Title:
Collapsible shelter having a reinforced truss and telescoping leg
Kind Code:
A1


Abstract:
A collapsible shelter has a canopy supported by legs and a center post. The legs and center post are rigidly fixed in position by eave and truss assemblies made from scissor type linkages. The ends of the scissor type linkages can be coupled to create a robust frame assembly. A locking button fixes the scissor linkages to the center post and a strap couples secures the interconnections between scissor linkages. The legs telescope in a non-binding manner and include curved footings for easy assembly and disassembly.



Inventors:
Goldwitz, Brian L. (Orange, CT, US)
Application Number:
10/978648
Publication Date:
09/22/2005
Filing Date:
11/01/2004
Primary Class:
International Classes:
E04H15/28; E04H15/38; E04H15/50; (IPC1-7): E04H15/28; E04H15/38; E04H15/50
View Patent Images:
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Primary Examiner:
YIP, WINNIE S
Attorney, Agent or Firm:
LOCKE LORD LLP (BOSTON, MA, US)
Claims:
1. A truss assembly for a collapsible shelter frame, comprising: a scissor unit having first and second cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end, the first ends being coupled to a center post and the second ends being coupled to an eave assembly; and means for selectively fixing an end of the first cross piece with respect to an end of the second cross piece.

2. A truss assembly as recited in claim 1, further comprising a coupling assembly that is slidingly mounted to the center post, wherein the coupling of the first end of the first cross piece is accomplished by pivotally attaching the first end of the first cross piece to the coupling assembly and the means is a spring-biased button on the center post to selectively fix the coupling assembly thereto.

3. A truss assembly as recited in claim 2, wherein the first end of the second cross piece is pivotally coupled to the center post.

4. A truss assembly as recited in claim 1, wherein the means is a connector having a strap and a buckle, the connector selectively coupling the second ends of the cross pieces.

5. A truss assembly as recited in claim 4, wherein the connector further comprises a portion for connecting to a canopy.

6. A truss assembly as recited in claim 1, wherein the second cross piece is substantially horizontal.

7. A portion of a collapsible frame for a shelter, comprising: a first scissor unit having first and second cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end; a second scissor unit having third and fourth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end, wherein the first ends of the first and third cross pieces are pivotally connected, and the first ends of the second and fourth cross pieces are pivotally connected; and a connector selectively couples the first ends of the first and second cross pieces together.

8. A portion as recited in claim 7, further comprising: a first leg, wherein the second ends of the first and second cross pieces are pivotally coupled thereto; and a second leg, wherein the second ends of the third and fourth cross pieces are pivotally coupled thereto.

9. A portion as recited in claim 7, wherein the connector is a strap and buckle.

10. A portion as recited in claim 7, wherein the connector includes a strap and a buckle capable of engaging a hole formed in a canopy for the collapsible shelter frame.

11. A portion as recited in claim 7, further comprising a third scissor unit having fifth and sixth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end, wherein the first ends of the fifth and sixth cross pieces are pivotally coupled to the first, second, third, and fourth cross pieces such that the connector couples the first ends of the fifth and sixth cross pieces together.

12. A portion as recited in claim 11, wherein the second end of the fifth cross piece is adapted to slidingly engage a center post, and the second end of the sixth cross piece is pivotally coupled to the center post; and further comprising a spring-biased button to selectively fix the second end of the fifth cross piece to the center post.

13. A center apex assembly for a collapsible shelter, comprising: a center post having an upper end and a lower end; a coupling assembly slidingly mounted on the center post intermediate the upper end and the lower end, the coupling assembly having a plurality of mounts for connecting structural members thereto; and a means for selectively locking the coupling assembly at a position intermediate the upper and lower ends.

14. A center apex assembly as recited in claim 13, wherein the center post telescopes and the upper end of the center post is dome-shaped.

15. A center apex assembly as recited in claim 13, wherein the plurality of mounts are formed to receive a substantially horizontal member to improve headroom.

16. A center apex assembly as recited in claim 13, wherein the means is a spring-biased button that can be depressed to allow the coupling assembly to pass over the button.

17. A truss assembly for a collapsible shelter frame, comprising: a roof assembly; and at least three leg assemblies for supporting the roof assembly above a surface, each leg assembly having a foot for resting on the surface, wherein the foot has a curved outer rim.

