Abstract:
A unit for returning a cover of a trailer comprising a first portion, a cord, and a spring. The spring is connected to the first portion. The cord having first and second ends, the first end of the cord being connectable to the first portion, the second end of the cord being connected to the cover, and the cord being wrappable around the first portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/261,899, filed Oct. 28, 2005, which is a continuation of U.S. patent application Ser. No. 10/664,806, filed Sep. 17, 2003, which is assigned to the assignee of the present application and which is hereby incorporated herein by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     Field of the Disclosure 
     This disclosure relates to covers for truck trailers, and more particularly to a trailer cover system. 
     Many truck trailers, particularly those hauling loose loads such as sand and gravel, need a cover to prevent the wind from blowing load particles off the load bed. Various apparatus have been devised for covering a trailer load. Some such apparatus include a motor for selectively winding a flexible cover. An effective cover should be one which is easily operated by the truck driver so as to selectively cover and uncover the load from the convenient location of the truck cab. My U.S. Pat. No. 5,031,955, the disclosure of which is hereby incorporated by reference, provides a truck cover which may be conveniently motor operated from the cab of a truck to extend the cover from a winding assembly proximate the front of the truck bed and toward the rear of the truck bed. 
     A need also exists for systems that cover the trailer from side to side. For instance, U.S. Pat. No. 5,328,228 shows a cover for truck bed and cargo. Similarly, U.S. Pat. No. 5,924,758 shows a roll assist mechanism for tarp systems. My U.S. Pat. Nos. 6,206,449 and 6,527,331, the disclosures of which are also hereby incorporated by reference, show a side-to-side truck cover system including a pair of arms, each of which includes a base and an extension. 
     One aspect of the present invention is a wall section for a trailer. The wall section comprises a male end and a female end. The male end includes a central recess having at least one protrusion on each side of the central recess, the protrusions defining respective lateral recesses. The female end includes a central protrusion having at least one lateral protrusion on each side of the central protrusion, the central protrusion and the lateral protrusions defining respective recesses. Accordingly, an object of this invention is to provide an apparatus of the type described above for use on a trailer. 
     Another object of this invention is to provide an apparatus of the type described above for use in connection with covering the trailer. 
     Still another object of this invention is to provide an apparatus of the type described above for use in a system that provides selective, powered control over covering and uncovering the trailer. 
     Still another object of this invention is to provide an apparatus of the type described above that utilizes a relatively reduced number of small components. 
     Still another object of this invention is to provide an apparatus of the type described above that minimizes damage done to the apparatus during loading operations. 
     These and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. 
         FIG. 1  is a front schematic view of a trailer including an apparatus according to the present invention for covering the trailer; 
         FIG. 2  is a rear schematic view of the trailer shown in  FIG. 1 ; 
         FIG. 3  is an enlarged view of a top rail shown in the portion of  FIG. 2  designated 
         FIG. 4  is a perspective view of the top rail; 
         FIG. 5  is a cross-sectional view of interlocking sections of one embodiment of a wall of the trailer; 
         FIG. 6  is a cross-sectional view of the wall sections joined together; and 
         FIG. 7  is a partial exploded isometric view of a cover return unit, and 
         FIG. 8  is an isometric view of the cover return unit showing the cord wrapped around one of the halves of the cover return unit and operatively connected to the cover return unit. 
       The use of the same reference symbols in different drawings indicates similar or identical items. 
     
    
    
     DETAILED DESCRIPTION 
     According to various aspects of the present disclosure, With reference to the drawings, the preferred embodiments of the present invention will be described.  FIGS. 1 and 2  show an arm assembly  10  for a flexible tarp or cover  12  of a truck trailer  13 . The arm assembly  10  comprises a base  14  and an extension  18 . The base  14  is preferably mounted to the trailer at a base plate  20  proximate the top of the front  22  of the trailer. While the base plate  20  is shown in the drawings centered and closer to the top of the trailer  13 , it should be appreciated that the base plate may be mounted at a variety of locations. 
     The base plate  20  includes at least one spiral torsion spring. Preferably, one end of each of the springs engages a groove formed in the surface of and extending a substantial portion of the length of a center shaft, while the other ends of the springs cooperate with a locator pin. Further details of this arrangement are taught by U.S. Pat. No. 5,887,937, which is hereby incorporated by reference. In this way, the base  14  is normally biased clockwise as shown in  FIG. 1  across at least a portion of the front  22  of the trailer from a mostly or fully uncovered, stowed position, through intermediate positions (only one of which is shown) and toward a deployed position. 
     The extension  18  is pivotally connected at one of its ends to the base  14  by a hinge or knuckle  28 . Preferably, a knuckle shaft is welded or otherwise fixed to one of a pair of plates extending from an upper end of the base  14 . The knuckle shaft extends through the lower end of the extension  18  such that the knuckle shaft is rotatable with respect to the extension. One end of each of a plurality of spiral torsion springs preferably engages an axial groove formed in the knuckle shaft. The other ends of the springs cooperate with a knuckle locator pin. Further details of this arrangement are taught by U.S. Pat. No. 5,944,374, which is hereby incorporated by reference. 
