Patent Publication Number: US-7909560-B1

Title: Flatbed tow truck pivoting platform assembly

Description:
FIELD OF THE INVENTION 
     The present disclosure generally relates to an apparatus and method for a transporting vehicles and other similar sized objects. More particularly, the present disclosure relates to a vehicle carrier utilizing a pair of sliding interfaces interacting with a pivot arm to drive a carrier body between a loading configuration and a transport configuration. 
     BACKGROUND OF THE INVENTION 
     The purpose of the invention is to provide an apparatus for transporting large objects such as vehicles. Vehicle transport systems, commonly referred to as tow trucks, have been evolving in parallel with the automobile. There are several classifications of towing equipment, including a boom, a hook and chain, a wheel-lift, a flatbed, and an integrated system. 
     A boom is generally utilised for recovering vehicles that are in a ditch, culvert, over an embankment, or any place the vehicle cannot be safely backed-up to. A boom may or may not be used for towing a recovered vehicle. 
     A hook and chain, also known as a “sling” or “belt lift”, loops chains around the vehicle frame or axle, which is drawn aloft by a boom winch to rest against a pair of heavy rubberized mats so the customer&#39;s vehicle can be towed on its other axle. In today&#39;s environment, the use of slings is very limited, as they are known to scratch bumpers of cars. They are generally used for towing vehicles that have been in an accident or have one or two of the front or rear wheels missing or for pickup trucks and other vehicles that have steel bumpers 
     A wheel-lift evolved from the hook and chain technology, utilizing a large metal yoke that is fitted under the front or rear wheels to cradle them. The wheel-lift raises the front or rear end of the vehicle off the ground by a pneumatic or hydraulic hoist so it can be towed. This apparatus generally picks up the drive wheels of the vehicle (i.e. the front wheels if it is front wheel drive, the rear wheels if it is rear wheel drive). The lift only touches the tires, limiting any risk of damage to the towed vehicle. 
     A flatbed, also referred to as a rollback or a slide back carrier provides a carrier body placed over the entire trailer portion of a truck. The bed can be hydraulically inclined and moved to ground level, allowing the customer&#39;s vehicle to be placed onto the carrier body under its own power or pulled by a winch. 
     An integrated lift, also referred to as a “Self Loader” Snatcher, Quick Pick or Repossession Truck, integrates a boom and wheel-lift into a single unit. The integrated lift is generally installed onto light duty trucks to repossess vehicles or move illegally parked vehicles. Most have controls for the apparatus inside the cab of the tow truck to make quick pickup possible without the loss of time to exit the truck to manually hook up the vehicle. 
     These are the most common arrangements, but are by no means exclusive; as there are flatbed units that offer a wheel-lift, boom trucks that can recover but not tow, and wheel-lift units that offer a combination boom with sling. 
     Flatbed carriers utilize a slide and tilt mechanism that is integrated into the trailer portion of a chassis frame of a truck. The flatbed is coined from a flat carrier body used to load and transport a vehicle. The system is operated via a series of hydraulic pistons. One hydraulic piston adjusts the position of the carrier body along a longitudinal axis of the vehicle. A second hydraulic piston rotates the carrier body between a loading angle and a transporting angle. The carrier body is a single, planar surface. The carrier body needs to be positioned into a transport configuration, wherein the carrier body is drawn forward, locking the body into position via a pair of locking pins or receptacle located on the trailer portion of the frame, proximate the cab. A wheel lift may also be integrated onto some flatbed carriers. The wheel lift is affixed to the flatbed carrier frame as an appendage thereof. 
     Flatbed or slideback carriers have been utilised for transporting vehicles since the late 1960&#39;s. Wheel lifts were developed for transporting vehicles in the 1980&#39;s. The wheel-lift was integrated into the slideback carrier and is dependent upon the carriers articulating support structure as its operative and structural support mechanism. 
     One shortcoming of the currently available configuration is the designs limitations. Each of the carrier body assemblies for creation of a flatbed vehicle transportation truck is limited in that the design is specific to the configuration of the receiving vehicles construction. The variety of donor vehicles and imposed conflicts between each of the wide range of different truck chassis frame configurations and safety standards in the market place limit the interchangeability between product designs. This directs the carrier body manufacturer to make available a series of designs for specific or potential donor vehicles. Additionally, the balance of the distribution chain is challenged to inventory and support many varieties of form factors to support the possible donor vehicles. A single design that is adaptable to any donor vehicle is desirable. 
