Abstract:
Apparatus for covering a payload of a semitrailer with a tarpaulin cover having an overhead structure including a first travel beam and a second travel beam. A carriage is movable on the first travel beam and second travel beam from a position where the carriage rests over the payload to be covered to a position spaced apart in a side-by-side relation with the payload to be covered. A rotatable drum upon which a cable is wound is mounted to the carriage and the connector is used for connecting a free end of the cable to the tarpaulin. An electric system or hydraulic system is used for selectively locating the rotatable drum in opposite directions.

Description:
This application claims the benefit of provisional application Ser. No. 61/063,961 filed Feb. 7, 2008. 
    
    
     BACKGROUND OF INVENTION 
     The present invention relates to apparatus for covering a semitrailer payload with a tarpaulin. When materials or commodities are hauled on flatbed trailers or semitrailers, many such materials or commodities must be covered with a tarpaulin to protect the goods from inclement weather. Various types of coverings are used to cover these payloads, the most common of which is tarpaulin. However, covering payloads on a flatbed trailer present several problems. If the tarpaulin is to be manually placed on top of the payload and the tarpaulin secured to the semitrailer, the workers must climb to the top of the payload with the tarpaulin and then position the tarpaulin over the payload and then tie down the tarpaulin to the semitrailer. These may require several workers working together. Therefore the process is time consuming and inefficient. Further, workers working on top of a payload are working at a height which may present dangers of the worker falling off the payload. 
     There are several known apparatus used for covering semitrailer payloads. For example, U.S. Pat. No. 6,502,709 shows an apparatus for pulling a tarpaulin up and over a payload; U.S. Pat. No. 6,811,202 to Hornady shows another apparatus for pulling a tarpaulin up and over a payload; and U.S. Pat. No. 6,857,620 shows apparatus for lifting a tarpaulin over a payload using fastening roller members for securing the tarpaulin cover to an arm which is lifted over the payload to be covered. 
     There is a need for an apparatus which is easy to use, can be operated by a single individual from ground level. A need also exists for apparatus which can be used to lift a tarpaulin completely to an overhead position and to drop the tarpaulin down on top of the payload whereby the tarpaulin can be secured to the semitrailer easily and efficiently. A need also exists for apparatus which can be used to cover payloads requiring multiple tarpaulins not requiring the flatbed or semitrailer to be driven in and then out of the apparatus for placement of the tarpaulins one at a time. 
     SUMMARY OF INVENTION 
     The apparatus according to the present invention includes an overhead track structure including a first pair of upright posts spaced apart from one another in a lateral direction with respect to the position of the semitrailer payload being covered and a second pair of upright posts spaced apart from one another in a lateral direction with respect to the position of the semitrailer payload being covered. The second pair of upright posts arranged in spaced apart and parallel relation with the first pair of upright posts in a longitudinal direction with respect to the position of the semitrailer being covered. A first travel beam extends across and is secured to the top of each of the first pair of upright posts and a second travel beam extends across and is secured to the top of each of the second pair of upright posts. The first travel beam and second travel beam each have an outrigger portion extending outwardly from their respective upright posts in the same direction. A carriage is provided which has end beams provided with trolleys for riding on the first and second travel beams. The carriage which is carried by the trollies is movable from a position where the carriage rests on the first and second travel beams between the first pair of upright posts and the second pair of upright posts to a position where the carriage rests on the outrigger portions of the first and second travel beams. A series of rotatable cable drums are mounted to the carriage upon which a cable is wound. A connector is used for connecting a free end of the cable to the tarpaulin. A bi-directional motor is connected to a power source and a controller is electrically connected to the bi-directional motor for running the motor in either direction. Drive shafts connect the motor with each of the cable drums for rotating the cable drums to either drop the cables downwardly for attaching to the tarpaulin and then rotating the drums in the opposite direction whereby the cables lift the tarpaulin to an overhead position. Once the tarpaulin is picked up, and a truck driven adjacent to the tarpaulin, the tarpaulin is moved by the carriage over the top of the payload and the motor used to rotate the cable drums to drop the tarpaulin on top of the payload. The payload may then be secured to the semitrailers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be clearly understood and readily carried into effect, a preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings wherein: 
         FIG. 1  is a perspective elevational view of an apparatus according to the present invention; 
         FIG. 2  is left side perspective view of the apparatus shown in  FIG. 1 ; 
         FIG. 3  is a schematic bottom view of a carriage used with the present invention; 
         FIG. 4  is a detail bottom perspective view of the carriage shown in  FIG. 3 ; 
         FIG. 5  is a second detail bottom perspective view of the carriage shown in  FIG. 3 ; 
         FIG. 6  is a detail perspective view of a tarp connector used with the present invention for mounting to a tarpaulin; 
         FIG. 6A  is a detail perspective view of a tarp connector used with the present invention mounted to a tarpaulin; 
         FIG. 7  is an exploded elevational view of the tarp connector shown in  FIG. 6 . 
