Abstract:
This invention relates to a demountable vehicle body system, in which a variety of different body types can be mounted and demounted from a vehicle chassis or trailer to enable a single vehicle chassis or trailer to be utilised for a variety of different purposes. In particular, the present invention relates to a demountable vehicle body system for motor vehicles and trailers which provides for a convenient and cost effective use of a variety of vehicle body types. Advantageously, the present invention provides a demountable vehicle body system that is capable of safely mounting or demounting a wide variety of vehicle body types, including fully-loaded heavy bodies, in a smooth and efficient manner. The vehicle body system described herein can be mounted or demounted in a matter of minutes by a single operator.

Description:
RELATED APPLICATION INFORMATION 
       [0001]    This patent claims priority from International PCT Patent Application No. PCT/GB2009/001300, filed on May 21, 2009 entitled, “DEMOUNTABLE VEHICLE BODY SYSTEM”, which claims priority to GB Application No. GB0809195.1, filed on May 21, 2008 entitled “DEMOUNTABLE VEHICLE BODY SYSTEM”. 
     
    
     NOTICE OF COPYRIGHTS AND TRADE DRESS 
       [0002]    A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever. 
       BACKGROUND 
     Field 
       [0003]    The present invention relates to a demountable vehicle body system, in which a variety of different body types can be mounted and demounted from a vehicle chassis or trailer to enable a single vehicle chassis or trailer to be utilised for a variety of different purposes. 
         [0004]    At the present time commercial vehicles are usually manufactured having a standard front cab and a variety of standard rear cab types, including, for example, a box cab, a Luton cab, a flat deck or a tipper. In addition, a plurality of specialised rear cabs can be supplied to order and these might include refrigerated rear cabs, minibuses, horse boxes, cement mixers, breakdown lorries, street light lifts, bowsers and the like for liquid or bulk material or live stock carrying cabs. Generally, as a consequence, as the individual body type is normally provided as an integral part of the rear portion of the vehicle, each vehicle is generally suitable only for the purpose for which it was designed, therefore, the user of a variety of different types of vehicle would require to have a number of each vehicle types for this purpose, even though it is unlikely that all of the vehicles will need to be used at all the times and such an arrangement can involve a considerable capital outlay for a fleet user. 
         [0005]    Also, over the past few decades many parts of the world have experienced a gradual reduction in working hours and a consequent increase in leisure time. Many of these resulting leisure and cultural activities take place outdoors and at selected venues where spectator seating, toilet and catering facilities are not organised on a permanent basis. Increasingly, there is the need for facilities such as catering stands, mobile grandstands, mobile toilets etc. and there are systems available in the marketplace in which rear cabs are detachable from the vehicle by means of legs which are extendable and which raise the rear cab from the vehicle, which is then subsequently driven away. However, these tend to be time consuming to unload and do not allow the rear cab to be dropped to ground level. 
         [0006]    A further example of a prior art arrangement is known in GB 2 240 751, which was made by the inventor of the present application. Basically, this system comprises a support frame attachable to the vehicle and a demountable body frame on which various vehicle bodies can be secured. The vehicle body frame can be removed from the vehicle by means of a cable winch mechanism driving an endless cable mechanism, the endless cable mechanism being connectable to the demountable body via a coupling member. Whilst this invention was commercially successful, the disadvantage of this approach was that the inertia of “heavier” body types tended to cause the vehicle body to jerk and move irregularly during mounting or demounting operations. 
         [0007]    It is therefore the object of the present invention to provide a demountable vehicle body system for motor vehicles and trailers which overcomes the disadvantages of prior art arrangements and provides for a convenient and cost effective use of a variety of vehicle body types. In use, it is a further object of the present invention to provide a demountable vehicle body system that is capable of safely mounting or demounting a wide variety of vehicle body types, including fully-loaded heavy bodies, in a much smoother and efficient manner. The vehicle body system described herein can be mounted or demounted in a matter of minutes by a single operator. 
         [0008]    According to the present invention there is provided a vehicle body exchange system for vehicles or trailers, comprising:
       a support frame attachable or integrally mounted with a vehicle chassis or trailer unit, said support frame capable of receiving a vehicle body;   a first winch means connected to a coupling member for connection to a vehicle body to enable said vehicle body to be lifted from the ground or lowered to the ground during a mounting or demounting operation;   a second winch means connected to a coupling member for connection to a vehicle body to enable said vehicle body to be lifted from the ground or lowered to the ground during said mounting or demounting operation; and   means for independently controlling the rotational speed of said first and second winch means during said mounting or demounting operation to enable a smooth displacement of said vehicle body.       
 
