Patent Publication Number: US-2010127561-A1

Title: Remote trailer brake activator

Description:
FIELD OF THE INVENTION 
     This invention concerns devices for assisting the recovery of stolen or abandoned vehicle trailers. 
     BACKGROUND OF THE INVENTION 
     A typical brake for trucks and trailers uses two pneumatic circuits in its braking system. When braking is being effected air pressure in a compressed air supply line is lowered such that air is drawn from an auxiliary reservoir of compressed air through a central valve which is connected to a spring loaded brake cylinder containing a piston which in turn acts on a brake rod and brake shoe to effect braking. 
     When a trailer is disconnected its brakes are normally actuated. When a trailer is connected to a tractor or truck and connected compressed air passes through the supply line to disengage the brakes. 
     While this is an effective safety development which provides an air brake system which is locked when a trailer is detached, the ability of air brakes to be controlled by connection to a tractors braking system makes security problematic in that, once a trailer is connected to a truck or the like, the braking is deactivated. 
     It is known to monitor the journeys of tractor units and trailers on road systems so that in the event of theft the trailer can be located and recovered before the load is stolen. Trailers have braking systems in which the default position for the brakes is ON and the springs which apply the brakes are resisted by compressed air pressure. The same air pressure is utilised to apply the brakes during driving. While the trailer remains connected to the compressed air supply of the tractor, the trailer remains towable but as soon as the trailer is decoupled the air reservoir discharges and the brake springs ensure the trailer brakes are ON. 
     In US Patent No. 2007/0063582 A1 a security device is accommodated in an accessible box affixed to the trailer, the purpose being to house an exhaust valve which dumps air from the air reservoir when the box is unlocked. Unlocking the box gives access to the handle which opens and closes the valve. 
     SUMMARY OF THE INVENTION 
     This invention provides a device for use with the air braking system of a vehicle of the type in which spring operated brakes are countered by compressed air, comprising a housing containing a pneumatic circuit for inclusion in the air braking system of the vehicle, couplings for connecting the pneumatic circuit to the braking system of the vehicle, valve means in the circuit to admit a compressed air supply in order to both charge the circuit and the braking system and to discharge the circuit and the braking system, phone signal receiving means capable of operating the valve means to both open and close the valve means thereby charging and discharging the air braking system. 
     In a preferred embodiment the circuit has a solenoid operated charging valve and a solenoid operated discharging valve both connected to an air storage tank, both the charging and discharging valves being connectable in parallel to the compressed air supply. The circuit between the discharging valve and the air storage tank has a throttle valve which slows the discharge through the discharge valve in order to secure two stage braking. The circuit between the throttle valve and the air storage tank has a pressure sensing switch which allows the valve means to charge the air storage tank when the tank pressure falls to a predetermined pressure. The phone signal activates a first electronic relay which operates the charge valve and a second electronic relay which operates the discharge valve. 
     The device further comprises a local electronic signal receiving means also capable of operating the valve means. In a preferred embodiment, the local electronic signal receiving means is an infrared sensor and the signal emission is generated by a portable remote control device for use by an authorised operator. 
     A GPS unit capable of emitting and receiving data operates the valve means in addition to the phone signal receiving means. An electronic circuit with a connection for the 24/12 v dc system of the tractor and a dry cell in the housing energizes the solenoid valves. The GPS unit has an aerial, the phone receiving means has an aerial and the infrared sensor has an aerial and both GPS and phone aerials exit the housing through a watertight seal. The housing has a vent for releasing air from the discharging solenoid valve and the vent has a waterproof seal. The vent is a chamber which communicates with the housing and contains multiple metal spheres. These dissipate the force of the released air. The valves, dry cell electronic circuit and pneumatic circuit are fixed to a baseplate mounted on resilient feet attached to the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One embodiment of the invention is now described with reference to the accompanying drawings, in which:— 
         FIG. 1  is a diagrammatic view of part of the trailer to which the device is fixed. 
         FIG. 2  is a sectional view of the housing with the pipework omitted from the interior for clarity. 
         FIG. 3  is a pneumatic diagram of the device. 
         FIG. 4  is a circuit diagram of the device within the housing. 
     
    
    
     DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS 
     In  FIGS. 1 and 2 , the housing  2  is a steel box 400 mm×300 mm×150 mm. Pipe coupling  4  connects the device to the compressed air line  6  charged by the tractor&#39;s compressor (not shown). Coupling  8  connects the device to the spring brake control valve  10  which in turn supplies the brakes  12 . Coupling  14  is connected to the air reservoir  16 . A vent  18  connects the housing interior to the exterior. Vent  18  is a chamber which surrounds an aperture in the housing wall (see  FIG. 2 ). The chamber is filled with small steel balls to prevent ingress of road dirt, snow and insects. It is closed by a flexible flap  20 . The preferred site for the housing is the underside of the trailer above the reserve tank  16 . It helps to select an inconspicuous site and to paint the housing the same colour as the trailer. Brackets  22  with one way nuts secure the housing to the trailer. 
     Baseplate  24  is mounted on rubber bushes  26  and fixed to the housing floor. Lid  28  is hinged to the top of the housing. Outlet  30  has a grommet  32  through which lead  34  enters. Lead  34  ends in a connector  36  for joining with the 12 v dc wiring loom of the trailer. 
     The gland also acts as an exit for a GPS aerial  38  and a longer GMS aerial  39  which wraps around the housing. An antenna  40  for a handheld remote  42  lies inside the housing. 
     Apertures in the baseplate admit two ½″ pipes  44 ,  46  and these supply the pneumatic circuit shown in  FIG. 4 . Air from the tractor vehicle compressor reaches the housing  2  via ½″ pipe  48 . It is admitted to filter  52  before entering the housing  2 . 
     Pneumatic 
     Referring now to  FIG. 3 , the air reservoir  16  both charges and discharges through solenoid valves  54  and  58 . The reservoir connects to atmosphere through the spring brake control valve  10 , and twin solenoid valves  54  and  58 , which is normally closed. The valve discharges into the housing  2  and the housing discharges through the vent  18 . When the twin solenoid valve  58  and valve  54  are in the charge position the air reservoir  16  is able to be charged. 
     Between coupling  8  and solenoid valve  58  there are in series an adjustable valve  60  and a pressure pneumatic switch  62  connected by leg  64 . Bypass  66  is one way excess flow valve, so that when the air chamber  16  empties its diminishing pressure is sensed by the switch  62  and its discharge rate is predetermined by the setting of adjustable valve  60 . In this way an initial fall from about 120 psi to 70 psi occurs in a controlled manner as the reservoir vents to atmosphere. The vehicles brakes are partially applied slowing the vehicle and indicating to the driver that an external signal has applied the brakes. The driver will still have 70 psi to operate the braking system. Valve  60  is adjusted and set to air flow rate at the time of installation to the individual vehicle by insertion of a tool in aperture  68  in the housing. Second leg  68  and one way valve  70  allow air escape at a different lower pressure. This route bypasses the activation procedure and permits the spring brake control valve to act as it normally would. 
     Electrical 
     Turning to  FIG. 4 , that figure illustrates the state of the circuit  100  when the trailer is disconnected from the trailer power supply  34 . 
     A single-pole double-throw relay A has a solenoid  101 , a pole  104  which is associated with normally-closed contact  102  and with normally-open contact  103 . The solenoid  101  of relay A is connected across the tractor power supply  34 . The pole  104  is connected at  128  to pin  10  of the GPS unit  127 , and to relay solenoids  109  and  113  as described below. The normally-closed contact  102  of relay A is connected to relay D as is described below. The normally-open contact  103  of relay A is connected to the positive line of the tractor power supply  34 . Contact Pin  4  of the GPS unit  127  is connected at  128  to pin  10  of the GPS unit. 
     A single-pole single-throw relay B has a solenoid  109 , a pole  112  and a normally-open contact  111  which in turn is connected to one contact of a solenoid valve  118 , which is also labelled as B 2  in the drawings. The other contact of the solenoid valve  118  is connected to ground. The pole  112  of the relay B is connected at  128  to the pin  10  of the GPS unit  127 . The solenoid  109  of relay B is connected at  128  to pin  10  of the GPS unit and at  134  to pin  1  of the GPS unit. 
     A single-pole single-throw relay C has a solenoid  113 , a pole  116  and a normally-open contact  114  which in turn is connected to one contact of a solenoid valve  119 , which is also labelled as B 1  in the drawings. The other contact of the solenoid valve  119  is connected to ground. The pole  116  of the relay C is connected at  128  to pin  10  of the GPS unit  127 . The solenoid  113  of the relay C is connected at  128  to pin  10  of the GPS unit and at  136  to pin  2  of the GPS unit  127 . 
     A single-pole double-throw relay D has a solenoid  122 , a double-throw pole  126 , a normally-closed contact  124  and a normally-open contact  123 . The pole  126  of the relay D is connected to the positive terminal of the battery  12 . The normally-open contact  123  is connected to the cathode  131  of diode  129 . The normally-closed contact  124  is connected to the normally-closed contact  102  of the relay A. 
     The pressure switch  121 , which is also labelled as E in the drawings, has one terminal which is connected to a terminal of the solenoid valve  117 , which is also labelled as C 1  in the drawings, while another terminal of the pressure switch E is connected to one terminal of pressure switch S. The second terminal of pressure switch S is connected at  128  to the pin  10  of the GPS unit  127 . 
     Pin Arrangement of GPS Unit (G) 
     