     A second shortcoming of the currently available configuration is the need to reinforce or modify the structure of the donor truck&#39;s chassis frame prior to mounting a non-affixed articulating type of truck body similar to the flatbed carrier assembly. Structural modifications to the donor vehicle&#39;s chassis frame can impact the vehicle&#39;s warranty, any prior government design approvals, certifications, and the like. Significant considerations need to be made prior to making any structural changes to the donor vehicle. A carrier body assembly that avoids any modifications to the donor vehicle&#39;s chassis frame is desirable. A design that can be integrated onto light and medium duty trucks is desired. 
     A third shortcoming of the currently available carrier configuration is the requirement of a long carrier body length who&#39;s structural mass is abnormally overextended by design beyond the vehicle&#39;s rear axle and suspension members during over the road transport mode, in order to achieve a respectable loading angle when the distal end of the carrier body is in contact with the ground or load receiving surface, and is longer than required to support the overall wheel base of a vehicle such as an extended pick up truck or an oversized luxury car, such as a Rolls Royce, during transport. Normally, the carrier body is required to be positioned fully retracted, thus engaging locking pins prior to transporting any vehicles. This configuration is considered overkill for the majority of smaller or medium cars and vans. These longer towing vehicles with an extended rear overhang are disproportionally balanced, are less stable, and are heavier, thus resulting in higher fuel costs. These longer towing vehicles are also less maneuverable than shorter vehicles, particularly in tight areas such as cities. A carrier body assembly that can be integrated onto a donor vehicle with a shorter overall dimension is desirable. 
     SUMMARY OF THE INVENTION 
     The basic inventive concept for a flatbed vehicle carrier. 
     A first aspect of the present invention provides a flatbed carrier assembly comprising:
         a chassis mounting platform assembly;       

     a carrier body subassembly comprising a carrier floor supported by a carrier body; 
     a slide enabling sill frame being integrated into the carrier body; 
     a carrier body intermediate subframe with a plurality of longitudinally arranged slide provisions provided in a parallel arrangement; 
     a carrier tilt and longitudinal control inner pivotal subassembly being slideably assembled to the carrier body intermediate subframe and pivotally assembled to the chassis mounting platform; 
     a carrier pivot control device extending between the carrier body intermediate subframe and the chassis mounting platform assembly; 
     a carrier body longitudinal actuator member to slideably position the carrier body subassembly along a longitudinal axis of the carrier body subassembly, the carrier body longitudinal actuator member having a first end attached to the carrier intermediate subframe and a second end attached to the carrier body subassembly; and 
     a carrier tilt and longitudinal control inner subframe motion actuator having a first end attached to the carrier tilt and longitudinal control inner pivotal subassembly and a second end attached to the carrier intermediate subframe subassembly, 
     wherein the carrier tilt and longitudinal control inner subframe motion actuator slideably positions the carrier intermediate subframe subassembly parallel to the longitudinal axis of the carrier body subassembly, wherein the sliding motion works on conjunction with the carrier pivot control device to generate a pivotal motion of the carrier intermediate subframe subassembly. 
     A second aspect of the present invention integrates a series of extrusions to form the carrier body. 
     In another aspect of the present invention, the carrier body further comprises a pivotal ramp assembly located adjacent to a loading end of the carrier body. 
     In another aspect, the pivotal ramp assembly is fabricated via a series of integrated extrusions. The extrusions utilised are preferably the same as those provided for the carrier body. 
     In another aspect, the pivotal ramp assembly is operated via a rotating cam assembly. 
     In another aspect, the pivotal ramp assembly is operated via a motive driven cable chain drive assembly. 
     In another aspect, the pivotal ramp assembly is operated via a hydraulic assembly. 
     In another aspect, the carrier drive mechanism is a hydraulic assembly. 
     In another aspect, the carrier pivotal control motion actuator is a hydraulic assembly. 
     In another aspect, a wheel lift subassembly is attached to and able to slide within the chassis mounting platform assembly. 
