Drain assembly with synthetic resin lock nut and coupling elements

A drain assembly for sinks, tubs, basins and similar vessels utilizes a strainer body which is of thin wall metal construction, in combination with a plastic housing subassembly, to provide significant savings in manufacturing costs. The spout portion of the stainer body has a thread of relatively coarse pitch, which preferably makes less than a full revolution thereabout and cooperates with an internally threaded metal insert, the latter being permanently affixed within an enlarged portion of the plastic housing sleeve.

BACKGROUND OF THE INVENTION 
Assemblies consisting of an internal strainer body and an external housing 
are conveniently utilized in drains of sinks, tubs, basins and like 
vessels for connection to the discharge conduit. Such assemblies are 
disclosed in the art in various forms, typical of which are the 
constructions shown in the following U.S. Pat. Nos. 2,278,566 to Schaible; 
2,961,914 to Young; 3,700,381 to Deeke; and 3,881,201 to Richards. As 
indicated by these patents, it is common practice to install the assembly 
by clamping the portion of the vessel surrounding its drain opening 
between cooperating flanges on the inner and outer members, although other 
fastening means have also been employed. For example, a screw-mounted 
supporting ring arrangement is described in Friedman U.S. Pat. No. 
3,327,326, which also shows the use of a series of nibs on the neck 
portion of the cylindrical drain body as a quick disconnect arrangement 
for locking the body in position upon the supporting ring. 
Regardless of the form of the unit, it is of course desirable to minimize 
complexity, and the cost of manufacture. Moreover, any such cost reduction 
should obviously not be accompanied by diminished quality or durability, 
and should not entail any substantial sacrifice in convenience of use or 
in ease of installation. 
Accordingly, it is the primary object of the present invention to provide a 
novel drain assembly for installation in a sink, tub, basin or like 
vessel, which can be manufactured at substantially less cost than 
comparable constructions provided heretofore. 
It is also an object of the invention to provide such an assembly in which 
no reduction in quality, durability, attractiveness, or facility of 
installation or use is entailed, as compared to similar prior art 
assemblies. 
SUMMARY OF THE DISCLOSURE 
It has now been found that the foregoing and related objects of the 
invention are readily attained in a drain assembly including a one-piece 
drain, or strainer, body of thin wall construction, and an external, 
two-piece housing. The housing is comprised of a sleeve member, integrally 
formed of a synthetic resinous material, and a ring-shaped insert firmly 
secured therewithin, the insert usually being made of a metal, such as 
aluminum. The strainer body used in the assembly is comprised of a 
generally cylindrical sidewall portion, having a circumferential flange 
portion extending outwardly about its upper end and a reduced diameter 
tubular spout portion at its lower end, the latter having integral thread 
means formed thereon for engagement with the insert of the housing. The 
sleeve member of the housing is dimensioned and configured to seat the 
strainer body, and it has flange and sidewall portions corresponding to 
those of the strainer body and a tail portion corresponding to the spout 
portion thereof. The ring-shaped insert is disposed coaxially within the 
tail portion of the sleeve member and adjacent the sidewall portion, and 
is internally threaded (preferably with a coarse thread of generally 
square cross-section) to engage the thread means of the spout portion and 
permit tightening of the housing thereupon. An externally threaded section 
is also provided on the tail portion downwardly of the location at which 
the insert is disposed, to enable connection of a drain conduit to the 
assembly. The flange portions of the strainer body and sleeve member are 
adapted to bear upon the wall of the vessel in which the assembly is 
installed, about the drain opening therein, to enable secure and effective 
mounting. 
In the preferred embodiments, the drain body will be fabricated from a 
single piece of light gauge metal sheet (such as of stainless steel or 
brass), and the thread means will extend for not more than a single 
revolution about the spout portion thereof; the thread means will normally 
extend along a helical path, and will beneficially consist of a plurality 
of discrete segments spaced from one another. The sidewall portion of the 
strainer body will usually have a downwardly tapered annular throat 
section leading to the spout portion, and the external sleeve member will 
have a corresponding throat section leading to the tail portion thereof. 
Advantageously, the housing sleeve member will be configured to provide an 
enlarged section upwardly of its externally threaded section, within which 
the ring-shaped insert will be disposed; the inside diameters of the two 
sections will desirably be substantially the same, so as to provide a 
passageway through the tail portion which is of generally uniform 
diameter. To facilitate engagement of wrenches for tightening of the 
housing upon the drain body, the sidewall of the housing will beneficially 
be formed with axial ribs, and the enlarged section of its tail portion 
will beneficially be molded with a polygonal exterior configuration.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
Turning now in detail to the appended drawings, therein illustrated is a 
drain assembly embodying the present invention and consisting of an 
internal, one-piece strainer body, generally designated by the numeral 10, 
and an external sleeve or housing subassembly, generally designated by the 
numeral 12. As can be seen, the strainer body 10 is of thin wall 
construction, and may be made by deep-drawing a sheet of metal (typically, 
0.025 inch material). The body 10 is comprised of a generally cylindrical 
sidewall portion 14 having a radially outwardly extending circumferential 
flange portion 16 at its upper end, and a reduced diameter tubular spout 
or neck portion, generally designated by the numeral 18, at its lower end; 
a conical shoulder portion 19 interconnects the sidewall portion 14 and 
the spout portion 18, providing a transition section therebetween. 
