Retractable cover for a truck body
BACKGROUND OF THE PRESENT INVENTION 
     The present invention relates to devices used for moving a flexible covering between an open and a covering relation to the open top of the load-carrying body of a truck. The necessity for covers of this nature has resulted from local and state regulations which require open top trucks which haul materials such as sand, gravel, land fill, etc. to cover the loads. Loads of this nature have constituted a hazard to following automobiles and motorcyclists due to the fact that the air currents created by rapid movements of the trucks generally result in such materials flying into the following traffic, sometimes resulting in damages such as broken windshields. 
     Various types of cover mechanisms have been developed and patented. However, the widths of most of the covers approximate the widths of the open tops of the dump trucks and as most trucks generally are loaded to their maximum capacity for economic reasons, the resulting hump loads generally draw the covers upwardly, exposing the side edges of the loaded materials. Attempts at solving this problem have resulted in a plurality of the tie-down lines or ropes, fixed in a spaced relation along the two side edges of the cover. The free ends of the tie downs are normally tied to projections along the sides of the truck body. 
     A majority of the truck body covers of this nature, now in use, are convolutely wound on a roller over the cab protector when in a retracted condition. As a result, the covers are transversely sized to the roller widths which are generally sized to the width of the truck body. 
     OBJECTS AND ADVANTAGES OF THE PRESENT INVENTION 
     One of the principal objects of the present invention is to provide a retractable cover for the open top of the load-carrying body of a truck, which when used to cover a load remains in its intended position. 
     Another principal object of this invention is to provide a truck body cover of this nature which includes opposed side skirt portions which overlie a substantial height of the top side edges of the load-carrying body when said cover is in its extended position and remain in place in use. 
     A further object of the instant invention is to provide an improved retractable truck body cover which is movable between an extended position in covering relation to the open top of the load-carrying body of a truck and a retracted position wherein said cover is stacked in accordion fashion over the cab protector forwardly of the open top. 
     Yet another object of the present invention is to provide an improved truck cover device of the type which includes a generally U-shaped frame, pivotally attached at the lower ends of the two leg portions thereof to the respective sides of the truck body and to the rear end of the flexible cover along the length of the transverse base member thereof. Downward projections are provided at the respective ends of the transverse base member to anchor the rear ends of the side skirt portions of the cover. 
     A still further object of this invention is to provide an improved device of the type described which includes drive means, pulley means and connection means, such as ropes or the like, between said pulley means and the base member of the U-shaped frame to retract the cover from its extended position. 
     A further object of the present invention is to provide spring means connecting between said U-shaped frame and the truck body to move the frame and cover from its retracted position to its extended position and which includes an improved cover. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a typical dump truck provided with the retractable cover mechanism of the present invention, the cover being in an extended position; 
     FIG. 2 is a side elevational view similar to FIG. 1 with the cover in a retracted position; 
     FIG. 3 is a top plan view of the truck and associated cover mechanism as seen in FIG. 1; 
     FIG. 4 is a front elevational view of the drive and pulley means of the cover mechanism as seen along the line 4--4 of FIG. 3; and 
     FIG. 5 is a rear elevational view of the truck as seen in FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     With reference to the drawings in which like reference numerals designate like or corresponding parts throughout the various views and with particular reference to FIGS. 1 and 2 a typical dump truck 10 is illustrated which is provided with a retractable cover mechanism 12 for the open top of the load-carrying body 14 thereof. The truck includes a cab portion 16, front and rear wheel assemblies 18 and 20 and a chassis 22. As illustrated, the load-carrying body 14 is comprised of a pair of opposed side walls 24 and 26, a front wall 28, bottom wall 30 and a tailgate 32 which is pivoted at the top for free swinging movement to an open position for dumping purposes. It should be understood that the retractable cover mechanism 12 of the present invention is applicable to trucks other than dump trucks. However, the dump truck is illustrated because it is generally trucks of this type which haul loads which require covering. 
