US3272913A

US3272913A - Two-wire socket insulator

Info

Publication number: US3272913A
Application number: US352779A
Authority: US
Inventors: David J Crimmins; Robert W Croghan
Original assignee: Thomas and Betts Corp
Current assignee: ABB Installation Products Inc
Priority date: 1964-03-18
Filing date: 1964-03-18
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

p 13, 1966 D. J. CRIMMINS ETAL 3, 7 ,9 3

TWO-WIRE SOCKET INSULATOR 2 Sheets-Sheet 1 Filed March 1.8; 1964 W s WW W W9C M A 5, DZ M8 QWM Ab 21 :9 1a 20 22 Sept 1966 D. J. CRIMMINS ETAL 3,272,913

TWOWIRE SOCKET INSULATOR 2 Sheets-Sheet 2 Filed March i8, 1964 6 mg mw l d Q I M d 0 w m United States Patent 3,272,913 TWO-WIRE SOCKET INSULATOR David J. Crimmins, Pennington, and Robert W. Croghan, Belle Mead, N.J., assignors to The Thomas & Betts Co., Inc., Elizabeth, N.J., a corporation of New Jersey Filed Mar. 18, 1964, Ser. No. 352,779 7 Claims. (Cl. 174-138) This invention relates to an insulator for an electrical connecting device and more in particular to an insulator which can be opened to receive an electrically conductive element and to be closed about the element in order to retain it.

Insulators are commonly employed in an electrical connecting device in order to support and insulate the electrically conductive elements of the device, such as wires and terminals, with respect to one another and the other portions of the connecting device. For example, in a connecting device such as a socket adapted to receive a bayonet-type lamp having two contacts at its base, the socket includes a shell member containing an insulator through which a pair of lead wires extend in alignment with the contacts of the lamp. In many cases the ends of the lead wires protruding from the insulator are provided with rivets or terminals adapted to engage the contacts at the base of the lamp. In conventional sockets the insulator is formed of one piece of insulating material such -as plastic or ceramic material. In forming the conventional insulator, openings or holes are provided in order to receive the lead wires and to position and insulate them from one another.

In assembling the conventional socket, the need to insert the lead wires through the insulator openings and the degree of alignment required prevents the use of high speed or automatic assembly procedures. Thus each of the lead wires must be carefully inserted and positioned Within the openings in the insulator. Where rivets or terminals are applied to the free ends of the lead wires, the lead wires must be first passed through the openings in the insulator and then the rivets or terminals applied to the free ends of the wires. If the rivets or terminals of the lead wires are applied by automatic machines before the lead wires are inserted in the insulator, then it may be necessary to pass the entire length of lead wire through the insulator since normally the rivet or terminal is designed to engage the insulator and consequently cannot pass through its opening. Thus heretofore, due to the one-piece insulator construction, automatic assembly of lead wires to socket insulators has been prevented.

It is therefore one of the objects of the invention to provide an insulator for an electrical connecting device which can be assembled with a conductive element by automatic means.

It is another object of the invention to provide an insulator which is adapted to be opened to receive an electrically conductive element and subsequently to be closed to retain it.

It is still another object of the invention to provide an insulator which can be locked after being closed about an electrically conductive element.

It is an additional object of the invention to provide an insulator for an electrical connecting device which is adapted to guide the lead wires thereof into their proper position during assembly.

It is also an addition-a1 object of the invention to provide an insulator which is adapted to be opened to receive a lead wire and to be closed about the lead wire in order to maintain it in an operative position and to prevent it from being withdrawn from the insulator.

It is a further object of the invention to provide an insulator which is adapted to be opened to receive a terminal and to engage the terminal as the insulator is closed about it.

It is also a further object of the invention to provide a method for the automatic assembly of lead wires with an insulator.

In one of the embodiments of the invention, the insulator for an electrically conductive element comprises a pair of support members which are articulated in a facing relationship with one another. Each of the support members is provided with a grooved portion disposed in a facing relationship with one another. At least one of the grooved portions is adapted to receive the conductive element when the support members are positioned away from one another. The support members are adapted to retain the electrically conductive element within the grooved portion of each when the support members are positioned adjacent to one another.

