HYDRAULIC BRAKE CIRCUIT LOCKING VALVE DEVICE

Abstract: Wheel locking apparatus (10) is provided for immobilizing a vehicle. The locking apparatus (10) includes fluid flow control apparatus (22) having inlet connections and outlet connections (13) whereby it may be interposed in a vehicle's brake fluid line. The fluid flow control apparatus (22) is operable between a blocking position at which flow therethrough is prevented, and an open position at which fluid therethrough is permitted, providing no interference to normal operation of a vehicle. The fluid flow control apparatus (22) is controlled by a key operated actuating means (40) and may be locked to maintain it in a closed position at which the fluid flow control apparatus (22) is closed against flow from the braked wheel's slave cylinder to the master cylinder whereby the wheel is locked against rotation.

Description: HYDRAULICBRAKECIRCUITLOCKINGVALVEDEVICE This invention relates to vehicle brake locking apparatus. This invention has particular application to locking vehicle brakes for the purposes of preventing theft of the vehicle and it will be described in relation to such application hereinafter. However it should be understood that this invention could be used in other applications such as in earth moving equipment for locking the wheels of the vehicle against rotation for operating purposes. Many vehicle anti-theft devices have been provided in the past and include devices for preventing entry to the vehicle, for preventing operation of the engine as well as devices for locking the wheels against rotation. These devices are often electronically controlled and as a result have the potential to be overridden by sophisticated, but readily available, equipment. The mechanical devices which lock the wheels against rotation are mostly in the form of externally applied frames wi ich are chained to a wheel of a vehicle. They are inconvenient and thus unsuited for frequent application. — SUMMARY OF THE INVENTION — The present invention aims to provide wheel locking apparatus which will overcome at least one of the above disadvantages and which will be reliable and efficient in use. In particular as most vehicles are provided with hydraulic or pneumatic wheel braking this invention aims to provide wheel locking apparatus associated with a vehicle's fluid actuated brakes. With the foregoing in view, this invention in one aspect resides broadly in wheel locking apparatus including:- fluid flow control apparatus havi" inlet and outlet connections whereby the fluid flow c crol apparatus may be interposed in a fluid line of a vehicle's brake fluid line, the fluid flow control apparatus being operable between a blocking position at which flow therethrough is prevented, and an open position at which fluid therethrough is permitted, and selectively accessible actuating means for actuating the fluid flow control apparatus. Preferably the selectively accessible actuating means is a key mechanism. The key operated mechanism may be the vehicle's starter key such that it must be removed from the actuating means prior to starting the vehicle. Preferably the key operated mechanism is separate from starter key and is adapted for key insertion and removal at positions which correspond to the blocking position and the open position whereby the keys for both the starter key and the key operated mechanism may be supported on a common key ring. Of course other types of locks may be used such as combination locks. _ The fluid flow control apparatus may be a conventional fluid valve such as a ball, gate or plunger type valve but preferably the fluid flow control apparatus includes a valve member biased to a closed position against flow in one direction only and corresponding to a fluid flow direction from the wheel brake slave cylinder to the brake actuating means or master cylinder. This arrangement provides a fail safe characteristic in which, in the blocking position, fluid may pass from the brake actuating means to the wheel brake slave cylinder and actuate the brakes, locking the wheel in a locked attitude. Without this feature a driver may be unaware that the flow control apparatus is in its blocking attitude as the brake pedal would feel hard and normal, although no braking effort would be transmitted to the brake assembly. Preferably the fluid flow control apparatus includes an upstream valve seat associated with the inlet adapted for connection to the brake actuating means and a valve member biassed for sealing engagement with the valve seat whereby fluid pressure applied to the inlet will lift the valve member from the valve seat thereby permitting fluid to bypass the valve member, while fluid pressure applied to the outlet will force the valve member into sealing engagement with the valve seat thereby preventing fluid flow through the fluid flow control apparatus. This arrangement also enables full pedal pressure to be applied to the brake wheel slave cylinder for locking purposes and for that pressure to be maintained by the locking device. That is the pressure isn't limited to a maximum determined by the biasing means as fluid pressure in the locked line assists engagement of the valve member with the valve seat. The valve body may contain a single outlet and inlet associated with a single valve means such that only one wheel may be locked. Alternatively separate inlet and outlets may be associated with respective valve means in a common or separate valve bodies to suit attachment in any number of braking circuits in a vehicle such as two, three, four or more. In the case of a motor vehicle fitted with ABS braking for example it is preferred that the valve body contain four independent valve means associated with respective pairs of inlets and outlets. Suitably each valve means includes a valve member rotatable by a shaft associated with drive means interconnected to the selectively accessible actuating means whereby a single action of the selectively accessible actuating means will simultaneously operate all valve