Title:
Threaded sink strainer housing
United States Patent 3881201
Abstract:
A housing for securing a sink strainer body portion of a sink drain assembly in a sink drain opening is disclosed. The housing clamps an annular lip defining the sink drain opening between a flange on the sink strainer body portion and a flange on the housing. The housing has a circular thin-walled threaded portion which threadably engages a threaded spout on the sink strainer body portion so as to be positively advanced on rotation thereof to secure the sink strainer body portion in the sink drain opening. The housing expedites installation of sink drain assemblies, reduces manufacturing costs and self-centres the sink strainer body portion upon securing same in the sink drain opening.
US Patent References:
Drain fitting
Schaible - April 1942 - 2278566
Adjustable nut and shoulder unit for pipe to plate joint
Young - November 1960 - 2961914
Apparatus for securing a drain conduit to a sink
Dutcher - August 1968 - 3397902
COUPLING ASSEMBLY
Deeke - October 1972 - 3700381
Drain fitting
Schaible - April 1942 - 2278566
Adjustable nut and shoulder unit for pipe to plate joint
Young - November 1960 - 2961914
Apparatus for securing a drain conduit to a sink
Dutcher - August 1968 - 3397902
COUPLING ASSEMBLY
Deeke - October 1972 - 3700381
Application Number:
05/406037
Publication Date:
05/06/1975
Filing Date:
10/12/1973
View Patent Images:
Export Citation:
Assignee:
Premier Tool and Die Limited (Toronto, Ontario, CA)
Primary Class:
Other Classes:
285/206, 4/288
International Classes:
E03C1/22; E03C1/26
Field of Search:
4/286-292,190 210/163-166 285/159,206
Primary Examiner:
Artis, Henry K.
Assistant Examiner:
Bryant III, James E.
Claims:
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows
1. In a sink drain assembly, a housing, a tubular sink strainer body, for mounting through a sink drain opening in a sink, and having an annular flange at one end thereof which is adapted to contact the inner surface of a sink wall surrounding said opening and a threaded spout extending from the outer end of said sink strainer body, said housing being substantially tubular and of an interior dimension to permit positioning of said housing over the portion of said sink strainer body which projects exteriorly of said sink wall for securing said sink strainer body in said sink drain opening; the improvement comprising a circular thin-walled threaded portion provided at an end of said housing, said circular threaded portion being integral with said housing, the axis of said circular threaded portion being coincident with the longitudinal axis of said tubular portion, the threads on said circular thin-walled threaded portion being rolled threads and so dimensioned as to threadably engage said threaded spout to enable said housing to be positively advanced on rotation thereof to clamp said sink wall between said flange and the other end of said housing; said other end of said housing presenting an integral annular body portion having an inside diameter greater than the diameter of said sink drain opening.
2. In a sink drain assembly of claim 1, said annular body portion being a flange.
3. In a sink drain assembly of claim 1, said housing having an exterior circumferential surface with at least one flat surface on the periphery thereof to permit gripping of said housing with a wrench.
4. In a sink drain assembly of claim 2, said sink drain opening being defined by an annular lip inclined away from the interior of said sink wall; said flange on said housing being inclined at a slope which corresponds with the slipe of the inclined annular lip, said flange advancing over said inclined annular lip as said flange is brought to bear on said lip as said housing is positively advanced due to rotation thereof to urge the longitudinal axis of said sink strainer body towards the longitudinal axis of said sink drain opening.
5. In a sink drain assembly of claim 3, said housing having a neck portion from which said threaded portion extends, said at least one flat surface being formed about said neck portion.
6. In a sink drain assembly of claim 3, said exterior circumferential surface comprising a series of intersecting substantially planar surfaces which define a hexagonal body portion.
7. A sink drain assembly housing which is used to secure a sink strainer body in a sink drain opening, comprisng a tubular body portion, a circular thin-walled threaded portion at an end of said housing, an annular body portion positioned at the other end of said housing; said circular threaded portion and annular body portion being integral with said tubular body portion the axis of said circular threaded portion being coincident with the longitudinal axis of said tubular body portion, the threads on said circular thin-walled threaded portion being rolled threads, and the inside diameter of said annular body portion being greater than the diameter of said sink drain opening.
