Modular utility cart including improved structures for securing intermediate and top shelves to corner posts

A device for securing an element to a column, comprising:

• a sleeve having upper and lower edges, a right tubular inner surface for closely embracing said column, and a downwardly, outwardly inclined outer surface;
• and
• means cooperating with said element and defining a blind tubular collar having a downwardly outwardly inclined inner surface formed to mate with said outer surface of said sleeve, and an inwardly projecting retaining flange formed to underlie said lower edge of said sleeve when said outer surface of said sleeve and said inner surface of said collar are in mating relation,
• whereby downward movement of said collar about said sleeve on said column causes said retaining flange initially to override said outer surface of said sleeve to permit said outer surface of said sleeve to mate with the inner surface of said collar, whereby further such downward movement causes said collar to inwardly compress said sleeve toward said column and causes said retaining flange to underlie said lower edge of said sleeve, and whereby subsequent upward movement of said collar is resisted by engagement of said retaining flange on the lower edge of said sleeve.

A modular utility cart comprising:

• a plurality of support posts;
• at least one intermediate shelf mountable on said posts, said intermediate shelf including means defining a plurality of open collars each for embracing one said post, each said collar having a cross-section substantially congruent to the cross-section of one said post, an upper right tubular portion closely embracing said post, a lower tubular portion having a downwardly outwardly inclined inner surface, and a transition portion between said upper portion and said lower portion;
• a top shelf mountable in the region of the tops of said posts, said top shelf including means defining a plurality of blind tubular collars each having a downwardly outwardly inclined inner surface and an inwardly projecting retaining flange in the region of the bottom of said inner surface;
• and
• a plurality of sleeves, one for each open collar of said intermediate shelf and for each blind collar of said top shelf, each said sleeve including upper and lower edges, a right tubular inner surface closely embracing one said post and a downwardly outwardly inclined outer surface matable with said lower portion of said inner surface of said open collar and said inner surface of said blind collar;
• whereby downward movement of one said open collar about one said sleeve on an associated post causes said respective inclined inner surface of said open collar and said inclined outer surface of said sleeve to mate and inwardly compress said sleeve toward said associated post, said downward movement being limited by abutment of said top edge of said one sleeve with said transition portion of said one open collar;
• and
• whereby downward movement of one said blind collar about another said sleeve positioned in the region of the top of an associated post causes said retaining flange initially to override said outer surface of said other sleeve to permit said outer surface of said other sleeve to mate with said inner surface of said one blind collar whereby further such downward movement compresses said other sleeve toward said post and causes said retaining flange to underlie said lower edge of said sleeve, and whereby subsequent upward movement of said blind collar is resisted by engagement of said retaining flange on the lower edge of said other sleeve.