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CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     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  
       [0002]     1. Field of the Invention  
         [0003]     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.  
         [0004]     2. Background of the Related Art  
         [0005]     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.  
         [0006]     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).  
         [0007]     For example, U.S. Pat. No. 4,779,635 (&#39;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 (&#39;726 patent) discloses an eave assembly for a collapsible shelter. The eave assembly of the &#39;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 &#39;726 patent is relatively strong compared to that of the &#39;635 patent. However, the &#39;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.  
         [0008]     The structure  10  of the &#39;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.  
         [0009]     The canopy structure  10  of the &#39;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  
       [0010]     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.  
         [0011]     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.  
         [0012]     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.  
         [0013]     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.  
         [0014]     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.  
         [0015]     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.  
         [0016]     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.  
         [0017]     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  
       [0018]     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.  
         [0019]      FIG. 1  is a perspective view of an assembled collapsible shelter constructed in accordance with a preferred embodiment of the subject disclosure.  
         [0020]      FIG. 2  is a perspective view of the frame assembly of the shelter of  FIG. 1 .  
         [0021]      FIG. 3  is a localized view of the scissor-type linkage of the frame assembly of  FIG. 2 .  
         [0022]      FIG. 4  is a localized view of the center coupling of the frame assembly of  FIG. 2 .  
         [0023]      FIG. 5A  is a cross-sectional view of the center coupling assembly of the frame assembly of  FIG. 2  in the disassembled position.  
         [0024]      FIG. 5B  is a cross-sectional view of the center coupling assembly of the frame assembly of  FIG. 2  in the assembled position.  
         [0025]      FIG. 6A  is a cross-sectional view of the leg assembly of the frame assembly of  FIG. 2  in the extended position.  
         [0026]      FIG. 6B  is a cross-sectional view of the leg assembly of the frame assembly of  FIG. 2  in the retracted position.  
         [0027]      FIG. 6C  is a cross-sectional view of another leg assembly in the retracted position.  
         [0028]      FIG. 7  is a localized view of a foot for a leg assembly of the frame assembly of  FIG. 2 .  
         [0029]      FIG. 8  is a view of a prior art foot for a corner pole of a collapsible structure. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0030]     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.  
         [0031]     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.  
         [0032]     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  114   a,   114   b,  each scissor unit  114   a,   114   b  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  114   a,   114   b  are pivotally connected. Where the neighboring scissor units  114   a,   114   b  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  114   a,   114   b  are connected. As a result, the frame assembly  102  is well-suited to withstand downward pressure upon the eave assemblies  108 .  
         [0033]     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 .  
         [0034]     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  114   a,   114   b.  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.  
         [0035]     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.  
         [0036]     Referring now to  FIGS. 4, 5A  and  5 B, 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 .  
         [0037]     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 .  
         [0038]     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.  
         [0039]     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 .  
         [0040]     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.  
         [0041]     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.  
         [0042]     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.

Summary:
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.