Patent ID: 7621489

Claim:
An extension and retraction arrangement for enabling an adjustment of a supported article from a retracted configuration to an extended configuration, the extension and retraction arrangement comprising: a trolley structure; a support arm for retaining an article to be supported in relation to the trolley structure wherein the support arm has a proximal portion coupled to the trolley structure and a distal portion for coupling to the article to be supported; an elongate support arrangement with a proximal end, a distal end, and a body portion wherein the elongate support arrangement comprises a first elongate support structure and a second elongate support structure disposed in spaced relation relative to the first elongate support structure wherein each of the first and second support structures has a dorsal side and a ventral side; and a means for supporting the trolley structure for axial extension and retraction along the body portion of the elongate support arrangement from adjacent to the distal end to adjacent to the proximal end of the elongate support arrangement wherein the trolley structure is slidably associated with the first and second elongate support structures, wherein the proximal portion of the support arm is disposed inboard of the first and second elongate support structures, and wherein the trolley structure has first and second portions slidably associated with the first and second elongate support structures and a centrally disposed alcove that is recessed in a dorsoventral direction in relation to the first and second portions and that is recessed between the first and second elongate support structures and wherein the proximal portion of the support arm is coupled to the centrally disposed alcove of the trolley structure; whereby the article to be supported and the trolley structure can be retained in a retracted configuration with the trolley structure disposed adjacent to the distal end of the elongate support arrangement and whereby the article and the trolley structure can be retained in an extended configuration with the trolley structure disposed adjacent to the proximal end of the elongate support arrangement.