In another embodiment of the invention means are provided for securing the support members adjacent to one another in a closed position.

In still another embodiment of the invention the insulator includes an abutment member and a pair of support members pivotally attached to the abutment member adjacent to a different one of the sides thereof. When the support members are positioned apart from the abutment member, the conductive elements can be received therebetween and when the support members are positioned adjacent to the abutment member, the conductive elements are adapted to be retained therebetween.

In yet still another embodiment of the invention the support members and abutment members are provided with guide portions adjacent to and inclined toward the grooved portions therein in order to direct the electrically conductive element toward the grooved portions during assembly.

In an additional embodiment of the invention a web extending between the support members serves as the means for pivotally attaching them to one another.

In a further embodiment of the invention the grooved portions of the insulator are provided with means for engaging the electrically conductive element disposed therebetween.

In still a further embodiment of the invention the insulator is adapted to engage the terminal to maintain it in a predetermined position.

Other objects and features of the invention will become apparent in the following specification and claims and in the drawings in which:

FIG. 1 is a perspective view of the insulator of the invention showing it in the closed position retaining the lead wires;

FIG. 2 is a vertical section view of a lamp socket containing the insulator of the invention;

FIG. 3 is a perspective view of the insulator of the invention in the opened position thereof both prior and during the installation of the lead wires therein in accordance with the method of the invention;

FIG. 4 is an elevational view of the insulator in the opened position showing its guide portions and lock member;

FIG. 5 is an elevational view of the insulator showing it in the closed position retaining the lead wires;

FIG. 6 is a perspective view of the insulator of the invention in its fully opened position showing the ribs within the grooved portion thereof for engaging the electrically conductive element;

FIG. 7 is an end view of the fully opened insulator showing the access provided for the insertion of the electrically conductive elements;

FIG. 8 is a vertical section view of the insulator showing the lead wires adjacent to the ribs in the grooved portions prior to the closing of the insulator;

'ture adjacent to the insulator.

FIG. 9 is a vertical section view showing the insulator in its closed position in which the ribs in the grooved portion are mechanically engaged with the lead wires; and

FIG. 10 is a fragmentary vertical section view showing a lug in the grooved portion of the insulator in engagement with an opening in the terminal of the lead wire.

Insulator 10 of the'invention (FIG. 1) is adapted to receive a pair of.

lead wires

11 and 12 in order to support and insulate them from one another as well as any struc- The insulator includes abutment member or separator 13 which is for-med with grooved portions or grooves 14 on each of the opposite sides thereof (FIG. 4). Separator 13 is supported by tongue 15 attached thereto. Support members or supports 16 and 17 are positioned at the opposite sides of separator 13 and are pivotally attached or articulated to one another by web 18 from which extends tongue 15 of the separator.

The outer surfaces 17a and 18a of

supports

16 and 17, respectively are provided with chamfers 19 and 20, respectively, in order to provide a gradual reduction in thickness of

ends

21 and 22 adjacent to web 18. Insulator 10 can be fabricated from plastic material having good insulating characteristics such as nylon. Where plastic material of the thermoplastic type is employed, the insulator can be conveniently and economically manufactured by injection molding. Plastic material such as nylon is flexible in thin sections and therefore web 18 can serve as a pivot or hinge connection between the supports. Similarly the thin section of tongue 15 enables it to flexibly support separator 13. In heavier sections plastic material such as nylon is substantially rigid and capable of maintaining dimensional accuracy. Thus support 16 and support 17 as well as separator 13 are enabled to maintain their form after molding.

Groovedportions or

openings

23 and 24 of

supports

16 and 17, respectively, are adapted to receive the lead wires. Where

lead wires

11 and 12 are provided with terminals or

rivets

25 and 26, respectively, supports 16 and 17 are provided with

chamfers

23a and 24a, respectively, adjacent to the openings. The chamfers serve as seats for the terminals (FIG. 2). In order to facilitate the placement of the lead wires into

openings

23 and 24, supports 16 and 17, are provided with guide portions or

inclined surfaces

27 and 28, respectively, which slope toward the openings. In the closed position of the insulator as shown in FIG. 5, the inclined surfaces of the supports are substantially contiguous with

inclined surfaces

29 and 30 of the separator. Inclined surfaces 29 of the separator also serve as guides for directing the lead wires toward their respective openings in the supports during installation of the lead wires.

The means for securing the support members adjacent to one another and the separator in the closed position in order to retain the lead wires includes hook 31 extending from support 17. Upon the closure of the insulator about the lead wires, hook 31 at its cam portion 32 engages ramp 33 and is deflected outwardly as a result of the flexibility of the hook formed from plastic material. Upon further closing of the insulator, the hook passes beyond ridge 33a of the ramp and drops into slot 34. Shoulder 35 adjacent to slot 34 and shoulder 36 adjacent to ramp 33 serve to cage and hold hook 31 in its locked position. With this arrangement the insulator becomes self-locking whenever the supports are urged into the closed position.

As shown in FIG. 2, the insulator of the invention can be employed with an electrical connecting device such as socket 37 which is adapted to receive a connector of the bayonet-type such as the bayonet-base of a lamp.

Thus slot 38 of the socket is adapted to engage and secure one of the studs extending laterally from the base of the lamp. Insulator 10 of the invention is adapted to be installed within shell 39 of the socket;

Sides

40 and 41 of supports 17 and 18 are arcuate in form in order to fit snugly within the cylindrical internal surface of the shell.

In order to maintain

terminals

25 and 26 of the lead wires in close contact with the terminals of the connector or lamp base to be engaged therewith, the insulator and consequently the terminals are urged upwardly by spring 42 which is disposed within the shell and bears upon change 43 adjacent to the base of the socket.

Supports

16 and 17 are relieved at the ends thereof opposite to the location of the beads to form shouldered

portions

44 and 45, respectively. The shouldered portions engage and pilot the spring with respect to the insulator. In order to insure polarity of the lead wires with respect to the lamp base, insulator 10 is provided with key 46 extending from side 40 of support 17. The key extends into slot 47 in shell 39, thereby maintaining a predetermined position of the insulator with respect to the shell while enabling the insulator to move in the longitudinal direction of the shell during installation of the lamp.

Insulator 48 is shown in its fully opened position in FIG. 6. Insulator 48 which substantially corresponds to insulator 10 is provided with means for engaging the electrically conductive element, that is

ribs

49 and 50 disposed in a circumferential manner in

openings

51 and 52, respectively. The engaging means further includes ribs '53 extending along each of grooves 54 of separator 55. As shown in FIG. 8 lead wires 56 and 57 which are to be inserted into insulator 48 are provided with

terminals

58 and 59, respectively, connected to conductors 56a and 57a, respectively. The terminals have barrels 58a and 59a of the diagonal wrap-type which are formed about the conductors of the lead Wires.

With insulator 48 in the fully opened position as shown in FIGS. 6 and 7, the lead wires with their terminals in place can be dropped into

openings

51 and 52, whereupon insulation 56b and 57b of the lead wires engages the ribs in the openings of the insulator as shown in FIG. 8. With the lead wires resting in the openings of the insulators and with the terminals positioned adjacent to end portion 60 of the insulator, the insulator is ready to be closed about the lead wires. During the closing operation, supports 61 and 62 of the insulator in which are formed

openings

51 and 52, respectively, are moved toward separator 55. As this occurs the ribs within the openings and the ribs of the separator grooves engage and deform the insulation of the lead wires as shown in FIG. 9. The engagement of the ribs mechanically locks the insulation and the conductors therein with respect to the insulator so that upon the application of tension to the lead wires, the force is transmitted to the insulator directly and not by way of the terminals. Thus any tendency for the terminals to be moved or loosened with respect to the conductors is eliminated. When the insulator is fully closed about the lead wires, hook 63 (FIG. 6) locks insulator 48 in the closed position similarly as discussed wit-h respect to insulator 10. Thus the hook can maintain the insulator closed even though the compression of the insulator by the ribs results in the application of opening forces to the supports of the insulator.

In certain applications it is desirable to prevent rotation of the terminal with respect to the insulator when the parts are in their operative position. As shown in FIG. 10 insulator 6 4 which is similar to insulator 10 includes support 65 having lug 66 formed in opening 67 adjacent to end portion 68 of the insulator. The terminal to be used with insulator 64, that is terminal 69, includes head portion 70, barrel portion 71 and sleeve portion 72. The barrel portion is formed into engagement with conductors 73 and lead wire 74 while sleeve portion 72 is formed into engagement with insulation 75 of the lead wire.

During assembly as support 65 is closed toward separator 76, lug 66 enters into slot or opening 77 formed between head portion and barrel portion7'1. At the same time shoulder 78 is advanced adjacent to barrel portion 71 and sleeve portion 72. In this way terminal 69 is keyed into a predetermined position with respect to insulator 64. Engagement of the insulator to the terminal in this fashion can be conveniently accomplished as the insulator is closed about the terminal. Such an engagement would be impossible to achieve except by means of the insulator of the invention since normally the openings of an insulator must be free of lugs or shoulders to enable the lead wires to be fed through the openings prior to the attachment thereto of the terminals.

In accordance with the method of the invention prior to the assembly of the lead wires with the insulator, the insulator is placed in an open position in which the supports are spread apart from one another and the separator, at least to the extent shown in FIGS. 3 and 4. Thus due to the flexible nature of web 18 the supports can be spread apart over a range of opened positions extending to a position where outside surfaces 40 and 41 adjacent to ends 20 and 21, respectively, are substantially tangential with one another. Insulator 48 is shown in the fully opened position in FIG. 7. At this position, the insulator is urged into an approximate T-shape so that

inclined surfaces

27 and 28 face in substantially the same direction.

In automatic assembly of the lead wires with the insulator, the insulators are spread open and secured in the open position by means not shown. Thus once the insulator is opened, guide rails or the like can engage the supports of the insulator and maintain the insulator in an opened position until it reaches a station at which the lead wires are to be placed in or urged into the open- .ings of the supports. Thus as shown in FIG. 3, the steps of assembly in accordance with the method of the invention include the opening of the insulator, followed by the delivery thereto of the lead wires. It can be understood that the lead wires can be delivered to the .insulator in a rapid manner since inclined surfaces 29 of the separator and

inclined surfaces

27 and 23 of the supports guide the lead wires toward the openings in the supports. This is true whether the portion of the lead wires to be inserted in the openings of the insulator are completely or partially stripped of insulation. Furthermore, the presence of rivets or terminals at the ends of the lead wires in no way interferes with the delivery of them into the openings. :In this way the insulator and the method of the invention make it possible to assemble insulators and lead wires in an automatic manner.

With the lead wires positioned within the supports of the insulator as shown in FIG. 3, the final step of assembly is the closure of the supports about the lead wires. During closing, as the supports approach to a position adjacent to the separator, cam portion 32 of book 31 passes along ramp 33 and at the final closed position of the insulator, the hook drops into slot 34 and is locked.

Shoulders

35 and 36 adjacent to the hook cage it in the locked position. In the

closed position openings

23 and 24, in conjunction with grooves 14 in the separator, form substantially cylindrical holes which extend through the insulator and serve to retain the lead wires in position with respect thereto.

By virtue of the self-locking action of hook 31 the assembled insulator and lead wires is secured in a closed position which is suited for subsequent automatic assembly operations related to the insulation of the insulator and lead wires into shell 39 of socket 37. During this assembly operation, key 46 of the insulator is engaged with slot 47 in the shell to insure the proper polarity of the lead wires with respect to the socket.

It is to be appreciated that the embodiments described herein are merely intended to be illustrative of the present invention and that variations may be made thereon by one skilled in the art without departing from the spirit and the scope of this invention.

What is claimed is:

1. An insulator for a pair of electrically conductive elements comprising an abutment member, a pair of support members, each of said pair of support members being pivotally attached to said abutment member adjacent to one end portion thereof and facing a different one of the opposite sides thereof and having a grooved portion in a facing relationship with one another, each of said support members having a guide portion adjacent each side of said grooved portion therein and inclined thereto, said guide portions of each of said support members being adapted to direct said electrically conductive element into said grooved portion adjacent thereto, each of said support members when positioned spaced apart from said abutment member being adapted to receive a conductive element between said support member and said abutment member into said grooved portion and when positioned contiguous with a different one of the opposite sides of said abutment member to retain said conducting element between said support member and said abutment member in said grooved portion.

2. An insulator for a pair of electrically conductive elements comprising an abutment member having a pair of oppositely disposed sides each having a grooved portion disposed therein, the portions of said abutment member adjacent said grooved portion therein sloping therefrom, said sloping portions being disposed at a predetermined angle to one another, and a pair of support members, each of said support members being pivotally attached to a different one of the opposite sides of said abutment member and having an additional grooved portion in a facing relationship with the relieved portion in the side of said abutment member adjacent thereto, each of said support members having a guide portion adjacent each side of said additional grooved portion therein and inclined thereto, said guide portions being adapted to direct said electrically conductive element into said grooved portion adjacent thereto, said guide portions of each of said support members being disposed at an angle with respect to one another which is complementary to said predetermined angle, each support member and said abutment member when positioned apart from one another being adapted to receive a conductive element therebetween and when positioned in engagement with one another being adapted to retain said conductive element therebetween.

3. In an electrical socket device having a shell member for receiving a pair of conductive elements, the combination comprising an insulator disposed in said shell member, said insulator including an abutment member having a pair of oppositely disposed sides each having a relieved portion disposed therein, a pair of support members, each of said support members being pivotally attached to a different one of the opposite sides of said abutment member and having an additional relieved portion in a facing relationship with the relieved portion in the side of said abutment member adjacent thereto, each support member and said abutment member positioned apart from one another to receive a conductive element therebetween and when positioned adjacent one another retaining said conductive element therebetween, and means extending from one support and engaging the other support member for securing said support members adjacent one another in response to the moving of said support members together.

4. An insulator for a pair of electrical terminal elements each attached to a different electrical lead wire, each of said terminals having a relieved portion therein, said insulator comprising an abutment member having a grooved portion in each of the opposite sides thereof, a pair of support members, each of said pair of support members being pivotally attached to said abutment member adjacent to a different one of said opposite sides thereof and having an additional grooved portion in a facing relationship with one another, at least one of each of said grooved portions and said additional grooved portion adjacent thereto having a keying element disposed therein,

each of said support members having a guide portion adjacent each side of said additional grooved portion therein and inclined thereto, said guide portion being adapted to direct a different one of said electrical terminal elements when adjacent thereto into said grooved portion, each of said support members when positioned spaced apart from said abutment member being adapted to receive a different one of said electrical terminal elements between said support member and said abutment member into said grooved portion and when positioned adjacent said abutment member to retain said electrical terminal element between said support member and said abutment member in said grooved portion, said keying element engaging the relieved portion of said electrical terminal element adjacent thereto when said support members are positioned adjacent said abutment member.

5. An insulator for a pair of electrically conductive elements comprising an abutment member having a pair of oppositely disposed sides each intersected by a relieved portion disposed therein, said relieved portions dividing each of said sides into two surfaces, and a pair of support members, each of said support members being pivotally attached to one end portion thereof and facing a different one of the opposite sides of said abutment member and being intersected by an additional relieved portion in a facing relationship with the relieved portion in the side of said abutment member adjacent thereto, each of said additional relieved portions dividing said support member into two additional surfaces, each support member when positioned apart from said abutment member being adapted to receive a conductive element therebetween and when positioned with said additional surfaces contiguous with said surfaces of said abutment member being adapted to retain said conductive element thereebtween.

6. An insulator for a pair of electrically conductive elements comprising an abutment member having a pair of oppositely disposed sides each intersected by a relieved portion disposed therein, said relieved portions dividing each of said sides into two surfaces, a pair of support members, each of said support members being pivotally attached to one end portion thereof and facing a different one of the opposite sides of said abutment member and being intersected by an additional relieved portion in a facing relationship with the relieved portion in the side of said abutment member adjacent thereto, each of said additional relieved portions dividing said support member into two additional surfaces, each supo rt member when positioned apart from said abutment member being adapted to receive a conductive element therebetween and when positioned contiguous with a different one of the opposite sides of said abutment member with said additional surface contiguous with said surfaces of said abutment member being adapted to retain said conductive element therebetween, and means extending between said support members for securing them together when positioned adjacent one another.

