Abstract: This invention provides an arcuate frame rib for the frame of a covered shelter. The arcuate rib includes an adjustable and pivotal base mounting at each end of the arc. The rib is formed by sections of tubing joined by a rigid coupler having an angled upper member with tube receivers at both ends to slideably receive the tubular sections, a lower member with tube guides at both ends to slideably receive and guide the tubular sections received in the tube receivers and a central body member joining the upper and lower members. The lower member generally includes a reinforcement that carries a double assembly pin receiving tab. Rib braces generally connect the lower members of successive rigid couplers to support the rib by being pinned to the double pin receiving tabs. For further reinforcement, there are generally knee braces formed of knee tubing strengthened by a gussett plate and clamped to the rib braces.

Abstract: A generally rectangular shelter with a readily assembled frame mounted on a base and covered with a flexible sheet material secured to the frame and base is provided. The base is normally of wood and is placed on the ground or other planar surface Spaced at a desirable distance along each side of the base are pivotal and adjustable supports fixed to the base. To the supports are connected a series of assembled frame ribs transverse to the length of shelter. The frame ribs are normally assembled in an arcuate shape from several pieces of tubing coupled together by a special coupler. The tubes are adapted to receive other tubes by having pin receiving tabs welded to them in appropriate places. Purlins or other spacers are connected between the frame ribs so that all the frame ribs may be drawn up from an assembled horizontal position to an upright position as a unit.