claimed in claim 13 when appendant to any one of claims 8 to 12, further comprising a hand brake control valve which is connected to the relay valve via inlet and outlet ports of the actuator valve.

15. A vehicle brake system as claimed in claim 14, wherein the service line leads to the relay valve via a multi circuit protection valve.