US2165323A - Terminal for electrical conductors - Google Patents

Description

July ll, 1939. J. M. WHITE TERMINAL FQR ELECTRICAL CONDUCTORS Filed Aug. 11, 1938 1; Patented July 11, 1939 UNITED STATES 2,165,223 TERMINAL roa announcer. commo'rons PATENT OFFICE 'Jesse'uwmte, Philadelphia, Pa.

Application August 11, 1938, Serial No. 224,294

j 2 Claims. 01. 173-269) This invention relates to terminal s for electrical conductors and is concerned primarily with trical conductors having terminals afiixed to their extremities is becoming more and more widespread, particularly throughout the automotive industry, in that the manufacture of every motor minal prise a nose and neck,through which extend a vehicle involves a. large number of detachable connections, the connections usually consisting of a socket in which is receiveda terminal that is aflixed to the extremity of the conductor. Due to the fact that every time the connection is to bebroken a pull is exerted on the conductor there is a grave tendency for the connection between the terminal and the conductor to be-destr oyed, and this tendency has been harmfully felt in the automotive field under conditions of actual service usage, and now known methods of amxing '25 the terminals to the conductors.

From the viewpoint of holding to a minimum the cost of assembling the terminals on the conductors it is well recognized that the most desirable method of. affixing the terminals on the conduct'ors'is by so-called crimping operations, which involve a simultaneous deforming of the metal of the terminal and the conductor therewithin; H

However, the now known methods of carrying-out these crimping operations the bond which is effected 'thereby-hasbeen of .such character as not to withstand service usage and maintain; at the-same time, goodmechanical bond and. the required conductive connection between 40 the terminal and the conductor. I

'I'heanufact rs of motor VGhiClQS have 2. found it o'be necessary to supplementthe now known methods of crimping by soldering operantions, inorder to provide such a'connection between the terminals and the conductors which.

will-stand up satisfactor'ily'over prolonged periods of service usage. However, this supplemental soldering is extremely undesirable from the as-' pect of'increased cost.

so With the foregoing conditions i mind this it vention has in view, as its foremost objective, the: provision of a. terminal which is crimped to a conductor in sucha manner as to provide at the as and a good conductive connection, both of wine same time a highly efiective mechanical.

elements are maintained during prolonged periods of service usage without being supplemented by any soldering or other processes.

The insulated electrical conductors of the type with which this invention is primarily concerned, and which are meeting with widespread use in the automotive field, consist ofthe conductor proper defined by a plurality of strands which are twisted in a well-known manner and which are covered by the insulation. The insulation is stripped back from the end of each conductor a required distance to provide for the mounting of the terthereon, The terminals ordinarily comcylindrical bore which is adapted to receive the stranded conductor, and a skirt having an enlarged bore which receives the insulation.

In order t render practical the assembling of the terminals on the conductors it is necessary that the stranded conductor be readily inserted in the smaller bore extending through the nose and neck. As a general rule the conductor has a smaller diameter than the bore to permit of this required ready insertion. With the stranded conductor positioned in the bore it has been the practice to crimp the terminalto the conducton by subjecting the terminal and conductor therewithin to the efiects of deforming instrumentali ties, such as radially moving crimping jaws which heretofore have served to decrease both the cross sectional area of the bore of the terminal as well as the contact" surface between the bore and the conductor,

Incarrying' out the above noted objective this invention contemplates a departure from this known practice by providing for a decrease in the cross sectional area of the bore at the zone of crimping, at the same time maintaining con- .stant or increasing the contact surface between the conductor and the bore of the terminal.

The heretofore prevalent practice of crimping the terminal to the conductor by decreasing'the cross sectional area of the bore of the terminal so as to crowd the strands ofthe conductor together, with a tendency to more or less fuse the same into a solid cross section, has also been characterized by a reduction in the maximum cross sectionahdilgl ension of the conductor. The presentirWentibn also contemplates aradical departure from this condition by providing for an increase in the maximumcross sectional dimension'o'f the stranded conductor over its original diameter, rather than any decrease, thus" pro-- vlding for enlargements ,of portions of the conductor within the bore of the terminal, which. afford a good mechanical bond.

An important part of my invention is the discovery that this desired action on the part of the metal of the terminal and the conductor may be obtained by crimping the terminal at exact- 1y three points equi-angularly spaced about theterminal, the crimpings being formed by radially moving jaws in a manner well-known in this art.

