US2827618A

US2827618A - Shielded electrical connector

Info

Publication number: US2827618A
Application number: US340292A
Authority: US
Inventors: Chapman Joseph Edward Geoffrey; Dixon Henry Johnson; Harwood Frederick Arthur; Harthman Francis Peter
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1952-03-10
Filing date: 1953-03-04
Publication date: 1958-03-18
Anticipated expiration: 1975-03-18
Also published as: DE1043448B

Description

March 18, 1958 J. E. .G. CHAPMAN ET AL SHIELDED ELECTRICAL CONNECTOR 4 Sheets-Sheet 1 Filed March 4, 1953 INVE OR March 18, 1958 J. E. G. CHAPMAN ET AL 2,327,618

SHIELDED ELECTRICAL CONNECTOR Filed March 4, 1953 4 Sheets-Sheet 2 .F/GB.

March 18, 1958 J. E. G. CHAPMAN ET AL 2,827,618

SHIELDED ELECTRICAL CONNECTOR 4 Sheets-Sheet 3 Filed March 4, 1953 QM 1 NH J G E ATTOQNE) Mal'ch 1958 J. E. G. CHAPMAN EI'AL 2,827,618

SHIELDED ELECTRICAL CONNECTOR 4 Sheets-Sheet 4 Filed March 4, 1953 F/G/Zz 73- 75 y May/a e, wfiwgv ATTOk/VE) United States Patent F SHIELDED ELECTRICAL CONNECTOR Joseph Edward Geoiirey Chapman, Workington, Cumberland, Henry Johnson Dixon, West Kirby, Frederick Arthur Harwood, Maghull, near Liverpool, and Francis Peter Harthman; Liverpool, England, assignors to British Insulated Callenders Cables Limited, London, England, a British company Application March 4, 1953, Serial No. 340,292 Claims priority, application Great Britain March 19, 1952 7 Claims; (Cl. 339-143) This-invention relates to electric cable coupling devices as used for connecting together electrically the cable conductors of one length of cable with those of another or of some other electrical apparatus. The coupling device embodies contact members which are electrically connected to the ends of the conductors of the cable to be coupled, and are supported in a body of moulded insulating material. It will be understood that before the moulding operation can be carried out a certain amount of preliminary Work upon the end of the cable will have to be done. This will include the removal of the outer covering or coverings of the cable to expose the insulated cable conductors for an appropriate' distance. It will also include the removal of the insulation from the exposed cable conductors for an appropriate distance so that the contact members may be electrically'connected subsequently to the cable conconstructed and manufactured according to the present invention has this and other advantages.

According to the invention an electric cable coupling device comprises an inner body of moulded insulating material, in which those portions of the cable-conductors extending" beyond-the cut back end, are embedded, and an outer body or" moulded insulating material which surrounds and extends beyond'the' inner body and supports contact members electrically connected to the cable conductors.

The method of manufacturing an electric cable coupling device according to the invention, comprises exposing the component 'parts'of the cable for appropriate distances, moulding a body of insulating material around those portions of the cable conductors projecting beyond the main body of the cable, to form an inner body of insulating material, electrically connecting contact members for the coupling device to the projecting ends of the cable conductors and then moulding a second body of insulating materialaround the inner body to support the contact members.

The invention will be described further with the aid of the accompanying drawings wherein:

Figure 1 is a cross-section of one form of construction or" electric cable, to which the present invention is applicable,

Figure 2 is a perspective view of the cable shown in Figure 1, but after certain operations have been carried out on the cable,

Figure 3 is a sectional elevation of the end of the 2,827,618 Patented Mar. 18, 1958 cable inside a two-part mould, ready for the first moulding operation,

Figure 4 is a half sectional elevation of the moulded body formed by the first moulding operation,

Figure 5 is an end elevation of Figure 4, looking in the direction of the arrow,

Figure 6 is a half sectional elevation of the end of the cable and or" the moulded body shown in Figure 4, but

after certain further operations have been carried out,

Figure 7 is a sectional'elevation of a two-part mould with the'end of the "cable ready for the carrying out of the-second moulding operation,

Figure 8 is ahalfsectional elevation of the end of the cable showing the-moulded body produced by'the mould of Figure 7-,

Figure 9' is an end elevation of Figure 8, looking in the direction of the arrow,

Figure 10 is a half sectional elevation of the completed cable coupling device,

Figure 11 is an end elevation of Figure 10, looking in the direction'of the arrow, and

Figure 12 is a part half sectional elevation.