         FIG. 8  is a right side end view of the tarp connector shown in  FIG. 7 ; 
         FIG. 9  is a cross-sectional view taken along the line  9 - 9  in  FIG. 8 ; 
         FIG. 10  is an elevational view of the tarp connector shown in  FIG. 6  with a cable lifting positioned for lifting a tarpaulin; 
         FIG. 11  is an elevational view of the tarp connector shown in  FIG. 10  with a lifting cable positioned for connecting the tarp connector to a tarpaulin; 
         FIG. 12  is a detail perspective view of a lifting cable used with the present invention; 
         FIG. 13  is a perspective view of the lifting cables attached to a tarpaulin; 
         FIG. 14  is a perspective view of a semitrailer load positioned for draping the tarpaulin over the payload; 
         FIG. 15  is a view of an electrical switch used with the present invention; 
         FIG. 16  is a perspective view of a semitrailer payload covered by a tarpaulin; 
         FIG. 17  is a schematic bottom view of a carriage used with the second embodiment of the present invention; 
         FIG. 18  is a partial perspective end view of apparatus according to a second embodiment of the present invention; and 
         FIG. 19  is a perspective elevational view apparatus according to a second embodiment of the present invention with a semitrailer payload positioned for draping the tarpaulin over the payload. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     A tarp lifter  10  according to the present invention is shown in  FIGS. 1 and 2 . The tarp lifter  10  includes four upright posts  12 ,  14 ,  16  and  18 . 
     A travel “I” beam  20  has one end mounted to an upper end of post  4 . The travel beam  20  is also mounted to an upper end of the post  16  leaving an outrigger portion  23 . Similarly a travel “I” beam  22  has one end mounted to an upper end of post  12 . The travel beam  22  is also mounted to an upper end of post  18  leaving an outrigger portion  25 . 
     A carriage  24  is carried by travel beams  20  and  22  as shown in  FIG. 1 . The carriage  24 , shown in detail in  FIG. 3 , includes a frame having spaced apart and parallel side beams  26  and  28  and a plurality of brace beams  30  secured to beams  26  and  28 . A pair of end beams  32  are mounted at the opposite ends of frame side beams  26  and  28  as shown in  FIG. 3 . A pair of trolleys  34  are mounted to each of the end beams  32  as shown in  FIG. 3 . The trolleys are mounted to ride on the respective flanges of the travel beams  20  and  22  as shown in  FIGS. 1 and 2 . The carriage  24  is thus enabled to ride back and forth on the travel beams  20  and  22 . 
     Four support beams  36  extend laterally across the frame side beams  26  and  28  as shown in  FIG. 3 . At each end of the support beams  36  is mounted an extended frame member  38  as shown in  FIG. 3  and  FIG. 4 . A depending supporting member  40  is mounted to each extended frame member  38  as shown in  FIGS. 1 and 4 . At the distal end of the depending support member  40  is provided a guide ring  42  which acts as a cable guide as explained below. 
     A motor mount member  44  has opposite ends secured to frame side beams  26  and  28  as shown in  FIG. 3 . A double output motor with worm drive gear  46  is mounted on the member  44 . A first drive shaft  48  is connected to the motor  46  and has an opposite end connected to a four shaft outbox gearbox  50 . A second drive shaft  52  is connected to the gearbox  50  and has an opposite end connected to a four shaft output gearbox  54 . A third driveshaft  56  has one end connected to the motor  46  and an opposite end connected to a four shaft output gearbox  58 . A fourth drive shaft  60  has one end connected to the gearbox  58  and an opposite end connected to a four shaft gear box  62 . 
     Each of the gearboxes  50 ,  54 ,  58  and  62  have laterally extending drive shafts  64  connected to a respective gearbox as shown in  FIG. 3 . The free end of each of the drive shafts  64  is connected to a wind up cable drum  66 . 
     A cable  68  has one end connected to the cable drum  66  and when the motor  46  is activated, the cable  68  can either be wound up on cable drum  66  or unwound from cable drum  66 . The opposite end of cable  68  is first threaded through guide ring  42  and then connected to a tarp connector  70  as shown in  FIGS. 6 through 11 . Although a specific tarp connector  70  is shown and described and is used in a preferred embodiment, other well known tarp connectors such as hooks or rings could be used equally as well. 
