US3848279A

US3848279A - Portable camping equipment

Info

Publication number: US3848279A
Application number: US00348637A
Authority: US
Inventors: W Ipsen
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-10-26
Filing date: 1973-04-06
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19
Also published as: GB1344026A

Abstract

A portable unitary covered cot foldable into a compact condition suitable for transportation by a single individual comprising a foldable rectangular frame formed by two pivotally connected Ushaped frame members. U-shaped support legs are pivotally attached to the frame at each end and in the center. U-shaped support arms to support a flexible cover attached to the frame are pivotally connected to each end of the frame. The cot is foldable from an open, horizontal position where the legs and arms extend from the frame to a closed position where the support legs are positioned against the exterior of the frame and the support arms and cover are enclosed by the folded U-shaped frame members. One important aspect of the cot structure is the provision of telescoping sides for each of the U-shaped frame members. In the retracted and folded position, the cot is quite compact and the cot structure is more readily transportable on a person''s back. In the open position, the U-shaped frames are fully extended so that the cot structure is of a length sufficient for a person to sleep therein.

Description

United States Patent 91 Ipsen, Jr.

[4 1 Nov. 19, 1974 1 PORTABLE CAMPING EQUIPMENT [76] lnventor: William lpsen, Jr., 823 S. 7th St.,

La Crosse, Wis. 54601 [22] Filed: Apr. 6, 1973 [21] Appl. No.: 348,637

Related US. Application Data [63] Continuation-impart of Ser. No. 192,025, Oct. 26,

1971, abandoned.

Primary Examiner--Casmir A. Nunberg Attorney, Agent, or Firm-Molinare, Allegretti, Newitt & Witcoff [57] ABSTRACT A portable unitary covered cot foldable into a compact condition suitable for transportation by a single individual comprising a foldable rectangular frame formed by two pivotally connected U-shaped frame members. U-shaped support legs are pivotally attached to the frame at each end and in the center. U- shaped support arms to support a flexible cover attached to the frame are pivotally connected to each end of the frame. The cot is foldable from an open, horizontal position where the legs and arms extend from the frame to a closed position where the support legs are positioned against the exterior of the frame and the support arms and cover are enclosed by the folded U-shaped frame members. One important aspect of the'cot structure is the provision of telescoping sides for each of the U-shaped frame members. In the retracted and folded position, the cot is quite compact and the cot structure is more readily transportable on a persons back. In the open position, the U-shaped frames are fully extended so that the cot structure isof a length sufficient for a person to sleep therein.

12 Claims, 7 Drawing Figures PORTABLE CAMPING EQUIPMENT- REFERENCE TO RELATED APPLICATION I This application is a continuation-in-part of my copending application Ser. No. 192,025, entitled Portable Camping Apparatus," filed Oct. 26, 1971 now abandoned.

BACKGROUND OF THE INVENTION The present invention pertains to a camping apparatus embodying a covered sleeping unit. More particular, the present invention pertains to a portable unitary camping apparatus embodying a collapsible cot and foldable canopy.

Various types of folding beds in combination with covers and canopies have been devised by the art to protect the occupants from the environment. Various prior art units may be found in the U.S. Patent Office Classification Class 135, Subclass 5.1 and Class 5, Subclasses 112, 113 and 362. Typical prior art units include U.S. Pat. Nos. 2,641,776 (Jensen); 2,508,254 (Ham); 2,367,043 (Nelson); 2,301,5 l1 (Boyce); 1,962,918 (Smith); 3,278,953 (Willis); 2,841,803 (B- dling); 3,601,825 (Moorhead et al); 3,584,322 (McDougall); 3,619,827 (MacKenzie); 3,670,750 (Johnston); and 3,158,299 (Weir et al.).

These specifically enumerated prior art apparatus, while possessive of many advantages have many incon venient disadvantages. Typical disadvantages of a given prior art apparatus in general, are the lack of true portability because of weight and bulk by a single individual', non-unitary construction requiring the transportation of components separately which can be easily misplaced; lack of means to readily assemble and disassemble the unit; unstable support legs when the unit is utilized in soft terraimand difficulty in obtaining interior ventilation when occupied.

