System for covering the bed and box of a pick-up truck, wagon or trailer

A system for covering the box and bed of a pick-up truck includes a tarp, a pair of side rails, an end rail and a cam latch associated with each side rail. The tarp includes beads associated with its edges. These beads cooperate with slots in the rails to fix the edges of the tarp to the rails. The cam latches are provided to interact with the end rail to stretch the tarp and help secure it in place over the bed and box of the pick-up truck.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a system for covering an opening in a 
detachable manner. More specifically, the present invention relates to a 
system for detachably covering the bed and box of a pick-up truck or 
trailer. 
2. Description of the Prior Art 
Since before the advent of the motorized truck, people have understood the 
need to cover items as the items are transported to protect them from the 
elements. Generally, when such items are being transported on the bed of a 
wagon, trailer or truck, this has been accomplished using a tarp. To 
provide adequate protection, the tarp should be fixed in place along the 
entire perimeter of the box. The tarp should also be taut and remain so to 
prevent it from sagging and collecting water or debris. Thus, some 
reliable means of holding the tarp in place is required to provide 
effective protection. In the days of the pioneers who explored this 
continent, ropes were used to hold tarps in place. A variety of fasteners 
for holding tarps in place have been developed since that time. Fasteners 
in common use today include bungie cords, hook-and-loop type fasteners, 
grommets and rope arrangements, various types of snaps, and various types 
of clips. 
One cover arrangement which incorporates a number of different fasteners 
for securing a tarp in place is disclosed in U.S. Pat. No. 5,174,353 dated 
Dec. 29, 1992 to Schmeichel et al. The cover arrangement disclosed in this 
patent, for example, includes a tarp and hook-and-loop type fasteners to 
attach to the sides of the tarp and the sides of a truck box. This patent 
also discloses an L-shaped plate which cooperates with various cord 
members, stops, lips and locks to secure the back end of the tarp in 
place. This patent also recognizes the difficulty associated with using 
hook-and-loop type fasteners. Rather than using a different type of 
fastener, the patent suggests the use of plastic members attached to the 
tarp to prevent the two elements of the hook-and-loop type fastener from 
engaging each other as the tarp is rolled and unrolled. 
Despite the many attempts made in the prior art to provide a simple, 
inexpensive and durable cover that can be easily and quickly opened and 
closed, the need for such a cover continues to exist. The present 
invention fills this need and solves the problems associated with prior 
art covers outlined above. 
SUMMARY OF THE INVENTION 
The present invention relates to a system for covering the box and bed of a 
truck, wagon or trailer. The system includes a frame. The frame includes a 
pair of side rails. Each side rail is fixed to the top edge of one of the 
sides of the box. The side rails have a front end, a rear end, and an 
outer channel that runs the length of the rail. Fixed to the rear end of 
each rail is a cam latch. The frame also includes a front rail and a back 
rail. The front rail is attached to the top edge of the front of the box. 
The system also includes a tarp. The tarp has a front edge, a back edge, 
and a pair of side edges. A bead projects downwardly along the length of 
each side edge of the tarp. The front edge of the tarp is attached to the 
front rail of the frame. The back edge of the tarp is attached to the back 
rail of the frame. This arrangement fixes the front of the tarp to the 
front of the box. It also allows the back rail to be used as a spindle 
about which the remainder of the tarp can be rolled and unrolled. 
The tarp is easily secured in the covered position. The tarp is unrolled. 
The ends of the back rail are then placed in contact with the two cam 
latches. The levers of the cam latches are rotated to engage the ends of 
the back rail to tighten the tarp and lock it in place. To create a 
water-tight seal along the edges, the beads on the tarp are pushed into 
the outer channels of the side rails. 
The principle object of the present invention is to provide a truck bed and 
box cover which is easily opened and closed. 
Another object of the present invention is to provide such a cover that can 
be secured in place and left partially open or partially opened to gain 
access to the interior of the box. 
Another object of the invention is to provide such a cover which is durable 
and stretched tight when closed. 
Still another object of the invention is to provide a cam lock that serves 
to stretch the cover tight. 
A further object of the invention is to provide a quick means for securing 
the sides of the cover to the rails to create a seal along the sides of 
the cover. 
These and other advantages of the present invention will become more clear 
from a reading of the detailed description of the invention in conjunction 
with the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 and 2 show a cover 10 consisting of a flexible, durable, 
stretchable tarp 12 and a frame 40. The tarp 12 is preferably made of a 
water-resistant material or treated to make it water resistant. The tarp 
12 has a front edge 14, a pair of side edges 16 and 18, and a back edge 
20. Running along and adjacent to each of the side edges 16 and 18 are 
flexible, compressible beads 24. The flexible beads 24 are preferably 
tapered and about 3/8 of an inch wide at their widest point. The beads 24 
are preferably made of an extruded plastic material created from polyvinyl 
chloride and a tri(2-ethylhexyl) trimellitate plasticizer. As shown in 
FIG. 4, a cross section of each bead 24 has an arrow-shape defined by a 
head 80 having a base 82 coupled to a shaft 84. The beads also preferably 
have a hollow core 86. 
The frame 40 includes a front rail 42, a pair of side rails 46, and a back 
rail 48. The front rail 42 is fixed to the top of the front wall of a 
vehicle box. The side rails 46 are fixed to the top of the opposing side 
walls of the vehicle box. As shown in FIG. 3, the rails 46 each include a 
bottom member 50, an upright center member 52 projecting upwardly and 
perpendicularly from the center of the bottom member 50, and a pair of 
channels 54 and 56 located above the bottom member 50 on opposite sides of 
the upright center member 52. Channel 54 has a generally C-shape and has 
an opening 58 facing toward the interior of the vehicle box. The opening 
58 of channel 54 is defined by a pair of lips 60 and 62. Channel 56 has an 
opening 64. Opening 64 is defined by a pair of lips 66 and 68. Lip 66 
projects downwardly from the top of the upright center member 52 at 
approximately a 45.degree. angle. Lip 68 has a first leg 70 that projects 
upwardly from the outside edge of bottom member and a second leg 72 that 
projects upwardly and inwardly at approximately a 45.degree. angle from 
the top of the first leg 70. The opening 64 is approximately 0.025 inches 
wide and runs the entire length of the rail. 
For the apparatus to work properly, the front rail 42 should be firmly 
fixed to the top of the front wall of the vehicle box and to the front 
edge 14 of the tarp 12. Joining the tarp 12 and front rail 42 can be 
accomplished in any number of ways. For example, the front rail 42 can 
have the same general shape as the two side rails 46. As such, the front 
rail will also have a pair of channels 54 and 56. A bead, like bead 24, 
can be provided along the front edge 14 of the tarp 12. This bead can be 
inserted into channel 56 to fix the front edge 14 to the front rail 42 
(see FIG. 4). Alternatively, and as shown in FIG. 5, a loop 28 can be 
provided along the front edge 14 of the tarp 12. The loop 28 can be 
inserted into the channel 56. A flexible rod or cord 30 having a diameter 
larger than the opening 64 can be inserted into the loop 28 through the 
open end of the front rail 42 to further secure the front edge 14 of tarp 
12 and the front rail 42 together. The front edge 14 of the tarp 12 and 
the front rail 42 can also be joined together using a row of spaced snap 
closures. See FIG. 6. The snap closures can be spaced six inches apart, 
for example. Each snap closure includes a female snap member 32 fixed 
along the front edge 14 of the tarp 12 and a male snap member 34 fixed to 
the front rail 42 of the frame 40. The female snap members 32 and male 
snap members 34 are positioned and shaped to interlock to join the front 
rail 42 to the front edge 14 of the tarp 12. Each of these and other 
arrangements can be used to fix the front edge 14 of the tarp 12 to the 
front rail 42 which, as indicated above, is fixed to the top of the front 
of the truck box. 
The back rail 48 of the frame 40 has two primary functions. The first is to 
serve as a spindle about which the tarp 12 can be rolled or unrolled. The 
second is to assist in stretching the tarp 12 and holding it over the 
truck box in a covered position. To perform these functions effectively, 
the back rail 48 should not be permanently fixed to the box of the truck. 
The back rail 48, however, should be fixed to the back edge 20 of the tarp 
12. Any of the techniques described for joining the front edge 14 to the 
front rail 42 are suitable for joining the back edge 20 to the back rail 
48. To reduce production costs, the back rail 48 will preferably have the 
same elements as the two side rails 44 and 46. As such, the back rail 48 
will have a bottom member 50, and upright center wall member 52, and a 
pair of channels 54 and 56 located above the bottom member 50 and on 
opposite sides of the upright center member 52. Channel 54 will have an 
opening 58 defined by a pair of lips 60 and 62 and channel 56 will have an 
opening 64 defined by a pair of lips 66 and 68. 
An important feature of the present invention are the two cam latches 
generally designated 100 which are located at the back end of each side 
rail 46. Each cam latch has a mounting member 102. The mounting member 102 
is sized so that it can be slid into the C-shaped channel 54 through the 
back open end of the side rail. The width of the mounting member is such 
that it cannot pass through the opening 58 of the C-shaped channel 54. The 
mounting member can be fixed in place in the channel using a set screw 
104. 
Integrally molded with the mounting member 102 are a stop member 106 and a 
pair of hinge elements 108 and 110. The stop member 106 covers the back 
end of both channels 54 and 56 of the rail. The stop member 106 also 
includes a ledge 112 that projects inwardly from the side rail toward the 
other side rail. 
Each cam latch also includes a lever 114. The lever 114 is attached to the 
hinge elements 108 and 110 by a pin 116 so that the lever can rotate about 
the pin 116. The lever 114 includes a handle 118 and an engagement member 
120 at the end of the handle 118 nearest the hinge elements 108 and 110. 
The width of the engagement member is less than the width of the opening 
58 to the C-shaped channel 54 of the back rail 48. 
Now that the various components that make up the cover 10 have been 
described, its installation and operation will be explained. 
The front rail 42 and the side rails 46 are fixed to the respective tops of 
the front and side edges of the box. An attachment is made between the 
front edge 14 of the tarp 12 and the front rail 42 using any of a variety 
of techniques such as those discussed above. An attachment is also made 
between the back rail 48 and the back edge 20 of the tarp 12. The mounting 
member 102 of the two cam latches 100 are each inserted through the open 
back end of the opposing side rails 46 and secured in place using a set 
screw 104. This installation is very simple. Once complete, it allows one 
to roll the tarp 12 up around the back rail 48 toward the front rail 42 
and the front of the box or roll it out toward the back of the box. 
When one desires to cover the box, the tarp 12 is rolled out. The back rail 
48 and the tarp 12 are long enough so that the ends of the back rail 48 
can be placed between the ledge 112 and the engagement member 120 of each 
cam latch 100 with the opening 58 of the channel 54 of the back rail 48 
facing the engagement members 120. The handles 118 of the two cam latches 
100 are then rotated so that the engagement members 120 pivot toward the 
back rail 48, pass through the opening 58 into the channel 54 of the back 
rail 48 and engage the upright center member 52 of the back rail 48. 
Continued rotation of the handles force the back rail 48 back so as to 
tighten the cover and bring the back rail 48 into engagement with the 
ledges 112 of the stop members 106. Upon full rotation of the two cam 
latches 100 into the locked position (shown in FIG. 8), the ledges 112 and 
engagement members 120 cooperate to hold the tarp 12 in place. The sides 
of the tarp 12 are then fully secured in place by inserting the beads 24 
along the side edges 16 and 18 of the tarp 12 through the openings 64 of 
the channels 56 of the side rails 46 to create a sufficiently tight seal 
along each side of the tarp 12. This tight seal is created by pushing the 
head 80 of each bead all the way through the opening 64 so that base 82 of 
the head 80 of beads 22 or 24 are captured by the lips 66 and 68 of the 
opening 64 in the side rails. See FIG. 4. 
Opening the cover is also very straightforward. All one needs to do is 
rotate the handles 118 of the cam latches 100 in the opposite direction 
until the engagement members 120 are no longer positioned in the channel 
54. This serves to relieve the tension on the cover permitting the back 
rail 48 to be pushed forward past the ledge 112 and then lifted up. One 
can then roll the cover up using the back rail 48 as a spindle. The forces 
applied when rolling are generally sufficient to pull the beads 22 and 24 
from the channels 56 of the side rails 44 and 46.