CA1243062A - Truck box tarp arrangement - Google Patents

Abstract

"TRUCK BOX TARP ARRANGEMENT"

ABSTRACT OF THE DISCLOSURE
A tarp arrangement for covering a truck box includes one edge adjustably attached to an edge of the truck box by a plurality of I-bolts adjusted within a flange along the side of the truck box. The other edge of the tarp is attached to a roller leaving a part of the roller bare so that the part can drop over the other side of the truck box just into a plurality of semi-circular half bearings defined by flat plates at right angles to the side of the truck box. The bare roller thus can rotate in the half bearings to tighten the tarp. Move-ment of the tarp is obtained by guide cables rolled up on to the roller in drum sections defined by flanges at the ends of the roller. Each cable is attached to a spring mounted in a vertical tube to take up changes in length and to tension the tarp. In one arrangement the roller is driven by a motor co-axial with the shaft with torque from the motor being communicated through a housing to a track along which the housing runs. The housing includes a torque bar which can be bent in dependence upon the amount of torque with the degree of bending being mea-sured by limit switches which act to halt the motor.

Description

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"TRUCK BOX TARP ARRANGEMENT"

BACKGROUND OF THE INVENTION
This invention relates to a truck box tarp arrangement for covering an open top of a truck box.
It has increasingly become important in recent years to provide a tarp over the open top of a truck box for environmental and safety reasons. In most cases it is necessary for the tarp to be removable and this has conveniently been provided by a roller arrangement in which the edge of the tarp is attached to a roller which can roll across the open top of the truck box from one side to the other to roll up the tarp and uncover the open top.
This general requirement has led to a number of different designs for obtaining the necessary movement of the roller, for latching the roller or the edge of the tarp to the side of the truck box and for controlling the movement of the roller across the truck box.
However, a number of problems have arisen.
Firstly, the various latching arrangements which have been provided tend to engage the tarp itself and provide wear at the contact points which can eventually cause failure of the tarp at or adjacent the roller. Secondly, .. .,-~;~430ti;~

the control of the tarp as it moves across the truck box has been very limited and in a partially open state it is possible for the roller to fall away from the open top.
Furthermore, the proper tensioning of the Karp as it is drawn across the open top has not been effective. In addition, the movement or driving of the roller has gen-erally been obtained by a mechanical crank actuated by the driver at the rear of the truck which is then gener-ally latched in position to the rear of the truck to hold the roller in the open or the closed position.
SUMMARY OF THE INVENTION
It is one object of the present invention, therefore, to provide an improved latching arrangement for the roller of the tarp of this type.
According to the invention, therefore, there is provided a tarp arrangement for covering an open top of an truck box comprising means for attaching one edge of the tarp at one edge of the open top, roller means for attaching along an opposed edge of the tarp so as to leave a portion of the roller bare from the tarp on which the tarp can be rolled and unrolled to uncover and cover the open top, means for rotating said roller and bracket mean6 at an opposed edge of the open top arranged rela-tive to the tarp to define an outwardly facing bearing 3(~t~Z