     The cover mechanism 12 includes a flexible cover 34 having a top portion 36, a pair of opposed side skirt portions 38 and 40 and a front portion 42 which wraps downwardly and under the front wall 44 of a platform or cab protector extension 46 of the body 24. Any type of fastening means, illustrated at 48, FIG. 4, may be used to hold the front portion of the cover 42 to the front wall 44. In like manner, the front ends 50 and 52 of the skirt portions 38 and 40 are wrapped around and fastened to vertical downwardly extending members 54 and 56, fixed as by welding to the cab protector 46. In this manner, the entire front portion of the cover 34 is sealed against the wind and air currents during operation of the truck. 
     A transverse shaft 58 is rotatably journaled in a pair of opposed side brackets 60 and 62, fixed to and extending vertically upwardly from the cab protector 46. A pair of pulley members 64 and 66 are fixed to the shaft 58 in a spaced apart relation. As best seen in FIG. 4, a reversible motor 68 and gear reduction box 70 are carried by a platform 72 fixed to the lower end of the bracket 60. The motor 68 is drivingly connected to the transverse shaft 58 as by sprockets 74 and 76 and chain 78. 
     Referring to FIGS. 1, 2 and 5 a generally U-shaped frame 79 comprised of a pair of parallel side legs 80 and 82 and a transverse cross rod 84 connecting between the upper ends thereof, is pivotally connected as at 86 at the lower ends of said legs 80 and 82 to brackets 88 (one side shown) fixed to the load-carrying body 24 intermediate the front and rear ends of each side of said body 14, adjacent the bottom edges thereof. A tension spring 90 is connected between each of the legs 80 and 82 and an arm 92 fixed to and extending vertically upwardly from the rear end of each bracket 88. The U-shaped frame is, therefore, normally urged to the position illustrated in FIG. 1. 
     A pair of flexible cables 94 and 96 fixed at their forward ends to the respective pulleys 64 and 66 extend rearwardly to points of attachment 98 and 100 to the cross rod 84. The flexible cables 94 and 96 pass through pluralities of aligned guide eye brackets 102 and 104 fixed to the top 36 of the flexible cover 34. 
     As best illustrated in FIGS. 1 and 5, the rear end of the cover top 36 is fixed as at 106 to the cross rod 84 and the rear ends of the skirt portions 38 and 40 are fixed as at 108 and 110 to downward projections 112 and 114 fixed to the respective ends of said cross rod 84. In this manner, the normal dumping operation of the truck can be accomplished without retracting the cover. 
     The electric controls for the reversible motor 68 may be located on the motor in a position to be operated by the truck driver without leaving the cab, or they may be remotely located within the cab. An auxiliary crank may be provided for use in event of motor failure or as the lone operating means. 
     In operation, the operator actuates the motor 68 in a first direction permittng the cables 94 and 96 to unwind from the pulleys 64 and 66 whereupon the U-shaped frame 79 under forces created by the tension springs 90 pivots the frame 79 and cover 34 to the covered position of FIG. 1. When the motor 68 is reversed, the cables 94 and 96 are rewound onto the pulleys 64 and 66 causing the U-shaped frame 79 to pivot forwardly, gathering the cover in accordion fashion over and beside the cab protector 46 as seen in FIG. 2. As seen fragmentarily in FIG. 1, flexible ropes, cables or the like 116 are hemmed into the bottom edges of the skirt portions 38 and 40 to tension same when the cover is in the extended position. 
     It will be seen that by reason of the foregoing structure, the elastic cords which are provided in the side hems serve the following purposes: When the cover is in the process of being extended into covering relation of the body, the elastic cords are gradually being drawn taut. Because the cords are in a depending or lower position relative to the tops of the side of the truck, the lower edge of the cover is forced to overlay the outside surfaces of the truck. As a result the operator does not have to climb onto the truck to do this. Also, when it is extended into a covered position, the cords, being stretched out hold the cover against forces blowing from side to side or, indeed, up and down. Further, the cords help to make the cover store in a somewhat smaller package on top of the truck, see for example FIG. 2. Finally, in those situations when it is desirable to tie down the marginal edge of the cover, any depending ties, not shown, along the marginal edge of the cover will fall on the outside of the truck body so that they can be reached and an operator will not have to climb up on the truck, reach over into the truck and pull the tie out and then tie it.