Abstract:
A method and apparatus for placing a protective sheet over a load. The apparatus includes a chassis having outer and inner wheels adapted to allow the chassis to traverse along a horizontal path of motion. A mandrel support beam is attached to the chassis adjacent its inner end, the outer end extending beyond the chassis with its longitudinal axis being substantially perpendicular to the horizontal path of motion of the chassis. A mandrel is rotatably attached to the chassis, the outer end of the mandrel being rotatably supported by the mandrel support beam. At least one of the inner wheels of the chassis is in contact with the mandrel adjacent its inner end in a manner adapted to cause the mandrel to rotate upon rotation of the wheel. Pockets located along the mandrel allow the sheet to be releasably attached for winding up onto the mandrel.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a method and apparatus for placing a tarpaulin over a load, such as one carried by a truck, semi-trailer or other land or water load transportation vehicle, or a load stacked on a floor or the ground. 
   Operators of trucks or semi-trailers often protect a load being transported by covering the load with a tarpaulin. Installing the tarpaulin usually involves having a person climb to the top of the load and drag the tarpaulin over the load. Such a procedure is dangerous since the installer may fall to the ground, resulting in serious injury or death. 
   It has been suggested to use a device called a Barney&#39;s Beam. This device is a horizontal beam attached to a frame. One end of the tarpaulin is attached to the beam and frame on the ground, the beam and frame lifted with a forklift to a height above the load, the beam and frame advanced along the side of the truck to pull the tarpaulin over the load, and the tarpaulin tied down from the ground. Such a procedure can cause damage to the tarpaulin and/or load. 
   U.S. Pat. No. 6,634,850 describes a truck/trailer tarping device. This device can be mounted on the forks of a forklift and includes a tray portion and a plurality of wheels that can be rotated clockwise or counterclockwise by means of drive system. A tarp is placed between the wheels and the tray portion, and rotated in a direction to pull the tarp onto the tray, as best seen in  FIGS. 11A-11C . The device is then moved by the forklift to a position over the load to be covered (as seen in  FIG. 11D ), and the wheels rotated in a direction to unroll the tarp over the load. This device is complicated. 
   SUMMARY OF THE INVENTION 
   The present invention is a device for placing a protective sheet material, such as a tarpaulin, over a load without requiring a worker to climb on top of the load, and which is easy to use. The load to be covered can be one carried by a flat-bed truck, semi-trailer, or other land or water transportation vehicle, or it can be a load stacked on a floor or the ground. 
   The device has a chassis to which a horizontal mandrel is rotatably attached. A mandrel support beam is attached to the chassis above the mandrel, and the outer end thereof has a downwardly extending leg to which the outer end of the mandrel is rotatably attached. 
   The chassis has two outer wheels and two inner wheels. The inner wheels rotatably engage the inner end of the mandrel. 
   The chassis has forklift receiving tubes to allow the forks of a forklift to be inserted to move and raise the device. 
   In use a tarpaulin is laid out on the ground and has its side portions double folded back onto the main body portion. The forklift driver maneuvers the mandrel over the tarpaulin end opposite the tarpaulin end flap, and that end is removably attached to the mandrel by means of aligned “pockets” located along the length of the mandrel. 
   The forklift is then moved towards the unattached end (the end containing the end flap) which causes the inner and outer wheels of the device to rotate. Rotation of the inner wheels causes the mandrel to rotate and wind up the tarpaulin onto the mandrel. Winding is stopped when the juncture of the end flap to the main body portion of the tarpaulin is reached. No motor is required to rotate the mandrel. 
   The wound up tarpaulin is then moved to the loaded truck/trailer, raised to a height above the height of the load on the truck/trailer, and the end flap portion attached to the load or truck/trailer. The forklift then moves along the load, unwinding the tarpaulin as it moves forward. The end of the tarpaulin releases itself from the mandrel, and the sides of the tarpaulin are then attached to the bed of the truck/trailer in the usual manner. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front elevation view of the tarpaulin placement device of the present invention; 
       FIG. 2  is a top plan view of the device; 
       FIG. 3  is a front elevation view of the chassis of the device; 
       FIG. 4  is a top plan view of the chassis of the device; 
       FIG. 5  is a right side elevation view of the chassis of the device 
       FIG. 6  is a right side elevation view of one of the mandrel holder beam stanchions; 
       FIG. 7  is a right side elevation view of the mandrel holder beam held by a U-shaped clamping member; 
       FIG. 8  is a partial front elevation view of the mandrel and an attached pocket; 
       FIG. 9  is a right side elevation view of the mandrel and an attached pocket taken along line  9 - 9  of  FIG. 8 ; 
       FIG. 10  is a top plan view of an unrolled tarpaulin; 
       FIG. 11  is a front elevation view of an unrolled tarpaulin with its side flaps double folded inwardly; and 
       FIG. 12  is a side view of a tarpaulin being releasably fastened to the mandrel of the device preparatory to being rolled up onto the mandrel. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   The tarpaulin placement device  10  includes a chassis  20 , a cylindrical mandrel support beam  50 , and a cylindrical rotatable mandrel  70 . 
   As best seen in  FIGS. 3 and 4 , chassis  20  includes right and left end frame members  22  and  24 , front and rear cross frame members  26  and  28 , and central cross frame member  30 . 
   Right front and right rear wheels  32  and  32 ′ are rotatably attached to right end frame member  22  by axles  34  and  34 ′. Left front and left rear wheels  36  and  36 ′ are rotatably attached to left end frame member  24  by axles  38  and  38 ′. Right front and right rear wheels  32  and  32 ′ are located adjacent the front and rear ends, respectively, of right end frame member  22 . Left front and left rear wheels  36  and  36 ′ are located in a front and rear mid-portion of left end frame member  24 , and are spaced apart a distance adapted to allow mandrel  70  to abut the upper portions of wheels  36 ,  36 ′, and to cause mandrel  70 ′ to be rotated by rotation of the wheels  36 ,  36 ′. 
   Wheels  32 ,  32 ′,  36 , and  36 ′ allow chassis  20  to be moved along a horizontal path of motion. 
   Although two right wheels  32 ,  32 ′ and two left wheels  36 ,  36 ′ are shown, one or more additional wheels can be located on the right and/or left sides of chassis  20 . 
   Right and left fork lift tubes  40  and  42  are attached to the undersides of front and rear cross frame members  26  and  28 , and central cross frame member  30 , such as by welding. Right and left fork lift tubes  40  and  42  are generally rectangular in cross-section, and adapted to receive the forks of a fork lift from either the front or rear. 
   A counterbalancing weight mass  44  is positioned onto floor portions  45 ,  45 ′ on the right side of chassis  20 , and secured thereto by any suitable means, such as front and rear end dams  46 ,  46 ′. Counterbalancing weight mass  44  can be a single block of material or built up of slabs of material (as shown in  FIG. 5 ). The weight of counterbalancing weight mass  44  is selected to prevent device  10  from tipping over due to the leveraged weight of those portions of mandrel support beam  50  and mandrel  70  that extend beyond chassis  20  and the weight of the tarpaulin  80  wound up onto the mandrel  70 . 
   Mandrel support beam  50  is supported on chassis  20  by right and left stanchions  52 A and  52 B, central stanchion  52 C, cross-beam  58  and flanged clamp members  60 A and  60 B. Although it is preferred that mandrel support beam  50  have a cylindrical cross-section, other beam shapes could be used. Whatever its shape, mandrel support beam  50  is preferably hollow to minimize its weight. 
   Right stanchion  52 A is shown in  FIG. 6 , and includes vertical column  54 , and front and rear angled struts  56  and  56 ′. The bottom ends of vertical column  54  and front and rear angled struts  56  and  56 ′ are attached to the upper surfaces of cross frame members  26 ,  28  and  30  of chassis  20 , such as by welding. Left stanchion  52 B and central stanchion  52 C are substantially identical to right stanchion  52 A. However, central stanchion  52 C is preferably taller than right stanchion  52 A, and left stanchion  52 B is preferably taller than central stanchion  52 C, as shown in  FIG. 3 , to impart an appropriate camber to mandrel support beam  50 . 
   A cross-beam  58  extends across the tops of stanchions  52 A,  52 B, and  52 C, and is attached to the top of the vertical columns  54  thereof, such as by welding. 
   U-shaped flanged clamp member  60 A is attached to the upper surface of cross-beam  58  adjacent right stanchion  52 A, such as by welding. Similarly, U-shaped flanged clamp member  60 B is attached to the upper surface of cross-beam  58  adjacent left stanchion  52 B, such as by welding. Bolt holes  63  pass through the flange portions of clamp members  60 A and  60 B, and bolt holes  163  pass through the flange portions of mating inverse clamp members  160 A and  160 B. 