The invention, therefore,' has in view, as an important object, the provision of a terminal which is crimped to an electrical conductor at exactly three points equi-angularly spaced thereabout.

In view of the use to which the terminal is to be put; namely the insertion thereof into a socket to establish a detachable connection, it is important that the terminal maintain substantially its original formation after crimping operations,- and the invention, therefore, has in view, as a further objective, the provision of a terminal which is crimped to an electrical conductor and which maintains substantially its original circular formation at the zone of crimping. This objective is maintained by deforming only substantially 50 per cent of the circumferential extent of the terminal at the zone of crimping.

It is evident that if the reduction of the cross sectional area of the terminal'at the zone of crimping is carried too far the conductorwill be substantially severed, or so weakened as to be unable to stand any appreciable stress. There is, therefore, a'limit to which this reduction in cross sectional area may be carried. I

Recognizing that under certain conditions the attainment of this limit will still not provide a mechanical bond of such character as will withstand service usage, the invention has in view, as a further objective, the provision of a terminal which is crimped to an electrical conductor at Thusthe mechanical bond at one The invention has in view, as a further objective, 'the provision of a terminal includinga nose, and a neck through which extends a cylindrical bore that receives an electrical conductor,

with the terminal being crimped to the conductor at one ,zone which is located substantially at the extremity of the nose, and at another zone which is located at the neck. Y

Due to the fact that the reduction of cross sectional area of the electrical conductor at the extremity of the nose is not of so much importance it has been found entirely practical to increase the number of crimpings at the zone in the nose.

Accordingly, the invention has in view, as a further objective, the provision of an electrical terminal which is mounted on a conductor in the manner above described, and in which there are a larger number of crimpings in the nose than in the neck, and still more in detail a further ob-- jective is the provisionof an arrangement in' which the number of crimpings in the nose is substantially twice the number Oft p the neck. I

These and various other detailed objects and advantages such as arise in connection with carrying out the above noted thoughts in a practical embodiment will in part become apparent,, and in part be hereinafter stated, as the description of the invention proceeds. 2

The invention, therefore, comprises an electrical terminal including a nose and neck through which extends a. cylindrical bore that receives the stripped extremity of an insulated electrical conductor, the terminal being deformed at its neck by three crimpings equi-angularly spaced about the terminal to decrease the cross sectional area of the bore thereof, at the same time increasing the surface contact between the bore of the terminal and the conductor, the metal of the terminal also being crimped to the conductor at a zone substantially at theextremity of the nose,

' there being twice as many crimps in the nose a in the neck.

For a full and more complete understanding of the invention reference may be had to the following description and accompanying drawings, wherein Figure 1 is a side view partly in section and partly in elevation, showing a terminal applied to an electrical conductor prior to the crimping thereto,

Figure 2-is a side view somewhat similar to Figure 1, but showing a terminal in elevation,

Figure 3 is another side elevational showing developing the terminal after'the crimping operations have been carried out,

Figure 4 is an end elevational showing taken about on the plane represented by the line 44 of Figure 3,

Figure 5 is a cross section taken about on the plane represented by the line 55 of Figure 3,.

and

Figure 6 is another cross section taken about on the plane represented by the line 6--6 of ductor of the type illustrated, as it is such conductcrs as thes which are meeting with widespread use in th I automotive field. However, the invention is not to be strictly limited in this respect as it is susceptible of being utilized to great advantage with solid conductors. It will be noted that-the insulation H is stripped back from the egrtremity of the conductor l0, leaving the section at the end thereof bare.

A terminal is referred to in its entirety by the reference character B, and is made from a. good conductive metal as is well known to those skilled 1n this art. This terminal B ordinarily includes anose-like end portion designated l2, and a skirt I3 which fits over the insulation I l. Between the nose l2 and skirt [3 is a neck It which may include a groove l5 that functions to establish the detachable connection with the socket in which the terminal is inserted. Extending throughout the nose l2- and neck I4 is a bore lfiwhich is enlarged. in the skirt l3, as shown at H.

Following the usual practice in this art the conductor 10 will have a diameter appreciably 1 With the stranded conductor l fitted in the bore l6, and the insulation II in the bore ll -of the skirt [3, as depicted in Figure 1, a suitable crimping machine, such as that illustrated and described in the patent to White, No. 2,114,159, may be availed of to simultaneously crimp the terminal to the conductor at zones located in the nose l2 and neck ll respectively, and also to crimp the skirt l3 to the insulation ll.