8. A sink drain assembly housing of claim 7 wherein said annular body portion is a flange inclined relative to the circumferential wall of said tubular body portion.
9. A sink drain assembly of claim 8 wherein said tubular body portion has an exterior circumferential surface comprising a series of intersecting substantially planar surface which define a hexagonal body portion.
1. In a sink drain assembly, a housing, a tubular sink strainer body, for mounting through a sink drain opening in a sink, and having an annular flange at one end thereof which is adapted to contact the inner surface of a sink wall surrounding said opening and a threaded spout extending from the outer end of said sink strainer body, said housing being substantially tubular and of an interior dimension to permit positioning of said housing over the portion of said sink strainer body which projects exteriorly of said sink wall for securing said sink strainer body in said sink drain opening; the improvement comprising a circular thin-walled threaded portion provided at an end of said housing, said circular threaded portion being integral with said housing, the axis of said circular threaded portion being coincident with the longitudinal axis of said tubular portion, the threads on said circular thin-walled threaded portion being rolled threads and so dimensioned as to threadably engage said threaded spout to enable said housing to be positively advanced on rotation thereof to clamp said sink wall between said flange and the other end of said housing; said other end of said housing presenting an integral annular body portion having an inside diameter greater than the diameter of said sink drain opening.
2. In a sink drain assembly of claim 1, said annular body portion being a flange.
3. In a sink drain assembly of claim 1, said housing having an exterior circumferential surface with at least one flat surface on the periphery thereof to permit gripping of said housing with a wrench.
4. In a sink drain assembly of claim 2, said sink drain opening being defined by an annular lip inclined away from the interior of said sink wall; said flange on said housing being inclined at a slope which corresponds with the slipe of the inclined annular lip, said flange advancing over said inclined annular lip as said flange is brought to bear on said lip as said housing is positively advanced due to rotation thereof to urge the longitudinal axis of said sink strainer body towards the longitudinal axis of said sink drain opening.
5. In a sink drain assembly of claim 3, said housing having a neck portion from which said threaded portion extends, said at least one flat surface being formed about said neck portion.
6. In a sink drain assembly of claim 3, said exterior circumferential surface comprising a series of intersecting substantially planar surfaces which define a hexagonal body portion.
7. A sink drain assembly housing which is used to secure a sink strainer body in a sink drain opening, comprisng a tubular body portion, a circular thin-walled threaded portion at an end of said housing, an annular body portion positioned at the other end of said housing; said circular threaded portion and annular body portion being integral with said tubular body portion the axis of said circular threaded portion being coincident with the longitudinal axis of said tubular body portion, the threads on said circular thin-walled threaded portion being rolled threads, and the inside diameter of said annular body portion being greater than the diameter of said sink drain opening.
8. A sink drain assembly housing of claim 7 wherein said annular body portion is a flange inclined relative to the circumferential wall of said tubular body portion.
9. A sink drain assembly of claim 8 wherein said tubular body portion has an exterior circumferential surface comprising a series of intersecting substantially planar surface which define a hexagonal body portion.
Description:
FIELD OF THE INVENTION
This invention relates to sink drain assemblies and in particular, improvements in a housing used to secure a sink drain assembly in a sink drain opening.
BACKGROUND OF THE INVENTION
Sink drain assemblies principally used in today's sinks particularly in kitchen sinks, comprise a sink strainer body portion which is mounted through a sink drain opening and is secured therein by placing a housing with a flange over the body portion which projects beyond the underside of the sink wall. The sink wall is clamped between a flange on the sink strainer body and the housing flange by threading a nut onto the threaded spout portion carried by the sink strainer body. An annular rubber gasket may be placed between the housing flange and the underside of the sink wall. A tailpiece may be threaded onto the threaded spout portion so that a drain pipe can be connected to the sink drain.
