US3255428A

US3255428A - Electrical connectors

Info

Publication number: US3255428A
Application number: US411212A
Authority: US
Inventors: Clyde F Robbins
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1964-11-16
Filing date: 1964-11-16
Publication date: 1966-06-07
Anticipated expiration: 1983-06-07
Also published as: GB1076687A

Description

June 7, 1966 c. F. ROBB INS 3,255,428

ELECTRICAL CONNECTORS Filed Nov. 16, 1964 2 Sheets-Sheet l z/ll'l'I/lY/[L III I June 7, 1966 c. F. ROBBINS 3,255,428

ELECTRICAL CONNECTORS Filed Nov. 16, 1964 2 Sheets-Sheet 2 3,255,428 ELECTRICAL CONNECTORS Clyde F. Robbins, Milwaukee, Wis., assignor toCutler- Hammer, Inc., Milwaukee, Wis., a corporation of Dela- Ware Filed Nov. 16, 1964, Ser. No. 411,212 8 Claims. (Cl. 339-95) This invention relates to electrical connectors and more particularly to quick-connect connectors of the plug-in terminal type.

While not limited thereto, the invention is especially applicable to connection of conductors or wires to miniature electrical devices such as switches, relays and the like where the space for the connector is limited and a strong connection is required.

An object of the invention is to provide improved electrical connectors.

' A more specific object of the invention is to provide double-grip connectors of the plug-in terminal type.

Another specific object of the invention is to provide improved quickly-connectable electrical connectors of small size having superior mechanical characteristics.

Another specific object of the invention is to provide improved quickly-detachable electrical connectors of small size having superior electrical and mechanical characteristics.

A further specific object of the invention is to provide improved electrical connectors of small physical size particularly in vertical dimension which are economical to produce and easy to assemble.

Other objects and advantages of the invention will hereinafter appear.

These and other objects and advantages of the invention and the manner of obtaining them will best beunderstood by reference to the following description of embodiments thereof taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a cross-sectional view of an electrical connector constructed in accordance with the invention;

FIG. 2 is an isometric view of the connector spring clip of FIG. 1;

FIG. 3 is a cross-sectional view like FIG. 1 but showing a relatively large diameter conductor inserted in the connector;

FIG. 4 is a cross-sectional view taken along line 44 of FIG. 3;

FIG. 5 is a cross-sectional view like FIG. 3 showing the double-grip action when the conductor is pulled;

FIG. 6 is an isometric view of a portion of the pocket in which the connector is retained;

FIG. 7 is a cross-sectional view like FIG. 1 but showing a relatively small diameter conductor inserted in the connector;

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7;

FIG. 9 is a cross-sectional view like FIG. 7 showing the double-grip action when the conductor is pulled;

FIG. 10 is an isometric view of a modified connector spring clip;

FIG. 11 is a cross-sectional view of a connector having the modified spring clip of FIG. 10 and showing an intermediate size conductor inserted therein; and

FIG. 12 is a cross-sectional view taken along line 12 12 of FIG. 11.

Referring to FIGS. 1-6, there is shown in accordance with the invention an electrical connector of the plug-in terminal type mounted in the insulating housing 2- of an electrical switch or the like. Housing 2 is shown as being comprised of a base 2a and a cover 2b. Base is provided with a small pocket or cavity 4 opening at the top and having a generally rectangular shape in 3,255,428 Patented June 7, 1966 flat bottoms whereas the intermediateportion may incline at an angle of about 45 degrees or more from the horizontal.

As shown in FIG. 6, the raised or shallower portion 4c of the cavity is constricted so that its width is only.

one-half or less than one-half the width of the deeper portion 4a of the cavity and is alined with one side of the deeper portion. The corner between the wider portion and the narrower portion of the cavity is provided with a bevel 4d. This angular wall provided by the bevel 4d is engaged by the end of a wire pushed into the cavity to cam the wire to one side of the cavity.

A hole 6 extends from the upper part of the deeper end of cavity 4 through the wall of the base. As shown in FIG. 4, hole 6 is tapered in cross-section to allow insertion of a wire through the wider part and to allow insertion of a release tool through the narrower part of the hole.

An electrical terminal 8 extends along the upper surface of base 2a to overlie cavity 4. As shown in FIGS. 4 and 6, terminal 8 may be fiat and the opposite upper corners of the walls of cavity 4 may be recessed at 4e to accommodate a terminal 8 slightly wider than the cavity to fix the terminal over the cavity. This terminal covers the cavity and an insulating cover plate 2b lies over terminal 8 and hole 6. While the housing has been shown as comprised of a base and a cover, it will be apparent that other forms are possible; for example, the part of cover 2b overlying hole 6 could be molded integrally with the base and the remainder of the cover omitted. In such version, terminal 8 alone would cover the cavity and hole 6 would open only at its opposite ends and not at the top.

A connector spring clip 10 of the double-grip type rests in the deeper portion 4a of the cavity. Clip 10* is provided with a substantially U-shaped configuration and comprises a short strip of thin spring metal bent back roundedly upon itself at the center. As shown in FIG. 1, leg 10a of clip 10 may be slightly shorter than the other leg 10b. Clip 10 is dropped in the deeper portion of cavity 4 yoke portion first so that terminal 8, when placed in position, engages and slightly flexes leg 10a of the clip to hold it at a slant as shown in FIG. 1 and to keep it from rattling in the pocket.

As shown in FIGS. 1 and 6, raised portion 40 of the cavity which is narrower than the remainder of the cavity and otfset to one side thereof provides shoulder 4 one on side wall continuing in the direction of incline 4b for some distance and then terminating in a vertical wall 4g. Leg 10b of the clip rests on this shoulder and is retained thereby so that the other leg can be flexed sufiiciently to hold the connector clip immobile within the cavity and to keep it from rattling therein.

Connector clip 10 is arranged to grip the end portion of an electrical wire 12 from which the insulation has been removed. As shown in FIG. 3, hole 6 is large enough to receive a portion of the insulated part of the wire whereas the bare part of the wire flexes leg 10a as it is forced between terminal 8 and the clip and pushed all the way into the narrow end of the cavity. The bare wire passes freely over and past leg 10b of clip 10. When so inserted, the bare wire slides along terminal 8 and is held in good electrical contact therewith by the clip.

As shown in FIG. 4, wire 12 is inserted into the cavity through the larger side of hole 6. The smaller side of hole 6 remains open so that a tool such as a pin may be inserted to pry leg a away from the wire to release the latter for removal.

As shown in FIG. 5, connector spring clip 10 affords double-grip function if the wire is pulled. When the wire 12 is pulled in the direction of the arrow, it will be restrained by leg 10a of the clip biting into the wire and clamping the wire against terminal 8. A strong pull will cause the clip to flex elastically, slide and rotate in the dee er portion of the cavity so as to force up the other leg 10!) into biting engagement with the wire for positive gripping. Both legs of the clip now restrain the wire to prevent it from being pulled completely out. When the wire is released, the clip restores and moves the wire back to the position shown in FIG. 3.

FIGS, 7, 8 and 9 show how the same connector spring clip can be used for connecting a relatively thin wire 14- to terminal 8. The wire may be either a solid wire or a stranded wire which has been tinned or dipped in solder to stiffen it. Since the upper leg 10a of clip 10 is long enough to be slightly flexed by terminal 8 before a wire is inserted, the clip is capable of engaging and retaining even a thin wire as shown in FIGS. 7 and 8. When this wire is pulled, the clip elastically flexes and rolls or slides in the cavity to bring up the other leg also into biting engagement with wire 14.

While leg 10a of the connector spring clip has been shown in FIGS. 19 as being slightly shorter than the other leg 10b, it will be apparent that the relative lengths of the two legs may depend on the range of wire sizes that it is desired to connect. For example, if only small wire is to be connected, leg 10b could be longer than that shown in FIG. 7. A requirement is that leg 10]) should have a length allowing the wire to pass thereover to the rear end of the narrower portion of the pocket when it is inserted. Leg 10b must be long enough so that it will cOrne up and grip the wire when the wire is pulled. Leg 16a is preferably long enough so that it will be engaged or slightly flexed by the terminal to keep the clip from rolling in the pocket before the wire is inserted thereinto.

FIGS. 1012 show a modified connector spring clip 16 for holding a conductor 18 against a modified terminal 20. As shown in the isometric view in FIG. 10, clip 16 differs from that hereinbefore described in that the ends of the two legs thereof are cut at a small angle. Both legs are preferably provided with the same angle in the same direction. These angular ends of the clip tend to force the wire to one side of the cavity. As shown in FIGS. 11 and 12, terminal 20 is Wider and has a downwardly bent edge 20a fitting into a deeper notch in one upper corner of the wall of the cavity on the side corresponding to the larger side of hole 6. The angular end on leg 16a of the clip tends to move wire 18 into the 90 degree corner between terminal 20 and its bent edge 20a to afford a large area electrical contact between the wire and the terminal.

While the ends of the U-shaped connector spring clip have been illustrated as being cut straight across in FIGS. 1-9 and as being cut at an angle in FIGS. 1012, it will be apparent that other forms are possible. For example, the ends of the spring clip could be provided with V- notches at various angles or could be pointed, that is, an inverted V, at various angles. These slanted or pointed ends tend to keep idle clips from rattling. A preferred form may be a flat terminal plate as shown in FIGS. l-S in combination with a U-shaped connector spring having slightly angled ends on its legs as shown in FIGS. 1012. Also, when two connectors for a pair of wires are used in a switch base, the angles on the legs of the two springs are arranged in opposite directions to force the two wires as far apart as possible in a two-pole switch. This requires left-hand and right-hand springs. An alternative would be pointed ends on the legs of the connector spring in combination with the narrow portion in the cavity as a molded guide for the wire. A like pointed leg spring could be used for both poles of a two pole switch to 'force the wires far apart.

While the invention hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that I do not intend to confine my invention to the particular preferred embodiments of electrical connectors disclosed, inasmuch as they are susceptible of various modifications without departing from the scope of the appended claims.

I claim:

1. A releasable double-grip electrical connector comprising:

an insulating housing having a pocket therein open at the top;

said pocket comprising an inclined wall and being free of any impediments to enable dropping of a connector clip thereinto through its open top;

a connector clip comprising a U-shaped strap of spring material freely resting in said pocket with a first leg thereof extending at an upward angle in the pocket and with the second leg thereof lying on said inclined wall;

an electrical terminal member overlying said pocket;

a hole in the wall of the housing opposite said inclined wall for receiving the bare wire end portion of an insulated conductor;

said first leg of said connector clip having a length relative to the height of the pocket such that insertion of said wire through said hole causes flexing thereof and pressing of said bare wire against said terminal member as said bare wire passes freely over the end of said second leg of said clip;

and the lower bent portion of said clip being rounded sufficiently to hug the walls of said pocket and said second leg of said clip having a length relative to the height of said pocket such that pulling on said conductor causes said first leg to elastically flex while it remains in biting engagement with said bare wire and causes the bent portion of said clip to flex elastically and slide and rotate in said pocket to force the end of said second leg into biting engagement with said bare wire whereby both legs of said clip grip said bare wire in a direction restraining removal thereof from contact with said terminal.

2. The invention defined in claim 1, wherein:

the legs of said connector clip are provided with straight-across cut ends so that they are at a right angle wit-h the edges thereof.

3. The invention defined in claim 1, wherein:

the legs of said connector clip are provided with angular ends slanting at a small angle from one edge of said connector clip to the other edge thereof.

4. The invention defined in claim 1, wherein:

said pocket is extended through substantially a half of the upper portion of said inclined wall to provide room for insertion of the bare Wire beyond said second leg of said connector clip, the remainder of the upper portion of said inclined wall providing a rest for the end of said second. leg of said connector clip.

5. The invention defined in claim 1, wherein:

said electrical terminal member comprises a flat plate having a down-turned edge portion forming a right angle at one upper corner of said pocket providing larger contact area for the bare wire.

6. The invention defined in claim 1, wherein:

said hole in the housing wall opposite said inclined wall is provided with an elongated cross-sectional shape to provide space alongside the bare, wire for insertion of a release tool.

7. The invention defined in claim 1, wherein:

said first leg of said connector clip is provided with a length sufficient to cause it to be slightly flexed by said terminal member before the bare wire is 5 inserted thereby maintaining said second leg in contact with said inclined wall and said bent portion thereof in contact with said opposite wall of said pocket. 8. The invention defined in claim 1, together with: an insulating cover overlying said terminal member to close said pocket; and the arrangement being such that the connector can be assembled -by'dropping the connector clip in the pocket, placing the terminal member over the pocket and securing the insulating cover to close the top of the pocket.

References Cited by the Examiner UNITED STATES PATENTS 6 2,738,482 3/1956 Benander 33995 X 2,993,190 7/1961 Sams et al. 33995 X 3,138,421 6/1964 Locher et a1 339-95 References Cited by the Applicant UNITED STATES PATENTS 1,950,826 3/1934 Smart. 2,705,785 4/1955 Benander. 2,780,791 2/ 1957 Morschel. 2,883,641 4/ 1959 Despard. 2,913,698 11/1959 Bromley.

FOREIGN PATENTS 838,778 7/1952 Germany.

JOSEPH D. SEERS, Primary Examiner.

W. D. MILLER, Assistant Examiner.

Claims

1. A RELEASABLE DOUBLE-GRIP ELECTRICAL CONNECTOR COMPRISING: AN INSULATING HOUSING HAVING A POCKET THEREIN OPEN AT THE TOP; SAID POCKET COMPRISING AN INCLINED WALL AND BEING FREE OF ANY IMPEDIMENTS TO ENABLE DROPPING OF A CONNECTOR CLIP THEREINTO THROUGH ITS OPEN TOP; A CONNECTOR CLIP COMPRISING A U-SHAPED STRAP OF SPRING MATERIAL FREELY RESTING IN SAID POCKET WITH A FIRST LEG THEREOF EXTENDING AT AN UPWARD ANGLE IN THE POCKET AND WITH THE SECOND LEG THEREOF LYING ON SAID INCLINED WALL; AN ELECTRICAL TERMINAL MEMBER OVERLYING SAID POCKET; A HOLE IN THE WALL OF THE HOUSING OPPOSITE SAID INCLINED WALL FOR RECEIVING THE BARE WIRE END PORTION OF AN INSULATED CONDUCTOR; SAID FIRST LEG OF SAID CONNECTOR CLIP HAVING A LENGTH RELATIVE TO THE LENGTH OF THE POCKET SUCH THAT INSERTION OF SAID WIRE THROUGH SAID HOLE CAUSES FLEXING THEREOF AND PRESSING OF SAID BARE WIRE AGAINST SAID TERMINAL MEMBER AS SAID BARE WIRE PASSES FREELY OVER THE END OF SAID SECOND LEG OF SAID CLIP; AND THE LOWER BENT PORTION OF SAID CLIP BEING ROUNDED SUFFICIENTLY TO HUG THE WALLS OF SAID POCKET AND SAID SECOND LEG OF SAID CLIP HAVING A LENGTH RELATIVE TO THE HEIGHT OF SAID POCKET SUCH THAT PULLING ON SAID CONDUCTOR CAUSES SAID FIRST LEG TO ELASTICALLY FLEX WHILE IT REMAINS IN BITING ENGAGEMENT WITH SAID BARE WIRE AND CAUSES THE BENT PORTION OF SAID CLIP TO FLEX ELASTICALLY AND SLIDE AND ROTATE IN SAID POCKET TO FORCE THE END OF SAID SECOND LEG INTO BITING ENGAGEMENT WITH SAID BARE WIRE WHEREBY BOTH LEGS OF SAID CLIP GRIP SAID BARE WIRE IN A DIRECTION RESTRAINING REMOVAL THEREOF FROM CONTACT WITH SAID TERMINAL.