     In another aspect, the wheel lift comprises a lateral extension mechanism and a pivot control mechanism. 
     In another aspect, the flatbed carrier assembly is complete and independent of a vehicle trailer frame, wherein the flatbed carrier assembly can be adapted to any reasonable vehicle trailer frame. 
     Details of these and additional aspects of the present invention are presented in the detailed description of the drawings presented below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described, by way of example, with reference to the accompanying drawings, where like numerals denote like elements and in which: 
         FIG. 1  presents a top isometric exploded assembly view of the basic elements of a flatbed carrier and mounting platform assembly; 
         FIG. 2  presents a top isometric exploded assembly view of the operative elements of the flatbed carrier and mounting platform assembly of  FIG. 1 ; 
         FIG. 3  a bottom isometric exploded assembly view of the operative elements of the flatbed carrier and mounting platform assembly of  FIG. 1 ; 
         FIG. 4  presents a bottom isometric exploded assembly view of the basic elements of the flatbed carrier and mounting platform assembly of  FIG. 1 ; 
         FIG. 5  presents a bottom isometric partially assembled view of the flatbed carrier, the intermediate subassembly, and the mounting platform assembly of  FIG. 1 ; 
         FIG. 6  presents a bottom isometric fully assembled view of the flatbed carrier assembly and the intermediate subassembly integrated upon the mounting platform assembly of  FIG. 1 ; 
         FIG. 7  presents an elevation view of a carrying vehicle having a flatbed carrier assembly integrated thereon and introducing a wheel lift subassembly; 
         FIG. 8  presents an elevation view of the carrier vehicle illustrating a longitudinal motion of the carrier body; 
         FIG. 9  presents an elevation view of the carrier vehicle illustrating a rearward transfer and pivotal motion of the assembled carrier body, and assemblies; 
         FIG. 10  presents an isometric view of the operating mechanisms of the flatbed carrier assembly illustrating an initial pivotal motion of the carrier body subassemblies; 
         FIG. 11  presents an isometric view of the operating mechanisms of the flatbed carrier subassembly illustrating a continued and resultant rearward transfer and pivotal motion of the respective subassemblies; 
         FIG. 12  presents an isometric view of a carrier body, introducing an integrated pivotal ramp assembly; 
         FIG. 13  presents a side elevation view of the pivotal ramp assembly of  FIG. 12  operated via a cable chain drive assembly; 
         FIG. 14  presents a side elevation view of the pivotal ramp assembly of  FIG. 12  operated via a cam assembly; 
         FIG. 15  presents a side elevation view of a rear portion of the carrier vehicle positioned in a loading configuration; 
         FIG. 16  presents a sectional side view of the pivotal ramp assembly detailing a series of integrated extrusions; 
         FIG. 17  presents an isometric view of the operable mechanisms of the flatbed carrier assemblies and wheel lift subassembly integrated onto the carrier vehicle chassis; 
         FIG. 18  presents a top isometric exploded assembly view of the chassis mounting platform assembly and wheel lift subassembly; 
         FIG. 19  presents a top isometric view of the wheel lift subassembly assembled into the chassis mounting platform; 
         FIG. 20  presents a bottom isometric exploded assembly view of the flatbed carrier assemblies, the wheel lift assembly, the mounting platform assembly, and the carrier vehicle; and 
         FIG. 21  presents a top isometric view of the independent wheel lift assembly. 
     
    
    
     Like reference numerals refer to like parts throughout the various views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     A carrier assembly  100  is presented in  FIGS. 1 through 6 . The carrier assembly  100  comprises several subassemblies, including a carrier body subassembly  110 , a chassis mounting platform assembly  130 , a carrier intermediate subframe subassembly  150  and a carrier tilt and longitudinal control inner pivotal subassembly  170 . The carrier body subassembly  110  is fabricated having a carrier body floor assembly  116  spanning between a pair of longitudinally arranged carrier body edge rails  114 . The carrier body floor assembly  116  is fabricated of a plurality of extrusions, which will be detailed in  FIG. 16 . The carrier body floor assembly  116  is supported via a carrier body slide enabling sill frame. The carrier body slide enabling sill frame comprises a pair of carrier body sill frame channels  118  disposed upon an underside of the carrier body floor assembly  116 . The carrier body sill frame channels  118  are preferably fabricated of a pair of “C” or “L” shaped channels attached to the carrier body subassembly  110  along a longitudinal axis of the carrier body subassembly  110 . The carrier body sill frame channels  118  are spaced to ride along the outer edges of the carrier intermediate subframe subassembly  150 . 
