Pipe fitting and associated methods and apparatus

A pipe fitting includes a polymeric body molded into and fixedly connected to a metallic body, so that the metallic body extends around the polymeric body. The polymeric body extends around and is contiguous with a passageway of the pipe fitting, and at least partially defines a first opening of the passageway that is for being mated to a polymeric pipe. The metallic body extends around and is contiguous with the passageway, and at least partially defines a second opening of the passageway that is for being mated to a metallic pipe.

BACKGROUND OF THE INVENTION

One aspect of the present invention relates to a pipe fitting for connecting between dissimilar pipes, or the like, and, more particularly, for connecting between metallic and polymeric pipes, or the like.

It is common for substances to flow between metallic and polymeric pipes that are connected by a pipe fitting. As a more specific example, water is often supplied from an upstream metallic pipe to a downstream polymeric pipe that is the inlet of a plumbing fixture or appliance, such as a faucet or the like. It is critical for this type of pipe fitting to remain watertight, often for very many years. Nonetheless, it is common for some of these pipe fittings to occasionally fail, since they are typically exposed to many cycles of stress caused by variations in the pressure and/or temperature of the water being supplied.

A known pipe fitting for connecting between metallic and polymeric pipes is formed by separately manufacturing generally cylindrical polymeric and metallic bodies, and then connecting the bodies to one another. The polymeric body is inserted into an annular opening of the metallic body, and then the annular edge of the opening is bent inward (e.g., crimped) to hold the polymeric body in the metallic body. For this known pipe fitting, the polymeric body extends around a passageway of the pipe fitting and defines a first opening to the passageway, and the first opening is for being mated to the polymeric pipe. In addition, the metallic body extends around the polymeric body and defines a second opening to the passageway, and the second opening is for being mated to the metallic pipe. These pipe fittings have been known to fail at the crimp, because the crimping can weaken the metallic body.

Accordingly, there is a need in the industry for improved pipe fittings for connecting between metallic and polymeric pipes.

BRIEF SUMMARY OF SOME ASPECTS OF THE INVENTION

Aspects of the present invention include the provision of an improved pipe fitting that is capable of connecting between pieces of plumbing such as, but not limited to, metallic and polymeric pipes, and the provision of methods and apparatus for making pipe fittings.

In accordance with one aspect of the present invention, a composite pipe fitting includes a polymeric body that is molded to and fixedly connected to a metallic body. It is preferred for at least a portion of the polymeric body to be molded into the metallic body such that the metallic body extends around the polymeric body. The polymeric body extends around and is contiguous with a passageway of the pipe fitting. The polymeric body also at least partially defines a forward opening of the passageway that is for being mated to a piece of plumbing such as, but not limited to, a polymeric pipe. The metallic body at least partially defines a rearward opening of the passageway that is for being mated to a piece of plumbing such as, but not limited to, a metallic pipe. It is preferred the metallic body to extend around and be contiguous with the passageway.

In accordance with one aspect of the present invention, restrictions in relative movement between the metallic and polymeric bodies are advantageously facilitated by virtue of contact therebetween. For example, it is preferred for at least one protrusion of one of the bodies to be mated with at least one shoulder, cavity or hole of the other body in a manner that restricts relative movement between the bodies. It is preferred for at least one of the protrusions and corresponding cavities (e.g., grooves) to be annular and contain an o-ring, for sealing purposes.

According to one aspect of the present invention, the polymeric body does not extend for the entire length of the metallic body. In accordance with one embodiment of the present invention, a forward end of the polymeric body, that defines the forward opening, is readily viewable, whereas the other, rearward end of the polymeric body is positioned between the ends of the metallic body and is, therefore, substantially hidden from view.

In accordance with one aspect of the present invention, the polymeric body is formed by injecting molding material through a hole in the sidewall of the metallic body. In accordance with some embodiments of the present invention, the sidewall is cylindrical, and the hole extends radially away from the axis which the cylindrical side wall extends around. The hole in the sidewall of the metallic body is preferably for receiving the molding material from a gate in a jig that holds the metallic body in a predetermined manner. It is preferred for the hole to be positioned between the forward, viewable end of the polymeric body and the substantially hidden, rearward end of the polymeric body. Preferably the hole is closer to the rearward end of the polymeric body than it is to the forward end of the polymeric body. This advantageously helps to ensure that the polymeric body is fully and properly formed within the metallic body. It is preferred for the polymeric body to include a protruding portion that at least partially occupies the hole, which further secures the bodies to one another. Each of the composite fittings can include at least one additional hole, which is for having molding material injected thereinto, and associated structures.

In accordance with one aspect of the present invention, the readily viewable forward end face of the polymeric body includes indicia.

Further to one aspect of the present invention, the metallic body of the composite fitting includes at least one spiral thread, which can be internal or external, for facilitating connection of the composite fitting to a piece of plumbing by twisting. The piece of plumbing preferably includes metallic thread(s) for mating with the thread(s) of the metallic body. The metallic body can include an outer polygonal portion for being engaged by a wrench, for facilitating the twisting.

In accordance with one aspect of the present invention, an internal stop, which is preferably annular and part of the polymeric body, protrudes into the passageway for engaging an end of the polymeric pipe, or other piece of plumbing, inserted into composite fitting, for arresting relative movement between the composite fitting and the piece of plumbing (e.g., polymeric pipe). Likewise, it is preferred for an internal or external stop, which is preferably annular and part of the metallic body, to be available for engaging an end of the metallic pipe or fitting, or other piece of plumbing, installed to the composite fitting, for arresting relative movement between the composite fitting and the piece of plumbing (e.g., metallic pipe or fitting).

In accordance with one aspect of the present invention, the composite fitting is advantageously compact as compared to comparable conventional fittings.

Other aspects and advantages of the present invention will become apparent from the following.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1-3illustrate a composite fitting20that is suitable for connecting between pieces of plumbing such as, but not limited to, polymeric and metallic pipes, in accordance with an exemplary embodiment of the present invention. Although the composite fitting20is often described herein in the context of connecting between polymeric and metallic pipes, the composite fitting20has other uses that are not limited to connecting between polymeric and metallic pipes. As one example, rather than being connected to a metallic pipe, the fitting20can be connected to other devices that can have metallic threads, such as valves, fittings or other pieces of plumbing, or the like, that can be associated with plumbing fixtures or appliances. Those of ordinary skill in the art will understand that there are a wide variety of uses for the composite fitting20; and the present invention is not intended to be limited to the embodiments described herein.

The composite fitting20includes a polymeric body22that is preferably molded into and fixedly connected to a metallic body24, and the bodies are preferably coaxial. The polymeric body22can consist essentially of polymeric material, and the metallic body24can consist essentially of metallic material. The polymeric body22is preferably fixed to the metallic body24by conforming to the internal surface of the metallic body, as will be discussed in greater detail below. It is preferred for the metallic body24to extend around the polymeric body22, so that the metallic body advantageously reinforces the polymeric body.

The polymeric body22extends around and is preferably contiguous with (e.g., contacts/defines) a portion of a passageway26that extends through the composite fitting20, and the polymeric body defines a forward opening28to the passageway26. The forward opening28is preferably part of a receptacle of the composite fitting20that is for internally receiving the polymeric pipe, as will be discussed in greater detail below. Similarly, and as best understood with reference toFIG. 3, the metallic body24extends around and is preferably contiguous with (e.g., contacts/defines) a portion of the passageway26of the composite fitting20, and the metallic body24defines a rearward opening30to the passageway26. As illustrated inFIGS. 1-3, the rearward opening30is part of an open plug portion32of the metallic body24that is for externally receiving the metallic pipe. The plug32preferably includes an external spiral thread34for connecting the plug to the metallic pipe, or the like, by twisting, as will be discussed in greater detail below. On the other hand, the thread34can be omitted and the connection can be facilitated by other means. As illustrated inFIGS. 1-3, the forward opening28and the rearward opening30are the only openings to the passageway26.

As best understood with reference toFIGS. 1,2and4, the metallic body24preferably includes an outer polygonal portion36, which is preferably hexagonal, for being engaged by a wrench, to facilitate twisting of the composite fitting20for installation purposes, as will be discussed in greater detail below. As best understood with reference toFIG. 5, which is an isolated cross-sectional view of the metallic body24, it includes annular, outwardly extending, forward and rearward cavities or grooves38,40that respectively include annular, outwardly extending shoulders which encircle, and preferably extend perpendicularly with respect to, the central axis of the metallic body. As best understood with reference toFIG. 4, it is preferred for a cylindrical hole42to extend through a cylindrical sidewall44of the metallic body24. The hole42preferably extends radially away from the central axis of the metallic body24. That is, the hole42preferably extends angularly away from the passageway26through the composite fitting, and most preferably an angle of about 90 degrees is defined between central axes of the hole and the passageway.

As best understood with reference toFIG. 6, which is an isolated view of the polymeric body22, it preferably includes a generally cylindrical, annular midportion46. Annular, outwardly extending, forward and rearward protrusions48,50are at opposite ends of the midportion46/polymeric body22. The protrusions48,50respectively include annular, outwardly extending shoulders that encircle, and preferably extend perpendicularly with respect to, the central axis of the polymeric body22. The polymeric body22further includes a protrusion or stub52that extends outwardly from the outer surface of the midportion46. The stub is preferably cylindrical and extends radially away from the polymeric body22.

The forward protrusion48of the polymeric body22includes a forward end face54that faces away from the metallic body24, and extends around and defines the forward opening28. As illustrated inFIGS. 1 and 3, the end face54is at least about flush with the adjacent end of the metallic body24, and preferably the end face and the adjacent end of the metallic body are substantially flush. In accordance with the exemplary embodiment of the present invention, the surface area of the forward end face54is sufficiently broad so that it can be molded to include, or otherwise marked to include, indicia (e.g., letters, numbers, symbols and/or other markings for conveying information). As illustrated inFIG. 2, exemplary indicia56of the forward end face54can be seen in an end elevational view of the composite fitting20.

Referring toFIG. 6, the rearward protrusion50of the polymeric body22includes a rearward end face58that faces one of the shoulders of the metallic body24and is hidden from view in the assembled configuration of the composite fitting20. In accordance with the exemplary embodiment of the present invention, the rearward protrusion50includes an outwardly open, annular groove60that, together with the rearward groove40(FIG. 5) of the metallic body24, contains/encases a polymeric o-ring61(FIG. 7) in the assembled configuration of the composite fitting20. In accordance with an alternative embodiment of the present invention, the o-ring61is omitted.

The assembled configuration of the composite fitting20can be best understood with reference toFIGS. 1 and 3, and with occasional reference also toFIGS. 5 and 6. Relative movement between the bodies22,24is advantageously restricted by virtue of the contact between the bodies, with that contact resulting from the polymeric body having been molded into the metallic body. For example, the protrusions48,50(FIG. 6) of the polymeric body22respectively extend into the grooves38,40(FIG. 5) of the metallic body24, so that the shoulders of the protrusions and grooves respectively engage one another in a manner that restricts relative movement between the bodies at least in the axial direction. Likewise, the stub52(FIGS. 1,3and6) of the polymeric body22closes and occupies (e.g., plugs) the hole42(FIGS. 1 and 4) of the metallic body24in a manner that restricts relative movement between the bodies in the axial direction. The stub52can substantially fill the hole42. In addition, the stub52occupies the hole42in a manner that restricts relative rotation between the bodies22,24about the central axis of the composite fitting20. That is, in accordance with the exemplary embodiment of the present invention, the polymeric and metallic bodies22,24are connected to one another without requiring that the metallic body be bent for facilitating this connection; therefore, the composite fitting20is advantageously not weakened by the connecting. In accordance with alternative embodiments of the present invention, one or more of the stub52, hole42, grooves38and40, and protrusions48and50are omitted, and it is within the scope of the present invention for other contact between the polymeric and metallic bodies22,24to restrict undesired relative movement therebetween.

As shown inFIGS. 2 and 3, in accordance with the exemplary embodiment of the present invention, the polymeric body22further includes an annular, inwardly extending protrusion62having annular shoulders which encircle, and preferably extend perpendicularly with respect to, the central axis of the composite fitting20. One of the shoulders of the protrusion62functions as a stop for engaging an end of a polymeric pipe inserted into the forward opening28. The stop feature of the protrusion62is for arresting relative movement between the polymeric pipe and the composite fitting20. The other shoulder of the protrusion62is for engaging a corresponding shoulder of the metallic body24for reinforcing the protrusion62and for further securing the bodies22,24to one another. In accordance with an alternative embodiment of the present invention, the inwardly extending protrusion62can be omitted and/or replaced with another component that functions as a backstop for the polymeric pipe.

As best understood with reference toFIG. 3, in accordance with the exemplary embodiment of the present invention, the length L1of the polymeric body22is less than the length L2of the metallic body24. Preferably the length L1is about 33% to about 67% of the length L2, and most preferably the length L1is about 43% of the length L2. Also in accordance with the exemplary embodiment of the present invention, the plug portion32of the metallic body24has a smaller outer diameter than the remainder of the metallic body. As a result, an outer and outwardly extending annular shoulder63of the metallic body24can function as a stop for engaging an end of a metallic pipe or fitting installed onto the plug portion32, for arresting relative movement between the composite fitting20and the metallic pipe or fitting.

FIG. 8schematically illustrates a coupling, which includes the composite fitting20and a metallic fitting64, connecting a polymeric pipe66and a metallic pipe68so that they are in fluid communication with one another, in accordance with the exemplary embodiment of the present invention. In accordance with one example of the exemplary embodiment of the present invention, the metallic pipe68is connected to the metallic fitting64in a conventional manner, such as by soldering, or the like. InFIG. 8, the metallic pipe68is partially illustrated by broken lines as extending into an opening of a passageway that extends through the metallic fitting64. The metallic pipe68and the metallic fitting64can be together referred to as a metallic pipe. For the embodiment illustrated inFIG. 8, an opening of the passageway that extends through the metallic fitting64includes internal threads70that are hidden from view and are, therefore, schematically illustrated by broken lines inFIG. 8. The external threads34(FIGS.1and3-5) of the composite fitting20are threaded into the internal threads70of the metallic fitting64by relatively twisting the fittings. Accordingly, broken lines inFIG. 8illustrate the composite fitting20extending into the passageway that extends through the metallic fitting64.

As alluded to previously, the composite fitting20can be connected to items other than the metallic fitting64and metallic pipe68. For example, other plumbing items can be connected to the composite fitting20in place of the metallic fitting64and metallic pipe68. As one example, the threads34of the composite fitting20can be mated with metallic threads of valves, fittings or other pieces of plumbing, or the like, that can be associated with plumbing fixtures or appliances. Those of ordinary skill in the art will understand that there can be a wide variety of uses for the composite fitting20.

An end of the polymeric pipe66is inserted into the forward opening28(FIGS. 1-3) of the composite fitting22and secured therein by way of solvent welding, adhesives, or the like. Broken lines inFIG. 8illustrate the polymeric pipe66extending into the forward opening28of the composite fitting20. Although not illustrated in the figures, and as best understood with reference toFIGS. 1 and 6, it is preferred for the entirety of the annular edge of the polymeric body22that defines the forward opening28(e.g., the edge of the of the polymeric body22which is located at the inner periphery of the forward end face54) to be slightly rounded or chamfered in a manner which facilitates insertion of the pipe66into the forward opening28.

In accordance with the exemplary embodiment of the present invention, the metallic body24is brass, or the like, and the metallic pipe68is copper, or the like. In accordance with alternative embodiments of the present invention, the metallic body24and metallic pipe68are constructed of other metals, and they can include, or be constructed of, materials other than metals. In accordance with the exemplary embodiment of the present invention, the polymeric body22and the polymeric pipe66are chlorinated polyvinyl chloride (CPVC), or the like. In accordance with alternative embodiments of the present invention, the polymeric body22and pipe66are constructed of polymers other than CPVC, and they can include, or be constructed of, materials other than polymers.

FIG. 9schematically illustrates a portion of a molding machine72for forming the composite fittings20, in accordance with the exemplary embodiment of the present invention. It is preferred for the molding machine72to manufacture multiple of the composite fittings20simultaneously; however, and for purposes of clarifying this disclosure, only a representative portion of the molding machine72is illustrated inFIG. 9. As schematically illustrated inFIG. 9, the machine72includes an actuator74for moving a mold insert76relative to a jig78. The actuator74moves the mold insert76between a molding configuration and a loading configuration. As will be discussed in greater detail below, the composite fitting20is formed during the molding configuration. In contrast, the loading configuration is for loading and unloading, as will be discussed in greater detail below.FIG. 9schematically illustrates the molding configuration, in which the metallic body24is hidden from view within the closed jig78, and a portion of the mold insert76is hidden from view within the jig and the metallic body; and these hidden from view items are schematically illustrated by broken lines inFIG. 9.

FIGS. 10 and 11are partial, isolated, cross-sectional views of the jig78, in its closed configuration, respectively taken along lines10-10and11-11ofFIG. 9.FIGS. 10 and 11illustrate that the openable and closable jig78includes opposite halves. The opposite halves of the jig78are closed/locked together during the molding configuration of the molding machine72, and they are unlocked/separated from one another during the loading configuration of the molding machine. When closed/locked together, the opposite halves of the jig78together define a receptacle80for initially holding a metallic body24and subsequently holding a composite fitting20formed by molding a polymeric body22into the metallic body being held. In accordance with the exemplary embodiment of the present invention, the receptacle80of the jig includes adjacent polygonal and cylindrical envelopes that are respectively illustrated inFIGS. 10 and 11. The polygonal envelope ofFIG. 11is most preferably hexagonal and is for closely engaging and extending around the hexagonal portion36(FIGS. 1 and 2) of the metallic body24. The cylindrical envelope ofFIG. 10is for closely engaging and extending around the outer surface of the cylindrical sidewall44(FIGS. 1-3) of the metallic body24.

Referring toFIG. 10, the receptacle80is for holding the metallic body24in a predetermined position so that the hole42(FIGS. 1 and 4) in the sidewall44of the metallic body is aligned with a gate82(e.g. passageway for supplying molding material) of the jig78during the molding configuration. Referring toFIG. 9, the gate82is in fluid communication with conventional equipment84for providing molding material under pressure, and the gate is for injecting the molding material into the hole42. The gate82and portions of a supply channel86connecting the gate to the equipment89that is the source of molding material are hidden from view inFIG. 9; therefore, broken lines illustrate them.

The molding configuration is partially illustrated inFIG. 12, which is a cross-sectional view taken along line12-12ofFIG. 10and is illustrative of the jig78in its open configuration, in accordance with the exemplary embodiment of the present invention. In the molding configuration, the metallic body24is held in the predetermined configuration in the jig78and the mold insert76is in the passageway through the metallic body24so that an annular chamber88is defined between the metallic body and the mold insert. The metallic body24extends around the chamber88and the chamber88extends around the mold insert76. At the same time, the mold insert76annularly engages surfaces of the metallic body24so that the chamber88is substantially closed, except for being in communication with the gate82. In accordance with the exemplary embodiment of the present invention, the mold insert76generally resembles a cylindrical rod that is tapered in somewhat of a stepped fashion so as to include a predetermined arrangement of annular bevels and shoulders. The cross-section of the mold insert76that is illustrated inFIG. 12is preferably representative of all straight cross-sections that can be taken through and perpendicular to the central axis of the mold insert. Although it is preferred for the metallic body24to contain the o-ring61(FIGS. 3 and 7) during the molding of the polymeric body22, the o-ring is omitted fromFIG. 12to clarify the view.

During the molding configuration illustrated inFIG. 12, the molding material (e.g., liquid CPVC) is injected into the chamber88via the gate82and the hole42, so that the hole42functions as an injection point by way of which the molding material is introduced into the chamber88. This injecting is carried out so that the chamber88and hole42are preferably completely filled, and then the molding material in the chamber88is allowed to solidify, so that it becomes the rigid polymeric body22. That is, the polymeric body22is preferably formed in the metallic body24by injection molding. As will be discussed in greater detail below, it is preferred for the molding material to be injected with sufficient pressure and/or under other conditions so that the o-ring61is compressed in a radially outward direction during the injection molding, so that the o-ring can, if required, subsequently expand and contract to compensate for any differences in the expansion and contraction of the polymeric and metallic bodies22,24and thereby enhance leak-proof functioning of the composite fitting20. The molding machine84is transitioned to the loading configuration after the injection molding.

In the loading configuration of the molding machine24, the mold insert76has been withdrawn preferably at least from the receptacle80(FIGS. 10 and 11) of the jig78. Then, the jig78can be opened and the composite fitting20can be removed from the jig. In accordance with the exemplary embodiment of the present invention, breaking the composite fitting20away from the polymeric material that solidified in the gate82and channel86completes fabrication of the composite fitting. That is, an annular shoulder/face91(FIG. 12) of the mold insert76preferably includes indicia (not shown) so that the indicia56(FIG. 2) of the composite fitting20is formed during molding of the polymeric body22. Solidified polymeric material in the gate82and supply channel86is preferably cleared prior to forming the next composite fitting20. Then, a metallic body24can be placed in the receptacle80of the jig78and the molding machine84can be returned to the molding configuration.

As best understood with reference toFIG. 3, the hole42in the sidewall44of the metallic body24is preferably positioned farther from the forward end face54of the polymeric body22than from the hidden, rearward end face58of the polymeric body. This advantageously helps to ensure that the polymeric body22is fully and properly formed within the metallic body24. That is, from a quality control standpoint, a visual confirmation that the readily viewable forward end face54of the polymeric body22is fully formed should advantageously also serve as a confirmation that the hidden, rearward end face58and other portions of the polymeric body are fully formed, since the hole42is closer to the rearward end face than it is to the forward end face. In accordance with alternative embodiments of the present invention, the hole42is arranged differently, and it is possible that the hole42could be omitted, such as by including the gate82(FIGS. 9 and 12) in the mold insert76rather than the jig78.

FIG. 13is a cross-sectional view of a composite fitting20′ that is like the composite fitting20described with reference toFIGS. 1-12, except that the composite fitting20′ ofFIG. 13includes an internally threaded receptacle90for internally connecting the composite fitting20′ to a metallic pipe or fitting. The threading of the internally threaded receptacle90terminates proximate an inner and inwardly extending annular shoulder92. The shoulder92can function as a stop for engaging an end of a metallic pipe or fitting installed into the receptacle90, for arresting relative movement between the composite fitting20′ and the metallic pipe or fitting.

FIG. 14is a cross-sectional view of a portion of a composite fitting20″ that is, in accordance with a first embodiment of the present invention, like the composite fitting20described with reference toFIGS. 1-12, and that is, in accordance with a second embodiment of the present invention, like the composite fitting20′ ofFIG. 13, except that for each of these first and second embodiments, the metallic body24″ further includes an axial groove94which is occupied by an axial protrusion96of the polymeric body22″. Each of the axial groove94and the axial protrusion96encircles and extends preferably parallel to the central axis of the metallic body24″. As illustrated inFIG. 14, the axial groove94includes a pair of shoulders that are radially spaced apart from one another, and that are each coaxial with the central axis of the composite fitting20″. Accordingly, in accordance with the first and second embodiments of the present invention, the metallic body24″ includes annular grooves that extend nonparallel to one another, the polymeric body22″ includes annular protrusions that extend nonparallel to one another, and the protrusions are respectively positioned in the grooves in a manner which seeks to stabilize the composite fittings/allow the composite fittings to function optimally.

FIGS. 15-17illustrate a composite fitting20′″ in accordance with another embodiment of the present invention. The composite fitting20′″ is like the composite fitting of the second embodiment of the present invention except that the metallic body24′″ of the composite fitting20′″ is modified. The metallic body24′″ is angled, such as to define a 90° angle, so that the composite fitting20′″ is in the form of an elbow. That is, the portions of the passageway26′″, which respectively include the openings28and30′″, respectively extend around axes, and an angle is defined between these axes, such as angle of 90°. Other angles are also within the scope of the present invention. Also, the metallic body24′″ includes ears or lobes100that are generally of the type that are included in conventional drop ear elbows. A hole102extends completely through each of the lobes100. Fasteners, such as nails or screws, can be inserted through the holes102for the purpose of mounting the composite fitting20′″ to a reference structure, such as a stud or other structural component of a building, or the like. Also, the metallic body24′″ optionally includes an annular flange98that encircles the opening30′″. As illustrated inFIGS. 15-17, the metallic body24′″ does not include the outer polygonal portion36(e.g., seeFIG. 1), but the metallic body24′″ can optionally include the outer polygonal portion36.

In accordance with exemplary embodiments of the present invention, feature(s) of the composite fittings advantageously operate in a manner which seeks stabilize the composite fittings/allow the composite fittings to function in a leak-proof manner for very many years, even if exposed to many extreme cycles of stress, such as may be caused by variations in the pressure and/or temperature of the water or other medium passing through the composite fittings. In this regard, and for example, it is preferred to incorporate the o-ring61as described above, because it can perform a sealing function that negates effects of different coefficients of expansion between the metallic and polymeric bodies. In this regard, it is believed that the functionality of the o-rings61can be enhanced by compressing (e.g., “flattening”) the o-rings in a radially outward direction when molding the polymeric bodies into the metallic bodies, so that the o-rings can, if required, subsequently expand and contract to compensate for any differences in the expansion and contraction of the metallic and polymeric bodies.

Such compressing of the o-rings61during manufacture can be enhanced, for example, by decreasing their modulus of elasticity, such as by preheating the o-rings. As an additional example, the molding material (e.g., see the source of molding material84inFIG. 9) can be injected in a manner that enhances the compressing of the o-rings61, such as by injecting the molding material at higher pressures, increasing the duration of the injecting, or making the pressure gradient of the injected molding material more uniform. As one example, and as best understood with reference toFIGS. 9 and 10, which only show one gate82per receptacle80, it may be possible to achieve a more uniform pressure gradient by injecting the molding material into each receptacle through more than one gate, such as via two gates which are diametrically opposed, or the like.