During assembly of this type of sink strainer arrangement, the housing is free to move about as the nut is threaded onto the threaded spout so that as the housing flange is brought to bear on the underside of the sink wall, difficulties are encountered in centering the sink strainer body in the sink drain opening. To further add to this problem a difficult manipulation is required in positioning the rubber gasket, housing and nut under the sink during assembly of the unit while attempting to maintain the sink strainer body within the sink drain opening. Such an assembly method may be further complicated by working in very poor lighting so that a clear view of the installation is hindered.
Most existing kitchen sinks have an annular lip which is inclined outwardly relative to the sink wall thereby making the clamping action of the sink wall between the flange of the housing and the flange of the sink strainer body insecure, because the flange of the housing is substantially horizontal as compared to the inclined lip, so that the rubber gasket is poorly clamped between the respective flanges.
The sink drain assembly according to this invention overcomes the above-noted problems by providing a housing having an integrally thin walled threaded portion provided thereon which may be adapted to thread onto the threaded spout of the sink strainer body portion such as those of the prior art. The threaded portion of the housing may extend from a reduced end thereof and, at the other end of the housing, a flange may be formed or an annular rim where the inside diameter of the rim is greater than the diameter of the sink drain opening. The sink strainer body portion may be easily secured in the sink drain opening by threading the housing onto the threaded spout to positively advance the housing flange or annular rim towards the underside of the sink wall to clamp same between the respective flanges. A rubber gasket need not be required in this installation because the housing flange may be formed so that it rotatably slides over the annular inclined lip which defines the sink drain opening, to positively clamp the sink wall between the respective flanges. The housing flange is therefore inclined upwardly at a slope which corresponds with the downward slope of the annular lip so that the outer surface of the lip mates with the inner surface of the housing flange. Self-centering of the sink strainer body is effected by using such a housing flange arrangement because as the flange rotatably slides over the annular lip, the contacting surfaces of the flange and annular lip interact so that the longitudinal axis of the housing becomes coincident with the axis of the sink drain opening thereby drawing the sink strainer body portion to the centre of the sink drain.
By using a housing according to this invention, the sink strainer body may be centered in the sink drain opening and secured therein by a simple one-step operation of threading the housing onto the threaded spout of the sink strainer body, without requiring the arranging and manipulating of an individual rubber gasket, housing and nut, thereby making installations in poor lighting situations and difficult-to-get-at drains much easier and more convenient.
A housing design according to this invention may be manufactured at comparatively reduced production costs because two pieces of material are eliminated in the assembly, namely, the rubber gasket and a threaded nut. The transportation costs of such a unit are also lowered because from a packaging aspect, the weight of the entire unit is substantially reduced.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a sink drain assembly which may be simply and more conveniently installed.
It is a further object of the invention to provide a housing for securing a sink strainer body portion in a sink drain opening which centres the sink strainer body in the sink drain opening during installation.
It is another object of the invention to provide a sink drain assembly which may be manufactured at a lower cost and transported more easily than existing comparable prior art assemblies.
It is yet another object of the invention to provide a housing having a flange so formed to rotatably slide over an inclined annular lip which defines the sink drain opening to centre the sink strainer body in the drain opening during assembly.
A BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, advantages and features of the invention are discussed in more detail hereinafter in association with the accompanying drawings in which:
FIG. 1 is a cross-sectional view of a sink having a sink drain assembly mounted therein which is characteristic of prior art devices;
FIG. 2 is an exploded view of a sink strainer body mounted through a sink drain opening and of a housing according to this invention;
FIG. 3 is a cross-sectional view of a sink having a sink drin assembly according to this invention mounted therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A sink drain assembly common to those of the prior art is shown in FIG. 1 as mounted in a sink drain opening in the sink wall 12 which is defined by an outwardly inclined annular lip 14. A tubular sink strainer body portion 16 is mounted through the sink drain opening and flange 18 formed at one end of the tubular sink strainer body retains same in the opening. To secure the sink strainer body 16 in the sink drain opening, a housing 20 is slid over the portion of the sink strainer body which projects beyond the sink wall 12 with a rubber gasket 22 placed between a flange 24 of the housing and the underside of the sink wall 12. The sink strainer body 16 has a threaded spout 26 extending from the lower end thereof. Over the threaded spout, a nut 28 is threaded to positively advance the housing 20 towards the underside of the sink wall 12, thereby clamping the sink wall between the flange 18 and the rubber gasket 22.
