US3500298A - Multicontact connector assembly - Google Patents

Description

March 10, 1970 .1. B. P. WILLIAMSON ET 3,500,293

MULTICONTAGT CONNECTOR ASSEMBLY Filed June 21, 1967 2 Sheets-Sheet 1 FIG.I

1a 12 17 ll 13 flN INVENTORS d. B. P. WILLIAMSON R. L5HERWOOD March 10, 1970 J. B. P. WILLIAMSON ETAL 3,500,298

MULTICONTACT CONNECTOR ASSEMBLY Filed June 21, 1967 2 Sheets-Sheet 2 FIG.6

INVEN ORS J. B. P. WILLIAMSON R. L.6HERWOOD United States Patent 3,500,298 MUL'I'ICONTACT CONNECTOR ASSEMBLY John B. P. Williamson, Wilton, Conn., and Ralph L.

Sherwood, Westfield, N.J., assignors to Burndy Corporation, a corporation of New York Filed June 21, 1967, Ser. No. 647,750 Int. Cl. H01r 9/08 U.S. Cl. 339-217 Claims ABSTRACT OF THE DISCLOSURE The following disclosure relates broadly to snap-in connectors comprising, a housing, a multi-layered block of dielectric material bonded to the housing and having at least one connector hole passing coaxially through the block. The multi-layered block is formed of a rigid resinimpregnated wafer having bonded to each face thereof a sub-member of elastomeric material. A retainer member of spring material is positioned in at least one connector hole and is secured to the wafer, the retainer being formed with a cylindrical sleeve portion and a plurality of spring fingers projecting therefrom, the sleeve portion being fitted snugly within the connector hole in the wafer and being bonded thereto with the projecting spring fingers thereof extending into one of said elastomeric sub-members.

The invention relates to an electric connector, and, in particular, to a multicontact connector assembly and a method for producing said connector.

Multicontact connectors are well known for use in connecting and disconnecting a large number of electric circuits, such as prevail in aircraft, communication systems, and the like. Such connectors have individually removable contacts whichare joined by crimping or soldering to conductors. The advantage of having a removable contact is that if it is bent or otherwise damaged to render it useless, it may be replaced without scrapping the entire connector. In one form of connector, the coupling of the contact pin to the connector assembly is achieved via a hollow resilient retaining member or spring which is removably mounted within a bore of a connector block of insulating material, the retainer being cylindrical in shape and comprising a sleeve portion with spring fingers projecting therefrom, the fingers being adapted to grip a contact pin insertable therein. The sleeve is split to enable it to be spring fitted into the bore, the outer surface of the sleeve having an annular shoulder which cooperates with a complementary annular shoulder in the bore of the block to secure the retainer in place.

Retainers of this type are generally produced by an automatic screw machine from rod material fed through the machine. Such machining operations add to the cost of the retainer as well as to the entire cost of the connector assembly, since the bore of the block must be also configurated to match the shoulders machined into the surface of the retainer. The retainer and the bore must be precisely machined so that the retainer can be securely locked in the bore and resist a pull-out force of 15 pounds or more.

It would be desirable to provide a multicontact connector assembly produced by more economical means and in which the retainer is unremovably secured to the bore of the insulating block.

It is an object of the invention to provide a new and improved multicontact connector assembly.

Another object is to provide a method of making a multicontact connector assembly wherein the retainer portion of the connector block is unremovably secured to the bore of block.

These and other objects will more clearly appear when 3,500,298 Patented Mar. 10, 1970 See taken in conjunction with the followuxg disclosure and the accompanying drawings, wherein:

FIGURE 1 is a fragmented illustration of one type of a prior art connector assembly wherein the retainer is of the removably insertable type;

FIGURE 2 shows a plurality of strips of fibrous fabric, such as fiberglass fabric, prior to impregnation with a heat curable resin and prior to lamination;

FIGURES 3 to 5 are illustrative of perforated wafers produced from epoxy impregnated fiberglass cloth, the impregnant being in the B-stage condition, each of the perforations being adapted to receive the sleeve portion of a retainer member;

FIGURE 6 is a fragmented cross section of a multicontact connector assembly showing the wafer portion of the assembly positioned against an annular shoulder of a metal housing surrounding a multilayered block of dielectric material, the wafer comprising one of the layers of the block; while,

FIGURE 7 is similar to FIGURE 6 except that the wafer portion of the multilayered block has an annular shoulder for fitting against a corresponding annular shoulder of the metal house.