   The inner (right) end portion of cylindrical mandrel support beam  50  is placed into the cradles formed by U-shaped flanged clamping members  60 A and  60 B. Mating right and left inverse U-shaped flanged clamping members  160 A and  160 B are placed over cylindrical mandrel support beam  50  and into contact with flanged clamping members  60 A and  60 B, respectively. The bolt holes  63  located in the flanges of flanged clamp member  60 A and the bolt holes  163  located in the flanges of flanged clamp member  160 A are positioned into alignment. Similarly, the bolt holes  63  located in the flanges of flanged clamp member  60 B and the bolt holes  163  located in the flanges of flanged clamp member  160 B are positioned into alignment. Front and rear bolts  61  and  61 ′ are passed through the holes  63 ,  163  of inverse flanged clamp member  160 A and holes  63 ,  163  of flanged clamp member  60 A, and secured with front and rear nuts  65  and  65 ′. Similarly, front and rear bolts  61  and  61 ′ are passed through the holes  63 ,  163  of inverse flanged clamp member  160 B and holes  63 ,  163  of flanged clamp member  60 B, and secured with front and rear nuts  65  and  65 ′. The outer end of cylindrical mandrel support beam  50  extends beyond chassis  20  substantially the same distance as the outer end of mandrel  70 . 
   A leg  52  extends vertically downward from the outer (left) end of support beam  50 , and has an opening therein (which can be journalled) to receive a stub axle  72  extending outwardly from the outer (left) end of mandrel  70 . The inner (right) end of mandrel  70  rests against the upper portions of both of left, inner wheels  36  and  36 ′ of chassis  20 . 
   A plurality of aligned pocket members  74  are positioned along the length of mandrel  70  and attached thereto. As best seen in  FIGS. 8 and 9 , each pocket member  74  includes front and rear angled arms  76 ,  76 ′ which form recesses  78 ,  78 ′ for receiving and holding end  85  of tarpaulin  80 . 
   In use, a tarpaulin  80  having an end flap  82  with a trailing edge  84 , leading edge  85 , and right and left side flaps  86  and  86 ′ is spread out on the ground, as shown in  FIG. 10 . The right and left side flaps  86  and  86 ′ are double folded inwardly in an overlapping S-shape manner so that the width of the main body of the tarpaulin  80  becomes substantially the same as the width of the end flap  82 , as best seen in  FIG. 11 . Tarpaulin  80  may be formed of any flexible sheet material suitable for covering and protecting a product. 
   The forks of a forklift (not shown) are inserted into forklift tubes  40  and  42 . Safety chains (not shown) are attached to eyebolts  67 A and  67 B, and to the forklift. 
   The forks of the forklift can be inserted into either end of the forklift tubes  40 ,  42 . When the forklift is to move forward to wind up tarpaulin  80 , the left fork would be inserted into the right forklift tube  40  and the right fork would be inserted into the left forklift tube  42 . If the forklift is to move in reverse to wind up tarpaulin  80 , the right fork would be inserted into the right forklift tube  40  and the left fork would be inserted into the left forklift tube  42 . The choice of whether to move the forklift in forward or in reverse during winding up of tarpaulin  80  depends on which side of the truck or trailer it is desired to locate the forklift during unwinding and positioning of the tarpaulin  80 . 
   In the illustration of winding up tarpaulin  80  shown in  FIG. 12 , the forklift would be moving in a forward or reverse direction in the direction indicated by arrow A. The mandrel  70  is positioned over the end  85  of tarpaulin  80  opposite to end flap  82 , and the end  85  stuffed into the recesses  78  of pocket members  74 . The forklift is then moved in the direction shown by arrow A in  FIG. 10 . Inner wheels  36  and  36 ′ rotate in the direction shown by the arrows adjacent thereto, which causes mandrel  70  to rotate in the direction shown by the arrow adjacent thereto. The tarpaulin  80  is wound up onto mandrel  70  until the juncture of the main body portion of the tarpaulin and its end flap  82  is reached. The positioning device  10  is then elevated by the forklift to a height sufficient to prevent end flap  82  from dragging on the ground. The positioning device  10  is then moved by the forklift to the end of the load to be tarped. The positioning device  10  is then raised about one foot above the load and the end flap  82  attached to the load or truck/trailer in a manner known in the art. The positioning device  10  is then moved along the load to unwind tarpaulin  80  over the top of the load. The side flaps  86 ,  86 ′ will typically fall down around the side of the load, or, if not, can be manually lowered. The side flaps  86 ,  86 ′ are then fastened to the load or truck/trailer in a manner known in the art. If necessary, a pole can be used to move the end flap  82  or side flaps  86 ,  86 ′ to their desired location. 
   The use of the descriptors “right”, “left”, “front”, “rear”, “inner” and “outer” have been used merely in order to differentiate various elements, and are not to be construed as absolute directions. 
   It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.