members. Suitably the valve members are interconnected by a gear train and one or an associated gear of the gear train is provided with a key operated lock which may be rotated through the desired arc for moving the valve members between the blocked position and the open position. It is also preferred that each valve member is a ball valve and that each ball valve is provided with a thrust bearing adapted to oppose the hydraulic forces applied thereto such that the ease of movement of the valve means between the locked position and the open position may be maintained, particularly when the ball valves are subject to high hydraulic pressure. In another aspect this invention resides broadly in a method of immobilising a vehicle comprising:- interposing fluid locking means in a vehicle wheel brake circuit; pressurising the brake circuit, and actuating the fluid locking means so as to maintain fluid braking pressure in the brake circuit. — BRIEF DESCRIPTION OF THE DRAWINGS -- In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a typical embodiment of the present invention and wherein: - FIG. 1 is a perspective view of a preferred embodiment of the invention; FIG. 2 is a typical cross-sectional side view of the embodiment illustrated in FIG. 1; FIG. 3 is a typical cross-sectional plan view of the embodiment illustrated in FIG. 1; FIG. 4 is a plan view of the embodiment of FIG. 1 with the cover removed illustrating the pinion drive mechanism for the four valve assemblies; FIG. 5 is a diagrammatic illustration of a typical installation; FIG. 6 illustrates details of the pinion drive mechanisms; FIG. 7 is a perspective view of a another embodiment of the invention, and FIG. 8 is a perspective view of a another embodiment of the invention. — DESCRIPTION OF THE PREFERRED EMBODIMENT -- The locking apparatus 10 associated with the present invention is in the form of a valve body 11 having four inlet connections 12 and a corresponding number of outlet connections 13 and a key operated rotary actuator 14 mounted centrally on the body 11. The locking apparatus 10 is adapted to be interposed in the four hydraulic lines 15 from a vehicle's an ABS braking device 16 associated with the foot brake actuated master cylinder 17, to the respective hydraulic brake slave cylinders 18 at each wheel 19 of the vehicle as illustrated diagrammatical in Fig. 5. For this purpose the inlet connections 12 and the outlet connections 13 are threaded to receive tapered terminal fittings in conventional manner. As illustrated, the key operated rotary actuator 14 is supported centrally of the valve body 11 with a pinion gear 20 driven thereby and also mounted centrally of the valve body 11 and meshing with a further four gears 21 arranged orbitally about the central pinion gear 20. Each gear is o the same size and configuration such rotation of the pinion gear 20 through a quarter turn by the key operated actuator 14 will cause corresponding rotation of the orbital gears 21, each through a quarter turn. Each orbital gear 21 engages with a ball valve assembly 22 supported in a respective chamber 23 in the valve body 11 associated with the outlet connections 13. As illustrated, each valve assembly 22 includes a ball valve member 24 supported within a chamber 23 and provided with a flow passage 25 therethrough which may be aligned with the respective gallery 26 such that fluid may flow between the inlet connections 12 and the respective outlet connections 13. Each ball valve member 24 is spherical and seats on a complementary shaped valve seat 27 such that when the passage 25 is pivoted by rotation of the orbital gears out of register with the galleries 26, flow from the outlet connection 13 to the inlet connection 12 is prevented. Each ball valve member 24 is biased by compression springs 28, and associated cupped washers 29 which bears against the ball valve member 24, into firm engagement with its valve seat 27 formed at the entrance to the respective galleries 26 to provide a high pressure closure of the galleries 26 with respect to the pressure applied in the brake line 30 downstream of the ball valve member 24. However pressure applied to the opposite faces of the closed ball valve members 24 from the galleries 26 will force them to move away from their seats 27 against the bias of the springs 28. Referring to Figs. 2 and 3 it will be seen that each ball valve member 24 is rotated by a respective orbital gear 21 driven from the key operated pinion gear 20. The orbital gears 21 are located in a recess 31 in the valve body 11 and each supports a spherical thrust bearing or ball 32 adapted to seat under the top cover 33 so as to bear thereagainst and oppose the hydraulic forces applied through the stem 34 which drivingly interconnects the gears 21 to the ball valve members 24 via interlocking spigot and socket connections 38/39 as illustrated in Fig. 6. This ensures ease of movement of the ball valve members 24 between the unlocked position, at which the through passages 25 in the ball valve members 24 align with the respective galleries 26 extending between the inlets 12 and outlets 13, and the locked position, at which the passages 25 do not align with the galleries 26. The stems 34 are sealed by O-ring seals 35. The top cover 33 supports the key operated lock 40 which engages with the pinion gear 16 which is rotatable by the appropriate key 41 to simultaneously contra-rotate the orbital gears 21. The lock 40 utilises a barrel-type key which is relative secure against unauthorized operation and which can be engaged and disengaged in both the locked and unlocked positions at ninety degree intervals. The top cover 33 is also provided with apertured lugs 41 whereby it may be secured to a bulkhead or floor of a vehicle. In use, after a vehicle is parked the brake pedal is depressed sufficiently to operatively engage the brakes in a vehicle holding attitude and the brake locking apparatus is key actuated to the locked position. Subsequent release of pressure on the foot pedal will result in release of the pressure in the brake's fluid supply line at the inlet 12 but maintenance of pressure in the lines 30 and thus locking of the wheels 19. The ball valve member 24 will be forced by downstream fluid pressure into firm engagement with the valve seat 27 assisting in prevention of leakage of hydraulic pressure over a period of time and thus maintenance of the braking effort such that the vehicle brakes may be maintained in a locked attitude for a relatively long period. It is possible, either through lapse of memory or inexperience, for a driver to park a vehicle and rotate the locking apparatus to the locked position without first applying the necessary hydraulic pressure to actuate the b .. In such a situation the vehicle could be driven away w_ - _> .t unlocking the brake locking apparatus whereby hycraulic pressure applied by the operator to the brake lines wil_ force the valve member 24 away from the seat 27 such that fluid may flow about the valve member 24 to the outlet 13 causing the brakes to be applied and locked. In use the car would be brought to a standstill. At that point the operator would be in a safe position aware that the brake locking apparatus was not released prior to commencing the journey and enabling ready rectification of same. The inlet and outlet connectors 12 and 13 are provided with a different size or form threads such that the valve body cannot be inadvertently installed with the inlets and outlets reversed whereby in a circumstance as described above, a driver upon taking off would be unaware that the brakes were isolated from the braking apparatus as the brake pedal would feel hard and normal, although no braking effort would be transmitted to the brake assemblies and the vehicle consequently would be out of control. This would be a very dangerous situation. The locking apparatus 70 illustrated in Fig. 7 is adapted for a conventional braking circuit having independent front and rear circuits. Accordinrly it is provided with two inlet connections 71 at one side a two outlet connections 72 at the opposite side. A simi . - .ock and pinion drive is utilised as for the above <_<- ribed embodiment. The locking apparatus 8 illustrated in Fig. 8 is formed from a selected number of jcking units 81 having drive shafts 82 extending therethrough adapted to interconnect when the units 81 are stacked one beside the other and through bolted together through common bolting apertures 83. The end unit is provided with rotary actuation means such as the lock 84 such that each may be simultaneously operated by a single locking operation. If desired the rotary actuation means could operate through a bevel gear drive to enable the key to extend upwards and the stack of units 81 to extend horizontally. It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is defined in the appended claims.

Claims: — CLAIMS -- 1. Wheel locking apparatus including:- fluid flow control apparatus having inlet and outlet connections whereby said fluid flow control apparatus may be interposed in a vehicle's brake fluid line, said fluid flow control apparatus being operable between a blocking position at which flow therethrough is prevented, and an open position at which fluid therethrough is permitted, and selectively accessible actuating means for actuating said fluid flow control apparatus. 2. Wheel locking apparatus as claimed in claim 1, wherein said selectively accessible actuating means is a key mechanism. 3. Wheel locking apparatus as claimed in claim 2, wherein said key operated mechanism is adapted for key insertion and removal at positions which correspond to said blocking position and said open position. 4. Wheel locking apparatus as claimed in any one of the preceding claims, wherein said fluid flow control apparatus includes a valve member biased to a closed position against flow in one direction only. 5. Wheel locking apparatus as claimed in claim 4, wherein said fluid flow control apparatus includes an upstream valve seat associated with the inlet adapted for connection to the brake actuating means and a valve member biassed for sealing engagement with the valve seat. 6. Wheel locking apparatus as claimed in any one of the preceding claims, wherein said inlet and outlet connections are provided with a different size or form threads for removable connection of the respective brake fluid lines thereto . 7. Wheel locking apparatus as claimed in any one of the preceding claims, wherein said valve body contains a plurality of separate inlet and outlet connections associated 5 with respective valve means in a common or interconnected valve bodies. 8. Wheel locking apparatus as claimed in claim 7, wherein said fluid flow control apparatus includes a valve body assembly having four independent valve means associated 10 with respective pairs of inlets and outlet connections. 9. Wheel locking apparatus as claimed in claim 7, wherein each said valve means includes a valve member rotatable by a shaft associated with drive means interconnected to the selectively accessible actuating means. 15 10. Wheel locking apparatus as claimed in any one of the claims 4 to 9, , wherein each said valve member is a ball valve and that each ball. 11. Wheel locking apparatus as claimed in claim 10, wherein each said valve member is provided with a thrust 20 bearing adapted to oppose the hydraulic forces applied thereto. 12. A method of immobilising a vehicle comprising:- interposing fluid locking means in a vehicle wheel brake circuit; 5 pressurising said brake circuit, and actuating said fluid locking means so as to maintain fluid braking pressure in said brake circuit. 13. A method as claimed in claim 12, wherein said fluid locking means is a wheel locking apparatus as claimed in any 0 one of claims 1 to 11.

Inventors: FING REX JOHN, RAWLINGS DEREK MALCOLM DI, FING, REX, JOHN, RAWLINGS, DEREK, MALCOLM +DI
Applicants: AUSCAN BRAKE LOCK LTD, FING DENIS & LM, FING REX JOHN, AUSCAN BRAKE LOCK LTD., FING, DENIS +LM
Application year: 1993
Main classification: B60R25
IPC codes: B60R25