US3474394A

US3474394A - Means for making electrical connections

Info

Publication number: US3474394A
Application number: US644666A
Authority: US
Inventors: Kemper Martel Hammell; Robert Franklin Cobaugh
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1964-12-23
Filing date: 1967-06-08
Publication date: 1969-10-21
Anticipated expiration: 1986-10-21
Also published as: US3325770A; DE1465238B2; DE1465238A1; NL139848B; NL6515872A; GB1081180A

Description

brlginal Filed Dec. 23, 1964 T \igg.

- 'K. M. 'HAMMELL ETAI- 3,474,394-

I MEANS FOR MAKING ELECTRICAL CONNECTIONS 3 Sheets-Sheet 1 ae U @2 F m I an a! 40 30 I FTI Oct; 21, 1969 K-.M. HAMMELL ETAL 3 474 4 MEANS FOR MAKING ELECTRICAL CONNECTIONS Zriginal med Dec. 23, 1964 s Sheets-Sheet :2

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BY Paeezr fknmtuu Camus Oct. 21, 1969 KM HAMMELL ET AL 3,474,394 MEANS FOR MAKING ELECTRICAL CONNECTIONS Original Filed Dec 23, 1964 5 Sheets-Sheet 3 INVENTORS (EMPEQ IYmem #qpmeu eoaeer fEHA/LUN Camus/ 3,474,394 MEANS FDR MAKING ELECTRK'CAL CGNNECTIONS Kemper Martel Hammell, Harrisburg, and Robert Franklin Cohaugh, Hershey, Pa., assignors to AMP Incorporated, Harrisburg, Pa.

@riginal application Dec. 23, 1%4, Ser. No. 420,666, new Patent No. 3,325,770, dated June 13, 1967. Divided and this application June 8, 1967, Ser. No. 644,666 The portion of the term of the patent subsequent to June 13, 1984, has been disclaimed int. Cl. Hllr 33/ 88 US. Cl. 339-176 6 Claims ABSTRACT 0F THE DISCLOSURE An electrical connector constitutes a dielectric housing and an electrical terminal provided with a forked contact. The housing contains a passageway extending therethrough including an entrance through which a post enters and is disposed therewithin. The passageway also includes section means for bearing on opposite sides of the post to stabilize the housing on the post in one direction and the section means define centering means to center the forked contact for engagement on other opposite sides of the post. Means are provided on the forked contact and in the passageway to guide the forked contact toward the section means and to maintain the forked contact in a predetermined position in the passageway.

CROSS-REFERENCE TO RELATED APPLICATION This application is a division of US. patent application Ser. No. 420,666, filed Dec. 23, 1964, now Patent No. 3,325,770, issued June 13, 1967.

SPECIFICATION This invention relates to disengageable electrical connectors for connecting conductors to terminal posts on a panelboard.

An object of the invention is to provide an improved electrical single or multiple disconnect for connecting conductors to square or rectangular-sectioned terminal posts on a panelboard or mounting means. A further object is to provide a connecting device for connecting relatively large conductors to relatively small terminal posts which are mounted on a panelboard. A still further object is to provide a connector for connecting at least two external conductors to a relatively small terminal post where only a relatively short length of the post is available for making electrical connections with the external conductors. An additional object is to provide a housing of dielectric material which is cooperable with a terminal post and with fork-type terminals in the housing so as to provide axial stability in two planes and stability against rotation of the housing on the post. A still further object is to provide a connecting device which is particularly intended for usage where the spacing between terminal posts and terminal panels are limited.

