Patent Publication Number: US-2010108467-A1

Title: Apparatus, system and method for moving a vehicle from dual belt conveyor to dual belt conveyor

Description:
FIELD OF THE INVENTION 
     Embodiments of the invention are directed to apparatus, systems and methods for transferring a vehicle from one dual belt conveyor to another dual belt conveyor and more particularly from at least a dual belt entrance conveyor of a car wash to a dual belt wash conveyor in the car wash wherein the vehicle may be in a variety of states including but not limited to park, neutral, foot brake engaged or emergency brake engaged. 
     BACKGROUND OF THE INVENTION 
     Conveyance systems are well known for moving vehicles along a direction of travel, such as along an assembly line in an automotive assembly plant or through a car wash tunnel. 
     One type of conveyor utilized particularly in conventional car washes is a chain conveyor having spaced, large, upwardly extending lugs which positively engage a wheel of the vehicle and act to drag the vehicle through the car wash tunnel. The vehicle&#39;s transmission is placed in neutral to permit the wheels of the vehicle to rotate on the floor of the carwash tunnel as the vehicle is dragged by the lug. The engaged wheel is guided throughout the car wash tunnel by tracks which align the wheels and prevent skewing of the vehicle. Should the wheels of the vehicle be prevented from rotating, such as by placing the drivetrain in Park or one or more of the footbrake or the emergency brake being engaged, the vehicle may be damaged when engaged with the lug. 
     It is known in the automotive industry, particularly in the assembly thereof, to utilize endless belt conveyors to support and carry a vehicle on the belt(s) along the direction of travel. The conveyor may comprise a single belt or dual, spaced apart, substantially parallel belts. A surface of the belts may or may not be cleated. Where two or more end-to-end conveyors are utilized to move the vehicle the desired distance, the vehicle must be transitioned across a gap formed therebetween. One common transition used in belt-to-belt transfer is a plate positioned across the gap between the belts. Another common transition is one or more rollers positioned in the gap. 
     Vehicles carried on belt conveyors typically have the wheels locked and therefore non-rotatable, such as when the drivetrain is in Park or when brakes, including the emergency brake, are applied. In the locked state, the wheels of the vehicle are carried by the conveyor surface and movement of the conveyor supplies sufficient momentum to overcome any force encountered by the wheels at the conventional transition. If however the vehicle&#39;s drivetrain is placed in neutral and the wheels are rotatable, the momentum caused by the conveyor would merely cause the wheels engaged in the gap to rotate and the vehicle would not be advanced over the gap or the conventional transition. Thus, conventional belt conveyor systems either require that the wheels be in a locked state to permit transition from belt to belt. 
     U.S. Pat. No. 7,278,533 to Horn teaches two, dual, endless belt conveyors oriented end-to-end for use in a carwash. Horn requires that the vehicle&#39;s drivetrain be placed in Park once the vehicle has been driven onto the entrance conveyor to lock the wheels against rotation. The locked wheels are thereafter pushed by the momentum of the conveyor over a single transfer roller fit within the gap between the entrance conveyor and the wash conveyor. 
     Despite warnings to the contrary, it is known that operators may place the vehicle in the locked state or the freewheeling state. This becomes particularly problematic in unmanned car washes which utilize belt conveyors and the vehicle&#39;s operator places the vehicle in neutral. The wheels are therefore freewheeling and can hang up in gaps at the transitions between belts, the vehicle potentially becoming stalled at the transition. Further, the vehicle may skew if passed over the transition, particularly if the rotatable wheels are not aligned with the direction of travel. 
     As a further complication in belt conveyors, Applicant believes that should the wheels be placed in the locked state and the vehicle successfully reach an end of the conveyor, the vehicle may be damaged as the front wheels of the vehicle exit from the final conveyor onto a surface outside the carwash while the rear wheels remain on the moving conveyor. 
     As well safety concerns are well known in the industry whenever there is a gap or nip formed between rollers or belts. It is possible that should the gap be large enough, personnel may engage with the gap, such as with their feet and severe injury is known to result. 
     Thus, there is an interest, particularly in the car wash industry, for a conveyance system for vehicles which provides safe and reliable movement of a vehicle, regardless the rotational state of the wheels of the vehicle, permits unimpeded and aligned transfer of the vehicle from belt to belt in a multi-conveyor system and minimizes any gap between conveyors and transitions therebetween to prevent personnel injury. 
     SUMMARY OF THE INVENTION 
     Embodiments of the invention facilitate transfer of a vehicle from one dual belt conveyor to another dual belt conveyor, particularly when the wheels of the vehicle are freewheeling such as when the drivetrain is placed in neutral. Transitions between the belts of one conveyor and the belts of another end-to-end oriented conveyor are offset along a direction of travel. The offset transitions result in only one wheel of the vehicle crossing a transition at any one time minimizing resistance acting against the vehicle during the transfer from conveyor to conveyor. Thus, the vehicle is transferred substantially without impedance from one conveyor to another conveyor. 
     In one broad aspect of the invention, a system for transferring a vehicle along a direction of travel from discharge ends of a first pair of belts to intake ends of a second pair of belts oriented as end-to-end belts, the vehicle having freewheeling wheels, comprises: a pair of passive transitions positioned between the first and second pairs of belts, the transitions being offset along the direction of travel so that only one transitioning, freewheeling wheel is supported on one of the pair of passive transitions at a time and imposes a resistance force at a first resistance threshold thereon; a plurality of cleats spaced along at least one belt of the first pair of belts and; a plurality of cleats spaced along on at least one belt of the second pair of belts, wherein a cleat of the plurality of cleats engages and imposes at least a minimum transitioning force on at least one freewheeling wheel, the at least a minimum transitioning force being greater than the first resistance threshold, for moving each transitioning wheel across the transitions and moving the vehicle between the first and second pairs of belts. 
