US2553083A

US2553083A - Sleeve type elbow terminal

Info

Publication number: US2553083A
Application number: US24552A
Authority: US
Inventors: Howard A Elliott
Original assignee: Essex Wire Corp
Current assignee: Essex Wire Corp
Priority date: 1948-05-01
Filing date: 1948-05-01
Publication date: 1951-05-15
Anticipated expiration: 1968-05-15

Description

y 1951 H. A. ELLIOTT 2,553,083

SLEEVE TYPE ELBOW TERMINAL Filed May 1, 1948 INVENTOR. HOWARD A. ELLIOTT 14 TTORNEV Patented May 15, 1951 SLEEVE TYPE ELBOW TERMINAL Howard A. Elliott, Detroit, Mich., assignor to Essex Wire Corporation, Detroit, Mich., a corporation of Michigan Application May 1, 1948, Serial No. 24,552

4 Claims. (01. 173269) The present invention relates to an improved sleeve type elbow terminal particularly but not exclusively adapted for use as an electrical terminal used with automobile ignition systems and the like.

Prior to the present invention, such sleeve type elbow terminals have been commonly fabricated from sheet metal stock to provide an essentially tubular L-type sleeve or socket open at both ends. One sleeve end of the terminal is adapted for permanently receiving in electrical contact the end of an insulated wire conductor. The other sleeve end serves as a female type sleeve terminal for detachably engaging the mating plug or male type terminal of another conductor. The bend at the elbow of such sleeve terminals has been a sourceof weakness in the conventional construction. In forming the elbow the metal is unequally stressed and is weakened so that the elbow bends too readily, resulting in breakage of the terminal at the elbow.

An object of the present invention is to provide an improved angular sleeve type terminal which is particularly resistant to bending or breakage at the elbow.

Another object is to provide an improved sleeve type elbow terminal which is particularly adapted for use with automotive ignition systems and which provides an angle at the elbow of less than 90, so as to present the terminal in use at a particularly convenient angle to the operator.

Other objects are to provide an improved angular sleeve type terminal of the character described which is readily adapted for economical manufacture by mass production methods from strips of sheet metal stock; and to provide improved mean in such a terminal for positively electrically contacting its permanently attached conductor and for securely gripping the insulation of the latter without the use of solder or other bonding material.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding part in the several views.

In the drawings:

Fig. 1 is a fragmentary elevation showing a terminal embodying the present invention and an end Portion of a conductor cable detached therefrom.

Figs. 2 and 3 are end elevations of the terminal shown in Fig. 1, taken from the left and right ends respectively. I

Fig. 4 is a front elevation of the terminal shown in Fig. 1.

Fig. 5 is a schematic plan view showing a strip of sheet metal from which the terminal of the present invention is fabricated, and indicating not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

A preferred embodiment of the present invention comprises a sleeve type elbow terminal which is formed by passing a strip of an electrically conductive sheet material, such for example as a copper alloy, through a series of progressive die cutting and forming operations.

In one of the early operations, a bowl-shaped indenture comprising a spherical or spheroidal segment is embossed into the strip in such a mannor as to provide a uniformly stressed area. This indenture later becomes the region of the bend of the elbow and provides great strength and resistance to bending of the formed terminal from its final angular shape. In the succeeding operations, the strip is punched and indentured to provide gripping means and a plurality of jagged inturned tangs, the sides are rolled to the sleeve form, and the elbow shape is formed by bending the material at the spheroidal indenture.

One sleeve leg of the resulting terminal is adapted for securely and permanently gripping the end of an insulated wire conductor inserted therein, and is preferably clamped around the conductor in the manufacture of the terminal, although it may be clamped around the conductor on the job if desired. The jagged inturned tangs are provided by the said conductor receiving sleeve leg for embedding into and positively gripping the insulation of the conductor. Each tang is adapted in size so that the area of the insulation cut thereby will be insuflicient to permit stripping of the insulation from the conductor.

The conductor receiving sleeve of the terminal also provides an inward projecting conductor contacting nib adapted to make positive electrical contact with an exposed portion of the conductor inserted into the sleeve. Prior to insertion of the conductor into the sleeve terminal, it is preferred that an end portion of the conductor is exposed and bent rearwardly in a U-bend against the external side of its insulation. Thereafter the conductor is inserted into the sleeve therefor with its exposed end portion aligned to contact the aforesaid inward projecting conductor contacting nib. Upon closing the sleeve tightly around the insulation, the said conductor contacting nib en.-

gages the exposed end portion of the conductor in positive electrical contact.

A particular embodiment of the present invention is shown in Figs. 1 through 4. The terminal:

comprises two sleeve legs I and I2 bent at a right angle around the essentially spheroidal emboss-- ment or indenture I4 at thecap or fold of the elbow. The sleeve leg I0 is adapted to receive and electrically contact the end of an insulated,

cable I6 having the insulation I3. In order to assure positive electrical contact with an exposed rearwardly bent end portion 20 of the cable I6, the sleeve leg I provides the inward projecting conductor contacting nib 22. Permanent andsecure gripping of the insulation I8 is achieved by the plurality of jagged inturned tangs 24.

The insulated conductor I6 is preferably permanently and securely enclosed within the sleeve leg I0 during the formation of the latter, with the nib 22 contacting the exposed cable end portion 28: and with the inturned tangs 24- cutting into the insulation I8. However, the conductor I6 may be inserted on the job if desired by opening the sleeve leg I8 along its longitudinal slit 26 (Fig. 4) which spaces the adjacent sleeve edges 28 and 30 along the line of symmetry at the interior angle of the elbow. Thereafter the sleeve leg I0 is closed tightly around the inserted conductor cable I5-I8 as described above.

The sleeve leg I2 of the completed terminal provides a plurality of axially extending ovallike recesses 32. Two of the opposed bars 34 between the recesses 32 are crimped slightly inward, so as to provide resilient retaining and electrical contacting mean for detachably gripping a conventional male or plug-type terminal insert.

The terminal of the present invention may be economically fabricated from a thin fiat strip 35 of a: copper alloy such as bronze or other suitable electrical conducting material having the desiredstrength and forming characteristics. Fig. 5 schematically indicates one method utilizing a progression of cutting: and forming operations through which any particular portion of'thestrip 35 or blank formed therein is subjected in the formation of a terminal embodying the present invention. It is to be understood, however, that said terminal may be made by other methods known to those skilled in the art. As here shown, the respective steps of a preferred process are lettered A through G for future reference, the first step being shown at A and the subsequent operations being indicated step by step to the right in Fig. 5.

The general principles of the die cutting and forming operations required. for the fabrication of a terminal of the character described from a strip of sheet metal. stock are well knownto the tool and die making art and areaccordinglynot described herein. Briefly, the strip 35 is intermittently indexed. from left' to rightthrough a series of progressive cutting and forming dies. Each progressive die performs its workopera.- tion on the portion of the strip indexed; thereat; so;,that :the resulting strip will appear somewhat as indicated-in Fig. 5. A. preferred sequencev of. operation. in, the formation of the terminal? rolled inward in the later operations.

shown is described in more detail in my co-pending application, Serial No. 24,551, filed May 1, 1948, to which reference is hereby made for the disclosure of any additional details which may be required.

As a first step, the end of the strip 35 is embossed with the said spheroidal indenture I4 which later becomes the. fold or cap of the elbow. Itwill be apparent'to those skilled in the art that the indenture I4 may be formed at any one of various stages in the progressive formation of the terminal, provided that the portion of the strip 35 whereat the indenture I4 is formed is still essentially fiat. Theindenture or embossment I4 wilt be: of less value as a reinforcement if formed after the sidewalls of the terminal are Furthermore, the early formation of the indenture I4 permits its use for centering the strip 35 as it is progressively indexed to the subsequent cutting andforming operations.

I-he embossing of the indenture I i stresses and work hardens the material of the strip 35 at the region which eventually becomesthe fold of the elbow and also provides an essentially spheroidal surface for the elbow capwhich uniformly distributes forces tending to distort the elbow from its final angular shape. Thus isprovided an exceptionally strong angle type terminal which is particularly resistant: to bending at the elbow. The strengthening aiiordedby'the spheroidal indenture IA may also be achieved by raising the latter in the strip 35, Fig. 5, so that theresultant elbow capwill be concave rather than convex. However, the preferred: construction shown permits afolding and blending of. the terminal about the convex indenture lid and provides a terminalof improved appearance. Likewise, the present invention is obviously notlimited to the spherical embossment. M. at the elbow,. since embossed indentures having other surfaces, as for example asymmetric multi-facet indenture, will provide a Work-hardened, stressrdistributing elbow reinforcement within the. spirit of thepresent invention.

In the step-B,.the strip 35 is blanked out-around the indenture, I4, leaving the resulting blank connected: to=the bodyof'the strip by the connecting neck 35.v Simultaneously the truncated triangular: notches 38 are cut. in the.- blank to remove the excess; material at the. lateral sides of the indenture: I4 and to. permit formation of. the elbow bend. Each. notch 38 is identified by the small axially extending base 40. terminating in the axially spaced points 42 and 4t referred: to; hereinafter.

In. subsequent operations; indicated at C, the plurality of OVEilr'likfi'. recesses 32. are formed. 'As" indicated: at D,.the. bars 3A1 between thetwolateral pairs: of recesses. 32. are crimped upwardly, but the aforementioned nib; 2-2 and jagged tangs 24' are raised from the. underside of the portion of the. blank which eventually'become the sleeve leg I 0- Intheoperations indicated at E, the afore-- mentioned laterali edges 28.: and. 311- of. the leg II] are bent slightly upward. and? the corresponding: lateral edges 45 and 48 of the leg' H? are similarly bent; upward. At'a later stageathe edges 28', 3.0,

'46, anda IB; are: rolled. further, upwardand towardeach; other-to form the ,semirclosed sleeves ber indicated at F. In the final operations,.the.

legs Illand: 'l2i areibent. at right anglesto. each othen' as; indicafted: at: G; and. the. sleeves: thereof fare closed to the final position indicated iinliigszl-l f through 4. If desired, prior to the final closing of the sleeve leg H), the cablelfi-IB is inserted and permanently secured therein by folding the sleeve leg [9 tightly around the insulation i8 as heretofore described.

In the elbow bending operation, the axially spaced points 42 and 44 at opposite ends of each base 40 are compressed and swagged essentially to a single thickened. reinforcement 50, Fig. 1, at the base of the slit 52 which remains after the elbow forming operation as a remnant of the recess 38. Not only is the base of the slit 52 reinforced by the thickening of the excess material thereof resulting from the compression of the base 40 to essentially a single point, but the swagging and flattening operations work harden the thickened material 59 resulting in the formation of an exceptionally strong reinforcement for the bend. of the elbow.

Although the present invention is illustrated by means of a right angle elbow, it is apparent that an elbow may be provided. at other than a right angle. An essentially 45 angle is particularly desirable in some instances, as for example with certain types of automobile ignition systems, and permits the terminal to be conveniently faced toward the operator in use.

From the foregoing, it is apparent that I have disclosed a superior sleeve type elbow terminal which is readily adapted for efficient and economical manufacture by conventional progressive automatic die cutting and forming processes. The completed terminal provides means for securely and permanently gripping a cable in electrical contact therewith and is characterized by both an improved appearance and in greatly increased strength and resistance to bending at the elbow in comparison to similar terminals of conventional construction.

Having thus described my invention, I claim:

1. A sleeve type elbow terminal formed of a strip of sheet material and including a pair of joined legs, one leg being secured to a conductor, a work-hardened embossed spherical segment comprising the cap of the elbow which connects the adjacent ends of said legs to reinforce the apex of the elbow and form a smooth rounded 6 contour thereat, said spherical segment comprising at least half the width of the strip at the point where it is formed, the elbow terminal including a slit in the bottom thereof which essenially bisects the angle of the elbow and extends toward and terminates short of said elbow cap.

2. An elbow terminal according to claim 1 and further characterized in that the center of curvature of the spherical segment lies upon the intersection of the longitudinal axes of said legs.

3. An elbow terminal according to claim 1 and further characterized in that the center of curvature of the spherical segment lies upon a line which bisects the angle of the elbow.

4. A sleeve type elbow terminal formed of a strip of sheet material and including a pair of joined legs, one leg being secured to a conductor, a work-hardened embossed spherical segment comprising the cap of the elbow which connects the adjacent ends of said legs to reinforce the apex of the elbow and form a smooth rounded contour thereat, said spherical segment comprising at least half the width of the strip at the point where it is formed, the elbow terminal including a slit in the bottom thereof which essentially bisects the angle of the elbow and extends toward and terminates short of said elbow cap, and a flat thickened reinforcing portion at the base of said slit on each side of the terminal which joins the side walls of the legs of the terminal.

HOWARD A. ELLIOTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 376,666 Lee Jan. 17, 1888 994,930 Johnston June 13, 1911 1,553,060 Anderson Sept. 8, 1925 1,566,768 Otis Dec. 22, 1925 1,808,335 Aufiero June 2, 1931 1,930,639 Berthold Oct. 17, 1933 2,175,759 Olson Oct. 10, 1939 2,430,543 Tinnerman Nov. 11, 1947 2,433,358 Garberding Dec. 30, 1947