Title:
ELECTRICAL CONNECTING DEVICES FOR TERMINATING CORDS AND METHODS OF ASSEMBLING THE DEVICES TO CORDS
United States Patent 3860316


Abstract:
A one-piece plug for terminating a cord to connect electrically the cord to components in a telephone apparatus is constructed with features advantageous to the assembly of the cord with the plug. The plug has a dielectric housing molded with a cord-input aperture in the one end thereof. The jacket is removed from a leading portion to expose individually insulated conductors. Then an end portion of the cord is inserted into the cord-input aperture in the housing until individual conductors are received in conductor-receiving troughs and until the leading end of the jacket abuts a shoulder formed internally of the housing. Forces are applied to a jacket anchoring member formed integrally of the housing to partially disconnect it from the housing and move it into engagement with the jacket. Another portion formed integrally with the housing is reformed into a strain relief element in engagement with the conductors to provide strain relief for the conductors. Flat blade-like terminals are inserted into the dielectric housing to move internal contacting portions thereof through the insulation and into engagement with the conductors. External contacting portions of the terminals engage associated components of the telephone apparatus when the plug is inserted thereinto.



Inventors:
HARDESTY EDWIN CHARLES
Application Number:
05/377154
Publication Date:
01/14/1975
Filing Date:
07/06/1973
Assignee:
WESTERN ELECTRIC COMPANY, INCORPORATED
Primary Class:
Other Classes:
439/425, 439/460
International Classes:
H01R4/16; H01R4/24; H01R12/08; H01R12/38; H01R13/58; H01R13/50; (IPC1-7): H01R13/54
Field of Search:
339/91,97,98,99,176MF,103,107
View Patent Images:
US Patent References:
3761869CONNECTOR1973-09-25Hardesty et al.
3699498DEVICES FOR MAKING ELECTRICAL CONNECTIONS1972-10-17Hardesty et al.
3621449ELECTRICAL CONNECTORS1971-11-16Bridle
3576518SOLDERLESS CONNECTOR FOR INSULATED WIRES1971-04-27Bazille et al.
3569914CONNECTOR HOUSING1971-03-09Taylor et al.



Primary Examiner:
Frazier, Roy D.
Assistant Examiner:
Hafer, Robert A.
Attorney, Agent or Firm:
Somers E. W.
Claims:
What is claimed is

1. An electrical connector for terminating a cord having a plurality of insulated conductors and for making electrical contact external to the connector, which comprises:

2. An electrical connector for terminating a cord having a plurality of insulated conductors and for making electrical contact external to the connector, which comprises:

3. The electrical connector of claim 2, wherein the at least one moveable portion of the housing includes an anchoring member formed integrally with the housing along at least a portion of the periphery of the anchoring member such that compressive forces applied to the anchoring member reforms the anchoring member into a wedge-shaped element locked in engagement with the cord and the housing to provide strain relief for the cord during use thereof.

4. The electrical connector of claim 2, wherein the conductor-receiving troughs open to the free end of the housing.

5. The electrical connector of claim 2, wherein the conductor-receiving troughs terminate in a wall forming at least a portion of the free end of the housing to seal off the troughs from the free end of the housing.

6. The electrical connector of claim 2, wherein a free end of the housing extends beyond the remaining portion of the housing to provide a bearing surface for cutting off exposed end portions of the conductors which extend beyond the free end of the housing.

7. The connector of claim 2, wherein the terminals are blade-like and the terminal-receiving openings include a plurality of spaced slots opening to an external surface of the housing and communicating with associated ones of the troughs, each of the slots being of a size to permit the first contact portion of the associated one of the terminals to pass therethrough.

8. The connector of claim 7, wherein the first contact portions of each terminal includes a plurality of contact tangs which extend through the associated one of the slots and into electrical engagement with the conductor in the associated trough.

9. The connector of claim 7, wherein each of the terminals is formed with barbs extending therefrom and which are positioned within the associated one of the slots, an overall longitudinal dimension between extremities of the barbs being slightly greater than the longitudinal dimension of the slot which communicates with the associated trough to facilitate the barbs of the terminal becoming embedded in the walls of the slot when the terminals are inserted to anchor the terminals within the housing at a predetermined depth within the housing.

10. The electrical connector of claim 7, wherein the housing is also formed with a plurality of spaced fins upstanding from the external surface to which the terminal-receiving slots open, each of the fins interposed between the longitudinal axes of two adjacent ones of the slots, the fins capable of guiding external contacting elements into engagement with second contact portions of associated ones of the terminals.

11. The connector of claim 2, wherein the cord-input cavity has approximately the same cross section as the cord with the walls of the cavity diverging continuously from the inner portion to the cord-input end of the connector and forming a flared inlet to avoid sharp bends in the cord during use thereof and to facilitate insertion of the leading end of the cord.

12. The electrical connector of claim 2, wherein the cord includes a jacket which encloses the individual conductors, the jacket being formed with a ridge longitudinally thereof, the cord-receiving cavity being formed with a groove parallel with the longitudinal axes of the troughs, the conductors of the cord inserted into the cavity being oriented properly with respect to associated ones of the troughs, the terminals and associated external contact elements only when the ridge is aligned with the groove.

