PIPE CONNECTIONS

Abstract: A method of and means for making pipe-to-pipe connections in which the pipes (10) are provided with socket ends (12) and with spigot ends (14) for mating with the socket ends (12) of pipes to be connected therewith. Each socket end (12) being provided with an annular portion (16) of increased diameter. The socket ends (12) are of malleable material capable of being crimped around a spigot end (14) of the mated pipe (10). An annular element (18) is provided within the pipe con­ nection. The element (18) is an olive desirably positioned in the inside of the annular portion (16).

Description: This invention relates to pipe connections of a type not requiring the use of solder or other flowable sealant and not requiring the use of flux. Heretofore, there have been two types of pipe connections, known as capilliary joints and as compression joints. The capilliary joint is made by heating a close fitting pipe connection between two pipes, the connection containing an internal ring of solder, whereby the solder, which is a lead alloy, melts and flows between the wall interstices thereafter cooling to solidify and make a fluid-tight connection. The forming of this type of connection has disadvantages in that it requires heat, normally in the form of a blow lamp, to melt the solder. This operation is a fire hazard. Also, the solder since it contains lead has health hazards. Further, to make the connection, it is necessary to use flux which is corrosive to metal and damaging to the hands of the user, and if the flux is not fully used up during the heating process, it remains in the connection and, like the solder, has health hazards. A pre-requisite for the success of this type of connection is that the wall surfaces at the interstices are to be clean, and no water has to be flowing in the pipe. The compression joint consists of a ring or olive of brass or copper being compressed between a threaded part of a connection housing and a compression nut which shrouds the threaded part of the housing. Under compression the olive which can have a camfered cross-section, deforms to bite into the pipe so that a fluid-tight connection is formed. This connection while it has not the disadvantages of the capilliary joint does have its own disadvantages which have in fact caused the capilliary joint, despite its disadvantages, to become the more popular and widely used. The disadvantages of the compression joint are ones of costs to produce and labour costs to fit, apart from the fact that it is bulkier and therefore more noticable than the capilliary joint. Also, there is the problem that, at least for domestic requirements, the pipes to be aesthetically pleasing have to be fitted near to walls or in corners. This means that there is limited access for a spanner or like tool to turn the nuts onto the threaded parts of the housings, and therefore it takes longer to tighten and form each connection. GB-A-511 527 disclose a coupling device for coupling together two pipes, the device comprising a ductile metal sleeve having two lengthwise spaced, outward projecting swages internally of which rubber rings are fitted. With two pipes located in the sleeve and abutting in the sleeve between the two swages, the swages are deformed or compressed against the pipe ends to form a completed joint. DE-A-1 945 362 discloses a connection comprising a metal sleeve for coupling together two pipes. The sleeve surrounds each pipe end with gripping rings there between. The sleeve is crimped on each pipe and the gripping ring is pressed into the respective pipe. An object of the present invention is to provide pipe connections which obviate or mitigate the aforesaid disadvantages. Accordingly, a first aspect of the present invention is a pipe-to-pipe connection between a first pipe and a second pipe comprising a first pipe having at an end thereof a socket of increased diameter and of a malleable material over at least part of its thickness, an annulus having an outer diameter fitting to an inner diameter of said pipe socket end, and an inner diameter to accommodate a spigot end of a second pipe inserted therewithin characterised in that said annulus is of a malleable material and is formed on an inside surface at a peripheral edge thereof with at least one gripping element, said first pipe malleable socket end and said malleable annulus edge are crimpable to form a sealing contact with said spigot end of said second pipe inserted into said annulus within said first pipe in an assembled state, and said annulus peripheral edge is sloped to taper toward the inside surface thereof and is formed with a plurality of cuts therein so as to reduce force necessary to crimp said annulus edge. The annulus is preferably positioned within said first pipe socket end and retained therein by a crimped portion of said socket end. The annulus is desirably affixed to said first pipe socket end. Preferably also, the annulus is formed of metal. Preferably further, a ring of