     In another broad aspect of the invention, a method for carrying a vehicle, having freewheeling wheels, along a direction of travel from a first dual belt conveyor to a second dual belt conveyor, the vehicle having a first front wheel, a second front wheel, a first rear wheel, and a second rear wheel, comprising: providing a first transition positioned in a gap between a first side belt of the first dual belt conveyor and a first side belt of the second dual belt conveyor, and a second transition positioned in a gap between a second side belt of the first dual belt conveyor and a second side belt of the second dual belt conveyor; offsetting the first transition from the second transition along the direction of travel so that, when one of the first front wheel, second front wheel, first rear wheel or second rear wheel engages either of the first or second transition, all the remaining front and rear wheels are supported on either or both of the first and second dual belt conveyors; moving the first and second side belts of each of the first and second dual belt conveyors in the direction of travel for carrying the vehicle supported thereon; engaging at least one of a front wheel or rear wheel with a pushing cleat of a plurality of spaced cleats on at least one of the first side belt or second side belt of the first dual belt conveyor; pushing the engaged wheel with the pushing cleat until at least one of the front or rear wheels crosses the first or second transition; engaging at least a pulling cleat of a plurality of spaced cleats on at least one of the first side belt or second side belt of the second dual belt conveyor; and pulling at least a last rear wheel of the first or second rear wheel over the remaining second or first transition. 
     In embodiments of the invention, a first plurality of spaced cleats are formed on the first side belt of the first conveyor and a second plurality of cleats are formed on the second side belt of the second conveyor. Alternatively, either the first and second plurality of cleats are formed on each of the first side belts of the first and second conveyor or on each of the second side belts of the first and second conveyor or are formed on all of the belts of the first and second conveyors. A cleat engaging a wheel on the first conveyor acts to push on the cleat for pushing the vehicle. A cleat engaging a wheel on the second conveyor acts to push on the cleat for pulling the vehicle. 
     While embodiments of the invention are particularly suitable for transferring a vehicle having freewheeling wheels, the transfer however is also accomplished if at least some of the wheels of the vehicle are in a locked state. 
     In another broad aspect of the invention, a transition for transferring a freewheeling wheel of a vehicle between end-to-end belts of an endless belt conveyor system and in a direction of travel, comprises: a loop of recirculation rollers adapted to be positioned in a gap between the end-to-end belts, the loop of rollers being passively rotatable in the direction of travel; a fixed intake roller adapted to be supported in a gap between a discharge end of a first belt of the end-to-end belts and the loop of recirculation rollers; and a fixed discharge roller adapted to be supported in a gap between the loop of recirculation rollers and an intake end of a second belt of the end-to-end belts; wherein the fixed intake and discharge rollers are adapted to be spaced sufficiently from the discharge and intake ends of the end-to-end belts to permit unimpeded passage of the end-to-end belts thereby. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial plan view of an embodiment of the invention illustrating a first pair of substantially parallel spaced first and second endless belts forming a first conveyor and a second pair of substantially parallel spaced first and second endless belts forming a second conveyor, the first and second conveyors oriented end to end and having offset transitions positioned between end-to-end first side belts and end-to-end second side belts, portions of a central area between the belts having been removed for clarity; 
         FIG. 2  is a partial perspective view according to  FIG. 1 , portions of upper sections of the belts and coverings over a central area between the belts having been removed for clarity; 
         FIG. 3  is a perspective view of a transition for use between belts of conveyors oriented end-to-end for use in embodiments of the invention; 
         FIG. 4  is a plan view of the transition according to  FIG. 3 ; 
         FIG. 5  is a front view of the transition according to  FIG. 3 ; 
         FIG. 6  is a side view of the transition according to  FIG. 3 ; 
         FIG. 7  is a side view of the transition according to  FIG. 6 , a cover removed for viewing fixed and recirculation rollers therein; 
         FIGS. 8A-8F  are a series of schematic side views of the embodiment of  FIG. 1  illustrating passage of a cleat formed on an outer surface of one of the belts past a fixed intake roller of the transition of  FIG. 3 ; 
         FIGS. 9A-9G  are a series of schematic side views of first and second side belts of the embodiment of  FIG. 1  illustrating passage of first and second side wheels of a vehicle along the belts and over the offset transitions between the end-to-end oriented first and second side belts of the first and second pairs of belts; 
         FIGS. 10A-10G  are perspective views according to  FIGS. 9A-9G  respectively; 
       FIGS.  11 A 1 - 11 D 5  are schematic plan views illustrating the effect of engaging different of the wheels with cleats on opposing belts of the first and second pairs of belts; 
       FIGS.  12 A 1 - 12 E 5  are schematic plan views illustrating the effect of engaging different of the wheels with cleats on same side belts of the first and second pairs of belts; 