surface against which the bare roller engages for rota-tion to tension the tarp and latch the roller in the unrolled position of the tarp.
It is a further object of the present invention to provide an improved control arrangement for control-ling the movement of the roller across the truck box to tension the tarp and to provide parallel movement at both ends of the tarp.
According to a second aspect of the invention, therefore, there is provided a tarp arrangement for covering an open top of a truck box comprising means for attaching one edge of the tarp at one edge of the open top, roller means fcr attaching along an opposed edge of the tarp on which the tarp can be rolled and unrolled to uncover and cover the open top, means for rotating said roller, said roller having opposed ends thereof arranged to be exposed from the tarp and each including spaced flange means defining a drum section on the roller separ-ated from the tarp by said flange means and a pair of cable means each having one end attached to the drum section for winding thereon and the other coupled to the box at a position adjacent said opposed edge whereby said cable is unwound as said tarp is rolled and vice versa.
It is a further object of the present invention . . l ~Z43~2 to provide a motor drive arrangement for rotating the roller which is simple and effective.
According to a third aspect of the invention, therefore, there is provided a tarp arrangement for covering an open top of a truck box comprising means for attaching one edge of a tarp at one edge of the open top, roller jeans for attaching along an opposed edgP of the tarp on which the tarp can be rolled and unrolled to uncover and cover the open top, bracket means at an opposed edge of the open top to latch the roller in the unrolled position of the tarp and means for drivingly rotating the roller comprising a motor, means mounting the motor at one end of the roller to rotate the roller and to move with the roller along a side of the box gen-erally at right angles to said edges, housing means for supporting the motor and a track along said wide, said housing includinq runner means for running along said track whereby torque from said motor is communicated to said track.
With the foregoing in view, and other advan-tages as will become apparent to those skilled in the art to which this invention relates as this speciflcation proceeds, the invention i8 herein described by reference to the accompanying drawings forming a part hereof, which ~Z43~

includes a description of the best mode known to the applicant and of the preferred typical embodiment of the principles of the present invention, in which:
DESCRIPTION OF THE DRAWINGS
Figure 1 is a front elevational view of a truck box including a tarp arrangement according to the present invention actuated by an electric drive motor.
Figure 2 is a cross sectional view on an in-creased scale of the top right hand corner of the truck box of Figure 1 showing the roller in a latched posi-tion.
Figure 3 is a cross sectional view of the top left hand corner of the truck box of Figure 1 showing the tarp in a rolled position.
Figure 4 is a side elevational view of the tarp arrangement of Figure 1 in the latched position.
Figure 5 is a front elevational view on an enlarged scale of the motor and housing of the tarp arrangement of Figure 1 with a part of the cover re-moved.
Figure 6 and 7 are front elevational and side elevational views of a tarp arrangement similar to that illustrated in Figures 1 through 5 but showing a manually operable mechanism for rotating the roller.

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In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
A truck box as shown in Figures 1 and 4 is of conventional form including a side 10 and a front 11, the latter including a gable end 12 of slightly arched shape.
The truck box is thus substantially rectangular with a rectangular open top generally indicated at 13. The gable end 12 which is provided at the front and a second gable end 14 provided a the rear both provide a flange 15 which over lies a part of the open top for receiving a reinforced edga 16 of a tarp 17.
One edge of the tarp 17 at the left hand side as shown in Figure 1 and shown in more detail in Figure 3 it attached to a bar 18 running along the length of the tarp edge with the tarp wrapped back around the bar 18 to define a reinforced edge for attachment to a plurality of bolts 19 spaced along the length of the tarp. Each of the bolts passes through an opening in the bar 18 and clamp an I-bolt 20 to the bar via a nut 21 on the outer edge of the bolt 19. The bolt 19 is separate from a box section 22 defining the edge of the truck box so that the edge of the tarp and the bar 18 can merely hang over the top left hand edge of the truck box.

