Abstract: A joint for interconnecting confronting end portions of two elongate members so that the elongate members are movable between first and second positions. In the first position, the elongate members are releasably locked in a coaxial, erect supporting position in which confronting end portions of the members are closely spaced from each other. In the second position, the elongate members are spaced from and substantially parallel to each other. The hinge includes a central block member having a generally U-shaped profile, with guide surfaces and cam slots in its flanges. Guide members having similarly shaped guide surfaces and cam slots are connected in pairs to opposite ends of the block member and cooperate with the guide surfaces and cam slots to control movement of the tubular members between the first and second positions.

Abstract: A collapsible folding cart movable between an erected condition and a collapsed condition. The cart has front, side, and rear frameworks interconnected by corner posts. A bottom framework is connected to bottom portions of the front, side, and rear frameworks. Handles are connected to sides of the cart in such manner that the handles can be moved between a diagonal position when the cart is erected and a position substantially parallel to the axes of the corner posts when the cart is collapsed. Lower corner portions of the front and side frameworks and lower portions of the rear and side frameworks are interconnected to each other in such manner that, during collapse of the cart, the breadth and width of the cart are simultaneously reduced. The various components of the cart are interconnected in such manner that the frameworks are collapsible to reduce the overall breadth and width of the cart, and to increase the length of the collapsed cart.

Abstract: A collapsible support structure for a folding sled. The support structure, in an erect position, has two vertical members interconnected at their bottoms by a collapsible, preferably horizontal, member. Each end of the horizontal member is also pivotally connected to the other vertical member by a diagonal support member that extends between each end of the horizontal member and an upper portion of the opposite vertical member. When the structure is erect, the diagonal support members form an "X". Stiffening members, which are preferably generally vertical, are spaced from the vertical members and extend between the horizontal member and the diagonal support members. Both the horizontal member and the diagonal support members are formed of a plurality of pivotally interconnected links, at least one of which is modified to maintain the links in a desired angular position when the support structure is erected.

Abstract: A collapsible support structure for supporting items, such as chair backs. The support structure, in an erect position, has two vertical members interconnected at their bottoms by a collapsible, preferably horizontal, member. Each end of the horizontal member is also pivotally connected to the other vertical member by a diagonal support member that extends between each end of the horizontal member and an upper portion of the opposite vertical member. When the structure is erect, the diagonal support members form an "X". Stiffening members, which are preferably generally vertical, are spaced from the vertical members and extend between the horizontal member and the diagonal support members. Both the horizontal member and the diagonal support members are formed of a plurality of pivotally interconnected links, at least one of which is modified to maintain the links in a desired angular position when the support structure is erected.

Abstract: An improved collapsible support structure having, in an erect position, a pair of vertical members interconnected by at least one collapsible or foldable support mechanism. The collapsible support mechanism has upper and lower substantially horizontal collapsible connecting members that are interconnected by diagonal support members forming an "X" positioned approximately halfway between the pair of vertical members. Each of the horizontal members is formed of a plurality of pivotally interconnected elements and at least one of the elements of one of the members is modified to maintain a desired angular relationship between the elements. A plurality of the collapsible support structures are combined together or interconnected to form improved collapsible or folding devices.