         FIGS. 13  is a side view of a belt of a conveyor, a return portion of the belt being supported by return rollers; and 
         FIG. 14  is a schematic plan view of a car wash having three dual belt conveyors according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In embodiments of the invention, shown in  FIGS. 1-7 , a conveyor system  1  carries a vehicle in a direction of travel T. The system  1  is particularly suited for use when a vehicle&#39;s wheels  2  are in the rotational or freewheeling state. The system  1  comprises a first pair  4  of substantially parallel first  6   a  and second  6   b  spaced apart endless belts and a second pair  10  of substantially parallel spaced apart first  8   a  and second  8   b  endless belts. The first pair of belts  4  forms a first dual belt conveyor  12  and the second pair of belts  10  forms a second dual belt conveyor  14 . Corresponding of the belts  6   a , 6   b , 8   a , 8   b  of the first and second dual belt conveyors  12 , 14  are oriented end-to-end as end-to-end belts. 
     A first side transition  20  is positioned in a gap  22  between a discharge end  23  of the first side belt  6  a of the first pair of belts  4  and an intake end  25  of the first side belt  8   a  of the second pair of belts  10 . A second side transition  24  is positioned in a gap  26  between the discharge end  27  of the second side belt  8   a  of the first pair of belts  4  and an intake end  28  of the second side belt  8   b  of the second pair of belts  10 . The transitions  20 , 24  are passive as the transitions  20 , 24  do not act to drive the wheels  2  of the vehicle but merely act rollably to support the wheels  2  to transition from conveyor  12  to conveyor  14 . Suitable transitions  20 , 24  could include a roller or rollers. 
     Cleats  30  are provided to engage the wheels  2  of the vehicle. A plurality of cleats  30  are spaced along at least one belt of the first pair of belts  4  and a plurality of cleats  30  spaced along on at least one belt of the second pair of belts  10 . The cleats  30  project from an outer surface  32  of at least one of the first or second side belts  6   a ,  6   b  of the first pair of belts  4 . The cleats  30  engage at least one wheel  2  of the vehicle to push the wheel  2  of the vehicle. By pushing a wheel  2 , a pushing cleat advances the vehicle as the remaining wheels  2  sequentially reach the first or second transition  20 ,  24 . Thus the vehicle is transferred, one wheel  2  at a time over the transitions  20 , 24  from the first conveyor  12  to the second conveyor  14 . As an exception, a last transitioning wheel  2 L is pulled over a remaining transition  20 , 24  by a pulling cleat  30  on the second conveyor  14  pushing on a wheel  2  which has crossed the transitions  20 , 24 . Thus, the action of the cleats  30 , pushing on the wheels  2  of the vehicle, causes a push or pull on the vehicle resulting in substantially unimpeded transfer of the wheels  2  across the passive first and second transitions  20 ,  24  between the conveyors  12 ,  14 . 
     Further, the first transition  20  is offset relative to the second transition  24  sufficiently such that only one wheel  2  of the vehicle, a transitioning wheel  2   t , is crossing either the first or second transition  20 ,  24  at any one time. The remaining front and rear wheels  2  are supported on either or both of the first and second pairs of belts  4 , 10  of the first and second conveyors  12 ,  14 . In other words, when any one of the vehicle&#39;s wheels  2   t  is on one of the first or second transition  20 , 24 , there remains three points of contact between the vehicle and the belts  6   a , 6   b , 8   a , 8   b  of one or both of the conveyors  12 ,  14 . Thus, the only resistance to movement of the vehicle is caused by one wheel  2  at the transitions  20 , 24 . 
     Gaps  22 , 26  are found between discharge ends  23 , 27  and intake ends  25 , 28  of the belts  6   a , 6   b , 8   a , 8   b  of the conveyors  12 , 14 . Resistance to movement of the wheels  2  across the transition is at least in part a function of a width of the gap  22 , 26 . At least a portion of the wheel  2  will fall into the gap  22 , 26  and thereafter must climb out of the gap  22 , 26  in order to move in the direction of travel T. A wider gap  22 , 26  will permit a greater portion of the wheel  2  to drop into the gap  22 , 26  and imposes a higher resistance force against further motion of the wheel  2  in the direction of travel T. A narrower gap  22 , 26  will engage a lesser portion of the wheel  2  and thus will result in less resistance force against the wheel  2 . Additionally, there may be other resistance forces such as a result of the action of the wash brushes against the vehicle creating a cumulative resistance force. 
     Thus, in embodiments of the invention, the first and second transitions  20 , 24  are designed to minimize the size of the gap  22 , 26  while still providing a minimum tolerance for permitting the belts  6   a , 6   b , 8   a , 8   b  and cleats  30  thereon unimpeded passage by the transitions  20 , 24 . A cleat height is sufficiently high so as to provide at least a minimal cleat or transitioning force to a freewheeling wheel  2  to overcome at least the resistance force when a vehicle encounters a first resistance threshold R 1  of one wheel  2  crossing either the first or second transition  20 ,  24  at any one time. 
     Having reference again to  FIGS. 1-7 , and in embodiments of the invention, the transition  20 ,  24  extends across a length of the gap  22 , 26  being substantially a width of each of the belts  6   a , 6   b , 8   a , 8   b.    
     Having reference as well to  FIGS. 8A-8F , the offset first and second transitions  20 , 24  comprise a fixed intake roller  44  adjacent the discharge ends  23 , 27  of each of the belts  6   a , 6   b  of the first conveyor  12  and a fixed discharge roller  48  supported in gap  22 , 26 , adjacent the intake ends  25 , 28  of each of the belts  8   a , 8   b  of the second conveyor  14 . The fixed intake roller  44  and the fixed discharge roller  48  are spaced from the discharge ends  23 , 27  and the intake ends  25 , 28  of the belts  6   a , 6   b , 8   a , 8   b  sufficient so as to permit passage of the belts  6   a ,  6   b ,  8   a ,  8   b  and cleats  30  thereby. 
