Static structures (e.g. – buildings) – Processes – Barrier construction
Reexamination Certificate
1999-02-26
2002-04-30
Safavi, Michael (Department: 3635)
Static structures (e.g., buildings)
Processes
Barrier construction
C052S220800, C052S302100, C249S207000
Reexamination Certificate
active
06378269
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The general field of the present invention relates to static structures, i.e., buildings, and to pipes and tubular conduits; more particularly to the use of a hollow form or core in the forming of a cavity or cell in a concrete slab and to providing the end of a pipe with a plug or end protector; most specifically to such a form preserving space about a hub type drain in the pouring of a concrete slab floor which includes a threaded end protector.
2. General Background
Hub type drains typically possess a drain collar seated in the open top end of the drain and secured to the same with a plurality of bolts arranged concentrically about a central threaded bore into which an adjustable strainer may be threaded. When a concrete slab floor is poured it desirable to preserve not only (a) the internal threading of the drain collar but also (b) free access to the entire drain collar for the purpose of shimming the same in order to level the drain collar after the floor is poured. It is also desirable to provide for (c) proper sloping of the finished floor proximate the drain strainer in order to achieve desired drainage characteristics and to (d) avoid a plethora of problems commonly encountered during this installation.
The final floor finish is often changed during construction, for example, and the selection of a thicker flooring will require greater depth around the drain. This will necessitate changing of the finished slope about the drain. Provision for slope in the finished floor is often wholly neglected in pouring the slab and burying of the drain during the same is also known to occur on occasion. Another problem associated with this phase of construction is the collision of equipment with the drain thereby displacing the drain from level. Another prevalent problem is that cement finishers often do not finish the slab about a drain to accommodate the finished floor.
It is considered, upon a basis of over thirty-five years experience, that the installation of hub drains during construction involving the pouring of a concrete slab floor is ineluctably and consistently plagued by the problems mentioned above. It is also considered that the only solution to these problems is chipping away concrete about the hub drain which is invariably expensive and consumptive of time.
It is noted that it is a practice of some builders to use forming lumber to block our an area about the drain leaving a rather large hole the entire depth of the slab. This practice adversely affects the integrity of the slab especially below grade. It is also noted that it is a common practice to use foam or insulation wrapped around a drain strainer threaded into the collar in order to enable adjustment of the same after the slab hardens. While preserving the ability to adjust the elevation of the drain strainer this practice neither provides access to the drain collar nor addresses the issue of sloping about the drain.
Discussion of the Prior Art
The following U.S. Patents are considered pertinent to the present invention:
U.S. Pat. No.
Inventor
Date
Title
2,202,147
Gerriets
May 28, 1940
Emplacement Former
3,421,551
Currier
Jan. 14, 1969
Destructible Article for
Reserving a Recess In
Concrete
3,800,486
Harvey
Apr. 2, 1974
Pipe Spacer
4,620,330
Izzi, Sr.
Nov. 4, 1986
Universal Plastic Plumbing
Joint
4,823,411
Nettel
Apr. 25, 1989
Cleanout Extension Adapter
4,883,590
Papp
Nov. 28, 1989
Adjustable Floor Drain
Apparatus
5,099,887
Hooper
Mar. 31, 1992
Drain Collar
5,623,971
Foernzler
Apr. 29, 1997
Drain and Cleanout Spacer
Gerriets discloses a hollow form having an outer cylindrical wall and an inner “annular wall” both connected by a top plate, all constructed of thin sheet metal or other “severable” material. The interior sleeve is preferably inclined inwardly from top to bottom to facilitate disposition within the open ends of pipes of varying diameter. A patent two years later issued to Gerriets is also noted which adds an inwardly convex shape to the interior sleeve which here fits about the pipe rather than inside the same.
Currier discloses an annular sleeve of “non-water absorbing frangible foamed plastic”, preferably polystyrene, which is slit, preferably along a diagonal, for reserving an annular space about an upright pipe, including the mouth of a pipe, during pouring of concrete or concrete. Harvey discloses a “cup-shaped” device, open at the bottom and closed at the top, possessing a cylindrical outer wall and a shorter cylindrical inner wall which possesses inwardly extending “fingers” aligned radially which can be readily broken at intervals along the axial length of each to accommodate varying outer diameters of pipes in positioning of the device about the same.
Izzi, Sr.'s 'universal plastic plumbing joint' discloses use of an outer sleeve with a smooth exterior wall intended to fit inside a pipe's open end with internal threading mating with an externally threaded internal sleeve which can be adjusted elevationally for disposition of a drain relative to the level obtained in pouring a slab of concrete, among other uses. Nettel's 'cleanout extension adaptor' discloses a similar structure using an externally threaded plug mating an internally threaded cylindrical body which possesses a “small thin, lip (extending radially outward) on the top for seating on the top of a cleanout extension”. Papp discloses, most pertinently as shown in
FIG. 5
, use of a disposable sleeve, preferably made of waxed cardboard, which fits snugly inside the open end of an internally threaded pipe and extends upward to provide a cylindrical space above the mouth during pouring of concrete and to keep the internal threading clean during the same.
Hooper discloses a “collar for a drain pipe riser . . . for maintaining an annular space about” the riser during pouring of a concrete slab possessing an external cylindrical sleeve and an internal cylindrical sleeve radially spaced apart from the outer sleeve and connected to the same by at least one set of “webs”. The 'drain and cleanout spacer' disclosed by Foernzler possesses two “cup-shaped plastic spacers joined by a flexible web”. Each spacer is simply a circular cover with a downwardly depending cylindrical outer wall dimensioned to fit over the exterior diameter of the mouth of drain strainer and a cleanout port, respectively. It is also suggested that a flag extend upwardly from one cover to provide a visual indicator.
Statement of Need
The prior art reviewed above teaches the use of frangible annular shells for the preservation of an annular space about the top of a pipe during the pouring of a concrete slab thereabout and teaches the use of threaded cylindrical members in extension of a drain plate or strainer with respect to a hub drain. The space reserved about the top of the pipe is not, however, adjustable and hence no accurate provision for sloping of the finished cement about the drain is available.
If a frangible form is deployed to reserve space about a drain hub in order to preserve access to a drain collar fitted in the same the form necessarily creates a void about the collar and the drain hub below the level of the collar. This is considered undesirable in adversely affecting the integrity of the installation in a manner similar to the adverse affect upon the integrity of the slab caused by the practice of using forming lumber about a drain noted earlier. It is considered that while it is desired to preserve access to the drain collar, in addition to preserving the internal threading of the same and the ability to adjust the elevation of the drain strainer typically engaging this threading, creating a void in the slab about the drain below the top surface of the drain collar is also undesirable for structural reasons. Another aspect of the frangible forms known in the prior art is that the form is necessarily destroyed in removal. This is considered to be wasteful at best for both economic and environmental reasons.
It is hence considered that a need therefo
Gibson Peter
Safavi Michael
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