More specifically, the Barn apparatus (U.S. Pat. No. 2,508,254) comprises a non-unitary construction. The base legs are amenable to instability in soft terrain and the various elements which make up the cot and the support for the canopy are non-unitary and require field assembly. This field assembly is time consuming and there is always the risk of losing one of the detached elements which would render assembly impossible. The Jensen apparatus (U.S. Pat. No. 2,641,776) also possesses base legs which are unstable in soft terrain. Further, the Jensen appparatus has a rigid bed and a collapsible canopy arrangement utilizing a plurality of laterally oriented support arms. This apparatus is portable only in the sense that it can be transported with the canopy collapsed on a car top. The Jensen apparatus is not portable in the sense that a single individual can readily carry the unit. Similarly, the Willis apparatus (U.S. Pat. No. 3,278,953) is portable only in the sense that it also can be collapsed for transportation on a car top but is not readily transportable by a single individ ual.

The recent patent to Moorhead et al. is primarily intended to convert an indoor cot into one useful for outdoor use and is not intended primarily as portable camping equipment which can be conveniently carried on a persons back. The McDougall patent is also primarily directed to a tent frame which is attachable to a conventional cot. The MacKenzie patent also shows a cot with a detachable tent or cover therefor. The tent portion of the MacKenzie device is quite complex and requires frame members, ropes and stakes for supporting the tent portion.

Accordingly, the art desires a true portable camping apparatus of unitary and compact construction which is readily amenable to assembly. Such an apparatus is desired by those individuals who wish to carry a covered cot on their backs on camping trips, canoe trips, extended hikes and the like which have become increasingly popular today.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a true compact, portable camping apparatus of unitary construction which is readily amenable to assembly.

It is another object of this invention to provide a portable camping apparatus which is stable in all types of terrain when occupied.

It is a further object of this invention to provide a stable, portable camping apparatus wherein the occupant can control ventilation from within.

It is a specific object of this invention to provide a unitary covered camping cot employing a frame and canopy which is collapsible from an open position to a compact closed position suitable for transportation by a single individual.

It is still a further object of this invention to provide a compact, portable camping apparatus including a tent and cot arrangement, wherein the side frames of the cot are in telescoping arrangement and are retractable to a compact condition, which is particularly suitable for back packing the equipment.

In an embodiment this invention provides a unitary covered camping cot foldable into a compact condition suitable for transportation by a single individual. This camping cot comprises a foldable rectangular frame comprising a pair of pivotally connected U-shaped frame members connected by means pivotally connecting the open end portions of each U shaped member. A pair of U-shaped end support legs are pivotally connected by the end portions of each support leg transversely to the side portions of each U-shaped frame member in close proximity to the closed end portions of each frame member. Similarly, a U-shaped intermediate support leg is pivotally connected by the end portions thereof transversely to the frame in close proximity to the open end portions of the frame members. Preferably, two intermediate support'legs are so connected, each near the end portions of each frame member. A pair of U-shaped support arms are pivotally connected by the end portions of each arm transversely to the side portions of each U-shaped frame member in close proximity to the closed end portions of each frame member. Also, provided is a means attached to the frame for defining a support surface across the rectangular frame for the horizontal support of an individual. Attached to the rectangular frame is a flexible cover having an access opening and a ventilation opening therein.

The described camping cot is foldable from a horizontal open position wherein 1) the inverted U-shaped support arms are in a generally upright position supporting the flexible cover and defining a chamber above and between the support arms and (2) the U- shaped support legs extend downward. to maintain the cot in a stable horizontal position to a closed portable compact condition. When in this closed condition, the support legs and support arms are positioned longitudinally inward parallel against the side portions of the frame. The U-shaped frame members are folded together such that the frame members are generally parallel and substantially enclose the flexible cover and the support arms and the support legs are positioned parallel against the exterior of the support members.

In a preferred form of the invention, the U-shaped frame members each include telescoping sides so that in the transporting, compact condition, the overall height of the closed equipment is significantly less than the folded condition without telescoping sides; in this way, a person carrying the equipment on his back has a compact unit to carry and more room is available, as on top of the folded cot, for carrying other camping equipment.

Other objects, embodiments and a more detailed description of the foregoing embodiment will be found in the following description of the drawings accompanying the specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the portable camping apparatus of the present invention illustrating the various elements forming the apparatus when in an open position.

