US 3851298 A
A length of soft copper sleeving is slipped over a stranded wire and the combination is then wrapped about a wrapping post in the conventional manner for solderless wrapped connections.
Description (OCR text may contain errors)
United States Patent Sokolov Nov. 26, 1974 [5 WRAPPED WIRE CONNECTION 2,671,889 3/1954 Vickery 339/276 R 3,309,647 3 1967 V H II 339 276 R [751 Inventori amid 50km, Moorestown, 3,431,547 3/1969 L2 l l :5l'. 339/272 A  Assigneel RCA Corporation, New York7 3,605,079 9/1971 Sehncider 339/276 R  Flled: Apr 1973 Primary Examiner-Joseph H. McGlynn [21 Appl. No.: 348,763 Attorney, Agent, or Firm-Edward J. Norton; William Squire 52] U.S. (,l. 339/276 A, l74/94 R |5l 1 Int. Cl H0lr 5/08 57 ABSTRACT 8] Field of Search 339/223, 276, 278;
174/74 R, 75 R, 94 R A length of soft copper sleevmg 1s slipped over a stranded wire and the combination is then wrapped  References Cited about a wrapping post in the conventional manner for UNITED STATES PATENTS solderless wrapped connections.
535,592 3/1895 Lillie 174/94 R 3 Claims, 6 Drawing Figures WRAPPED WIRE CONNECTION BACKGROUND OF THE INVENTION The present invention relates to a solderless connection in which a wire conductor is wrapped around a terminal post.
In conventional solderless wrapped connections a solid wire conductor is wrapped about a terminal post to form a gas-tight electrical connection between the wire conductor and the post. In these connections a specified number of turns of wire, under tension, are wrapped around a post'having sharp corners. The sharp corners of the post produce high pressure points resulting in indentations in the wire or in both the wire and the post. The resulting high pressure points are gastight and provide electrical continuity between the wire and the post.
However, such wire wrapped connections are made with solid wires. Stranded wires'need to be connected by other techniques including soldering or the use of crimp-type solderless terminals. These other techniques are bulkier, less reliable, and more costly than the wrapped connections and therefore, are less suitable for high density, high reliability applications. In certain instances, it has been found necessary to use stranded wires in complex electronic equipment and still require high reliability and high density terminations. In these instances, due to the presence of stranded wires, solderless wrapped connections have not been possible.
SUMMARY OF THE INVENTION IN THE DRAWINGS FIG. 1a is .a partial sectional view through the longitudin al axis of a stranded wire surrounded with a conductive annular member,
FIG. 1b is a perspective view of the conductive annular member of FIG. 1a,
'FIG. 2a is a sectional view of an alternate embodiment of the invention utilizing an annular member surrounding a portion of the insulation on a wire,
FIG. 2b is a perspective view of the annular member of FIG. 2a,
FIG. 2c is a sectional view of the embodiment of FIG. 2a after the annular member is crimped to the insulation on the stranded wire, and
FIG. 3 is an elevational view of a wrapped solderless connection utilizing the embodiment of FIG. la.
DETAILED DESCRIPTION In general, a stranded wire includes a conductive stranded wire core 12 and an insulating jacket 14. A portion of core 12 is bared by conventional techniques for length suitable for wrapping about a conventional wrapping post in a manner illustrated in FIG. 3. Wire wrapping connections are well known and description thereof will not be provided herein. A description of industry accepted standards for making such connections is given in a United States government publication entitled Military Standard 1,130," dated Nov. 12, 1965.
In accordance with the present invention the bared portion of core 12 is inserted into a fully annealed, seamless copper sleeve 16 having a length of about the same size as the bared portion. The sleeve inner diameter closely receives core 12 preferably leaving a few mils clearance therebetween..The sleeve and core combination may then be wrapped about a wrapping post by the well known wrapping techniques. Sleeve 16 is fully annealed copper thus allowing deformation without failure thereof when wrapped about the wrapping post.
In one embodiment using 30 guage stranded wire, sleeve 16 comprises a copper tube of 0.025 inches outside diameter and 0.020 inches inside diameter. The stranded wire has an outer diameter of 0.0124 inches leaving a 0.0076 inch clearance therebetween. This assembly is then wrapped to a post 0.025 inches square.
As shown in FIG. 3, the combined core 12 and sleeve 16 are wrapped around wrapping post 20. Post edges such as edges 22 and 24 compressively deform sleeve 16 to form the gas-tight wire wrap joint known in the solderless wire wrapping art. The ductile characteristics of sleeve 16 and wall thickness thereof are selected such that, when deformed during the wire wrap connection to post 20, no cracks or stress failures are induced in sleeve 16. Such ductile characteristics are well defined in the metallurgical art and the selection of a sleeve wall thickness and sleeve ductility thereof for a particular stranded wire diameter are within the knowledge of those skilled in the art. Core 12 serves as a support for sleeve 16 during the deformation of tubing 16, permitting sleeve 16 to swaged to core 12 when wrapped about post 20, forming the electrical connection between the core 12, sleeve 16 and post 20. Deformation of sleeve 16 in forming the swaged connection with core 12 prevents longitudinal slippage of sleeve P6 with respect to core 12.
An alternate preferred embodiment of the present invention is illustrated in FIGS. 2a through 2c wherein a typical stranded wire 10' includes a stranded core 12' surrounded partially by an insulating jacket 14". An annular sleeve 30 is enlarged at end 32 which slips over a portion of jacket 14'. Portion 34 closely receives bared stranded core 12' in a manner described above with respect to the embodiment of FIG. la.
Sleeve 30 is formed of fully annealed copper by conventional metal working techniques. Enlarged portion 32 is then crimped to jacket 14' into the configuration illustrated in FIG. 2c. This advantageously permits locking of sleeve 30 to the stranded wire and jacket assembly duringthe manufacturing assembly operations prior to the actual wrapping step. Additionally, the arrangement of FIG. 2c increases the strength of the wrapped connection due to the connection of sleeve 30 with insulation 14'. The length of portion 34 is made sufficiently long to provide sufficient wrapping about a a length of stranded wire,
a conductive annular member surrounding said length, and
a wire wrapping post wrapped with said surrounded length of wire forming an electrical connection therewith.
- 2. An electrical connection comprising;
a wrapping post,
a length of stranded wire,
a length of electrically conductive annealed tubing disposed on said length of stranded wire, said stranded wire and said tubingv being disposed wrapped about said post and forming with said post a solderless electrical connection.
3. The connection of claim 2 wherein said length of stranded wire includes a portion thereofsurrounded by an electrical insulating cover, said length of tubing including an enlarged portion disposed at one end thereof, said one end being disposed on said insulating cover and crimped thereto.