Retractable apparatus for supporting an element

Claim 2

Retractable apparatus for supporting an element, said apparatus comprising: elongated first support means for attachment to a supporting frame and having a first engagement portion; and elongated second support means adapted to mount an element to be supported and having a second engagement portion, said second support means being movable in a longitudinal path generally parallel to said first support means and between a retracted position and an extended position relative to said first support means, said second engagement portion being out of longitudinal alignment and freely movable relative to said first engagement portion during movement of said second support means along said longitudinal path, said first and second engagement portions being adjacent in said extended position, said second support means in said extended position being laterally movable relative to said first support means to locate said first and second engagement portions in general longitudinal alignment whereby longitudinal movement of said second support means toward said retracted position engages said first and second engagement portions in overlapping, locked relation and thereby prevents lateral movement of said second support means and also prevents further longitudinal movement of said second support means toward said retracted position.

Claim 3

Retractable apparatus according to claim 1 wherein said first support means is tubular and said second support means is slidably movable within said first support means during movement of said second support means along said longitudinal path.

Claim 4

Retractable apparatus according to claim 1 wherein said first support means includes a first elongated member having an opening adjacent one extremity, and said second support means includes a second elongated member telescopably movable along said longitudinal path within said first member, an edge of said opening constituting said first engagement portion, and said second engagement portion constituting a portion of an end of said second member.

Claim 5

Retractable apparatus according to claim 1 wherein said first support means includes a flat wall, and said second support means includes a length of tubing telescopably movable along said longitudinal path adjacent said flat wall, said flat wall including an opening adjacent one extremity, the lower edge defining said opening constituting said first engagement portion, and the lower edge of the lower end of said length of tubing constituting said second engagement portion, said lower edge of said length of tubing being adapted to fit over said lower edge of said opening in said locked relation.

Claim 6

Retractable apparatus according to claim 4 wherein said lower edge of said opening is inwardly deformed for slidable engagement with the adjacent wall of said length of tubing.

Claim 7

Retractable apparatus according to claim 4 wherein the upper portion of said flat wall in inwardly deformed for slidable engagement with the adjacent wall of said length of tubing.

Claim 8

Retractable apparatus according to claim 4 wherein said first support means includes a pair of walls adjacent said flat wall, and including a pair of opposed friction elements mounted to the interior surfaces of said pair of walls for slidable engagement with the adjacent walls of said length of tubing.

Claim 9

Retractable apparatus according to claim 7 wherein said length of tubing is rectangular in cross section, and including a pair of stop elements mounted to the exterior surfaces of a pair of opposite side walls of said length of tubing for engagement with said pair of friction elements, respectively, in said extended position.

Claim 10

Retractable apparatus for supporting an element, said apparatus comprising: a first length of tubing having adjacent one extremity a first engagement portion; and a second length of tubing having adjacent one extremity a second engagement portion, said second length being telescopably slidable within said first length in a longitudinal path generally parallel to the longitudinal axis of said first length, and between a retracted position and an extended position relative to said first length, said second engagement portion being out of longitudinal alignment and freely movable relative to said first engagement portion during movement of said second length along said longitudinal path, said first and second engagement portions being adjacent in said extended position, said second length in said extended position, being laterally movable relative to said first length to locate said first and second engagement portions in general longitudinal alignment whereby longitudinal movement of said second length toward said retracted position engages said first and second engagement portions in overlapping, locked relation and thereby prevents lateral movement of said second length and also prevents further longitudinal movement of said second length toward said retracted position, one of said first and second lengths being adapted for connection to a supporting frame and the other of said lengths being adapted to mount an element to be supported.

Claim 11

Retractable apparatus for supporting an element, said apparatus comprising: a first length of tubing having adjacent one extremity a first engagement portion; and a second length of tubing having adjacent one extremity a second engagement portion, said second length being telescopably slidable within said first length in a longitudinal path generally parallel to the longitudinal axis of said first length, and between a retracted position and an extended position relative to said first length, said second engagement portion being out of longitudinal alignment and freely movable relative to said first engagement portion during movement of said second length along said longitudinal path, said first and second engagement portions being adjacent in said extended position, said second length in said extended position, being laterally movable relative to said first length to locate said first and second engagement portions in general longitudinal alignment whereby longitudinal movement of said second length toward said retracted position engages said first and second engagement portions in overlapping, locked relation and thereby prevents lateral movement of said second length and also prevents further longitudinal movement of said second length toward said retracted position, one of said first and second lengths being adapted for connection to a supporting frame and the other of said lengths being adapted to mount an element to be supported.

Claim 12

Retractable apparatus according to claim 9 wherein said first and second lengths are each made of square tubing.

Claim 13

Retractable apparatus according to claim 10 wherein said first engagement portion comprises an edge of an opening formed in a first wall of the four walls of said first length, said second engagement portion comprises the end edge of a first wall of the four walls of said second length, said edge of said second length being adapted to fit over said edge of said first length in said locked position.

Claim 14

Retractable apparatus according to claim 11 wherein said edge of said opening is less wide than said edge of said first wall whereby said edge of said opening fits within the lower end of said second length in said locked relation.

Claim 15

Retractable apparatus according to claim 10 wherein said first length includes an opening in a first wall of its four walls, an edge of said opening constituting said first engagement portion, the lower edge of an end of said second length constituting said second engagement portion, said edges being adapted to interengage in said locked relation.

Claim 16

Retractable apparatus according to claim 13 wherein said first wall of said first length is inwardly deformed in an area spaced from said opening for slidable engagement with the adjacent wall of said second length.

Claim 17

Retractable apparatus according to claim 13 wherein said edge of said opening of said first length is inwardly deformed to define a shelf generally normal to the plane of said first wall for support of a wall of the lower end of said second length in said locked relation.

Claim 18

Retractable apparatus according to claim 11 and including a pair of opposed friction elements mounted to the interior surfaces of the pair of confronting side walls adjacent said first side wall of said first length for slidable engagement with the adjacent walls of said second length.

Claim 19

Retractable apparatus according to claim 15 and including a pair of stop elements mounted to the exterior surfaces of a pair of opposite side walls of said second length for engagement with said pair of friction elements, respectively, and establishing said extended position.

Claim 20

Retractable apparatus according to claim 13 wherein portions of the pair of walls adjacent said lower edge of said end of said second length are cut away to define recesses for reclining said edge of said opening of said first length in said locked relation.

Claim 21

Retractable apparatus according to claim 9 wherein said second engagement portion comprises a projection on the outer surface of said second length, and said first engagement portion comprises an end edge of said first length, said projection being adapted to fit over said end edge in said locked relation.