The coupling device illustrated in the accompanying drawings is shown applied to one form of construction of electric cable of the kind used with television cameras. The arrangement of the cable conductors will be seen from Figure 1 of the drawings. At the inner part of the cable there are six individually insulated conductors 1 arranged in pairs, the two conductors of each'pair being embedded in a body of insulating material 2. Over each of such bodies is applied a metal braided screen 3 and over each of the latter there is applied helically an impregnated textile tape 4. Each pair of insulated conductors together with its outer layers forms a unitary structure and is referred to as a core. The three cores are laid up helically together. On the outside of these cores are provided three groups of conductors 5, each group consisting of three individually insulated conductors, the reference numerals 6 indicating the insulation. The three conductors of each group are not laid up together helically but are laid in the helical interstices formed between the three cores. Over the three cores and three groups of insulated conductors 5 is applied a circular layer of individually insulated conductors 7,

their insulation being shown at 8. The insulated conductors 7 are applied helically and an impregnated textile tape 9 is wrapped helically over those conductors. Over the tape 9is applied a metal braided screen 10 and over the latter is applied a sheath 11 of polyvinyl chloride. The conductor insulation in each case is polyethylene and the cable has a total of thirty-six conductors. Although certain spaces between some of the insulated conductors are shown in the figure, this has been done for the sake of clarity. As will be understood these spaces will not exist in the cable as manufactured.

Before the end of the cable can be adapted for coupling, it is necessary to remove therefrom for an appropriate distance the sheath 11 'andalso to remove the insulation from the various conductors for a suitable distance. "In the particular construction of cable illustrated, it will be necessary also to make electrical connections to the metal screenslocated within the cable and to carry out various other operations which form part of the necessary preliminary Work upon'the end of the cable. The completion of this preliminary work is illustrated in Figure 2 to which reference will now be made. To the right of that figure the cable conductors are shown splayed out. This has been done merely to show clearly those opera tions which have been performed on them. The sheath 11, screen 10 and tape 9 are out back fromthe coupling end of the cable for appropriate distances. At or adjar cent the cut back end of the cable are provided two

metal clamping rings

12 and 13. The exposed end of the screen if is opened out and formed into a number of separate ends. These'ends ars'saown at 14 and are enmped'between the two

rings

12 and 13. The ring 13 hasa series of ci-rcu'mferentially arranged untapped holes which register with similarly arranged tapped holes in the ring 12.

The two rings are held together by screws 17 passing through the untapped holes and screwing into the tapped holes. The screws have lock nuts 18.

The insulation is removed from each cable conductor so that it terminates at a short distance beyond the cut back end of the sheath 11. The screens 3 and tapes 4 are cutback, the ends'of the latter being held in place by wrappings 19 of insulating'material and the ends of the screens 3, by wi'appings 28 of insulating material. Over the projecting insulated end of each conductor is placed 7 and insulating sleeve 21 of varnished cambric and the three screens 3 areelectrically connected to each, other and to the ring 13 by winding a piece of bare wire 28 around the three screens and soldering the wire to them and retaining one end of the wire between a washer 29 on one of the screws 17 and the metal ring 13. All these preliminary operations are carried out and completed before the contact members are attached to the ends of the conductors.

The ends of the conductors projecting beyond the cut back end of the sheath 11 are well splayed out and those rportionsvenclosed by the insulating sleeves 21 are embedded in a body of insulating material. This operation is carried out by enclosing the end of the cable and the projecting portions of the insulated conductors in a mould 23, shown in Figure 3, and injecting under pressure an insulating material in a heated plastic or viscous state,

the material solidifying or setting when allowed to cool.

.From Figure 3 it will beseen that the mould fits round a metal sleeve 24 which closely surrounds the sheath 11. v

The metal sleeve is integral with a flange 25 which is integral with a lateral extension 26 of the ring 12, the latter and the flange 25 forming between them an annularrecess 27. The mould 23, when placed in position, fits around :the cable end against the flange'25 and encloses the metal rings '12 and 13 and those portions of the conductors provided with the insulating sleeves 21.

The mould 23 consists of two main parts adaptedto be fitted and held together around the end of the cable.

.An aperture 30 in a side wall 34 of the mould provides for the injection under pressure of the insulating material into the mould through a'nozzle 31. The side wall of the mould has a second aperture 32 extending through it and through a small boss 33 extending inwardly from the in per surface of rthe side wall; The wire 28 electrically con- ..n-ecting the screens 3 and the ring 13 is taken through the .aperture' 32 to the outside of themould 23. The latter is closed by a removable end plate 35 provided with apertures through which the bared ends of the conductors project in the manner shown'in Figure 3. The injection of the insulating material into the mould 23 produces a small recess 37 as shown in Figure 4, the wire 28 projecting beyond this recess to the outside of the insulating body. In this moulding operation the screws 17 and nuts 18 and the portion of the wire 28 lying within the mould 23 are embedded in the insulating body 36.

In Figure 6, the moulded body 35 is shown with a metal screen 38 partly enclosed by the body and extending beyond it in the longitudinal direction or" the cable.

. support the moulded body 36 with clearance between it and the inner surface of the mould.

This screen is arranged to surround the three pairs of con-' ductors 1 (Figure l) at their ends and the contact members connected to those ends.- The'end of the screen 38 nearer to the cut back end ofthe cable is housed in a recess ofja n appropriate shape formed in the'moulded body 36 during themouldiug operation already described The shape-of the recess receiving the screen will beseen from Figure 5 where the recess 'is shown at 39. The latter is composed of a portion 48 of circular cross-section, radial ductors;

portions 41 and a central longitudinally extending portion 42 of circular cross-section. The screen 38 is of cor- V responding shape and, as will be seen from Figure 9, consists of a portion 43 of cylindrical cross-section, through which extends an axially disposed rod 44 and three fins 45 extending between the central rod and the portion 43.

The screen 38 is electrically connected to the ring 13 by a bare wire 46 (Figure 6) which is connected to the 'erid of the screen 3 nearer the ring 13. The wire 46 is housed in a curved passage 47 in the moulded body 36, the passage extending from the central portion 42 of the recess to the outsideof the moulded body where it terminates at the recess 37. The recess 39 and the passage 47 are 7 formed during the moulding'operationalready described. Referring again to Figure 3, the inner side of the end plate 35 is provided with a series of projections 48 which together form a pattern of the shape required to form the recess 39. A part of the circular portion 46 and of the central portion 42 of the recess are shown in Figure4.

The curved passage 47 is produced by forming the moulded, body 36 around a flexible core 53 having a smooth curve in it and of larger diameter than the wire 46. The core'is anchored at one end in any convenient manner and extends through the centre one of the projections 48 and through the end plate 35 to the outside thereof. Afiter the moulding operation the core is withdrawn from the moulding. A curved wire or other smooth flexible member of suitable material may be used for the core. The wire 46 connected to the screen 38 is threaded through the "passage 47 so that it extends beyond the moulded ,body 36, the screen 38 at the same time being guided into its recess 39. The screen 38 can be electrically'connected to the'ring 13 by suitably joining the outer ends of the

wires

28 and 46. A

of the moulded body 36 and at this stage are only supported by their attachment to the conductors. The operations required for the attachment and supporting of the pins, however, are not commenced until the completion of all the preliminarysteps required to prepare. an end of the cable. 1

The end of the cable, the moulded body 36 and the pins attached thereto and the screen 38 which has now been placed in its recess, are now enclosed in a second mould 50, as shown in Figure 7. The mould is of twopart construction. Screws (not shown) passing through the wall of the mould and entering the tapped holes 62 To prevent the injected insulating material completely enclosing the pins 49, a' plate 81 is formed with recesses 51 which receive the end parts of the pins. A second body of insulating material is moulded round the moulded body 36 by injecting 'under pressure insulating ma terial' atone end of the mould-59 through a nozzle '52 at the side of the mould and communicating with a passage 54 and passages 55 in a member 80, the passages 55 communicating-with passages 82 extending through'the plate 81 into the interiorof the mould 50. This opera- ,tion results inthe formation of an outer moulded body 56 as shown in Figure 8; --The outer moulded body fills up the recess 37 in the side of the inner mouldedbody' 36 andit supports the pins 49 firmly in position; Itlalso 'supports the. screen 38firmlyin position and insulates the connections made between the wires 46 and 38I FromFigure 8. itwill be seen that the. insulating material of the outerinoul'dd body 56 has entered the recess 27 and surrounded the flange 25 and that it has also extended beyond the flange to enclose a portion of the sleeve 24 and that at that part, the moulding is formed with an annular recess 58 and a flange 59'. The

entry of the insulating material into the recess 27' and the enclosure of the flange 25 in the insulating material pro vides for an interlocking of the metal ring 12 and the outer moulded body 56. The annular recess SS and flange 59 'are formed during the moulding of the body 56'by' an inwardly extending projecting portion 61 of the inner surface of the mould and an annular recess 66 in that surface, as shown in Figure 7.

Ingthe particular construction of coupling device illustrated, the contact members consist of the pins 49 and assuming that two lengths of cable are to be coupled the second length of cable will be provide at its end with a coupling device embodying contact members having the form of sockets, coupling being effected by a relative axial movement of approach of the two coupling devices to bring the pins 49 into engagement with the sockets.

In Figure 10, there is shown a coupling ring 64 which encloses the exposed ends of the pins 49 and the inner surface of which has at the outer end of the ring a screw-threaded portion 65. The coupling ring 64 is carried by a metal sleeve 66 which surrounds and makes a close fit with the outer body 56 of moulded insulating material. The sleeve is made of sufficient length to extend over the two clamping rings 13 and 12 and for a short-distance beyond the latter. The sleeve is retained in position by being attached by a number of screws 67 which pass through holes in the sleeve and enter the holes 62, which are tapped, in the metal clamping ring 12., Thesleeve 66 is of substantial thickness and affords mechanical protection for the inner and outer moulded bodies of insulation against damage. Should, however, the sleeve 66 or the coupling ring 64 become damaged, a new coupling ring and sleeve can be fitted readily by removing the screws 67 and drawing forward the old ring and sleeve and replacing those parts by a new ring and sleeve and attaching the latter to the coupling ring 12 bythe screws 67. The fact that the coupling ring 64 and sleeve 66 can be placed in position after the cornpletion of the moulding operations is of advantage as it facilitates the appropriate setting up of the cable condoctors in the moulds preparatory to the carrying out of the moulding operations and the attachment and replacement of the sleeve 66 and coupling ring 64 can be carried out without disturbing the

moulded bodies

36 and 56 .of insulating material or the cable conductors or pins attached thereto. As the coupling ring 64 and sleeve 66 are not placed in position until after the completion of the second moulding operation, the attachment of the pins 49 to the ends of the cable conductors after the completion of the first moulding operation is facilitated since the exposed ends of the conductors are freely accessible. The pins may be conveniently attached to their cable conductors by a soldering operation.

Over the sleeve 66 is placed a stout flexible sleeving 69 made of rubber, for example, which interlocks with the flange 59 forming part of the outer moulded body 56. At that end of the sleeve 69 adjacent the coupling ring 64, the sleeve is held in tight contact with the sleeve 66 by a binding 70.

The coupling ring 64 has three circumferentially spaced recesses formed in its inner surface. These are shown in Figure 11 being indicated by the reference numerals retained in position in the manner previously described. The figurealso shows a sleeve 72 having in its-outer surface an annular recess receiving a ring 73. The sleeve 72 has at its outer end three circumferentially spaced projections 74, their spacing and'dimensions corresponding .to those of the recesses 71? Figure 12 shows one only of the projections '74. The recesses and projections areso arranged that engagement of the pins 49 and their sockets can be effected only when the pins are in axial alignment with their correct sockets, so that the required electric connections between the cable conductors of the two lengths of cable are obtained.

A rotatable coupling ring 75 having an externally threaded spigot'portion 76 engages the screw-threaded portion 65 of the couplingring 64; The coupling ring 75 is rotatable on'the sleeve 72 but is prevented from longitudinal movement along'the sleeve by the ring -73 and by the projections 74 which form abutments for the spigot portion 76 of the clamping ring 75. Due to the fact that the latter can rotate on but not move axially of the sleeve 72, rotation of'the coupling ring 75 and engagement of it with the coupling ring 64 will result in a relative axial movement of approach of the pins 49 and their sockets and the engagement of those members, the two coupling rings hold the pins and sockets in engagement.

