Abstract:
A tailgate system for a dump body of a vehicle capable of operation in a plurality of modes includes a tailgate pivotally connected to side walls along an upper tailgate end for operation in a first mode and pivotally connected to one of the side walls along a tailgate side for operation in a second mode. To convert the tailgate from the first to the second mode of operation, a ball and socket are engaged forming a pivot point around which the tailgate can rotate in the second mode.

Description:
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/364,686, filed Mar. 15, 2002. 

   TECHNICAL FIELD 
   The present invention relates generally to vehicle bodies, and more specifically, to a tailgate system for dump trucks and dump trailers or the like, capable of operation in a plurality of modes. 
   BACKGROUND OF THE INVENTION 
   Tailgates are generally known in combination with dump truck or dump trailer bodies (hereinafter referred to collectively as dump bodies). Conventional dump body tailgates are supported for pivotal movement during operation around upper pivot pins. More specifically, the tailgates rotate around upper pivot pins generally aligned with an upper end or top rail of the tailgate allowing a lower end of the tailgate to freely swing open as hauled materials are dumped from the dump body. This first mode of operation is referred to as a conventional dumping mode. In addition, it is  known to disengage at least one of the pivot pins along the upper end of the tailgate to allow for rotation of the tailgate around one side thereof. This second mode of operation is referred to as a swing gate mode in which the tailgate of the dump body opens much like a typical barn door. 
   One such prior art dump body capable of operation in a conventional and a swing gate mode of operation is Manufactured by Bibeau Enterprises, Inc. In the conventional mode of operation, a tailgate pivots around upper pivot pins. To transition the Bibeau dump body to the swing gate mode of operation, an operator must manually disengage the upper pivot pins through operation of a ground control assembly shown in  FIG. 1 , and manually engage a ball and socket assembly shown in  FIG. 2  to provide a pivot point around which the tailgate will rotate. 
   The ground control assembly, generally designated reference numeral  10 , includes a lever  11  attached to an upwardly extending arm  12  which are externally positioned adjacent a rear corner post  13  of a dump body  14 . The upwardly extending arm  12  in turn is attached to and controls a latching member  15 . Operation of the lever  11  raises the upwardly extending arm  12  which in turn raises the latching member  15  causing the member to pivot and release one of the upper pivot pins  16 . Although this ground control assembly  10  is adequate to perform its intended function of disengaging the upper pivot pin  16 , the assembly stands off from the dump body sidewall making it prone to damage thru contact with other heavy equipment, hauled materials, and even tree limbs for example. In addition, the assembly is rather unsightly in contrast to the  generally sleek lines of a dump body. Accordingly, a need is identified to protect such a ground control assembly from such contact type damage while maintaining the overall aesthetic appeal of the dump body. 
   As shown in  FIG. 2 , the ball and socket assembly  18  of the Bibeau dump body includes a ball  19  supported by a mounting head  20  and a socket  21 . The socket  21 , shown in phantom for clarity, is designed for manual rotation through an angle of approximately forty-five degrees for engaging and disengaging the ball. The mounting head  20  is welded to a lower end of the tailgate  22  adjacent a rear corner post  23  of the dump body  14 . A mounting shank  24  supporting the ball extends through the mounting head  20  and a nut  25  secures the ball  19  to the mounting head for movement with the lower portion of the tailgate  22  when the socket is disengaged. 
   A pair of stub arms  26  welded to the rear corner post  23  of the dump body support the socket  21  for pivotal movement. The socket  21  is secured in engagement with the ball  19  by a collar  27  rotatably supported generally by the mounting head  20 , and a locking pin  28  attached to the socket. In the swing gate mode, the collar  27  that is also shown in phantom for clarity is rotated into position directly beneath the ball  19 . As the socket  21  is lowered into engagement with the ball  19 , a shaft of the locking pin  28  extends through an aperture defined by the collar  27  and is secured in place with a cotter pin or the like. Once secured, upward rotation of the socket assembly is prevented by the collar contacting the ball.  
   Again, although this ball and socket assembly form a suitable pivot point around which the tailgate can pivot in the swing gate mode, the assembly includes numerous pieces making it cumbersome for a vehicle operator to manipulate, and making manufacturing difficult. Perhaps more importantly, the assembly is only manually operable from a position adjacent the rear of the dump body. Accordingly, a further need is identified for an assembly which is simpler to operate and manufacture, and preferably which is operable from alongside the vehicle or from a cab of the vehicle. 
   SUMMARY OF THE INVENTION 
   In accordance with a first aspect of the present invention, a body for a vehicle including a tailgate system capable of operation in a plurality of modes is disclosed. The body comprises a floor having a front wall and side walls attached thereto, and a tailgate having sides and upper and lower ends. The tailgate may be pivotally connected to the side walls along the upper tailgate end for operation in a first or conventional mode, and pivotally connected to one of the side walls along one of the tailgate sides for operation in a second or swing gate mode. 
