Abstract:
A truck tractor and removable body unit system selectively configurable as a tractor and freight box or an articulated truck-trailer combination includes a truck tractor having a frame supporting a drive axle and a steer axle with a fifth wheel mounted on the frame, and a body unit having a body mounted on a frame, the frame supported by a wheeled axle and having a king pin for releasably engaging the fifth wheel on the truck tractor. The body unit includes a coupling mechanism for releasably coupling the truck tractor frame to constrain lateral movement between the truck tractor and the body unit while allowing relative vertical pivoting movement between the truck tractor and body unit about the king pin and fifth wheel. An adjustable spring mounted to one of the truck tractor and body unit to act between the truck tractor frame and the body unit frame to adjust a loading between the truck tractor frame and body unit.

Description:
FIELD OF THE INVENTION 
     The invention relates to vehicles having removable bodies adapting the vehicle for different uses. More particularly, the invention relates to a vehicle power unit, such as a truck tractor, and a removable body unit allowing for the body unit carried by the truck tractor frame or coupled to the truck tractor frame by a fifth wheel. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     For operation on the U.S. interstate highway system, commercial vehicle configurations must comply with federal size and weight regulations (See, Code of Federal Regulations, Title 23, Part 658, Truck Size and Weight). Currently there are two common, federally-compliant tractor truck-trailer combinations: a tractor with a single 48 to 53 foot semi-trailer; and a tractor with a tandem of two, coupled, 28 foot semi-trailers. In the tandem semi-trailer-trailer arrangement, the second trailer is typically connected via a kingpin to a fifth wheel carried on an added convertor dolly which, in turn, is connected to the first trailer via a drawbar/pintle hook. 
     Some LCV (Long Combination Vehicle) configurations are permitted in a few Western US states. Examples of LCV configurations include a tandem of two 48 foot or longer trailers, a tandem of a 48 foot or longer trailer and a coupled 28 foot trailer, and a set of three coupled 28 foot trailers. However, LCV arrangements are not permitted under federal regulations and therefore are restricted to specific routes or areas of operation. 
     There are commonly used fixed add-on van bodies (called dromedary boxes) which may be mounted on the truck tractor frame and used to haul limited extra freight. 
     Many loads are volume sensitive and “cube-out”, meaning the trailer volume is filled before the trailer weight limit is reached. This type of load is less efficient and generates unnecessary cost to the shipper (more trips are needed) and to the environment as more fuel is burned for the extra trips. 
     There is thus a need in the transportation industry to increase volume in truck tractor-trailer combinations within federal size and weight regulations. There is a need in the transportation industry to maximize freight loads (for both volume and weight). Resolving these needs will lower shipping costs, reduce fuel consumption by allowing fewer trips to move goods, and reduce highway congestion by having fewer trucks on the road. 
     The invention is directed to a novel truck tractor and trailer combination that fills this need. The invention comprises individual truck tractor and trailer components that in combination improve volume efficiency while complying with federal highway regulations and preserving the adaptability of the individual components. 
     The invention includes a van body or body unit mounted on a frame and having an axle assembly with a set of wheels on the frame extended behind the body. A coupling apparatus integrally mounts the van body to a truck tractor so as to form a non-horizontally articulated vehicle. A fifth wheel is provided at the rear end of the van body frame for connecting a conventional semi-trailer. Thus, a truck tractor and van body combination can selectively pull a semi-trailer. 
     Alternatively, the van body can be articulatedly coupled to the truck tractor at a fifth wheel on the truck tractor, thus forming a truck tractor-trailer combination. 
     According to the invention, a truck tractor and removable body unit system selectively configurable as a tractor and freight box combination or as an articulated truck tractor-trailer combination includes a truck tractor having a frame supported on a drive axle and a steer axle and having a fifth wheel mounted on the frame, and a body unit having a body mounted on a frame, the frame supported on an axle/wheel assembly and having a king pin for releasably engaging a fifth wheel, a coupling mechanism for releasably coupling the truck tractor frame and the body unit frame allowing relative vertical pivoting movement and constraining relative lateral movement between the truck tractor and body unit about the king pin and fifth wheel, the coupling mechanism releasably coupling a rear of the truck tractor frame to a location on the body unit spaced from the king pin, and an adjustable spring (e.g., an air spring) mounted to one of the truck tractor and body unit to act between the truck tractor frame and the body unit frame to adjust a loading between the truck tractor frame and body unit. 
