US 2576528 A
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Patented Nov. 27, 1951 CONNECTOR WITH HARD PARTICLE LINING Irving Frederick Matthysse, New York, N. Y., as signor to Burndy Engineering Company, Inc., a
corporation of New York Application August 7, 1948, Serial No/3,923 3 Claims. (Cl. 17d-$4) My invention relates to connectors having tubular bodies that may be .used to splice wires or cables, and more particularly to the types that are indented to the wire and locked thereto by hard particles that key the connector to the wire.
Hitherto, in actual practice, such devices have employed chromium, Nichrome or non-metallic particles applied to the inside surface of the tubular connector, as is illustrated in Pat. No. M9209 issued February 28, 1939. These particles produce unsatisfactory results. where the connector is used to transmit current or where the metal of the particles is dierent from that oi the connector or wire, for in the first case chromium, Nichi-ome and hard non-metallic particles are highly resistant to the flow of current, and in the latter case electrolytic corrosion may set in.
Accordingly, the primary object of my invention is to provide a suitable keying-in material that may be secured to the inside oi' a hollow connector to forni a lining which; will more nearly approach the conductivity of the metal forming the connector body, than particles previously used for this purpose, and which additionally will not cause electrolytic corrosion.
i have iound that l can solve the problem of conductivity and electrolytic corrosion when copper connectors and wires are employed by alloying copper with a small amount of beryllium. Unfortunately the alloy when sprayed does not harden suflicientiy to warrant extensive use as a keying material. Since the aforesaid alloy may be made exceptionally hard, another object of my invention resides in providing a method of hardching the particles secured to the inside of tubular connectors.
Copper connectors of the splicing type are considerably worked during the manufacturing process, and indention ci the connector walls for securing the connector to a wire requires readily malleable material. This can be accomplished by heating and annealing the copper connector thereby softening the walls.
A still further object consists in providing a method whereby the connector body can be soitened and the alloy particles hardened. l
l have further discovered that by applying the molten alloy inside the connector walls, that l can thereafter harden the alloy and soiten the connector walls in one operation by simultaneously heating the connector with the alloy particle lining.
Other objects consist in providing methods oi applying the alloy particles to the connector in a manner which will be least expensive, and readily adaptable to mass production methods.
I accomplish these and other objects and obtain my new results as will be apparent from the device described in the following specification, particularly pointed out in the claims, and illustrated in the accompanying drawing in which:
Fig. l is a side elevation of a connector splice having an inner particle lining made in accordance with my invention.
Fig. 2 is an enlarged cross sectional view taken in the plane 2-2 of Fig. l.
Fig. 3 is a side elevation, partly in section of my connector splice secured to a conductor.
Fig. l is a cross-sectional view of the same taken in the plane l-l oi Fig. 3, showing the indenting dies in position.
Fig. '5 is an enlarged longitudinally sectioned and fragmentary view of the connector wall to which the particle lining has been secured with the conductor in position, and before indentation.
Fig. 6 is a similar view after indentation.
ln the drawings, reference numeral i0 designates a tubular body or sleeve having an internal hard particle lining li. The diameter of the internal bore oi the sleeve must be sufiicient for clearance over the wire i2, allowing for the thiol;- ness of the particle lining. The wire stops I3 and Ii may be formed in the bore to prevent inserting the wire too far, by indenting the sleeve as at I5. Each entrance I3, to the inside of the sleeve is well chamfered or rounded as at I1, to prevent nicking the wire and to prevent breakage due to possible vibration. The chamfer l'l-A on the outside is to prevent snaggng when the wire and sleeve are pulled over a cross-arm of a pole.
The compressed portions or indents I8, are produced by compressing dies I9 and 2li, shown in Fig. 4, which may leave a small flash 2l. As a result oi these indentations the surface of the wire takes on a wavy form as seen at Fig. 3, thereby increasing the grip of the sleeve on the wire.
In Figure 5, there is illustrated an enlargement of a portion of a longitudinal section or the sleeve with the wire inserted in place. The particles are preferably formed with sharp points, indicated hy the roughness of the liner .i l, on the sleeve it. Both the inside oi the sleeve 23, and the outside of the wire 2d, may he smooth. The hard particles forming the liner are secured to the inside wall by a number oi methods hereinafter explained. After compression this enlarged longitudinal section appears as in Figure 6, in which the individual hard particles 25, are seen to have impressed themselves into the softer surfaces of the sleeve and wire. each particle preferably acting as a key" to prevent any slipping of the wire relative to the sleeve under longitudinal tension. Thus with a suitable arrangement or indentatlons each having the proper amount of compression or depth, the wire will not slip under tension, and will fail only when the ultimate strength of the wire is approached and preferably outside the connection.
Particles made of copper containing from 1% to 23/4% of beryllium is satisfactory. I have found that 98% copper and 2% beryllium is preferred and that a aaxcess of 2% of beryllium does not materially add to the hardness of the alloy to justify the expense of the added quantity of beryllium and will lower the current carrying capacity of the alloy. The 2% alloy has a current carrying capacity, for equal temperatures, of approximately one-half that of pure copper and approximately equal to the current carrying capacity of materials customarily used to make electrical connectors. On the other hand', the 2% lberyllium-copper alloy has an electrical conductivity of over fifteen times that of Nichrome, now used as a particle lining.
The 2% beryllium-copper alloy has a Rockwell hardness of N72 compared with 15N40, the Rockwell hardness of hard drawn copper wire. Thus the alloy particles will penetrate copper wires and, of course, the much softer pure copper, without difficulty. Irregular and pointed particles suitable for a sleeve liner may be obtained from this material -by spraying the molten alloy with a conventional metal spraying gun and directing this spray into the barrel of the connector sleeve causing the particles to adhere when they strike the inner surface of the sleeve. Thereafter the particle lining is treated by a heat treating process which simultaneously increases the hardness of the lining while annealing the copper sleeve to the correct degree of malleabllity. A suitable temperature is approximately 650 F., held for about one hour, and cooled slowly thereaften Y Another method of applying the particles to the inside of a sleeve consists in coating thereon a thermosetting material such as a silicon resin or any suitable thermo-plastic adhesive. In such method the particles may be applied to the coated surface of the sleeve, and the combined sleeve,
ess for manufacturing particles of the proper size and shape, and hardening them while in their loose form. This can be accomplished by spraying the molten alloy into cold Water after which the particles maybe collected, 'and sorted size. The particles may then be hardened by the aforementioned heat-treatment,l and applied to the inner surface oi' the sleeve. This may be advantageous where it is desired to heat the sleeve to a different temperature than that needed tov harden the particles.
, It will be thus seen that by hardening the keying particles after they are formed, the process of making particles andA the materials for them need not be restricted to those processes and materials which produce hard particles.
I have thus described my invention, but I desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and, therefore, I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to attain these objects and accomplish these results.
l. A connector for joining wires or cables thereto which comprises a tubular metal body having a smooth inner wall surface, a particle lining securedto the inner wall, said particles being made of beryllium copper.
' 2. A connector for joining wires` or cables thereto which comprises a' tubular metal body having a smooth inner wall surface,y a particle lining secured to the inner wall, said particles being made of metal having a Rockwell hardness `of approximately 15N72.
3. A connector for joining wires or cables thereto which comprises a tubular metal body having a smooth inner wall surface, a particle lining secured to the inner wall, said particles being made of beryllium copper having a Rockwell hardness of approximately 15N72.
IRVING FREDERICK MATTHYSSE.
REFERENCES crrmnV The following references are of record in the file of this patent: y
UNITED STATES PATENTS Mudge Dec; 4, 1945