As shown in the structure of FIG. 1, the outwardly inclined annular lip 14 is common to most sink drain openings so that with the prior art devices, self-centering of the sink strainer body 16 as the housing 20 is brought to bear on the underside of the sink wall 12 is not effected nor is there a good clamping action between the flange 18 and the annular gasket 22 because of the difference in the inclination of flange 24 and the annular lip 14 of the sink wall 12. As a result, the task of centering the sink strainer body 16 in the sink drain opening is inefficient due to the required manual alignment of the housing with the annular gasket 22 as the nut 28 is being threaded onto spout 26 while attempting to maintain the sink strainer body 16 in the centre of the sink drain opening.
The sink drain assembly according to this invention, is shown in FIG. 2 where a sink strainer body 30 which may be identical to the sink strainer body 16 of the prior art, is mounted through a sink drain opening defined by an annular lip 32 of sink wall 34. The sink strainer body 30 has a flange 36 which rests on the upper side of the annular lip 32 to retain the sink strainer body 30 in the sink drain opening. For purposes of resisting leakage of water between the flange 36 and the upper side of the annular lip 32, a suitable waterproofing putty may be sandwiched between the opposing surfaces. The housing 38 which is used to secure the sink strainer body 30 in the sink drain opening is adapted to fit over the sink strainer body 30 and has a flange 40 at the upper end thereof. A circular thin-walled threaded portion 42 is formed at the lower end thereof, which is integral with the housing 38, and is adapted to be threaded onto threaded spout 44 of the sink strainer body 30. A hexagon nut-shaped gripping surface 46 may be provided at the restricted or neck portion of the housing 38 adjacent the threaded portion 42 so that when the unit is assembled a secure clamping of the sink wall 34 between flanges 36 and 40 is ensured.
FIG. 3 illustrates the sink drain assembly according to this invention as assembled where a suitable waterproofing putty 37 is sandwiched between flange 36 and the upper side of the annular lip 32. The housing 38 is threaded onto spout 44 to clamp the annular lip 32 between flange 36 and flange 40 so that the sink strainer body 30 is secured in the sink drain opening. As implied, the housing 38 encloses the lower portion of the sink strainer body 30 which projects exteriorly of the sink wall 34.
The flange 40 of the housing 38 has an upwardly inclined upper surface adapted to mate with the downwardly inclined lower surface of annular lip 32, both surfaces having the same relative slope. As the housing 38 is threaded onto the spout 44, the inner surface of flange 40 rotatably slides over the outer surface of the annular lip 32. The shape of the outer surface of the annular lip 32 may be considered as being that of a truncated cone so that as flange 40 of the housing 38 contacts the annular lip, the rotational movement of the housing causes the longitudinal axis of the housing to become coincident with the central axis of the sink drain opening, therefore centering the sink strainer body 30 as it is drawn into the sink drain opening. A self-centering of the sink strainer body during assembly of the unit is therefore effected.
To ensure that the sink strainer body 30 is securely mounted in the sink drain opening, a hexagon nut formation 46 is provided at the neck portion of the housing 38 to permit wrench tightening of the housing. However, it is understood that other alternative gripping surfaces may be provided on the housing 38, and for that matter, in some applications, the housing 38 may be gripped by hand and tightened sufficiently to secure the sink strainer body 30.
Although the use of a flange 40 has been illustrated as being outwardly inclined, an alternative arrangement of the upper end of the housing 38 may be used where the upper end presents an annular rim having an inside diameter greater than the diameter of the sink drain opening so that the rim contacts the underside of the annular lip 32 and due to the inclination of the lip 32, the self-centering action is realized because the inner surface of the rim rotatably slides over the outer surface of the lip.