These and other objects of the invention are achieved in a preferred embodiment comprising a housing having axial openings extending into the housing from both ends. The lower end of the opening in the housing comprises a square or rectangular post entrance portion, two opposite sides of which extend into a terminal-receiving portion in a manner such that these two opposite sides provide a constricted section bearing on an extended length of post. The widths of the post-bearing areas are somewhat smaller than the width of the post so as not to interfere with mating of the terminal and the post. The widths of the post-bearing areas may be substantially nited States Patent 0 3,474,394 Patented Oct. 21, 1969 "ice equal to the distance between the contact areas of the forked terminals so as to provide a centering guide for a terminal inserted into a housing prior to the housing 'being placed on a post. The post entrance portion has a cross-section equal to or slightly smaller than the crosssection of the terminal post to provide a frictional sliding fit when the housing is telescoped onto the post. This frictional fit stabilizes the housing rotationally and in cooperation with the above-mentioned two opposite sides in at least one plane axially. The contact-receiving portion is provided with guide surfaces in the form of downwardly and centrally sloping guide planes leading into a lower centrally constricted section for each terminal. The constricted section for each terminal is provided by V- shaped ribs extending centrally downwardly from the upper opening. The dual function of these ribs will be presented later. Cavities on each side of the constriction extending downwardly from the upper end of the opening are provided to obtain uniform wall sections throughout the molding to reduce curing time and to increase dimensional accuracy. The upper contact-receiving portion is enlarged having a cross-section sufficient to admit the crimped insulation and wire portions of the elec trical conductor which are to be connected to the post. The housing is preferably used in conjunction with forktype spring contacts which are crimped onto the ends of the conductors. In the case of relatively large conductors, it is desirable that the thickness of the spring contact be substantially greater than half the thickness of the mating post in order to provide adequate wire retaining strength in the wire barrel of the contact and adequate contact force in the forked contact region. Thus, the provisions in the cavities of the housing provide operating clearance for such contacts.

The spring contacts comprise a forked section having a slot extending axially inwardly from their ends; the width of this slot near the ends between the contact areas being substantially equal to one-half the thickness of the terminal post and the width of the slot near the juncture of the tine being slightly larger than the post thickness so that two or more such contacts can be moved axially onto the post in straddling relationship thereto, each providing substantial contact force with its two contact surfaces against said post. The arrangement is such that the two fork-type terminals on the ends of the conductors can be moved into the housing and into the terminal-receiving portion thereof so that they will straddle the post with the opposed edges of the slot at the contact area bearing against the exposed sides of the post to establish the electrical connection.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are given for purposes of illustration and principles thereof and the manner of applying them in practical use so that they may modify them in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a fragmentary perspective view showing a portion of a panelboard having terminal posts extending therefrom and having an electrical connecting device in accordance with the invention mounted on one of the terminal posts;

FIGURE 2 is a cross-sectional view showing a connector housing in accordance with the invention in alignment with the terminal post and with a fork-type terminal which is to be connected to the terminal post;

FIGURE 3 is a view taken along lines 33 of FIG- URE 2;

FIGURE 4 is a view taken along lines 44 of FIG- URE 2;

FIGURE 5 is a view similar to FIGURE 2 but showing the connector housing mounted on the terminal post with the fork-type terminals sectioned at the upper ends of their slots and disposed in the housing and electrically connected to the post;

FIGURES 6 and 7 are views taken along lines 55 and 66 of FIGURE 4',

FIGURE 8 is a perspective view of a contact terminal on the end of a conductor of the type used for connecting the conductors to the terminal; and

FIGURE 9 shows an alternative embodiment of a connecting device in accordance with the invention.

FIGURE 1 shows a portion of a panelboard 4 having a multiplicity of terminal posts 2 mounted therein in accordance with a coordinate grid system. In the embodiment shown, the posts extend through board 4 to the opposite side thereof as shown at 2 so that individual modules containing circuit components may be mounted on the underside of board 4 and the necessary electrical connections between the modules can be made by means of projecting portions 2 of the posts by any suitable wiring method. In FIGURE 1, a relatively small conductor 8, which is matched to the size of post 2, provides electrical connection between the terminal posts as shown by means of clip-type connections 6 which are described more fully in the copending application of Robert F. Cobaugh, Ser. No. 171,074, filed Feb. 5, 1962, now US. Patent No. 3,239,918. Alternatively, connections may be provided between the posts in the region adjacent to the panel by conductors similar to *8 by means of welded or wrap-type connections.

The disclosed embodiment of the present invention is particularly intended for usage under circumstances where one or two

further conductors

10, 12 are to be disengageably connected to a post 2 and/ or where size limitations as regards the post or the conductors renders the employment of additional clip-type or wrap-type connections impractical. Thus, in FIGURE 1, it will be apparent that

conductors

10, 12 may be substantially larger than conductor 8 and could not conveniently be connected to a terminal post by means of a clip-type, wraptype, or weld connection. This does not preclude the advantageous use of

smaller conductors

10, 12 being disengageably connected to small posts as this is also contained within the invention. With small conductors only, the crimpable wire and insulation supporting barrels of the forked terminals are preferably proportional to the cross-section of Wire, the thickness of the forked end of the terminal is preferably identical to those used on larger conductors.

The disclosed embodiment of the invention comprises an insulating housing 14 into which fork-type contact terminals 16 (FIGURE 8) are adapted to be inserted. Each terminal 16 is crimped onto a conductor 10, by means of a pair of crimped

connections

26, 28, the terminal being secured to the strands of the Wire by crimp 26 and to the insulating sheath on the wire by means of crimp 28. The fork-type terminals comprise an elongated fiat tab 18 having a slot 20 extending axially inwardly from its end to define a pair of parallel tines 22. The inner portion of slot 20 is relatively narrow as shown at 46, the width of the slot being only slightly greater than the width of the post in this narrow portion. Inwardly directed contacts 24 are provided on the opposed edges of tines 22 adjacent the ends thereof and they are spaced relatively close together so that a high pressure electrical contact will be established between the contact terminals and the post when the terminals are moved into straddling relationship and spread by the posts in the manner described below. As can be discerned, tab 18 is oliset with respect to

connections

26, 28 by transition section 19.

Insulating housing 14 has legs or supports 29 extending from its underside so that it can be moved telescopically onto a single terminal post and will be supported above the surface of board 4 at a position such that it will not interfere with, or otherwise affect, clip-type connection 6 which is provided adjacent to the base of the post. Housing 14 has an

opening

30, 32, 34 extending centrally therethrough which is adapted to receive the upper portion of a terminal post 2 and a pair of contact terminals 16. Portion 30 of the opening which is adjacent to the lower end of the housing constitutes an entrance section and has a cross-sectional configuration closely conforming to and providing a sliding frictional fit with the cross-section of post 2 so that the housing will be stabilized against rotation on the post when the parts are in their assembled relationship. Contact-receiving portion 32 of the opening which is directly above entrance portion 30 has an hourglass configuration (see FIGURE 3) having a centrally constricted section 38 and a pair of laterally extending cavities 36. The Width of the constricted section (i.e., the distance between sides 39, 39) is substantially equal to the corresponding width of post 2 so that the opposed surfaces of this portion of the opening may bear against opposite sides of the post while the remaining sides will face outwardly and into cavities 36. The length of the constricted section in the plane at the forked connectors is materially less than the thickness of the post so that the contacts will bear on the post, as shown in FIGURES 3 and 6, and not on the cavity walls. The width of each cavity is substantially equal to and slightly greater than twice the thickness of forked portion 18 of an individual terminal so that two terminals in back-to-back relationship can be accommodated in the cavities as shown in FIGURES 5 and 6. The cross-sectional length of the cavities, normal to the width, is substantially equal to, and slightly greater than the overall width of tines 22 when they are spread apart by the post.

A pair of V-shaped ribs 48 are provided on opposite sides of conductor-receiving portion 4 and contact-receiving portion 32 of the opening in the housing. These ribs extend centrally downwardly in the opening and conform to chamfers 50 on the lower edges of tines 22 of terminals 16 and function to polarize and locate the terminals in a proper and sequential manner during insertion in a manner described below.

Upper portion 34 of the opening has a cross-section sufiiciently large to admit a pair of terminals disposed with their fork portions in back-to-back relationship and with their

crimped portions

26, 28 disposed in parallel relationship with each other. In this respect, it will be noted that upper section 42 of the cavity of the upper end of the housing is slightly enlarged in order to admit insulation crimps 28 of the terminals. The transition portion between contact-receiving portion 32 of the opening and conductor-receiving portion 34 comprises inclined surfaces 40 which slope from opposite sides of the housing downwardly towards cavities 36 for the purpose of guiding the ends of tines 22 of the contacts into the cavities and into straddling relationship with the exposed sides of the post as explained below.

The inner ends of surfaces 40, which form the sides of cavities 36, are slightly smaller in length than the sides of these cavities and constricted sections 38, as illustrated in FIGURE 4, and this occurs at the transition between the tab and wire barrel to frictionally retain the terminals in the housing without restricting action of the tines.

In normal point-to-point connection use, housing 14 is first mounted on a post 2 to which it is desired to connect

external conductors

10, 12. A terminal 16 is then positioned above a desired cavity 42, as shown in FIG- URE 2, in alignment with the post and with its tine portions in general alignment with cavities 36. The terminal is then pushed downwardly against guide surfaces 40 which guide its forked ends toward the post and cavities 36, in engagement with sections 38 and into straddling relationship to the post. If required, a second terminal in like manner, may then be positioned in or removed from cavity 42. In the finished connection, the terminals will be in back-to-back relationship with their

crimp portions

26, 28 facing in opposite directions. It is not essential that the precise sequence described above be followed; for example, the terminals can be inserted into the housing together, back-to-back, when complete wiring harnesses are made up and it is convenient to do so. Many times, however, only a single connector will be required in a housing.

In the case of the particular embodiment of the invention, the terminals can be inserted into the housing only in the intended manner. That is to say, inclined surfaces 40 will function to guide the ends of tines 20 towards the post if the terminal is reasonably aligned with cavities 36, as above. Ribs 48 in cooperation with chamfered edges 50 insure that the conductor-retaining

crimps

26 and 28 will be properly positioned in their respective cavities so that either terminal can be connected or disconnected independent of the other. In other words, with reasonable initial alignment, it is difficult to insert the terminals in any orientation other than that shown in FIGURES 5 and 6. Sections 38 serve a dual function, as self-centering means to enable the forked ends to be properly centered with respect to post 2 and as bearing areas for bearing against post 2.

Although terminal post 2 has a small cross-section relative to the size of housing 14 and the size of forktype terminals 16, the housing is stabilized against unintentional movement in all directions by the manner in which the housing, cooperating with a terminal or terminals, is fitted onto the post. As previously noted, the housing is stabilized against rotation on the post by constricted entrance portion 30 of the opening since this entrance portion conforms to the cross-section of the post and has a close fit therewith. The housing is stabilized against rocking motion in the plane XX of FIGURE 6 by surfaces 39 of the terminal-receiving portions of the opening in the housing. These surfaces 39 extend along and bear against the post for a substantial portion of its length, as best shown in FIGURE 5, so that rocking of the housing to the left or right in FIGURE 5 is elfectively prevented. Finally, rocking of the housing in the plane YY of FIGURE 6 is prevented by the relationship of fork-type terminals 16 to post 2 and their relationship to housing 14. The stability of the housing in the YY plane of FIGURE 6 depends upon the close fit of the terminals in cavities 36 and the fact that the upper end of the post extends into narrow sections 46 of the slots in the terminals. By virtue of the close fit of the terminals in cavities 36, the terminals are permitted only very limited movement within the cavity as is best shown in FIGURE 6. By virtue of the fact that the post extends into narrow portions 46 of slots 20 of the terminals, very little relative movement of the terminals with respect to the post is permitted.

The stability if the housing in the YY plane can also be explained by assuming that a force will be applied to the housing from the right or left in FIGURE 7. Such a force would ordinarily tend to rock the housing in the plane of the drawing of FIGURE 7. However, such a force when applied to the housing would actually cause only very limited rocking motion for the reason that this force would be transmitted to terminals 16 (by virtue of the close fit of these terminals in cavities 36) and thence to post 2 by virtue of the relatively close fit of the post in upper narrow portion 46 of slot 20. It should be noted that tines 20 of the terminals are highly resistant to flexure in their own planes in the load-bearing areas (within slot portion 46) because of the fact that the force is transmitted at the relative rigid upper ends of the tines near the upper end of slot 20. This fact is of importance in maintaining the electrical contact between contacts 24 of the terminal and the sides of the post when a force is applied to the housing from one side thereof, as viewed in FIGURE 7.

FIGURE 8 shows an alternative embodiment of the invention comprising a housing 14' having a pair of openings extending therethrough which is adapted to be mounted on a pair of adjacent terminal posts of the panelboard. The openings in the housing of FIGURE 8 may be in all respects similar to the opening in housing 14 and the relationship of the housing to the posts and the relationship of the terminals to the housing and post would be as described above. One advantage of the type of housing shown in FIGURE 8 is that in the event of the application of a torque to the housing, the two posts extending into the housing would provide added stability and prevent twisting of the housing with respect to the board. Obviously, a housing in accordance with the invention could be made with many desired numbers of post-receiving openings therein.

It will, therefore, be appreciated that the aforementioned and other desirable objects have been achieved; however, it should be emphasized that the particular embodiments of the invention, which are shown and described herein, are intended as merely illustrative and not as restrictive of the invention.

What is claimed is:

1. An electrical connector for connecting an electrical conductor to a terminal post comprising an electrical terminal and a dielectric housing, said terminal having a section electrically connected to said conductor and a forkedcontact section, said dielectric housing having a passageway extending therethrough, said passageway at one end having a configuration conforming substantially to the configuration of said post and into which said post is to be disposed, said passageway having a terminal-receiving area into which said post and said terminal extend, said terminal-receiving area having parallel planes spaced apart a distance sufficient to permit receipt of said terminal therebetween and bearing surface means which constrain said post to remain at least partially between said planes substantially centered relative to said forked-contact section to define centering means to center ends of said forked-contact section with respect to said post, surface portions in said housing retaining said terminal after insertion in said terminal-receiving area.

2. A disengageable electrical connector for connecting conductive means to a terminal post extending outwardly from a mounting member, said electrical connector comprising an electrical terminal and a dielectric housing, said terminal having a section electrically connected to said conductive means and a forked-contact section, said dielectric housing having an opening extending therethrough, said opening provided with a post entrance, a terminal-receiving section and a terminal entrance, said post entrance conforming to the cross-sectional configuration of said post for snug engagement therewith, said terminal-receiving section having cavity means extending outwardly from opposite sides of said post entrance, said cavity means including surfaces spaced apart a sufiicient distance to permit receipt of said forked-contact section therebetween, and bearing surface means extending along opposite surfaces of said terminal-receiving section for hearing against opposite sides of the part of said post that extends into said terminal-receiving section and for cen tering contact ends of said forked-contact section with respect to said post so that said contact ends engage other opposite sides of said post.

3. A connector according to 2 wherein said housing includes a pair of parallel passageways with at least one terminal in each for cooperation with a pair of adjacent contact elements on a panelboard.

4. A connector according to 2 wherein said housing includes a pair of substantially identical parallel passageways with at least one terminal in each for cooperation with a pair of adjacent contact elements on a panelboard.

5. An electrical connector for connecting conductor means to a terminal post extending outwardly from a mounting member, said electrical connector comprising an electrical terminal and a dielectric housing, said electrical terminal having a section electrically connected to said conductor means and a forked-contact section, said housing having an opening extending therethrough, said opening having an entrance into which said post extends, said entrance conforming substantially to the configuration of said post for snug engagement therewith, said opening having a terminal-receiving section defining cavities extending parallel to an insertion axis of said opening, bearing-surface means along op posed sides of said terminal-receiving section for bearing engagement with opposite sides of the part of said post that extends into said terminal-receiving section, each of said cavities having rib means centrally located along a surface spaced outermost from said axis, said rib means and said opposed sides defining dual terminal-receiving areas in which the forked-contact sections of two electrical terminals are disposed in electrical engagement with other opposite sides of said post, said bearing-surface means providing centering means for centering contact ends of the forked-contact sections with respect to the post.

6. An electrical connector for connecting electrical conductors to the contact elements of a coordinate grid systerm which includes terminal posts mounted in rows on a panelboard, said connector comprising a dielectric housing having a pair of passageways extending therethrough, and a pair of electrical terminals respectively disposed in said passageways to engage a pair of adjacent contact elements of the grid system with the housing arranged to fit over the contact elements in spaced relation to the adjacent elements of the grid, one of said terminals having a section for electrical connection to a conductor and a forked-contact section, the passageway receiving said termnal at one end having a construction snugly to receive a terminal post, said passageway having a terminalreceiving area into which said post and terminal extend and an enlarged terminal entrance area at the other end to receive the conductor connecting section, said terminal receiving area having parallel planes spaced apart a distance sufficient to permit receipt of said terminal therebetween and constraining surface means which constrain said post to remain at least partially between said planes substantially centered relative to said forked-contact section to define centering means to center ends of said forked-contact section with respect to said post, and surface portions in said housing retaining said terminal in said terminal-receiving area.

References Cited UNITED STATES PATENTS 3,325,770 6/1967 'Hammell et al. 339-l76 MARVIN A. CHAMPION, Primary Examiner