18. A truss assembly as recited in claim 17, wherein each leg assembly is multi-sided in cross-section and each leg assembly includes at least three telescoping portions, wherein at least two portions have locking means, each locking means being on a different side of the leg assembly.

19. A truss assembly as recited in claim 18, wherein the locking means is a spring-biased button that can be depressed to allow the at least three telescoping portions to pass within each other.

20. A truss assembly as recited in claim 19, wherein at least one of the spring-biased buttons has a flat end that allows coupling to a hole formed in the respective portion even when the respective portion is telescoped inside another portion.

21. A truss assembly as recited in claim 17, wherein each leg includes at least three telescoping portions and forms a plurality of holes that are offset and further comprising at least two spring-biased buttons on each leg assembly for engaging the plurality of holes to selectively set a length of the leg assembly.

22. A collapsible shelter comprising: a center post having an upper and a lower end; an eave assembly having a first scissor unit having first and second cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end; a second scissor unit having third and fourth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end, wherein the first ends of the first and third cross pieces are pivotally connected, and the first ends of the second and fourth cross pieces are pivotally connected; a connector selectively coupling the first ends of the first and second cross pieces together; at least two leg assemblies, each leg assembly having a foot for resting on the surface, wherein the second ends of the first and second cross pieces are pivotally coupled to a first leg, and wherein the second ends of the third and fourth cross pieces are pivotally coupled to a second leg; a third scissor unit having fifth and sixth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end, the first ends being coupled to the center post and the second ends being coupled to an eave assembly such that the connector selectively couples the second ends of the fifth and sixth cross pieces together; and means for selectively fixing the first end of the fifth cross piece with respect to the first end of the sixth cross piece.

23. A collapsible shelter as recited in claim 22, further comprising a connector assembly that is slidingly mounted to the center post intermediate the upper and lower ends, the connector assembly having a plurality of mounts for connecting structural members thereto, and wherein the coupling of the first end of the fifth cross piece is accomplished by pivotally connecting the cross piece to the mount of the connector assembly.

24. The collapsible shelter as recited in claim 23, wherein the first end of the sixth cross piece is pivotally coupled to the center post.

25. The collapsible shelter as recited in claim 23, wherein the means is a spring-biased button on the center post that can selectively fix the connector thereto or be depressed to allow the coupling assembly to pass over the button.

26. A collapsible shelter as recited in claim 22, wherein the connector is a strap and a buckle.

27. A collapsible shelter as recited in claim 22, wherein the connector further comprises a portion for connecting to a canopy.

28. A collapsible shelter as recited in claim 22, wherein the sixth cross piece is substantially horizontal.

29. A collapsible shelter as recited in claim 22, wherein the center post telescopes.

30. A collapsible shelter as recited in claim 22, wherein the upper end of the center post is dome-shaped.

31. A collapsible shelter as recited in claim 22, wherein each leg assembly is multi-sided in cross-section and each leg assembly includes at least three telescoping portions, wherein at least two portions have locking means, each locking means being on a different side of the leg assembly.

32. A collapsible shelter as recited in claim 31, wherein the locking means is a spring-biased button that can be depressed to allow the at least three telescoping portions to pass within each other.

33. A collapsible shelter as recited in claim 32, wherein at least one of the spring-biased buttons has a flat end that allows coupling to a hole formed in the respective portion even when the respective portion is telescoped inside another portion.

34. A collapsible shelter as recited in claim 22, wherein each leg includes at least three telescoping portions and forms a plurality of holes that are offset and further comprising at least two spring-biased buttons on each leg assembly for engaging the plurality of holes to selectively set a length of the leg assembly.

35. A collapsible shelter as recited in claim 34, wherein each spring-biased button may engage more than one of the plurality of holes.

36. A collapsible shelter as recited in claim 34, wherein a middle portion of the at least three telescoping portions is longer than a top portion of the at least three telescoping portions.

37. A collapsible shelter as recited in claim 22, wherein a foot of a leg assembly has a curved outer rim.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 200420020981.8, filed Mar. 17, 2004, Chinese Patent Application No. 200420020986.0, filed Mar. 17, 2004, Chinese Patent Application No. 200420021066.0, filed Mar. 19, 2004, and Chinese Patent Application No. 200420021142.8, filed Mar. 22, 2004, each of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject disclosure relates generally to shelters, and more particularly to an improved shelter having a collapsible frame. Even more particularly, the subject disclosure relates to a shelter including a canopy supported by a cable mounted on a collapsible frame.

2. Background of the Related Art

Over the years, many tents and other shelters having collapsible frames have been introduced. Such structures are commonly used to provide shelter during camping trips, picnics, parties, military operations, and other outdoor activities. One advantageous feature of such structures is their ability to fold into more compact configurations for storage and transport because of their collapsible frames.

However, several problems associated with collapsible shelters have been observed. The frames tend to be difficult to fold and unfold, unstable, somewhat large when folded, and prone to breakage. Some prior shelter frames also allow the overlying canopy to sag in an unsightly manner. In view of these apparent shortcomings, many attempts at overcoming these difficulties have been patented, such as: U.S. Pat. Nos. 4,779,635; 5,511,572; 5,632,293; 5,638,853; 5,701,923; 5,797,412; 5,813,425; and 6,173,726 (each of which is incorporated herein by reference in their entirety).

For example, U.S. Pat. No. 4,779,635 ('635 patent) discloses a collapsible canopy structure 10 with scissor assemblies 60 interconnecting four vertical corner poles 22. While the scissor-type linkages provide an easily folded frame, users often suspend items from the linkages or even rest hands thereon resulting in distortion and/or breakage of the structure. Once distorted or broken, the structure 10 becomes unusable. For another example, U.S. Pat. No. 6,173,726 ('726 patent) discloses an eave assembly for a collapsible shelter. The eave assembly of the '726 patent includes pairs of bars 10-1, 10-2 coupled to another pair of bars 20-1, 20-2 by a center bracket 30. Support bars 100 help support the eave assemblies in place with respect to the corner legs 150. The structure taught by the '726 patent is relatively strong compared to that of the '635 patent. However, the '726 structure does not possess the ease of folding seen with the scissor-type linkages. In view of the above, it would be desirable to have a collapsible shelter that possesses the advantage of scissor-type linkages while overcoming the disadvantages.

The structure 10 of the '635 patent includes a center post assembly 52 in order to maintain the canopy covering 12 in a taut condition. The center post assembly 52 has a dome shaped top 59 that is spring-biased against the canopy covering 12. Although the spring-biasing of the post 58 keeps the canopy 12 taut, the center post assembly 52 provides no additional structural support to the structure 10. It is desirable that a center post serves both to maintain the canopy cover taut and also to enhance the structural frame.

The canopy structure 10 of the '635 patent also includes telescoping corner poles 22. The corner poles 22 have a lower member 26 that telescopes within an upper member 24. A button latch 27 selectively fixes the corner poles 22 in either the fully extended or telescoped positions. Such a two-piece corner pole 22 limits both the maximum fully extended height as well as the minimum telescoped down length. Further, the corner poles 22 include a foot 30. A typical prior art footing is shown in FIG. 8. The footing of FIG. 8 is a flat, rectangular piece of metal attached to the bottom of the corner pole. Such prior art footings prevent easy folding and unfolding of the structure 10 because of edges that catch upon or even dig into the support surface during folding. There is a need, therefore, for a collapsible shelter with legs that are superior to those known in the prior art. In particular, a shelter frame leg with a plurality of telescoping portions that is easily folded and unfolded, yet still effective in supporting a canopy assembly at a plurality of heights is desired.

SUMMARY OF THE INVENTION

The present invention is directed to a collapsible shelter. The collapsible shelter includes an eave assembly having first and second scissor units. The first scissor unit has first and second cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end. The second scissor unit has third and fourth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end. The first ends of the first and third cross pieces are pivotally connected, and the first ends of the second and fourth cross pieces are pivotally connected. A connector selectively couples the first ends of the first and second cross pieces together.

The collapsible shelter also includes a center post having an upper and a lower end. A third scissor unit has fifth and sixth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end. The first ends of the fifth and sixth cross pieces are coupled to the center post. The second ends are coupled to an eave assembly such that the connector selectively couples the second ends of the fifth and sixth cross pieces together. The shelter also includes means for selectively fixing the first end of the fifth cross piece with respect to the first end of the sixth cross piece.

The collapsible shelter as described above possesses several advantages. By selectively coupling the cross pieces of the various scissor units, the structure can be strengthened while still allowing for easy folding into a compact configuration. Such a structure therefore incorporates the advantage of scissor-type linkages while overcoming the disadvantages. Further, the coupling of the scissor unit to both the center post and the eave assembly allows the a center post to both maintain the canopy cover taut and also enhance the structural frame.

The collapsible shelter incorporates at least two leg assemblies, each leg assembly having a foot for resting on the surface. The second ends of the first and second cross pieces are pivotally coupled to a first leg. The second ends of the third and fourth cross pieces are pivotally coupled to a second leg. In one embodiment, each leg assembly includes at least three telescoping portions and forms a plurality of holes that are offset. At least two portions have locking means, each locking means being on a different side of the leg assembly. Each leg assembly incorporates at least two spring-biased buttons for engaging the plurality of holes to selectively set a length of the leg assembly. Such a leg assembly is easily folded and unfolded, yet still effective in supporting a collapsible shelter at a plurality of heights.

Another aspect of the invention is a truss assembly for a collapsible shelter frame, comprising a scissor unit having first and second cross pieces that are pivotally connected substantially about respective midpoints. Each cross piece has a first and a second end, the first ends being coupled to a center post and the second ends being coupled to an eave assembly. The truss assembly also includes a means for selectively fixing an end of the first cross piece with respect to an end of the second cross piece. In one embodiment, the truss assembly further comprises a coupling assembly that is slidingly mounted to the center post, to which the first end of the first cross piece pivotally attaches. In another embodiment, the connector further comprises a portion for connecting to a canopy.

Another aspect of the invention is a portion of a collapsible frame for a shelter. The portion includes a first scissor unit having first and second cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end. The portion further includes a second scissor unit having third and fourth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end. The first ends of the first and third cross pieces are pivotally connected, and the first ends of the second and fourth cross pieces are pivotally connected. A connector selectively couples the first ends of the first and second cross pieces together. In one embodiment, the portion further comprises first and second legs. The second ends of the first and second cross pieces are pivotally coupled to the first leg, while the second ends of the third and fourth cross pieces are pivotally coupled to the second leg. In another embodiment, the portion further comprises a third scissor unit. The third scissor unit has fifth and sixth cross pieces that are pivotally connected substantially about respective midpoints, each cross piece having a first and a second end. The first ends of the fifth and sixth cross pieces are pivotally coupled to the first, second, third, and fourth cross pieces such that the connector couples the first ends of the fifth and sixth cross pieces together.

Yet another aspect of the invention is a center apex assembly for a collapsible shelter. The apex assembly includes a center post having an upper end and a lower end. A coupling assembly is slidingly mounted on the center post intermediate the upper and lower ends and has a plurality of mounts for connecting structural members. The apex assembly includes means for selectively locking the coupling assembly at a position intermediate the upper and lower ends. In one embodiment, the center post of the apex assembly telescopes.

It should be appreciated that the present invention can be implemented and utilized in numerous ways, including without limitation as a process, an apparatus, a system, a device, and a method for applications now known and later developed. These and other unique features of the system disclosed herein will become more readily apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those having ordinary skill in the art to which the disclosed system appertains will more readily understand how to make and use the same, reference may be had to the following drawings.

FIG. 1 is a perspective view of an assembled collapsible shelter constructed in accordance with a preferred embodiment of the subject disclosure.

FIG. 2 is a perspective view of the frame assembly of the shelter of FIG. 1.

FIG. 3 is a localized view of the scissor-type linkage of the frame assembly of FIG. 2.

FIG. 4 is a localized view of the center coupling of the frame assembly of FIG. 2.

FIG. 5A is a cross-sectional view of the center coupling assembly of the frame assembly of FIG. 2 in the disassembled position.

FIG. 5B is a cross-sectional view of the center coupling assembly of the frame assembly of FIG. 2 in the assembled position.

FIG. 6A is a cross-sectional view of the leg assembly of the frame assembly of FIG. 2 in the extended position.

FIG. 6B is a cross-sectional view of the leg assembly of the frame assembly of FIG. 2 in the retracted position.

FIG. 6C is a cross-sectional view of another leg assembly in the retracted position.

FIG. 7 is a localized view of a foot for a leg assembly of the frame assembly of FIG. 2.

FIG. 8 is a view of a prior art foot for a corner pole of a collapsible structure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention overcomes many of the prior art problems associated with collapsible shelters. The advantages, and other features of the system disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth representative embodiments of the present invention and wherein like reference numerals identify similar structural elements.

Referring to FIG. 1, a shelter 100 in accordance with the present disclosure includes a collapsible frame assembly 102 for mounting a canopy 104 thereon. The collapsible frame 102 is shown in the raised, unfolded or “set-up” position. The collapsible frame 102 includes four leg assemblies 106 adapted to rest on a support surface. It should be understood that a shelter 100 according to the subject disclosure may include more or less than four leg assemblies 106 to form configurations other than cubic. Preferably, each of the leg assemblies 106 is the same.

Referring now to FIG. 2, the frame assembly 102 includes a plurality of eave assemblies 108 extending between each pair of leg assemblies 106. A plurality of truss assemblies 110 extend from the midpoint of the eave assembiles 108 to pivotally connect to a center apex assembly 112. The combination of the eave assemblies 108 and truss assemblies 110 combine to support the center post assembly 112 to insure that the canopy 104 is maintained taut thereon. Each eave assembly 108 and truss assembly 110 is preferably the same. For simplicity, the following description is with respect to a single assembly. The eave assembly 108 includes a pair of neighboring scissor units 114a,114b, each scissor unit 114a,114b having a first cross piece 116 and a second cross piece 118. The cross pieces 116, 118 are pivotally connected about their midpoints 115. On one end, each scissor unit 114 pivotally attaches to a leg assembly 106. On the other end, the neighboring scissor units 114a,114b are pivotally connected. Where the neighboring scissor units 114a,114b are connected, a connector 120 selectively links together the first cross piece 116 and the second cross piece 118. The connector 120 prevents the end of the first cross piece 116 from moving away from the end of the second cross piece 118 at the ends where the neighboring scissor units 114a,114b are connected. As a result, the frame assembly 102 is well-suited to withstand downward pressure upon the eave assemblies 108.

As best seen in FIG. 3, the connector 120 is preferably a loop 122 of webbing and a buckle 124. A second loop 126 and buckle 128 of the connector 120 allow further linking to the canopy 104. In a preferred embodiment, the second loop 126 passes through a reinforced hole (not shown) in the canopy 104. In other preferred embodiments, hook and loop fabric, locking snaps, and the like are utilized to perform the selective coupling function of the connector 120.

Referring again to FIG. 2, the truss assembly 110 consists of a single scissor unit 130 having a first cross piece 134 and a second cross piece 132 that are pivotally connected substantially about respective midpoints 133. One end of the scissor unit 130 is pivotally coupled to the eave assembly 108 intermediate the scissor units 114a,114b. The other end of the scissor unit 130 is coupled to the center apex assembly 112. In a preferred embodiment, the second cross piece 132 is substantially horizontal so that headroom within the shelter 100 is improved. It is also envisioned that the frame assembly 102 could include truss, eave, and connector assemblies with more or less scissor units to achieve the desired configuration while still benefiting from the advantages of the subject disclosure.

Referring to FIG. 4, there is shown a localized view of the scissor units 130 coupled to the center apex assembly 112. The center apex assembly 112 includes a center post 136 having an upper end and a lower end. Preferably, the center post 136 telescopes and has a dome-shape at the upper end. A hub assembly 138 is slidingly mounted on the center post 136 intermediate the upper end and the lower end. The hub assembly 138 has a plurality of mounts 140 for pivotally connecting the cross pieces 134 of the scissor units 130 thereto. Preferably, the mounts 140 form a channel 142 in which the ends of the cross pieces 134 are retained by a nut and bolt combination 144. It should be noted that many suitable fasteners can be used for all pivotal connections of the collapsible frame 102. Such fasteners can be rivets, a locking bar and cotter pin combination, pintle, or other suitable fasteners.

Referring now to FIGS. 4, 5A and 5B, a locking button 146 on the center post 136 selectively prevents the center post 136 from sliding beyond the locking button 146 even when downward force is applied to the center post 136. A spring wire 148 within the center post 136 urges the locking button 146 outward but can be depressed to allow the locking button 146 to pass within the hub assembly 138 for folding of the frame assembly 102. It is envisioned that the locking button 146 may be placed at a variety of locations in order to provide the desired headroom. In an alternate embodiment, a locking button could be utilized on the hub assembly 138 to selectively engage a plurality of holes formed in the center post 136 to thereby vary the tension applied to the canopy 104.