FIG. 2 is an elevational view of the invention illustrating in more detail the side access opening, support legs and cover support arms.

FIG. 3 is a perspective view of the present invention in a closed, folded condition illustrating the compactness obtained when the apparatus is not in use.

FIG. 4 is a side elevational view of a preferred form of the invention wherein the sides of the U-shaped frame members, supporting both the cot and the tent portion of the equipment, are in telescoping relationship.

FIG. 5 is an enlarged, sectional, fragmentary view showing the telescoping sides of the U-shaped frame in the extended and locked condition.

FIG; 6 is a view similar to FIG. 5 showing the telescoping sides in the collapsed or retracted condition.

FIG. 7 is a side elevational view of the embodiment of FIG. 4 in the collapsed condition, particularly illustrating the compactness of the embodiment in the closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, there is illustrated a covered cot having a foldable rectangular frame having a front U-shaped member 37 and a back U-shaped member 38 having a left side portion 1 and a right side portion 2. A connecting device 3 pivotally connects the open end portions of the side members 37 and 38 and enables the rectangular frame to be foldable upwards. A U-shaped front support leg 4 comprising connecting legs 41 and horizontal transverse arm 42 is pivotally connected to the front portion of the frame by'a connecting device 5 which connects the connecting leg 41 with the left side portion 1. Support leg 4 is foldable against the exterior of side portion 1 as illustrated in FIG. 3. Similarly, a U-shaped back leg 8 is pivotally connected to the rightside portion 2 by connecting device 9. A U-shaped left center support leg 6 and a U-shaped right support center leg 7 are pivotally connected by connecting device 3 to left side member 1 and right side member 2, respectively. These port arm 10. To aid in keeping the rectangular frame in a horizontal position when unfolded, a latching device 25 is provided which connects' the horizontal closed transverse portions of legs 6 and 7. Like the front. and back U-shaped support legs, the center U- shaped support legs are foldable against the exterior side portions of the U-shaped frame member as illustrated in FIG. 3 wherein left center leg 6 is folded against left side portion 1.

A front inverted U-shaped support arm 14 comprising a closed, transverse section and a leg portion 43 is pivotally connected to the front portion of the frame by pivot device 15. To give added support to support arm 14 when in an upward position, there is provided a knee brace 16 which connects the lower portion of leg 43 with the left side portion 1. Support arms 14 and knee brace 16 are foldable inward along the lines indicated by the arrows in FIG. 2 with leg portions 43 being of sufficient length such that when the support arm 14 is folded downward against the side portion 1, the upper closed portion of the U-shaped arm does not extend past the center foldable portion of the frame. Similarly, located in the back portion of the frame is a rear inverted U-shaped support arm 11 pivotally connected to the right side portion 2 by pivot devices 13. Likewise, there is provided a knee brace 12 which connects the right side portion 2 with support 11 thereby providing additional support when support 11 is in' a generally upward position. Support arms 11 and 14 fold flat against the interior side portions of U-shaped members 37 and 38 of the frame when the unit is folded. As illustrated, supported arm 14 is preferably slightly longer than support arm 11 so as to provide additional vertical space in the front, head portion of the covered cot for an occupant.

A flexible cover 20 comprised of a suitable covering material such as canvas, having a front end panel 33, a back end panel 34, side wall 17 and top 39 is attached to the foldable frame. Located in the front panel 33 is a ventilation opening 21 which is covered by a screen 35 and an imperforate covering 36. Typically, the imperforate covering 36 is of the same general construction as cover 20 and is detachably connected to front panel 33 on the interior of the unit by means of suitable zippers or snaps. This allows an occupant to obtain ventilation within the unit in close proximity to the occupants head without requiring the occupant to leave the unit. Similarly, there is provided a side vent 23, with an appropriate screen and detachable covering as opening 21, to obtain additional circulation of air through the unit.

An access opening 24 covered by a perforate access screen 29 and an imperforate access cover 31 is located on the side of the unit. Access cover 31 is located on the exterior part of the unit and the access screen 29 on the interior with both screen 29 and cover 31 detachably connected to cover 20 by separate, doublefaced zippers 22a and 22b respectively. This doublefaced zipper arrangement allows an occupant to open either the imperforate access cover or access screen from either the interior or the exterior of the unit. In case of precipitation, there is provided a flap 18 which extends across the top of opening 24 and prevents water from entering the access opening as it runs down from the top of the unit 39. The access cover 31 is flexible and readily rolled up and, to keep the cover in a rolled up position, there is provided tie tabs 19 to tie the cover near the top of opening 24.