13. The electrical connector of claim 2, at least the free end of which is insertable into a cavity of a jack wherein the housing is formed with a resilient locking tab cantilevered from the free end of the housing, the electrical connector inserted into the cavity being in engagement with a surface defining partially the jack cavity which is adjacent the surface of the housing to which the second contact portions of the terminals are exposed, the locking tab being depressed toward the housing at the free end thereof to insert the electrical connector into the jack cavity, the tab moving pivotally away from the housing when forces are no longer applied to depress the free end thereof, the movement of the tab tending to return the tab to an initial position and causing a surface thereof to engage an edge formed transversely of the jack cavity by surfaces defining partially the jack cavity.

14. The electrical connector of claim 13, wherein the tab is undercut at a portion thereof which engages the edge of the jack cavity, the undercut formed by a sloping surface which engages the edge, the configuration of the locking tab and the cooperative engagement thereof with the jack edge and at least one of the surfaces defining the edge being such that when the cord of the electrical connector is subjected to unintended forces in excess of a predetermined magnitude, the sloping surface of the tab will ride up over the edge to permit the electrical connector to be withdrawn from the jack cavity.

15. The electrical connector of claim 3, wherein the anchoring member is a conductor-restraining member which is capable of being moved to engage individual conductors of the cord to secure the conductors within the housing and prevent unintended lateral and longitudinal movement thereof.

16. An electrical connector for terminating a cord having a plurality of insulated conductors and for making electrical contact external to the connector, which comprises:

17. The electrical connector of claim 16, wherein the web of the anchoring member is formed so that the web is separated from the housing adjacent the housing to form an elongated extension which is caused to assume a curved shape as the anchoring member is moved pivotally to cause a blunt curved portion of the extension to engage the cord thereby preventing damage to the cord as forces are applied thereto during use of the cord.

18. The electrical connector of claim 16, wherein the cord includes a jacket which encloses the individual insulated conductors, and the anchoring member capable of being moved into engagement with a jacketed portion of the cord to anchor the jacket against unintended lateral and longitudinal movement.

19. The electrical connector of claim 16 wherein the anchoring member is formed within an opening in the housing that communicates with the cavity and the pivotal movement of the anchoring member causes the anchoring member to lock under one of the walls defining the opening to secure the anchoring member in engagement with the cord.

20. The electrical connector of claim 18, wherein the jacket is removed from a portion of the cord which is adjacent the free end of the housing and the at least one moveable portion of the housing also includes a conductor-restraining member formed integrally with the housing along at least a portion of the periphery of the conductor-restraining member such that compressive forces applied to the conductor-restraining member reforms the restraining member into a wedge-shaped element locked in engagement with the housing and the conductors to provide strain relief for the conductors during use of the cord.

21. A device for terminating a cord having a plurality of insulated conductors, which comprises:

22. A method of assembling a cord, which comprises individually insulated conductors enclosed in a jacket, to a device, which includes an unipartite housing constructed from a dielectric material having a cavity that opens to at least one end of the housing for receiving an end section of the cord, the surfaces of the housing defining the cavity substantially enclosing the entire end section of the cord, the housing also having conductor-receiving troughs formed in the cavity and terminal-receiving openings communicating with associated troughs, which includes the steps of:

23. The method of claim 22, wherein the step of applying forces to at least one portion includes:

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to electrical connecting devices for terminating cords and methods of assembling the devices to cords, and more particularly, to devices for making electrical connections between a cord comprising flexible conductors and terminals wherein conductive terminals are combined with one-piece dielectric members to form plugs and methods of assembling the cord and the devices.

2. Description of the Prior Art

In the telephone industry, increasing use is being made of modular plug type connectors on straight and retractile handset and line cords which are used between the base and a handset of a telephone and between the base and a wall terminal block. In the presently used plugs, a terminal is applied to each of a plurality of insulated conductors contained within a jacketed length of a retractile cordage. These terminals are mounted within a dielectric structure which is attached securely to the associated cordage. The dielectric portions of the plugs, which are mounted on both ends of a length of cordage, cooperate with receptacles in the handset and in the base of the telephone to properly align the terminals of the plug with mating terminals within the components of the telephone.

One presently used plug is disclosed in U.S. Pat. No. 3,699,498 issued on Oct. 17, 1972 in the names of E. C. Hardesty, C. L. Krumreich, A. E. Mulbarger, Jr. and S. W. Walden. In this disclosure, conductors are confined in conductor-receiving troughs formed in a dielectric base by a cover bonded to the base. Flat terminals are then inserted into individual grooves in the base in a side-by-side arrangement with contact portions thereof extending into engagement with the conductors. When the plug is inserted into a jack of a telephone handset, portions of the terminals in the jack engage portions of associated terminals in the plug.

Provisions in the just-identified plug for contacting the external component may be changed to that described in a continuation-in-part application Ser. No. 232,803 filed on Mar. 8, 1972 in the names of E. C. Hardesty, C. L. Krumreich, A. E. Mulbarger, Jr. and S. W. Walden. There, the external contact portions of the terminals of the plug consist of an edge exposed to the exterior of the dielectric enclosure.

Of course, the terminals in the plugs are aligned with the contact elements in the jack in the telephone handset. The cord conductors in the just described system are aligned with the terminals.