When in the set-up position, the frame assembly 102 provides a structure with increased rigidity. The retention of the hub assembly 138 on the center post 136 causes the center post 136 and the cross pieces 132,134 of the scissor units 130 to form a supportive triangle. The supporting triangle allows for any lateral forces applied to the center post 136 to be opposed by the scissor units 130 rather than by a moment maintained by the joint 137 linking the center post 136 to the frame assembly 102. This transfer of the load bearing responsibility from the joint 137 to the scissor units 130 creates a more rigid and reliable structure. The other end of each scissor unit 130 is not only pivotally linked to the eave assembly 108 but also incorporates a vertically coupling of the cross pieces 132,134 by the connector 120 to form a second triangle. The second triangle prevents the end of the first cross piece 134 from moving away from the end of the second cross piece 132 at the ends where the cross pieces 132,134 connect to the eave assembly 108. As a result, the frame assembly 102 is well-suited to withstand downward pressure upon the truss assemblies 110.

Referring now to FIGS. 6A and 6B, an exemplary leg assembly 106 is shown in vertical cross-section. The leg assembly 106 includes a top portion 150, a middle portion 152 and a bottom portion 154. The middle portion 152 and the bottom portion 154 telescope within the top portion 150 to reduce the height of the leg assembly 106 for storage and transport. Additionally, it is possible to extend only one portion in order to vary the overall height of the frame assembly 102 above the support surface. In another preferred embodiment, the leg assembly 106 includes additional portions to further allow variation of the height thereof. A locking button 156 on the bottom portion 154 selectively engages a hole formed in the middle portion 152 to fix the relative positions of the bottom and middle portions 154, 152 when in an extended position. Similarly, a locking button 156 on the middle portion 152 selectively engages a hole formed in the top portion 150 to fix the relative positions of the middle and top portions 152, 150 when in an extended position. A spring wire 158 urges each locking button 156 outward. To retract the leg assembly, each locking button 156 is depressed, thus allowing the middle and bottom portions 152, 154 to pass within the top portion 150. Preferably, the locking buttons 156 are not rounded but rather cylindrical and terminating in a flat surface. The flat surface allows for effective engagement of the hole even if the portion containing the hole is telescoped inside another portion. Thus, extension of the leg assembly 106 is easily done. Additionally, another button 157, urged by a wire 159 secures the scissor linkages 114 to the leg assembly 106 in the assembled position.

Referring now to FIG. 6C, as will be appreciated by those of ordinary skill in the pertinent art, the leg assembly 206 utilizes similar principles of the leg assembly 106 described above. Accordingly, like reference numerals preceded by the numeral “2” instead of the numeral “1”, are used to indicate like elements. The leg assembly 206 includes a top portion 250, a middle portion 252 and a bottom portion 254. A plurality of holes 269 are formed in the upper portion 250 to allow variation in fixing the relative positions of the bottom and middle portions 254, 252 with respect thereto. The middle portion 252 is longer in length than the top portion 250 so that the middle portion 252 always is accessible. The locking button 256 on the bottom portion 254 is secured to a different side of the square in horizontal cross-section leg assembly 206.

In another preferred embodiment, the leg assembly 106 defines a plurality of holes for receiving the locking buttons 156. As such, the portions 150,152,154 can be fixed in a variety of positions in addition to the extended position. Preferably, the hole or holes for fixing the middle portion 152 are offset with respect to the holes for fixing the bottom portion 154. Thus, the buttons 156 of the respective portions are not inadvertently engaged by the wrong hole. In still another preferred embodiment, the cross-section of the leg assembly 106 is square and the hole(s) for engaging each portion 152, 154 are formed in different sides of the square.

Referring now to FIG. 7, a foot 160 of a leg assembly 106 is shown in detail. The foot 160 has a curved outer rim 162 for preventing the leg assembly 106 from binding or digging into the support surface during folding and assembling of the frame assembly 102. The foot 160 defines holes 164 for anchoring the foot 160, and, thereby, the frame assembly 102, to the support surface.

While the invention has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the invention without departing from the spirit or scope of the invention as defined by the appended claims.