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Each of the I-bolts 20 is clamped to a flange 23 running along the length of the side of the truck box and attached thereof for example by welding at 24. Thus a pair of nuts 25, 26 position the I-bolt relative to the flange 23 so the top of the I-bolt can be adjusted up-wardly and downwardly by moving the nuts 25, 26.
A plurality of straps or support struts 27 are mounted along the length of the side of the truck box by welding to the flange 23. Each of the straps 27 passes outwardly of the bar 18 and the outer edge of the tarp 17 at a position intermediate one of the I-bolts 20 so as to extend upwardly beyond the edge 22 of the truck box to support the tarp 17 in the rolled condition shown in Figure 3.
The opposite edge of the tarp 17 is attached by pop rivets 28 to a roller 29 thus leaving the majority of the roller 29 bare and free from the tarp edge 17. As shown in Figure 2, when fully unrolled, the tarp lies across the full width of the open top 13 of the truck box leaving the roller 29 hanging over one edge of the truck box defined by the frame section 30. A shown in Figure 3 the tarp can be rolled up onto the roller from the fully unrolled position shown in Figure 2 to a fully rolled position shown in Figure 3 with an intermediate position shown in Figure 1.
Turning now to Figure 4, the roller 29 has at each end a portion extending beyond the reinforced edge 16 of the tarp including a pair of spaced flanges 31 and 32 defining between them a drum section 33. The drum section 33 carries a cable 34 with one end of the cable attached to the drum section so as to be wound thereon as the roller is rotated.
The other end of the cable 34 is attached to a spring 35 mounted within a vertical tube 36 attached to the side of the truck box by support straps 37. The tube is arranged as shown in Figure 4 in alignment with the drum 33 so that one tube is provided at the front end of the truck box and a second tube is provided at the rear end of the truck box to co-operate with the respective drum sections. Each of the tubes carries on spaced flan-ges 38 a pulley 39 for guiding the cable out of the tube onto the respective drum 33. A stop 40 in the form of a collar surrounding the cable it mounted on the cable 34 at the inter-connection thereof with the spring 35 so as to prevent the cable end being drawn out of the tube by engagi~lg the edge of the pulley 39 80 as to jam relative to the pulley within the tube.
Rotation of the roller 29 as shown in Figure 1 ~24~

g in an anti-clockwise direction, therefore, will act to roll up the tarp 17 onto the roller while the cables 34 are unwound from the respective drum sections 33. The spring 35 acts to provide a tension in each of the cables so as to maintain the roller pulled toward the tube 3~ as far as possible so that the tarp 17 remains taught or 'ensioned while it is being wound. The spring also acts to take up and release movement of the end of thy cable caused by varying diameters on the roller during windi.ng and unwinding of the tarp and the cable.
Rotation of the shaft 29 in a clockwise direc-tion of course acts to wind up the cable 34 thus unrol-ling the tarp across the open top 13.
The provision of the two drum sections 33 at the ends of the roller 29 causes tensioning of the roller at both endg and thus proper parallel movement of the roller across the truck box. Furthermore, the tarp is properly tensioned at both ends and thus remains square to the truck box without any wrinkles. The inner flanges 31 run immediately adjacent the respective end of the truck box and thus further avoid any twisting of the roller 29 on the truck box. Furthermore, should the truck box be tilted while the roller i8 in an intermedi-ate position as shown for example in Figure 1, the flange lZ~3~

31 at the front end of the truck box in co-operation with the tension in the tarp and the cable acts to retain the roller properly positioned at the intermediate position without any danger of the roller slipping rearwardly along the tilted truck box.
A latching mechanism is shown in Figures 1 and

2 at the right hand top corner of the truck box for re-ceiving the roller 29. The latching mechanism comprises a plurality of bracket members 40 each of which is formed from a flat relatively thin plate and is attached to the side of the truck box so that the plate section stands out at right angles to thy side of the truck box. For this purpose each plate is welded to a flange 41 exten-ding along the length of the truck box. Each plate 40 is generally rectangular in shape with a bearing recess 42 cut in an outer edge thereof so as to face directly out-wardly to the side of the truck box. The recess is semi-circular in shape with the recesses of each of the brackets or plates being co-axial and of the same diame-ter as the roller 29. Thug as shown in Figure 2 when the roller 29 drops over the front edge of the flange 41, it can fall into the bearing defined by the recesses 42 of the plates 40.
Further rotation of the roller 29 in a clock-~43~iX