   A socket may be attached to the tailgate for receiving and engaging a ball in the second mode of operation to form one of the pivotal connections along the tailgate side, and an actuator for moving the ball between a first disengaged position in the first mode of operation and a second engaged position in the second mode of operation may be  provided. In one embodiment, the actuator may be a lever which may be locked in the second engaged position in the second mode of operation by a locking mechanism. The lever may extend through a corner post attached to the sidewalls adjacent the tailgate sides for actuating movement of at least one of the ball and socket. Alternatively, the actuator may be fluid operated. More specifically, a valve may be operatively connected between the actuator and a fluid reservoir for selectively moving the actuator between the first and second positions. A controller may be provided for selectively opening and closing the valve and may be positioned in a cab of the vehicle supporting the tailgate system or otherwise for convenient operation. 
   In accordance with a second aspect of the present invention, a latching member for engaging one of the pivot pins along the upper tailgate end in the first mode of operation and disengaging the pivot pin in the second mode of operation may be provided. The latching member is moved between engaged and disengaged positions by a latching member actuator. The latching member actuator may be fluid operated wherein a fluid reservoir and a valve operatively connected between the actuator and the reservoir are provided. Alternatively, the latching member actuator may include a handle connected to an arm extending between the handle and the latching member. In accordance with another aspect of the present invention, at least part of the actuator may be enclosed within a corner post of the vehicle to prevent contact type damage thereto while still maintaining the sleek lines and overall aesthetic appeal of the dump body.  
   As indicated above, the body supporting the tailgate system may be a dump truck including a cab or a dump trailer including a tractor for pulling the trailer and tailgate system. In accordance with another aspect of the present invention, a controller for selectively opening and closing the valve connected between the actuator and the reservoir may be positioned within the cab or tractor. 
   In an alternate embodiment of the present invention, a body comprises a floor having a front wall and side walls attached thereto, and a tailgate having sides and upper and lower ends. The tailgate may be pivotally connected to the side walls along the upper tailgate end for operation in a first or conventional mode, and pivotally connected to one of the side walls along one of the tailgate sides for operation in a second or swing gate mode. A socket or ball may be attached to the tailgate for receiving and engaging a ball or socket, respectively, in the second mode of operation to form one of the pivotal connections along the tailgate side, and an actuator for moving the ball or socket between a first disengaged position in the first mode of operation and a second engaged position in the second mode of operation may be provided. 
   In accordance with still another aspect of the present invention, a control means may be substantially positioned within a corner post attached to the sidewall adjacent the tailgate for selectively disengaging one of upper pivot pins in support of operation in the second mode. The control means may include a latching member for engaging one of the pivot pins along the upper tailgate end in the first mode of operation and  disengaging the pivot pin in the second mode of operation. The latching member is moved between engaged and disengaged positions by a latching member actuator. The latching member actuator may be fluid operated wherein a fluid reservoir and a valve operatively connected between the actuator and the reservoir are provided. Alternatively, the latching member actuator may include a handle connected to an arm extending between the handle and the latching member. As indicated above, at least part of the actuator, handle, and arm may be enclosed within the vehicle corner post to prevent contact type damage thereto while still maintaining the sleek lines and overall aesthetic appeal of the dump body. 
   In accordance with a method of the present invention, a dump body tailgate may be converted from a first or conventional mode of operation wherein the tailgate is pivotally connected to side walls along an upper tailgate end to a second or swing gate mode of operation wherein the tailgate is pivotally connected to one of the side walls along one of the tailgate sides. The method may include the steps of moving a ball from a first disengaged position for operation in the first mode of operation to a second position in engagement with a socket attached to the tailgate, and disengaging a pivot pin along the upper tailgate end. 
   The method of converting the dump body tailgate, may further include actuating a lever attached to the ball and locking the lever in position once the ball and socket are engaged. The actuating step may further include opening a valve operatively connected between an actuator and a fluid reservoir to move the ball into engagement with the socket. In  accordance with still another aspect of the method, the step of opening the valve may be performed from a cab of a vehicle supporting the dump body tailgate. 
   The disengaging step of the present invention may include transitioning a latching member from a first position in engagement with the pivot pin to a second disengaged position by contacting the latching member with an arm. As indicated above, the arm may be enclosed within a corner post of the dumb body for engaging and disengaging the latching member. In addition, the step of moving may include actuating a lever attached to the ball. 