     According to an aspect of the invention, the coupling mechanism includes a pair of laterally extending pins mounted to opposite sides of one of the truck tractor frame and body unit frame, and a pair of coupling plates mounted to opposite sides of the other of the truck tractor frame and body unit, the coupling plates each including a vertically oriented slot shaped to accept a pin and allow relative vertical movement of the pin in the slot. 
     According to another aspect of the invention, a trailing portion of the body unit frame extends beyond an end of the body, the axle assembly being mounted on the extended frame portion. A fifth wheel may be mounted on the trailing portion of the body unit frame for coupling and supporting a semi-trailer. 
     According to yet another aspect of the invention, the trailing portion of the body unit frame is movable between an extended position in which the axle assembly is positioned beyond the end of the body and a retracted position in which the axle assembly is disposed beneath the body. The retracted position of the axle assembly allows the body to be backed to a loading dock to facilitate loading and unloading. The body unit frame may include main frame rails having a profile defining a channel and the trailing portion of the body unit frame includes frame rails slidably nested in the channel of the body unit main frame rails. 
     According to the invention, the fifth wheel on the truck tractor frame is mounted for sliding for selectively positioning the fifth wheel on the truck tractor frame in a forward position (i.e., adjacent the truck tractor cab) and a rear position (i.e., adjacent a rear of the truck tractor frame). 
     According to another aspect of the invention, the axle assembly of the body unit is a steerable axle, and may be a self-steering axle or powered steering axle. According to another aspect, the steerable axle may be convertible between steerable and fixed axle functions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood with reference to the following detailed description read in conjunction with the appended drawings, in which: 
         FIG. 1  is an illustrative side view of a truck tractor and body unit system in accordance with the invention configured as a truck tractor coupled with a semi-trailer. 
         FIG. 2  is an illustrative side view of a truck tractor and body unit in accordance with the invention configured as a tractor and freight box combination; 
         FIG. 3  is an illustrative side view of a truck tractor and body unit in accordance with the invention configured as a tractor-trailer combination; 
         FIG. 4  is a side view of a truck tractor in accordance with an embodiment of the invention; 
         FIG. 5  is a side view of a body unit in accordance with an embodiment of the invention; 
         FIG. 6  is a side view of an end portion of a power unit frame in accordance with an embodiment of the invention; 
         FIG. 7  is a section view of the end portion of  FIG. 6  shown with the body unit to illustrate a load distribution device; 
         FIG. 8  is a top view of the end portion of the power unit frame shown in  FIG. 6 ; 
         FIG. 9  is a side view showing a coupling mechanism for the power unit and body unit; 
         FIG. 10  is a top view of the coupling mechanism of  FIG. 9 ; 
         FIG. 11  is a side view of an alternative coupling mechanism for the power unit and body unit; 
         FIG. 12  is a top view of the coupling mechanism of  FIG. 11 ; and, 
         FIG. 13  is an end view of a sliding frame rail of the body unit. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 ,  2  and  3  illustrate alternative arrangements of a truck tractor and removable body unit system in accordance with the invention. The arrangement in  FIG. 1  shows a truck tractor  10 , also referred to here as the power unit, with a body unit  12  coupled to the truck tractor for no horizontal articulation and a semi-trailer  20  coupled to the body unit extended frame  14 . As described below and shown in  FIG. 1  and  FIG. 2 , the body unit  12  is coupled to the power unit  10  at a fifth wheel  22  on the power unit and at a rear end of the power unit frame  11  so that the body unit  12  is constrained against lateral movement, or articulation, relative to the truck tractor. 
