US2749529A - Insulated flag-type terminal - Google Patents

Description

June 1956 L. M. CURTISS INSULATED FLAG-TYPE TERMINAL Filed March 27, 1955 w I I I I I,

INVENTOR. LAWRENCE M. CURTISS ls\\\\\\\\\\\\\\\\\ IIIIIIIIII QTTORNEY WSULATED FLAG-TYPE TERIWINAL Lawrence M. Cnrtiss, Mountainside, N. 5., assignor to The Thomas & Betts Co., Elizabeth, N. 3., a corporw tion of New Jersey Application March 27, 1953, Serial No. 344,926

Claims. (Cl. 339-223) The invention relates in general to a shielded cable terminal of the flag type, and specifically relates to such a terminal which includes a metallic barrel intended to receive an insulated cable, and which barrel is contained in a shield and is designed to be deformed conventionally by squeeze pressure applied through the shield into a crimped engagement with the bare ends of the cable conductors within the barrel.

The primary object of the invention is to provide such a terminal as an article of manufacture with an insulating shield already in place and which will protect the barrel and at the same time leave fully exposed for attachment to other conductive articles the outstanding integral tang which forms an integral part of flag-type connectors.

Broadly, this objective is attained by premolding a shield of insulating elastic plastic material, one end of which constitutes a cylinder within which a barrel element of the metallic flag terminal may be received and by providing the outlining wall of the cylinder with a slot-like opening through which the tang can extend when its barrel is in its prelocated place in the cylinder end of the shield.

Still another object of the invention is to provide a form of insulating shield which with its metal barrel in position will tend to avoid, or at least to minimize, the infiltration of dust into its interior and thus minimize the presence of foreign matter in the finally formed terminal.

The invention in the forms illustrated contemplates forming the shield with a tubular extension at one end to form a reinforcing skirt for embracing and protecting the insulating jacket of the cable or cables in the parts thereof adjacent the bared conductor ends.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of three forms of flag-type cable terminal each embodying the invention, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the drawings:

Fig. 1 is a top plan view looking down on a shielded cable terminal of the flag-type constituting a preferred embodiment of the invention particularly designed to receive an end of a cable and with parts broken out at one end to show internal construction;

Figs. 2 and 3 are sectional views taken, respectively, on the lines 22 and 3-3 of Fig. 1, in each case looking in the direction indicated by the arrows;

Fig. 4 is a view in axial section of the shielded terminal of the preceding figures taken on the line 44 of Fig. 2 and secured to the end of a cable;

Figs. 5-7 are views of a first modified form of the invention designed to receive the end of a cable and in which Fig. 5 is a longitudinal axial sectional view taken on the line 5-5 of Fig. 6 and with an end of a cable crimped in place; Fig. 6 is a transverse sectional view taken on the line 6-6 of Fig. 5 after the cable has been 2,749,529 Patented June 5, 1956 ice inserted therein and the barrel crimped onto the bare cable ends; and Fig. 7 is a right end view of the terminal of Fig. 5 before the cable is inserted therein;

Fig. 8 is a view in side elevation of a second modified form of shield aspect of the invention, showing a flap form of closure for the opening prior to the insertion therein of the tanged barrel; and

Fig. 9 is a transverse sectional view taken on the line $-9 of Fig. 8, and with the flap momentarily held in its open position.

In the drawings and referring first to the disclosure in Figs. l3, there is shown an article of manufacture comprisirn solely two parts, a metallic connector it) of a flag-type and a preformed insulating shield 11 of an insulating plastic material for enclosing and thus protecting the barrel part of the connector.

The connector is of somewhat conventional form and comprises a strip of conductive metal, in this case, sheet copper, with one end rolled back upon the strip to form an open-end barrel 12, leaving the balance of the strip flat to form a tang or tongue 13 extending tangentially away from the barrel. As usual, the tang is provided with an aperture 14 and is otherwise designed to provide an electric contact with some other conductive object, as is usual with flag-type connectors.

The shield i1 is formed of a plastic, non-conductive and heat-resistant material and having at least some degree of plastic memory. In the case illustrated the shield is formed of a synthetic condensation polymeric amide manufactured by the E. I. du Pont de Nemours & Co. under the designation of nylon and one form of which is disclosed in the patent to Gordon, No. 2,348,536, granted May 9, 1949.

The shield is premolded to shape, is of one-piece, of tubular form, and one end forms a cylinder 15 and its other end forms a skirt 16, with the bores of the cylinder and skirt coaxially related. The end of the cylinder opposite the skirt is closed by an end wall 17 which acts to provide an internal brace t0 the cylinder at its closed end.

The portion of the bore of the cylinder in which the barrel l2 fits is of a slightly larger diameter than the bore of the skirt to form an internal stop shoulder 18 operative to defeat axial shifting of the barrel in a direction towards the skirt. The end wall 17 acts as a stop to defeat movement of the barrel in the opposite axial direction as shown in Fig. 4. In this way the barrel 12 is fitted into an annular groove formed in the bore of the shield between the shoulder 18 and the end wall 17.