     The chassis mounting platform assembly  130  is fabricated having a pair of mounting platform rail and chassis reinforcement members  132  designed to be directly or indirectly attached to a vehicle frame ( 220  of  FIG. 7 ). A headboard socket  125  and reinforced mounting platform attachment device  134  is integrated at a cab end of each mounting platform rail and chassis reinforcement member  132 . The headboard socket  125  and reinforced mounting platform attachment device  134  reinforces the attachment and rigidity of the mounting platform rail and chassis reinforcement member  132 . An independent wheel lift subassembly support cross member  140  is provided at a lift end of the chassis mounting platform assembly  130 . A similar cross member (not shown) can be assembled to the chassis mounting platform assembly  130 , spanning between the cab ends of the pair of mounting platform rail and chassis reinforcement members  132 . The cross members also provide stiffness to the chassis mounting platform assembly  130 , as well as an additional regions for mounting the chassis mounting platform assembly  130  to the vehicle frame or mounting of other subassemblies. A pivot control plate  136  is disposed upon each of the mounting platform rail and chassis reinforcement members  132 . The pivot control plates  136  extend downward providing a reasonable pivot location for a carrier pivotal control device  154 . A mounting platform pivot mating interface  137  of the pivot control plate  136  is provided for receiving a carrier pivot mating interface  156  disposed at a first end of the carrier pivotal control device  154 . It is understood the mounting platform pivot mating interface  137  can be of any form factor and provided at any reasonable location to achieve the desired mechanics of the system. A pair of integrated wheel lift fore/aft slide channels  187  is provided for receiving a wheel lift subassembly ( 180  of  FIG. 7 ). A pair of taillight subassemblies  142  can be integrated at the loading end of the chassis mounting platform assembly  130 . It is understood that tail light subassembly  142  can be assembled to the loading end of the chassis mounting platform assembly  130  (as illustrated), the carrier body subassembly  110 , or any other reasonable rearward location. 
     The carrier intermediate subframe subassembly  150  is fabricated of a pair of carrier intermediate subframe rails  152  disposed in a parallel arrangement. A carrier tilt and longitudinal control inner subframe slide channel  148  is attached to the interior side of each of the carrier intermediate subframe rails  152  for slideably receiving the carrier tilt and longitudinal control inner pivotal subframe  172 . At least one carrier intermediate subframe cross member  153  is assembled attaching the carrier intermediate subframe rails  152  in order to maintain the carrier intermediate subframe rails  152  in a parallel arrangement. The carrier pivotal control device  154  is pivotally attached to the carrier intermediate subframe subassembly  150  at a carrier second pivot interface  158 , wherein the pivot location is located proximate the cab end of the carrier intermediate subframe subassembly  150 . A carrier body longitudinal actuator member  160  is provided having a first end attached to the cab end of the carrier intermediate subframe subassembly  150  via a carrier body actuator mounting and pivot bracket  162 , as illustrated or by other means. A second end of the carrier body longitudinal actuator member  160  is attached to the carrier body subassembly  110 . The carrier intermediate subframe rails  152  preferably include a “C” channel attached along an interior surface, the “C” channels being referred to as a carrier tilt and longitudinal control inner subframe slide channel  148  as illustrated for slideably receiving the carrier tilt and longitudinal control inner pivotal subassembly  170 . Bearing strips would be provided between the sliding interfaces, including between the carrier body sill frame channels  118  and carrier tilt and longitudinal control inner subframe slide channels  148  as well as between other sliding interfaces. 
