US 2804602 A
Description (OCR text may contain errors)
A g- 7, 1957 R. J. VIZCARRONDO 2,894,692
ELECTRICAL. CONNECTORS Filed Jan. 21, 1.954
IIVVENTOR oberc J. lizcarrondo 4 M M. \A uflmqk United States Patent ice ELECTRICAL CONNECTORS Robert John Vizcarrondo, Camp Hill, Pa., assignor to AMP Incorporated, a corporation of New Jersey Application January 21, 1954, Serial No. 405,382
1 Claims. (Cl. 339-276) This invention concerns an electrical wiring construction wherein an electrical conductor, such as a wire, is made ready for electrical contact with many types of other electrical devices.
More particularly, this invention contains the idea of supporting and insulating an electrical terminal. Supporting and insulating materials are aflixed to the electrical terminal in a way so as not to interfere with the normal functions of the terminal. Supporting and insulating bodies of a given size may be used with most types of electrical connections of that size.
In the particular embodiment of this invention which is described below, the insulating body is in the shape of a tubular plastic sleeve while the supporting body is composed of a metal tubular sleeve which is permanently fixed inside the plastic sleeve to form a composite sleeve and the electrical terminal about which this composite sleeve is fastened is a receptacle for a plug. There is sometimes a tendency for the male plug to deform the receptacle when the connecting members are subjected to improper assembly or when a conductor is given a lateral pull. Such treatment is likely to loosen the connection and sometimes stress on the wire will cause the connection to come apart. This invention provides a supporting and insulating cover for the terminal that prevents destructive deformation, is easily applied, insulates the connection, yet allows free insertion and removal of the male plug.
In this specification and the accompanying drawings I have shown and described a preferred embodiment of my invention and various modifications thereof; but it is to be understood that these are not intended to be exhaustive nor limiting of the invention but, on the contrary, are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify and adapt it in various forms, each as may be best suited to the conditions of a particular use.
For a more complete description of this particular embodiment of my invention, reference will be had to the drawings in which:
Figure 1 represents a plastic and metal sleeve with a section cut away;
Figure 2 shows the receptacle on the end of a conductor;
Figure 3 is a perspective view of the composite sleeve crimped onto the receptacle; and
Figure 4 is a perspective, cut away view of the composite sleeve crimped onto the receptacle.
In Figure l, a plastic sleeve 21 is shown in place over an inner metal sleeve 22, the two being permanently joined to form a composite sleeve. The cut away section shows the length of the metal sleeve and its folded in portion 23 which strengthens the sleeve and provides a preferred edge. As shown the wall thicknesses of sleeves 21 and 22 are about equal but in practice the plastic sleeve commonly may be as much as several times 2,804,602 Patented Aug. 27, 1957 as thick as the metal sleeve. Figure 3 shows the composite sleeve mechanically secured around a terminal 26 by a crimping operation. The sleeve should be positioned in relation to the terminal so that one end extends beyond the free end of the terminal a suitable distance, enough to insure insulation and also enough to support and protect the margins which define the opening into the receptacle. The sleeve does not fit so tightly about the receptacle walls as to prohibit any normal flexing but leaves a small annular clearance region. The sleeve is close enough to the receptacle walls to offer support before the elastic limit of the walls is reached. This greatly enhances the value of the terminal, giving it greater application, and solving the problem created by frequent failure of previously known plug and receptacle connections. With the sleeve of this invention present, even if the plug terminal is subject to sudden thrusts or is improperly inserted it will be substantially impossible for it to deform the female member beyond its elastic limits.
As is shown in the drawings, the femal receptacle 25 is split longitudinally along the barrel as at 27 to permit the barrel to expand slightly when receiving a male plug member. Thus the metal sleeve 22 acts as a container to prevent the over-expansion of the female receptacle, due to careless insertion of the plug, or other causes. Without the metal sleeve 22 the female receptacle 25 mightbe permanently deformed and would no longer serve to hold a male plug.
As is evident from the drawings (see Figure 2) the inner end of the female receptacle 25 is crimped onto the bare end 30 of insulated conductor 32. The particular female receptacle shown has a ferrule 26 adapted to receive a plug member and reduced portions 34 and 36 for securing the female receptacle to the bare end of the conductor and the conductor-insulation respectively. While the illustrated embodiment is the preferred form it is understood that other types of female receptacles may be employed. However, there is advantageously a reduced portion between the female receptacle and the conductor so that the metal sleeve 22 may be crimped in the region behind the female receptacle. Of course other methods of attaching the female receptacle 25 to the conductor will readily occur to anyone skilled in the art. For example, a bayonet slot and key arrangement could be provided between the sleeve 22 and the receptacle 25. The only requirement is that the ferrule 26 is permitted to expand when embracing the plug member but is prevented from over-expansion by the rigid sleeve.
In assembly the female receptacle is inserted longitudinally into the composite sleeve. The inner end of the metal sleeve 22 is crimped at 38 (Figure 4) behind the ferrule 26 and the plastic sleeve 21 is crimped at 40 in the region of the conductor insulation.
The end of the composite sleeve from which the wire protrudes extends beyond the terminal and over the wire so that when the wire is subjected to vibrations and other fluctuating forces, the point of bending will not be at the junction of the end of the terminal and wire where the wire may already be under a stress but will be at that area where the sleeve ends, where there is no previous wire stress, thereby giving better protection against wire failure. This assists in keeping the insulation in an unfrayed condition as Well as protecting the wire.
The indentation of the crimp which binds the composite sleeve to the terminal is so placed that it forces the sleeve down between the receptacle barrel and ferrule portions of the terminal at notch 28. This does not disturb the ferrule portion and leaves the holding qualities of the terminal the same as they were before. Metal sleeve 22 is positioned within plastic sleeve 21 so that folded in portion 23 will be crimped into notch 28, providing a secure mechanical bond. The portion of'the plastic sleeve which is not lined with metal is used pri- I marily for insulation and protecting the wire insulation and wire near the terminal. The metal sleeve may be extended toward the end of the plastic sleeve if desired.
In this specification and the accompanying drawings, although I have shown and described several preferred embodiments of my invention and various application thereof, these are intended to be illustrative in order that those skilled in the art may fully understand the invention and principles thereof, and the manner of applying it in practical use so that they may modify and adapt it in various forms, each best suited to the conditions of a particular application.
An insulated, electrical connector, adapted to be crimped onto a conductor including: an expandable cylindrical, metal receptacle, one end of which is crimped onto the conductor, a metal ferrule of slightly larger diameter than the receptacle and concentric therewith, one end of said ferrule being secured to the receptacle in the area of the crimped connection between the receptacle and the conductor, the other end of the ferrule spaced circumferentially from the receptacle, and an electrical insulating sleeve surrounding the outside of said ferrule.
References Cited in the file of this patent UNITED STATES PATENTS 1,835,000 Berthold Dec. 8, 1931 1,975,885 Wellman Oct. 9, 1934 2,297,336 White Sept. 29, 1942 2,318,648 Penfold May 11, 1943 2,478,082 Broske Aug. 2, 1949 2,499,297 Buchanan Feb. 28, 1950