CA1305986C - Braking system - Google Patents
Braking systemInfo
- Publication number
- CA1305986C CA1305986C CA000514791A CA514791A CA1305986C CA 1305986 C CA1305986 C CA 1305986C CA 000514791 A CA000514791 A CA 000514791A CA 514791 A CA514791 A CA 514791A CA 1305986 C CA1305986 C CA 1305986C
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- Canada
- Prior art keywords
- pump
- vehicle
- braking system
- valve
- air
- Prior art date
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Abstract
ABSTRACT
BRAKING SYSTEM
An auxiliary braking system for a vehicle comprises means arranged to be actuated by the engagement of reverse gear of the vehicle, said means being connected to operate a valve, and a detector connected to operate the same valve, or another valve arranged in series. The valve or valves are arranged in a fluid circuit including a pump for generating a pressurised fluid. This arrangement enables the valve or valves to permit pressurised fluid to flow and to cause actuation of the braking system when the valves is or are in an operated condition,
BRAKING SYSTEM
An auxiliary braking system for a vehicle comprises means arranged to be actuated by the engagement of reverse gear of the vehicle, said means being connected to operate a valve, and a detector connected to operate the same valve, or another valve arranged in series. The valve or valves are arranged in a fluid circuit including a pump for generating a pressurised fluid. This arrangement enables the valve or valves to permit pressurised fluid to flow and to cause actuation of the braking system when the valves is or are in an operated condition,
Description
---`" 1305986 ~RAKING SYSTE~S
This invention relates to braking systems and more particularly concerns such systems which are operable to actuate the brakes o~ a vehicle when it is in a reverse condition.
It is known to operate the brakes of a vehicle by means of a system which is operable by a reverse gear actuated switch and a detector at the rear of the vehicle the arrangement being such that the brakes are activated onl~ when the detector contacts an object and the switch is actuated by engagement of reverse gear.
Many prior proposals relate to air-operated bra~ing systems but it is desirable to produce a reverse braking system which can be used with a hydraulic braking system.
There have been some prior prcposals for such systems but none has achieved commercial success.
In particular U.S. Patent No. 2,588,815 (Fasolino) describes various reverse braking systems using electrical switches operated by the vehicle gear lever and a detector at the rear of the vehicle to operate a 20 device which causes operation of the brakes. In one embodiment the device is a power solenoid acting on the brake pedal linkage and in another embodiment is a solenoid valve arranged to apply vacuum from the intake manifold to a pneumatic cylinder connected by a flexible 25 cable to the brake pedal linkage.
U.K. Patent No. 1470129 (Ebbeson et al) describes a similar system actuated by electrical switches and an electromagnetically controlled pneumatic valve. This valve is connected to the vacuum servo of the braking 30 system of the vehicle to control the application of atmospheric pressure to the vacuum chamber of the servo and thereby cause the brakes to be actuated whilst the electrical switch controll~d by the detector is actuated.
The present invention provides an improved reverse ,, ,,," , .. ..
, -` 1305986 actuated auxiliary braking system ~or use with hydraulic vehicle braking systems.
According to the present invention I provide an auxiliary braking system for a vehicle which system comprises means arranged to be actuated by the engagement of reverse gear of the vehicle, said means being connected to operate a valve, a detector connected to operate a valve, said valve or vaLves being arranged in a fluid circuit including a pump for generating pressurised fluid whereby when said valve or valves is or are in an operated condition they permit pressurised fluid to flow and to cause actuation of the braking system.
The pressurised fluid may be a liquid or gas and is preferably air.
Preferably the reverse gear actuated means is a ~ -switch.
The reverse gear actuated switch and the detector may be connected to operate a single valve or two valves arranged in series.
The flow of pressurised fluid may be utilised to pressurise the hydraulic system of the vehicle, either directly or indirectly, or may be utilised to operate mechanical means to actuate the brakes of the vehicle.
In one embodiment of the invention the pressurised fluid is used to operate a hydraulic cylinder which is connected into the hydraulic braking circuit of the t vehicle, either as an auxiliary cylinder, as an existing cylinder in the circuit or as a combination of both with t the cylinders arranged in series or in parallel.