   The following description shows and describes a preferred embodiment of this invention simply by way of illustration of one of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments, and its several details are capable of modifications in various, obvious aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings: 
       FIG. 1  is a partial side elevational view of a ground control  mechanism for releasing a pivot pin of a prior art dump body; 
       FIG. 2  is a perspective view of a ball and socket assembly for creating a pivot point of a prior art dump body; 
       FIG. 3  is a perspective view of dump body including a tailgate system for operation in a plurality of modes; 
       FIG. 4  is a perspective view of a body including a tailgate and ground control assembly used to disengage an upper pivot pin to allow operation of the tailgate in the second mode; 
       FIG. 5  is a cross-sectional view of an alternate ground control assembly positioned inside a rear corner post of the dump body; 
       FIG. 6  is a perspective view of a ball and socket assembly of the body; 
       FIG. 7  is a perspective view of a rear portion of a dump body showing a manual lever to move or pivot a lifting arm about a bushing in order to raise a ball into engagement with a socket for swing mode operation; and 
       FIG. 8  is a cross-sectional side view showing movement of an alternate ball assembly between a disengaged position for operation in a conventional mode, and an engaged position for operation in a swing mode. 
   

   Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.  
   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to the perspective view of  FIG. 3 , there is shown a dump body  30  for a vehicle, i.e, dump truck or dump trailer, including a tailgate that is capable of operation in a plurality of modes. The body  30  includes a front wall  31  and side walls  32  attached to a floor  33 , and a tailgate  34 . In a first or conventional mode of operation, the tailgate  34  rotates around upper pivot pins  35  generally aligned with an upper end of the tailgate, and in a second or swing gate mode of operation, the tailgate rotates around a side of the tailgate. 
   As best shown in  FIG. 4 , one of the upper pivot pins  35   a  in the present embodiment is temporarily engaged by a blocking bar  36  and the remaining upper pivot pin  35   b  is permanently engaged. In this manner, the tailgate  34  is allowed to pivot generally around its upper end during unloading in the conventional mode of operation. Lower pivot pins  37  are similarly provided that secure the lower end of the tailgate  34  together with the upper pivot pins  35  in a closed position during loading and travel of the dump body  30 . 
   In order to accommodate conversion between modes of operation, the dump body  30  of the present invention further includes a ground control assembly  38  and a ball and socket assembly  39 . In accordance with the broad teaching of the present invention, the ground control assembly  38  may be positioned adjacent a rear corner post  40  of the dump body  30  as shown in  FIG. 4  or substantially within the rear corner post as shown in  FIG. 5 . Since the ground control assembly  38  is  substantially the same whether positioned adjacent to or within the rear corner post  40  of the dump body  30 , only the ground control assembly positioned within the rear corner post will be described in detail at this time. 
   As best shown in  FIG. 5 , the ground control assembly  38  generally includes a hand lever  41  linked to an upwardly extending arm  42 . The upwardly extending arm  42  is attached at an upper end  43  to a latching member  44  for securing one of the upper pivot pins  35   a  in position during operation in the conventional mode, or during loading and travel of the dump body. Operation of the lever  41  (shown by action arrow A) raises the upwardly extending arm  42  which in turn raises a lower portion of the latching member  45  causing the member to pivot about pivot point P 1 . The upward movement of the lower portion of the latching member  45  and pivotal movement lower a blocking bar  46  of the latching member thus releasing one of the upper pivot pins  35   a  and freeing one side of the tailgate  34  to swing open. 
   Referring back to  FIGS. 3 and 4 , lower pivot pins  37  extend from each side of the lower end of the tailgate  34  which are similarly engaged by lower latching members  47  during loading and travel of the dump body  30 . During operation in either the conventional or swing gate mode, the lower pivot pins  37  are disengaged through operation of an air tailgate switch (not shown) as is well known in the art. The air tailgate or V8S switch is typically positioned in a cab of the vehicle. When activated, air pressure from an air tank positioned on a chassis of the dump body  30  is  applied to a pneumatic cylinder causing the cylinder to stoke outwardly. The outward stroke and movement of the linkage operate to move or pivot the latching members  47  which disengage the latching members from the pivot pins  37 . The arrangement of the latching members  47  and pivot pins  37  is best illustrated in  FIG. 5 . Although a similar pneumatic cylinder and linkage assembly are shown in  FIG. 6 , the air tailgate switch, pneumatic cylinder and linkage assembly arrangement which actuate the latching members  47  are well known in the art and are not shown herein. 
