US2740102A - Electrical connection, method, and apparatus - Google Patents

Description

March 27, 1956 PAULES 2,740,102

ELECTRICAL CONNECTION, METHOD, AND APPARATUS Filed Aug. 25, 1951 TE -may 8 IN V EN TORI ZA /WON 5. 9404 5 ELECTRICAL CONNECTION, APPARATUS Lame Paules, Harrisburg, Pa., assignor to 'oducts Inc, Harrisburg, of New Jersey METHOD, AND

Aircraft- Pa., a corporation This invention relates to electrical connections of the type which are compressively crimped onto a wire or the like, and more particularly to flag-type wire-termination connections and to methods of making them.

Electrical connectors comprised of cylindri-form wiregripping ferrule portions with or without other connecting means such as the ring-like tongues formed on some terminals have been applied to electric wires for some time by compressing (often referred to as crimping or indenting) the ferrule portions onto a conductive wire previously inserted into it. Such compression is usually referred to as pressure-crimping or more simply, as hereinafter, crimping. It is accomplished by compressing a ferrule-and-wire assembly between a pair of die surfaces. With properly shaped die surfaces and adequate compres on, the ferrule-and-wire assembly may be forged that the connection thus made has a tensile strength as great as that of the wire connected, and very low electrical resistance.

30 called flag-type terminals have been standard in electric wiring for a great many years, and in recent years these have been applied by crimping dies; but whereas the ordinary connectors are seam of the ferrule centered in the dies, it has not been possible heretofore with flag-type terminals, because it has always been recognized that the flag must be positioned between the crimping dies. Crimping in this way tends to flatten the ferrule so as to increase its width and to that extent increase the necessary spacing from other conductive parts. Such orientation of the seam, moreover, often subjects it to the most severe stresses during crimping.

Such flag terminals are ordinarily used because of space limitations, since they bring the wire to a binding post, etc, in substantially tangential relation, and it is therefore desirable that the ferrule take up as little room as possible (measured radially of the binding post hole in the side element, which term I use here as a general term for all conducting elements extending laterally from the ferrule portion). Recently in order to permit more compact wiring arrangements without danger of short-circuiting, it has become customary to use insulated ferrules on such terminals. The present invention is applicable with advantage to both insulated and uninsulated flagtype terminals. Such insulated connectors, useful with the present invention, are disclosed and claimed in an application of Trueman R. Bctts, Serial No. 183,615 filed September 15, 1950. Such insulation permits locating terminals in close relation without danger of contact by accidental rotation of the terminal on its binding post, but the insulation itself adds to the over-all diameter of the ferrule, so that such insulating may actually be the limiting factor for very close spacing of terminals which it would otherwise make possible.

it is therefore a major object of this invention to proide means for making a flag-type wire-terminating connection in which the lateral width of the connection (i. e., measured perpendicular to the axis of the ferrule and parallel to the plane of the side element) can be reduced without destroying the mechanical and electrical security of the connections made therewith, and even with enhanced security.

nited States Patent was generally subjected to severe forces prior to and during the crimping In pressure-crimped terminals of the flag-type (i. e., in this specification and claims, all terminals which can be pressure-crimped onto wires and which have a second connecting element disposed to one side of the ferrule portion), a preferred mode of construction the ferrule and the side element formed from a single blank of sheet metal stock, the ferrule portion of the blank being rolled into a cylindrical ferrule in which a wire or other conductor can be received and subsequently ferrule portion. In prior pressure-crimping means for applying such terminals to wires, this scam or abutment which tended to weaken a seam or to separate an abutment.

It is, therefore, a second object of this invention to provide a crimp for, and means for compressively applying this crimp to, flag-type terminals which does not produce such severe seam-weakening or abutment-separating forces.

-It is also an object of this invention to provide a means for fixing the position of a terminal relative to the dies, so that it is secured in position at all times operation.

Furthermore it is an object of this invention to provide a means for impressing a crimp across the seam of a flag type terminal. Prior to the teaching of this invention it was common practice to deform the surfaces at right angles to the seam. This tended to cam the seam open, causing a failure of the terminal. The present invention obviates this condition by causing the deformation to be made across the scam.

I accomplish these objects and gain other advantages by providing a crimping means which has three die surfaces so arranged that they permit clearance of the side element and its joining portion and yet closely abut this element at least during crimping and which are thereby able to compress the material of the wire-gripping ferrule portion, and of its insulation sheath if there is such, wi hout increasing the lateral dimension of the terminal. Further advantages are gained by crimping the ferrule, or ferrule and insulation sheath, into a plane perpendicular to the lateral axis of the terminal, i. e., into a plane perpendicular to the plane of the side element and parallel to the longitudinal axis of the ferrule.