     In  FIG. 1 , a frame  14  of the body unit  12  extends beyond a rear of the body  13  and is supported by an axle assembly  16 . The axle assembly  16  includes a conventional non-driven axle and suspension components. The frame  14  carries a fifth wheel  18  to which may be coupled a semi-trailer  20 , as seen in  FIG. 1 . In this embodiment, the body unit is a  28  foot long unit, and the semi-trailer  20  is a  53  foot trailer. 
     In the embodiment of  FIG. 2 , the power unit  10  and body unit  12  form a non-horizontally articulated unit, but the frame  14  of the body unit  12  is retracted so that the axle assembly  16  is beneath a rear portion of the body  13 . The two positions of the frame  14  and axle assembly  16  are shown in  FIG. 5 . The details of the extendible and retractable frame  14  are described below in connection with  FIG. 13 . 
     Referring to  FIG. 4 , the power unit  10  in accordance with the illustrated embodiment of the invention is an extended wheelbase 4×2 (single drive axle) tractor with a fifth wheel  22  on a sliding fifth wheel support  24 . The sliding fifth wheel support  24  of the invention is longer than a conventional sliding fifth wheel support to allow placement of the fifth wheel closer to the cab than is typical. The forward position  26  of the fifth wheel  22  is useful for the non-horizontally articulated coupling shown in  FIG. 1  and  FIG. 2 . Sliding fifth wheel supports allowing the selected movement and positioning of a fifth wheel on a truck tractor frame are known, and will not be described here. The fifth wheel  22  in the rear position  28  on the truck tractor frame allows the power unit  10  to be used as a traditional tractor pulling a semi-trailer, which may be the body unit  12 , as shown in  FIG. 3 , or another semi-trailer. 
     Referring to  FIG. 5 , the body unit  12  has dimensions similar to that of a short (28 foot) semi-trailer, that is, in height, length and width. The body and floor have the same construction as a standard semi-trailer, which will not be described here as this is within the ordinary skill in the art. The body unit  12  includes a king pin  30  near a front end of the body  13  for coupling with the fifth wheel  22 . A coupling frame  60  is spaced rearward of the king pin  30  and allows the body unit  12  to couple to the power unit in the non-horizontally articulated configuration. The coupling frame  60  is described in more detail in conjunction with  FIGS. 9-12 , below. 
       FIG. 6  shows a side view of an end of the truck tractor frame  11  and  FIG. 7  shows a schematic view of the end of the truck tractor frame and the body unit body floor to illustrate a load distribution device  50 . The load distribution device is not shown in  FIG. 6  for clarity of the drawing.  FIG. 8  is a top view of the frame  11  of  FIG. 6 . The frame  11  may have a conventional suspension  34  for the axle assembly  16 , including an arm  35  to which the axle is mounted extending rearward from a hanger bracket  36  and an air spring  37  and a damper  38  mounted between the arm  35  and frame rail  40 . 
     The frame  11  has two connecting pins at the rear sides of the frame, a left pin  44  mounted on the left rail  40  and a right pin  45  mounted on right rail  42  (shown in  FIG. 8 ) for coupling with the body unit  12 . Left and right are as viewed from the rear of the frame toward the front. As explained below in connection with  FIGS. 9 and 10 , the pins  40 ,  42  serve as positioning guides and vertical articulation limiters for coupling the truck tractor frame  11  to the body unit  12 . The pins  44 ,  45  are members similar to a king pin, having a shaft and a flanged end. 
     The truck tractor frame  11  includes an end cross member  46  connecting the ends of the frame rails  40 ,  42  to provide rigidity. A slanted upper surface  48  on the rear of the frame rails  40 ,  42  assists as a positioning guide when the body unit  12  is docked onto the frame  11 , providing a surface for the front of the body unit  12  to slide over if the relative heights are not in alignment. 
