Patent ID: 8020822

Claim:
An adjustable shelf assembly comprising: at least one rib cam having a longitudinal axis and a slot including a floor disposed perpendicularly to said longitudinal axis, at least one rib having a flat top retaining surface, a generally T-shaped downwardly opening aperture, and two inwardly extending opposing rib cam flanges, said aperture having an upper portion and a lower portion, said upper portion having two opposing upper recesses and an upper edge extending between said recesses, said lower portion bounded laterally by said rib cam flanges, said rib cam flanges each having an arced inner edge, said arced inner edge having upper and lower portions and a middle portion between said upper and lower portions, a support beam having a substantially I-shaped profile, two upper beam flanges, two lower beam flanges, an upper beam flange face, and two outwardly facing annular channels, each channel having a concave surface, said upper beam flanges of said beam slidably received in said upper recesses of said aperture and said upper beam flange face of said support beam in sliding engagement with said upper edge of said aperture such that said rib is captured on said beam, each of said rib cam flanges extending into a respective one of said channels, said arced inner edges of said rib cam flanges and said concave surfaces of said annular channels forming crescent-shaped profiles, the distance between said inner edge of said rib cam flanges and said concave surface of said annular channels being greater at said middle portion than at said upper or lower portions, said rib cam rotatably received in one of said channels with one of said rib cam flanges captured in said slot and said floor of said slot in abutting engagement with said arced inner edge of said rib cam flange, one of said upper beam flanges disposed adjacent to said rib cam, said rib cam rotatable around said longitudinal axis between an unlocked position and a locked position, in said unlocked position said floor of said slot tangentially abutting said middle region of said inner edge of said rib cam flange, said rib cam being slidable in one of said annular channels along said beam, and said rib being slidable longitudinally along said beam, and in said locked position said floor abutting one of said upper and lower portions of said inner edge of said rib cam flange thereby tightening said floor against said inner edge of said rib cam flange, thereby pressing said upper edge of said upper portion of said aperture against said upper beam flange face of said support beam, and biasing said adjacently disposed upper beam flange into one of said upper recesses of said aperture of said rib, such that said rib cam is fixed in said annular channel, and said rib is secured in place on said beam.