     The carrier tilt and longitudinal control inner pivotal subassembly  170  is fabricated having an inner pivotal tilt and longitudinal control motion actuator  176  having a first end attached to a feature of the carrier tilt and longitudinal control inner pivotal subassembly  170 . A second end of the inner pivotal tilt and longitudinal control motion actuator  176  is attached to a carrier intermediate subframe rear cross member  174 . The carrier intermediate subframe rear cross member  174  is secured to the loading end of the carrier intermediate subframe subassembly  150 . A carrier tilt and longitudinal control inner subframe pivot  119  is provided, preferably located proximate a loading end of the carrier tilt and longitudinal control inner pivotal subassembly  170 . The carrier tilt and longitudinal control inner subframe pivot  119  is assembled to a mating member disposed upon a rear portion of the chassis mounting platform assembly  130 , providing a means for the carrier tilt and longitudinal control inner pivotal subassembly  170 , and respectively the carrier intermediate subframe subassembly  150  to travel and pivot there about. 
     The carrier tilt and longitudinal control inner subassembly  170  slideably engages with carrier intermediate subframe subassembly  150 . In the preferred embodiment, the carrier tilt and longitudinal control inner pivotal subframe  172  is slideably inserted between the pair of inner subframe fore/aft slide channels  148 , with bearing strips provided therebetween. The carrier tilt and longitudinal control inner pivotal subassembly  170  pivotally engages with the chassis mounting platform assembly  130  proximate the loading end of the chassis mounting platform assembly  130  via the carrier tilt and longitudinal control inner subframe pivot  119 . 
     An optional, but preferred cab protector cage assembly  120  is assembled to a cab end of the chassis mounting platform assembly  130 , providing a barrier between objects placed onto the carrier body subassembly  110  and a vehicle cab ( 210  of  FIG. 8 ). The cab protector cage assembly  120  comprises a cab protector frame  122  having a series of horizontal and vertical dividing members within the interior defined by the cab protector frame  122 . A pair of cab protector mounting interface  124  extends downward from the cab protector frame  122  for attaching the cab protector cage assembly  120  to the chassis mounting platform assembly  130 . A cab protector mount receiver  125  can be provided at the cab end of each of the mounting platform rail and chassis reinforcement member  132  for receiving a cab protector mounting interface  124 . This interchangeable interface allows the installer to insert a cab protector cage assembly  120  designed specifically to compliment the size and shape of the cab  210  of the donor vehicle. This provides for a variety of alternate components the installer selects to inventory. 
     The carrier operates in accordance with the following motions: 
     Operation of the carrier body longitudinal actuator member  160  slides the carrier body subassembly  110  forward and aft, tracking along the carrier body sill frame channel  118  to carrier intermediate subframe rail  152  interface. In the illustrated exemplary embodiment, extending the carrier body longitudinal actuator member  160  moves the carrier body subassembly  110  rearward. Contracting the carrier body longitudinal actuator member  160  moves the carrier body subassembly  110  forward. Operation of the inner pivotal tilt and longitudinal control motion actuator  176  causes the carrier intermediate subframe subassembly  150  to exert a force upon the carrier second pivot interface  158 , the force being applied towards the mounting platform pivot mating interface  137 . The carrier tilt and longitudinal control inner pivotal subassembly  170  tracks within the carrier tilt and longitudinal control inner subframe slide channels  148  to carrier tilt and longitudinal control inner pivotal subframe  172  interface. The carrier pivotal control device  154  provides a carrier pivotal control which causes the carrier intermediate subframe subassembly  150  to pivot up, over, and rearward while sliding along the carrier tilt and longitudinal control inner pivotal subassembly  170  and pivoting about the carrier tilt and longitudinal control inner subframe pivot  119 . In the preferred embodiment, the carrier pivotal control device  154  is a fixed beam. It is understood that the carrier pivotal control device  154  can be mechanically or otherwise adjustable. 
     An exemplary carrier vehicle  200  having a carrier assembly  100  integrated thereon is illustrated in  FIGS. 7 through 9 . The carrier vehicle  200  includes a cab  210  assembled upon a vehicle frame  220 . Although not identified, the carrier vehicle  200  additionally includes commonly known components such as wheels and tires, an engine and drive train, suspension, steering components, and the like. The chassis mounting platform assembly  130  is assembled to the vehicle frame  220 . 