When support arms 11 and 14 are rotated upward from a collapsed, downward position, the arms pull cover upward and into a generally taut condition as illustrated in FIGS. 1 and 2, and define a chamber between and below the support arms for occupancy by an individual. Arms 11 and 14, however, are not directly attached to cover 20 and are independent thereof.

In FIG. 1, the flexible cover 20 may be tucked under the closed ends of the foldable frame by means of an elastic containing hem 30 by extending cover 20 under back member 37 and front member 38 when the unit is unfolded, thereby preventing the entry of insects into the unit. Snaps 44 located on right side and left side portions 1 and 2 detachably secure the cover to the frame. Located on the interior of the covered cot unit is a flexible matress 40 which provides a comfortable support for the occupant of the unit. When the unit is folded into a closed position, the hem 30 on cover 20 may be placed on either end of matress 40.

Referring to FIG. 3, there is illustrated the portable camping apparatus of the present invention in a folded, transportable condition and the parallel folded orientation of the various members. When U-shaped frame member 37 and 38 are folded upward as in FIG. 3 such that the frame members are parallel, flexible cover 20 is substantially enclosed between members 37 and 38. Also illustrated is the bottom portion of the unit and support wires 27 and springs 28 attached to the frame which provide a flexible horizontal support for matress 40 when the apparatus is in open, unfolded position. To keep the unit in a closed, folded condition, there is provided a latch device 26 which connects left side and right side portions 1 and 2 when the apparatus is folded. Latch device 26 may be provided on either or both sides of the unit. So that an individual may readily transport the covered camping cot when it is completely closed and folded, a harness 32 is detachably connected to support wires 27 so as to allow an individual to readily tote the closed compact unit on his back as one would carry a typical knapsack.

From the foregoing description and an examination of the attached drawings, it is readily seen that the prescnt invention provides a covered cot camping apparatus which is not only portable but also unitary. Preferably, the various Ushaped members of the unit are constructed from metal tubing. When so constructed, each member can be easily fabricated from a single length of tubing by bending the tubing in the appropriate places. An apparatus of the type described is readily assembled or disassembled in about I minute and is readily carried by an individual on his back for transportation to camp sites. Furthermore, the apparatus is of sufficient compactness so that when stored in car trunks, trucks, boats, etc., fortransportation, it will not occupy considerable space.

In this apparatus the entire construction is unitary and there are no additional pieces of equipment which must be packed away and assembled at the camp site. Since no additional equipment or pieces are necessary, there is no risk of losing equipment which may be required to assemble the unit.

Furthermore, there are provided U-shaped

stable legs

4, 6, 7, and 8 so that the apparatus may be readily utilized in varying conditions of terrain without any of the legs having a propensity to sink into the ground. It is also seen that there has been provided ventilation openings in the cover which are readily accessible to an occupant while occupying the unit. Hence, it is seen that the invention described and hereafter claimed provides a significant advance over those camping apparatus heretofore available in the art.

A covered camping cot, as illustrated, which in an open position is about 6 feet long, 3 feet high and 24 inches wide is foldable into a closed compact unit about 35 inches high, 24 inches wide and 8 inches deep. When fabricated out of aluminum tubing and canvas, the total weight is only about 25 pounds. Such a unit is readily carried by a single individual in a knapsack fashion keeping the individuals hands free for other tasks when toting the unit.

Referring to the preferred embodiment of FIGS. 4 7, the general structure of the embodiment is substantially the same as that of the embodiment of FIGS. 1 3. For this reason, similar structural parts will only be briefly described.

Referring to the portable apparatus 100, shown in FIG. 4, a pair of U-shaped frame members 102 are hingedly connected to a pair of intermediate connect ing members 104 at hinge connections 106. The ends of the frames 102 which are connected to the connecting members 104 are the open portions of the U-shaped frame members 102. The U-shaped frame members 102 also include a closed bottom 108 and a pair of spaced side members 110 which are interconnected by the bottom portion 108.