The spout portion 18 consists, in turn, of a generally cylindrical sidewall 
element 20 and a transversely extending bottom wall element 22, which is 
perforated (at locations not visible) to provide drainage apertures from 
the strainer body. The bottom wall element 22 is also formed with a 
centrally located slot 24, within which is received the pin 26 of a 
conventional crumb basket/stopper unit, generally designated by the 
numeral 28; of course, other types of baskets and means for seating them 
can be substituted if so desired. 
Four thread segments 30 are formed (such as by rolling or stamping) into 
the sidewall section 20 of the spout portion 18 at equidistantly spaced 
intervals thereabout, and are disposed on a helical path of relatively 
course pitch. In a typical case in which the spout portion has a diameter 
of approximately one and five-eights inch, four segments 30 will be 
disposed at 90.degree. intervals to provide a thread that makes less than 
a complete revolution thereabout and has a pitch of about one-eighth inch, 
and each segment will be about three-quarters inch long and one-quarter 
inch deep. 
The housing subassembly 12 includes a relatively heavy gauge plastic sleeve 
member (fabricated, for example, by injection molding an 
acrylonitrile-butadine styrene, polyvinyl chloride, or polypropylene 
resin), consisting of a cylindrical sidewall portion 32, a radially 
extending circumferential flange portion 34 at the upper end of the 
sidewall portion, and a substantially tubular tail portion, generally 
designated by the numeral 34, at its lower end, the latter being connected 
through a conical transition section 36 of the sidewall portion 32. Thus, 
the sleeve member of the housing 12 is configured to conform substantially 
to the strainer body 10, but is of somewhat larger dimensions to provide a 
well 38 for seating the body 10. As can be seen, the sidewall portion 32 
is formed with a series of axially extending ribs 40, which not only 
provide an enhanced gripping surface for tightening of the sleeve during 
assembly, but also serve to increase the overall strength and rigidity of 
the member. 
The tail portion 34 of the sleeve member 12 has an upper section 42, of 
relatively large diameter, and a reduced diameter section 44 disposed 
downwardly from the section 42 and externally threaded to engage the 
plastic slip nut or coupling 46. The latter secures the tail piece flange 
48 in a conventional and self-evident manner for connection of the drain 
pipe to the assembly, and is also formed with short axial ribs 47. 
As best seen in FIG. 2, the enlarged section 42 of the tail portion 34 has 
permanently affixed therewithin (such as by molding during the course of 
producing the sleeve member 12) a metal ring insert, generally designated 
by the numeral 50 and most fully illustrated in FIG. 4; the insert will 
usually be made of aluminum, although other metals and comparable 
materials of construction can be substituted in appropriate circumstances. 
The insert 50 has a helical internal thread 52, which is of generally 
square cross section and makes several revolutions about its inner 
surface, and it has a configured outer surface portion 54 (both serration 
and knurling being shown for purposes of illustration) in which is formed 
a pair of circumferential grooves 56. The thread 52 serves of course to 
engage the segments 30 of the strainer body spout portion 18, which 
cooperatively provide the single-revolution thread thereabout, and the 
exterior surface configuration of the insert 50 functions to anchor it 
securely and permanently within the sleeve tail portion section 42, which 
is in turn strengthened by the insert. As will be noted, the ribs 40 on 
the sidewall portion 32 of the sleeve member allow use of a spanner 
wrench, and the upper section 42 of the tail portion is formed with a 
hexagonal external configuration to facilitate gripping by common 
wrenches, for final tightening of the housing 12 upon the strainer body 
10. 
The drain assembly is installed within the opening 57, defined by the 
surrounding portion 58 of the sink, simply by inserting the strainer body 
10 therethrough until its flange portion 16 rests upon the sink surface. 
Following placement of rubber and paper washers 60, 62, respectively, 
about the sidewall portion 14, the housing 12 is attached by simply 
threading it upon the spout portion 18 of the stainer body 10, with the 
thread formations interengaged as described above. When the housing is 
tightened sufficiently upon the strainer body to ensure firm and secure 
mounting of the assembly, the drain conduit may be connected by engaging 
the coupling 46 upon the threaded section 44 to fasten the flange 48 
thereagainst. The housing provides a unit of solid, one-piece construction 
between the bottom of the sink and the drain conduit, and effectively 
prevents leakage even if, for example, an insufficient amount of compound 
is used for sealing in the sink. The crumb basket/stopper unit 28 can then 
of course be placed into the strainer body for use in the normal manner, 
to either permit or prevent flow through the assembly, depending upon the 
position of the stopper 64. 
As will be evident, the economy afforded by the invention is attributable 
primarily to the use of light gauge metal for the strainer body, instead 
of the heavy weight stampings or castings heretofore used to permit roll 
forming or cutting of threads. The present construction not only lowers 
materials costs, but it also makes the metal forming operations easier and 
thereby reduces the power demand. The spaced thread segments formed on the 
spout body are considerably easier to produce than is, for example, a 
rolled thread of several revolutions, and yet the structure provides a 
high level of strength, and secure and convenient installation in 
cooperation with the outer housing; other forms of thread means may 
however be substituted, as long as they are capable of functioning to 
afford the same advantages. Because the sleeve member is integrally formed 
as a single piece the housing subassembly is itself readily molded at 
relatively low cost, and the unique construction of the metal insert is 
especially desirable from the standpoint of producing firm securement 
within the plastic molding, as well as the desired coaction with the 
strainer body. 
Thus, it can be seen that the present invention provides a novel drain 
assembly for installation in a sink or the like, which can be manufactured 
at substantially less cost than comparable constructions provided 
heretofore. Furthermore, the unique construction used causes no reduction 
in quality, durability, attractiveness, or facility of installation or 
use, as compared to similar prior art assemblies.