In assembling the sink drain assembly according to this invention, the sink strainer body portion 30 is mounted through the sink drain opening and a suitable waterproofing putty is sandwiched between the flange 36 and the upper surface of the annular lip 32. The sink strainer body is then secured by simply holding it in the opening and threading the housing 38 onto the threaded spout 44 to positively advance the housing flange 40 towards the underside of the annular lip 32. Either by hand or using an appropriately sized wrench the housing can be brought to bear firmly against the lip 32 to clamp same between the flanges 36 and 40. As discussed hereinabove, this clamping action automatically self-centres the sink strainer body 30 in the sink drain opening. It is understood that the housing may be used in applications where a mating of the annular lip and the housing flange is not a good fit because sufficient clamping action may still be achieved, however, the self-centering feature could be sacrificed.
The sink drain assembly as shown in FIG. 3 may be fabricated from acceptable plumbing materials such as various stainless steel alloys and corrosion resistant counterparts. However, it is understood that various other material substitutes may be used, such as rigid plastics.
The thin-walled threaded portion 42 of housing 38 may be fabricated by rolling the thread onto the tubular portion. Similarly, the thread on the spout 44 may also be rolled according to accepted machining practices. In comparing this type of fastening arrangement for the sink strainer body 30, as compared to that used in the prior art which requires a threaded nut 28 usually formed of zinc, the cost of the housing including the threaded portion is substantially less than that required to fabricate the housing 20 and nut 28 of the prior art. Therefore not only a more convenient and simpler method of installing a sink strainer body is realized, but also a substantial reduction in production cost results. Also, the weight of the entire unit is reduced thereby cutting down on packaging and transportation costs of the sink drain assembly unit. The amount of material required in forming a housing 38 is also much less than that required in forming the housing and separate zinc nut as used in the prior art.
While various embodiments of the invention have been illustrated and described, it will be understood that variations therein may be made as will be apparent to those skilled in the art without departing from the spirit of the invention or scope of the appended claims.
This invention relates to sink drain assemblies and in particular, improvements in a housing used to secure a sink drain assembly in a sink drain opening.
BACKGROUND OF THE INVENTION
Sink drain assemblies principally used in today's sinks particularly in kitchen sinks, comprise a sink strainer body portion which is mounted through a sink drain opening and is secured therein by placing a housing with a flange over the body portion which projects beyond the underside of the sink wall. The sink wall is clamped between a flange on the sink strainer body and the housing flange by threading a nut onto the threaded spout portion carried by the sink strainer body. An annular rubber gasket may be placed between the housing flange and the underside of the sink wall. A tailpiece may be threaded onto the threaded spout portion so that a drain pipe can be connected to the sink drain.
During assembly of this type of sink strainer arrangement, the housing is free to move about as the nut is threaded onto the threaded spout so that as the housing flange is brought to bear on the underside of the sink wall, difficulties are encountered in centering the sink strainer body in the sink drain opening. To further add to this problem a difficult manipulation is required in positioning the rubber gasket, housing and nut under the sink during assembly of the unit while attempting to maintain the sink strainer body within the sink drain opening. Such an assembly method may be further complicated by working in very poor lighting so that a clear view of the installation is hindered.
Most existing kitchen sinks have an annular lip which is inclined outwardly relative to the sink wall thereby making the clamping action of the sink wall between the flange of the housing and the flange of the sink strainer body insecure, because the flange of the housing is substantially horizontal as compared to the inclined lip, so that the rubber gasket is poorly clamped between the respective flanges.
The sink drain assembly according to this invention overcomes the above-noted problems by providing a housing having an integrally thin walled threaded portion provided thereon which may be adapted to thread onto the threaded spout of the sink strainer body portion such as those of the prior art. The threaded portion of the housing may extend from a reduced end thereof and, at the other end of the housing, a flange may be formed or an annular rim where the inside diameter of the rim is greater than the diameter of the sink drain opening. The sink strainer body portion may be easily secured in the sink drain opening by threading the housing onto the threaded spout to positively advance the housing flange or annular rim towards the underside of the sink wall to clamp same between the respective flanges. A rubber gasket need not be required in this installation because the housing flange may be formed so that it rotatably slides over the annular inclined lip which defines the sink drain opening, to positively clamp the sink wall between the respective flanges. The housing flange is therefore inclined upwardly at a slope which corresponds with the downward slope of the annular lip so that the outer surface of the lip mates with the inner surface of the housing flange. Self-centering of the sink strainer body is effected by using such a housing flange arrangement because as the flange rotatably slides over the annular lip, the contacting surfaces of the flange and annular lip interact so that the longitudinal axis of the housing becomes coincident with the axis of the sink drain opening thereby drawing the sink strainer body portion to the centre of the sink drain.
