Plumbing sleeve

A pipe coupling is described suitable for joining together drainage, or other, plastic piping through a poured concrete layer, typically a floor. The coupling permits precise location of fittings, such as a toilet flange, after the concrete has been poured and set.

BACKGROUND OF THE INVENTION 
This invention is concerned with a plumbing sleeve suitable for connecting 
to a toilet, or other relatively fixed installation, placed on a concrete 
floor. 
In many buildings and similar structures concrete floors are used to which 
various plumbing fixtures, particularly toilets, have to be attached. 
Generally speaking, a piping connection will extend substantially 
vertically downwardly through the floor, thus connecting the toilet or 
other fixture above it to a sanitary or sewer main below it. It is usual 
practice to place the piping connection in position before the concrete 
comprising the floor is poured and allowed to set into place around it, 
inherently securing the piping connection in place. However, once the 
concrete has been poured and has set, any adjustment to the piping 
connection becomes impossible. This is particularly important for a 
toilet, where a sanitary connection is absolutely necessary. Once any 
flange or cap has been placed, and the cement set, it is effectively 
immovable. On the other hand, it is extremely difficult to pour concrete 
for a floor to an exact and predetermined height. In other words, when 
placing such a piping connection it is almost impossible to predetermine 
with sufficient accuracy to guarantee the required sanitary joint exactly 
where that joint is going to be. 
There are two types of concrete floor or other surface which have to be 
considered: those where there is a free space below, such as an 
intermediate floor in a high-rise building, and those where there is no 
free space below, such as a slab placed on grade. Floors with a space 
below them are poured, generally, onto some form of supported wooden 
shuttering. Various proposals have been made to facilitate placement of a 
vertical sanitary, drain or sewer pipe in such floors. Morell, in Canadian 
Patent 680,724 describes a pipe sleeve structure which is essentially a 
short tube having a radially outwardly extending flange at one end. The 
sleeve is of flexible plastic, the flange has a plurality of centering 
openings and the tube has a length less than the thickness of the floor to 
be laid. In use, the sleeve is nailed to the wood shuttering, and thus 
appears to serve primarily to locate the position of the desired hole. A 
conventional pipe is placed into the short tube. Morell is silent as to 
what happens to the sleeve when the shuttering (to which it is nailed) is 
removed. A similar device is described by Hagedorn in Canadian Patent 
767,536. 
A more complex arrangement is described by Cornwall in Canadian Patent 
1,162,21. In this coupling, a three part system is used comprising a 
coupling part which is at least temporarily supported by the shuttering. 
Conventional piping is inserted from both above and below, to the top end 
of which is attached a suitable fitting, for example to attach a toilet 
thereto. Again, the coupling is nailed in place onto the shuttering, and 
the upper fitting placed thereon before the floor is poured. 
Thus none of these devices appear to address the problem of floor thickness 
variation, nor do they appear to be applicable to a slab which is not 
poured onto shuttering. It is thus apparent that a need exists for a 
simple pipe sleeve unit which can be used in concrete floors which are not 
poured onto shuttering. Advantageously such a sleeve should also be 
amenable to use in situations where shuttering is used. 