Figure 1 is an isometric view of a typical flag-type terminal.

Figure 2 is a similar view of such a terminal insulated according to the invention of Trueman R. Betts.

Figure 3 is a top plan view of a terminal of the type shown in Figure 2 as it would appear after it has been crimped onto a wire according to old methods.

Figure 4- is a cross-sectional View of a connector of the type shown in Figure 2 while being crimped by opposed crimping dies in a manner which produces a connection as shown in Figure 3; this view can be considered as taken in part at the line 4-4 of Figure 3 and enlarged 50%.

Figure 5 is an isometric view of a terminal of the type shown in Figure 2 after it has been crimped onto a wire according to this invention.

Figure 6 is a top plan view of the connection shown in Figure 5.

Figure 7 is a view similar to Figure 4 but representing the crimping of a connection of the type shown in Figures 5 and 6.

Figure 8 is an isometric view of crimping dies embodying this invention, drawn to the enlarged scale of Figures 4 and 7.

Figure 9 is an isometric view of a terminal of the type shown in Figure 2 after it has been crimped onto a wire according to this invention but with crimping die surface of a different type.

Figure is a cross-sectional view representing the crimping of the connection shown in Figure 9; this figure is analogous to and on the enlarged scale of Figures 4 and 7.

Referring to Figure 1, an illustrative flag-type terminal is shown with a ring-tongue 24 as the side element, this tongue 24 being integrally attached to a metallic ferrule 22. This type of terminal is preferably made by stamping a ferrule and tongue-forming portion, rolling up the former until its edge 25 abuts against the juncture 26 between ferrule and side element 24. in many applications, as where great strength and/ or resistance to the effect of corrosive fiuids is desired, this abutment 26-23 is filled with a sealing and bonding compound, such as hard solder, referred to generally as brazing material. Figure 2 shows this assembly with the-ferrule portion 22 enclosed by a sheath 28 of plastic insulation material according to the above-referred to copending application of Trueman R. Betts.

As there disclosed, the insulation sheath is advantageously extended beyond one end of the ferrule and crimpcd onto the conductor insulation to support the conductor and strengthen the wire against vibration and fiexure. Such an extension is shown in Figure 2 and in Figures 5, 6, and 9 such extensions are shown compressed onto the insulated wire 30 by'means of the advantageous hexagonally-shaped crimp 29 disclosed and claimed in the Carlson Patent No. 2,359,083. Further, the insulation sheath may be cemented to the ferrule to enhance the quality of the assembly.

Prior to the present invention, such flag-type terminals would be crimped onto a wire by compressing their ferrule portions 22 (insulated or bare) between die surfaces in a fashion which flattened the terminal toward the plane of the side element (e. g., tongue 24). An illustrative crimp of this type is shown in Figure 3, wherein an insulated terminal (as shown in Figure 2) has been crimped onto a wire 38 by die surfaces which create D-shaped, curved, impressions 32. This crimp and the method of making it are more fully disclosed and claimed in the Patent No. 2,554,813 issued to Stephen N. Buchanan on May 29, 1951; it is a crimp well adapted to create ferruleand-wire junctions of great strength and electrical and mechanical stability, both on bare as well as crimpablyinsulated terminals. However, when used on flag-type terminals, the die impressions 32 tend to increase the lateral width W by extruding the ferrule (and insulation, f there is such) material laterally outward from the free end of the tongue 24. oftentimes this increase in lateral dimension is restrictive of the use of such terminals, particularly of those with insulation sheath 28. Also as shown in Figure 4, this causes outward extrusion of the seam, 26, tending to cam it open, thus causing terminal failure.

in this application thevarious directions, dimensions and reference planes are designated as follows:

Lateral is the direction in which the width W on Figure 3 is taken.

longitudinal is the direction of the length L on Figure 2.

Vertical is the direction perpendicular to both the lateral and longitudinal dimensions.

Lateral axis is the line through the center of the side element of the terminal perpendicular to the axis of the ferrule portion.

Longitudinal axis is the axis of the ferrule portion of the terminal.

Vertical axis is the line through the center of the ferrule portion perpendicular to the lateral plane.

Lateral plane is the plane common to the lateral and longitudinal axes.

Vertical plane is the plane common to the longitu dinal and vertical axes.