By using a housing according to this invention, the sink strainer body may be centered in the sink drain opening and secured therein by a simple one-step operation of threading the housing onto the threaded spout of the sink strainer body, without requiring the arranging and manipulating of an individual rubber gasket, housing and nut, thereby making installations in poor lighting situations and difficult-to-get-at drains much easier and more convenient.
A housing design according to this invention may be manufactured at comparatively reduced production costs because two pieces of material are eliminated in the assembly, namely, the rubber gasket and a threaded nut. The transportation costs of such a unit are also lowered because from a packaging aspect, the weight of the entire unit is substantially reduced.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a sink drain assembly which may be simply and more conveniently installed.
It is a further object of the invention to provide a housing for securing a sink strainer body portion in a sink drain opening which centres the sink strainer body in the sink drain opening during installation.
It is another object of the invention to provide a sink drain assembly which may be manufactured at a lower cost and transported more easily than existing comparable prior art assemblies.
It is yet another object of the invention to provide a housing having a flange so formed to rotatably slide over an inclined annular lip which defines the sink drain opening to centre the sink strainer body in the drain opening during assembly.
A BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, advantages and features of the invention are discussed in more detail hereinafter in association with the accompanying drawings in which:
FIG. 1 is a cross-sectional view of a sink having a sink drain assembly mounted therein which is characteristic of prior art devices;
FIG. 2 is an exploded view of a sink strainer body mounted through a sink drain opening and of a housing according to this invention;
FIG. 3 is a cross-sectional view of a sink having a sink drin assembly according to this invention mounted therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A sink drain assembly common to those of the prior art is shown in FIG. 1 as mounted in a sink drain opening in the sink wall 12 which is defined by an outwardly inclined annular lip 14. A tubular sink strainer body portion 16 is mounted through the sink drain opening and flange 18 formed at one end of the tubular sink strainer body retains same in the opening. To secure the sink strainer body 16 in the sink drain opening, a housing 20 is slid over the portion of the sink strainer body which projects beyond the sink wall 12 with a rubber gasket 22 placed between a flange 24 of the housing and the underside of the sink wall 12. The sink strainer body 16 has a threaded spout 26 extending from the lower end thereof. Over the threaded spout, a nut 28 is threaded to positively advance the housing 20 towards the underside of the sink wall 12, thereby clamping the sink wall between the flange 18 and the rubber gasket 22.
As shown in the structure of FIG. 1, the outwardly inclined annular lip 14 is common to most sink drain openings so that with the prior art devices, self-centering of the sink strainer body 16 as the housing 20 is brought to bear on the underside of the sink wall 12 is not effected nor is there a good clamping action between the flange 18 and the annular gasket 22 because of the difference in the inclination of flange 24 and the annular lip 14 of the sink wall 12. As a result, the task of centering the sink strainer body 16 in the sink drain opening is inefficient due to the required manual alignment of the housing with the annular gasket 22 as the nut 28 is being threaded onto spout 26 while attempting to maintain the sink strainer body 16 in the centre of the sink drain opening.
The sink drain assembly according to this invention, is shown in FIG. 2 where a sink strainer body 30 which may be identical to the sink strainer body 16 of the prior art, is mounted through a sink drain opening defined by an annular lip 32 of sink wall 34. The sink strainer body 30 has a flange 36 which rests on the upper side of the annular lip 32 to retain the sink strainer body 30 in the sink drain opening. For purposes of resisting leakage of water between the flange 36 and the upper side of the annular lip 32, a suitable waterproofing putty may be sandwiched between the opposing surfaces. The housing 38 which is used to secure the sink strainer body 30 in the sink drain opening is adapted to fit over the sink strainer body 30 and has a flange 40 at the upper end thereof. A circular thin-walled threaded portion 42 is formed at the lower end thereof, which is integral with the housing 38, and is adapted to be threaded onto threaded spout 44 of the sink strainer body 30. A hexagon nut-shaped gripping surface 46 may be provided at the restricted or neck portion of the housing 38 adjacent the threaded portion 42 so that when the unit is assembled a secure clamping of the sink wall 34 between flanges 36 and 40 is ensured.