The recent trend to the use of plug-in type connectors in telephone handsets as exemplified by that shown in U.S. Pat. No. 3,617,982 has been accompanied by the use of flat telephone cords. The use of flat cords leads toward increased manufacturing economies provided that the plug is designed with regard for a flat cord system.

As an alternative to the bonding together of the portions of the dielectric housing in using the plug, it would be desirable to have a one-piece plug, into which a telephone cord end may be inserted and secured and subsequently engaged by flat terminals moved into terminal-receiving openings in the plug. Such a plug would also yield manufacturing economies.

SUMMARY OF THE INVENTION

This invention provides electrical connecting devices for terminating cords. A dielectric portion of the device can be fabricated in one-piece by using conventional molding techniques. The device may be assembled to a line cord or to a retractile cord either before or after the cord is heat treated to achieve retractile properties.

An electrical connecting device which embodies the principles of this invention is molded to include a one-piece or unipartite dielectric housing which includes a cavity that opens to at least one end of the housing for receiving an end section of a telephone cord. Unipartite or one-piece as used to describe the housing is intended to define the housing as not divided or divisible into parts. Moreover, the housing is molded so that no securing, including bonding, nor moving of hinged or otherwise moveable parts is necessary to form the cavity. The surfaces of the housing as molded define the cavity and substantially enclose the end portion of the cord. The plug is molded with a plurality of terminal-receiving openings communicating with the cavity and with the exterior of the connector. The housing is formed with at least one portion moveable at least partially into the cavity for engaging portions of the cord to secure the cord within the housing to prevent unintended movement of portions of the cord. Terminals positioned within associated ones of the terminal-receiving openings each includes a first contact portion extending into the cavity for making electrical engagement with the associated conductor in the cavity and a second contact portion positioned within the associated terminal-receiving opening for making electrical contact external to the connector.

A method embodying the principles of this invention for assembling connecting devices to cords for connecting electrically individual conductors which comprise the cord to associated components external to the device includes holding the housing and exposing individual insulated conductors of a predetermined length of a leading portion of the cord by removing the jacket therefrom. Then the leading portion of the cord is inserted into a cord-input aperture of the device and advanced to position the exposed conductors in conductor-receiving troughs. Forces are applied to portions formed integrally with the dielectric housing to move the portions to engage the jacket and the conductors to secure the cord within the device and provide strain relief for the jacket and the individual conductors. Terminals are inserted into openings in the device such that first contact portions extend into the troughs and pierce the insulation to establish an electrical connection with the conductors and to expose second contact portions of the terminals for engagement with external components.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features of the present invention will be readily understood from the following detailed description of specific embodiments thereof when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view showing plugs which embody the principles of this invention inserted into a handset and base portion of a telephone set and into a wall terminal;

FIG. 2 is a perspective view of one of the plugs prior to assembly of a cord and terminals therewith for purposes of clarity and further showing an internally movable jacket strain relief member of the plug prior to movement thereof;

FIG. 3 is a perspective view of the plug shown in FIG. 2 with terminals inserted into the plug and with the jacket strain relief member having been moved into engagement with the cord which has been inserted into the plug;

FIG. 4 is an elevational view of a housing of the plug partially in section prior to the assembly of the cord and terminals therewith;

FIG. 5 is an elevational view partially in section showing the jacket strain relief member of the plug after having been moved into engagement with the jacket of the cord to provide strain relief for the cord and a portion of the housing having been reformed into a strain relief member in engagement with the conductors and also showing the terminals inserted;

FIG. 6 is an elevational view showing an alternate embodiment in which one end of the plug housing is closed;

FIG. 7 is a front end view of the plug shown in FIG. 3 and taken along lines 7--7 thereof;

FIGS. 8 and 9 are enlarged detail views in elevation showing the use of tools to move the jacket strain relief member and to form the conductor strain relief member and with the tools and plug in an inverted position from that normally used for this operation;

FIG. 10 is an elevational view partially in section and showing the plug inserted into a jack in a telephone set;

FIG. 11 is an enlarged detail view of a portion of latching facilities of the plug in engagement with surfaces of a jack in the telephone set; and

FIG. 12 is a perspective view of an apparatus which may be used to carry out the steps of the methods of this invention.

DETAILED DESCRIPTION

1. Overall

Referring now to FIG. 1, there is shown a telephone, designated generally by the numeral 20, which includes a base portion, designated generally by the numeral 21, and a handset portion, designated generally by the numeral 22. A retractile cord, designated generally by the numeral 23, interconnects the base portion 21 and the handset portion 22.

Each end of the retractile cord 13 is provided with a plug, designated generally by the numeral 24, designed to be inserted into a jack 26. One of the plugs 24--24 is inserted into one of the jacks 26--26 assembled to the handset end and the other plug of the retractile cord 23 inserted into a jack in the base of the telephone 20. The plug 24 has facilities for establishing electrical connections between the cord 23 and internal contacting components 27--27 of the telephone 20 (see FIG. 10). Ones of the plugs 24--24 are also assembled to each end of a line cord, designated generally by the numeral 28 (see FIG. 1), for connecting the line cord to jacks 26--26 in the telephone base and in a wall terminal block 29.