   As shown in  FIG. 1  and perhaps best shown in the perspective view of  FIG. 6 , a ball and socket assembly  39  of the dump body  30  includes a ball assembly  50  and a socket assembly  51 . The ball assembly  50  includes a pivot bracket  52  welded to a rear corner post  53  of the dump body  30  (see  FIG. 1 ). A bushing  54  is welded to the bracket  52  and provides a pivot point for lift arm  55 . A mounting plate  56  is formed on or otherwise attached to the lift arm  55  and supports a ball  57  for movement between a disengaged position in the conventional mode of operation and an engaged position in the swing gate mode of operation. A mounting shank  58  supporting the ball  57  extends through the mounting plate  56  and a nut (not shown) secures the ball thereto. 
   The mounting plate  56 , the mounting shank  58 , ball  57  and nut are supported by the dump body  30  and do not move with the lower portion of the tailgate  34  but independently about bushing  54 . As best shown in  FIG. 1 , the socket assembly  51  is mounted to and moves with the tailgate  34 . Referring back to  FIG. 6 , the socket assembly  51  includes a hitch  plate  60  which supports a socket  61 . A gusset  62  in the present embodiment provides additional strength to the socket assembly  51 . It should be understood that the ball assembly and socket assembly may be mounted to the tailgate  34  and dump body  30  and actuated in any known manner in accordance with the broad teaching of the present invention. 
   In the present embodiment, for example, the ball assembly  50  is attached to a pneumatic cylinder  63  mounted to the sidewall  32  of the dump body  30 . The pneumatic cylinder  63  is attached to the lift arm  55  of ball assembly  50  via an appropriate linkage (not shown) and clevis  64 . During unloading in the swing gate mode of operation, the lift arm  55  and ball  57  are raised into engagement with socket  61  through operation of the pneumatic cylinder  63 . A second air switch, or V8S switch, is positioned in the cab of the dump truck or dump trailer in the present embodiment for activating the cylinder  63 . When activated, air pressure from an air tank (not shown) positioned on the chassis of the dump body  30 , for example, is applied to the pneumatic cylinder  63  causing the cylinder to stroke outwardly. The outward stroke and movement of the linkage and clevis  64  operate to move or pivot the lifting arm  55  about bushing  54  which raises the ball  57  into engagement with the socket assembly  51  and more specifically, the socket  61 . The ball  57  is secured in the socket  61  until the air switch is deactivated by the operator in the cab. 
   In an alternate embodiment of the present invention shown in  FIG. 7 , a lever  66  may be used to manually move or pivot the lifting arm  55  about bushing  54 . Movement of the lever  66  similarly raises the ball  57   into engagement with the socket  61 . In the present embodiment, the lever  66  is mounted just forward of the rear corner post  40  along a lower portion of the sidewall  32  of the dump body  30 . Of course, other positions for the lever may be used in accordance with the present invention. In addition, a locking mechanism  67  is utilized in the present embodiment to prevent accidental operation of the lever  66 . 
   In another alternate embodiment of the present invention shown in  FIG. 8 , perhaps a simpler ball assembly  68  is described. The ball assembly  68  includes a mounting plate  69  welded to a rear corner post  70  of a dump body. The mounting plate  69  includes a pair of ears  71  which support a bushing  72 . The bushing  72  provides a pivot point for lift arm  73 . A mounting plate  74  is formed on or otherwise attached to the lift arm  73  and supports a ball  75  for movement between a disengaged position (shown in phantom lines) in the conventional mode of operation and an engaged position (shown in solid lines) in the swing gate mode of operation. A mounting shank  76  supporting the ball  75  extends through the mounting plate  74  and a nut  77  secures the ball thereto. As in the earlier described embodiment, the mounting plate  74 , the mounting shank  76 , ball  75  and nut  77  are all supported by the dump body sidewall and do not move with the lower portion of the tailgate  78  but independently about bushing  72 . The socket assembly  79 , on the other hand, includes a hitch plate  80  which supports a socket  81  and is mounted to and moves with the tailgate  78 . This alternate ball assembly  68  may also be manually operated utilizing a lever or operated utilizing a pneumatic cylinder or the like as are  described in detail above. 
   To transition from the conventional mode of operation to the swing mode of operation, the ball and socket must be engaged. In one embodiment of the present invention, the operator activates a pneumatic cylinder from the cab of the dump body forcing the ball upwards into engagement with the socket. Once engaged, the tailgate may be opened in the swing mode by releasing the lower pivot points of the tailgate through activation of another pneumatic cylinder from the cab of the dump body or manually, and finally by disengaging an upper pivot pin utilizing the ground control assembly. 
   The foregoing description of the present embodiments of the invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. For example, the ball assembly  50  may be mounted to and move with the tailgate  34 . In such an alternate embodiment, the socket assembly  51  is supported by lift arm  55  for pivotal movement about bushing  54  between a disengaged position in the conventional mode of operation and an engaged position in the swing gate mode of operation. 
   The present embodiments were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are  suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.