FIG. 3 illustrates the sink drain assembly according to this invention as assembled where a suitable waterproofing putty 37 is sandwiched between flange 36 and the upper side of the annular lip 32. The housing 38 is threaded onto spout 44 to clamp the annular lip 32 between flange 36 and flange 40 so that the sink strainer body 30 is secured in the sink drain opening. As implied, the housing 38 encloses the lower portion of the sink strainer body 30 which projects exteriorly of the sink wall 34.
The flange 40 of the housing 38 has an upwardly inclined upper surface adapted to mate with the downwardly inclined lower surface of annular lip 32, both surfaces having the same relative slope. As the housing 38 is threaded onto the spout 44, the inner surface of flange 40 rotatably slides over the outer surface of the annular lip 32. The shape of the outer surface of the annular lip 32 may be considered as being that of a truncated cone so that as flange 40 of the housing 38 contacts the annular lip, the rotational movement of the housing causes the longitudinal axis of the housing to become coincident with the central axis of the sink drain opening, therefore centering the sink strainer body 30 as it is drawn into the sink drain opening. A self-centering of the sink strainer body during assembly of the unit is therefore effected.
To ensure that the sink strainer body 30 is securely mounted in the sink drain opening, a hexagon nut formation 46 is provided at the neck portion of the housing 38 to permit wrench tightening of the housing. However, it is understood that other alternative gripping surfaces may be provided on the housing 38, and for that matter, in some applications, the housing 38 may be gripped by hand and tightened sufficiently to secure the sink strainer body 30.
Although the use of a flange 40 has been illustrated as being outwardly inclined, an alternative arrangement of the upper end of the housing 38 may be used where the upper end presents an annular rim having an inside diameter greater than the diameter of the sink drain opening so that the rim contacts the underside of the annular lip 32 and due to the inclination of the lip 32, the self-centering action is realized because the inner surface of the rim rotatably slides over the outer surface of the lip.
In assembling the sink drain assembly according to this invention, the sink strainer body portion 30 is mounted through the sink drain opening and a suitable waterproofing putty is sandwiched between the flange 36 and the upper surface of the annular lip 32. The sink strainer body is then secured by simply holding it in the opening and threading the housing 38 onto the threaded spout 44 to positively advance the housing flange 40 towards the underside of the annular lip 32. Either by hand or using an appropriately sized wrench the housing can be brought to bear firmly against the lip 32 to clamp same between the flanges 36 and 40. As discussed hereinabove, this clamping action automatically self-centres the sink strainer body 30 in the sink drain opening. It is understood that the housing may be used in applications where a mating of the annular lip and the housing flange is not a good fit because sufficient clamping action may still be achieved, however, the self-centering feature could be sacrificed.
The sink drain assembly as shown in FIG. 3 may be fabricated from acceptable plumbing materials such as various stainless steel alloys and corrosion resistant counterparts. However, it is understood that various other material substitutes may be used, such as rigid plastics.
The thin-walled threaded portion 42 of housing 38 may be fabricated by rolling the thread onto the tubular portion. Similarly, the thread on the spout 44 may also be rolled according to accepted machining practices. In comparing this type of fastening arrangement for the sink strainer body 30, as compared to that used in the prior art which requires a threaded nut 28 usually formed of zinc, the cost of the housing including the threaded portion is substantially less than that required to fabricate the housing 20 and nut 28 of the prior art. Therefore not only a more convenient and simpler method of installing a sink strainer body is realized, but also a substantial reduction in production cost results. Also, the weight of the entire unit is reduced thereby cutting down on packaging and transportation costs of the sink drain assembly unit. The amount of material required in forming a housing 38 is also much less than that required in forming the housing and separate zinc nut as used in the prior art.
While various embodiments of the invention have been illustrated and described, it will be understood that variations therein may be made as will be apparent to those skilled in the art without departing from the spirit of the invention or scope of the appended claims.