The connecting member 104 has hingedly connected thereto a pair of normally downwardly projecting U- shaped legs 112 which, at the open ends thereof, are hingedly connected to the connecting

members

104 and 114. The base of the legs 112 rest on the ground. A support leg 116 is hingedly connected to each of the opposite ends of each of the frame members 102 at hinge connections 118. The

U-shaped legs

112 and 116 cooperate to provide solid support for the apparatus 100 on uneven terrain because of the continuous bottom portions of the

legs

112 and 116. By using U- shaped leg members, the load is distributed over a wide -area, to thereby avoid having the legs dig into the ground and contribute to uneveness of the apparatus 100 while resting on the ground and in use.

As with the embodiment of FIGS. 1 3, the outer ends of the frame members 102 also include a pair of upright U-shaped members 120 which are hingedly connected at 122 to the opposite, outer ends of the frame members 102. A collapsible brace 124 is connected at one end to the side of the frame member 102, and at its opposite end, to a side of each upright U- shaped member 120 to thereby support each U-shaped member in the upright position. The U-shaped members 120, in the open position, are tilted, beyond the perpendicular, at least a few degrees outwardly of the ends of the camping apparatus 100, in opposite directions, in order to hold the flexible tent portion 126 relatively taught. The tent portion 126 is secured, as by snaps, to the frame members 102 and the upright U- shaped members 120 provide for positive support for the tent portion 126 in the upright position. As in the embodiment of FIGS. 1 3, suitable vent openings having screening and closures are provided for the unit Referring to FIGS. and 6, there is a detailed view of the telescoping sides 110 of the frame members 102. The side members 110 include an outer sliding tubular member 128 and an inner sliding tubular member 130. The

members

128 and 130 are preferably constructed ofa suitable metal, such as aluminum. The inner sliding member 130 includes a fixed transverse shaft 132 with a spring 134 mounted thereon. One spring end bears against the inside of the tubular member 130. The other end of the spring 134 is interconnected to a button 136 having a stop flange 138 thereon. The button 136 is positioned within an aperture 140 in the inner member 130, at all times, and in the extended position, shown in FIG. 5, the button 136 passes through an aperture 142, aligned with the aperture 140, in the outer sliding member 128 whereby the button 136 projects through both of the

apertures

140 and 142 to lock the sliding

members

128 and 130 together in the extended position. When it is desired to retract the unit, the button is depressed, and the sliding

members

128 and 130 are slidably moved to the retracted position shown in FIG. 6. The tent and cot construction 100 is foldable, in the manner illustrated in FIG. 7, and the unit is in a particularly compact condition. The overall height of top, as seen in FIG. 7, and also to make a particularly compact camping unit easily carried on a hiking or camping trip.

While in the foregoing there has been provided a detailed description of a particular embodiment of the present invention, it is to be understood that all equivalents obvious to those having skill in the art are to be included within the scope of the invention as claimed.

What I claim and desire to secure by Letters Patent ls:

l. A unitary covered camping cot foldable into a compact condition suitable for transportation by a single individual which comprises:

a. a foldable rectangular frame comprising a pair of pivotally connected lightweight U-shaped frame members, and means for pivotally connecting the open end portions of each U-shaped frame member;

b. a pair of lightweight U-shaped end support legs,

the open end portion of each being pivotally connected transversely to the side portions of each U- shaped frame member in close proximity to the closed end portions of each frame member;

0. a lightweight U-shaped intermediate support leg,

the open end portions of which being pivotally connected transversely t0 the frame in close proximity to the open end portions of the framemembers;

d. a single pair only of inverted, lightweight U-shaped support arms, the open end portions of each being permanently pivotally connected transversely to the side portions of each U-shaped frame member in close proximity to the closed end portions of each U-shaped frame member;

e. means attached to the frame for defining a support surface across the rectangular frame for the horizontal support of an individual;

f. a flexible cover attached to the rectangular frame having an access opening and ventilation opening therein, said arms being positioned between said cover and said support surface; and,

. the camping cot being foldable, from a horizontal, open position as said inverted U-shaped support arms are in a generally upright position and define flexible side support means for said flexible cover and define a chamber above and between said support arms, said single pair of U-shaped arms defines the sole support means for said cover when said cover is in the chamber defining position, and the U-shaped support legs extend downward to maintain the cot in a stable position, to a closed, portable, compact condition where the support legs and support arms are positioned longitudinally inward against the side portions of the frame and the U- shaped frame members folded together such that the frame members are generally parallel and substantially enclose both the flexible cover and the support arms and the support legs are positioned against the exterior of the frame members.