In the particular construction of cable described above, there is an outer screen 14), three inner screens 3 and an additional screen 38'and the preliminary steps efiected and completed before the attachment of the contact members to the ends of the cable conductors consist in removing the conductor insulation for an appropriate distance, placing insulating sleeves over the projecting ends of the cable conductors to provide additional insulation at those parts, placing the wrappings 19 and 20 in position, connecting the outer screen and the three inner screens to clamping rings placed round the cable adjacent its out back end and providing for the making of an electrical connection from the additional screen 38 to the clamping rings 12 and 13. It will be understood, however, that the actual steps to be carried out as preliminary work before the attachment of the contact members to the cable conductors will depend upon the construction of the cable. In the construction of cable described, the screens forming a part of the cable construction and the additional screen are all electrically connected to the clamping ring 12 and through the screws 67, sleeve 66 and coupling rings 64 and 75 and sleeve 72 to clamping rings similar to the

rings

12 and 13 and from thence to the corresponding screens of the' second length of cable, when the two lengths of cable are coupled together. Electrical continuity and earthing of all the screens can thus be readily obtained although the additional screen 38 is embedded in the two moulded

bodies

36 and 56 of insulating material. though in the particular construction as described, the rings12 and 13 have been stated to be both made of metal, it may be an advantage in some cases to make one of them of insulating material in order to avoid excessive conduction of heat from the mould to the cable conductors during the mould ing operation.

What we claim as our invention is:

1. An electric cable coupling device comprising a length of electric cable having an end at which the cable conductors project beyond an outer covering of the cable, a metal ring surrounding the cable adjacent the termination of the outer covering of that end, an inner body of insulating material having a recess, a screening device seating in the said recess projecting belond the inner body which latter has a passage extending from the recess to the outside of the inner body, a conducting lead housed in the passage electrically connected to the screen and to the metal ring surrounding the cable, the inner body surrounding the cable conductors individually and collectively, and an outer body of insulating material surrounding the inner body 7 V I 'of that body, and contact'members electrically connected 'ing devices and having an end at which thecable cona and means for attaching the metal ductors project beyond an outer covering-of the cable, a 7

pair of clamping members surrounding the cable adjacent the termination of the outer covering at thatend, an adjacent end of the outer screen lying between and being clamped between the two clamping members, a con ducting lead electrically connecting the inner screen and one of the clamping members, an inner body of insulating material surrounding the cable conductors individually and collectively and'also surrounding. the-said conducting lead, an outer body of insulating material surrounding the inner body and extendingover a face thereof, and contact members electrically connected to the cable conductors and surrounded individuallyrand collectively by the outer body,beyond which latter :the contact members project. l j

3. An electric cable coupling device, comprising a length of'electric cable having an end at which the-cable conductors project beyond an outer covering of the cable, a clamping device for a screen in the cable, surrounding .the cable adjacent its end and being supported. by the cable, contact members attached to the ends of the cable conductors, a first block of'insula ing material mounted in axial alignment with the end of" the-cable and closely surrounding the contact members and holding them in spaced relationship, a second block of insulating material mounted in axial alignment with the end of the cable and in abutting relationship with that end and with the clamping device and also with the first block of insulating material, the second block of insulating material having its outer surface lying substantialr a 8 a 0nd block of insulating material and the two rings and making interlocking engagement with the groove in the extension of the metal ring'and surrounding the end of the cable, a removable metal sleeve-closely surrounding the two blocks of insulating material and the two rings, sleeve to the metal ring. v t

g 5. An electric cable coupling device, comprising a length of electric cable having an end at which the cable conductors project beyond an outer covering of the cable, a clamping device for a screen embodied in the cable, surrounding theicable adjacent its end and being supported by the cable, contact members attached to the ends of the cable conductors, a first rigid block of insulating material closely fitting around the contact members holdingthem in spaced and in iusulative relationship, A a second rigid block of insulating material interposed between the first rigidrblock of insulating material and the endlof the cable, embedding the projecting ends 'of the cable'conductors and holding them in spaced relationthe second rigid block of insulating material and over ly flush with that of the clamping deviceand embedding the projecting ends of the cable conductors and'holding them in spaced relationship, a sleeve of' insulating material integral with the first block of insulating material and extending rearwardly thereof and surrounding the second block of insulating material, the clamping device and the end of the cable, the sleeve making interlocking engagement with the clampingdevice and being of reduced thickness-where it surrounds the second block of insulating material" and of greater thickness where it makes interlocking engagement'with'the clamping device and Where it surrounds the end of the cable,-aremovable metal sleeve surrounding'the first and second blocks of insulating material and the clamping device and'means for attaching the metal sleeve to the clamping device:

4. An electric cable coupling'device; comprising a length of electric cable having an end at which the cable conductors project beyond an outer covering of the cable, a pair of rings surrounding andsupported by the cable, at least one of the rings being of metal, means for drawing the two rings together to clamp there'between an end of a screen, an annular extension of thei'metal ring surrounding the cablemudhaving a-groove; contact members attached to the ends of the cable conductors, a'first block of insulating material closely fitting-around the contact members and holding them in spaced relationship, a second block'of insulating material interposed between the first block and the endof the cable and making abutting contactwith the first bloclgthe end of-the cable and one of the rings=surroundingthe cable; the said second block embedding theprojecting ends of the-cable conductors and holding themin;spaced relationship and having its outersurface lying substantially fiushwith that of the adjacent ring, :a-s'leeve'of inulating material integral with the first block of insulating'material extending'bacl wards towards. the cable'andiclosely surrounding the sec ship, the second block of insulating material being anchoredto the clamping device, a sleeve of insulating material integral with the first rigid block of insulating material extending rearwardly towards the cable end over the clampiugdevice and surrounding the end of the cable, the twoblccks and clamping device providing a rigid unitary structure attached to the end of the cable, and a metal sleeve closely surrounding the two rigid blocks of insulating material and the sleeve integral with the first rigid block and extending over the clamping device and removablemeans for securing the sleeveto the clamping device, the lmetal sleeve aflording mechanical protection to the members enclosed thereby and having mounted upon that end of the cable and attached thereto and projecting forwardly thereof and a multiplicity of contacts each connected to a cable conductor mounted in the part of the structure remote from the end of the cable, the said unitary structure comprising a first rigid block of insulating material holding the contacts in spaced insulative relationship, a secondrigid block of insulating material between the end of the cable and the first block embedding the cable conductors, a thin walled sleeve of insulating material integral with the first block and having its outer surface flush withrthat of the first block, extending over the second block and making a close fit therewith, a screen-clamping device on the end of the cable anchored to the second block, the sleeve extending over the second block and having and end portion of substantially" greater wall thickness surrounding closely the end of the cable and interlocked withthe clamping device, the first block and the thin walled insulating sleeve providing a cylindrical outer surface, a detachable metal sleeve closely fitting over the first rigid block and its sleeve and the screen clamping device and removable means securing the sleeve to the clamping device. V I

7. An electric cable coupling device, comprising a length of electric cable having an end at which a multiplicity of cable conductors'p'roject beyond an outer covering of the cable, and a rigid unitary structure mounted upon and attached to that end of the cable and projecting O forwardly thereof anda multiplicity of contacts each conthe contacts being mounted in the first block and held by that block in insulative spaced relation and the'cable conductors being embedded in the second block, a screen clamping device mounted on the cable and anchored to the second block, a thin Walled sleeve having an outer surface flush with that of the first block extending rearwardly towards the cable over the second block and the clamping device, a thin walled metal sleeve integral with the clamping device and closely surrounding the end of the cable, the thin walled insulating sleeve extending rearwardly beyond the clamping device where it has a wall of substantially greater thickness fitting closely 10 around the metal sleeve integral with the clamping device, a metal sleeve fitting over the first block, its insulating sleeve and the clamping device and removable means securing the metal sleeve to the clamping device.

References Cited in the file of this patent UNITED STATES PATENTS Davis Sept. 6, 1927 Schmitt Feb. 23, 1943 Webber July 10, 1945 Rifenbergh Dec. 18, 1945 Miller et al Mar. 19, 1946 Martin Nov. 16, 1948 Steinke Feb. 21, 1950 Lefren July 18, 1950 Hennessoy Dec. 8, 1953 Dixon May 29, 1956