Referring more particularly to Figures 3 and 5, i

it will be noted that the crimps in the neck I are three in number, and designated l8. These crimps I8 are equi-angularly spaced apart about the neck I4 and are so dimensioned as to. leavesubstantially undisturbed per cent of the circumferential extent of the neck M. The formatween the conductor l0 and the inner wall of the neck It remains at least substantially constant, or is increased, which is the usual easel" It is also important to note that the points designated is, which were originally on-the bore i6 of the neck fll, move inwardly a maximum'distance, while other points such as designated 20 remain substantially stationary or perhaps move slightly outwardly.

. Extending between the points l9 and 20 are I surfaces identified at 2i, and this inner movement off thepoints l9 causes the strands of the conductor-Ill to be squeezed between the surfaces 2|, and this squeezing action is particularly enhanced closely adjacent to the points 20 due to well-known physical rules of mechanical advantage.

It is also notable that the circular formation originallyfassumed' y the stranded conductor Ill has been materia y changed and that the cross section of the stranded conductor gvhich is shown in Figure 5 presents a marrimumdiin'ension which a the cross sectional area defined by the wall ofis in excess of the originaldiameter of the stranded conductor III. This change'in the shape of the metallic structure of the conductor 1-" pre-- sents a structure comparable to a riveted joint in that the deformed'portion within the crimps I! of the neck I are constituted the equivalen of a riveted end.

Referring now more particularly to Figures 3 and 4, it will benoted that the metal of the terminal at the extremity of the nose I2 is deformed by aplurality of crimps designated 22,

which, in the illustrated embodiment,'are six in number. There is a c'ertain definite relationship between the presence and number of the crimps- 22 in'the nose I2 and the crimps II in the neck I.

In the first place, the formation of the crimps II inthe neck I4 is attended by a limit to which the here It may be reduced, as a reduction past this limit would either sever the stranded structure II, or so weaken the same as to render it incapable of withstanding appreciable stress.

I ,this condition is notpresent in forming the crimps 22 at the end of the nose l2. Moreover it is notable that it is the nose l2 which while providing forfan effective connection at this zone still leaves undisturbed the shape of the nose. This deformation of the metal of the stranded conductor i0 involves a. certain, though small, amount of longitudinal flow of the metal,

and this longitudinal fiow cooperates with alongitudinal flow in an opposite direction that isset up by'the formation of the crimps i8, whereby the mechanical bond and conductive connection afforded at eachzone of crimping is greatly enhanced.

As shown in Figures 3 and 6, still another series of crimps designated 23 may be formed in the skirt I3, and these crimps serve to crimp this skirt l3 to the insulation ll.

While a preferred specific embodiment of the comprising insulated metallic conductor means and a grooved sleeve in which a bare end of said conductor means is disposed; a skirt provided on said sleeve receiving the insulation in a manner to provide, an annular space between the skirt and the insulation; said conductor means and said sleeve being swaged into a solid-metal crosssection in a predetermined transverse general plane on oneslde of said groove; said'conductor. means and'said sleeve also being swaged into a continuous solid-metal cross-section in a predetermined transverse general plane on the other side of said groove; and said skirt being crimped to bring the sleeve and insulation on the' con-v ductor into bearing relation whereby to close said-annular space and seal from the atmosphereat least one-of said swaging'planes.

2. The combination of an electrical fitting with a metallic electrical conductor, comprising a metallic sleeve having two longitudinally aligned bores of different transverse dimensions and external means adapted to cooperate with a hold-' ing member of a sliding friction-type connector,

'a-metallic electrical conductor carrying insula: tion through part of its length and exposing a bare portion and having the bare portion of said said hora of said sleeveand the insulated por tion inserted in the larger of said bores of said sleeve, a plurality of longitudinally spaced crimpings formed in. said sleeve and metallic condw tor to join said sleeve and conductor and swase the metal of said sleeve and conductor into. a continuous solid metal cross-section at the location of said crimpinss, and. 'crimpings formed in said sleeve and insulation carried by said metallic electrical conductor so as to gripsald insulation electrical conductor arranged, in the smaller of

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