Lighting fixture

1. A lighting fixture comprising:

a light emitting element mounting assembly;

at least a first set of rails, said first set of rails comprising a first rail and a second rail, said first rail and second rail each being connected to said light emitting element mounting assembly, at least one of said first rail and said second rail being slidable relative to said light emitting element mounting assembly, said first rail having a major dimension extending in a first direction, said second rail having a major dimension extending in a second direction, said first direction being substantially parallel to said second direction, said first rail being slidable relative to said second rail along said first direction, said first rail and said second rail each being extruded, said first rail having a first profile, said first profile comprising a first profile male component and a first rail female component, said second rail having a second profile, said second profile comprising a second profile male component and a second rail female component, said first profile male component being positioned within said second profile female component, said second profile male component being positioned within said first profile female component, wherein said second profile would be substantially similar to said first profile if said first profile were rotated 180 degrees.

2. A lighting fixture as recited in claim 1 , wherein said first rail and said second rail each have a beam structure in both up-down and side-to-side bending.

3. A lighting fixture as recited in claim 1 , wherein said first and second rails together have a combined external profile which is substantially rectangular.

4. A lighting fixture as recited in claim 1 , wherein said lighting fixture further comprises a receiving structure to which a light emitting element can be connected.

5. A lighting fixture as recited in claim 1 , wherein said lighting fixture further comprises a light emitting element.

6. A lighting fixture as recited in claim 1 , wherein said lighting fixture further comprises at least one stop which prevents said first profile male component from sliding completely out of said second profile female component and which prevents said second profile male component from sliding completely out of said first profile female component.

7. A lighting fixture as recited in claim 1 , wherein said first and second rails together have a combined external profile which is free from angles in excess of 90 degrees.

8. A lighting fixture as recited in claim 1 , wherein said first rail female component extends greater than 180 degrees around said second rail male component, and said second rail female component extends greater than 180 degrees around said first rail male component.

9. A lighting fixture as recited in claim 1 , wherein said lighting fixture further comprises at least one engagement element, said engagement element being attached to said light emitting element mounting assembly, said engagement element comprising at least a first engagement element portion and a second engagement element portion, said first engagement element portion being in contact with a first portion of said first rail, said second engagement element portion being in contact with a first portion of said second rail.

10. A lighting fixture as recited in claim 9 , wherein said engagement element comprises a support element, a first pad and a second pad, said first pad being mounted on a first portion of said support element, said second pad being mounted on a second portion of said support element, said first pad comprising said first engagement element portion and being in contact with said first portion of said first rail, said second pad comprising said second engagement element portion and being in contact with said first portion of said second rail.

11. A lighting fixture comprising:

a light emitting element mounting assembly comprising an opening through which a light engine housing can be inserted, said light emitting element mounting assembly comprising at least one of (1) at least one spring clip and (2) at least one clip engagement structure.

12. A lighting fixture as recited in claim 11 , wherein said clip engagement structure comprises at least one slot.

13. A lighting fixture as recited in claim 11 , wherein said lighting fixture further comprises a light emitting element received in said opening.

14. A lighting fixture as recited in claim 13 , wherein said light emitting element mounting assembly comprises at least a first spring clip, and said light emitting element comprises at least a first clip engagement structure, said first clip engagement structure comprising a plurality of clip engagement regions, said first spring clip engaging one of said clip engagement regions.

15. A lighting fixture as recited in claim 14 , wherein at least a first pair of clip engagement regions are spaced from each other by a distance which is less than one-tenth of a major dimension of said light engine housing.

16. A lighting fixture as recited in claim 13 , wherein said light emitting element comprises at least a first spring clip, and said light emitting element mounting assembly comprises at least a first clip engagement structure, said first clip engagement structure comprising a plurality of clip engagement regions, said first spring clip engaging one of said clip engagement regions.

17. A lighting fixture as recited in claim 16 , wherein at least a first pair of clip engagement regions are spaced from each other by a distance which is less than one-tenth of a major dimension of said light engine housing.

18. A lighting fixture comprising:

a light emitting element mounting assembly;

at least a first set of rails, said first set of rails comprising a first rail and a second rail, said first rail and second rail each being connected to said light emitting element mounting assembly, at least one of said first rail and said second rail being slidable relative to said light emitting element mounting assembly, said first rail having a major dimension extending in a first direction, said second rail having a major dimension extending in a second direction, said first direction being substantially parallel to said second direction, said first rail being slidable relative to said second rail along said first direction; and

at least a first supplemental rail, said first supplemental rail being slidable relative to said light emitting element mounting assembly along a third direction, said third direction being parallel to said first direction.

19. A lighting fixture comprising:

a light emitting element mounting assembly;

at least a first set of rails, said first set of rails comprising a first rail and a second rail, said first rail and second rail each being connected to said light emitting element mounting assembly, at least one of said first rail and said second rail being slidable relative to said light emitting element mounting assembly, said first rail having a major dimension extending in a first direction, said second rail having a major dimension extending in a second direction, said first direction being substantially parallel to said second direction, said first rail being slidable relative to said second rail along said first direction; and

at least one engagement element, said engagement element being attached to said light emitting element mounting assembly, said engagement element comprising at least a first engagement element portion and a second engagement element portion, said first engagement element portion being in contact with a first portion of said first rail, said second engagement element portion being in contact with a first portion of said second rail.

20. A lighting fixture as recited in claim 19 , wherein said engagement element comprises a support element, a first pad and a second pad, said first pad being mounted on a first portion of said support element, said second pad being mounted on a second portion of said support element, said first pad comprising said first engagement element portion and being in contact with said first portion of said first rail, said second pad comprising said second engagement element portion and being in contact with said first portion of said second rail.

21. A lighting fixture as recited in claim 20 , wherein said support element is spring biased such that said first pad exerts force on said first portion of said first rail and said second pad exerts force on said first portion of said second rail.

22. A lighting fixture as recited in claim 21 , wherein said support element further comprises a tensioning element which can be tightened to increase the force exerted by said first pad on said first portion of said first rail and to increase the force exerted by said second pad on said first portion of said second rail.

23. A lighting fixture as recited in claim 20 , wherein said support element further comprises a tensioning element which can be tightened to cause said first pad to exert force on said first portion of said first rail and said second pad to exert force on said first portion of said second rail.