A door assembly for a shelter, wherein the shelter comprises a frame assembly and a cover for covering the frame assembly, wherein the door assembly includes a door frame; a door coupled to the door frame, wherein the door is preferably of a flexible material that can be lifted to provide an opening into the shelter and can be lowered for enclosing the shelter, wherein the door includes a plurality of pockets; a plurality of elongated door members, each of which includes a first and a second end, wherein each of the plurality of elongated door members is positioned within a respective one of the pockets; a plurality of first couplers, each of which couples the first end of a respective elongated door member to a first side of the door frame; a plurality of second couplers, each of which couples the second end of a respective elongated door member to a second side of the door frame; and a door lifting/lowering assembly for lifting the door to provide the opening into the shelter and for lowering the door for enclosing the shelter. Also disclosed herein is a shelter comprising a frame assembly and a cover for covering the frame assembly; and a door assembly as disclosed above.

Provided is an adjustable barrier having a central hinge having a cylindrical post and an axis of rotation; a first expandable section coupled to the cylindrical post of the central hinge by at least a first connector; and a second expandable section coupled to the cylindrical post of the central hinge by at least a second connector. At least one of the first and second expandable sections is configured to articulate around the axis of rotation of the central hinge forming an articulation angle between the first and second expandable sections.

A door assembly for a shelter, wherein the shelter comprises a frame assembly and a cover for covering the frame assembly, wherein the door assembly includes a door frame; a door coupled to the door frame, wherein the door is preferably of a flexible material that can be lifted to provide an opening into the shelter and can be lowered for enclosing the shelter, wherein the door includes a plurality of pockets; a plurality of elongated door members, each of which includes a first and a second end, wherein each of the plurality of elongated door members is positioned within a respective one of the pockets; a plurality of first couplers, each of which couples the first end of a respective elongated door member to a first side of the door frame; a plurality of second couplers, each of which couples the second end of a respective elongated door member to a second side of the door frame; and a door lifting/lowering assembly for lifting the door to provide the opening into the shelter and for lowering the door for enclosing the shelter. Also disclosed herein is a shelter comprising a frame assembly and a cover for covering the frame assembly; and a door assembly as disclosed above.

A cover for covering an opening defined in a surface, the opening defined between a first edge and a second edge, and defining an opening width therebetween, shorter than a length of the opening, the cover having a cover width and configured to be supported, in use, at the first edge and the second edge of the opening when the cover width is parallel to the opening width, wherein the cover width is adjustable from a first cover width to a second cover width, and wherein the cover is configured to maintain the cover width at the second cover width, in use.

Provided is an adjustable barrier having a central hinge having a cylindrical post and an axis of rotation; a first expandable section coupled to the cylindrical post of the central hinge by at least a first connector; and a second expandable section coupled to the cylindrical post of the central hinge by at least a second connector. At least one of the first and second expandable sections is configured to articulate around the axis of rotation of the central hinge forming an articulation angle between the first and second expandable sections.