Referring now to FIG. 5, a more detailed view of the structure of the retractile cord 23 can be seen. The retractile cord 23 includes a jacket 31 covering a plurality of insulated conductors 32--32. A free end portion of each of the conductors 32--32 is designed to be connected to an associated one of a plurality of terminals, designated generally by the numerals 33--33. Each of the conductors 32--32 is constructed of a nylon core 34 having a tinsel ribbon 36 wrapped helically thereabout. The tinsel ribbon 36 has a nylon insulation covering 37 extruded thereabout with a ridge 38 formed longitudinally thereof. The outside nominal diameter of the individual insulated conductors 32--32 is approximately 0.037 inch.

Miniature plugs constructed in accordance with the present inventions permit the expeditious connection of cord ends to the completed dielectric portion of the plugs rather than to a dielectric subassembly which must then be assembled to at least one other subassembly. This avoids having to maintain the cord 23 in a predetermined position in the subassembly while assembling the dielectric portion of the plug.

2. Dielectric Portion

The detailed construction of a plug 24 is shown in FIGS. 2, 4 and 7. A rigid, dielectric unpartite housing, designated generally by the numeral 40, is designed to be easily molded by using conventional injection molding techniques. The rigid, dielectric housing 40 has a free end 41, a cord-input end 42, and a terminal-receiving side 43 (see FIG. 4).

It may be observed from FIGS. 4 and 5 that the housing 40 is formed with a cord input aperture 44 which circumscribes substantially the portion of the jacket 31 of the cord 23 extending therethrough. As may be appreciated from the drawing, the housing 40 is constructed in one-piece with the cord input aperture 44 formed entirely therewithin. The aperture 44 has a flared entrance which prevents sharp bends in the cord 23 about an otherwise sharp edge during use of the telephone 10 by the subscriber. This advantageously increases the life of the cord 23. The flared entrance also facilitates insertion of a leading end of the cord 23.

The cord input aperture 44 opens to a cavity 46 (see FIG. 4) which partially terminates in a ledge 47 at the free end 41 of the base of the housing 40. The cavity 46 substantially encloses the entire end section of the cord which is inserted into the aperture 44 and is completely formed as molded. No further securing together of parts such as by bonding or moving of hinged parts with subsequent bonding together is required to form the cavity 46.

The formation of a one-piece housing 40 with the surfaces defining the cavity 46 substantially enclosing the entire end portion of the cord 23 facilitates holding the cord while other operations are performed by automated equipment. In prior art connectors, the cord 23 is generally positioned in a portion of a conductor-access opening formed in a base and then a lid bonded to the base. This, of course, will not suffice to hold the cord 23 in the base during assembly without additional steps and equipment. Moreover, problems have been experienced in consistently obtaining reliable bonds between the cover and the base.

As can best be seen in FIGS. 2 and 7, the cavity 46 is formed with a plurality of longitudinally extending partitions 48--48 which are molded with the dielectric housing 40. The partitions 48--48 are in the form of toothed ridges with a plurality of conductor-receiving troughs 49--49 formed therebetween on 0.040 inch centers and opening to the free end 41. The conductor-receiving troughs 49--49 are designed to receive associated ones of the conductors 32--32 (see FIG. 7). Each of the troughs 49--49 is dimensioned so that the conductor 32 therein cannot move laterally. This is necessary to insure that during the insertion of the terminals 33--33, the terminals remain aligned with the conductors 32--32 to make electrical engagement therewith.

It may be observed from FIG. 2 that the bottoms of the troughs 49--49 are substantially coplanar with the top surface of the ledge 47 at the free end 41. This facilitates the use of the ledge 47 at the free end 41 as an anvil for conductor cut-off during assembly of the plug 24 to the cord 23.

As can best be seen in FIG. 4, the portion of the cavity 46 adjacent the cord-input end 42 communicates with the main portions of the conductor-receiving troughs 49--49 through a tapered transition section 51 having a shoulder 52. The partitions 48--48 are constructed to extend along a sloping face 53 of the tapered transition section 51.

After the jacket 31 of the cord 23 is stripped therefrom to expose a predetermined length of each of the insulated conductors 32--32, the cord is inserted into the input aperture 44 until the conductors 32--32 are moved along associated ones of the conductor-receiving troughs 49--49 extending down the sloping face 53. The portions of the partitions extending down the sloping face 53 assist in guiding the conductors 32--32 into the main portions of the troughs 49--49. As the conductors 32--32 are moved up the face 53, the jacketed portion of the cord 23 is being moved into the cavity 46. When the cord 23 has been advanced such that the conductors 32--32 are received in the troughs 49--49, the leading end of the jacket 31 is in engagement with the shoulder 52 (see FIG. 5).

Also, as can be seen in FIG. 4, the walls of the cavity 46 are formed to include a groove 56 longitudinally thereof. The groove 56 is designed to mate with the ridge 38 formed externally of the jacket to insure that the cord 23 is inserted properly into the plug 24.

The housing 40 is also constructed with facilities for providing strain relief for the jacket and for the individual conductors 32--32. This is one of the key features of the invention in that it permits the use of a one-piece molded plug rather than two parts assembled to the cord 23. As can best be seen in FIG. 4, the housing 40 is constructed with an opening 59 having a jacket-anchoring member 61 connected to a rear section of the plug through a plastic hinge 62. Referring now to FIG. 2, it is seen that the member 61 extends for only a portion of the width of the housing 40. Moreover, the member 61 is connected at a forward end thereof by a very thin tapered web of dielectric material 63.

The configuration of the connecting web 63 is very important. As can best be seen in FIG. 4, the web 63 is constructed such that the dimension "d1," adjacent a forward wall 64 is substantially less than the dimension "d2 " adjacent the main body of the member 61. This has two functions. It insures that the web 63 is broken along the shearing plane along the dimension d1. The shearing plane is a vertical plane adjacent the wall 64 along the thinnest portion of the web 63. Secondly, the web 63 forms a rounded trailing edge (see FIG. 5) of the hinged member 61 to be formed and wrapped in a clockwise direction, as viewed in FIG. 5, of the cord 23. In this way, there are no sharp burrs or edges to tear the material comprising the jacket 31. Rather, the trailing end of the web 63 curls around, as seen in FIG. 5, with the contour of the cord 23.

The wrap-around effect of the web 63 permits the development of a more effective resistance of the cord 23 to forces imparted to the cord during customer use. If the member 61 were simply hinged initially without the web 63 and moved pivotally to engage the cord 23, the member would bite into the jacket 31. Then, during use, forces imparted to the cord 23 could cause a cutting of the jacket 31. However, the use of the web 63 which connects the member 61 initially to the portion 64 and then is severed, forms a blunt portion which engages the jacket 31 and avoids cutting into the jacket. This permits greater forces to be applied to the cord 23 without damaging the jacket 31.

The unitary dielectric housing 40 is also formed with facilities to provide strain relief for the conductors 32-32. An opening 66 extends transversely across a portion of the housing 40 (see FIG. 2). As can be seen in FIG. 4, a conductor-anchoring member in the form of a restraining bar 67 of dielectric material spans the opening 66. A portion of the conductor restraining bar 67 is spaced from the main portion of the housing 40 by slots 68 and 69 (see FIGS. 4 and 8). The restraining bar 67 is integral with the walls of the opening 66 through connecting portions 71 and 72. As can be seen in FIG. 2, the ends of the restraining bar 67 of dielectric material are spaced from the end walls of the opening 66.

In this way, an operator may cause a specially adapted tool 103 (see FIG. 8) to reform the restraining bar 67 within the opening 66 to provide a generally wedge-shaped strain relief element 70 (see FIGS. 5 and 9) in engagement with ones of the individual conductors 32--32. Forces are applied to the restraining bar 67 to shear the bar along irregular planes. The resultant strain relief element 70 is of a generally trapezoidal cross-section with the larger dimension base in engagement with the conductors 32--32. The sloping walls of the element 70 engage with the walls of the opening 66 to lock the element in engagement with the conductors 32--32.

While the embodiment shown in FIGS. 4 and 8, shows the pressure bar 67 separated from the housing 40 by he slots 68 and 69, it should be understood that other structural arrangements will suffice. For example, one of the slots 68 or 69, desirably the slot 69, may be extended to communicate with the cavity 46. Also, the restraining bar 67 may be molded so that forces applied thereto cause the bar to be moved linearly or pivotally to engage the conductors 32--32.

The use of the one-piece or unipartite dielectric housing 40 affords certain advantages. It permits an operator to simply insert a jacketed cord 23. Heretofore, separate or hinged portions (see application Ser. No. 311,575 filed Dec. 4, 1972 in the name of E. C. Hardesty) are mated together to secure the cord jacket and the conductors 32--32 within the assembled dielectric body. Finally, the terminals 33--33 are inserted into the assembled dielectric body.

In using a connecting device embodying the principles of this invention, there is no required bonding of mating portions with accompanying problems of alignment and reliability of the bond.

Moreover, the housing 40 has provisions molded therewith for securing the cord 23 to the plug and for alleviating strain relief on the cord jacket 28 and the conductors 32--32 during customer use. The jacket-anchoring member 61 and the conductor restraining bar 67 not only secure the plug 24 to the cord 23 but also provide strain relief for the jacket and the conductors, respectively.

After the cord 23 has been inserted into the aperture 44 and operator may apply forces to the member 61 to break the connection 63 and move the resulting tooth portion thereof into engagement with the cord jacket 31. As this is done, an upper portion 65 of the hinged member 61 catches under a ledge 73 (see FIGS. 5 and 9) which has been formed upon breaking the web 63. The strain relief for the individual conductors 32--32 is provided by reforming the dielectric restraining bar 67 downwardly within the opening 66 into the strain relief element 70 which engages with the individual conductors 32--32.

In this way, the terminals 33--33 function only to make electrical contact with the conductors 32--32 and are not required to retain the conductors and resist the forces imparted to the conductors or the cord during customer use. The forces on the conductors 32--32 occur notwithstanding the anchoring of the jacket 31 with the member 61. While the pressure on the jacket 31 may prevent the insulation 37 of the conductors 32--32 from moving relative to the jacket, the pressure is not sufficient to prevent the nylon core 34 and ribbon 36 from moving relative to the insulation thereof during customer use. This occurs because the relatively hard nylon insulation 37 forms what may be thought of as a tubulation over the core 34 and nylon 36 wrapped about the core. Forces applied to the cord 23 by the subscriber tends to cause the core 34 and ribbon to move slideably within the insulation 37. This movement, if unchecked, could cause the tinsel ribbon to be sheared off the core 34 at the engagement thereof with portions of the terminals 33--33.

The molding of the housing 40 with the ability to be able to precisely confine the conductors 32--32 in the troughs 49--49 is especially important. Prohibition against movement is necessary in order to cause the terminals 33--33 to penetrate the nylon-insulated conductors 32--32. The terminals 33--33 must be inserted with sufficiently high forces imparted thereto to penetrate the insulation. If the conductors 32--32 were free to move laterally of the plug, the terminals 33--33 may very well slice into the insulation on either side of the conductive elements and fail to establish engagement therewith.

As can best be seen in FIG. 2, the housing 40 is formed with a well 74 having a plurality of spaced parallel terminal-receiving openings 76--76 opening thereto. The openings 76--76 are in the form of slots and are aligned on a one-to-one basis with associated ones of the conductor-receiving troughs 49--49. Each of the terminal-receiving slots 76--76 is parallel to and communicates with an associated one of the conductor-receiving troughs 49--49. Each of the slots 76--76 is of a length slightly less than the out-to-out distance of that portion of the terminal 33 which is to be received therein. The shortening of the slots 76--76 from the overall length of the well 74 forms abutments 77--77 (see FIG. 4, for example).

The dielectric housing 40 is also formed with a plurality of fins 78--78 (see FIGS. 2, 3 and 7). The fins 78--78 are upstanding from a bottom surface 79 of the well 74 to which the terminal-receiving slots 76--76 open and are spaced apart approximately 0.035 inch. Also, the fins 78--78 are aligned between adjacent associated ones of the terminal-receiving slots 76--76. In this way, the external contacting components 27--27 of the jack 26 are received between the associated fins 78--78 and guided into engagement with portions of the terminals 33--33.

Formed integrally with the dielectric housing 40 is a resilient locking tab, designated generally by the numeral 80. The locking tab is approximately 0.040 inch thick, 0.200 inch wide, and 0.500 inch long. The locking tab 80 is molded so that its longitudinal axis is oriented at an angle approximately 15° with respect to the plane of the terminal-inserting side 43. The locking tab 80 is molded with a generally flat portion 81 connected by a plastic hinge 82 to the free end of the housing. The portion 81 is stepped to form wings 83--83 adjacent a subscriber-contact portion 84.

The combined height of the thickness of the locking tab 80 and resiliency of the locking tab permits the insertion of the plug 24 into the jack 26 between opposing surfaces 85 and 86 (see FIG. 10). The tab 80 can be deflected inwardly of the dielectric housing 40 to become substantially coplanar with the under-surface of the housing 40 and be moved slideably in engagement with the surface 85 which forms an entrance ledge (see FIG. 10).

After being released, the locking tab 80 will essentially resume its original molded shape and orientation because of its natural resilience. Proper resilience to provide desired flexing properties can be incorporated into the locking tab 80 when it is molded from polycarbonate or other appropriate materials with the aforementioned dimensions. Return of the tab 80 to its originally molded shape causes the free end of the tab to be urged downwardly into seating engagement with surfaces of the jack 26 (see FIGS. 10 and 11) in the handset 22 and base 21. A wall 87 and the ledge surface 85 cooperate to form an edge 88 which engages the locking tab 80. This locks the plug 24 to the jack 26 in the handset 22 and insures integrity of the connection during customer use.

The locking tab 80 is designed to permit the plug 24 to be released from the handset 22 when subjected to at least a predetermined force rather than to break the plug or rupture the cord 23. In order to accomplish this, the tab 80 is constructed with shallow angled shoulders 89--89 (see FIGS. 2 and 3) which form the wings 83--83. When the plug 24 has been inserted into the jack 26, the shoulders 89--89 engage the edge 88. The shoulders 89--89 ride up along the edge 88 when forces of a predetermined magnitude are imparted to the cord 23. Continued application of the forces cause withdrawal of the plug 24 from the jack 26.

3. Terminals

As can best be seen in FIG. 2, each one of the terminals 33--33 is made from an electrically conductive resilient material such as Phosphor bronze. The terminal 33 has a flat conductive portion 91 with at least one contact or insulation-piercing tang 92 protruding therefrom. The tangs 92--92 provide electrical connection between the conductive portion of the conductor 32--32 and the associated ones of the terminals 33--33.

Each of the blade-like terminals 33--33 also has an edge surface 93 having curved crowns 94--94 of predetermined radii. The crown 94 nearest the free end 41 of the housing 40 functions to complete the connection between the associated conductor 32 and an associated external-contacting component 27 illustrated in FIG. 10, and positioned in the telephone jack 26.

Provisions are also made for seating properly the terminals 33--33 within the associated terminal-receiving slots 76--76. Each of the terminals 33--33 is formed with shoulders 96--96 having necked-down portions 97--97 that terminate in barbs 98--98. As was indicated hereinbefore, the overall length of the terminal 33 out-to-out of the barbs 98--98 is greater than that of the length of the terminal-receiving slot 76. When the terminal 33 is inserted into the associated terminal-receiving slot 76, the barbs 98--98 penetrate the dielectric material which defines the slot to anchor the terminal (see FIG. 5).

The extent to which the terminal 33 is inserted into the associated slot 76 is determined by the operation of an apparatus, designated generally by the numeral 100 (see FIG. 12) used to insert the terminals. Generally, the apparatus 100 is controlled to insert the terminals 33--33 within the associated ones of the terminal-receiving slots 76--76 such that the shoulders 96--96 are spaced above the abutments 77--77.

The extent to which the terminal 33 is inserted into the associated terminal-receiving slot 76 is controlled to also insure that adequate electrical engagement is effected between the terminal tangs 92--92 and the conductors 32--32. If the depth of insertion is lacking, the tangs 92--92 may not engage one or both aligned portions of the helical tinsel ribbon 36. On the other hand if the depth of insertion is too great, the shoulders 98--98 could rupture the abutments 77--77. It is important that the tangs 92--92 engage the top or closest portion of the tinsel ribbon 36, be moved through the core 34, and into engagement with the bottom portion of the helically wrapped tinsel ribbon.

While the terminals 33--33 have been shown in a flat blade-like configuration, it should be obvious that they could be in the form of pins (not shown). Of course, the terminal-receiving openings 76--76 would then be molded to accommodate the pins (not shown) rather than the blade-like terminals 33--33.

ALTERNATE EMBODIMENT OF DIELECTRIC PORTION

There have been instances of contaminants and corrosive atmospheres penetrating the plug 74. This could cause problems in maintaining electrical continuity and reduction in the effectiveness of the electrical engagement between the terminals 33--33 and the cord 23.

In order to prevent such occurrences, the housing 40 of the plug may be modified to that designated 40A and shown in FIG. 6. The housing 40A is identical to the housing 40 except that the free end 41 has a wall 99 closing off the conductor-receiving troughs 49--49. This prevents any contaminants or unwanted atmospheric corrosives from entering the plug 24 at least from the one end thereof adjacent the terminals 33--33. This creates an essentially hemetic seal.

In using the plug 24 having a modified housing 40A, the cord 23 must be stripped of the jacket 31 with some precision to expose only a predetermined length of the conductors 32-32. Then, when the cord 23 is inserted into the cavity 46 and the free end of the jacket 31 abuts the shoulder 52, the ends of the conductors 32-32 will be spaced slightly from the wall 99.

SECOND ALTERNATE EMBODIMENT OF DIELECTRIC PORTION

It will be recalled that the embodiment first described herein discloses that the cord 23 have the jacket 31 removed from a leading portion thereof to expose the individual insulated conductors 32--32. The individual conductors 32--32 are received in the conductor-receiving troughs 49--49.

The principles of this invention may be used to construct a housing 40 which may accommodate an end portion of a flat cord 23 without the necessity of removing the jacket from an end portion thereof. The cavity 46 is molded without the conductor-receiving troughs 49--49 and such that a leading end portion of the cord 23 is inserted into the cavity. The cavity 46 is constructed to communicate with the terminal-receiving slots 76--76 and may or may not open to the free end 41 of the housing 40 (see FIG. 6).

In using this embodiment, the end portion of the cord 23 is inserted into the cavity 46. Then the terminals 33--33 are driven into the slots 76-76 into engagement with the conductive elements of the cord 23. Since the cord 23 is flat, and assuming that the cord is inserted properly into the cavity 46, the conductive elements of the cord are aligned properly with the terminals 33--33.

METHOD OF ASSEMBLING PLUG WITH CORD

The construction of the plug 24 is especially adapted to be used with flat cordage. Moreover, the plug 24 is easily adapted to automated high speed manufacturing. In describing the assembly of the plug 24 and the cord 23, reference will be made to FIGS. 4 and 5 which depict the steps of the method. Reference will also be made to FIG. 12 which illustrates the apparatus 100. The apparatus 100 is exemplary of apparatus which may be used to carry out the steps of the method.

One of the plugs 24--24 is positioned in a work holder 101. Then a leading end of the jacketed cord 23 has a portion of the jacket 31 stripped therefrom. The leading end of the cord 23 is inserted into the flared entrance 44 and into the cavity 46 with the conductors riding up along the sloped portion 53 until the conductors 32--32 are received in associated ones of the conductor-receiving troughs 49--49. At that time, the leading edge of the jacketed portion 31 engages the shoulder 52. Also, then, the conductors 32--32 extend onto and perhaps slightly past the ledge 47.

An advantage of constructing a one-piece dielectric housing 40 derives from the alignment feature of the cord 23 with the housing. In using prior plugs, it was necessary to align the conductors 32--32 with appropriate conductor-receiving facilities within the plug and to maintain that alignment during the insertion of the terminals 33--33. This is unnecessary in using the plug 24 embodying the features of this invention since the insertion of the cord 23 within the plug automatically maintains the cord therewithin and aligns the individual conductors 32--32 with the associated ones of the troughs 49--49.

There is still another significant advantage realized from the use of the one-piece plug 24. The dimensions of the separate dielectric portions in a two-piece plug may vary within tolerances as between different molding tools. This may cause problems of alignment as between successive matings of successive pairs of parts and further may cause problems of alignment of the terminals 33--33 and associated conductors 32--32 in assembly equipment when using parts from different molds. With the one-piece plug 24, the terminal-receiving slots 76--76 are inherently aligned with the conductor-receiving troughs 49--49.

Because the cord 23 is flat and because of the assembly process, the conductors 32--32 are spaced in a prearranged order in the troughs 49--49. Once the cord 23 is inserted into the housing 40 in the correct orientation, then it is unnecessary for an operator to identify the conductors 32--32 prior to the electrical connection with ones of the terminals 33--33. The order in the cord 13 is maintained in the plug 24 to correspond to the order of engagement with the external contact elements 27--27.

However, to insure the correct orientation of the cord 23 with respect to the plug 24, the cord must be inserted into the plug in such a fashion to insure that the order of the conductors 32--32 is correct. Since the cavity 46 is formed with the groove 56, the cord 23 should be inserted such that the ridge 38 on the cord jacket 31 is received in the groove. If the cord 23 were inserted in an inverted position, the conductors 32--32 would not be oriented properly with the terminals 33--33 and hence with the external contacting components 27--27. Also, the subsequent engagement of the member 61 with the cord 23 would span the ridge and not be fully seated across the jacket enclosing the four conductors 32--32. This would result in a less efficient anchoring of the jacket 31.

The operator then causes a tool 102 to be moved into engagement with the member 61 to break the thin web 63. The now-hinged member 61 is moved counterclockwise, as viewed in FIG. 5, until the toothed portion 65 thereof catches and locks under the newly formed ledge 73. As can be seen in FIGS. 5 and 9 the thin web 63 is such that the free end thereof curls around to form a blunt portion which engages the cord jacket 31.

Next, the operator causes the tool 103 to engage the conductor-restraining bar 67 within the opening 66 (see FIG. 8) and apply compressive forces thereto. The conductor bar 67 is reformed and broken off along the lines shown dotted in FIG. 9 into the tapered or wedge-shaped dielectric element 70 (see FIG. 9) and moved into engagement with the conductors 32--32. The element 70 spans the conductors 32--32 with the bottom portion thereof tending to assume the partial peripheral shape along the tops of the conductors 32--32. Moreover, the element 70 is locked in the position shown in FIG. 9. The element 70 therefore locks the conductors in the troughs 49-49 to provide strain relief for the conductors while the toothed portion of the hinged member 61, i.e., the web 63, provides strain relief for the jacket 31.

The tool 103 used to reform the body 67 spans the entire opening 66. This is unlike the tool 102 which is used to move the member 61. In this way, downward movement of the tool 103 does not cause the restraining bar 67 to be moved pivotally about one of the connecting portions 71 and 72. Rather, as shown in FIG. 9, the restraining bar 67 is moved downwardly beginning at the bottom of the slots 68 and 69 and mushrooms outwardly. This in effect forms the strain relief element 70 having a generally trapezoidal cross-section which is locked at the bottom of the opening 66 in tight engagement with the conductors 32--32.

Then the free end portions of the conductor 32--32 are trimmed off with a cutting device 104 using the ledge 47 as a bearing surface. The extension of the leading ends of the conductors 32--32 onto the ledge 47 avoids having to strip exactly the leading ends of the conductors.

In the alternative embodiment shown in FIG. 6 with the troughs 49--49 not opening to the ledge 47, the conductors 32--32 are presized to approach the ends of the troughs. The cut-off must be such that the conductors extend beyond the most forward one of the tangs 92--92. The construction of the plug 24 with a closed front end minimizes moisture absorption and exposure of the terminals 33--33 to a corrosive atmosphere. This creates an effective hemetic seal.

In order to complete the assembly of the plug 24 to an end of the cord 23, four of the terminals 33--33 are inserted into the plug. The blade-like terminals 33--33 are inserted by rams 106--106 from the terminal-receiving face 43 of the plug 24 into associated ones of the terminal-receiving slots 76--76 until the rams bottom out. The shoulders 96-96 thereof are spaced above the abutments 77--77 (see FIG. 5). At that time, the contact tangs 92--92 extend into the associated trough 49--49. The tangs 92--92 penetrate the insulation of the conductors 32--32 confined in the troughs 49-49 and establish electrical contact with both the upper and lower wraps, as viewed in FIG. 5, of the tinsel ribbon 36. Also, the barbs 93--98 are caused to become embedded in the portion of the dielectric housing 40 which defines the terminal-receiving slot 76--76. This anchors the terminal 33--33 against movement or inadvertent removal from the housing 40.

An apparatus for completing the formation of and inserting the terminals 33--33 into housing 40 is disclosed and claimed in application Ser. No. 346,556 filed on Mar. 30, 1973 in the names of W. B. Brown (deceased) and F. D. Gavin.

Of course, apparatus other than the apparatus 100 may be used to practice the methods of this invention. For example the assembly of the plug 24 to the cord 23 could be accomplished by using a turntable, (not shown) with facilities for inserting the cord, stripping the cord, etc. arranged about the periphery of the turntable. Successive cords 23--23 and associated plugs 24--24 are moved with the turntable (not shown) through the work stations.

It is to be understood that the above described arrangements are simply illustrative of the invention. Other arrangements may be devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.