       
         
           
               
               
               
               
             
               
                   
               
             
            
               
                 Pin 1. 
                 UNLOCK (Pulse) 
                 Pin 2. 
                 LOCK (Pulse) 
               
               
                 Pin 3. 
                 Handheld Remote Antenna 
                 Pin 4. 
                 IGNITION Input 
               
               
                 Pin 9. 
                 Ground 
                 Pin 10. 
                 MAIN POWER 
               
               
                   
                   
                   
                 (+12 VDC) 
               
               
                   
               
            
           
         
       
     
     Operation 
     When the tractor power supply  34  is connected to the circuit  100 , relay A is in the energized state. When relay A is energized, its pole  104  is in contact with normally-open contact  103 . The GPS unit  127  is thus energized from the tractor power supply  34  through the normally-open contact  107  and the pole  108 . An “ignition on” signal is also supplied at  133  to pin  4  of the GPS unit. The solenoid  109  of relay B and the solenoid  113  of relay C can be energized by tractor power through normally-open contact  103  and pole  104  if an unlock or lock signal is received by the GPS unit. 
     The solenoid  122  of relay D is also energized from the tractor power supply  34  and connects the internal battery  12  to the tractor power supply  34 . 
     When the tractor ignition power is turned off, relay D de-energizes and pole  126  is in contact with the normally-closed contact  124  and connects the internal battery  12  to the normally-closed contact  102  of relay A. The coil  101  of relay A is de-energized. Pole  104  of relay A then moves to the normally-closed contact  102 . Pole  104  of relay A provides power to pin  10  of the GPS unit at  128 . When pole  104  is on the normally-closed contact  102 , the solenoid  109  of relay B and the solenoid  113  of relay C can be energized by the internal battery  12  through normally-closed contact  102  and pole  104  if an unlock or lock signal is received by the GPS unit. 
     If a lock signal is received by the GPS unit  127  the solenoid  113  of relay C energizes resulting in closing the normally-open contact  114  and the energization of solenoid valve  119 , also shown as coil B 1  in the drawings. This will result in the valve  119  venting air from the tank  16  through a fixed orifice in the V 60  valve. The pressure in the tank  16  then drops to the predetermined value which has been set by the pressure switch  121 , which is also shown as E in the drawings. When this value is reached solenoid valve  117 , shown as C 1  in the drawings, will de-energize which will vent the spring brake valve  10 . 
     The result is that the system is exhausted of air and the brakes are on. 
     When the apparatus  100  is subsequently re-connected to the tractor power supply  34 , and supplied with an “unlock” command from the handheld remote  42 , the relay solenoid  109  of relay B is energized, the contact  111  closes and the solenoid valve  118 , which is also shown as B 2  in the drawings, energizes. The energization of solenoid valve  111  allows air from the tractor compressor to charge the tank  16 . When air pressure reaches a pre-determined value, switch  121 , which is also shown as E in the drawings, will energize the solenoid valve  117 , which is also shown as C 1  in the drawings, allowing flow of air through the spring brake valve  10  to charge the brakes. 
     The operation of the second pressure switch S is as follows. When the tractor hand brake is applied, air to the unit  100  is removed. This drop in pressure is detected by pressure switch S  120  and causes coil  117 , also shown as C 1  in the drawings, to de-energize. This will vent the spring brake valve causing the brakes to be applied. When the tractor hand brake is disengaged air is restored to the unit  100 . The application of air is detected by pressure switch S  120  and causes coil  117  to energize. Tractor air is now able to charge the spring brake valve and the brakes relaxed. 
     