     The tarp connector  70  is a two piece unit having a first cylindrical part  72  and a second cylindrical part  74 . The part  72  has a threaded extension  76  which is threadably received by part  74  to form a unit  70  as shown in  FIG. 10 . The part  74  has a “L” shaped slot  78  which extends into a cylindrical bore  80  as shown in  FIG. 9 . The bore  80  extends to but not through the end wall  81  of part  72  as shown in  FIG. 8 . 
     The cable  68  has a single shank ball  82  mounted to a free end of cable  68  as shown in  FIG. 12 . The single shank ball  82  is sized to be slidably received by bore  80  but sized larger than the slot  78  so that when the single shank ball  82  is mounted in part  74 , the cable  68  is slidably secured to the tarp connector  70 . 
     In using the tarp connector  70 , the cable  68  is positioned to extend out through the end wall  81  of part  74  as shown in  FIG. 11 . The tarp connector  70  is then threaded through tie down “D” rings  84  conventionally provided on a tarpaulin  86  as shown in  FIGS. 6 and 13 . After the tarp connector  70  is threaded through the “D” rings  84 , the cable  68  is moved to the position as shown in  FIG. 10  and in  FIG. 6A . In this position the tarp connector  70  is prevented from being drawn back through “D” rings  84  when the motor  46  is activated to wind the cable  68  onto the cable drums  66 . The cables  68 , under motor control, lift the tarp upwardly to a position as shown in  FIG. 2 . 
     The motor  46  is an electrical motor and is connected to a power source with an electrical cable  92  which has been releasably wound on a spring loaded cord reel  94 . The electrical cable  92  is connected to an electrical junction box  96 . Control switch  98  is electrically connected with a control cable  100  to the electrical junction box  96 . The control switch  98  is shown in  FIG. 15 . The control switch  98  includes four push button switches which activate the selected motorized device as long as the switch is depressed. Push button switch  104  controls the motor  46  to raise the cables  68 . Push button switch  106  controls the motor  46  to lower the cables  68 . The push button switch  108  may be used to actuate a conventional tractor drive trolley  146 , as shown in  FIGS. 17-19 , to move the carriage  24  in a forward direction. The push button switch  110  may be used to actuate the tractor drive trolley  146  to move the carriage  24  in a reverse direction. 
     A geared rotary limit switch  102  is mechanically connected to gear box  54  and counts the revolutions of the drive shaft  52 . When the limit switch  102  reaches a preselected number of revolutions in either direction an electric signal is transmitted to the electrical control  99  to turn off the motor  46 . Thus the limit switch  102  shuts off the motor  46  when the lifting cable  68  is fully wound on drum  66  or when the lifting cable  57  is fully unwound from drum  66 . 
     In using the present invention, the carriage  24  is moved, for example, to the position shown in  FIG. 1 . The carriage  24  may be moved manually or with a conventional tractor drive trolley  146  as shown in  FIGS. 17-19 . The tarpaulin  86  is positioned underneath carriage  24  as shown in  FIG. 1 . The control switch  98  is then used to activate the motor  46  and drop the lifting cables  68  to the tarpaulin  86 . The cables  68  are then positioned in the tarp connectors  70  as shown in  FIG. 11  and the tarp connectors  70  threaded through “D” rings  84 . The cables  68  are then positioned in the tarp connectors  70  as shown in  FIG. 10  and  FIG. 6 . Next the motor  46  is activated with control switch  98  to wind lifting cable  68  onto drums  66  thus lifting the tarpaulin  86  to a raised portion as shown in  FIG. 2 . A vehicle  88  is then driven underneath the outriggers  23  and  25  as shown in  FIG. 14 . The carriage  24  with the tarpaulin  86  is moved to a position over the trailer payload  90  as shown in  FIG. 15 . The motor  46  is then activated with switch  98  to lower the lifting cables  68  with tarpaulin  86  over the trailer payload  90  as shown in  FIG. 16 . The tarpaulin  86  is then secured to the vehicle  88 . The lifting cables  68  are then positioned in tarp connectors  70  as shown in  FIG. 11 . The motor  46  is activated with switch  98  to wind the cables  68  onto drums  66  thus retracting the cables  68  from the “D” rings  84  of the tarpaulin  86 . When this is completed, the vehicle  88  may be driven away with the tarpaulin  86  fully covering the payload  90 . 