         [0013]    Preferably, the chassis frame comprises at least two guide rails or channel sections for receiving and guiding corresponding channels or guide rails on the demountable body frame. The chassis frame may also include a tilt frame which pivots in the direction of motion of the body frame relative to the chassis frame. In use, the coupling member for connection to a vehicle body may be provided as a connector plate. 
         [0014]    Towards the rear of the chassis frame, a rear cable guide roller and an auxiliary guide roller can be provided which, in use, guide the cables when performing said mounting or demounting operation. Guide rails and corresponding guide rollers may, preferably, enable the body frame to connect with the chassis frame during mounting or demounting operations. A further set of guide rails may be provided along the chassis frame to ensure that the body frame is pulled on squarely and securely. 
         [0015]    Further preferably, a lock release handle is mounted on the chassis frame which is engaged when the body frame is mounted securely on the chassis frame. 
         [0016]    Preferably, the vehicle body is secured on a body frame. The body frame may consist of two L-shaped guide rails, which, in a mounted condition, sit on the guide rails of the chassis frame. Towards the rear of the body frame, either fixed rolled wheels or additional torsion wheels can be inserted into the body frame. The body frame may also have means for receiving the connector plate which is connected to the first and second winch means. In use, the connector plate is secured via locking bar. Preferably, the connector plate can be quickly ejected via a spring-loaded release mechanism which is activated by using a connector plate ejector. 
         [0017]    Further preferably, the first winch means comprises a first motor which turns, via a gear mechanism, a single cable drum that is mainly used to pull the vehicle body off the vehicle. The first motor may be an induction motor capable of being pulled out when no power is applied. 
         [0018]    Preferably, the second winch means comprises a second motor which turns, via a gear mechanism, a twin cable drum that is mainly used to pull the vehicle body on to the vehicle. The second motor may be a winch motor which cannot be pulled out when no power is applied. 
         [0019]    In use, the means for independently controlling the rotational speed of said first and second winch can be provided using a microcontroller or microprocessor. A plurality of sensors detect the relative position of the vehicle body relative to the chassis frame and these are inputted to the microcontroller or microprocessor. In use, these comprise a first sensor, which can be a microswitch, and its function is to detect when the body frame is locked in position on the chassis frame; a second sensor, which can be a microswitch, which senses when the body frame is in an unlocked position; a third sensor, which can be a capacitive sensor, that is used to notify when the body frame is located on the chassis frame; and a fourth sensor, which can be a capacitive sensor, which senses when the body frame is at the rear of the cable guide roller. 
         [0020]    Further preferably, any number of vehicle body types can be utilised, for example, a box cab, a Luton cab, a flat deck, tipper, refrigerated rear cab, minibus, horse box, cement mixer, breakdown lorry, street light lift, bowsers and the like for liquid or bulk material, live stock carrying cabs, catering stands, mobile grandstands or mobile toilets. 
         [0021]    Also according to the present invention there is provided a computer program product for controlling the mounting or demounting of a vehicle body relative to a support frame which is attachable or integrally mounted with a vehicle chassis or trailer unit, said support frame having first and second winch means mounted thereon and connected to a coupling member for connection to the vehicle body to enable said vehicle body to be lifted from the ground or lowered to the ground during a mounting or demounting operation, comprising:
       computer program means for monitoring the position of said vehicle body relative to said support frame; and   computer program means for independently controlling the rotational speed of said first and second winch means to enable a smooth displacement of said vehicle body.       
 
         [0024]    It is believed that a demountable vehicle body system for motor vehicles and trailers in accordance with the present invention at least addresses the problems outlined above. In particular, the advantages of the present invention are that demountable vehicle body system for motor vehicles and trailers is provided which provides for a convenient and cost effective use of a variety of vehicle body types. Advantageously, the present invention provides a demountable vehicle body system that is capable of safely mounting or demounting a wide variety of vehicle body types, including fully-loaded heavy bodies, in a much smoother and efficient manner. Further advantageously, the vehicle body system described herein can be mounted or demounted in a matter of minutes by a single operator. 
         [0025]    It will be obvious to those skilled in the art that variations of the present invention are possible and it is intended that the present invention may be used other than as specifically described herein. 
         [0026]    A specific non-limiting embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  shows a plan view from above of the chassis frame, which, in use, is attachable or integrally formed with a vehicle chassis or mounted on a trailer in accordance with the present invention; 
           [0028]      FIG. 2  is a perspective view from the side of a vehicle body frame, which, in use, is capable of receiving any number of vehicle body types in accordance with the present invention; 
           [0029]      FIG. 3  shows detail of the winch cable mechanism in accordance with the present invention; 
           [0030]      FIGS. 4A to 4C  show schematically how a connector plate, which is used to connect to the vehicle body frame, can be raised and lowered using the winch cable mechanism of  FIG. 3 ; 
           [0031]      FIGS. 5A and 5B  show perspective views from below and above, respectively, of the connector plate which is used to connect to the vehicle body frame; 
           [0032]      FIG. 6  shows a perspective view from the side of the tilt frame, mounted at the rear of the chassis frame, which is used to provide a smooth operation when mounting or demounting a vehicle body frame; 
           [0033]      FIG. 7  shows a schematic view of the position of various sensors which are used to provide control signals to the winch cable mechanism when mounting and demounting; 
           [0034]      FIGS. 8A to 8G  show schematic views of the how the present invention is utilised to demount a vehicle body frame; 
           [0035]      FIGS. 9A to 9I  show schematic views of the how the present invention is utilised to mount a vehicle body frame; 
           [0036]      FIGS. 10A to 10C  show how the present invention can be implemented as part of a trailer system; 
           [0037]      FIG. 11  is a perspective view from the rear which shows further detail of the tilt frame, mounted at the rear of the chassis frame, and the rear cable guide roller which is used to guide the cables when performing a mounting or demounting operation; and 
           [0038]      FIG. 12  is a perspective view from the front of one of the spring retaining clips which are used to retain the cables over the rear cable guide roller, in use. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    Referring now to the drawings, the implementation of the present invention is shown in  FIGS. 1 to 10 . Referring firstly to  FIG. 1 , which shows detail of the chassis frame  10  which, in use, is intended to be attachable or integrally formed with a vehicle chassis (not shown) or mounted on a trailer (not shown). The chassis frame  10  comprises at least two guide rails  12  or channel sections for receiving and guiding corresponding channels or guide rails  42  on the demountable body frame  40 , as shown in  FIG. 2 . The guide rails  12  are strengthened by a number of cross-pieces  14 . The chassis frame  10  is secured to the vehicle chassis (not shown) or mounted on a trailer (not shown) via a plurality of mounting means  16 . At the front end of the chassis frame  10  (the cab end), a cable winch mechanism or winch box  18  is provided for mounting and demounting the body frame  40 , and further detail is provided in  FIGS. 3 and 4 . For clarity purposes, the cables are not shown in  FIG. 1 . 