wise direction as shown in Figure 2 acts to further ten-sion the tarp 17 while the roller 29 rotates in the bear-ing defined by the brackets 40.
It will be noted that the recess or bearing defined by the recesses 42 faces directly outwardly from the side of the truck box and does not include any por-tions inclined outwardly and downwardly from the side of the truck box. The roller 29 is held in position within the recesses by the tension in the tarp 17. The fact that the roller 29 can rotate within the recesses 42 of the plates 40 provides metal to metal contact between the roller and the plates so thaw further rotation can con-tinue without binding. Thus the plates 40 effectively provide half bearings for the roller 29. This ready rotation of the roller 29 allows greater tensioning of the tarp 17 and at the same time avoids any rubbing of the tarp 17 at the latch so a to avoid wear of the tarp by rubbing contact with any metal surfaces.
Rotation of the roller 29 i 9 obtained by a drive motor 43 which is preferably electric and driven by power from the truck electrical system. The necessary wiring is omitted for the convenience of lllustration.
The motor 43 is mounted in a housing generally indicated at 44 providing a circular support for the motor substan-~LZ43~i2 tially co-axial with the shaft 29. A gear box schemati-cally indicated at 45 communicates drive from the motor 43 to the shaft 29, the gear box preferably being a plan-etary type gear providing a high reduction so that rapid rotation of the motor 43 obtains relatively slow movement of the shaft so the necessary torque can be obtained without necessity for a high power motor. A shear pin 451 is coupled between the gear box and roller to prevent damage or excessive torque.
The housing 44 is shown in more detail in Figure 5 and includes an arched upper section 46 housing the gear box 45. The arched upper section 46 is attached to a transverse beam 47 thus rigidly surrounding the gear box and coupled thereto so that torque from the motor is immediately communicated to the arched section 46 and the beam 47. The beam 47 is welded to a torque bar 48 which extends outwardly therefrom at right angles. A housing section 49 is rigidly attached to the arched portion 46 and to the beam 47 and includes a back plate 50 and a pair of upstanding walls 51. The back plate 50 supports a pair of stops 52 in the form of a lug 53 and an adjust-able bolt 54. ln addition, the back plate supports a pair of micro sw1tcheg 55, 56 arranged on respective sides of the torque bar 48. A cover 57 shown in Figure 1 ~LZ~ 2 but omitted in Figure 5 over lies the micro switches 55, 56 and is attached to the upstanding walls 51 of the section 49.
The torque bar 48 is at its end remote from the motor attached by a pivot coupling 58 to a connecting bar S9. The pivot coupling 58 allows the torque bar 48 to rotate around the connecting bar 59 about an axis at right angles to the latter. The bar 59 carries a pair of collars 60 each of which surrounds a portion of a track 61 mounted on the front wall of the truck box as shown in Figures 1 and 4. The collars are spaced apart by the length of the bar 59 so that can freely run along the track 61 which includes a horizontal section 62 and a substantially vertical section 63 inter-connected by a curved portion 64 which is shaped relative to the collars 60 to allow the collars to run around the curved section from the position shown in Figure 1 to a position in which the bar 59 is ~ub~tantially vertical and parallel to the section 63 of the track.
The distance between the pivot 58 and the axis of the motor 43 is greater than the distance between the track and the edge of the truck box on which the roller 29 runs 80 that the bar 48 lies at an angle to the track as shown in Figure 1. This angle changes as the shaft 29 ~436~