     In an embodiment of the invention, the fixed intake and fixed discharge rollers  44 , 48  are ultra high-molecular weight polyethylene (UHMWPE) rollers so as to be sufficiently strong to support the weight of vehicles thereon and to withstand repeated use. The UHMWPE rollers are mounted on stainless steel shafts, the UHMWPE acting as a bearing on the shafts. 
     In embodiments of the invention, a plurality of the cleats  30  are spaced along at least one of the first side belts  6   a , 8   a  or second side belts  6   b , 8   b  of each of the first pair of belts  4  and the second pair of belts  10 . The cleats  30  engage and push at least one of the freewheeling wheels  2  of the vehicle for pushing or pulling the vehicle over the first and second transitions  20 , 24 . Where at least one wheel  2  of the vehicle is engaged by a cleat  30  on the first conveyor  12 , the vehicle is pushed over the transition  20 , 24 . Where at least a second wheel  2  is engaged by a cleat  30  on the second conveyor  14 , the vehicle is pulled over the first and second transitions  20 , 24 . 
     Each cleat  30 , of the plurality of cleats  30 , projects upwardly from the belts  6   a , 6   b , 8   a , 8   b  sufficient to engage and push the wheel  2  with at least minimal cleat or transitioning force required for pushing, pulling, or pushing and pulling the vehicle to overcome at least the first resistance threshold R 1  formed when a transitioning wheel  2   t  engages one of either the first or second transition  20 , 24 . 
     If the cleat height is too low, the resistance force exceeds the transitioning force and the cleat  30  will pass beneath a freewheeling wheel  2  in lockstep with the wheel  2 , lifting the wheel  2  and rotating the wheel  2  backwards causing the vehicle to cease moving forward. In order for this to occur, the resistance force must also be greater than the total of a force vector necessary to lift a normal force of the vehicle supported by the wheel  2 . Once lifted, the wheel  2  can then roll backward down a lee side of the cleat  30 . 
     The cleat height is therefore designed to be equal to or greater than the first resistance threshold R 1 . The minimal cleat or transitioning force is minimally greater than a normal resistance force or first resistance threshold R 1  at a transition  20 , 24  to permit the cleat  30  to typically engage and push a wheel  2  thereover. As a result of using only the minimal transitioning force, the cleat  30  can pass beneath the wheel  2  in the case where there may be a temporary spike in the resistance force, and the wheel  2  can then be engaged by a subsequent spaced cleat  30  for pushing the wheel  2  across the transition  20 , 24  when the resistance force returns to design levels. 
     Further, the cleats  30  extend upwardly therefrom sufficiently to permit passage of the cleats  30  beneath at least some of the wheels  2  of the vehicle when remaining of the wheels  2  of the vehicle encounter the first resistance threshold R 1 . For example the cleats  30  extend upwardly therefrom a sufficient height such that the cleats  30  are safely able to pass under the rear wheels  2 R when at least one of the wheels  2  of the vehicle encounters a higher second resistance threshold R 2 . The higher second resistance threshold R  2  might occur when front wheels  2 F, in a locked state, exit the second conveyor  14  onto a fixed surface and freewheeling rear wheels  2 R remain on the driven second conveyor  14 . 
     Additionally, the cleats  30  extend upwardly therefrom only a sufficient height such that the cleats  30  are caused to pass under the rear wheels  2 R when at least one of the wheels  2  of the vehicle encounters a even higher third resistance threshold R 3 . The even higher third resistance threshold R 3  might occur when front wheels  2 F, in a locked state, exit the second conveyor  14  onto a fixed surface and locked rear wheels  2 R remain on the moving, second conveyor  14 . 
     In the case of a vehicle where the wheels  2  are in a locked state, the resistance force must exceed the total of the force vector and a frictional resistance force to drag the cleat  30  across the locked wheel&#39;s surface. 
     The second and third resistance thresholds R 2 , R 3  are established so that damage to the vehicle is avoided. 
     While the description provided thus far has been restricted to the discussion of first and second pairs of belts  4 , 10  forming the first and second dual belt conveyors  12 , 14 , one of skill in the art would appreciate that embodiments of the invention are not limited to only two conveyors. It is within the scope of the invention to provide an infinite number of conveyors oriented end-to-end and having transitions supported therebetween. 
     In operation, as shown in  FIGS. 9A-9G ,  10 A- 10 G,  11 A 1 - 11 D 5  and  12 A 1 - 12 E 5 , an operator drives a vehicle onto the first dual belt conveyor  12 . The state of the vehicle can be non-rotational or locked, including placing the drivetrain in Park or engaging the foot brake or emergency brake or can be rotational or freewheeling, such as placing the drivetrain in Neutral. 
     In an embodiment of the invention, a first plurality of spaced cleats  30  are formed on the first side belt  6   a  of the first dual belt conveyor  12  and a second plurality of spaced cleats  30  are formed on the second side belt  8   b  of the second dual belt conveyor  14 . 
     In this embodiment, the first and second conveyors  12 , 14  are driven for carrying the vehicle in the direction of travel T. A cleat  30  on the first side belt  6   a  is caused to engage at least one of a first front wheel  2 F 1  or a first rear wheel  2 R 1  on a first side of the vehicle. The cleat  30 , having a design height as previously described, acts to push the engaged first front or first rear wheel  2 E as remaining wheels  2  sequentially encounter resistance force at the transitions  20 , 24  and acts with at least the minimal transition force to overcome the resistance force so as to move the transitioning wheel  2   t  of the vehicle over the transitions  20 , 24 . 
     If the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first front wheel  2 F 1  (FIG.  11 A 1 ), the cleat  30  pushes a second front wheel  2 F 2  on the second side belt  6   b , now the transitioning wheel  2   t , over the second transition  24  (FIG.  11 A 2 ), after which the second front wheel  2 F 2  is engaged by a cleat  30  on the second side belt  8   b  (FIG.  11 A 3 ) for sequentially pulling the remaining wheels  2 , being the first front wheel  2 F 1  (FIG.  11 A 3 ) and both of a second rear wheel  2 R 2  and a first rear wheel  2 R 1 , being the last wheel  2 L (FIGS.  11 A 4  and  11 A 5 ), over the first and second transitions  20 , 24 . 
     As shown in FIGS.  11 B 1 - 11 B 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first rear wheel  2 R 1  on the first side of the vehicle (FIG.  11 B 1 ), the cleat  30  acts to sequentially push the second front wheel  2 F 2  (FIG.  11 B 2 ), the first front wheel  2 F 1  (FIG.  11 B 3 ) and the first rear wheel  2 R 1  (FIG.  11 B 4 ) over the second and first transitions  20 , 24 , respectively. Either the second front wheel  2 F 2  (FIG.  11 B 5 ) or possibly the second rear wheel (not shown) thereafter engages a cleat  30  on the second side, cleated belt  8   b  of the second conveyor  14  for pulling the first rear wheel  2 R 1 , over the first transition  20 . 
     Alternatively, as shown in FIGS.  11 C 1 - 11 C 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first rear wheel  2 R 1  on the first side of the vehicle (FIG.  11 C 1 ), the cleat  30  acts to push the second front wheel  2 F 2  (FIG.  11 C 2 ) over the second transition  24 . The second front wheel  2 F 2  (FIG.  11 B 5 ) may thereafter engage a cleat  30  on the second side cleated belt  8   b  of the second conveyor  14  for sequentially pulling the first front wheel  2 F 1  over the first transition  20 , the second rear wheel  2 R 2  over the second transition  24  and the first rear wheel  2 R 1  over the first transition  20 . 
     Alternatively as shown in FIGS.  11 D 1 - 11 D 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first rear wheel  2 R 1  (FIG.  11 D 1 ) for pushing the second front wheel  2 F 2  over the second transition  24  (FIG.  11 D 2 ) as previously described, the first rear wheel  2 R 1  may remain engaged with the cleat  30  on the first side belt  6   a  when the second front wheel  2 F 2  engages a cleat  30  on the second side belt  8   b  of the second conveyor  14  (FIG.  11 D 3 ), the two engaged wheels  2 R 1 , 2 F 2  thereafter act together to push and pull the first front wheel  2 F 1  (FIG.  11 D 3 ) and the second rear wheel  2 R 2  (FIG.  11 D 4 ) over the first and second transitions  20 , 24 , respectively, Once the first rear wheel  2 R 1  reaches the first transition  20 , only the second front wheel  2 F 2  remains engaged with the cleat  30  on the second side belt  8   b  of the second conveyor  14  and it acts to pull the remaining first rear wheel  2 R 1  over the first transition  20  (FIG.  11 D 5 ). 
     In an embodiment of the invention shown in FIGS.  12 A 1 - 12 E 5 , a plurality of spaced cleats  30  are formed on either of the first or second side belt  6   a , 6   b  of the first conveyor  12  and on the same side, being the first or second side belt  8   a , 8   b  on the second conveyor  14 . Thus only wheels  2  on one side of the vehicle are engaged by the cleats  30  for pushing and pulling the vehicle over the transitions  20 , 24 . 
     If the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first front wheel  2 F 1  (FIG.  12 A 1 ), the cleat  30  pushes the second front wheel  2 F 2  on the second side belt  6   b  over the second transition  24  (FIG.  12 A 2 ). When the first front wheel  2 F 1  engages the first transition  20  (FIG.  12 A 3 ), the first rear wheel  2 R 1  is engaged by a cleat  30  on the first side belt  6   a  for pushing the first front wheel  2 F 1  over the first transition  20 . The first rear wheel  2 R 1  remains engaged with the cleat  30  for pushing the second rear wheel  2 R 2  over the second transition  24  (FIG.  12 A 4 ) after which the first front wheel  2 F 1  engages a cleat  30  on the first side belt  8   a  of the second conveyor  14  (FIG.  12 A 5 ) for pulling the first rear wheel  2 R 1 , being the last wheel  2 L (FIGS.  11 A 4  and  11 A 5 ), over the first transition  20 . 
     Alternatively, as shown in FIGS.  12 B 1 - 12 B 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first front wheel  2 F 1  (FIG.  12 B 1 ), the cleat  30  pushes the second front wheel  2 F 2  on the second side belt  6   b  over the second transition  24  (FIG.  12 B 2 ). When the first front wheel  2 F 1  engages the first transition  20  (FIG.  12 B 3 ), the first rear wheel  2 R 1  is engaged by a cleat  30  on the first side belt  6   a  for pushing the first front wheel  2 F 1  over the first transition  20 . The front wheel  2 F 1  thereafter engages with the cleat  30  on the first side belt  8   a  of the second conveyor  14  for pulling the second rear wheel  2 R 2  (FIG.  12 B 4 ) over the second transition  24  and the first rear wheel  2 R 1 , being the last wheel  2 L (FIG.  12 B 5 ), over the first transition  20 . 
     As shown in FIGS.  12 C 1 - 12 C 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first rear wheel  2 R 1  on the first side of the vehicle (FIG.  12 C 1 ), the cleat  30  acts to sequentially push the second front wheel  2 F 2  (FIG.  12 C 2 ), the first front wheel  2 F 1  (FIG.  12 C 3 ) and the first rear wheel  2 R 1  (FIG.  12 C 4 ) over the second and first transitions  20 , 24 , respectively. Thereafter, the first front wheel  2 F 1  (FIG.  11 B 5 ) engages a cleat  30  on the first side belt  8   a  of the second conveyor  14  for pulling the first rear wheel  2 R 1 , over the first transition  20 . 
     Alternatively, as shown in FIGS.  12 D 1 - 12 D 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first front wheel  2 F 1  on the first side of the vehicle (FIG.  12 D 1 ), the cleat  30  acts to push the second front wheel  2 F 2  (FIG.  12 D 2 ) over the second transition  24 . When the first rear wheel  2 R 1  engages the first transition  20 , the first rear wheel  2 R 1  engages a cleat  30  on the first side belt  6   a  of the first conveyor for pushing the first front wheel  2 F 1  over the first transition  20 . Thereafter, the first front wheel  2 F 1  may engage a cleat on the first side belt  8   a  of the second conveyor  14 , the first rear wheel  2 R 1  remaining engaged with a cleat  30  and thus the second rear wheel  2 R 2  is both pushed and pulled over the second transition  24 . As soon as the first rear wheel  2 R 1  reaches the first transition, it releases the cleat  30  and the first rear wheel  2 R 1  is pulled over the first transition  20 . 
     Alternatively, as shown in FIGS.  12 E 1 - 12 E 5 , if the cleat  30  on the first side belt  6   a  of the first conveyor  12  engages the first rear wheel  2 R 1  (FIG.  12 E 1 ) for pushing the second front wheel  2 F 2  over the second transition  24  (FIG.  12 E 2 ) and the first front wheel  2 F 1  over the first transition  20  (FIG.  12 E 3 ), as previously described, the first rear wheel  2 R 1  may remain engaged with the cleat  30  on the first side belt  6  a when the first front wheel  2 F 1  engages a cleat  30  on the first side belt  8   a  of the second conveyor  14  (FIG.  12 E 4 ). The two engaged wheels  2 R 1 , 2 F 1  thereafter act together to push and pull the second rear wheel  2 R 2  (FIG.  112 E 4 ) over the first and second transitions  20 , 24 , respectively, Once the first rear wheel  2 R 1  reaches the first transition  20  (FIG.  12 E 5 ), only the first front wheel  2 F 1  remains engaged with the cleat  30  on the first side belt  8   a  of the second conveyor  14  and it acts to pull the remaining first rear wheel  2 R 1  over the first transition  20  (FIG.  12 E 5 ). 
     In the case where the plurality of spaced cleats  30  are formed on all of the belts  6   a , 6   b , 8   a , 8   b , the spacing of the cleats  30  between the first side belt  6   a , 8   a  and the second side belt  6   b , 8   b  of the first and the second conveyors  12 , 14  are preferably synchronized. Any number or all of the wheels  2  of the vehicle may be engaged by a cleat  30  on any of the cleated belts  6   a , 6   b , 8   a , 8   b  for pushing the wheels  2 . Depending upon which of the wheels are engaged and with which cleats  30 , the wheels  2  of the vehicle are pushed and pulled over the transitions  20 ,  24 , the last transitioning wheel  2 L being pulled over the second transition  24 . 
     In embodiments of the invention particularly suited for cold climates, best seen in  FIGS. 3-7  and  8 A- 8 F, each of the first and second transitions  20 , 24  further comprises a loop  40  of recirculation rollers  42  positioned in the gap  22 , 26  between the first conveyor  12  and the second conveyor  14  and extending across a width of the transition  20 ,  24 . The loop  40  is positioned between the fixed intake roller  44  and the fixed discharge roller. The loop  40  is oriented so that the loop  40  is passively rotatable in the direction of travel T, each of the rollers  42  therein also being rotatable so as to break up any ice which tends to form thereon. 
     In embodiments of the invention the rollers  42  are made of stainless steel, such as recirculation rollers  42  available from Hillman Rollers, Marlboro, N.J., 07746, USA. 
     The fixed intake roller  44  forms a discharge gap  46  between the discharge ends  23 , 27  of each of the first and second side belts  6   a ,  6   b  of the first dual belt conveyor  12  and the loop  40  of recirculation rollers  42  of the first and second transitions  20 ,  24 , respectively. The fixed discharge roller  48  forms an intake gap  50  between the loop  40  of recirculation rollers  42  of the first and second transitions  20 ,  24  and the intake ends  25 , 28  of each of the first and second side belts  8   a ,  8   b  of the second dual belt conveyor  14 . The fixed intake and fixed discharge rollers  44 , 48  are sized so as to substantially fill the discharge gap  49  and the intake gap  50  while leaving sufficient space therein to permit unimpeded passage of the endless belts  6   a , 6   b , 8   a , 8   b  and the cleats  30  thereby. 
     In an embodiment of the invention, the fixed intake roller  44 , the loop  40  of recirculation rollers  42  and the discharge roller  48  form a set of transition rollers  52  having a limited length dictated by the load the set of transition rollers  52  can support. A plurality of sets of transition rollers  52  are positioned substantially parallel and side-by-side across the length of the gap  22 , 26  for forming the transition  20 , 24  to extend across a width of each belt. A width of each of the plurality of recirculation rollers  42  and the plurality of fixed intake and fixed discharge rollers  44 , 48  is selected such that each wheel  2  on the vehicle contacts at least a portion of each of two recirculation rollers  42 , 42 , two fixed intake rollers  44 , 44  and two fixed discharge rollers  48 , 48  as the wheel  2  crosses the transition  20 , 24 , regardless the positioning of the wheel  2  across the length of the transition  20 , 24 . 
     EXAMPLE A 
     In one example, as shown in  FIGS. 1-7 , embodiments of the invention are used in a car wash to move a vehicle into and through a wash tunnel  70 . The first pair  4  of substantially parallel endless first  6   a  and second  6   b  side belts form an entrance conveyor  12  which extends from external the wash tunnel  70  and into an entrance  72  of the wash tunnel  70  and onto which the operator drives the vehicle. 
     Once inside the entrance  72  of the wash tunnel  70 , a second pair  10  of substantially parallel endless first  8   a  and second  8   b  side belts forms a wash conveyor  14  which is oriented end-to-end with the entrance conveyor  12 . First and second transitions  20 , 24  according to an embodiment of the invention are supported between the first side belt  6   a  of the entrance conveyor  12  and the first side belt  8   a  of the wash conveyor  14  and the second side belt  6   b  of the entrance conveyor  12  and the second side belt  8   b  of the wash conveyor  14 . The vehicle is transferred from the entrance conveyor  12 , over the transitions  20 , 24  and onto the wash conveyor  14 , by the motion of the conveyors  12 , 14  in the direction of travel T and by the action of the cleats  30  to provide at least a minimal transitioning force to overcome at least a resistance force encountered as each of the wheels  2  of the vehicle sequentially reach and engage the first and second transitions  20 , 24 . 
     The vehicle can be placed in neutral (freewheeling state) or in park or the foot brakes or emergency brake can be applied (locked state) without affecting the operation of the carwash&#39;s conveyors  12 , 14  to move the vehicle through the car wash. 
     The height to which the cleats  30  project upwardly from the belts  6   a , 6   b , 8   a , 8   b  of the conveyors  12 , 14  is finely balanced to provide the at least the minimal transitioning force to overcome the resistance force while minimizing the  49 , 50  required between the transitions&#39; fixed intake rollers  44  and fixed discharge rollers  48  and the cleats  30  for permitting passage of the cleats  30  and belts  6   a , 6   b , 8   a , 8   b  thereby. If the cleat  30  does not extend high enough, the resistance force may permit the wheel  2  to roll backward over the cleat  30  as the wheel  2  engages the transition as previously described. If however, the cleat is higher to increase the transitioning force, causing the gaps  49 , 50  to be much larger, the resistance force may become too great and the transition force of the higher cleat is insufficient to overcome the greater resistance force as previously discussed. 
     Should there be additional, instantaneous resistance at the moment a wheel  2  reaches a transition  20 , 24 , the engaged cleat  30 E may not be able to provide sufficient transition force to overcome the instantaneous resistance force. The cleat would therefore be unable to push the wheel  2  onto and over the transition  20 , 24 . In this case, the engaged cleat  30 E may be caused to slip under the wheel  2 . The wheel  2  is then engaged up by a following cleat  30  which, provided the resistance force has returned to a design magnitude, will cause the wheel  2  to be moved onto and over the transition  20 , 24 . 
     The transition force caused by the cleats  30  pushing on a wheel  2  acts as either a vehicle pushing force or a vehicle pulling force depending upon which of the cleats  30  on which of the belts  6   a , 6   b , 8   a , 8   b  engages at least one wheel  2  of the vehicle. 
     The first and second side belts  6   a , 6   b , 8   a , 8   b  of the entrance and wash conveyors  12 , 14 , referred to as “the belts” for the purposes of the following discussion, are supported above a floor  74  of the car wash tunnel by a support frame system  76  such as is understood by one of skill in the art. Each of the belts  6   a , 6   b , 8   a , 8   b  is about 896 mm (about 35 inches) in width. The belts  6   a , 6   b , 8   a , 8   b  of each of the entrance and wash conveyors  12 , 14  are spaced about 710 mm (about 28 inches) apart. Thus, each conveyor  12 , 14  is capable of supporting thereon a wide range of vehicles having from a minimum to a maximum known wheel base. Further, if the driver does not center the vehicle on the belt  6   a , 6   b , 8   a , 8   b , regardless how far to one edge or the other of the belts  6   a , 6   b , 8   a , 8   b  the vehicle is positioned, the wheels  2  will be engaged by both of the belts  6   a , 6   b , 8   a , 8   b  regardless a width of the vehicle from wheel  2 F 1 , 2 R 1  to wheel  2 F 2 ,  2 R 2 . 
     The first and second transitions  20 , 24  are offset from each other along the direction of travel by about 520 mm (about 20 inches) such that, even when a vehicle has a short wheel base, only one wheel  2  of the vehicle will engage and cross one transition  20 , 24  at any one time. The remaining wheels  2  provide at least three points of contact between the vehicle and the belts  6   a , 6   b , 8   a , 8   b  for maintaining vehicle positioning on the belts  6   a , 6   b , 8   a , 8   b  and reduce the resistance force encountered by the vehicle at the transitions  20 , 24 . 
     Particularly advantageous in a car wash embodiment, the action of the recirculation rollers  42  acts to break up and prevent ice build up at the transitions  20 , 24  when used in climates which are susceptible to freezing temperatures. 
     In an embodiment of the invention, the support frame system  76  is positioned within a trench in the wash tunnel  70 . A plurality of cleats  30  are spaced about 320 mm (about 13 inches)±63.5 mm (2.5 inches) apart along a length of the first side belt  6   a  of the first conveyor  12  and the opposing second side belt  8   b  of the second conveyor  14 . The cleats  30  in cross-section are arcuate in profile to assist the cleat to pass under the wheels  2  of the vehicle should it be necessary to do so. The cleats  30  project upwardly about 12.5 mm (about 0.49 inch) to engage the wheels  2  of the vehicle and prevent the vehicle when placed in neutral, from rolling backward on the entrance conveyor  12 , particularly when the entrance conveyor  12  is put into motion. Further, the cleats  30  extend transversely across substantially an entirety of the width of the belt  6   a , 6   b , 8   a , 8   b.    
     In one embodiment of the invention, the cleats  30  and at least portions of the belts  6   a , 6   b , 8   a , 8   b  may be perforated to permit drainage of wash fluids therethrough. The endless belts  6   a , 6   b , 8   a , 8   b  are modular plastic belts formed using a plurality of interconnected links upon which the cleats  30  are formed or otherwise attached thereto. 
     The entrance and wash conveyors  12 , 14  are generally sloped about 12 mm (0.49 inches) to about 19 mm (0.75 inches) over the length of the entrance and wash conveyors, being about 25 m (82 feet), to encourage drainage and aid in ensuring forward momentum of the vehicle. 
     Having reference to  FIG. 13 , a plurality of return rollers  80  extend transversely beneath a lower, return portion  82  of each of the endless belts  6   a , 6   b , 8   a , 8   b  for supporting the return portion  82  thereon. The plurality of return rollers  80  are variably spaced along a length of each of the belts  6   a , 6   b , 8   a , 8   b  so as to minimize harmonics which can occur such as when the plurality of return rollers  80  are spaced evenly therealong. Typically, there is a certain amount of slack tolerated in the return portion of the belts  6   a , 6   b , 8   a , 8   b  as a result of belt elasticity, expansion and contraction, resulting from changes in temperature, wear conditions and the like. The variably spaced return rollers  80  support the return portion  82  of the belts  6   a , 6   b , 8   a , 8   b  thereon so as to minimize the harmonic effects in the return portion  82  between the plurality of variably spaced return rollers  80  for maximizing smooth operation of the belts  6   a , 6   b , 8   a , 8   b.    
     In the embodiment of the invention shown in  FIG. 13 , the plurality of return rollers  80  are variably spaced along the length of the belt&#39;s return portion  82  as shown in Table A. 
     
       
         
           
               
               
               
             
               
                 TABLE A 
               
               
                   
               
               
                 Return portion belt 
                 Spacing between return 
                 Spacing between return 
               
               
                 segment 
                 rollers (inches) 
                 rollers (m) 
               
               
                   
               
             
            
               
                 a 
                 43.6 
                 1.107 
               
               
                 b 
                 78.5 
                 1.994 
               
               
                 c 
                 35.5 
                 0.902 
               
               
                 d 
                 36.5 
                 0.927 
               
               
                 e 
                 35.5 
                 0.902 
               
               
                 f 
                 36.2 
                 0.919 
               
               
                 g 
                 36.0 
                 0.914 
               
               
                 h 
                 36.0 
                 0.914 
               
               
                 i 
                 35.5 
                 0.902 
               
               
                 j 
                 36.5 
                 0.927 
               
               
                 k 
                 35.5 
                 0.902 
               
               
                 l 
                 36.5 
                 0.927 
               
               
                 m 
                 36.0 
                 0.914 
               
               
                 n 
                 32.5 
                 0.826 
               
               
                 o 
                 35.0 
                 0.889 
               
               
                 p 
                 45.0 
                 1.143 
               
               
                 q 
                 35.0 
                 0.889 
               
               
                 r 
                 30.0 
                 0.762 
               
               
                 s 
                 22.2 
                 0.564 
               
               
                   
               
            
           
         
       
     
     Further, a diameter of the return rollers  80  is larger than conventionally used so as to permit the cleats  30  on the outer surface  32  of the belts  6   a , 6   b , 8   a , 8   b  to climb the return rollers  80  with minimal impedance of the motion of the belts  6   a , 6   b , 8   a , 8   b  thereover. 
     In an embodiment of the invention shown in  FIG. 14 , it is contemplated to use three dual belt conveyors, such as the entrance conveyor  12 , the wash conveyor  14  and a discharge conveyor  90 . The discharge conveyor  90  is a dual belt conveyor comprising a third pair  91  of first side and second side belts  9   a , 9   b  oriented end-to-end to the first and second side belts  8   a , 8   b  of the wash conveyor  14 . A third transition  92  and a fourth transition  94  are positioned between the first side belt  8   a  of the wash conveyor  12  and the first side belt  9   a  of the discharge conveyor  90  and the second side belt  8   b  of the wash conveyor  12  and the second side belt  9   b  of the discharge conveyor  90 , respectively. A discharge end  96  of the discharge conveyor  90  causes the vehicle to be discharged onto a fixed surface located outside an exit  98  of the wash tunnel  70 . 
     EXAMPLE B 
     Design of an optimum cleat height, as previously described, finely balances the height of the cleat so as to provide at least a minimum transitioning force to push against a wheel of the vehicle to overcome at least a first minimum resistance threshold acting against another wheel of the vehicle at either of the first or second transition. 
     A worst case scenario for design of the cleat height is a vehicle having small wheels, where more of the wheel is engaged by the gaps and therefore the resistance is greater to the forward movement of the wheel over the transitions. 
     In one embodiment of the invention, an optimum cleat height was determined for a 1989 Pontiac Firefly having a tire size of 33 cm (13 inches). 
     As Table B illustrates, increasing the cleat height to attempt to achieve a greater pushing or transitioning force requires an increase in the discharge and intake gaps so as to permit the higher cleat to pass thereby. The increase in the gap size required to accommodate the higher cleat results in an increased resistance force acting against the wheels of the vehicle. 
     
       
         
           
               
               
               
               
             
               
                 TABLE B 
               
             
            
               
                   
               
               
                   
                   
                 Resistance 
                 Transitioning 
               
               
                 Cleat Height 
                 Gap mm 
                 Force 
                 Force 
               
            
           
           
               
               
               
               
               
            
               
                 mm 
                 *Roller/Cleat 
                 *Roller/Belt 
                 lbs 
                 lbs 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 3.5 
                 3.5 
                 15-20 
                 0 
               
               
                 2.5 
                 3.5 
                 6 
                 15-20 
                 5 
               
               
                 5 
                 3.5 
                 8.5 
                 15-20 
                 10 
               
               
                 7.5 
                 3.5 
                 11 
                 20-25 
                 15 
               
               
                 10 
                 3.5 
                 13.5 
                 25-30 
                 25 
               
               
                 12.5 
                 3.5 
                 16 
                 30-40 
                 40 
               
               
                 15 
                 3.5 
                 18.5 
                 40-60 
                 55 
               
               
                 17.5 
                 3.5 
                 21 
                 60-90 
                 75 
               
               
                   
               
               
                 *“Roller” refers to the fixed intake or discharge rollers 
               
            
           
         
       
     
     As one of skill would appreciate, an optimum height of 12.5 mm is minimally sufficient to overcome the resistance force during normal operations. Cleat heights of less than 12.5 mm do not provide sufficient transitioning force to overcome the resistance force. Increasing the cleat height above 12.5 mm results in a transitioning force which may be insufficient over the complete range of the resistance force and therefore is unreliable to transition a wheel of the vehicle during operation.