Alte~natively the hydraulic cylinder may be used to operate mechanical means to actuate the brakes; for example it may operate the linkage between the brake pedal and the servo of a servo-assisted braking system.
A simple arrangement is to include the cylinder in a linkage so that when the cylinder is contracted the brake . . .
~30S9186 linkage operates normally but when the cyLinder is expanded it operates the brakes independently of the foot brake pedal.
In a further embodiment the auxiliary braking system further comprises a mechanical arrangement for operating the braking system. The mechanical arrangement may include a rod connected into the existing brake circuit of the vehicle and adapted to actuate the vehicle braking system. The rod may be movable between a first position in which the braking system is not actuated, and a second position in which the braking system is actuated. A
further valve may be provided for moving the rod between the first and second positions.
In this embodiment the vehicle braking system may include a brake actuation rod connected to a brake pedal, and a piston rod for operating a hydraulic brake cylinder; the hydraulic brake cylinder operates the brakes. The rod of the auxiliary braking system can be disposed between the brake actuation rod and the piston rod, so that the brakes can be applied normally by the brake pedal, or through the auxiliary braking system.
This invention is further described with reference to the accompanying drawings, in which:-Figure 1 is a schematic diagram of one form of auxiliary braking system according to the invention;
Figure 2 is a schematic diagram of another form of the invention;
Figure 3 is a schematic diagram of yet another form of the invention;
Figure 4 is a schematic diagram of yet another form of the invention;
Figure 5 is a schematic diagram of yet a further form of the invention;
Figure 6 is a diaqram of a valve suitable for use in the system of Figures 1 to 5; and Figure 7 is a schematic diagram of yet another form , .
~3~sg~6 of the invention.
Figure 1 shows a system in which pressurisedhydraulic fluid is generated by a cylinder and connected into the existing braking circuit by means o~ an additional valve (not shown).
The circuit is based on an air-operated valve 10 which may be of the type shown in Figure 6. Control air is provided to the valve 10 along line 11 which is connected to a pneumatic detector 12 located at the rear of the vehicle. When the valve 10 is not operated the outlet is connected to atmosphere which prevents any accidental build-up of air pressure.
Pressurised air is generated by a pump 13 which is connected in an electrical circuit includinq a gear lever-operated switch 14 and a solenoid valve 15. When reverse gear is engaged pump 13 is energised and provides pressurised air through non-return valve 16 to the air-operated valve 10.
When the pneumatic detector 12 is activated, e.g. by contact with an obstruction, air in line 11 will operate valve 10 to permit pressurised air from the pump 13 to pass into the cylinder 17. This incorporates a piston 18 and piston rod 19 which is mechanically connected to a hydraulic cylinder 20.
The hydraulic cylinder 20 is a conventional type which includes a piston 21 which operates against a return spring 22 and which incorporates a valve element 23 so that when it is moved against the spring pressure it closes off the port 24 connected to fluid reservoir 25 30 and causes pressurised hydraulic fluid to be applied to the line 26 which is connected into the existing hydraulic eluid system of the vehicle by means of a valve (not shown) or by connection into the existing brake master cylinder of the vehicle.
It will be apparent that the pump 13 will generate .,, 1~05986 pressurised air only when operated by the gear lever switch 14 and thus when the vehicle is in a reversing condition. When the vehicle is not in a reversing condition the pump 13 does not operate and the valve 15 remains closed.
The pump 13 may generate noise and to this end it is preferred to locate it near the rear of the vehicle where it will act as a warning device that the vehicle is in a reversing condition.
It has been found that the valve 10 can be operated by a very small change in pressure in the line ll so that a very sensitive system is achieved.
Figure 2 shows a modi~ication of the ~system shown in Figure 1 in which the cylinders 17 and 20 are replaced by a single cylinder 27 which is operated directly by the air pressure in the line 28 from the valve 10.
A further alternative embodiment of the invention is shown schem~tically in Figure 3. The cylinder 30 is air-operated and includes an air-operated piston 31 with 20 a piston rod 32 and return spring 33. The line Z8 is connected in a circuit as shown in Figure 1 but the connection to the braking system of the vehicle is mechanical rather than hydraulic. The piston rod 32 is connected to part of the brake pedal linkage of the vehicle at 34 and the cylinder 30 is connected to the linkage at 35. Thus the linkage can be moved either by pressure of the driver's foot on the pedal 36 or by movement of the piston rod 32 in response to air pressure in the line 28 caused by simultaneous operation of the 30 gear lever switch 14 and the pneumatic detector 12.
The system can be simplified by using a single solenoid valve to replace the valves 10 and 15 in the air circuit of Figure l and an air-operated electrical switch in the electrical circuit. Such an arrangement is shown in Figure 4.
1305~86 The cylinder 40 can be similar to the cylinders 20, 27 or 30 in Figures l to 3 respectively. The pneumatic detector 12 and air line 11 are connected to an air-operated switch 41 which is connected to the solenoid valve 42. The gear lever-operated switch 14 is connected as in Figure l so as to operate pump 13 which supplies pressurised air through non-return valve 16 to the solenoid valve 42. Thus when both switch 14 and switch 41 are operated the solenoid valve will pass pressurised lO air to the cylinder 40 causing actuation of the vehicle brakes as previously described.
An electrical relay 43 may be included so that when switch 41 is operated and then released the solenoid valve 42 will remain operated until the electrical 15 circuit to the relay 43 is broken by moving the gear lever out of reverse and opening switch 14. This causes the brakes of the vehicle to remain actuated after the signal from the pneumatic detector 12 has been interrupted so that the vehicle can be moved only by 20 first disengaging reverse gear after the auxiliary brake system has been operated.
Figure 5 illustrates two further modifications which are within the scope of this invention.
Firstly, an alternative means for holding the brakes 25 on after the signal from the pneumatic detector has been released is the use of an air-operated valve 50. Whilst air pressure remains in the line 28 the valve 42 will remain operated.
Secondly, two hydraulic cylinders are used in 30 tandem. The hydraulic cylinder 20 is part of an auxiliary circuit as shown in Figure 1 but the outlet line 26 for pressurised hydraulic fluid is connected into the fluid circuit of the vehicle braking system by connecting the line 26 to the fluid reservoir inlet 52 of 35 the cylinder 51. By this means when pressurised fluid is ~l3059~l6 generated by the cyLinder 20 in response to the pneumatic detector 12 being operated, it is appLied to the master hydraulic cylinder Sl of the vehicle braking system and pressurises outlet line 53 to operate the brakes of the 5 vehicle.
Normally, the cylinder 51 is operated by means of the foot brake linkage 54 and is not affected by the existence of the auxiliary master cylinder 20 as the line 26 is closed when the cylinder is operated. Topping up Of the system is derived from the fluid reservoir 25.
It may be desirable to provide an air reservoir in the above systems so that a supply of pressurised air is available before the pump has delivered sufficient pressure to operate the system. Generally, however, I
have found that this is not necessary as the volume of the lines can be sufficient for the purpose, particularly where the pump is located at the rear of the vehicle.
The valve lO and the non-return valve 16 serve to retain the pressurised air.
In Figure 6 the valve lO is illustrated. Inlet port 64 is for pressurised air from the pump and inlet port 60 is connected to the line from the pneumatic detector 12.
When the detector is operated pressurised air is applied at inlet 60 causing the valve member 63 to move down against spring 62 causing the port 64 to be closed off from the e~haust to atmosphere (not shown) and to be connected to the outlet port (not shown) to the brake actuating arrangement (e.g. line 28 of Figure l).
A suitable valve is marketed under the name "Boostermite" Type SBV-913 which can be arranged to operate on a differential pressure of one half to three inches of water.
Figure 7 illustrates another embodiment of the invention. In Figure 7 the gear lever switch 14 is 35 connected to a power source (not shown), and also to the ~305~86 pump 13 via electrical line 70. The pump 13 is connected to a switch 71 via an electrical line 72.
The switch 71 is a low sense electrical switch, for example, the switch sold under the name HERGAIR. In an alternative embodiment the switch 71 can be replaced by a Humphrey low sense valve. The switch 71 is pilot operated; a detector 73 is connected to the switch 71 via an air line 74. Air flow through the air line 74 from the detector 73 provides the pilot operation of the switch 71. The detector 73 can include an air bag, and compression of the air bag causes air flow through the air line 74.
The switch 71 is connected to a solenoid 75 via an electrical line 76. A pilot operated relay switch 77 is connected to the solenoid 75 via an electrical line 78 and the line 76. The relay switch 77 i5 also connected to the line 70 via a line 79.
The solenoid 75 is connected to the pump 13 via an air line 80, and is provided with an exhaust 81. The solenoid 75 is connected to the relay valve 77 via an air line 82.
The relay valve 77 is connected to a further valve 83 via an air line 84. The valve 83 is pilot operated by means of the air line 84. The valve 83 shown in Figure 7 is a diaphragm air valve and includes a flexible diaphragm 8S ~hich is connected to a movable rod 86. The valve 83 has a chamber 94 which communicates with the line 84, and a separate chamber 95 which is provided on the other side of the diaphragm 85 to the chamber 94.
30 Alternatively, the valve 83 could be a piston air cylinder in which the movable rod 86 is connected to a piston which replaces the diaphragm 85.
An end 86a of the rod 86 may engage an end of a brake actuating rod 87 and an end 86b of the rod 86 may engage an end of a piston rod 88. The brake actuating r i305986 rod 87 is connected to a brake pedal (not shown) through a vacuum servo assistor 89.
The piston rod 88 is connected to a piston 90 of a master brake cylinder 91. The master cylinder 91 is provided with a ~luid reservoir 92 and a fluid outlet 93 which is connected to hydraulic brakes (not shown).
The operation of the embodiment shown in Figure 7 is as follows.
When reverse gear is selected lines 70, 72 and 79 are energised. If the detector 72 is then actuated while reverse gear is selected, then the switch 71 is actuated by air in line 74 which causes line 76 to become energised. This actuates the solenoid 75 which permits 2ressurised air to flow aLong the lines 80 and 82 to the relay switch 77. Air flowing through to the relay switch 77 actuates the switch and energises the line 78. Thus, if the detector is subsequently deactuated the solenoid will still remain actuated until reverse gear is deselected, since the solenoid is connected to the power source via lines 70, 79, 78 and 76.
When the solenoid i5 is actuated pressurised air flows from the line 82 to the line 84 through the relay switch 77 to operate the valve 84. The pressure in line 84 ca~ses expansion of the chamber 94 and compression of the chamber g5 thereby moving the diaphragm 85 to the right.
The rod 86 moves with the diaphragm 85, to which it is connected, towards the piston rod 88. The end 86b of the rod 86 engages the piston rod 88 which causes movement of the piston 90 to actuate the brakes.
When reverse gear is deselected lines 70 and 79 are no longer energised, thereby switching off the pump 79 and deactivating the solenoid 75. The lines 82 and 84 are connected to the exhaust 81, and the diaphragm, by virtue of its resilient nature, returns to its original ~ ~305986 position thereby returning the rod 86 to its original position, This causes piston rod 88 also to move to its original position, thereby deactivating the brakes.
When the valve 83 comprises a piston air cylinder, a spring may be provided to return the piston to the original position. If desired the spring may also be used with the diaphragm 85 to assist return to the original position.
When the brake pedal is applied, the brake actuating rod 87 moves towards and engages the rod 86, thereby moving the rod 86. The rod 86 then moves towards and engages the rod 88 thereby moving the rod 87, and actuating the brakes in the manner described above. When the brake pedal is no longer applied the rods 86, 87 and 15 88 move back to their original positions, thereby deactivating the brakes.
Thus, in the embodiment shown in Figure 7 a mechanical arrangement is provided in the existing brake system for actuating the brakes. The brakes can be 20 actuated either by the brake pedal, or when reverse gear is selected and the detector 73 is actuated.
This invention relates to braking systems and more particularly concerns such systems which are operable to actuate the brakes o~ a vehicle when it is in a reverse condition.
It is known to operate the brakes of a vehicle by means of a system which is operable by a reverse gear actuated switch and a detector at the rear of the vehicle the arrangement being such that the brakes are activated onl~ when the detector contacts an object and the switch is actuated by engagement of reverse gear.
Many prior proposals relate to air-operated bra~ing systems but it is desirable to produce a reverse braking system which can be used with a hydraulic braking system.
There have been some prior prcposals for such systems but none has achieved commercial success.
In particular U.S. Patent No. 2,588,815 (Fasolino) describes various reverse braking systems using electrical switches operated by the vehicle gear lever and a detector at the rear of the vehicle to operate a 20 device which causes operation of the brakes. In one embodiment the device is a power solenoid acting on the brake pedal linkage and in another embodiment is a solenoid valve arranged to apply vacuum from the intake manifold to a pneumatic cylinder connected by a flexible 25 cable to the brake pedal linkage.
U.K. Patent No. 1470129 (Ebbeson et al) describes a similar system actuated by electrical switches and an electromagnetically controlled pneumatic valve. This valve is connected to the vacuum servo of the braking 30 system of the vehicle to control the application of atmospheric pressure to the vacuum chamber of the servo and thereby cause the brakes to be actuated whilst the electrical switch controll~d by the detector is actuated.
The present invention provides an improved reverse ,, ,,," , .. ..
, -` 1305986 actuated auxiliary braking system ~or use with hydraulic vehicle braking systems.
According to the present invention I provide an auxiliary braking system for a vehicle which system comprises means arranged to be actuated by the engagement of reverse gear of the vehicle, said means being connected to operate a valve, a detector connected to operate a valve, said valve or vaLves being arranged in a fluid circuit including a pump for generating pressurised fluid whereby when said valve or valves is or are in an operated condition they permit pressurised fluid to flow and to cause actuation of the braking system.
The pressurised fluid may be a liquid or gas and is preferably air.
Preferably the reverse gear actuated means is a ~ -switch.
The reverse gear actuated switch and the detector may be connected to operate a single valve or two valves arranged in series.
The flow of pressurised fluid may be utilised to pressurise the hydraulic system of the vehicle, either directly or indirectly, or may be utilised to operate mechanical means to actuate the brakes of the vehicle.
In one embodiment of the invention the pressurised fluid is used to operate a hydraulic cylinder which is connected into the hydraulic braking circuit of the t vehicle, either as an auxiliary cylinder, as an existing cylinder in the circuit or as a combination of both with t the cylinders arranged in series or in parallel.
Alte~natively the hydraulic cylinder may be used to operate mechanical means to actuate the brakes; for example it may operate the linkage between the brake pedal and the servo of a servo-assisted braking system.
A simple arrangement is to include the cylinder in a linkage so that when the cylinder is contracted the brake . . .
~30S9186 linkage operates normally but when the cyLinder is expanded it operates the brakes independently of the foot brake pedal.
In a further embodiment the auxiliary braking system further comprises a mechanical arrangement for operating the braking system. The mechanical arrangement may include a rod connected into the existing brake circuit of the vehicle and adapted to actuate the vehicle braking system. The rod may be movable between a first position in which the braking system is not actuated, and a second position in which the braking system is actuated. A
further valve may be provided for moving the rod between the first and second positions.
In this embodiment the vehicle braking system may include a brake actuation rod connected to a brake pedal, and a piston rod for operating a hydraulic brake cylinder; the hydraulic brake cylinder operates the brakes. The rod of the auxiliary braking system can be disposed between the brake actuation rod and the piston rod, so that the brakes can be applied normally by the brake pedal, or through the auxiliary braking system.
This invention is further described with reference to the accompanying drawings, in which:-Figure 1 is a schematic diagram of one form of auxiliary braking system according to the invention;
Figure 2 is a schematic diagram of another form of the invention;
Figure 3 is a schematic diagram of yet another form of the invention;
Figure 4 is a schematic diagram of yet another form of the invention;
Figure 5 is a schematic diagram of yet a further form of the invention;
Figure 6 is a diaqram of a valve suitable for use in the system of Figures 1 to 5; and Figure 7 is a schematic diagram of yet another form , .
~3~sg~6 of the invention.
Figure 1 shows a system in which pressurisedhydraulic fluid is generated by a cylinder and connected into the existing braking circuit by means o~ an additional valve (not shown).
The circuit is based on an air-operated valve 10 which may be of the type shown in Figure 6. Control air is provided to the valve 10 along line 11 which is connected to a pneumatic detector 12 located at the rear of the vehicle. When the valve 10 is not operated the outlet is connected to atmosphere which prevents any accidental build-up of air pressure.
Pressurised air is generated by a pump 13 which is connected in an electrical circuit includinq a gear lever-operated switch 14 and a solenoid valve 15. When reverse gear is engaged pump 13 is energised and provides pressurised air through non-return valve 16 to the air-operated valve 10.
When the pneumatic detector 12 is activated, e.g. by contact with an obstruction, air in line 11 will operate valve 10 to permit pressurised air from the pump 13 to pass into the cylinder 17. This incorporates a piston 18 and piston rod 19 which is mechanically connected to a hydraulic cylinder 20.
The hydraulic cylinder 20 is a conventional type which includes a piston 21 which operates against a return spring 22 and which incorporates a valve element 23 so that when it is moved against the spring pressure it closes off the port 24 connected to fluid reservoir 25 30 and causes pressurised hydraulic fluid to be applied to the line 26 which is connected into the existing hydraulic eluid system of the vehicle by means of a valve (not shown) or by connection into the existing brake master cylinder of the vehicle.
It will be apparent that the pump 13 will generate .,, 1~05986 pressurised air only when operated by the gear lever switch 14 and thus when the vehicle is in a reversing condition. When the vehicle is not in a reversing condition the pump 13 does not operate and the valve 15 remains closed.
The pump 13 may generate noise and to this end it is preferred to locate it near the rear of the vehicle where it will act as a warning device that the vehicle is in a reversing condition.
It has been found that the valve 10 can be operated by a very small change in pressure in the line ll so that a very sensitive system is achieved.
Figure 2 shows a modi~ication of the ~system shown in Figure 1 in which the cylinders 17 and 20 are replaced by a single cylinder 27 which is operated directly by the air pressure in the line 28 from the valve 10.
A further alternative embodiment of the invention is shown schem~tically in Figure 3. The cylinder 30 is air-operated and includes an air-operated piston 31 with 20 a piston rod 32 and return spring 33. The line Z8 is connected in a circuit as shown in Figure 1 but the connection to the braking system of the vehicle is mechanical rather than hydraulic. The piston rod 32 is connected to part of the brake pedal linkage of the vehicle at 34 and the cylinder 30 is connected to the linkage at 35. Thus the linkage can be moved either by pressure of the driver's foot on the pedal 36 or by movement of the piston rod 32 in response to air pressure in the line 28 caused by simultaneous operation of the 30 gear lever switch 14 and the pneumatic detector 12.
The system can be simplified by using a single solenoid valve to replace the valves 10 and 15 in the air circuit of Figure l and an air-operated electrical switch in the electrical circuit. Such an arrangement is shown in Figure 4.
1305~86 The cylinder 40 can be similar to the cylinders 20, 27 or 30 in Figures l to 3 respectively. The pneumatic detector 12 and air line 11 are connected to an air-operated switch 41 which is connected to the solenoid valve 42. The gear lever-operated switch 14 is connected as in Figure l so as to operate pump 13 which supplies pressurised air through non-return valve 16 to the solenoid valve 42. Thus when both switch 14 and switch 41 are operated the solenoid valve will pass pressurised lO air to the cylinder 40 causing actuation of the vehicle brakes as previously described.
An electrical relay 43 may be included so that when switch 41 is operated and then released the solenoid valve 42 will remain operated until the electrical 15 circuit to the relay 43 is broken by moving the gear lever out of reverse and opening switch 14. This causes the brakes of the vehicle to remain actuated after the signal from the pneumatic detector 12 has been interrupted so that the vehicle can be moved only by 20 first disengaging reverse gear after the auxiliary brake system has been operated.
Figure 5 illustrates two further modifications which are within the scope of this invention.
Firstly, an alternative means for holding the brakes 25 on after the signal from the pneumatic detector has been released is the use of an air-operated valve 50. Whilst air pressure remains in the line 28 the valve 42 will remain operated.
Secondly, two hydraulic cylinders are used in 30 tandem. The hydraulic cylinder 20 is part of an auxiliary circuit as shown in Figure 1 but the outlet line 26 for pressurised hydraulic fluid is connected into the fluid circuit of the vehicle braking system by connecting the line 26 to the fluid reservoir inlet 52 of 35 the cylinder 51. By this means when pressurised fluid is ~l3059~l6 generated by the cyLinder 20 in response to the pneumatic detector 12 being operated, it is appLied to the master hydraulic cylinder Sl of the vehicle braking system and pressurises outlet line 53 to operate the brakes of the 5 vehicle.
Normally, the cylinder 51 is operated by means of the foot brake linkage 54 and is not affected by the existence of the auxiliary master cylinder 20 as the line 26 is closed when the cylinder is operated. Topping up Of the system is derived from the fluid reservoir 25.
It may be desirable to provide an air reservoir in the above systems so that a supply of pressurised air is available before the pump has delivered sufficient pressure to operate the system. Generally, however, I
have found that this is not necessary as the volume of the lines can be sufficient for the purpose, particularly where the pump is located at the rear of the vehicle.
The valve lO and the non-return valve 16 serve to retain the pressurised air.
In Figure 6 the valve lO is illustrated. Inlet port 64 is for pressurised air from the pump and inlet port 60 is connected to the line from the pneumatic detector 12.
When the detector is operated pressurised air is applied at inlet 60 causing the valve member 63 to move down against spring 62 causing the port 64 to be closed off from the e~haust to atmosphere (not shown) and to be connected to the outlet port (not shown) to the brake actuating arrangement (e.g. line 28 of Figure l).
A suitable valve is marketed under the name "Boostermite" Type SBV-913 which can be arranged to operate on a differential pressure of one half to three inches of water.
Figure 7 illustrates another embodiment of the invention. In Figure 7 the gear lever switch 14 is 35 connected to a power source (not shown), and also to the ~305~86 pump 13 via electrical line 70. The pump 13 is connected to a switch 71 via an electrical line 72.
The switch 71 is a low sense electrical switch, for example, the switch sold under the name HERGAIR. In an alternative embodiment the switch 71 can be replaced by a Humphrey low sense valve. The switch 71 is pilot operated; a detector 73 is connected to the switch 71 via an air line 74. Air flow through the air line 74 from the detector 73 provides the pilot operation of the switch 71. The detector 73 can include an air bag, and compression of the air bag causes air flow through the air line 74.
The switch 71 is connected to a solenoid 75 via an electrical line 76. A pilot operated relay switch 77 is connected to the solenoid 75 via an electrical line 78 and the line 76. The relay switch 77 i5 also connected to the line 70 via a line 79.
The solenoid 75 is connected to the pump 13 via an air line 80, and is provided with an exhaust 81. The solenoid 75 is connected to the relay valve 77 via an air line 82.
The relay valve 77 is connected to a further valve 83 via an air line 84. The valve 83 is pilot operated by means of the air line 84. The valve 83 shown in Figure 7 is a diaphragm air valve and includes a flexible diaphragm 8S ~hich is connected to a movable rod 86. The valve 83 has a chamber 94 which communicates with the line 84, and a separate chamber 95 which is provided on the other side of the diaphragm 85 to the chamber 94.
30 Alternatively, the valve 83 could be a piston air cylinder in which the movable rod 86 is connected to a piston which replaces the diaphragm 85.
An end 86a of the rod 86 may engage an end of a brake actuating rod 87 and an end 86b of the rod 86 may engage an end of a piston rod 88. The brake actuating r i305986 rod 87 is connected to a brake pedal (not shown) through a vacuum servo assistor 89.
The piston rod 88 is connected to a piston 90 of a master brake cylinder 91. The master cylinder 91 is provided with a ~luid reservoir 92 and a fluid outlet 93 which is connected to hydraulic brakes (not shown).
The operation of the embodiment shown in Figure 7 is as follows.
When reverse gear is selected lines 70, 72 and 79 are energised. If the detector 72 is then actuated while reverse gear is selected, then the switch 71 is actuated by air in line 74 which causes line 76 to become energised. This actuates the solenoid 75 which permits 2ressurised air to flow aLong the lines 80 and 82 to the relay switch 77. Air flowing through to the relay switch 77 actuates the switch and energises the line 78. Thus, if the detector is subsequently deactuated the solenoid will still remain actuated until reverse gear is deselected, since the solenoid is connected to the power source via lines 70, 79, 78 and 76.
When the solenoid i5 is actuated pressurised air flows from the line 82 to the line 84 through the relay switch 77 to operate the valve 84. The pressure in line 84 ca~ses expansion of the chamber 94 and compression of the chamber g5 thereby moving the diaphragm 85 to the right.
The rod 86 moves with the diaphragm 85, to which it is connected, towards the piston rod 88. The end 86b of the rod 86 engages the piston rod 88 which causes movement of the piston 90 to actuate the brakes.
When reverse gear is deselected lines 70 and 79 are no longer energised, thereby switching off the pump 79 and deactivating the solenoid 75. The lines 82 and 84 are connected to the exhaust 81, and the diaphragm, by virtue of its resilient nature, returns to its original ~ ~305986 position thereby returning the rod 86 to its original position, This causes piston rod 88 also to move to its original position, thereby deactivating the brakes.
When the valve 83 comprises a piston air cylinder, a spring may be provided to return the piston to the original position. If desired the spring may also be used with the diaphragm 85 to assist return to the original position.
When the brake pedal is applied, the brake actuating rod 87 moves towards and engages the rod 86, thereby moving the rod 86. The rod 86 then moves towards and engages the rod 88 thereby moving the rod 87, and actuating the brakes in the manner described above. When the brake pedal is no longer applied the rods 86, 87 and 15 88 move back to their original positions, thereby deactivating the brakes.
Thus, in the embodiment shown in Figure 7 a mechanical arrangement is provided in the existing brake system for actuating the brakes. The brakes can be 20 actuated either by the brake pedal, or when reverse gear is selected and the detector 73 is actuated.
Claims (12)
1. An auxiliary braking system for actuating the hydraulic brakes of a vehicle, comprising means arranged to be actuated by the engagement of reverse gear of the vehicle, said means being connected to operate a valve, a detector connected to operate a valve, said valve or valves being arranged in a fluid circuit including an air pump for generating pressurized air, whereby when said valve or valves is or are in an operated condition they permit pressurized fluid to flow and to cause actuation of the hydraulic braking system.
2. An auxiliary braking system according to claim 1 in which said pump is electrically operated and including means for selectively connecting said pump to the battery of said vehicle to energize said pump.
3. An auxiliary braking system according to claim 1 or claim 2 including a pressurized air reservoir connected to store pressurized air from said pump.
4. An auxiliary braking system according to claim 1 or claim 2 in which the reverse gear actuated means is a switch connected to energize said pump when operated by engagement of reverse gear.
5. An auxiliary braking system according to claim 1 in which said hydraulic braking system has a hydraulic cylinder for applying the brakes, and means responsive to the application of pressurized air for actuating said cylinder.
6. An auxiliary braking system according to claim 5 in the pressurized air responsive means is drivably coupled to the brake lever of said hydraulic braking system.
7. A braking device for actuating the hydraulic brakes of a vehicle to arrest reverse motion, said device comprising detecting means for detecting an obstruction of the rear of said vehicle, an air pump, actuating means driven by pressurized air from said pump and controlled by said detecting means for actuating the hydraulic brakes of said vehicle to stop said vehicle when an obstruction is detected.
8. A device as in claim 7 in which said detecting means includes collision detector means mounted at the rear of the vehicle.
9. A device as in claim 7 in which said actuating means includes air cylinder means operated by pressurized air from said pump and connected to an actuation member of said hydraulic brakes.
10. A device as in claim 7 in which said pump is electrically operated, and said detecting means includes means for detecting the reverse condition of said vehicle, and switch means operated when said reverse condition is detected to energize said pump.
11. A device as in claim 10 including a reservoir for storing pressurized gas from said pump, and supplying said gas to said actuating means in response to the detection of an incipient collision.
12. A device as in claim 7 in which said pump is an electric pump, and including means for selectively connecting said pump to the battery of said vehicle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000514791A CA1305986C (en) | 1986-07-28 | 1986-07-28 | Braking system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000514791A CA1305986C (en) | 1986-07-28 | 1986-07-28 | Braking system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1305986C true CA1305986C (en) | 1992-08-04 |
Family
ID=4133639
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000514791A Expired - Fee Related CA1305986C (en) | 1986-07-28 | 1986-07-28 | Braking system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1305986C (en) |
-
1986
- 1986-07-28 CA CA000514791A patent/CA1305986C/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |