Patent ID: 8398038

Claim:
A pivotable assembly mounted above a support surface and within an opening in a wall, the assembly comprising: a pivotable system; an arm having a pivot with a pivot axis oriented normal to the support surface, said pivotable system attached to said arm, said arm having a first end mounted at the pivot and a second end spaced away from the pivot, the arm being disposed within an opening and extending across a span of the opening, the first end of the arm being pivotably connected proximate a first boundary of the opening, and the second end of the arm being removably connected proximate a second boundary of the opening; a wheel support attached to said pivotable system at a position spaced from said pivot axis, said wheel support comprising: an extension member having a longitudinal axis and an aperture running transversely through said extension member, said extension member extending generally downwardly from the pivotable system; a bushing fixed to said extension member, said bushing having an inner bore that is at least partially threaded; a yoke having a threaded shaft with an elongate slot therethrough, said yoke threadably received within the inner bore of said bushing so that said yoke is vertically adjustable with respect to said extension member; a pin sized to be receivable in said aperture and in said slot, said yoke being rotationally and vertically fixed with respect to said extension member when said pin is received within said slot; and a wheel having an axis of rotation substantially normal to the longitudinal axis of the extension member, said wheel rotatably attached to said yoke, wherein said wheel is vertically adjustable with respect to said extension member; wherein said wheel of said wheel support is vertically adjusted to define a gap between said support surface and said wheel when said arm is connected proximate the second boundary of the opening, the gap sized so that said wheel touches the support surface when said second end of said arm is not connected proximate the second boundary of the opening; wherein said wheel support is attached to said pivotable system via a mounting bracket having a mounting plate portion and a mounting tube portion, said extension member being mounted to said mounting tube portion and said pivotable system being mounted to said mounting plate portion.