Collapsible child pen with improved hinge joint

In a child pen comprising a collapsible structure having a plurality of structural members which are coupled to one another and which are moveable relative to one another to assemble the structure from a collapsed condition and to collapse the structure from an assembled condition, the improvement comprising a hinge joint comprising a longitudinally extending yoke member including means defining an opening in a longitudinal end thereof, a longitudinally extending rod member having a longitudinal end portion disposed partially within said opening in said yoke, the longitudinal axes of said yoke and said rod member lying in a substantially common plane, means forming a pivot axis extending normal to the longitudinal axis of the rod member, means supporting said pivot axis in a fixed position with respect to said yoke member, said rod member being supported for pivotal movement in a first direction about said pivot axis during assembling of the structure whereby said rod member is brought into longitudinal alignment with said yoke member and in a second direction about said axis during collapsing of said structure, a cap member interconnected with said yoke member and said pivot axis and supported for pivotal movement about said pivot axis during assembly and collapse of said structure, said yoke defining means for resisting movement of said cap member in the direction of said pivot axis, means for interconnecting said cap member and said longitudinal end of said rod member for joint pivotal movement about said pivot axis during assembly and collapse of said structure, said cap member including outer surface means disposed at least partially within said opening and moveable along a path disposed in covering relation to said opening to prevent longitudinal insertion of a human limb such as a finger into said opening during pivotal movement of said rod member from said collapsed condition to said assembled condition.