Note the difference between Figure} and Figures 5 and 6, which latter figures show a similar terminal after being crimped according to this invention. A crimp similar to the Buchanan crimp of Figure 3 is used, but the transverse spreading resulting therefrom has been di reted into the vertical plane where it is unobiectionable, because he binding post and nut assembly usually has a height considerably greater than the height of a terminal crimped according to this invention.

Figure 7 shows a preferred embodiment of my inven tion in first, second and third crimping dies 33, 35 and 36 i ectiv 3/ which permit the compacting of the ferrule 22 and insulation sheath 23 toward the vertical plane. Dis 33 and 35 have curved surfaces 37 and of less than half the height of the surface of die 35 in order that the proper crimping relationship of opposed dies may be maintained. During crimping, dies 33 and and die 36 are moved relatively together; dies 33 and 35 are moved in parallel paths toward die 36, or dies 33 and 35 are fixed in position and die 36 is brought toward them, or a combination of these two movements may tel-1e place. in any case, dies 33 and 35 should, upon their surfaces 37 and 39 engaging the sheath 28, be so spaced apart that the tongue portion 24 fits rather closely in between them. Thus die surfaces 37 and 3% can confine the insulation sheath material and press it away from the tongue 24 by virtue of the extrusion normally attendant on thorough crimping. in this instance the extrusion occurs as a slight vertical and longitudinal flowing of the plastic from beneath the crimping die surfaces.

A further advantage of the instant in ention lies inthe relationship of parts that provides a keying effect be tween the terminal and dies. As shown in Figures '7 and 10, the tongue 24 is originally positioned in the slot in one die. This insures proper positioning of the ter .inal relative to the die at all times during the crimping operation. Thus the terminal must be correctly inserted and is retained in the correct position while the crimp is being made.

It is also noted that the teaching of the invention provides a crimp across the seam 26 of the ferrule (Figure 7} rather than at to the seam (Figure 4). Thus the seam is deformed to provide a secure crimp rather than causing it to be split open due to extrusion.

As shown in Figures 3, 5, 6 and 8, the die surfaces of the Buchanan crimp are actually used as reversed duplicate pairs of each surface. The reference to first, second and third die surfaces ignores this duplication, as the latter is not related to the invention but comprises an ad vantageous form of the Buchanan crimping dies.

The closeness of the fit between adjacent edges of the die surfaces 37 and 39 against the tongue portion 24 of a terminal being crirnped is important, as any appreciable clearance might permit some of the insulation material of a crimpably-insulated terminal to extrude outward over the adjacent areas of the tongue portion. This fit should be just loose enough to permit easy insertion and removal of the side element of a connector.

For similar reasons it is important that the dies and 35 are either fixed while the die 36 is moved towar them, or that they are moved so that the adjacent edges of the die surfaces 37 and 359 are maintained closely adjacent to the faces of the tongue portion 24- during crimping; in short, if the side element has parallel faces, surfaces 37 and 39 should be moved in parallel relationship if they are moved at all. An advantageous embodiment is, therefore, that shown in Figure 8 wherein die surfaces 37 and 39, associated with dies 33 and 35 are rigidly held in spaced relationship to one another by the integral attachment of dies 33 and 35 to a Le-bearing member 44. This advantageous, successful embodiment may consist of dies 33 and 35 machined from a single piece of steel, presenting the appearance of Figure 8.

In Figure 10 is shown an embodiment of the present invention which utilizes crimping die features and methods disclosed and claimed by Mr. Clyde N. Holt zapple in application Serial No. 73,946, filed February 1, 1949.

As shown in Figure 10, one of the Holtzapple dies is slotted to receive the side element of a flag terminal. This leaves three smoothly crrved die surfaces, one surface 47 borne on a ram 4-6, the other two in a channellike member 48 having side walls 50 which extend from the curved surfaces 51 and 52 in parallel relationship for short distances away from these surfaces. As shown in Figure 9 this crimp produces a somewhat elongated elliptical band 54 of compressed material in the insulated terminal with substantially no transverse extrusion of this material. The extrusion of the metal ferrule 22 (Figure 1), and insulation material 23 which occurs during crimping is limited, in this cirmp, to a longitudinal flow along the narrow clearance between the ferrule and the die, as the ferrule and insulation sheath are substantially confined about the periphery of the band under compression. The die surfaces 51 and 52 may advantageously be machined from a single block of tool steel.

The above discussions have contemplated the use of flag-type terminals having flat, tongue-like, side elements. However, the invention is not limited to such flat elements, as the clearance between die surfaces 37 and surfaces 39 may be adapted to fit may other side elements, e. g, pin-type or blade-like plugs.

In the embodiment shown in Figure 10, the confinedcrimp dies be of elongated longitudinal extent so that the entire end, or the entire length, of a terminal ferrule and/or insulation sheath would be compressed to the flattened elliptical shape shown in the crirnped area in Figure 9. Such an elongated crimp would be easier to remove from the dies as the sleeve would then be cylindriform, at least clear to one end, and no flared portions of the original sheath dimension would remain to necessitate lifting the crimped terminal from the die. With such dies, the terminal could be merely slid longitudinally out of the female die.

I claim:

1. An electrical flag-type connector comprised of a ferrule portion, an insulation sheath having an aperture therein surrounding said ferrule portion, said ferrule portion and insulation sheath being telescoped over and crimped onto a bare electrical conductor to form a portion of reduced width, said ferrule portion having a side element comprising a flat tongue projecting radially thererorn through the aperture in said insulation sheath, the

resulting body formed by the crimped ferrule portion and conductor as viewed in a cross section passing through the side element presenting roughly an elliptical shape, the long axis of said elliptical shape extending in a direction perpendicular to the plane of the tongue, and with the insulation sheath forming roughly an elongated elliptical band around said elliptical shape.

2. An electrical connector and conductor including: a seamed metal ferrule encased in an insulating sleeve and having one end open to receive the conductor, an aperture in said insulating sleeve, tongue extending radially from the ferrule adjacent to the seam through the aperture in the insulating sleeve, the ferrule being deformed onto the conductor at right angles to the tongue on each side along the line of contact with the tongue and across the seam so that the ferrule has the minimum width at this junction.

3. An electrical connector secured to a conductor which includes: a longitudinally seamed metal ferrule deformed ontoa conductor, a tongue extending radially from the surface of the ferrule adjacent the seam of the ferrule, an insulating sleeve surrounding the ferrule with a slit therein to permit the tongue to extend therethrough, one end of the insulating sleeve being sealed, the conductor extending into the ferrule through the open end of the sleeve, the ferrule and sleeve deformed onto the conductor substantially perpendicularly to the tongue so that the tongue extends from the ferrule in juxtaposition to the narrowest width of the deformed ferrule across the seam of the ferrule.

4. An electrical flag-type connector comprised of a ferrule portion telescoped over and crimped onto a bare electrical conductor to form a portion of reduced width with a flat tongue radially connected to said ferrule and projecting laterally therefrom, the resulting boy formed by the crimped ferrule portion and conductor as viewed in a cross section passing through the flat tongue presenting a generally elliptical shape, the major axis of said elliptical shape extending in a direction perpendicular to the plane of the tongue.

5. A die means for crimping a flag-type connector including: a first die member substantially U-shaped in cross-section whereby an arcuate portion is formed on one die surface, a second die member slidable within the first die member and having an arcuate, concave, die surface, and a transverse slot in one of the die surfaces, for engaging the tongue of the flag-type connector to key the connector to the die surface prior to and during the crimping operation.

6. Die means for crimping an electrical connector having a tongue thereon including a plurality of die surfaces cooperable to deform the connector and means integral with one of the die surfaces for holding the connector relative to the die surfaces, prior to and during the crimping operation, said means comprised of a slot in the die surface which accommodates the tongue on the connector to position properly the connector relative to the die surface.

7. The method of securing a longitudinally welded, seamed connector, of the type having a tongue extending radially from the surface of a ferrule adjacent to the seam, to a conductor including: positioning the connector between a plurality of dies of the tongue to deform the connector onto a conductor substantially at a right angle to the tongue whereby the connector is fixed in relationship to the dies, at all times during the crimping operation.

8. The method of claim 7 wherein the ferrule is deformed across the seam of the connector by urging the dies toward each other in a crimping direction corresponding to the plane defined by the tongue.

9. The method as set forth in claim 7, wherein the ferrule of the connector is surrounded by a sheath of deformable plastic with the tongue protruding there through and the connector is deformed onto the conductor by applying the crimping pressure to the outer surface of the deformable plastic sheath.

10. The method of making a connection between a conductor and a flag type, longitudinally welded, seamed, connector having a ferrule and a tongue extending radially from the ferrule adjacent to the seam including the steps of (l) inserting the conductor into the ferrule and (2) forging said ferrule and conductor together by pressure directed parallel to and equally disposed on each side of said tongue as well as simultaneously directing pressure to the area diametrically opposed thereto so that the deformation occurs across the seam substantially perperpendicular to the tongue.

References Cited in the lile of this patent UNITED STATES PATENTS

Images