     In this way, the extension  18  is also normally biased clockwise as shown in  FIG. 1 . Rotation of the extension  18  in both directions may be limited by one or more stops which are preferably in the form of plates  29 . The plates  29  are welded or otherwise attached to the knuckle  28 , and extend inwardly therefrom to engage the extension and prevent overrotation. Another stop may be welded or otherwise attached to the front  22  of the trailer to limit the pivotal movement of the base  14 , as taught by U.S. patent application Ser. No. 09/957,202 filed Sep. 20, 2001, the disclosure of which is hereby incorporated by reference. 
     A motor  30  is mounted on the distal end of the extension  18 . A rotatable reel  32  extends from the motor  30 , and is operatively connected to one end of the cover  12  so as to function as a take-up spool. The other end of the cover  12  is clamped, riveted, or otherwise fixed at one or more points along a line below the top of one side  34  of the trailer, such as at one or more openings  36  along a top rail  38 . As shown in  FIGS. 3 and 4 , the top rail  38  includes one or more metal or plastic pieces, such as extruded or pultruded aluminum or composite fiberglass polymer. The top rail  38 , and an opposite top rail  60 , include generally depending legs  39  and  40  that are adapted to be mounted over the top of the trailer wall  34  or the opposite trailer wall  41 . The legs  39  and  40  may be fixed to the trailer walls in any conventional manner, such as by welding, riveting or bolting. The trailer may also be provided with front and rear end caps, which are not shown, in order to provide a uniform wall height around the perimeter of the trailer, if the front and rear walls of the trailer are not already high enough. 
     The top rails  38  and  60  also each include a major interior surface  42 , a major exterior surface  44 , and one or more ribs  46 ,  48 ,  50 ,  52  and  54  extending from one or both of the surfaces  42  and  44 . In a preferred embodiment shown in the figures, the ribs  46 ,  48 ,  50  and  52  all meet at a reinforced section  55  proximate the exterior surface  44 . A locking channel portion  56  of the exterior surface  44  is concave, in order to accommodate the stowed tarp spool  32  as shown in  FIGS. 1 and 2 . The concave portion  56  of the top rail  38  includes the opening  36 , into which the stationary end of the tarp  12  may be anchored in any well known fashion. In a preferred embodiment, the tarp  12  is attached to the top rail  38  by sliding a tube  57  through a pocket in the stationary end of the tarp, and then sliding the stationary end of the tarp and the tube through a void  58  in the top rail with the tarp extending through the opening  36 . The top rail  60 , of course, does not require an opening similar to the opening  36 . 
     For either of the top rails  38  or  60 , the exterior surface  44  preferably includes a rounded lip  62  that extends to a point at or below the uppermost extent of the concave surface  56 . In the fully uncovered position, the cover  12  is wound on the reel  32  until the reel resides generally proximate the concave surface  56 . In this position, the trailer may dump rearwardly or in either the clockwise or counterclockwise direction without interference from the retracted cover. 
     The motor  30  is preferably provided with a brake which allows, among other things, for the apparatus  10  to remain in the stowed position. The lip  62  facilitates retention of the reel  32  in the stowed position. When the brake is released, the base  14  swings toward the driver&#39;s side  41  of the trailer, and the springs of the knuckle  28  also bias the extension  18  clockwise as shown in  FIG. 1  toward the side  41  of the trailer so as to hold the cover  12  in tension. The motor  30  may be powered, from within or without the cab of the truck, to facilitate this operation. Further details of one embodiment of the motor are taught by U.S. Pat. No. 5,829,819, which is hereby incorporated by reference. In this way, the cover  12  is pulled off of the reel  32  and extended over the trailer. The motor  30  can be reversed to drive the reel  32  and retract the cover  12  against the tension force of the springs to uncover the load bed. 
     The top rail  60  is provided with a profile generally similar to the profile of the top rail  38  so that the motor  30  drives the reel  32  within the concave portion of the top rail  60 , where the lip of the top rail  60  and the motor braking function may be used to hold the cover  12  in the deployed position. The top rails  38  and  60  thus allow the tarp reel  32  to reside close to the sides of the trailer in both the opened and closed positions. Because the tarp reel does not rest on the top of the trailer when the tarp is opened or closed, the overall height of the trailer and the possibility of a loader causing harm to the tarp assembly are reduced. 
