Back frame

Abstract

A back frame that includes a first part and a second separate part configured to disengagingly interlock at plural relative positions to define respective assembled configurations of the back frame of two or more distinct lengths, whereby the back frame is adjustable for wearers of different heights. The interlocking includes releasably interengaging the first and second parts by relatively moving the first and second parts in a first direction generally toward each other and then in a second direction generally perpendicular to the first direction.

1 . A back frame comprising:
 a first part and a second separate part configured to disengagingly interlock at plural relative positions to define respective assembled configurations of the back frame of two or more distinct lengths, whereby the back frame is adjustable for wearers of different heights;   wherein said interlocking includes releasably interengaging the first and second parts by relatively moving the first and second parts in a first direction generally toward each other and then in a second direction generally perpendicular to the first direction,   
     
     
         2 . The back frame of  claim 1  configured whereby said relative movement of the first and second parts in the second direction comprises the first and second parts sliding over each other. 
     
     
         3 . The back frame of  claim 1 , including one or more first formations on one of the first and second parts and a plurality of second formations on the other of the first and second parts, the or each first formation selectively engaging the respective second formations to define the respective assembled configurations of the back frame when the first and second parts are releasably interengaged. 
     
     
         4 . The back frame of  claim 3 , wherein the first and second formations are disengaged by relatively moving the first and second parts in a direction opposite to the second direction and then in a direction opposite to the first direction. 
     
     
         5 . The back frame of  claim 3 , wherein the first and second parts of the back frame are wholly separable when the first and second formations are disengaged. 
     
     
         6 . The back frame of  claim 2 , wherein the first formation comprises a projecting locking formation and the second formations comprise apertures, wherein when the first and second parts are relatively moved in the first direction the projecting locking formation is received in a selected opposed said aperture. 
     
     
         7 . The back frame of  claim 6 , wherein the first part of the back frame include a said locking formation and the second part of the back frame includes a said plurality of the opposed apertures. 
     
     
         8 . The back frame of  claim 7 , wherein, the second part of the back frame includes a said locking formation and the first part of the back frame includes a further said plurality of apertures. 
     
     
         9 . The back frame of  claim 6 , wherein the or each locking formation comprises a generally L-shaped projection which slidingly engages a peripheral wall of the respective opposed aperture so as to be releasably wedged therein. 
     
     
         10 . The back frame of  claim 9 , wherein the or each L-shaped projection is adapted to slidingly engage the peripheral wall of the respective opposed aperture by relatively sliding the first and second parts of the back frame over each other in said second direction. 
     
     
         11 . The back frame of  claim 6 , wherein there are four of said locking formations arranged in a rectangular array. 
     
     
         12 . The back frame of  claim 11 , wherein the first and second parts each include a pair of spaced generally parallel side rails and one or more spaced cross-structures joining the side rails, wherein each side rail has therethrough a plurality of said apertures arranged in a linear array along the respective side rail. 
     
     
         13 . The back frame of  claim 12 , wherein one of the one or more spaced cross-structures has, integrally formed therewith at a position between the side rails, a lumbar support member that projects without further support from the one cross-structure so as to be inclined to a plane, optionally curved, containing the side rails. 
     
     
         14 . The back frame of  claim 1 , further including a releasable latch arrangement that must be released in a first action to allow disengagement of the first and second parts from interlocking engagement. 
     
     
         15 . The back frame of  claim 3 , further including a releasable latch arrangement that must be released in a first action to allow disengagement of the first and second parts, wherein the latch arrangement comprises one or more further locking formations located on one of said parts which further locking formation is receivable within plural said apertures of the other part and when therein abuts a peripheral wall of the respective aperture when the first and second parts are interengaged thereby preventing relative sliding between the first and second parts, and thereby interlocking the first and second parts. 
     
     
         16 . The back frame of  claim 15 , wherein the or each further locking formation is provided on a respective tab configured to be resiliently flexed in said first action. 
     
     
         17 . The back frame of  claim 15 , including a pair of said latch arrangements at respective sides of the back frame. 
     
     
         18 . The back frame of  claim 1 , wherein the first and second parts are curved so as to follow or approximate a typical curvature of a wearer's back. 
     
     
         19 . The back frame of  claim 1 , wherein the first and second parts are respective unitary single mouldings. 
     
     
         20 . A back frame comprising:
 a pair of spaced generally parallel side rails that define a plane, optionally curved, containing the side rails; and   one or more spaced cross-structures joining the side rails, wherein one of the one or more spaced cross-structures has, integrally formed therewith at a position between the side rails, a lumbar support member that projects without further support from the one cross-structure so as to be inclined to said plane;   wherein the lumbar support member and the one cross-structure are dimensioned so that the lumbar support member contacts a lumbar region of a wearer's back when the back frame is being worn, and are configured so that the lumbar support member is able to elastically flex during said contact.   
     
     
         21 . The back frame of  claim 20 , wherein the lumbar support member is generally of inverted U-shape and is upstanding from the one cross-structure when the back frame is worn in a correct orientation. 
     
     
         22 . The back frame of  claim 14 , including a pair of said latch arrangements at respective sides of the back frame. 
     
     
         23 . The back frame of  claim 10 , wherein there are four of said locking formations arranged in a rectangular array. 
     
     
         24 . The back frame of  claim 23 , wherein the first and second parts each include a pair of spaced generally parallel side rails and one or more spaced cross-structures joining the side rails, wherein each side rail has therethrough a plurality of said apertures arranged in a linear array along the respective side rail.