     The vehicle  88  as described above is driven underneath the outriggers  23  and  25  for draping the tarpaulin  86  over the payload  90  as shown in  FIG. 16 . The vehicle  88  may also be driven between the upright posts  12  and  18  and between upright posts  14  and  16  as shown in  FIGS. 18 and 19 . In this case, the tarpaulin  86  may be picked up by the carriage  24  when the carriage  29  is positioned below the outriggers  23  and  25 . 
     A second embodiment of the present invention is shown in  FIGS. 17-19 . In this embodiment a hydraulic drive system is substituted for the electric motor and drive shaft system for rotating the drums  66 . In this embodiment, an electric motor drives a hydraulic pump  114  which pumps hydraulic fluid from reservoir  116  and delivers the hydraulic fluid through line  118  to an electrically operated hydraulic control valve  120 . 
     The solenoid valve  120  in one position is used to direct the hydraulic fluid through the system in one direction for rotating the drums  66  to allow the cable  68  to be dropped downwardly and when solenoid valve  120  is actuated to a second position it is used to direct the hydraulic fluid through the system in the opposite direction for rotating the drums in the opposite direction so as to lift the cable  68  in a manner similar to the first embodiment. The direction of fluid flow in  FIG. 16  is shown with arrows to show the hydraulic fluid flowing in one direction for lifting the cables  68 . When the direction of fluid flow is reversed, the hydraulic system is used for lifting the cables  68 . 
     As shown in  FIG. 16 , the solenoid valve  120  is connected to a line  122  which directs fluid flow to a conventional dual direction relief valve  124 . A line  126  connects the relief valve  124  with a hydraulic motor  128 . The hydraulic motor then drives a first drum  66  in a conventional manner. A return line  130  returns the hydraulic fluid to relief valve  124 . The hydraulic fluid is then directed through line  132  to a relief valve  124  associated with a second drum  66 . The hydraulic fluid similarly is directed through line  126  to hydraulic motor  128  and then through return line  130  to relief valve  124 . The hydraulic fluid is then directed through line  132  to a relief valve  124  and then through line  126  to the hydraulic motor  128  connected to a third drum  66  and then back to the relief valve  124  through line  30  and then to line  134 . Line  134  is connected to a relief valve  124  which is directed as before to a hydraulic motor  128  associated with a fourth drum  66 . Once the fluid is returned to the relief valve  124  the hydraulic fluid is directed through line  132  to a relief valve  124  and to a hydraulic motor  128  associated with a fifth drum  66 . Hydraulic fluid when leaving the relief valve  124  is directed to a line  136  which is turn is connected to a relief valve  124 . The fluid is then transported through line  126  to hydraulic motor  128  connected with a sixth drum  66  and then returned through line  130  to relief valve  124 . The hydraulic fluid is then directed through line  138  back to the solenoid valve  120  and returned to the reservoir  116  through line  140 . 
     As with the first embodiment, the hydraulic system is electrically controlled with a control switch  98  as shown in  FIG. 15 . The control switch  98  is connected to the junction box  96  with control cable  100 . The junction box  96  is electrically connected with cable  142  to the electric motor  112 . The cable  144  connects the junction box  96  with the solenoid valve  120 . 
     A conventional electrically driven tractor drive trolley  146  is used move the carriage  24  on the travel beams  20  and  22  as shown in  FIGS. 17-19 . The tractor drive trolley  146  is electrically connected to the junction box  96  with a cable  148 . The operation of the tractor drive trolley  146  is controlled with the control switch  98  as described above with the first embodiment. 
     The second embodiment is used in the same manner as the first embodiment, the only difference being that a hydraulic system is used for rotating the drums  66  instead of an electric motor  46  and drive shafts. 
     The present invention has particular application when multiple tarpaulins are to be used for covering a payload with the tarpaulins arranged one behind the other on top of the payload. In this situation, the truck is driven underneath the outriggers or between the upright posts and the carriage is moved to a position side by side with the payload to be covered. The cables are dropped and the tarpaulin material connected to the cables. The tarpaulin is then lifted to the overhead position and the carriage moved over the payload to be covered and the tarpaulin then dropped on top of the payload. The carriage is then retracted to the position for picking up another tarp and the truck is driven forward to an extent to allow the second tarp to be used for covering another portion of the payload. The tarp is picked up and then transported by the carriage over the top of the payload and again dropped down on top of the payload. This process can be continued until such time as the entire payload is covered. 
     While the fundamental novel features of the invention have been shown and described, it should be understood that various substitutions, modifications, and variations may be made by those skilled in the arts, without departing from the spirit or scope of the invention. Accordingly, all such modifications or variations are included in the scope of the invention as defined by the following claims: