Truck box extension apparatus

An extension apparatus (10) for vehicles is disclosed. The extension apparatus (10) includes a frame assembly having upper and lower frame members (12a,b) which are interconnected by a flexible member (16) attached at the lower and upper edges thereof to the lower and upper frame members (12a,b). The frame assembly is adjustable between raised and lowered positions. The extension apparatus further includes jack means (18) pivotable about a horizontal axis parallel to flexible member (16) and releasably attached to the lower and upper frame members (12a,b), on a cargo bed side of the flexible member, for raising said upper frame member (12b) into the raised position. The frame assembly is suitably attached to the top of the sidewalls (20) of the cargo bed area.

TECHNICAL FIELD OF THE INVENTION 
Present invention relates to an extension apparatus for a truck box or the 
like. More particularly, the present invention relates to an adjustable 
extension which attaches to the top of the sidewalls of an open cargo bed 
area or the like, the adjustable extension being raised or lowered for 
volume control and/or height restrictions as required without the 
necessity of removal from the truck body. 
BACKGROUND OF THE INVENTION 
Extension apparatus for trucks or the like which increase the volume and 
height of the cargo or bed portion of such a vehicle are known in the art. 
However, most extension apparatus require removal from the body of the 
vehicle when not in use and reattachment thereto when in use. This 
requires much time and effort and often necessitates the presence of 
special tools. In addition, the extension apparatus often will not be 
readily available when needed. 
To overcome these and many other problems associated with removable 
extension apparatus, extension apparatus have been designed which remain 
permanently attached to the body of the truck thereby doing away with the 
necessity to remove the apparatus when not in use. 
An example of such an extension apparatus can be found in U.S. Pat. No. 
4,095,838 issued to Arnold Beeler on June 20, 1978. However, the Beeler 
patent has several problems associated therewith. For example, flexible 
fabric is attached between two channel members which in turn are supported 
in an extended upright, spaced apart relationship by a plurality of 
horizontally spaced jack-knife support members. The jack-knife support 
members have a tendency to bind and twist unless the entire extension 
apparatus is raised substantially simultaneously. Additionally, the 
jack-knife members are positioned on the outside of the flexible fabric 
material such that the cargo of the truck box will push the fabric into 
the jack-knife members thereby causing wear of the fabric. 
Furthermore, the positioning of the jack-knife members on the outside of 
the flexible fabric will often create problems in reaching the extension 
apparatus during the raising and lowering process. Indeed, it does not 
appear as though the jack-knife members can be positioned on the inside of 
the flexible fabric as they will interfere with the fabric material during 
the folding process when the extension apparatus is lowered. 
Additionally, the rectangular open channel-like construction of the paper 
and lower frame members to which the jack-knife members are attached makes 
the frame-like members very susceptible to collecting debris such as 
grain, ice, etc. which might obstruct raising and lowering of the fabric 
extension. 
Furthermore, and very importantly, the Beeler extension apparatus does not 
appear to have the required strength and sturdiness characteristics needed 
to support such items as roll-up tarp apparatus which are used to enclose 
the cargo area. 
The present invention solves these and many other problems associated with 
the prior art. 
SUMMARY OF THE INVENTION 
The present invention relates to an extension apparatus for vehicles. The 
extension apparatus includes a frame assembly having upper and lower frame 
members. The frame assembly is adjustable between raised and lowered 
positions. A flexible member is attached at the upper and lower edges 
thereof to the upper and lower frame members. The extension apparatus 
further includes means releasably attached to the upper and lower members 
for raising the upper frame member into the raised position. 
A particularly advantageous feature of the present invention is that the 
present invention need not be removed from the top of the cargo area 
sidewalls when not in use. This provides for an extension apparatus which 
is readily raised or extended so as to increase the volume and height of 
the cargo area as needed. Additionally, few special tools are required to 
raise or lower the extension apparatus. Furthermore, the structural 
features and design of the present invention make it easily extended into 
its operational raised position or folded down into its lowered storage 
position on the top of the cargo area sidewalls. 
In one embodiment of the present invention, jack apparatus spaced apart 
from one another are utilized to raise the upper frame member above the 
lower frame member into the raised position. The jack apparatus are 
adjustable to enable raising the upper frame member varying distances from 
the lower frame member. This increases the ease with which the frame 
assembly can be raised into its upright position as one end of the frame 
assembly can be partially extended and then the other end extended such 
that the entire frame assembly need not be raised simultaneously. The jack 
apparatus thus assures uniform vertical tension throughout the flexible 
member. 
Yet another advantageous feature of another embodiment of the present 
invention, is the positioning of the jack apparatus on the inside of the 
flexible member such that the cargo in the cargo area pushes out on the 
flexible member. Consequently, the flexible member does not rub against 
the jack apparatus thereby reducing wear. 
Furthermore, the present invention is constructed and arranged such that 
debris does not interfere with the raising and lowering of the present 
invention. 
A most significant feature of the present invention is the ability of the 
flexible member in one embodiment to slide longitudinally of the frame 
members thereby enabling both uniform vertical tension and uniform 
horizontal tension which results in increased sturdiness. In addition to 
the uniform tension, the jack apparatus are positioned relatively close to 
the flexible member when in the extended position thus increasing further 
the over-all sturdiness of the extension apparatus of the present 
invention such that it will resist buffeting by the wind and can be 
utilized with roll-up tarp apparatus. 
Furthermore, the present invention can be made of a light-weight material 
thereby increasing the vehicle's efficiency over conventional extension 
apparatus. 
These and various other apparatus and features of novelty which 
characterize the present invention are pointed out with particularity in 
the claims annexed hereto and forming a part hereof. However, for a better 
understanding of the invention, its advantages, and objects obtained by 
its use, reference should be had to the drawings which form a further part 
hereof, and to the accompanying descriptive matter, in which there is 
illustrated and described a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION 
Referring now to the drawings there is shown in FIG. 1 a preferred 
embodiment of an extension apparatus embodying the principles of the 
present invention, generally referred to by reference numeral 10, which is 
mounted on top of sidewalls 20 of a truck box or cargo bed area. It will 
be appreciated, that while the following detailed description discusses 
the application of the present invention to the cargo box of a truck, the 
present invention will have utility in varying applications. 
The present invention is adjustable between raised (see FIG. 1) and lowered 
(see FIG. 2) positions. As illustrated in FIG. 1, the present invention 
includes lower and upper frame members 12a, 12b interconnected by a 
flexible planar member 16 which, in some applications, might be a flexible 
fabric-like material. Horizontally spaced apart jack apparatus 18 
releasably interconnected to the lower and upper frame members 12a, 12b 
are utilized to raise the extension apparatus into an extended or raised 
position. Once in the raised position, the jack apparatus 18 assists in 
retaining the extension apparatus 10 in the raised position. In FIG. 2, 
the present invention is shown in the lowered position with the jack 
apparatus 18 removed therefrom. 
More particularly, as illustrated in FIG. 4, the lower and upper frame 
members 12a, 12b include hollow generally five-sided polygonal-shaped 
structures having roughly parallel vertical sides 22a,b and 24a,b, 
respectively and horizontal bottom and top surfaces 26a,b, respectively. 
The opposing or facing surfaces of each of the members 12a, 12b have first 
and second portions 28a,b and 29a,b, respectively. Surfaces 28a,b are 
generally horizontal such that when the present invention is in the 
lowered position as illustrated in FIG. 4, surface 28b rests on surface 
28a. The surfaces 29a,b interconnect surfaces 28a,b and 24a,b and are 
oblique with respect to the surfaces 28a,b and 24a,b, thereby defining a 
wedge or gap between frame members 12a,b adjacent the surfaces 29a,b when 
the present invention is in the lowered position. 
The oblique surfaces 29a,b define arcuately-shaped channels 30a, b 
extending longitudinally of frame members 12a,b. The channels 30a,b define 
a cavity having a somewhat restricted opening to the surfaces 29a,b. The 
restricted openings are generally vertically directed and aligned 
vertically opposite each other. The frame members 12a,b are beveled and 
interconnected at the corners of the extension apparatus 10 so as to 
define continuous channels extending longitudinally about the frame 
members 12a,b. 
As illustrated in FIGS. 3 and 4, the flexible member 16 has a hem-like 
portion 32a,b extending along the lower and upper edges thereof. Each of 
the hems 32a,b, has a flexible, arcuately-shaped member such as a rope 
34a,b, respectively which is sewn or suitably attached therein such that 
the hem 32a,b, is adapted for slidable mounting in the channel portions 
30a,b, which are constructed and arranged such that the restriction 
portion thereof retains the hem portions 32a,b in the channel portions 
30a,b. The hem portions 32a,b might be formed by sewing the edges of the 
flexible member 16 or by any other suitable method. The flexible member 
16, due to its slidable mounting in the channel portions 30a,b, is 
horizontally stretched or tightened so as to have uniform horizontal 
tension throughout. Furthermore, when the frame assembly is extended into 
the raised position, the flexible member 16 is positioned in a generally 
vertical plane and has generally uniform vertical tension throughout. 
As illustrated in FIG. 3, the lower frame member 12a is suitably fastened 
to the top of the sidewalls 20 so as to retain the extension apparatus 10 
on the sidewalls 20. In the embodiment shown, a bolt-like member 36, 
having a head portion 38, is inserted through vertically aligned apertures 
in the surfaces 28a and 26a of the frame member 12a and threaded into the 
top of the sidewall 20 or suitably attached thereto. The aperture in the 
surface 26a is constructed and arranged such that the head portion 38 of 
the bolt-like member 36 is mounted in the frame member 12a so as to be 
flush with the surface 28a thereof. Consequently, the bolt-like member 36 
does not prevent the upper member 12b from resting on the lower frame 
member 12a in the lowered position. As illustrated in FIG. 4, the flexible 
member 16 typically folds and hangs on the inside of the cargo bed area 
when the extension apparatus 10 is in the lowered position. The flexible 
member 16 extends from the channel portions 30a,b through the gap between 
the surfaces 29a,b and into the cargo bed area. 
As illustrated in FIGS. 1 and 3, when in the raised position, the flexible 
member 16 of the extension apparatus 10 is stretched tightly between the 
lower and upper frame members 12a,b so as to have relatively uniform 
vertical tension throughout. As illustrated in FIG. 6 the extension 
apparatus, due to the relatively uniform horizontal and vertical tightness 
of the flexible member 16, is sturdy and capable of supporting a roll-up 
tarp apparatus 80 which might be utilized to cover the cargo bed area. 
While there are various roll-up tarp apparatus available on the market, the 
roll-up tarp apparatus illustrated in FIG. 6 includes a tarp 82 rolled 
onto a tube 88 along one edge thereof. The tarp 82 and the tube 88 are 
supported by spaced apart truss member 84' or beam members 84 which are in 
turn suitably secured to the upper frame member 12b. The beam members 84 
span from the upper frame member 12b on one side of the cargo bed to the 
upper frame member 12b on the other side of the cargo bed thereby 
providing a frame work over which the tarp can be positioned. The tarp 82 
is illustrated in FIG. 7 as being fastened to the upper frame member 12b 
along one side of the cargo bed by a clamp apparatus 86 which includes an 
arcuate portion for retaining a hem portion of the tarp which has an 
elongated member 89 inserted therein and a portion projecting above the 
surface of the tarp 82 so as to retain the roll of tarp on top of the 
cargo bed when the tarp is in the stored, rolled-up position. To use the 
tarp, the tarp 82 is rolled across the beam members 84 by attaching a 
crank handle to a universal joint at the back end of the tube 88 and 
consequently rotating the handle. The tarp 82 is then held in the end 
closed position by hold down straps suitably fastened to the side of the 
cargo bed by hold down clamp apparatus 90. It will be appreciated that the 
present invention might be utilized with other variations of roll-up tarp 
apparatus and that the particular configuration shown is merely exemplary 
of the present inventions utility with roll-up tarp apparatus. 
In addition, the present invention will resist any wind resistance imparted 
thereon by the moving vehicle. Furthermore, the present invention is 
sufficiently sturdy to oppose any forces exerted thereon by typical cargo 
loads. 
The extension apparatus 10 of the present invention is raised into the 
raised position by the horizontally spaced apart jack-like extender 
apparatus 18 illustrated in FIGS. 3 and 5. The jack apparatus 18 includes 
two elongated members 50 and 52 operatively connected to each other. In 
one embodiment, one inch square tubing is utilized to form members 50 and 
52. The member 52 includes a first relatively straight portion 52a and a 
second relatively straight portion 52b which is oblique with respect to 
the first portion 52a. The member 50 is slidably attached to the member 52 
by a generally U-shaped bracket 54. The bracket 54 includes a set screw 56 
or the like for releasably attaching the bracket 54 to the straight 
portion 52a of the elongated member 52 such that the bracket 54 is mounted 
for adjustable movement along the straight portion 52a of the member 52. 
The top end of the elongated member 52 includes an extension 66 adapted for 
releasable reception in an aperture 68b defined by the surface 29b 
adjacent the channel portion 30b. The elongated member 50 includes an 
extension 70 at the lower end thereof adapted for releasable reception in 
an aperture 68a defined by the surface 29a adjacent channel portion 30a. 