The diameter of the groove so formed in the cylinder bore is dimensioned to receive the barrel with a snug fit and the diameter of the skirt bore is dimensioned to provide a snug fit with the insulating jacket B of the cable A hereinafter described.

it is a particular feature of this disclosure that the wall of the cylinder is provided with an elongated slot-like opening 19 extending parallel to its longitudinal axis and dimensioned to permit the tang 13 to extend therethrough with a close fit therein to close the opening.

in the devices illustrated, where the shield is made of a plastic material as indicated, the internal diameter of the cylinder is molded slightly less than the external diameter of the barrel which it is intended to embrace so that, as the shield tends to shrink back to its molded configuration, it tends to bind the cylinder frictionally on the barrel.

In mounting the barrel in place in the shield it is an approved practice to stretch the plastic cylinder radially at the opening 19, sufliciently to permit the barrel to be passed sidewise therethrough and located within the cylinder between the stop shoulder 18 and the end wall 1'7,

leaving the tang outside of the shield and then releasing the clistending stretching forces to permit the shield by reason of its plastic memory to return automatically to its initial molded configuration in a squeeze binding engagement with the barrel. In this way the cylinder 15' at all i res restores itself thereby engaging and clamping itself snugly to the barrel.

In the finished article the tang extends in a plane substantially tangent to one side of the cylinder 15, as best shown in Fig. 2.

The shielded flag-type terminal as thus formed constitues a complete article of manufacture and is so placed on the market, ready to have the stripped-back end of a cable inserted therein.

A right or left-handed terminal can be fabricated selectively from the parts herein disclosed, depending on the tr e connector is inserted into the barrel of the pie ,ic shield.

The connector so formed is utilized to form a flag terminal to an. electric cable, for instance, as illustrated in Fig. 4. in this case there is shown a cable A of the aircraft type with an insulating jacket B which is stripped back f om one end to expose a bundle C of strand con- The cable is inserted with its bare conductors in advance, successively through the bore of the skirt and then through the cylindrical bore of the barrel until stopped by the conductors contacting the end wall 17. The barrel is then deformed transversely with an indentation E extending from the upper side laterally onto the bundle of conductors by a squeeze pressure applied to the barrel through the insulatin cylinder along the line indicated by the arrow in Fig. 4 and as more fully described in the co- 'rding application of John Nelson Frey, Serial No.

,;62, filed June 26, 195i.

By means of the form of plastic preformed insulator disclosed there is provided maximum insulation around both the terminal and the adjacent portion of the cable insulation with the least possible use of insulating material and disposed in close relation to the barrel to prevent the nfiltration of foreign matter into the cable terminal. The 5 1g fit of the skirt end of the shield over the cable insulation jacket B grips and supports the same and prevents the end of the cable insulation from fraying. The shirt is of annular form, externally tapering to a nose at its free end and. of greatest cross section of material at the shoulder The portion forming the shoulder 18 is of maximum cross section of material and this tends to reinforce the slotted tubular portion. In this case the skirt hugs the jacket B frictionaily.

it is suggested that in those cases where it is desired for any reason to extend the bundle of connectors through and beyond the terminal a hole he provided in the center of the end Wall 3.7 of sufficient diameter to permit the conductors to pass therethrough, leaving the marginal portion of the closure 17 as an. annular flange to form an abutment against which the adjacent end of the barrel 12 may engage.

Referring specifically to the first modified form of the invention illustrated in Figs. 5-7, the end portion 28 of the plastic shield, which receives the cable, is enlarged over the portion which receives the barrel 12. The bore of the end portion 20 is twice reduced to form an outer thin-walled sleeve 21 of relatively small cross section of al and an inner thick-walled sleeve 22 of greater cross section of material. The end of the inner sleeve at its cable-receiving end is beveled inwardly to form a It is understood that the Figs. 5-7 form of the invention may be utilized to receive a diiferent form of cable than is shown in Fig. 5 The bore 26 of the outer sleeve 25. is dimensioned to receive the insulating jacket of a cable with a sliding fit. In such case the beveled end can act as a stop to limit the intrusion of the insulation jacket and with it the intrusion of the cable end into the fitting.

in this form of the shield, the opening 25 for receiving the barrel 12 is of greater arc length than is the corremat rial length of the barrel l2 exposed as shown at 27 for receiving an indentation H for crimping the barrel onto the bare ends of conductors received in its bore, as shown in 6. Under certain circumstances, the free end of the barrel 12 may be welded to the tang 13 along the iointure 28, thus defeating any tendency of the tang a sting from the barrel, incident to the operation of running the indent H. In this way the metal barrel may be crimped onto the bare ends of the conductors by pressure applied directly to the barrel along a squeeze line approximately along the section line S-5 of Fig. 6, and thus the plastic shield need not become involved in any way in the crimping operation.

Rer'e rig to the second modification of the shield elemerit of the disclosure, the end portion which is to receive the barrel is slit along spaced-apart parallel lines and transversely of the molded shield from the opening 15.9 for about eighty-five degrees arc length to form narrow slots 33$ and 39. The slots are spaced apart a distance to permit the insertion into the shield of the barrel 12 as previously described. The portion of the shield between. the slots forms a flap-like closure 31 connected along the hinge line 32 to the balance of the shield. In operation, the closure 31 is elevated as shown in Fig. 9 to enlarge the opening 1') and through this enlarged opening the barrel may be freely inserted sidewise as previously described for the insertion of barrel 12 through the smaller size opening 19. When released the closure returns elastically to its closed position, leaving the opening it? as shown in Fig. 8 and no wider than is necessary accommodate the extension therethrough of the tang shown in Pig. 2. In this case, the barrel may be held in the shield, even ignoring its frictional engagement therewith and ignoring the closure 31, by reason of the fact that the shield encloses the barrel for more than a half circle, that is, for an arc distance of about 237 degrees, as viewed in Fig. 9.

Moreover, the skirt id be omitted but its presence does tend to reinforce the cylindrical portion provided with the slotted opening 15 The disclosure particularly features economy in manufacturing cost. The shield can be molded as a one-piece article by conventional molding processes, and the metal connector likewise can be formed by standard practices. The barrel element of the connector can be passed through the side opening in the shield by unskilled labor and with the assurance that the parts will fit exactly as intended and with the bar cable end inserted the unit so preferomed may be subjected to conventional crimping practices to secure the flag-type terminal to the cable.

I claim:

1. A terminal fitting including a preformed molded shield of insulating material having an axially extending bore and forming at one end a tubular portion fashioned to receive the metal barrel of a connector, said tubular portion provided along one side thereof with an axially extending opening through which the metal barrel may be inserted sidewise, the bore at its other end being twice reduced to form an inner sleeve spaced from both ends of the shield, and an outer sleeve defining a cable inlet for the shield, and the inner sleeve at its end nearest the outer sleeve being beveled to form a funnel-like entrance opening from the portion of the bore encircled by the outer sleeve into the portion of the bore encircled by the inner sleeve.

2. A terminal including an inner cylindrical metal barrel having a bore fashioned to receive wire conductors, a shield of insulating material having a bore in which the metal barrel is at least partially contained, said shield provided along one side with an opening through which the metal barrel is passed sideways, a part of the barrel being exposed through the opening to provide an area adapted to be deformed by crimping apparatus into a binding engagement with conductors in the bore of the barrel without involving the shield in the crimping operation.

3. A terminal for an electrical conductor comprising the combination with a cylindrical metal barrel having a bore for receiving an end of said conductor and adapted to be crimped into binding engagement with said conductor end; of an insulating container for said barrel comprising, a sleeve of resilient insulating material having a length substantially greater than said barrel and an inner diameter substantially equal to the diameter of said barrel and having at one side a window-like opening longitudinally dimensioned to permit passage of the ends of said barrel between the ends of said opening and transversely dimensioned to permit forced passage of the side walls of said barrel between the sides of said opening by momentary deflection of its longitudinal edges; said opening thereby permitting forced sidewise entry of said barrel to contained position therein and thereupon leaving exposed an area of said barrel for indentation by crimping apparatus into binding engagement with said conductor end.

4. A terminal for an electrical conductor comprising the combination with a cylindrical metal barrel having a bore for receiving an end of said conductor and adapted to be crimped into binding engagement with said conductor end; of an insulating container for said barrel comprising a cup-like sleeve of resilient insulating material having a length substantially greater than said barrel and an inner diameter substantially equal to the di ameter of said barrel, said sleeve having at one side a window-like opening extending longitudinally from its closed end to a dimension to permit passage of the ends of said barrel between the ends of said opening and transversely dimensioned to permit forced passage of the side walls of said barrel between the sides of said opening by momentary deflection of its longitudinal edges, said opening thereby permitting forced sidewise entry of said barrel to contained position therein and thereupon leaving exposed an area of said barrel for indentation by crimping apparatus into binding engagement with said conductor end.

5. An insulated flag-type terminal connector for an insulated electrical conductor including an inner metallic barrel portion having an opening therethrough for the intrusion therein of a bare end portion of said conductor, comprising an insulating shield in the form of a hollow cylinder of resilient plastic material closed at one end thereof and having a length substantially greater than said barrel portion and an internal diameter substantially equal to the diameter of said barrel portion, said cylinder having an elongated opening therein extending from its closed end through an arc of the periphery of said cylinder on -a chord measured by said are whereby the longitudinal and transverse dimension of said opening is such as to permit said barrel portion to be forceably inserted through said opening into said cylinder with the opposite end faces of said barrel portion in abutment respectively with the partially closed end of said cylinder and the opposite end of said opening intermediate the ends of said cylinder, and with an insulated portion of said conductor, adjacent said bare end portion, extending into the annular open end of said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 422,058 Mclntire Feb. 25, 1890 1,315,135 Rocco Sept. 2, 1919 1,946,713 Rowley Feb. 13, 1934 1,967,014 Taverner July 17, 1934 2,146,612 Alden Feb. 7, 1939 2,289,512 McKenney July 14, 1942 2,623,085 Gier Dec. 23, 1952 2,701,273 Badeau Feb. 1, 1955

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