US3249907A - Sealed multi-contact electrical connector - Google Patents

Description

SEALED MULTI-CONTACT ELECTRICAL CONNECTOR Filed Aug. 23, 1963 4 28 IO l I United States Patent 3,249,907 SEALED MULTI-CONTACT ELECTRICAL CONNECTOR Frederick J. Hewitson, Tockenham, near Wootton Bassett, England, assignor to Plessey UK. Limited, a British company Filed Aug. 23, 1963, Ser. No. 304,726 Claims priority, application Great Britain, Aug. 28, 1962,

32,975/62; Oct. 11, 1962, 38,469/62 6 Claims. (Cl. -339--60) venting the connector element from being withdrawn from the insulating body by pull on the cable or wire. While a satisfactory resistance to withdrawal can be achieved in this manner if a divided rubber or like block is used, such a division of the block is not very satisfactory from an electrical point of view; in the absence of such division on the other hand, the need of introducing the flanged connector element axially through the narrower parts of the bore in which the element is lodged, limits the maximum diameter of the flanges to such an extent as to make it diflicult to achieve satisfactory pull-out'resistance.

The present invent-ion has for an object to provide an improved connector of the kind specified which provides additional pull-out resistance independent of the cooperation of the retention flanges with the rubber or like insulating body.

According to the invention the wire-receiving end of each connector element, or a rigid member attached thereto, is arranged to face at a close distance a retention plate or cap of rigid material which is supported on the connector housing, for example by being held in position by a cap nut co-operating with a thread on the circumfergnce of the connector housing. At least one, and preferably both, of the retention cap and sleeve consist of insulating mate-rial.

One embodiment of the invention is illustrated in the accompanying drawing, which is an elevation of a multipin connector plug member, partly in section along the axis of a contact element.

Referring now to the drawing, the illustrated plug member comprises an insulating :body 2 of moulded electrically insulating resilient material, for example rubber or silicone rubber, provided with suitably profiled through bores serving for the accommodation ofcontact elements 9, only one of which is shown, and which each include acontact pin 3 projecting through one end face, hereinafter called the front end, of thebody 2, while its rear end is attached to awire 4 projecting from insulation 5. This body is inserted in ametal shell 1 having an internal shoulder 1a against which a complementary shoulder of the body '2 rests, and external screw threads 1b for engagement by a cap nu-t 8 the crown of which has acentral bore 8a. The rear end of thecylindrical body 2 is tape-red as shown at 2a and co-operates with a corresponding internal taper of aretainer cap 6 of rigid insulating material, for example fibre-reinforced phenol-formaldehyde materal. This cap has abottom 6a, which is provided with wire-clearance apertures 6b in coaxial alignment with each contact-receiving hole of theinsulating body 2, the perforations 6b being a sliding fit on the covering 3,249,907 Patented May 3, 1966 ofconductor wires 4. Aretention sleeve 7, which consists of polystyrene, poly-tetrafluoroethylene, or other rigid insulating material and which has a tapered end portion 7b, is placed around thewire 4 between thecontact element 9 and theend wall 6a of theretaining cap 6 and is so dimensioned as to extend, when the connector is assembled, into close proximity to theend plate 6a of theretaining cap 6, which itself is held rigidly in position on theconnector housing body 1 by thecap nut 8. Both theretention sleeve 7 and theretaining cap 6 consist of material which is of rigid nature, in contrast to the resilient nature of themoulding 2 in which thecontact elements 9 are accommodated. Therefore if a pull exerted on thewires 4, 5, thecontact element 9 will be moved sufficien-tly to bring theretention sleeve 7 into contact with theend wall 6a of the retaining cap. This small amount of movement will be readily permitted by the resilience of thebody 2 without dislodging the locatingflanges 9a and 9b; thereafter the force of the pull will be transmitted direct from the body ofcontact element 9 via theretention sleeve 7, retainingcap 6, andcap nut 8, to the connector body .1, thus avoiding any risk of a contact element being dislodged and accidentally withdrawn from theresilient body 2.

To assemble the connector, theinsulated wires 4, 5, are each passed from the rear through thecentral aperture 8a of thecap nut 8 and threaded through the appropriate perforation 6b in theend wall 6a of theretainer cap 6. Aretention sleeve 7 whose end portion 7b serves to ensure sealing engagement with thebody 2, is then slipped over the stripped end of eachwire 4 to cover the end of the insulation 5, and thereafter the strippedwire end 4 is introduced into the axial bore of athimble'part 12 of thecontact element 9 equipped with thepin 3, and the cylindrical end portion 10 of theretention sleeve 7 is introduced into a cup-shapedwidened extension 11 of the thirnble part ofcontact element 9. The thim'ble part -12 of the contact element is then crimped to thewire 4, thereby trapping thesleeve 7 between thethimble 12 and the insulation 5 of the wire.

Thecontact body 9 is then pushed home into its seat in the resilient rubber or likebody 2, whereafter theretainer cap 6 ispushed towards thebody 2, and clamped to it by thecap nut 8. Thereafter thenut 8 is tightened,

whereupon thecap 6, due to its tapered bore, compresses theresilient body 2 to form a close seal on eachcontact element 9. When the edge of thecap 6 abuts the end of theshell 1, theend wall 6a of theretainer cap 6 will also be in contact with, or at least closely adjacent to, the end of theretention sleeve 7, so that, as mentioned above, any appreciable pull on thecontact element 9 by the wire will be transmitted by thesleeve 7,cap 6 andnut 8 to thebody 1 of the connector without undue strain upon the seating surfaces in themoulding 2.

The dimensions of the insulatingelastomer body 2 are so chosen that when the connector member is thus assembled, t-he elastomer body is subjected to a certain amount of compression due to the action of the inner cone surface of theretainer cap 6 upon the tapered end portion 2a of thebody 2. The conical shape of the last-mentioned surfaces improves the gripping and sealing action of the elastomer body around each contact element.

While a connector plug member has been described with reference to the drawing, it will be evident to those skilled in the art, that the invention is equally applicable to connector socket members, in which case'the illustratedpintype contact elements 9 are replaced by socket-type contact elements which, instead of carrying acontact pin 3, are formed with a pin-receiving socket bore. Various other features of the illustrated embodiment may also be modified within the scope of the invention. Thus while preferably both theretention sleeve 7 and theretainer cap 6 are made from insulating material, this is not essential for the operation of the invention so long as at least one of these elements is made of insulating material. For example thecap 6, which is subject to somewhat greater mechanical stress, may be made of aluminum or other metal, provided that theretention sleeve 7 consists of insulating material.

.What is claimed is:

1. An electrical connector member, comprising an insulating body of elastomer material having a'first and a second end face parallel to each other and at least one contact-receiving through bore extending between said end faces, a contact element positioned in each said contact-receiving through bore and at least accessible for contact engagement through the first of said end faces, and a connector housing in which said insulating body is secured with said first end face exposed and at least the ends of said through bores in the other end vface accessible through said housing for the insertion of an insulated Wire, the combination including a retaining plate' facing said second end face and at least supported in said housing, said plate having through bores respectively aligned with each of said through bores of the insulating body in at least one relative position of said plate, and at least one retention sleeve extending, when the connector member is assembled, over at least the greater part of the distance from such contact element to the opposed face of the retaining plate to transmit, direct from the contact element to the retaining plate and housing, at least after slight deformation of the elastomer body, any forces due to pull exerted upon a wire attached'to the contact element and extending through the retaining plate, both the retaining plate and the retention sleeve being made of substantially rigid material and at least one of them consisting of insulating material.

2. A connector member as claimed inclaim 1, wherein the connector housing comprises a screw-threaded shell and a cap nut.

3. A connector member as claimed inclaim 1, wherein the retaining plate forms the bottom of a retaining cap having a conical collar oooperating with a corresponding c'one surface on the elastomer body.

4. An electrical connector member as claimed inclaim 1, wherein the axial bore of the retention sleeve is stepped, forming a small-diameter portion to accommodate a length of stripped wire end, and a larger-diameter portion adapted for accommodating the end portion of the insulation of the wire.

5. A connector member as claimed inclaim 1, wherein each contact element is formed, at its wire-receiving end, with a wire-receiving thimble extended to form a cap into which one end of the retention sleeve fits.

6. An electrical connector member as claimed in claim 5, wherein the axial bore of the retention sleeve is stepped, forming a small-diameter portion to accommodate a length of stripped wire'end, and a larger-diameter portion adapted for accommodating the end portion of the insulation of the wire.

References Cited by the Examiner UNITED STATES PATENTS 2,939,906 6/1960 Harwood 339- X 2,984,811 5/1961 Hennessey et al. 339-94 X 3,104,145 9/1963 Somerset 339-103 FOREIGN PATENTS 830,192 3/1960 Great Britain.

PATRICK A. CLIFFORD, Primary Examiner.

ALFRED s. TRASK, Examiner.

Claims (1)

1. AN ELECTRICAL CONNECTOR MEMBER, COMPRISING AN INSULATING BODY OF ELASTOMER MATERIAL HAVING A FIRST AND A SECOND END FACE PARALLEL TO EACH OTHER AND AT LEAST ONE CONTACT-RECEIVING THROUGH BORE EXTENDING BETWEEN SAID END FACES, A CONTACT ELEMENT POSITIONED IN EACH SAID CONTACT-RECEIVING THROUGH BORE AND AT LEAST ACCESSIBLE FOR CONTACT ENGAGEMENT THROUGH THE FIRST OF SAID END FACES, AND A CONNECTOR HOUSING IN WHICH SAID INSULATING BODY IS SECURED WITH SAID FIRST END FACE EXPOSED AND AT LEAST THE ENDS OF SAID THROUGH BORES IN THE OTHER END FACE ACCESSIBLE THROUGH SAID HOUSING FOR THE INSERTION OF AN INSULATED WIRE, THE COMBINATION INCLUDING A RETAINING PLATE FACING SAID SECOND END FACE AND AT LEAST SUPPORTED IN SAID HOUSING, SAID PLATE HAVING THROUGH BORES RESPECTIVELY ALIGNED WITH EACH OF SAID THROUGH BORES OF THE INSULATING BODY IN A LEAST ONE RELATIVE POSITION OF SAID PLATE, AND AT LEAST ONE RETENTION SLEEVE EXTENDING, WHEN THE CONNECTOR MEMBER IS ASSEMBLED, OVER AT LEAST THE GREATER PART OF THE DISTANCE FROM SUCH CONTACT ELEMENT TO THE OPPOSED FACE OF THE RETAINING PLATE TO TRANSMIT, DIRECT FROM THE CONTACT ELEMENT TO THE RETAINING PLATE AND HOUSING, AT LEAST AFTER SLIGHT DEFORMATION OF THE ELASTOMER BODY, ANY FORCES DUE TO PULL EXERTED UPON A WIRE ATTACHED TO THE CONTACT ELEMENT AND EXTENDING THROUGH THE RETAINING PLATE, BOTH THE

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