       
         
           
               
             
               
                   
               
               
                 20090604 component list 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 100. 
                 electric circuit 
               
               
                 101. 
                 solenoid of relay A 
               
               
                 102. 
                 contact of relay A 
               
               
                 103. 
                 contact of relay A 
               
               
                 104. 
                 pole of relay A 
               
               
                 106. 
                 contact of relay A 
               
               
                 107. 
                 contact of relay A 
               
               
                 108. 
                 pole of relay A 
               
               
                 109. 
                 solenoid of relay B 
               
               
                 111. 
                 contact of relay B 
               
               
                 112. 
                 pole of relay B 
               
               
                 113. 
                 solenoid of relay C 
               
               
                 114. 
                 contact of relay C 
               
               
                 116. 
                 pole of relay C 
               
               
                 117. 
                 solenoid valve C1 
               
               
                 118. 
                 solenoid valve B2 
               
               
                 119. 
                 solenoid valve B1 
               
               
                 120. 
                 pressure switch S 
               
               
                 121. 
                 pressure switch E 
               
               
                 122. 
                 solenoid of relay D 
               
               
                 123. 
                 contact of relay D 
               
               
                 124. 
                 contact of relay D 
               
               
                 126. 
                 pole of relay D 
               
               
                 127. 
                 GPS unit 
               
               
                 128. 
                 pin 10 of GPS unit 127 
               
               
                 129. 
                 diode 
               
               
                 131. 
                 cathode of diode 
               
               
                 132. 
                 anode of diode 
               
               
                 133. 
                 pin 4 of GPS unit 127 
               
               
                 134. 
                 pin 1 of GPS unit 127 
               
               
                 136. 
                 pin 2 of GPS unit 127 
               
               
                   
               
            
           
         
       
     
     Sequence of Drivers Operation 
     The driver couples the trailer to the truck by connecting a flexible air hose between the compressed air system of the truck to the compressed air system of the brakes. The truck&#39;s 12 v dc system is switched on by the ignition switch. The engine starts and the truck compressor charges the air reservoir to the brakes. The brakes of the truck are OFF and the truck and trailer commence their journey. 
     If the driver pulls in for a temporary stop switching off the ignition also switches off the 12 v dc. The truck unit activates the air reservoir exhausts and the brakes are ON. 
     If the truck or trailer are stolen or leaves the designated route, which can be divided into stages for monitoring purposes, the trucking overseer obtains a GPS fix and sends a telephone command to the GPS which triggers the valve system into active mode. This applies the brakes. If the vehicle or trailer are parked, the vehicle is immobilized and the police are advised of its location If the vehicle is mobile, the brakes come ON and the truck slows noticeably giving the driver time to change lanes and park off the road. By that time the air reservoir is discharging and the truck is immobilized. 
     When the owner or the police has secured the vehicle the unit can be restored to a mobile state by way of telephone command to deactivate and the GPS triggers the valves will close to allow air into the reservoir, returning the braking system to normal state. 
     We have found the advantages of the above embodiment to be: 
     1. Manual operation of the air valve is replaced by signal operation. 
     2. The system responds to both signals from telephone or GPS systems and local signals provided by a driver. 
     3. Two stage pressure loss gives the driver time to pull off the road and bring the tractor and trailer to a safe stop using the lowered pressure to apply the brakes. 
     It is to be understood that the word “comprising” as used throughout the specification is to be interpreted in its inclusive form, ie. use of the word “comprising” does not exclude the addition of other elements. 
     It is to be understood that various modifications of and/or additions to the invention can be made without departing from the basic nature of the invention. These modifications and/or additions are therefore considered to fall within the scope of the invention.