RESTRAINED PIPE JOINING SYSTEM FOR PLASTIC PIPE

• US 20090152863A1
• Filed: 12/17/2007
• Published: 06/18/2009
• Est. Priority Date: 12/17/2007
• Status: Active Grant

• Current Assignee: S & B Technical Products, Inc.
• Original Assignee: S & B Technical Products, Inc.
• Inventors: Steinbruck, Keith
• Granted Patent: US 7,845,686 B2
• Time in Patent Office: Days
• US Class Current: 285/24
• CPC Class Codes: F16L 37/148 the securing element being flexible F16L37/144 takes precedence

Abstract

A restrained pipe joining system is shown comprising male and female ends each having aligned circumferential grooves which form a canal for passage of a locking key strap. During manufacture, the female belled end is sequentially formed over a Rieber style gasket and then over a ring shaped casing member having an inner circumferential groove formed on its inner circumferential surface. Preferably, the ring shaped casing has circumferentially spaced teeth that act as a pipe stop in cooperation with an outer circumferential groove on the male spigot to index the pipes to be coupled.

Claims

1. A joining system for use in assembling a restrained joint of a first and second sections of plastic pipe, the joining system comprising:

a first section of plastic pipe having a female, belled pipe end with an end opening and having an exterior surface, an interior surface and having a circumferential recess formed in the belled pipe end adjacent the end opening on the interior surface thereof;

at least one bore communicating the exterior surface of the belled pipe end with the interior recess thereof;

a second section of plastic pipe having a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with the interior recess formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;

a ring shaped casing member installed within the circumferential recess provided in the belled end of the first section of plastic pipe, the casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the casing member is positionable so that the bore of the casing member aligns with the bore in the belled end of the first section of plastic pipe whereby the bores, in combination with the aligned recess and groove, form a canal passageway for receiving a flexible key strap inserted at least partly therethrough.

2. A joining system for use in assembling a restrained joint of a first and second sections of plastic pipe, the joining system comprising:

a first section of plastic pipe having a female, belled pipe end with an end opening and having an exterior surface, an interior surface and having a circumferential recess formed in the belled pipe end adjacent the end opening on the interior surface thereof;

at least one bore communicating the exterior surface of the belled pipe end with the interior recess thereof;

a second section of plastic pipe having a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with the interior recess formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;

a ring shaped casing member installed within the circumferential recess provided in the belled end of the first section of plastic pipe, the casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the casing member is positionable so that the bore of the casing member aligns with the bore in the belled end of the first section of plastic pipe whereby the bores, in combination with the aligned recess and groove, form a canal passageway for receiving a flexible key strap inserted at least partly therethrough;

a ring shaped sealing element installed within the circumferential recess provided in the first section of plastic pipe adjacent the ring shaped casing member, the sealing element having an inner circumferential region and an outer circumferential region, the sealing element being installed within the belled end of the female plastic pipe so that the outer circumferential region forms a seal with the interior surface of the belled end and the inner circumferential region forms a sealing surface for the exterior surface of the mating male pipe section.

3. The joining system of claim 2, wherein the sealing element is an elastomeric sealing gasket.

4. The joining system of claim 2, wherein the sealing element which is used is a Rieber style sealing gasket which has been installed on a belling mandrel and belled over in a plastic pipe bell manufacturing operation.

5. The joining system of claim 4, wherein the sealing element is installed within the circumferential recess of the belled pipe end rearwardly of the ring shaped casing member and of the end opening thereof, the sealing element having a downwardly extending sealing lip which is contacted by the exterior surface of the mating male plastic pipe during the assembly of the coupling.

6. The joining system of claim 5, wherein the ring shaped casing member has a leading edge and a trailing edge, the trailing edge being provided with a concave shaped profile which receives a leading nose portion of the sealing element to further secure the sealing element within the circumferential recess provided in the belled pipe end.

7. The joining system of claim 6, wherein the leading edge of the casing member has an externally ribbed surface which engages a mating surface on the circumferential recess provided in the belled pipe end.

8. The joining system of claim 7, wherein the casing member is also installed on a belling mandrel and belled over in a plastic pipe bell manufacturing operation.

9. The joining system of claim 8, wherein the casing member is formed of a material selected from the group consisting of metals, metal alloys, plastics and composites.

10. A joining system for joining two adjacent pipes, each of which is provided with a male, spigot pipe end and an interior surface and an exterior surface, the joining system comprising:

a pipe coupling having oppositely arranged, belled pipe ends, each of which has an end opening and having an exterior surface, an interior surface and wherein a circumferential recess is formed in each of the belled pipe ends adjacent a respective end opening thereof on the interior surface thereof;

at least one bore communicating the exterior surface coupling with each of the interior recesses of the belled pipe end;

wherein each of the male, spigot pipe sections has a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with one of the interior recesses formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;

a ring shaped casing member installed within each of the circumferential recesses provided in the coupling, each of the casing members having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the casing member is positionable so that the bore of the casing member aligns with one of the bores provided in the coupling, whereby the bores, in combination with the aligned recess and groove, form a canal passageway for receiving a flexible key strap inserted at least partly therethrough.

11. A joining system for use in assembling a restrained joint of a first and second sections of plastic pipe, the joining system comprising:

a first section of plastic pipe having a female, belled pipe end with an end opening and having an exterior surface, an interior surface and having a circumferential recess formed in the belled pipe end adjacent the end opening on the interior surface thereof,

at least one bore communicating the exterior surface of the belled pipe end with the interior recess thereof;

a second section of plastic pipe having a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with the interior recess formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;

a ring shaped casing member installed within the circumferential recess provided in the belled end of the first section of plastic pipe, the casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the casing member is positionable so that the bore of the casing member aligns with the bore in the belled end of the first section of plastic pipe whereby the bores, in combination with the aligned recess and groove, form a canal passageway for receiving a flexible key strap inserted at least partly therethrough;

an outer seal ring located on the outer circumferential surface of the ring shaped casing member and an inner seal ring located on the inner circumferential surface thereof, whereby the outer seal ring forms a seal with the interior surface of the belled end and the inner seal ring forms a sealing surface for the exterior surface of the mating male pipe section.

12. A joining system for use in assembling are strained joint of a first and second sections of plastic pipe, the joining system comprising:

a first section of plastic pipe having a female, belled pipe end with an end opening and having an exterior surface, an interior surface and having a circumferential recess formed in the belled pipe end adjacent the end opening on the interior surface thereof;

at least one bore communicating the exterior surface of the belled pipe end with the interior recess thereof;

a second section of plastic pipe having a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with the interior recess formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;

a ring shaped casing member installed within the circumferential recess provided in the belled end of the first section of plastic pipe, the casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the casing member is positionable so that the bore of the casing member aligns with the bore in the belled end of the first section of plastic pipe whereby the bores, in combination with the aligned recess and groove, form a canal passageway for receiving a flexible key strap inserted at least partly therethrough;

wherein the circumferential recess which is provided in the belled pipe end has a leading wall region, a trailing wall region and a bottom wall, and wherein a series of circumferentially spaced teeth are provided on the inner circumferential surface of the casing member which are alignable with a second circumferential groove provided on the exterior surface of the mating male spigot pipe end for receiving and engaging the casing member teeth, the location of the second circumferential groove and the casing member teeth being indexed a calculated distance from the trailing wall region of the circumferential recess.

13. The joining system of claim 12, wherein the engagement of the casing member teeth in the second circumferential groove provided on the exterior surface of the mating spigot pipe end assures the correct alignment of the circumferential recess and bore of the belled pipe end, and the bore in the casing member and the first groove in the mating male pipe member for proper receipt of the flexible key strap.

14. A method of manufacturing a joining system for use in assembling a restrained joint of two sections of plastic pipe, the method comprising the steps of:

providing a forming mandrel having an inner end and an outer end and having an outer working surface;

locating a ring shaped casing member at a first circumferential position on the outer working surface of the mandrel, the casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface of the casing member to communicate with the groove which is provided on the inner circumferential surface thereof,

forming a belled pipe end about the ring shaped casing member first heating a female end of the plastic pipe and then forcing the heated female pipe end over the working surface of the mandrel and over the casing member, whereby the heated female end of the plastic pipe flows over the casing member to form a retention groove for the casing member; and

thereafter cooling the female pipe to form a belled pipe end followed by retracting the belled pipe end with its retained casing member from the working surface of the mandrel; and

wherein the casing member is positioned within groove formed in the belled pipe end so that the bore in the casing member aligns with a bore provided in the belled pipe end, whereby the aligned bores form a passageway for receiving a flexible key strap inserted at least partly therethrough.

15. The method of claim 14, wherein a companion ring shaped seal element is positioned at a second circumferential position on the outer working surface of the mandrel, and wherein the belled pipe end is formed about the ring shaped casing member and the companion seal element by first heating a female end of the plastic pipe and then forcing the heated female pipe end over the working surface of the mandrel and over the casing member and seal element, whereby the heated female end of the plastic pipe flows over the casing member and seal element to form a retention groove for the casing member;

and thereafter cooling the female pipe to form a belled pipe end followed by retracting the belled pipe end with its retained casing member and seal element from the working surface of the mandrel.

16. The method of claim 15, wherein the casing member has a series of circumferentially spaced teeth on the inner circumferential surface thereof and wherein the belling mandrel is provided with a series of circumferentially spaced axial grooves in the outer surface thereof at a selected location to accommodate the circumferentially spaced teeth of the ring shaped casing member during belling manufacturing operations.