The member 50 is pivotally attached opposite the upper end thereof to the 
bracket 54 by a pivot shaft 58 and bushing 60 combination thereby enabling 
member 50 to be pivoted away and toward leverage handle portion 52a. 
Furthermore, member 50 is interconnected at a location between its upper 
and lower ends to the member 52 along straight portion 52a by a pair of 
elongated members 62 which define apertures 64 therein. In the preferred 
embodiment shown, each of the interconnecting members 62 defines two 
spaced apart apertures 64 which are aligned with those on the other member 
62. 
Consequently, to raise the extension apparatus 10 of the present invention, 
it will be appreciated that the upper frame member 12b is manually raised 
by hand to a height above the lower frame member 12a such that the 
extensions 70 and 66 of the jack apparatus 18 can be inserted into the 
apertures 68a,b, respectfully, of the frame members 12a,b. The handle 
portion 52a of the jack apparatus 18 is then forced downwardly toward the 
elongated member 50 and the flexible member 16 so as to function as a 
leverage arm thereby causing the elongated members 50, 52 to pivot about 
the pivot shaft 58 which results in the ends of the jack apparatus, 
including extension 66 and 70, moving farther apart and raising extension 
apparatus 10. As the jack apparatus pivots, it moves in closer to the 
flexible member 16. As illustrated in FIG. 5, the jack apparatus 18 may be 
locked by a lock pin 72 in a partially extended position or locked in a 
fully extended position as illustrated in FIG. 3. 
The adjustable bracket 54 enables variable adjustment in the amount of 
spacing between the lower and upper frame members 12a,b when in the raised 
position which correspondingly varies the tightness of the flexible 
members 16. 
When in the stored lowered position, the upper frame member 12b is suitably 
attached to the lower frame member 12a so as to be retained on the truck 
walls. As illustrated in FIG. 4, the upper frame member 12b might be 
attached to the lower frame member 12a by spaced apart bolt-like members 
74 or the like. It will be appreciated that other methods of attaching the 
upper frame member to the lower frame member might be utilized. 
The present invention is assembled by welding or fastening by other 
suitable methods, the lower and upper frame members 12a,b, together at 
their corners to form the rectangular configuration required to fit on top 
of the cargo area sidewalls 20. The flexible member 16 is then inserted 
into the continuous channel portions 30a,b. This can be accomplished by 
varying methods. In one method, one of the corners is left unattached 
until the flexible member 16 is inserted into the channel portions 30a,b. 
In another method, an access groove or channel is formed transversly in 
the frame members 12a,b so as to provide access to the channnel portions 
30a,b thereby enabling the flexible member 16 to be inserted into the 
channel portions 30a,b after the frame work has been assembled. 
After the flexible member 16 is positioned in the channel 30a,b, it is 
pulled tight so as to have uniform force on the tension throughout. This 
is made possible by the slidable mounting of the flexible member 16 in the 
channels 30a,b of the frame members 12a,b. After being suitably tightened, 
the loose ends of the flexible member 16 are suitably fastened to one 
another. This might be accomplished by gluing the ends of the flexible 
member, by a welding process, etc. 
After having assembled the extension apparatus 10, it is next fastened to 
the top of the sidewalls 20 of the cargo bed area by spaced apart 
bolt-like members 36 as illustrated in FIG. 3 or any other suitable 
methods in keeping with the principles of the present invention. 
To raise the extension apparatus 10 into the raised position, one of the 
jack apparatus 18 might be positioned in the apertures 68a,b near one end 
of the frame members 12a,b. The jack apparatus 18 is then placed in a 
partially extended position as illustrated in FIG. 5 and the lock pin 72 
attached to retain the jack apparatus 18 in the partially extended 
position. The other end of the frame members 12a,b is then similarly 
raised by the use of one of the jack apparatus 18. The frame members 12a,b 
can then be fully extended into the raised position by a similar process 
and the jack apparatus 18 locked into position by the lock pin 72. Thus, 
the present invention provides for the raising or extending of the 
extension apparatus 10 without necessitating the simultaneous extension or 
raising of the entire frame assembly. This provides for easier operation 
and more uniform verticle tension in the flexible member 16. 
It is to be understood, however, than even though these numerous 
characteristics and advantages of the invention have been set forth in the 
foregoing description, together with details of the structure and function 
of the invention, the disclosure is illustrative only, and changes may be 
made in detail, especially in matters of shape, size and arrangement of 
parts within the principle of the invention, to the full extent indicated 
by the broad general meaning of the term in which the appended claims are 
expressed.