Floor drain with a hidden thread clamp.

Abstract

A thinset floor drain comprises a floor-mounted flanged pipe piece presenting a hidden thread inside a deep ring-shaped groove formed into the upper surface of the flange, and a second flanged pipe piece with an internal thread. The first piece is mounted pipe down in a perforation in the subfloor of a wet room with screws. The second piece is threaded from above into the hidden thread to form a clamp for a perforated sheet of membrane placed interstitially to the two flanges drawn together by the engagement of the thread mate, to achieve a watertight connection between the drain and the membrane. Because the thread mate sits largely below the subfloor tow which the floor drain is mounted, the upper surface of a grate assembly threaded into the mounted and clamped drain will present a low profile above the surface of the subfloor.

1 . A membrane clamp consisting of two pieces, a flanged pipe piece that is fastened to the subfloor such that the pipe downwardly penetrates a hole in the subfloor and the flange presents upward, and an upper flanged pipe piece, wherein:
 the engagement of a thread internal to the pipe feature of the upper piece into a hidden thread formed on the inner side of a deep circular groove concentric to the central drainage perforation in the upper surface of the flange of the lower mounted piece, serves to clamp an interstitial membrane for the waterproof attachment of the drain to the membrane necessary for a watertight wet room floor.   
     
     
         2 . A floor drain equipped with a membrane clamp as claimed in  claim 1  wherein:
 a grate subassembly can be threaded to an appropriate depth into the thread internal to the pipe of the upper flanged pipe to provide a grate surface contiguous with the upper surface of the tiles, owing to all threadmates being located substantially below the surface of the subfloor. 
 
     
     
         3 . A floor drain equipped with a membrane clamp as claimed in  claim 1  wherein:
 weeping features in the upper flange of the upper flanged pipe piece allow for weeping drainage of wet room water draining through tile grout and along the membrane surface sloped toward the drain into the central drainage perforation, avoiding the need for provision of gravel for weeping.