compressable material is positioned adjacent to the annulus within the socket end in the assembled state. Also accordingly, a second aspect of the present invention is a method of connecting two pipes together in end-to-end relationship comprising the steps of swaging an end of a first pipe composed of malleable material over at least part of its thickness to form a socket end of increased diameter, forming an annulus having an outer diameter fitting to an inner diameter of said first pipe swaged socket end and an inner diameter to fit a spigot end of a second pipe, assembling said first pipe, said annulus and said second pipe so that a spigot end of said second pipe is fitted into said annulus and positioned within said first pipe socket end characterised in that the annulus is of a malleable material and formed to have a peripheral edge with a gripping element at an inside surface thereof, said annulus peripheral edge being sloped to taper toward the inside surface thereof and being formed with a plurality of cuts therein, and crimping said socket end of said first pipe around said annulus and second pipe to form sealing contact, force of said crimping also serving to crimp said annulus peripheral edge to form sealing contact with said second pipe. Preferably, the assembling step comprises first assembling said annulus to said first pipe by inserting the annulus into said socket end and crimping a portion of said socket end so as to retain said annulus therein, and inserting said second pipe into said annulus within said first pipe socket end prior to performing said final crimping step. Further accordingly, a third aspect of the present invention is a pipe assembly formed of a plurality of pipe-to-pipe connections as recited above in the next seven preceding paragraphs, wherein at least one first pipe of said assembly is formed with a socket end at each end. Embodiments of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:- Fig. 1 is a perspective view of a pipe connection according to a first embodiment of the present invention between a socket end and a spigot end of two mated pipes, part of the socket end being cut away for clarity; Fig. 2 is a plan view of the pipe connections shown in Fig. 1; Fig. 3 is a cross-sectional view of a pipe connection according to a second embodiment, showing three pipes connected together by a connector; Fig. 4 is cross-sectional view of a connector to a larger scale showing both ends formed as socket ends with one partly crimped to hold an annular element in position, the element not being shown; Fig. 5 is a detail of one socket end shown in Fig. 4 with part cut-away to reveal an annular element and a compressible ring in position; and Fig. 6 is a cross-sectional view of an annular element to a larger scale. Referring to Figs. 1 and 2 of the drawings, in a first embodiment a pipe 10 of malleable material is provided with a socket end 12 and a spigot end 14, the socket end 12 being swaged to receive the spigot end 14 of a mating pipe in end-to-end relationship. The term 'swaged' is used herein and in the claims to include the process of increasing in diameter an annular portion of an end of a pipe or pipe connector by mechanical means or by the increase being formed as part of a casting. The socket end 12 has a portion 16 of increased diameter and the spigot end 14 has a complementary shaped portion 18. The portion 16 of increased diameter is of annular convex section and the outer surface of portion 18 is of annular complementary convex section. The portion 18 is formed of an annulus in the form of an olive fitted over the spigot end 14 of each pipe 10. In use, a pipe assembly is formed from a plurality of pipes 10 fitted in end-to-end relationship with the portion 18 of each spigot end 14 seating inside the portion 16 of the socket end 12 of a mated pipe. The outer end of the portion 16 of each socket end is then crimped around said portion 18 of each metal spigot end 14 to form a fluid-tight connection. Referring to Figs. 3, 4 and 5, a second embodiment is shown in which a pipe connector 40 of malleable material is used to connect three pipes 10. The pipe connector 40 as shown in Fig. 3 is a T-piece, but could be a straight piece as shown in Figs. 4 and 5, or a curve (or corner or knuckle) piece to connect two lengths of pipe. The connector 40 has three ends, each fashioned as a socket end 12. Each socket end 12 is provided with an annular portion 16 of increased diameter and internally concave. The spigot end 14 of each pipe 10 has a corresponding annular portion of increased diameter and externally complementary convex to mate with a portion 16. In use, the pipe assembly is fitted together using one T-piece connector 40 and the three pipes 10 with each end to be mated fitted with an annular or olive 18. After being mated, the connections are crimped to form fluid-tight connections. In a preferred modification of this second embodiment, the connectors are provided with an annulus 18 of metal already fitted internally into each annular portion 16 of a socket end. In this modification, each end of pipe length 10 can be fitted into a socket end of the connector 40 without first having to have an annulus fitted. The outer end of the portion 16 of each socket end is partially crimped circumferentially or radially or rolled to hold the annulus 18 therein while not impeding entry of a spigot end of a pipe length 10. Alternatively, the annulus 18 is otherwise secured in the annular portion 16, for example by adhesion. In this modification, the pipe lengths may be of rigid plastics material and can be of flexible plastics material provided that liner collars are fitted into the spigot ends to lend support during crimping and to maintain the crimped position thereafter. In each of the above embodiments, a compressible ring 42 can be provided to seat between the portions 16, 18 when fitted together. The ring 42, which is a rubber O-ring is shown in Figs. 1 and 2 seated in a groove provided in the outer surface of annular portion 18. The ring 42 need not be so positioned and can be positioned in front of (as shown in Fig. 5) or leading the portion 18 in the direction of the pipe being mated or at the rear or trailing the portion 18. Two rings 42 can be provided one at the front edge and one at the trailing edge of the annular portion 18. Also in the alternative, the ring 42 can be seated in the portion 16. The ring 42 can be of a natural or synthetic rubber material, and may be of a shape other than an O-ring. Referring to Fig. 6, the olive 18 of metal is provided with a series of cuts 50 which are made in one edge thereof. The cuts 50 are V-shaped and converge into a slot shape towards the opposite edge as shown. The outer surface 52 of the edge in which the cuts 50 are provided is pared towards the inner surface as shown. The number and dimensions of the cuts 50 in the series may vary from, for example three to eight, four being cut in the olive shown in Fig. 6. The inside surface 54 of the olive is provided with one or more peripheral gripping elements 56 (one only being shown). Each element 56 extends inwardly proud of the inside surface 54 and has a sloped face 58 and another face 60. The cuts 50 impinge into and through the elements 56 as shown. In use, the annulus 18 above-described is advantageous since it requires a minimum amount of effort to crimp the socket end of pipe connector compared to a non-cut annulus. The annulus can be located in the portion 16 with the cuts 50 facing towards or away from the open socket end. The olive 18 may be formed from a pre-cut length of strip material having a formation on one side to serve as a gripping element and being provided with cuts above described extending from one side towards the other side. The socket ends of a connector 40 may be of the same or of different diameters. Any suitable means for crimping the outer end of portion 16 of a socket end 12 can be used and desirably can be of the type described and shown in my UK Patent Application No. 8815643.5. In a first modification, as shown in Fig. 4, a peripheral groove 62 or a series of dimples may be provided around the connector 40 to serve as an internal limit against which the spigot ends of pipe lengths 10 can abut. In another modification, the pipes can be two tubular elements to be fitted in end-to-end relationship, the tubular elements not being intended to convey any fluid. In another modification, the gripping elements may not extend in a continuous peripheral manner around the inside of the olive but may be in one or more radial parts peripherally around the inside of the olive.

Claims: Pipe-to-pipe connection between a first pipe (10) and a second pipe (10) comprising a first pipe (10) having at an end thereof a socket of increased diameter and of a malleable material over at least part of its thickness, an annulus (18) having an outer diameter fitting to an inner diameter of said pipe socket end (12), and an inner diameter to accommodate a spigot end (14) of a second pipe inserted therewithin characterised in that said annulus (18) is of a malleable material and is formed on an inside surface at a peripheral edge thereof with at least one gripping element (56), said first pipe malleable socket end (12) and said malleable annulus edge are crimpable to form a sealing contact with said spigot end (14) of said second pipe inserted into said annulus (18) within said first pipe (10) in an assembled state, and said annulus peripheral edge is sloped to taper toward the inside surface thereof and is formed with a plurality of cuts (50) therein so as to reduce force necessary to crimp said annulus edge. The connection as claimed in claim 1, characterised in that said annulus (18) is positioned within said first pipe socket end (12) and retained therein by a crimped portion of said socket end (12). The connection as claimed in claim 1, characterised in that said annulus (18) is affixed to said first pipe socket end (14). The connection as claimed in claim 1, characterised in that said annulus (18) is formed of metal. The connection as claimed in any one of the preceding claims, characterised in that a ring (42) of compressible material is postioned adjacent to said annulus (18) within said socket end (12) in the assembled state. A method of connecting two pipes together in end-to-end relationship comprising the steps of swaging an end of a first pipe (10) composed of malleable material over at least part of its thickness to form a socket end (12) of increased diameter, forming an annulus (18) having an outer diameter fitting to an inner diameter of said first pipe swaged socket end (12) and an inner diameter to fit a spigot end (14) of a second pipe (10), assembling said first pipe (10), said annulus (18) and said second pipe (10) so that a spigot end (14) of said second pipe (10) is fitted into said annulus (18) and positioned within said first pipe socket end (12) characterised in that the annulus (18) is of a malleable material and formed to have a peripheral edge with a gripping element (56) at an inside surface thereof said annulus peripheral edge being sloped to taper toward the inside surface thereof and being formed with a plurality of cuts (50) therein, and crimping said socket end (12) of said first pipe (10) around said annulus (18) and second pipe (10) to form sealing contact, force of said crimping also serving to crimp said annulus peripheral edge to form sealing contact with said second pipe (10). The method as claimed in claim 6, characterised in that the assembling step comprises first assembling said annulus (18) to said first pipe (10) by inserting the annulus (18) into said socket end (12) and crimping a portion of said socket end (12) so as to retain said annulus (18) therein, and inserting said second pipe (10) into said annulus (18) within said first pipe socket end (12) prior to performing said final crimping step. The method as claimed in claim 6, characterised in that the assembling step comprises first fitting said annulus (18) to the spigot end (14) of said second pipe (10), and inserting said spigot end (14) and said annulus (18) into said first pipe socket end (12) prior to performing said crimping step. The method as claimed in claim 6, 7 or 8, characterised in that comprising the further step of providing a ring (42) of compressible material adjacent to said annulus (18) within said socket end (12) prior to said crimping step. The connection as claimed in any one of claims 1 to 5, characterised in that said first pipe (10) is a straight pipe having a socket end (12) at each end. The connection as claimed in any one of claims 1 to 5, characterised in that said first pipe (10) is a curved pipe having a socket end (12) at each end. The connection as claimed in any one of claims 1 to 5, characterised in that said first pipe (10) is a T-piece having a socket end (12) at each end. A pipe assembly formed of a plurality of pipe-to-pipe connections as claimed in any one of claims 1 to 5, characterised in that each pipe (10) includes a spigo end (14) or a socket end (12). A pipe assembly formed by a plurality of pipe-to-pipe connections as claimed in any one of claims 1 to 5, characterised in that at least one said first pipe (10) of said assembly is formed with a socket end (12) at each end. A pipe assembly as claimed in claim 14, characterised in that said at least one first pipe (10) is a T-piece. The connection as claimed in claim 5, characterised in that the ring (42) is seated at or adjacent to the outer end of the annulus (18). The connection as claimed in Claim 5, characterised in that the ring (42) is seated at or adjacent to the inner end of the annulus (18). The connection as claimed in claim 5, characterised in that a ring (42) is provided at each of the outer and inner ends of the annulus (18). The connection as claimed in any one of claims 1 to 5, characterised in that the cuts (50) are made inwardly from one edge of the annulus (18). The connection as claimed in claim 19, characterised in that the cuts (50) extend towards the opposite edge of the annulus (18). The connection as claimed in claim 20, characterised in that the one or more gripping elements (56) each extend inwardly peripherally proud of the inside surface of the annulus (18). The connection as claimed in claim 21, characterised in that each gripping element (56) has a sloped face (58) and another face (60). The connection as claimed in claim 21 or 22, characterised in that the cuts (50) impinge into and through the or at least one of the peripheral gripping elements (56). The connection as claimed in any one of claims 1 to 5, or 10 to 23, characterised in that the annulus (18) is formed from a pre-cut length of a strip of material to be formed into the annulus (18) shape prior to being positioned in the annular portion of a respective socket end (12).

Inventors: IRWIN, WILLIAM JAMES
Applicants: IRWIN, WILLIAM JAMES
Application year: 1988
Main classification: F16L13
IPC codes: F16L13