     According to the invention, a load distribution device  50 , illustrated in  FIG. 7  and  FIG. 8 , is disposed vertically between the truck tractor frame  11  and the body unit  12 . The load distribution device  50  helps distribute the load of the body unit between the rear of the power unit frame  11  and the fifth wheel  22 . The load distribution device  50  may be a pneumatic spring, as illustrated, or alternatively, a mechanical spring or hydraulic spring. If the device  50  is either pneumatic or hydraulic, the device pressure can be altered to change the load distribution on the power unit chassis to help prevent overload of the power unit&#39;s steer axle system and the drive axle system. A pneumatic or hydraulic spring may be connected to the pneumatic or hydraulic system of the power unit. When deactivated, the device  50  deflates or empties, lowering its height (shown in broken lines in  FIG. 7 ), which allows clearance for the body unit  12  to move over it. The deactivated state is useful for coupling and uncoupling the body unit to the power unit. 
     The load distribution device  50  may be seated on a cross member  52  mounted between the frame rails  40 ,  42  on the power unit  14  frame. A cup  53  or recess provided on the body unit  12  receives the top or crown  51  of the spring  50 . The load distribution device  50  is shown mounted on the truck tractor frame  11 , however, it may alternatively be mounted on the body unit, and appropriate air or hydraulic connections made with the truck tractor systems. 
     Because of the length added by the body unit frame  14  when extended (i.e., the position seen in  FIG. 1  and  FIG. 5 ), there is a need in the power unit  10  to body unit  12  coupling for restricted articulation in the vertical (“Z”) direction to navigate some terrain conditions (e.g., traversing a raised railroad crossing or backing to a loading dock that has a storm drainage dip).  FIG. 9  shows a simplified side view from the left and  FIG. 10  shows a simplified top view of the power unit  12  frame  11  and body unit  12  coupling frame  60 . The power unit frame  11  includes a wear plate  54 , preferably made of stainless steel, mounted on each rear corner (only the left rear corner is shown in  FIGS. 9 and 10 ). The wear plate  54  is shaped with a chamfered face  55  to assist in aligning the power unit frame  11  and the body unit coupling frame  60 . The pin  44  is mounted to a laterally facing surface  56  of the wear plate forward of the chamfered face  55 . 
     The body unit coupling frame  60  includes a bumper  62  mounted at the same angle as the chamfered face  55  of the wear plate  54  to abut the chamfered face  55  when the coupling frame is coupled to the power unit frame  11 . The bumper  62  may be formed of an elastomeric material such as rubber or the like. An alignment jaw  70  is mounted on the coupling frame  60  to extend forward from the coupling frame on a lateral outer side of the coupling frame. The alignment jaw  70  includes a vertical slot  72  to receive the pin  44 . The vertical slot  72  allows the pin, and accordingly, the power unit frame  11 , to move vertically relative to the coupling frame  60  and body unit  12 . An alignment cap  74  is provided laterally outward of the alignment jaw  70  to aid in aligning the power unit frame  11  to the coupling frame  60  during coupling. The head of the pin  44  is captured between the alignment jaw  70  and the alignment cap  74 . It should be understood that the chamfered faces  55  on each side of the frame  11  define a tapered end that couples with the two bumpers  62  in the coupling frame  60 . The tapered end abutment with the bumpers and the pins  44 ,  45  coupling to the alignment jaws on the left and right sides of the body unit coupling frame  60  help prevent relative lateral movement of the power unit frame and body unit frame. 
     An alternative arrangement of the coupling between the power unit  10  and body unit  12  allowing vertical pivoting movement is shown in the side view of  FIG. 11  and top view of  FIG. 12 . The power unit frame  11  in this embodiment includes a pneumatic cylinder  80  to drive a lock pin  82  through a hole in the frame  11  to engage a slot  84  formed in an alignment jaw or coupling frame rail  86  of the body unit  12 . The coupling frame rail  86  is disposed to overlap the frame  11  of the power unit, which provides constraint to relative lateral movement of the power unit  10  and body unit  12 . In the illustrated embodiment, the coupling frame rail  86  is a piece mounted laterally outward on the main frame rail  88  of the body unit  12 . When coupled, the main frame rail  88  of the body unit abuts the frame rail  40  of the power unit and the pneumatic cylinder drives the lock pin  82  into the slot  84 . The alignment jaw or coupling frame rail  86  includes a flared end  90  to assist in aligning the body unit  12  to the power unit  10 . Alternatively, the body unit main frame rail  88  may be disposed to overlap the frame rail  40  of the power unit itself to provide an alignment jaw. According to this embodiment, the body unit king pin  30  is engaged with the fifth wheel  22  of the power unit  10 , as described above. 