runs up the gable end 12 and then runs down for a posi-tion in which the bar 48 is almost horizontal to a posi-tion in which it lies at approximately 45 degrees. The torque from the motor 43 communicated to the upper hous-ing section provided by the beams 46 and 47 is transmit-ted from the motor to the track by the torque bar 48.
The bar 48 is of a dimension such that it can bend under the application of torque with of course the degree of bending varying with the amount of torque applied. As the bar 48 bends the position of the stops ~2 and the limit switches 55 moves relative to the bar 48 as these are rigidly mounted to the housing relative to which the bar bends.
As the motor 43 therefore drives the roller from the position shown in Figure 1 to the position shown in Figure 3, the runner defined by the collars 60 ana the bar 59 moves along the track toward the left hand end thereof until the roller and tarp engage the straps 27.
In this position the torque from the motor increases against the rigid stop provided by the straps 27 thus further bending the bar 48 until the micro switch 56 is actuated. This can be used to stop the motor 43 to pre-vent damage and to locate the roller and tarp in the fully opened position. Similarly as the roller is rota-~243(~2 ted in a clockwise direction as shown in Figure 1, therunner moves towards the right hand end of the track around the bend 64 and down the portion 63 until the shaft reaches the end of the open top and latches into the brackets 40. In this position again the torque is substantially increased and the limit switch 55 is actu-ated by the bending of the bar 48. This can again be used to halt the motor 43 to prevent damage and to locate the shaft in the latched position.
The track shown in Figure 1 includes a substan-tially horizontal section 62 but in an alternative arrangement (not shown) the track can in fact substan-tially follow the angle of the gable end so it reaches a peak at a position corresponding to the gable end.
The adjustment provided by the I~bolts 20 can accommodate stretching of the tarp to ensure that the edge of the tarp terminates at the desired position rela-tive to the brackets 40. The adjustment can also accom-modate twisting of the truck box which can occur due to damage or misuse so the tarp runs accurately and properly parallel relative to the gamble ends 12.
Turning now to Figure 6, an arrangement i8 shown in which the electric motor is omitted and a manual actuation for the rotation of the roller 29 is provided.

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Specific to the manual actuation comprises a lever 70 which can be rotated manually to drive rotation of thy roller 29 through a universal joint 71. This is a con-ventional arrangement.
However, instead of using a conventional arrangement in which the lever 70 is latched to provide tensioning of the roller 29, this tensioning is provided by a latch 72 welded at the required location on a disc 73 on the end of the roller 29. The latch 72 co-operates with a loop 74 which is pivotly mounted on a plate 75 and biased upwardly by a spring 76. The latch 72 thus when the roller 29 has been rotated to the required position engages the loop 74 to hold the disc 73 against rotation in an ahti-clockwise direction to release tension in the tarp. The loop can however be actuated by a push rod 77 to release the latch 72 when it is required to unroll the tarp as previously explained. Thus the latch and loop 72, 74 avoids the necessity for locating the crank or lever 70 at a required position and automatically locates the roller 29 at the required position for properly ten-sioning the tarp.
Since various modifications can be made in my invention a hereinabove described, and many apparently widely different embodiments of same made within the ~Z43~

spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

Claims

(1) A tarp arrangement for covering an open top of an truck box comprising means for attaching one edge of the tarp at one edge of the open top, roller means for attaching along an opposed edge of the tarp so as to leave a portion of the roller bare from the top on which the tarp can be rolled and unrolled to uncover and cover the open top, means for rotating said roller and a plurality of bracket members at an opposed edge of the open top in spaced relation therealong each bracket member comprising a flat vertical plate arranged relative to the tarp to define an outwardly facing substantially semi-circular bearing recess in one edge of the plate against which the bare roller engages for rotation to tension the tarp and latch the roller in the unrolled position of the tarp.
(2) The invention according to claim 1 where-in said means for attaching said one edge of the tarp at said one edge of the open top includes means for adjust-ing the position of said one edge of the tarp relative to said one edge of the open top.
(3) The invention according to claim 2 where-in said adjusting means includes a plurality of I-bolts attached to said top edge and flange means on said truck box at a position below said one edge thereof whereby the I-bolts can be adjusted in position relative to said flange by nuts thereon.
(4) The invention according to claim 1 where-in said roller includes opposed ends thereof arranged to be exposed from the tarp and spaced flange means on each end defining a drum section of the roller separated from the tarp by said flange means, wherein there is provided a pair of cable means each having one end attached to the drum section for winding thereon and another end thereof coupled to the box at a position adjacent to said opposed edge whereby said cable is unwound as said tarp is rolled and vice versa.
(5) The invention according to claim 4 where-in said other end of the cable is attached to spring means secured within a tube mounted on a side of the box whereby said other end of the cable is movable within the tube relative to the side to tension the tarp and to take up variations in length caused by said winding and rol-ling.
(6) The invention according to claim 5 where-in said tube is substantially vertical.
(7) The invention according to claim 5 including pulley means at the end of the tube from which the cable emerges.
(B) The invention according to claim 7 in-cluding a stop on the cable for engaging the pulley to prevent withdrawal of the cable from the tube beyond the stop.
(9) The invention according to claim 1 where-in said means for rotating said roller comprises a motor, means mounting the motor at one end of the roller to rotate the roller and to move with the roller along a side of the truck box generally at right angles to said edges, housing means for supporting the motor and a track along said side, said housing including runner means for running along said track whereby torque from said motor is communicated to said track.
(10) The invention according to claim 9 wherein the track includes a substantially horizontal portion across said side and a substantially vertical portion at an end of said side adjacent said opposed edge.
(11) The invention according to claim 9 wherein the extent of the housing between said runner means and said roller is greater than the distance be-tween said track and said top whereby the housing runs along said track inclined at an angle relative thereto.

(12) The invention according to claim 9 wherein the housing is attached to said runner means by torque means movable in accordance with the torque appli-ed to said track by said motor and wherein there are provided limit switch means for stopping said motor when said torque and therefore said movement exceeds a pre-determined maximum.
(13) The invention according to claim 12 in-cluding means for physically engaging and halting move-ment of said roller and said rolled tarp at said one edge and means for physically engaging said roller at said opposed edge whereby said limit switch means indicates said roller reaching either of said edges.
(14) The invention according to claim 12 or 13 wherein the torque means comprises a bar inter-connecting said housing to said runner means and bendable in accor-dance with the torque applied thereto by said motor.
(15) The invention according to claim 9, 10 or 11 wherein the runner means comprises a pair of spaced collars each wrapped around said track and inter-connected by strut generally longitudinal of said track.
(16) The invention according to claim 9, 10 or 11 including shear pin means inter- connecting said motor and said roller whereby said shear pin can shear on application of excess torque by said motor to said roller.
(17) A tarp arrangement for covering an open top of a truck box comprising means for attaching one edge of a tarp at one edge of the open top, roller means for attaching along an opposed edge of the tarp on which the tarp can be rolled and unrolled to uncover and cover the open top, bracket means at an opposed edge of the open top to latch the roller in the unrolled position of the tarp and means for drivingly rotating the roller comprising a motor, means mounting the motor at one end of the roller to rotate the roller and to move with the roller along a side of the box generally at right angles to said edges, housing means for supporting the motor and a track along said side, said housing including runner means for running along said track whereby torque from said motor is communicated to said track.
(18) The invention according to claim 17 wherein the track includes a substantially horizontal portion across said side and a substantially vertical portion at an end of said side adjacent said opposed edge.
(19) The invention according to claim 17 wherein the extent of the housing between said runner means and said roller is greater than the distance be-tween said track and said top whereby the housing runs along said track inclined at an angle relative thereto.
(20) The invention according to claim 17 wherein the housing is attached to said runner means by torque means movable in accordance with the torque appli-ed to said track by said motor and wherein there are provided limits to which means for stopping said motor when said torque and therefore said movement exceeds a pre-determined maximum.
(21) The invention according to claim 20 in-cluding means for physically engaging and halting move-ment of said roller and said rolled tarp at said one edge and means for physically engaging said roller at said opposed edge whereby said limits to which means indicates said roller reaching either of said edges.
(22) The invention according to claim 20 or 21 wherein the torque means comprises a bar inter-connecting said housing to said runner means and a bendable in accordance with the torque applied thereto by said motor.
(23) The invention according to claim 17, 18 or 19 wherein the runner means comprises a pair of spaced collars each wrapped around said track and inter-connected by strut generally longitudinal of said track.
(24) The invention according to claim 17, 18 or 19 including shear pin means inter-connecting said motor and said roller whereby said shear pin can shear on application of excess torque by said motor to said roller.