     Any rotation of the base  14  less than about 250 degrees is contemplated, and in a preferred embodiment the base sweeps out an arc of about 120 degrees. Any rotation of the extension  18  relative to the base  14  is also contemplated, and in a preferred embodiment the extension rotates a total of about 250 degrees. By varying the position of the locator pins, the preload of the springs, the number of springs and/or the spring constant of the springs, the forces biasing the base and the extension toward the deployed position are variable. In a preferred embodiment, eight springs are used to bias the base  14 , and three springs are used in the knuckle  28  between the base and the extension  18 . In this arrangement the knuckle  28  opens relatively quickly, thus accommodating the weight of the axle, cover, and motor  30 , and allowing the motor to swing from either its fully covered or uncovered place and clear the top rail  38  or  60 . 
       FIGS. 5 and 6  show interlocking sections  70  and  72  that may be used to form the walls  34  and  41  of the trailer. The sections  70  and  72  are generally identical, and of course two or more may be needed to form the extent of a trailer wall, depending upon the length of the sections and the length of the wall required. The sections  70  and  72  have substantially smooth inner and outer sides joined by cross ribs  74 . Each wall section includes a male end  76  and a female end  78 . The male end  76  of one wall section is adapted to interlock with the female end  78  of an adjacent wall section. In a preferred embodiment, the male ends  76  include a central recess  80  flanked by protrusions  82  and  84 . The protrusions  82  and  84  in turn define respective lateral recesses  86  and  88  generally proximate the outer surfaces of the wall sections. The female ends  78  include a central protrusion  90  flanked by lateral protrusions  92  and  94  generally proximate the outer surfaces of the wall sections. The central protrusion  90  and the lateral protrusions  92  and  94  in turn define respective recesses  96  and  98 . 
     When brought together, the lateral protrusions  92  and  94  lockingly engage the lateral recesses  86  and  88 , respectively. At the same time, the protrusions  82  and  84  lockingly engage the recesses  96  and  98 , while the central protrusion  90  fits within the central recess  80 . The sections  70  and  72  are preferably extruded from aluminum. After the wall sections are preassembled, with or without the top rails, the entire preassembly may be joined, such as by welding, to the metal rails of the truck bed. Because the individual wall sections do not need to be welded together, substantial time and effort may be avoided. 
     Referring again to  FIG. 2 , an elastic cord may be provided proximate the rear of the trailer for biasing the reel  32  toward the driver&#39;s side  41  of the trailer. More preferably, a cover return unit  100  is provided. The cover return unit  100  is preferably mounted on the driver&#39;s side  41  of the trailer, at or near the rear of the trailer. As shown in  FIG. 7 , the cover return unit  100  preferably includes two halves  102  and  104  molded in an automotive grade plastic and rotatably mounted on an external pivot pin assembly  106 , and a large spiral torsion  108  contained inside the halves  102  and  104 . The pivot pin assembly  106  is secured to the trailer, preferably by bolts extending through holes  110 . One end  112  of the spring  108  is secured in a groove  114  in the pivot pin assembly  106 , and another end  116  of the spring  108  is secured, such as by insertion in a groove  118 , to the cover return half  102 . 
     A sufficient length of nylon rope or cord  119 , shown in  FIGS. 2 and 3 , is wrapped around the assembled cover return unit  100 , with one end attached to the unit itself such as by a cable clamp secured by one of the screws extending through holes  120 . See  FIG. 8 . The other end of the rope  119  extends through a hole in an end cap secured on the back end of the tarp axle  32  such as by screws  122 . The rope  119  is preferably knotted at this end to prevent it from being withdrawn through the hole in the end cap of the reel. As the tarp reel  32  rolls toward the passenger side  34  of the trailer, i.e. uncovering the trailer, the rope  119  unspools from the cover return unit  100 . As the rope unspools, it rotates the unit  100  to wind the spring  108  and store rotational torque. When the cover  12  is returned to the driver&#39;s side  41  of the trailer, the cover return unit  100  pulls on the back of the axle  32  using the torque stored in the spring  108 . In operation the spring  108  is rotatably mounted on the pivot pin assembly  106  about a spring axis  77  which is perpendicular to the reel axis  79  about which the tarp reel  32  rotates (as shown in  FIG. 2 , for example). Movement of the rope  119  unwraps the cover  12  from the closed position of  FIG. 2  wrapped around the reel to any partial or fully opened position (such as shown in  FIG. 1 ) since the rope  119  is operatively connected to the cover  12 . During this process, the rope  119  unwinds around the halves  102 ,  104 . Since the rope  119  is operatively connected to the first half  102 , the halves rotate with respect to the pivot pin assembly  106 . This rotation urges the spring  108  to rotate about the spring axis  77 , producing a rotational torque that pulls on the rope  119 , in a direction urging the cover  12  toward the closed position. Thus, the cover return unit  100  assists with returning the cover  12  to the closed position. 
     It should be understood that while the forms of the invention shown and described above constitute preferred embodiments of the invention, they are not intended to illustrate all possible forms thereof. The words used are words of description rather than limitation, and various changes may be made without departing from the spirit and scope of the invention disclosed.