FIGURE 1 shOWs a connector of the snap-in type, comprising a block of insulating material 10, e.g. a phenolic resin or other plastic, having a circular bore 11, a portion of which bore is reduced in diameter at 12. Snap fitted into the bore is a removable retainer member 13 of spring material, eg beryllium-copper, having a sleeve portion 14 which is split and a plurality of projecting spring fingers, such as fingers-15 and 16, the split extending past the projecting fingers. By compressing the retainer during insertion, it is caused to snap or spring-fit in place and held against longitudinal displacement in the bore via annular shoulders 17 and 18 acting on corresponding shoulders in the sleeve which is recessed to form a complementary fit with the reduced diameter of the bore. Inserted into the retainer is a contact member 19, the forward portion 20 of which extends through and past the spring finger of the retainer, the contact member having exterior surfaces and shoulders which complement similar surfaces and shoulders to interlock the member and the member and the retainer as shown. The contact member is provided with end bores 21 and 22 for receiving conductor pins, for example of the type designated by number 22a.

As stated earlier, it is important that the retainer of the type 13 shown in FIGURE 1 be firmly locked in position so as to resist a pulling force of at least 15 pounds. Thus, care must be taken that the shoulders 17, 18 of the reduced portion of the bore are precise and not chipped, otherwise the retainer may dislodge itself whenever a pull is applied to one or more conductors coupled to the retainer via contact pins of the type similar to 22a.

According to the invention, this is avoided in that the retainer is permanently secured to the bore of a multilayered block comprising a rigid resin-impregnated wafer of fibrous cloth sandwiched between and bonded on each side to sub-members of elastomeric material.

Broadly stated, the invention provides a snap-in connector assembly comprising, a housing, a multilayered block of dielectric material bonded to the housing and having at least one connector hole passing coaxially through the block. The multilayered block is formed of a rigid resin-impregnated wafer having bonded to each face thereof a sub-member of elastomeric material. A retainer member of spring material is positioned in at least one connector hole and is secured to the wafer, the retainer being formed with a cylindrical sleeve portion and a plurality of spring fingers projecting therefrom, the sleeve portion being fitted snugly within the connector hole in the wafer and being bonded thereto with the projecting spring fingers thereof extending into one of said elastomeric sub-members.

A preferred method employed for producing the snapin connector assembly of the invention comprises providing a B-stage resin-impregnated e.g. epoxy-impregnated wafer of fibrous cloth, e.g. fiberglass cloth, having at least one connector hole passing through it and sandwiching it between a pair of elastomeric sub-members also having at least one connector hole to form a multilayer block, the hole in each layer being indexed with the other to provide a continuous bore for receiving a contact pin. A spring retainer having a cylindrical sleeve portion and projecting spring fingers is fitted into the bore with the sleeve portion snugly nesting in the wafer portion. The outer surface of the multilayered block is coated with a layer of B-stage epoxy resin and the block inserted into a properly dimensioned metal housing. The parts are placed in a jig and subjected to an elevated temperature to cure the resin and effect bonding between the epoxy-impregnated wafer and the elastomeric submembers, and between the multilayered block and the housing. During the curing operation, the sleeve of the retainer is bonded within the opening of the cured wafer and rigidly anchored to it. The wafer is rigid and provides adequate support for the retainer.

The resin-impregnated wafer may comprise a single layer of fiberglass cloth having a thickness ranging from about 0.03 inch to 0.10 inch or it may comprise a lamina tion of layers. Whatever the form of the wafer, the resin impregnant should be the B-stage so that when the parts making up the multilayered insulator block are assembled together, the B-stage resin can then be cured to bond all the parts together.

Referring to FIGURE 2, three layers 25, 26, 27 of epoxy-impregnated fiberglass cloth are shown prior to being laminated together, the epoxy-based adhesive being in the B-stage. As stated above, where it is desired, the fiberglass or other fibrous cloth may constitute a single layer.

After the three layers are laminated together and the epoxy impregnant allowed to dry, a wafer 28 is cut out as shown in FIGURE 3, the wafer being perforated with holes 29 for receiving a properly dimensioned retainer member. FIGURE 4 is a cross section taken along line 44 of FIGURE 3 showing the three layers of fiberglass cloth making up the wafer. FIGURE is similar to FIGURE 4, but illustrates a wafer made from a single layer of resin-impregnated cloth.

FIGURE 6 shows the parts making up the insulator block assembled together with a metal housing 30 of aluminum or other metal. The wafer 31 which is in the form of a perforated disc is disposed in abutting relationship with annular shoulder 32 of the housing, the wafer being sandwiched between similarly perforated submembers 33, 34 of elastomeric material, the parts being indexed so that a plurality of bores 35 are provided running through the resulting multilayered insulating block. Fitted into each perforation of the wafer is a retainer 36 having a sleeve portion 38 with projecting spring fingers 37 adapted to receive and grip contact pins inserted into bores 35. The sleeve portions of each of the retainers snugly fit into the perforations as shown.

As stated above, the wafer is impregnated with B-stage resin. In addition, the B-stage resin is applied to the surface of the sub-members at 39 and 40 which are in contact with the inner wall of the metal housing. A B-stage resin is one which will thermoset or harden when subjected to an elevated curing temperature. After the parts are assembled, the resulting multicontact connector is subjected to a curing cycle by heating the assembly, for example, at a temperature within the range of about 125 C. to 325 C. for upwards of about 30 minutes, such as from 3 to 20 minutes, whereby the resin is caused to flow at the contacting surfaces and harden to form a strong adhesive bond betwe n the re a ner and the Wafer,

between the wafer and sub-members 33 and 34, and between the multilayered block and metal housing 30.

FIGURE 7 is similar to FIGURE 6 except that wafer 31 is peripherally stepped to provide a shoulder 41 to abut against a corresponding shoulder on the inner wall of the housing.

Epoxy resins are preferred as the adhesive in that they exhibit excellent toughness, adhesion, chemical resistance, and in addition have excellent dielectric properties. Other resins which may be employed in the B-stage are polyester resins and phenolic resins, among others. A commonly used epoxy adhesive is one obtained by reacting epichlorohydrin with Bisphenol A in the presence of sodium hydroxide or potassium hydroxide catalyst. The reaction is given as follows.

(catalyst is NAOH or KOH) Various types of curing agents may be incorporated in the resin, such as amines, acids, anhydrides, aldehyde resins, etc. Heating, curing or thermosetting resins may have a molecular Weight ranging from about 500 to 4000.

Novalac resins may be used in place of Bisphenol A. Thus the epoxy resin may comprise either Bisphenol A/epichlorohydrin or Novalac/epichlorohydrin. Both of these are applied to the fibrous or fiberglass cloth as solutions and the impregnated cloth is thereafter dried to provide a thermosettable B-stage resin which hardens on heating.

The sub-members making up the insulator block are made of elastomeric material so as to provide a good sealing fit with the contact pin. The elastomeric sub-memhers may be made of silicone rubber, natural rubber, neoprene, butyl rubber, Buna N, polyether urethanes, polyester urethanes, ethylene-propylene rubbers, phosphonitrilic rubbers and the like.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art will readily --understand. Such modifications and variations are considered to be within the purview and scope of the invention.

What is claimed is:

1. A snap-in connector assembly comprising, a housing, a rnulti-layered block of dielectric material resinbonded to said housing and having at least one connector bore passing coaxially through said block, said multi layered block being formed of a resin-impregnated wafer of fibrous cloth having resin bonded to each face thereof a sub-member of elastomeric material, and a retainer member of spring material inserted into and positioned in said at least one connector bore and resin-bonded within and along the length of an opening of said wafer coextensive with said bore, said retainer comprising a cylindrical sleeve portion and plurality of spring fingers projecting therefrom, said sleeve portion being positioned within the opening of said wafer with the spring fingers projecting from said wafer along said bore.

2. The snap-in connector assembly of claim 1 wherein the housing is provided internally with an annular shoulder and wherein said wafer of said multi-layered block is in abutting contact with said shoulder.

3. The snap-in connector assembly of claim 2 wherein the bonding resin is a cured epoxy-based adhesive and wherein the fibrous cloth is made of fiberglass.

4. The snap-in connector of claim 3 wherein the epoxybased adhesive is selected from the group consistin of the 5 compositions Bisphenol A/epichlorohydrin and Novalac/ epichlorohydrin.

5. The snap-in connector of claim 3 wherein the wafer comprises a laminate of fiberglass cloth.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 3/ 1965 Great Britain.

RICHARD E. MOORE, Primary Examiner US. Cl. X.R.

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