7. An insulator for a pair of electrical terminal elements each attached to a different electrical lead wire, said insulator comprising an abutment member having a grooved portion in each of the opposite sides thereof, the surfaces of one of said opposite sides of said abutment member extending away from adjacent said grooved portion therein at a predetermined included angle with respect to one another and converging toward the corresponding surfaces of the other of said opposite sides of said abutment member, a pair of support members each of said pair of support members being pivotally attached to said abutment member adjacent to a different one of said opposite sides thereof and having an additional grooved portion in a substantially facing relationship with said grooved portion adjacent thereto, at least one of each of said grooved portions and said additional grooved portion adjacent thereto having a rib element disposed therein, each of said support members having a guide portion adjacent each side of said additional grooved portion therein and inclined thereto, the angle between the surfaces of said guide portions corresponding to said predetermined included angle to enable each of said support members to mate with said abutment member, said guide portion being adapted to direct a different one of said electrical terminal elements when adjacent thereto into said grooved portion, each of said support members when positioned spaced apart from said abutment member being adapted to receive a different one of said electrical terminal elements and said lead wire attached thereto between said support member and said abutment member into said grooved portion and when positioned adjacent said abutment member being adapted to retain said electrical terminal element and said lead wire attached thereto between said support member and said abutment member in said grooved portion as said surfaces of said guide portions engage said surfaces of said side of said abutment member adjacent thereto, said rib element engaging said lead wire adjacent thereto when said support members are positioned adjacent said abutment member.

References Cited by the Examiner UNITED STATES PATENTS 2,100,025 11/1937 Douglas 339-188 X 2,563,604- 8/1951 Hultgren 174153 2,639,312 5/1953 Kerwin 17488 X 2,727,089 12/1955 Cuccaro 174164 3,056,852 10/1962 Sachs 174l53 3,057,001 10/1962 Rapata 174--153 X 3,126,184 3/1964 Kropp 174164 X 3,127,471 3/1964 Greiner 174-155 X FOREIGN PATENTS 265,739 2/ 1927 Great Britain. 863,386 .3/1961 Great Britain.

LARAMIE E. ASKIN, Primary Examiner.

Claims

5. AN INSULATOR FOR A PAIR OF ELECTRICALLY CONDUCTIVE ELEMENTS COMPRISING AN ABUTMENT MEMBER HAVING A PAIR OF OPPOSITELY DISPOSED THEREIN, SAID RELIEVED PORTION DISPOSED THEREIN, SAID RELIEVED PORTIONS DIVIDING EACH OF SAID SIDES INTO TWO SURFACES, AND A PAIR OF SUPPORT MEMBERS, EACH OF SAID SUPPORT MEMBERS BEING PIVOTALLY ATTACHED TO ONE END PORTION THEREOF AND FACING A DIFFERENT ONE OF THE OPPOSITE SIDES OF SAID ABUTMENT MEMBER AND BEING INTERSECTED BY AN ADDITIONAL RELIEVED PORTION IN A FACING RELATIONSHIP WITH THE RELIVED PORTION IN A OF SAID ABUTMENT MEMBER ADJACENT THERETO, EACH OF SAID ADDITIONAL RELEIVED PORTIONS DIVIDING SAID SUPPORT MEMBER INTO TWO ADDITIONAL SURFACES, EACH SUPPORT MEMBER WHEN POSITIONED APART FROM SAID ABUTMENT MEMBER BEING ADAPTED TO RECEIVE A CONDUCTIVE ELEMENT THEREBETWEEN AND WHEN POSITIONED WITH SAID ADDITIONAL SURFACES CONTIGUOUS WITH SAID SURFACES OF SAID ABUTMENT MEMBER BEING ADAPTED TO RETAIN SAID CONDUCTIVE ELEMENT THEREBETWEEN.