     An independent wheel lift subassembly  180  is slideably assembled within the wheel lift fore/aft slide channels  187  interface of the chassis mounting platform assembly  130 , such to slide fore and aft. The independent wheel lift subassembly  180  comprises an independent wheel lift extendible inner boom  184  with an independent wheel lift extensible inner boom motive actuator  198  being slideably assembled within an independent wheel lift pivotal lifting boom assembly  182 . An independent wheel lift rotational cross bar  186  is disposed upon a distal end of the independent wheel lift extendible inner boom  184 . An independent wheel lift pivotal boom lifting actuator  188  is connected to wheel lift pivot actuator connecting bracket  168  having a first end which is affixed to wheel lift pivot actuator connecting bracket  168  mounted upon a wheel lift cross member  167  and second end attached to a pivot actuator boom bracket  183  which is assembled to the independent wheel lift pivotal lifting boom assembly  182 . The fore/aft repositioning of the independent wheel lift between a retracted stored position and an extended towing position is accomplished by means of an independent wheel lift fore/aft motion actuator  185  having a first end attached to the independent wheel lift support cross member  140  and a second end attached to wheel lift extension actuator assembly joint  165  of the wheel lift pivot actuator connecting bracket  168 . The independent wheel lift pivotal lifting boom assembly  182  is pivotally attached to the independent wheel lift slide rail members  178  via a pivotal boom transverse support member  189  via independent wheel lift lifting boom trunion pivot  196 . 
     General operation of the carrier assembly  100  is illustrated in  FIGS. 8 and 9 . Respective details of the functional structures are exposed in  FIGS. 10 and 11 . The carrier body subassembly  110  slides aft in accordance with a rearward motion  190 , as illustrated in  FIG. 8 . This motion is driven by the carrier body longitudinal actuator member  160 . A motion actuator rod  164  extends and retracts from within a cylinder body of the carrier body longitudinal actuator member  160 . The distal end of the motion actuator rod  164  is attached to the carrier body subassembly  110 . The angle of the carrier body subassembly  110  is controlled via a rotation in accordance with a pivotal motion  192  ( FIG. 9 ). The carrier intermediate subframe rail  152  is moved rearward via the inner pivotal tilt and longitudinal control motion actuator  176 . As the carrier intermediate subframe rail  152  attempts to move rearward, a torque is generated against the carrier pivotal control device  154  causing the carrier intermediate subframe rail  152  to consequently travel up, over, and rearwardly while traveling via carrier tilt and longitudinal control inner pivotal subassembly  170  and pivoting about the carrier tilt and longitudinal control inner subframe pivot  119 . The mounting platform pivot mating interface  137  must be positioned at a distance from the longitudinal axis of motion of the carrier intermediate subframe rail  152  in order to generate the necessary torque to pivot the carrier intermediate subframe rail  152 . If the mounting platform pivot mating interface  137  were aligned with the longitudinal axis of motion of the carrier intermediate subframe rail  152 , the subassembly would tend to bind upon attempted powered operation of the inner pivotal tilt and longitudinal control motion actuator  176 . The carrier body subassembly  110  can be additionally adjusted along an incline until the loading end contacts the ground via a carrier body travel  194 . The carrier body subassembly  110  moves along a sliding interface formed between the carrier body sill frame channel  118  and the carrier intermediate subframe rail  152 . In this configuration, a vehicle may be driven upon the body, or alternately, winched thereon. A winch assembly may be affixed to the front or other portion of the carrier body subassembly  110 . 
     A carrier body internal pivotal ramp subassembly  250  can be optionally integrated into the carrier body subassembly  110 , as described by the exemplary illustrations presented in  FIGS. 12 through 16 . The carrier body internal pivotal ramp subassembly  250  functions as an independently operated subassembly. The carrier body internal pivotal ramp subassembly  250  comprises an internal ramp pivot  260  integrated into a carrier ramp assembly  252 . The carrier ramp assembly  252  is fabricated of a series of interlocking floor extrusions  264  and a pivot floor member  262  assembled at the loading end of the carrier ramp assembly  252 . Each of the interlocking floor extrusions  264  is formed to include an engagement interface receiver  269  along a first edge and an engagement interface hook  268  along a second edge. The engagement interface receiver  269  engages with the engagement interface hook  268  forming a locking floor engagement interface  266  along at least a portion of the length of the interlocking floor extrusion  264 . The carrier body floor assembly  116  can be fabricated of a similar series of interlocking floor extrusions  264  of the carrier ramp assembly  252 . An optional end cap extrusion (not shown, but well understood) can be provided on the exposed (loading) end of the carrier body floor assembly  116  and the cab end of the carrier ramp assembly  252 . A pivotal floor side support and track member  272  can be assembled along each edge of the carrier ramp assembly  252 , providing additional rigidity to the carrier ramp assembly  252 . 
     A carrier body approach plate member  254  is provided aft of the carrier ramp assembly  252 . The carrier body internal pivotal ramp subassembly  250  is pivotally attached to the carrier body edge rail  114  of the carrier body subassembly  110  via an internal ramp pivot  260 . A pivotal control assembly is provided between a cab end of the carrier body internal pivotal ramp subassembly  250  and a respective location on the carrier body edge rail  114 , as illustrated, or carrier body sill frame channel  118 . The disclosure presents two exemplary embodiments of the pivotal control assembly. The first exemplary embodiment is presented in  FIG. 13 , utilizing an internal pivot ramp control cable chain  282 , which is secured to the carrier body internal pivotal ramp subassembly  250  via a cable chain anchor  284 , redirected over a cable chain redirecting pulley  286  and operated via an internal pivot ramp drive apparatus  280 . A pressurized tensioning device  270  can be provided as an alternate embodiment or as a supplemental support to the cable chain embodiment. A second exemplary embodiment is presented in  FIG. 14 , utilizing a ramp pivot cam  290 . A cam actuator  292  rotates the ramp pivot cam  290  via a cam rotation  294  about a body pivot interface  296  to raise and lower the carrier body internal pivotal ramp subassembly  250  via a ramp pivot interface  298 . The ramp pivot interface  298  is preferably a pinned bearing block allowing for dimensional adjustments to avoid any binding along pivotal floor side support and track member  272 . 
     The operator would direct the carrier body subassembly  110  into an angled, loading configuration, positioning the carrier body approach plate member  254  in contact with the supporting surface  199 . The operator would then rotate the carrier body internal pivotal ramp subassembly  250 , as described above, into a horizontal, loading configuration as illustrated in  FIG. 15 . This feature allows for damage free loading of vehicles having a low front valance or other low feature located forward of the tires. 
     An independent wheel lift subassembly  180  can be integrated onto the carrier vehicle  200  as best shown in  FIGS. 7-9  and  17 - 21 . The independent wheel lift subassembly  180  is a complete subassembly, having an independent wheel lift pivotal lifting boom assembly  182  pivotally attached to an independent wheel lift slide enabling subframe  181  via a pivotal boom transverse support member  189 . At least one independent wheel lift pivotal boom lifting actuator  188  provides a drive mechanism to pivot the independent wheel lift pivotal lifting boom assembly  182  via the pivotal boom transverse support member  189 . In the exemplary embodiment, independent wheel lift pivotal lifting boom assembly  182  is affixed to the pivotal boom transverse support member  189  and rotates about the independent wheel lift lifting boom trunion pivot  196 . When the independent wheel lift pivotal boom lifting actuator  188  extends, the independent wheel lift pivotal lifting boom assembly  182  pivots downward towards a loading configuration. When the independent wheel lift pivotal boom lifting actuator  188  contracts, the independent wheel lift pivotal lifting boom assembly  182  pivots upward, lifting the towed vehicle into a transporting configuration. The independent wheel lift extendible inner boom  184  is slideably assembled within the independent wheel lift pivotal lifting boom assembly  182  and horizontally positioned via an independent wheel lift extensible inner boom motive actuator  198 . The actuator  198  (not shown, but well understood) is preferably a dual action, hydraulic piston assembly. An independent wheel lift rotational cross bar  186  is provided along a distal end of the independent wheel lift extendible inner boom  184 . The independent wheel lift rotational cross bar  186  is preferably configured to be perpendicular to the independent wheel lift extendible inner boom  184  and parallel to the supporting surface  199 . The independent wheel lift rotational cross bar  186  can include features commonly associated with presently available wheel lifts, such as self-actuating wheel grabbers. The independent wheel lift rotational cross bar  186  can be connectively assembled to the independent wheel lift extendible inner boom  184 , allowing the owner/operator to exchange the independent wheel lift rotational cross bar  186  with various specialized automotive vehicle wheel retaining devices commonly available through third party automotive towing equipment manufacturers or suppliers. 
     When the independent wheel lift subassembly  180  is in a retracted, stored configuration, the independent wheel lift rotational cross bar  186  acts as an under ride, protective device member upon collision with other vehicles following the carrier vehicle  200 . Since the independent wheel lift subassembly  180  operates independently from the carrier body subassembly  110 , and its adjoining subassemblies  170  and  150 , the independent wheel lift rotational cross bar  186  can be positioned against the supporting surface  199  when loading vehicles onto the carrier body subassembly  110 . This increases the stability of the carrier vehicle  200  during loading/unloading of vehicles from the carrier body subassembly  110 . 
     The independent wheel lift slide enabling subframe  181  is within the wheel lift fore/aft slide channel  187  of the chassis mounting platform assembly  130 . The independent wheel lift fore/aft motion actuator  185  is integrated into the independent wheel lift subassembly  180 , having a first end attached to a member of the chassis mounting platform assembly  130  and a second end attached to the independent wheel lift slide enabling subframe  181 . In the exemplary embodiment, the first end of the independent wheel lift fore/aft motion actuator  185  is attached to the independent wheel lift subassembly support cross member  140  of the chassis mounting platform assembly  130 . The second end of the independent wheel lift fore/aft motion actuator  185  is attached to the wheel lift pivot actuator connecting bracket  168  which is affixed to wheel lift cross member  167  of the independent wheel lift slide enabling subframe  181 . The independent wheel lift fore/aft motion actuator  185  extends and contracts to position the independent wheel lift subassembly  180  within the respective wheel lift fore/aft slide channels  187  of the chassis mounting platform assembly  130  between a retracted stowed position and a rearward, towing position. 
     The present invention provides several advantages over the existing art in the industry. The carrier assembly  100  is designed as a complete subassembly, allowing for its installation onto any reasonably sized truck chassis frame  220 . Adaptors  222 ,  224  ( FIG. 20 ) can be provided for mounting and securing the chassis mounting platform assembly  130  onto a variety of vehicle chassis frames  220  of varying dimensions. This provides for a standardized carrier assembly  100  and mounting means that will accommodate a variety of vehicle chassis without changes or compromises of the carrier vehicle. The carrier body assembly  100  need only to be of sufficient length to accommodate the overall wheel base spread of the transported vehicle, without concern of a rearward over extended body or platform, simply to provide a longer ramp in order to secure a reduced loading angle during loading/unloading. The new inventive matter with a shortened carrier body assembly, and accompanying subassemblies, with ability to be pivotally postured and transferred rearward upon initiation of its operative sequence through its intermediate connecting subassembly  150  provides for the same resultant decreased loading angle, which is then further enhanced by the downward deployment of the inclusive carrier body pivotal ramp subassembly  250 . 
     The angle of the carrier assembly  100  is achieved via a single actuator motion, via the carrier tilt and longitudinal control inner subframe motion actuator  176 . This controlled action of carrier assembly  100  and the sliding interface activity between the carrier intermediate subframe subassembly  150  and the carrier tilt and longitudinal control inner pivotal subassembly  170 , minimizes operator error resulting from incorrect rotation of the carrier body subassembly  110 . Integrating a carrier body internal pivotal ramp subassembly  250  within allows the operator to further optimize a transition for loading of a vehicle to be carried between the supporting surface  199  and the angled carrier body floor assembly  116 , thus providing loading without abrasion or damage to a vehicle having a low front or rear clearance. 
     The assemblage of the carrier body floor assembly  116  utilising a series of interlocking extrusions, such as the interlocking floor extrusion  264 , which provides a rigid structure with minimal framing and fabrication cost. 
     It is understood that lighting would be integrated onto the carrier assembly  100  to ensure the lighting complies with the respective state and federal regulations for the carrier vehicle  200  as converted. This would accommodate conversions using light and medium duty trucks into the carrier vehicle  200 . 
     Since many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalence.