SEALED CONNECTOR HAVING UNITARY MOLDED HOUSING

Abstract: A dual molded sealed electrical connector having deformable seals (22, 24, 52) adhering to relatively rigid body portions (20, 50, 54) establishing sealing integrity for individual pin (70) and socket (80) terminals joining corresponding conductors. An interface seal (22) surrounds a cavity (32) containing one terminal (70) and receives a cylindrical protuberance (60) on the other connector housing (12). The seal (22) is deflected radially outward upon engaging a conical surface (60c) on the protuberance (60). The connector bodies comprise one-piece molded members formed sequentially of different materials in the same mold.

Description: This invention relates to electrical connectors for establishing an environmentally sealed multiple contact interconnection with a plurality of conductors and more specifically to the dual molding of connectors having a rigid portion and a deformable sealing portion in a unitary insulative housing. Electrical connectors employing matable connector halves in which one connector half has a plurality of cavities dimensioned to receive rigid insulating protuberances on a mating connector half are commonly employed to interconnect a plurality of separate wires or conductors. US-A-4.443.048 is an example of such an electrical connector assembly in which mating terminals are respectively retained within cavities in one housing and bores extending through the protuberances in the other housing. These cavities are secured to the relatively rigid housing and provide an efficient means for establishing an unsealed electrical interconnection between a plurality of conductors. US-A-4 640 567 (published February 3, 1987) discloses a multi contact sealed connector suitable for interconnecting a plurality of wires and providing seals to separately seal and isolate each individual terminal or circuit from the other circuits. Therefore, the sealing integrity of a single circuit does not affect the sealing integrity which can be maintained for other circuits or wires. Even if a particular terminal is removed from the connector housing, the remaining terminals and wires would still be sealed. The connector shown in that patent employs discrete seals both to maintain sealing integrity with conductors and to maintain sealing integrity at the interface between two separate connector halves, one connector half having a plurality of protuberances received within cavities in the other mating connector half. US-A-4 311 355 also discloses an electrical connector employing discrete seals. The use of separate discrete seals in the manner depicted in US-A-4 640 567 means that care must be taken and time expended to handle and account for each seal during assembly of the product The number of components in each electrical connector invariably adds to its cost of assembly. One technique for limiting the number of components in a sealed connector is disclosed in US-A-4 895 529 (published January 23, 1990) and EP-A-0 114 479. These publications disclose an electrical connector employing a one piece molded connector having a flexible sealing material chemically joined to a more rigid material of the type suitable for retaining and separating electrical contact terminals of the type normally used in detachable electrical connectors. The one piece housing depicted in the last two mentioned publications is formed by a dual molding process in which one material is first injected into a mold followed by the movement of core pins or sleeves to define one or more joining cavities into which the second material can be injected. US-A-4 601 528 (published July 22, 1986) also discloses an electrical connector employing a unitary housing having a relatively rigid and a relatively deformable portion. The present invention, however, is intended to provide a proven terminal and housing configuration in which the terminals are securely retained and protected within at least one cavity in one housing and at least one bore in at least one corresponding protuberance in the other housing to form a sealed interconnection for each circuit without the additional assembly required by the addition of discrete seals. A mating interface seal which surrounds the or each protuberance to form a seal, ensures that a satisfactory seal will be established upon mating where practical tolerances will not permit the exact location of one housing with respect to another sufficient to precisely compress a conventional seal. The present invention consists in a detachable electrical connector as defined in claim 1. The preferred embodiment of this invention comprises a sealed connector in which the matable plug and receptacle connector housings each constitute one-piece or unitary molded housings. Each housing, however, is formed of separate portions, molded in the same mold from different materials, and adhering to each other. The seals are relatively more deformable than the more rigid body portion and the seals establish sealing integrity with conductors entering the plug and receptacle and between the mated plug and receptacle. The receptacle housing body includes one or more cylindrical protuberances or silos which is insertable into a cavity on the plug housing. The mating seal is located on the receptacle, surrounding the cavity, and the protuberance is inserted through the mating seal. A conical surface at the base of each protuberance engages the seal and expands the seal radially outward when the plug and receptacle are fully mated. Individual pin and socket terminals are located within the protuberances and cavities and the mating seal individually seals each circuit path formed by mating pins and sockets. Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of an electrical connector assembly comprising two intermatable parts. Figure 2 is a cross sectional view of corresponding terminals positioned within mating portions of two separate housings, with the housings being in alignment prior to mating. Figure 3 is a view similar to Figure 2 in which the corresponding terminals and housing portions have been intermated and in which an interfacial seal on one housing component is shown in engagement with the other housing. Figure 4 is an end view of the rear conductor receiving end of the plug, which is is similar to the rear conductor receiving end of the receptacle. Figure 5 is an end view of the plug housing showing interfacial seals. Figure 6 is an end view of the receptacle housing when viewed along line 6-6 showing protruding silos. Figure 7 is an enlarged perspective view, partially in section of the interfacial seals prior to mating. Figure 8 is an enlarged perspective view of the portions of the silos mated with the interfacial seals. Figure 9 is a view partially in section showing the molding of the rigid portion of a single housing. Figure 10 is a view partially in section showing the molding of the relatively deformable sealing members on opposite ends of the housing. Figure 11 is a view partially in section showing withdrawal of the core pins from a single housing cavity. Figure 12 is a schematic of an alternate embodiment of the interfacial seals and the tooling used to fabricate the molded interfacial seals. Figure 13 is a sectional view taken along section lines 13-13 showing the contour of the interface between the interfacial seal and the rigid body portion of the alternate embodiment. Figure 1 depicts two mating connector housings 10 and 12 exploded and positioned in alignment. The preferred embodiment depicted herein consists of a four position electrical connector including means for independently sealing the conductors at each position at the rear conductor receiving end of both housings and for providing separate interfacial seal engagement around each terminal at the mating interface. Plug housing 10 shown in Figure 1 consists of a single molded member of insulative material including a relatively rigid portion 20 and two relatively more deformable flexible portions 22 and 24 located at the mating end and rearward end respectively. The central portion 20 exhibits sufficient rigidity to retain individual contact terminals 70 and 80 secured within the housing and originally positioned to permit engagement and resist the mating forces between the stamped and formed pin terminal 70 and the stamped and formed socket 80. A number of conventional plastic materials can be employed to fabricate the rigid portion of housing 20. The preferred material for use in fabricating housing 20 is a flame retardant polypropylene. A number of materials suitable for use in fabricating the rigid housing portion 20 are described in US-A-4 895 529 (published January 23, 1990). Integral latches 26 on opposite sides of the central rigid portion 20 are also integrally molded from the same plastic material as central portion 20. Latch 26 is sufficiently elongate to provide cantilever movement to permit the free end of the latch to move outward for engagement with the receptacle connector and then inward to latch the receptacle connector to the plug connector. The plug connector housing 10 also includes molded seals 22 and 24 at opposite ends of the central rigid connector housing 10. The connector half 10, although consisting of different sections of different materials is in fact a single or unitary molded member and is not an assembly of separate pieces. The relatively deformable or flexible sealing portions 22 and 24 are adhered to the central rigid body 20 along an interface at which the deformable portions exhibit an adherence by means of a chemical affinity to the rigid portion. The exact nature of this chemical affinity is described in greater detail in US-A-4 895 529 (published January 23, 1990). A suitable material for fabricating the deformable sealing members 22 and 24 would be one of several formulations of Santoprene, a dynamic vulcanizate comprising ethylene-propylene-diene-monomer (EPDM) rubber particles dispersed in a matrix of polypropylene. Santoprene is available from Monsanto Polymer Products Company. In the preferred embodiment of this invention, a silicone lubricant is added to the Santoprene material in the manner discussed in the above identified patent. This material constitutes a flexible elastomer and forms an interface with a rigid surface or with the insulation surrounding a conductor when deformed. In the preferred embodiment of this invention the forward or interfacial mating seal 22 comprises a single mass of deformable material. For the four position sealed connector depicted herein, a common base 22b is formed adjacent the interface with the rigid body 20. A plurality of cylindrical lips 22a extend upwardly from the common base 22b. The lips 22a are free standing and are capable of being outwardly deformed. The deformable lips 22a thus extend outwardly along the mating face 28 of connector housing 10 in positon to engage the opposite connector half 12 when mated. The interface between the rigid body 20 and seal 22 comprises a three dimensional nonplanar contour in the form right angle steps defined by surfaces 42, 43 and 44. This three dimensional nonplanar contour provides a greater surface area at the interface between seal 22 and the rigid body 20, thus increasing the adherence of seal 22 to rigid body 20. The conductor seal is formed at the rear of the housing 10 by a deformable seal 24 having a plurality of cavities 30 extending therethrough in alignment with cavities 32 in the rigid terminal housing 20. The deformable sealing portion 24 also comprises a single mass of deformable material with four generally cylindrical conductor seals 24a interconnected by webs 24b extending between the cylindrical seals 24a. Sealing ribs 24c and 24d are formed on the interior of the seals 24 and extend into sealing cavity 30. Insertion of a conductor through the sealing ribs 24 deforms the sealing ribs relatively outwardly and establishes sealing integrity around the conductor. Seal 24 is formed of the same material as seal 22 and is sufficiently deformable to permit the passage of a terminal through and past the ribs 24c and 24d and into the cavity 32 of the rigid housing. A connector receptacle 12 matable with the connector plug 10 is also formed with a relatively rigid body formed of sections 50 and 54 and a relatively deformable sealing portion 52 located at the rear conductor receiving end of the receptacle housing 12. The material forming the relatively rigid and relatively deformable portions of connector receptacle 12 can be the same as for the connector plug 10. The rigid body is divided into two sections by a central flange 56. Both rigid body portions 50 and 54 are formed of the same material as part of the same molding operations. As with the plug housing 10, the relatively rigid portions 50 and 54 and the relatively more deformable portion 52 all constitute a unitary molded member with a chemical affinity being established between the rigid portion 54 and the deformable sealing portion 52 along the interface therebetween. Sealing portion 52 is in all respects analogous to sealing portion 24 on the connector plug 10. The central flange 56 extends peripherally around the rigid body portion 50, 54. A sealing gasket 58 is adhered to the flange 56 in the same manner as the conductor seals and the interfacial seals are formed, and the gasket 58 forms a part of the one-piece molded connector housing. The formation of sealing gasket 58 occurs at a different time in the molding operation than the formation of flange 56, but the same surface on the mold tooling forms the interfacial surface of flange 56 as forms the free sealing surface of gasket portion 58. In the preferred embodiment, peripheral ridges 57 are formed on flange 56 and peripheral sealing ridges 59 having the same contour would be formed by the same surface on the mold tooling. This sealing integrity can be established with a bulkhead when receptacle housing 12 is attached by screws or other conventional fasteners to a bulkhead, wall or partition. The mating end 51 of the connector receptacle 50 is formed with a plurality of cylindrical protuberances or silos 60 extending from a base adjacent the rigid body portion 54. Each protuberance 60 has a free end 60a with a central bore 60d being defined by the cylindrical portion 60b of the silo or protuberance. An outwardly expanded conical section 60c is located at the base of the cylindrical portion 60b of silo 60. This conical portion 60c is continuous completely around the cylindrical portion 60b. The protuberance bore is coincident with a cavity extending through the rigid portion 54 and subsequently through each of the separate sealing bores providing room for conductor 18 in the seal portion 52. The terminals used in plug housing 10 and receptacle housing 12 are conventional. Terminal 70 comprises a crimped pin contact having a male pin leading edge 70a and crimped in conventional fashion at 70d to a stripped conductor 18. Pin terminal 70 has outwardly projecting lances 70b and outwardly projecting abutting surfaces 70c. Lances 70b are inwardly deflectable to permit insertion of the pin terminal into the cavity 32. Lances 70b and shoulder 70c abut constricted portions 36 and 33 within the cavity 32 formed in the rigid section of plug housing 10. Outwardly protruding lances 70b and shoulder 70c can be inserted through the sealing member 24 without significant damages to sealing ribs 24c and 24d. Socket terminal 80 mounted in receptacle housing 12 is matable with the pin terminal 70. A cylindrical socket portion 80a engages the pin portion 70a as shown in Figure 3 to form a stable electrical connection between conductors 18 extending into the rear of each housing. Socket terminal 80 has outwardly extending lances 80b and a shoulder 80c which serve the same purpose as lance 70d and shoulder 70c in the pin terminal 70. A crimp 80d of conventional construction interconnects the stamped and formed socket terminal 80 to a stripped conductor 18 in conventional fashion. Other embodiments of this invention might employ a pin terminal in the receptacle housing and a socket terminal in the receptacle housing. Figures 3 and 8 demonstrate the manner in which a separate seal connection is formed with corresponding conductors 18 at the rear of the plug and receptacle housing respectively and the manner in which a mating seal is established adjacent the mating face 11 of plug housing 10 and the mating end of receptacle housing 12. The outwardly deformable seal lips 22a engage the conical section 60c when plug housing 10 is mated with receptacle housing 12. As shown in Figures 7 and 8 each individual protuberance 60 is insertable into a cavity in the plug housing 10. The protuberance 60 is also insertable through the bore of the cylindrical sealing lips 22a. Two discrete sealing contacts are formed by the edges of the stepped surface of sealing lips 22a with the conical surface 60c. This sealing engagement is demonstrated schematically in Figure 8. Note that the sealing lips 22a expand outwardly. Deformation of the seals results in the formation of a suitable seal around each protuberance. Sealing integrity for the outwardly deflected cylindrical sealing lips 22a is not dependent upon the precise axial positon of the sealing lips 22a relative to conical surface 60c. Sealing integrity is first established soon after the interior of the sealing lips 22a engages conical surface 60c. Continued axial movement of plug housing 10 relative to the receptacle housing 12 results in continued expansion of the cylindrical seals 22a along the conical surface 60c. The cylindrical configuration of the seals permits a relatively large axial movement, and the tolerances of other elements on the housing do not become excessively tight. For example, unrealistically close tolerances for latch 26 and latching ears 66 are not necessary, because precise positioning of the seal 22 and the conical surfaces 60c are not essential. Figures 9 through 11 demonstrate the manner in which the connector housing 10 is formed as a unitary insulative body in a dual molding process in which two separate materials are used to form the body. As shown in Figure 9 the relatively rigid material is injected into a mold to form the rigid body portion 20, including latches 26. Axially shiftable sleeves 100, 102 and pin 104 are then withdrawn defining an additional cavity at the opposite ends of the rigid body portion. Elastomeric material can then be injected into this additional cavity and a chemical affinity will be established at the interface between the rigid body portion and the deformable portions 22 and 24. Note that the temperature of the rigid body portion 20 and sealing members 22 and 24 are elevated at the time this chemical affinity is established. Note that seal 22 is cylindrical in nature and can be formed by straight draw core pins without the need of complex coring to form laterally extending lips. It is this need to simplify the manufacture and construction of sealing member 22 that requires the use of outward deformation of the cylindrical seal upon engagement with the conical surface on the protuberance as the basic sealing mechanism of this connector. Note that the free end of the cylindrical sealing lips 22a has the same contour as the interface between the rigid portion 20 and the deformable portion 22. The three dimensional nonplanar contour formed by seal surfaces 22c, 22d and 22e is the same as the three dimensional nonplanar contour formed by surfaces 42, 43 and 44. This identity follows from the fact that each contour is formed by the same core pin. This stepped contour not only increases the surface area for the interface between the rigid and deformable housing portions, but also defines the two distinct sealing lips which engage conical surface 60c. Figure 11 shows the withdrawal of the core pins 108, 110 used to define the cavities extending through the rigid body portion 20. Note that ribs 24c and 24d are sufficiently flexible to deform upon withdrawal of the core pin which has constricted portions to form ribs 24c and 24d. Figures 12 and 13 show the manner in which an alternate embodiment of the present invention can be fabricated using simpler mold tooling than that shown in Figures 9-11. Primed reference numerals generally correspond to similar structures in the embodiment of Figures 1-11. Figure 12 shows the mating end of a one-piece plug connector housing 10' having an interfacial seal 22' adhered to a rigid body portion 20'. Independent deformable sealing lips 22a' are formed on the one-piece seal member 22' in the same manner as for the embodiment of Figures 1-11. The contour of the interface between the deformable seal portion 22' and the relatively rigid body portion 20' differs from that in the other embodiment. A projecting rib 22f', having no counterpart in the other embodiment, is shown in Figure 13. This projecting rib 22f' of the sealing portion 22' extends into a corresponding recess in the rigid body portion 20'. Significantly the contour of the outer end of sealing portion 22' matches the contour of the interfacial surface between the seal 22' and the rigid body portion 20'. These corresponding contours are again due to the fact that the same surface on the movable core pin assembly is responsible for sequentially molding each surface. This core pin assembly consists of cylindrical sleeves 100' and a central segment 104'. Unlike the tooling used with the embodiment of Figures 1-11, the central segment 104' is not movable relative to cylindrical sleeves 100'. The entire assembly moves at once and preferably can be formed from a single piece of metal. Core pins 108' move through sleeves 100' in the same manner as in the preferred embodiment. The rib 22f' does increase the surface area along which the seal 22' is joined to the rigid body portion 20'. This feature is secondary, however, and the formation of rib 22f' is primarily due to the fact that the contour of the free end should preferably define four independently expandable sealing lips 22f'. One skilled in the art would appreciate that a gap must be defined between each sealing lip, thus requiring the central segment 104' to extend beyond the cylindrical sleeves 100' of the tooling.

Claims: A detachable electrical connector for use in establishing an interconnection between conductors in one or more circuits comprising: a first (10) matable insulated connector housing being a unitary molded member and comprising a relatively rigid portion (20), a relatively deformable sealing portion (22) adjacent a mating face (11), and a cavity (32) extending through the relatively rigid portion (20) and the relatively deformable sealing portion (22); a second (12) matable insulated connector housing comprising a mating end (51) and a bore (60d) extending through the second (12) housing; and matable electrical terminals (70, 80) in the bore (60d) and the cavity (32); the connector being characterised by the second (12) housing further comprising on the mating end (51) a relatively rigid protuberance (60) through which the bore (60d) extends, whereby the cavity (32) receives the protuberance (60), and the relatively deformable sealing portion (22) establishes sealing integrity around the protuberance (60) when the first (10) and second (12) connector housings are mated. The electrical connector of claim 1 wherein each protuberance (60) has a free end adjacent the mating end of the second housing (12) and a base (60c), the base having a conical contour, the relatively deformable sealing portion (22) of the first housing (10) being at least partially outwardly expandable upon engagement with the conical contour of the protuberance base (60c). The electrical connector of claim 2 wherein the sealing portion (22) of the first housing (10) comprises at least one cylindrical lip (22a) extending outwardly from the mating face of the first housing (10). The electrical connector of claim 3 wherein a plurality of protuberances (60) are positioned side by side on the mating end of the second housing (12), and a plurality of separate lips (22a) are positoned on the mating face of the first housing (10) oriented in alignment with corresponding protuberances (60). The electrical connector of claim 3 wherein the cylindrical lip (22a) has a free end with a stepped contour (22c, 22d, 22e) comprising means for forming plural discrete sealing contacts upon engagement with the conical surface (60c). The electrical connector of claim 1 further comprising second relatively deformable sealing portions (24, 52) on a rear end of the first (10) and second (12) housings, the second relatively deformable portions (24, 52) comprising means for sealing a conductor after insertion of one of the electrical terminals (70 or 80) therethrough. The electrical connector of claim 1 wherein the relatively rigid portions (20) and the relatively deformable portions (22) are formed of different insulative materials joined together at the interface by a chemical affinity therebetween. The electrical connector of claim 1 wherein the relatively deformable portions (22) are formed of an elastomeric material. The electrical connector of claim 1 further comprising a rigid molded flange (56) extending from a relatively rigid portion of one connector housing and a peripheral molded sealing gasket (58) on one surface of the flange (56), the flange (56) and the sealing gasket (58) each being part of the one unitary molded connector housing (12). The electrical connector of claim 1 wherein each terminal (70, 80) is retained within a rigid portion (20, 50) of each housing (10, 12).

Inventors: LUNDERGAN, ROBERT GRAHAM, THAKRAR, ANIL C.
Applicants: AMP INCORPORATED
Application year: 1987
Main classification: H01R13
IPC codes: H01R13, H01R9