Drain fitting for waterbed mattresses

A waterbed structure including a mattress (M) fabricated of thin flexible water-impervious sheet material and including horizontal top and bottom walls (10 and 11) with upper and lower surfaces and vertical side walls 12 with inner and outer surfaces about and extending between perimeter edge portions of the top and bottom walls (10 and 11);

• a frame (F) including a horizontal platform (P) below the lower surface of and supporting the bottom wall (11) and vertical boards (B) positioned outward of the outer surfaces of and supporting the side walls (12);
• a volume of water within the mattress normally supporting the top wall (10) on a horizontal plane spaced above the bottom wall (11) and that is close to the horizontal top plane of the frame (F) defined by upper edges of the boards (B);
• a drain fitting connected with the mattress (M) to drain water therefrom through a drain opening (22) in a lower edge portion of a side wall (12) immediately above the upper surface of the bottom wall (11), said fitting (D) includes an elongate flexible normally substantially horizontally disposed drain tube (23) with inner and outer ends extending parallel with said side wall (12) between said side wall (12) and its related board (B), a tubular neck (24) with inner and outer ends and angularly related to and connected with and between the inner end of the tube (23) and the side wall (12) at the drain opening therein, said tube (23) is selectively manually bendable from its normal horizontal position to an upturned position where its outer end is disposed substantially vertically upwardly and is accessible at the top planes of the mattress (M) and frame (F), coupling means (T) at the outer end of the tube (23) to selectively sealingly couple the outer end of the tube (23) with a closure part (C) and with the inner end of an elongate drain hose (H), and an elongate horizontally disposed spacer part (S') with an outer end at the inner end of the neck (24) and an outer end portion projecting inwardly from the neck (24) through the drain opening (22) and into the mattress (M) across the upper surface of the bottom wall (11) thereof and defining a central longitudinal flow passage communicating with the neck (24) and having radial openings throughout its longitudinal extent and opening into the central flow passage and into the interior of the mattress.