         [0040]    Towards the rear of the chassis frame  10 , a rear cable guide roller  20  is provided which is used to guide the cables when performing a mounting or demounting operation. Guide rails  22  and corresponding guide rollers  24  enable the body frame  40  to connect with the chassis frame  10  during mounting or demounting operations. A further set of guide rails  26  is provided along the chassis frame  10  to ensure that the body frame  40  is pulled on squarely and securely.  FIG. 1  also shows detail of the pivotable tilt frame  28  which assists with the smooth operation of the mounting and demounting of vehicle bodies. The tilt frame  28  is pivotable or tiltable along the line AA′ in  FIG. 1 . 
         [0041]      FIG. 1  also shows is a lock release handle  30  which is engaged when the body frame  40  is mounted securely on the chassis frame  10 , and which causes a lock action through points  32 . In this way, the body frame  40  can be rapidly secured for transport. 
         [0042]      FIG. 2  shows detail of the vehicle body frame  40 , on which, in use, various types of vehicle bodies (not shown) can be mounted. The body frame  40  consists of two L-shaped guide rails  42  which, in a loaded condition, sit on the guide rails  12  of the chassis frame  10 . Again, cross-members  44  provide structural support. Towards the rear of the body frame are either fixed rolled wheels  46 , or if heavier bodies are envisaged, then additional torsion wheels  48  can be inserted into the body frame  40 . The body frame  40  also has means for receiving a connector plate  50  which is connected to the cable winch mechanism  18  on the chassis frame  10  via cables (not shown). In use, the connector plate  50  is secured via locking bar  52 . The connector plate can be quickly ejected via a spring-loaded release mechanism which is activated by using the connector plate ejector  54 . Further detail of the connector plate and its method of operation will be discussed later in relation to  FIGS. 8A to 8G  and  9 A to  9 I. Also mounted on the body frame  40  are locking pins  56  which mount with the apertures  32  on the chassis frame  10 , as described above. 
         [0043]      FIG. 3  shows detail of the winch box  18  that is used to pull the vehicle body  40  on and off the vehicle. Motor  1  turns, via a gear mechanism, a single cable drum  60  that is mainly used to pull the vehicle body  40  off the vehicle. It is an induction motor capable of being pulled out when no power is applied. Motor  2  turns, via a gear mechanism, a twin cable drum  58  that is mainly used to pull the vehicle body on to the vehicle. This is a winch motor which cannot be pulled out when no power is applied. Obviously this is from a safety point of view should power be lost during a winching mechanism. 
         [0044]    The key to smooth operating of the present invention is the difference in performance and configuration of the motors  1  and  2 . As mentioned, motor  1  has a single cable drum  60  that the cable  70  is fed down the full length of the vehicle to the rear, round the pulley  20  and back to fix to the connector plate  50 . It is capable of being pulled out when no power is applied. Some force is required to pull out the cable, in use, maintaining tension on the cable. 
         [0045]    Motor  2  is the main lifting motor and has two cables  68  on its drum  58 . It is attached directly to the connector plate  50 . This is a winch motor which can feed out or in under power. When no power is applied the drum  58  is locked, this feature is critical to the safe operation of the system. When feeding out cable  68 , the drum  58  cannot be accelerated by applying tension to the cable  68 . 
         [0046]      FIGS. 4A to 4C  show the principle of operation of the invention without any detail of the chassis frame  10  or body frame  40  shown in these drawings, as this aids the explanation of the invention. Mounted on the chassis frame  10  (not shown), inside the winch box  18  (not shown), are the ON and OFF drums  58  and  60 , respectively, which connect with the connector plate  50  via ON and OFF cables  68  and  70 , respectively. As noted above, in use, the connector plate  50  would be secured in the body frame  40  (not shown). Towards the rear of the chassis frame  10  is the cable guide roller  20  and an auxiliary guide roller  64 .  FIGS. 4A to 4C  show the demount operation as follows: 
         [0047]    In  FIG. 4A , the ON and OFF drums  58  and  60  are driven, via motors  2  and  1 , respectively, and the ON and OFF drums  58  and  60  rotate clockwise. The OFF drum  60  takes up OFF cable  70  drawing the connector plate  50  (which is connected to the body frame  40 ) to the rear. The ON drum  58  pays out cable  68  subject to dynamic braking or under torque. 
         [0048]    As the body frame  40  is drawn to the rear of the chassis frame  10 , the tilt frame  28  (not shown) begins to tilt, the torque and downward force of the OFF cable  70  pulls (as the centre of gravity of the body is being transferred), the rear of the tilt frame  28  in a downward motion, thereby sensing and controlling the angle and speed of tilt of the moving body prior to the front of the body frame and body, reaching the top dead centre of the tilt frame rear rollers  74  (as shown in  FIG. 6 ). 
         [0049]    At this point, as shown in  FIG. 4B , the body frame  40  reaches the extreme rear of the cable guide roller  20  of the tilt frame  28  (beyond top dead centre). A sensor gives indication, or drum revolution counter, to power motor  2  and the ON drum cables  68  now take the mass and continues to rotate in a clockwise direction lowering the load to the ground. 
         [0050]    At the same time, the OFF drum  60  is disengaged and the continual downward motion of the body frame  40  causes the OFF drum  60  to unwind allowing the OFF cable  70  to be drawn by the load to the ground, as shown in  FIG. 4C . There will be minimum slack cable in the OFF drum  60 . 
         [0051]      FIGS. 5A and 5B  show further detail of the connector plate  50  which is used to couple the ON and OFF cables  68  and  70  to the body frame  40 . As shown in  FIG. 5A , which corresponds to  FIG. 3A  which shows the connector plate  50  being withdrawn across the chassis frame  10 .  FIG. 5B  shows the position of the ON and OFF cables  68  and  70  on the connector plate  50  when the body  40  is lowered over the rear roller  20  and as it reaches the ground. It is the interaction of the cables  68  and  70 , via the pivots  72 , which assists in the smooth operation of the invention. 
         [0052]      FIG. 6  shows further detail of the tilt frame  28  mounted at the rear of the chassis frame  10 . As can be clearly seen, the tilt frame  28  is able to pivot or tilt along pivot  74 . At the end of the tilt frame  28 , the guide rails  22  and corresponding guide rollers  24  enable the body frame  40  to connect with the chassis frame  10  during mounting or demounting operations.  FIG. 6  is also useful in showing how the ON and OFF cables  68  and  70  are situated above and below the roller  20 , respectively, when the connector plate  50  is extended. 
         [0053]      FIG. 7  shows a schematic view of the location of the sensors used with the present invention. In particular, Sensor A is a microswitch and its function is to detect when the body frame  40  is locked in position on the chassis frame  10 . Sensor B is a also microswitch which senses when the body frame  40  is in an unlocked position. Sensor C is a capacitive sensor that is used to notify when the body frame  40  is located on the chassis frame  10 . Sensor D is again a capacitive sensor which senses when the body frame  40  is at the rear of the cable guide roller  20 . The key to the smooth operation of the present invention is the accurate measurement of the body frame  40  relative to the chassis frame  10 , particularly via sensors C and D. As described above in  FIGS. 4A to 4C , the switching points of motors  1  and  2  is set by Sensors C and D. Due to the wrap of the cables  68  and  70  at the rear of the chassis frame these switching points are critical. For example, during a mounting operation, sensor D detects the body as the body approaches the underside of the cable guide roller  20 . At this point, the OFF cable  70  attached to motor  1  is at its minimum length. From this point, the OFF cable  70  attached to motor  1  must be pulled out by motor  2 . 
         [0054]      FIGS. 8A to 8G  show schematically the unloading (or demounting) sequence performed by the present invention. In  FIG. 8A , the body frame  40  (not shown) having vehicle body  100  mounted thereon, is unlocked by releasing locks using manual handle  30  (not shown). The body  100  moves back on chassis frame away from locks. 
         [0055]    As shown in Table 1, motor  1  speed exceeds motor  2  speed. This forces the speed of motor  1  to be controlled by the maximum feed rate of motor  1 . The cables  68  and  70  are always kept in tension with no slack cable allowed to develop. The movement of the body  100  is controlled by the tension in the cables  68  and  70 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Active Sensors:  
                 Motors:  
               
               
                   
                   
               
             
             
               
                   
                 A. Body in lock position  
                 1. 90% power feeding in  
               
               
                   
                 B. Locks disengaged  
                 2. 100% power feeding out 
               
               
                   
                 C. Body on vehicle 
               
               
                   
                   
               
             
          
         
       
     
         [0056]    As shown in  FIG. 8B , the body  100  continues to move towards the rear of the vehicle. As shown in Table 2, motor  1  speed continues to exceed motor  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 C. Body on vehicle 
                 1. 90% power feeding in 
               
               
                   
                   
                 2. 100% power feeding out 
               
               
                   
                   
               
             
          
         
       
     
         [0057]    As shown in  FIG. 8C , the body  100  tilts; the speed of which is controlled by motor  2 . As the body  100  tilts the amount of tilt of the body  100  is controlled by the feed rate of motor  2  and the tension applied to the OFF cable  70  by motor  1 . As shown in Table 3, motor  1  speed continues to exceed motor  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 C. Body on vehicle 
                 1. 90% power feeding in 
               
               
                   
                   
                 2. 100% power feeding out 
               
               
                   
                   
               
             
          
         
       
     
         [0058]    As the body  100  clears sensor C, at  FIG. 8D , motor  1  is reversed. The speed of motor  1  is set to be a fraction below motor  2 &#39;s payout. This prevents slack cables  68  and  70  as they are pulled around the rear roller  20  (not shown). At this point, gravity is used to carry the body  100  off the vehicle. Table 4 shows the feed-rate of motors  1  and  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 1. 75% power feeding out 
               
               
                   
                   
                 2. 100% power feeding out 
               
               
                   
                   
               
             
          
         
       
     
         [0059]    In  FIG. 8E , the body  100  is lowered to ground. As the body  100  lowers under gravity, motor  2  accelerates above motor  1 &#39;s speed taking up any slack cables  68  and  70  in the system. Once the OFF cable  70  attached to motor  1  becomes tight, motor  1  acts as a brake slowing the body  100  decent. The speed of decent will be a function of the body  100  loading, motor  1  resistance and motor  2  feed-out rate. Table 5 shows the feed-rate of motors  1  and  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 1. 75% power feeding out 
               
               
                   
                   
                 2. 100% power feeding out 
               
               
                   
                   
               
             
          
         
       
     
         [0060]    At  FIG. 8F , the connector plate  50  (not shown) is ejected manually from vehicle by the operator. Both motors  1  and  2  are deactivated, as shown in Table 6. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 None 
               
               
                   
                   
               
             
          
         
       
     
         [0061]    At  FIG. 8G , the slack cables  68  and  70  are recovered and connector plate  50  stored. The vehicle can then be simply driven away. Table 7 shows the feed-rate of motors  1  and  2  at this point. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 1. 80% power feeding in 
               
               
                   
                   
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0062]    Correspondingly  FIGS. 9A to 9I  show the reverse operation for loading or mounting the body  100  on to a vehicle. In  FIG. 9A , the vehicle approaches the body  100 . Both motors  1  and  2  are deactivated, as shown in Table 8. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 None 
               
               
                   
                   
               
             
          
         
       
     
         [0063]    At  FIG. 9B , the operator then presses the feed button (not shown) on rear of vehicle, which feeds out cables  68  and  70 . Table 9 shows the feed-rate of motors  1  and  2  at this point. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 1. 80% power feeding out 
               
               
                   
                   
                 2. 100% power feeding out 
               
               
                   
                   
               
             
          
         
       
     
         [0064]      FIG. 9C  shows the body  100  being is pulled towards vehicle, aligning itself. Motor  1  speed is set to exceed motor  2  speed to take up any possible slack in cables  68  and  70 . Motor  1  is not capable of lifting the body  100  at its full speed and as it comes under load its speed slows down matching motor  2  speed. As motor  2  has a fixed feed rate and its power at this speed exceeds that of motor  1  the cables  68  and  70  are kept tight while motor  2  carries out the main lifting and pulling of the body  100  with motor  1  contributing. Table 10 shows the feed-rate of motors  1  and  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 10 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 None 
                 1. 90% power feeding in 
               
               
                   
                   
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0065]    When the body triggers Sensor D, at  FIG. 9D , motor  1  is disconnected. The OFF cable  70  attached to motor  1  is at its minimum length at this point. Motor  1  can be pulled out by motor  2  once all slack is taken. Table 11 shows the feed-rate of motors  1  and  2  at this point. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 11 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 D: Body at top rear of vehicle 
                 1. 0% (able to be pulled out) 
               
               
                   
                   
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0066]    As shown in  FIG. 9E   1  as the body  100  comes over back of vehicle both sensors C and D are used to detect the body  100 . Detection of the body  100  by sensors C and D must overlap. Table 12 shows the feed-rate of motors  1  and  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 12 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 C: Body on vehicle 
                 1. 0% (able to be pulled out) 
               
               
                   
                 D: Body at top rear of vehicle 
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0067]      FIG. 9F  shows that as the body  100  clears the back of vehicle, sensor C continues to detect body  100  on the vehicle. Table 13 shows the feed-rate of motors  1  and  2  at this point. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 13 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 C: Body on vehicle 
                 1. 0% (able to be pulled out) 
               
               
                   
                   
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0068]    As the body  100  is pulled onto the vehicle, as shown in  FIG. 9G , the tilt is controlled by motor  2  and tension in motor  1  cable  70 . Table 14 shows the feed-rate of motors  1  and  2 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 14 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 C: Body on vehicle 
                 1. 0% (able to be pulled out) 
               
               
                   
                   
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0069]    As shown in  FIG. 9H , the body  100  is pulled onto the vehicle. Table 15 shows the feed-rate of motors  1  and  2  at this point. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 15 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 C: Body on vehicle 
                 1. 0% (able to be pulled out) 
               
               
                   
                   
                 2. 100% power feeding in 
               
               
                   
                   
               
             
          
         
       
     
         [0070]    Finally,  FIG. 9I  shows that as the body  100  is pulled over sensor A, the body  100  automatically locks into place. Sensor A then switches motor  2  off. Both motors  1  and  2  are deactivated, as shown in Table 16. The vehicle can then be simply driven away. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 16 
               
               
                   
                   
               
               
                   
                 Active Sensors: 
                 Motors: 
               
               
                   
                   
               
             
             
               
                   
                 A. Body in lock position 
                 None 
               
               
                   
                 C: Body on vehicle 
               
               
                   
                   
               
             
          
         
       
     
         [0071]      FIGS. 10A to 10C  show how the present invention can also be implemented as part of a trailer  90 . As before, the chassis frame  10  can be attachable or integrally formed with the trailer  90 . In the example shown in  FIGS. 10A to 10C , the vehicle body  100  is a toilet block. Clearly, being able to lower a toilet block directly onto ground level has enormous advantages in terms of disabled access. The skilled person will appreciate that the present invention can be implemented using any number of vehicle body types: for example, a box cab, a Luton cab, a flat deck, tipper, refrigerated rear cab, minibus, horse box, cement mixer, breakdown lorry, street light lift, bowsers and the like for liquid or bulk material, live stock carrying cabs, catering stands, mobile grandstands or mobile toilets etc. to be utilised for a variety of different purposes 
         [0072]      FIG. 11  is a perspective view from the rear which shows further detail of the tilt frame  28 , mounted at the rear of the chassis frame  10 , and the rear cable guide roller  20  which is used to guide the ON and OFF cables  68  and  70  when performing a mounting or demounting operation.  FIG. 11  shows that a pair of spring retainer clips  110  are used to retain each off the ON cables  68  above the rear cable guide roller  20  when the connector plate  50  and ON and OFF cables  68  and  70 , respectively, have been fed out. Without the spring clips  110 , the ON cables  68  are able to move in various directions and can be inadvertently moved away by an operator from their correct position above the rear cable guide roller  20 . During a mounting operation, as the connector plate  50  is pulled over the rear cable guide roller  20 , the spring retainer clips  110  are able to disengage the ON cables  68  allowing the connector plate  50  to be pulled up towards the winch mechanism  18 . 
         [0073]      FIG. 12  shows further detail of one of the spring retaining clips  110  shown in  FIG. 11 , which consist of two fingers  112  which are mounted through pivots  114  to the chassis frame  10 . A resilient member, such as a spring  118 , biases the two fingers  112  together, and which effectively forms an aperture  116  capable of receiving and retaining the ON cable  68 . The ON cable  68  is able to be pulled out of the spring retainer clip  110  only by a movement upwards in a direction away from the pivot point. 
         [0074]    Various alterations and modifications may be made to the present invention without departing from the scope of the invention.