Collapsible frame structures

1. A collapsible frame comprising:

two or more frame members adapted to be joined to form a frame;

an elastic cord extending interiorly through said frame members for pulling said frame members together when the frame members are aligned to facilitate assembly of the frame; and

a non-elastic tension cable extending interiorly through said frame members; and

a tensioning device connected to said tension cable for tensioning said tension cable when the frame is assembled to enhance the strength of the assembled frame.

2. The collapsible frame according to claim 1 wherein the tensioning device is rotatable and includes an arcuate track to receive said tension cable, and wherein said tension cable extends around said arcuate track such that rotation of said tensioning device in a first direction tensions said tension cable and wherein rotation of said tensioning device in a second direction loosens said tension cable.

3. The collapsible frame of claim 1 comprising two frame sections pivotally connected to one another.

4. The collapsible frame of claim 3 wherein each frame section includes a tension cable and wherein said tensioning device tensions both of said first and second tension cables.

5. The collapsible frame of claim 4 wherein the tensioning device pivotally connects said first and second frame sections.

6. The collapsible frame of claim 4 wherein said tensioning device includes first and second tensioning members rotatably connected to one another for tensioning respective ones of said tension cables.

7. The collapsible frame of claim 4 wherein each frame section includes a tension cable and a tensioning member.

8. The collapsible frame of claim 7 wherein the tensioning members for each frame section are rotatably connected to one another.

9. A tensioning device for removing slack from a cable, said tensioning device comprising:

a housing including first and second rotatable housing sections;

a cable entry for allowing a cable to enter said housing;

an arcuate cable track within said housing around which said cable passes;

a guide pulley in said housing to guide said cable into said cable track; and

said cable track and cable entry arranged such that relative rotation of said housing sections in a first direction removes slack from said cable, and that relative rotation of said housing sections in a second direction introduces slack into said cable.

10. A tensioning device for removing slack from a cable, said tensioning device comprising:

a housing including first and second rotatable housing sections;

a first cable entry for allowing a first cable to enter said housing;

a second cable entry for allowing a second cable to enter said housing;

a first and second arcuate cable tracks within said housing around which said cables pass; and

said cable tracks and cable entries arranged such that relative rotation of said housing sections in a first direction removes slack from said cables, and that relative rotation of said housing sections in a second direction introduces slack into said cables.

11. The tensioning device of claim 10 wherein each cable is fixed at one end to a respective housing section.

12. The tensioning device of claim 10 wherein each cable enters said housing through a respective cable entry in a respective housing section and passes around the cable track in the opposite housing section.

13. The tensioning device of claim 12 wherein each cable is fixed at one end to a respective housing section.

14. The tensioning device of claim 13 further comprising a pair of guide pulleys mounted to respective housing sections to guide said cables into said cable tracks.