2. The camping cot of claim 1 wherein latching means are attached to the frame members to lock the frame in a closed position when folded.

3. The camping cot of claim 1 wherein a brace connects the open end portions of each support arm with the side portions of each frame member to provide support for the supports arms when in an upward position.

4. The camping cot of claim 1 including a pair of U- shaped intermediate support legs, the open end por tions of each being pivotally connected transversely to each U-shaped frame member in close proximity to the open end portions of each member.

5. The camping cot of claim 4 wherein a latching means is attached to the closed end portion of the intermediate support legs to lock the legs in a stable position when the cot is in an open position.

6. The camping cot of claim 1 wherein a harness means is detachably connected to the camping cot to provide a means for a single individual to carry the cot as a backpack when in a closed position.

7. The camping cot of claim 1 wherein the ventilation opening is covered by an outer perforate screen and an inner imperforate cover detachable from the interior.

'8. The camping cot of claim 1 wherein the access opening is covered by an imperforate cover and a perforate screen openable from the interior and exterior.

9. The camping cot of claim 8 wherein the screen and cover on the access opening are detachably connected to the imperforate cover by a double-faced zipper.

10. The camping cot of claim 8 wherein the perforate screen is interior of the imperforate cover.

11. The apparatus of claim 1 wherein said U-shaped frame members include telescoping side portions movable from a retracted position when said cot is in its closed portable compact condition and to an extendable position when the cot is in its horizontal, open position.

12. The apparatus of claim 1 wherein said U-shaped support arms, in the upright position are tilted outwardly in opposite directions away from each other being said support arms in said position, said means being yond a perpendicular position relative to said frame interconnected both to said frame members and to said members for holding the flexible cover in a substansupport arms. tially taut condition, and means are provided for hold-

Claims

1. A unitary covered camping cot foldable into a compact condition suitable for transportation by a single individual which comprises: a. a foldable rectangular frame comprising a pair of pivotally connected lightweight U-shaped frame members, and means for pivotally connecting the open end portions of each U-shaped frame member; b. a pair of lightweight U-shaped end support legs, the open end portion of each being pivotally connected transversely to the side portions of each U-shaped frame member in close proximity to the closed end portions of each frame member; c. a lightweight U-shaped intermediate support leg, the open end portions of which being pivotally connected transversely to the frame in close proximity to the open end portions of the frame members; d. a single pair only of inverted, lightweight U-shaped support arms, the open end portions of each being permanently pivotally connected transversely to the side portions of each U-shaped frame member in close proximity to the closed end portions of each U-shaped frame member; e. means attached to the frame for defining a support surface across the rectangular frame for the horizontal support of an individual; f. a flexible cover attached to the rectangular frame having an access opening and ventilation opening therein, said arms being positioned between said cover and said support surface; and, g. the camping cot being foldable, from a horizontal, open position as said inverted U-shaped support arms are in a generally upright position and define flexible side support means for said flexible cover and define a chamber above and between said support arms, said single pair of U-shaped arms defines the sole support means for said cover when said cover is in the chamber defining position, and the U-shaped support legs extend downward to maintain the cot in a stable position, to a closed, portable, compact condition where the support legs and support arms are positioned longitudinally inward against the side portions of the frame and the U-shaped frame members folded together such that the frame members are generally parallel and substantially enclose both the flexible cover and the support arms and the support legs are positioned against the exterior of the frame members.

4. The camping cot of claim 1 including a pair of U-shaped intermediate support legs, the open end portions of each being pivotally connected transversely to each U-shaped frame member in close proximity to the open end portions of each member.

8. The camping cot of claim 1 wherein the access opening is covered by an imperforate cover and a perforate screen openable from the interior and exterior.

12. The apparatus of claim 1 wherein said U-shaped support arms, in the upright position are tilted outwardly in opposite directions away from each other beyond a perpendicular position relative to said frame members for holding the flexible cover in a substantially taut condition, and means are provided for holding said support arms in said position, said means being interconnected both to said frame members and to said support arms.