     The body unit frame also provides structure for the extending and retracting the frame from the end of the body unit, that is, between the positions shown in  FIG. 1  and  FIG. 2 . This allows the wheel/axle assembly  16  and fifth wheel  18  to be positioned under the body unit or extended rearward of the body unit to couple with a semi-trailer.  FIG. 13  shows an end view of an extendible frame  14 . A sliding frame  14  includes two frame “G” profile sections  100 ,  102  for each frame rail. The sections  100 ,  102  are nested with one section  100  inside the other section  102  and the short vertical webs  104 ,  106  engaging the long vertical web  108 ,  110  of the other section. Alternatively, the sliding frame rail could include two “C” channels arranged back to back with a bearing mechanism, for example, a collar, connecting them. A locking device, for example, the Quick-Draw pneumatic pin-pull mechanism available from Hendrickson International Corporation of Canton, Ohio, may be used to secure the sliding frame rail in the selected position. 
     As will be understood by those skilled in the art, one of the sliding sections will be attached to the body unit sub-frame and the other to the axle assembly  16 . 
     The axle assembly  16  has additional features to facilitate its modes of operation. Because the body unit  12  is connected as a non-horizontally articulated body to the power unit, the axle assembly  16  is configured as a steerable axle for maneuverability of the combination as well as to minimize the tire scrubbing due to the long distance between the power unit&#39;s drive axle and the body unit axle  16  when the body unit frame  14  is in the extended position. This steering capability may be accomplished by either a “self-steer” configuration (using axle caster and stabilizer shock absorbers to facilitate the tires&#39; return to the straight ahead position) or a hydraulic or electric power steering system connected to the power unit&#39;s steering system. For example, a self-steering system such as the Composilite or the Paralift steerable suspension systems from Hendrickson International Corporation of Canton, Ohio, may be used. 
     The axle assembly  16  also has the ability to lock the position of the tires in the straight ahead position for when the body unit is standing alone (separated from the power unit) and when it used as a semi-trailer. The axle assembly may include actuator pins on the ends on the axle to lock the axle in the straight ahead position. The actuator pins may be manually set, or alternatively, activated electronically, as part of the vehicle&#39;s operational logic, when the vehicle reaches a certain speed on the highway to enhance the vehicle combination handling stability. 
     The axle assembly  16  also includes the ability to reverse the axle caster (angle of the axle in the direction of travel of the vehicle). When in steering mode, the axle caster provides the geometry that keeps the axle tires in the straight ahead position and also facilitates the return to straight ahead position of the tires after a vehicle turning maneuver. When the power unit and body unit as a tractor and freight box configuration backs up the axle assembly  16  must reverse caster or the tires will severely rotate to one side or the other. Allowing this to happen would cause the vehicle to be un-maneuverable and damage the tires and/or axle. The reverse caster of the axle is accomplished by adding a pivoting mechanism to the axle that is activated when the power unit&#39;s transmission is shifted into reverse. 
     An alternative arrangement of the body unit and power unit is compatible with ocean shipping containers. According to current practice, shipping containers are off loaded from the ship and then positioned on and locked to a semi-trailer chassis, which is hauled from the port dock by a traditional tractor type vehicle. Typically, only one container (regardless of length) can be hauled at a time due to available equipment configurations. According to an alternative embodiment of the invention, a chassis unit, having no body, but including the extendible frame and axle and coupling structure described above, can accept a shorter (typically 20′) shipping container. This unit can be coupled to a power unit, and an additional current, traditional container semi-chassis loaded with any length shipping container can also be pulled by the same Power Unit, thus improving freight efficiency by 50% (two containers moved in a single trip). 
     The invention has been described in terms of preferred principles, embodiments, and structure; however, those skilled in the art will understand that substitutions of equivalent structure may be made for the structure described here without departing from the scope of the invention as defined by the appended claims.