Liquid container drain device

Claim 2

A liquid container drain device comprising a drain aperture in a wall of said container, a threaded nut, a blade spring having at least one end secured to said wall and carrying said nut in spaced relation to the inner surface of said wall so that the bore of said nut is axially aligned with the drain aperture and said nut is engageable with the inner surface of said wall, a threaded plug insertable through said aperture into the bore of said nut and having a head larger than said drain aperture, and a seal element compressible between said head and the outer surface of said wall surrounding said aperture to close said aperture; said blade spring being arranged to be loaded by the insertion and unloaded by the removal of said plug, and in the unloaded condition acting to lift the nut away from said wall.

Claim 3

In combination with a liquid container having a wall and a drain aperture in said wall, closure means comprising a threaded plug having a head adapted to sealingly engage the outer surface of said wall around said aperture to close said aperture when said threaded plug extends therethrough, a nut non-rotatably mounted in spaced relation to the inner surface of said wall and having a threaded bore axially aligned with said aperture and adapted to receive said threaded plug, and spring means between said nut and the apertured portion of said wall and urging said nut and apertured portion apart, at least one of said nut and spring means being engageable with the inner surface of said wall surrounding said aperture to provide a solid backing for tightly securing said threaded plug in position to close said aperture, and removal of said plug from said aperture permitting said spring means to open a gap between said nut and spring means and said wall adjoining the inner surface of said wall through which liquid in said container may flow along said surface to reach said aperture and be drained.

Claim 4

In combination with a liquid container having a wall and a drain aperture in said wall, closure means comprising a threaded plug having a head adapted to sealingly engage the outer surface of said wall around said aperture to close said aperture when said threaded plug extends therethrough, a nut non-rotatably mounted in spaced relation to the inner surface of said wall and having a threaded bore axially aligned with said aperture and adapted to receive said threaded plug, and spring means between said nut and the apertured portion of said wall and urging said nut and apertured portion apart, at least one of said nut and spring means being engageable with the inner surface of said wall surrounding said aperture to provide a solid backing for tightly securing said threaded plug in position to close said aperture, and removal of said plug from said aperture permitting said spring means to open a gap between said nut and spring means and said wall adjoining the inner surface of said wall through which liquid in said container may flow along said surface to reach said aperture and be drained.

Claim 5

A liquid container drain device according to claim 2, in which an area of said container wall peripheral to said drain aperture has a trough-like resilient formation, whereby said area is resiliently loaded by the insertion and tightening of said plug in said nut.

Claim 6

The combination of claim 2 wherein the mounting of said nut on said wall is accomplished by a yoke secured to said wall and caging said nut so as to permit only limited axial movement thereof into and out of engagement with said wall, said spring means being separate from said yoke and said wall.

Claim 7

The combination of claim 2 wherein said spring means also comprises means for mounting said nut on said wall.

Claim 8

The combination of claim 2 wherein said spring means comprises a resilient area of said container wall peripheral to the apertured portion thereof.

Claim 9

The combination of claim 2 wherein said spring means comprises both a resilient area of said container wall peripheral to the apertured portion thereof and means for mounting said nut on said wall.