SUMMARY OF THE INVENTION 
Thus this invention provides a plastic coupling for plastic pipes which is 
adapted to be embedded in concrete or the like. The adapter consists of a 
substantially cylindrical tube, having substantially concentric inside and 
outside walls. One end of the adapter has a larger internal diameter than 
the other, the two ends being joined together by an intermediate radial 
flange. The narrower end of the coupling includes an internal annular rib, 
having two spaced shoulders, which separates the narrower end into two 
parts. These two parts are sized to mate with the outside diameters of the 
two plastic pipes to be coupled by the coupling. The shoulders of the 
internal annular rib have a height such that the internal diameter of the 
rib is substantially the same as the internal diameter of the smaller of 
the plastic pipes being coupled. The wider end of the coupling has an 
internal diameter greater than the outside diameter of the pipe which 
passes through it to enter into the ends of the narrower part of the 
coupling adjacent the internal flange.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring first to FIG. 1, the coupling shown generally at 1 which is 
generally cylindrical in shape, consists essentially of three parts: a 
narrower first tube part 2, an intermediate radial flange 3, and a wider 
second tube part 4. As can be seen from the cross-section in the figure, 
the second tube part 4 has a plain internal wall for its full length down 
to the inside upper face 5 of the flange 3. The bore of the narrower first 
tube part 2 is divided into a first wall 6 adjacent to, and as shown 
incorporating the inside face of, the radial flange 3, an internal rib 7, 
and a second wall 8. The internal rib 7 as shown has a square 
cross-section. Its height, as will be seen more fully below with respect 
to FIG. 2, corresponds to the wall thickness of the pipes to be inserted 
into the narrower tube, from each end thereof. 
In FIG. 2, the coupling is shown installed and attached to the base of a 
toilet, through an on-grade concrete floor. The method of installation is 
as follows. First, an underground sanitary sewer connection pipe 9 is 
placed in the subsoil 20 in the desired location. The sleeve shown 
generally at 1 is then placed over and cemented to the pipe end 9, with 
the cut end of the pipe mating to, and cemented to, the second wall 8 of 
the narrower portion, 2, of the coupling. The cut end, as shown, 
substantially abuts the internal rib 7. At this stage, the wider tube 4, 
of the coupling 1 will protrude beyond the desired final surface level 41 
of the layer of concrete 40. After the coupling is placed, any desired 
gravel layer, as at 30, is placed, followed by a water impervious membrane 
if required, as at 31 (which will also usually be sealed with grout or 
adhesive to the coupling) and by the concrete 40, which is finished by 
trowelling or the like to provide a final surface 41. In many such 
installations, a layer of ceramic tile will be laid onto the concrete: in 
that case 41 will represent the final top surface of the tiles. In other 
words, a final use surface 41 is provided on top of the concrete 40. At 
this stage, the extra length of the coupling (shown ghosted at 4A) will 
still protrude beyond the surface 41. 
The next step is to trim back the excess protruding length of the upper 
part of the coupling, that is the part ghosted at 4A, to be flush with the 
final surface 41 of the concrete floor. A length of standard pipe 10 is 
then mated into, and cemented to, the first wall section 6 in the smaller 
tube 2. To the top of pipe 10 is attached a standard toilet flange 11, by 
cementing. The toilet, the base of which is shown generally at 12, is then 
located on the floor and anchored by means of conventional bolts and the 
like, which will include a suitable sealed connection (not shown) to the 
toilet flange 11. 
It can thus be seen that the sleeve of this invention by placing the 
necessary pipe joint well below floor level permits the insertion between 
the above-floor unit for which drainage is required and the pipe coupling 
of a short length of normal pipe. It is a straightforward matter to cut 
this pipe to exactly the required length after the concrete has been 
poured, has set, and (where relevant) has had a final surface applied, for 
example ceramic tiles. 
Although described above in terms of attaching a toilet to a sub-floor and 
below grade sanitary pipe of the same diameter as the toilet pipe, this 
invention is not limited to that situation. In many applications the 
outside diameter B of the subsoil pipe will differ from the outside 
diameter A of the conventional house pipe: the subsoil pipe may well be a 
thin wall polythene pipe, and the house pipe a thick-wall ABS pipe; 
further the subsoil pipe may be of a different nominal internal diameter 
to the conventional pipe, which again will change the outside diameter. 
The coupling can also be used in situations where the concrete is to be 
laid onto shuttering. In that case, the taper in the coupling 13 will 
serve to centralize the coupling in the aperture provided in the 
shuttering. It can also be used for items other than a toilet (for 
example, a floor drain), and can also be used in positions other than 
substantially vertical.