US3663741A

US3663741A - Terminal and wrapped wire assembly

Info

Publication number: US3663741A
Application number: US134808A
Authority: US
Inventors: Robert Holbrook Cushman
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1971-04-16
Filing date: 1971-04-16
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16

Abstract

A number of wires are wrapped about a terminal. An insulationfree section of a first wire is initially wrapped about the terminal with a relatively low number of turns, e.g., two, leaving a short end portion which is directed axially along the terminal. The end portion of the first wire is then bonded to the terminal, the bonding operation compacting the end portion. Next, an insulation-free section of a second wire is wrapped about the terminal with a relatively low number of turns, e.g., two, overlapping the bonded and compacted end portion of the first wire, leaving a short end portion which is directed axially along the terminal. The end portion of the second wire is then bonded to the terminal, the bonding operation compacting the end portion. Additional wires may next be added successively in like, overlapping manner. A strong, compact terminal and wrapped wire assembly is formed by this method.

Description

United States Patent Cushman 51 May 16,1972

[54] TERMINAL AND WRAPPED WIRE ASSEMBLY Robert Holbrook Cushman, Lower Moreland Township, Montgomery County, Pa.

[ 72] Inventor:

[73] Assignee: Western Electric Company Incorporated,

New York, NY.

[22] Filed: Apr. 16, 1971 [21] Appl. No.: 134,808

3,088,087 4/1963 Colten ..339/276 A X Primary ExaminerDarrell L. Clay Attorney-W. M. Kain, R. P. Miller and R. C. Winter 57 ABSTRACT a A number of wires are wrapped about a terminal. An insulation-free section of a first wire is initially wrapped about the terminal with a relatively low number of turns, e. g., two, leaving a short end portion which is directed axially along the terminal. The end portion of the first wire is then bonded to the terminal, the bonding operation compacting the end portion. Next, an insulation-free section of a second wire is wrapped about the terminal with a relatively low number of turns, e.g., two, overlapping the bonded and compacted end portion of the first wire, leaving a short end portion which is directed axially along the terminal. The end portion of the second wire is then bonded to the terminal, the bonding operation compacting the end portion. Additional wires may next be added successively in like, overlapping manner. A strong, compact terminal and wrapped wire assembly is formed by this method.

10 Claims, 3 Drawing Figures Patented May 16, 1972 N m g T% PM wu q w s 5 W w Q Background of the Invention This invention relates to a terminal and wrapped wire assembly and, more particularly, to a terminal and wrapped wire assembly in the form of a terminal about which a number of wires are compactly wrapped.

In the art of joining wires to a terminal or other elongated member, it is known to wrap one or more wires about the terminal. The terminal to be wrapped is normally of multi-cornered cross section in order to effect a firm anchoring of each wrapped wire. Lengths of wire are selected so as to provide several side-by-side turns of each wrapped wire. A conventional wire wrapping tool wraps the entire selected length of each wire about the terminal. Typically, wire lengths are selected such that at least four or five turns may be wrapped, in order to secure the wire. firmly about the multi-cornered terminal. This number of turns, while affording sufficient strength and durability to each wire-to-terminal interconnection, requires the use of a fairly long axial portion of the terminal for each wrapped wire. The number of wires which may be joined to any given axial length of terminal is, thus, severely limited.

It is also known to bond to an elongated member a wire or strand which has been wrapped about the member. Typically, the wire is bonded to the member at the wrapped section of the wire. This furnishes a more rigid and secure assembly than that which is present when only the wire wrapping operation is employed. However, it has been found that the wrapped and bonded structure, as described, incorporates undesirably high stress concentrations in the area of the wrapped and bonded wire, making it desirable to provide some manner of strain relief to the assembly.

SUMMARY OF THE INVENTION An object of the invention resides in new and improved terminal and wrapped wire assemblies.

The invention contemplates the wrapping of a relatively short section of a first wire about a first axial portion of a terminal, the wrapping typically utilizing about two turns of wire. Another section, such as a short end section, of the first wire is directed axially of the terminal along a second axial portion of the terminal, preferably immediately adjacent to the first axial portion of the terminal. The end section of the first wire is then affixed or bonded to the second axial portion of the terminal, a preferred manner of affixation involving applying sufficient bonding pressure and heat to the end section to compact and bond the end section to the terminal. A significant degree of strain relief is provided to the wrapped section of the first wire by virtue of the fact that bonding occurs only at the end section of the wire and not at the wrapped section. The affixation of only the wire end section to the terminal also permits the wrapping of the wire about a terminal of circular or other comer-free cross section, since the wire-to-terminal bond at the wire end section will obviate any need for an anchoring effect to occur along various corner surfaces of the terminal.

A relatively short section of a second wire is next wrapped overlying the bonded and compacted end section of the first wire immediately adjacent to the wrapped section of the first wire. The wrapped section of the second wire acts to secure and protect the bonded and compacted end section of the first wire. Once again, only approximately two turns of wire are required for the wrapping of the second wire about the second axial portion of the terminal and over the end section of the first wire. An additional section, such as a short end section, of the second wire is directed along a third axial portion of the terminal. The end section of the second wire is then affixed or bonded to the third axial portion of the terminal, the bonding pressure and heat once again preferably compacting the bonded end section. Additional wires may thereafter be wrapped and bonded in like manner. A wrapped wire and terminal assembly will result, wherein a relatively high density of securely and durably attached wires results.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1-3 of the drawing are isometric views illustrating three successive stages in the formation of a terminal and wrapped wire assembly in accordance with the invention.

DETAILED DESCRIPTION Referring initially to FIG. 1, an electrically conductive wire 11 may be covered with a layer of insulation 12. All insulation covering has been stripped, however, or is otherwise absent from a length of the wire 11 which is to be joined to a terminal 13. A number of other wires are also to be joined to the terminal 13, as depicted in FIGS. 2 and 3. The terminal 13 is an elongated, electrically conductive member which may have a cross-sectional shape, e.g., square, furnishing a number of corners about which each wire may anchor upon a wrapping of the wire around the terminal. Alternatively, the terminal may be of circular or other comer-free cross section.

In order to join the wire 11 to the terminal 13, a short section of the insulation-free length of the wire is first wrapped about an axially extending portion of the terminal, for example, through the use of a conventional wire wrapping tool (not shown). The section of the wire wrapped about the terminal 13 is spaced from an end section 14 of the wire 11. The number of turns of wire which are wrapped about the terminal is relatively small, typically from one to three turns and preferably approximately two full turns of wire.

The end section 14 of the wire 11 constitutes a short tail segment which is directed axially of the terminal 13 along an axial portion of the terminal immediately adjacent to the axial portion of the terminal about which the short section of the wire has been wrapped. In order to secure further the wire 11 to the terminal 13, the end section 14 of the wire is now attached to the terminal by a bonding operation. The bonding of the end section 14 to the terminal 13 also permits a relatively loose wrapping of the wire 11 about the terminal, lessening stresses in the wrapped section of the wire. Bonding preferably acts to flatten or compact the end section 14, as shown at 16, while affixing the end section to the terminal. Mechanical thermal pulse bonding, as described in application Ser. No. 701,185, filed by applicant on Jan. 29, 1968 and now abandoned, conventional thermocompression bonding, or any other suitable bonding or affixing operation may be employed.

A second wire 17 (FIG. 2) is next joined to the terminal 13 in similar manner to the joining of the first wire 11. A short insulation-free section of the wire 17, spaced from an end section 18 of the wire, is wrapped about the terminal. The short section of the second wire 17 is wrapped so as to overlap the bonded and compacted end section 14 of the first wire 11 and occupy the axial portion of the terminal 13 immediately adjacent to that occupied by the short wrapped section of the first wire. Both axial and radial structural compactness is provided by the flattening of the end section 14 of the first wire 1 l and then the wrapping of the second wire 17 over the flattened end section and immediately adjacent to the short wrapped section of the first wire. Once again, relatively few turns of wire, preferably two turns, are utilized to form the short wrapped section of the second wire 17.

The end section 18 of the second wire 17 constitutes a short tail segment which is directed axially of the terminal 13 along an axial portion of the terminal immediately adjacent to that about which the short section of the second wire has been wrapped. In similar manner to the afiixing of the end section 14 of the first wire 11 to the terminal 13, the end section 18 of the second wire 17 is affixed to the terminal, for example, by bonding with sufficient pressure and heat to flatten or compact the end section at a bonding location 19.

In like fashion, a third wire 21 (FIG. 3) may next be joined to the terminal 13 by wrapping a short section of the third wire overlying the end section 18 of the second wire 17 and then affixing an end section 22 of the third wire to the terminal by compression bonding. Any number of additional wires may be added in like manner, as illustrated in FIG. 3 by a wire 23 (wire n) wrapped overlying a preceding wire 24 (wire n-l) and having a short end section 26 bonded at 27 to the terminal 13. A strong, compact terminal and wrapped wire assembly results, wherein a high density of wrapped wires is provided on the terminal, wherein each overlapping wrapped wire section aids in securing and protecting a bonded and compacted end section of an adjacent wire, wherein the bonding of each wire end section allows some degree of strain relief in the wrapped section of the wire by permitting a relatively loose wrapping operation, and wherein a terminal of circular or other comerfree cross section may be utilized by virtue of the bonding of the wire end sections to the terminal.

The degree of compactness of the wrapped terminal assembly may be noted by viewing FIGS. 2 and 3. It should be clear that, although each

wire

11, 17, 21, 23, is wrapped with two turns about the terminal 13, the structure is such that only one turn separates the positions at which adjacent pairs of wires come into contact with the terminal. This makes it possible to increase the packaging density to the point at which the space taken up by each wire connection approximately equals the diameter of an insulated wire.

A special purpose tool, not forming a part of the invention, may be employed, upon a squeeze of a handle of the tool, to wrap each wire about the terminal, clamp the end section of the wrapped wire against the terminal running axially of the terminal, bond the clamped wire end section to the terminal, and then release the wire, preparatory to performing a similar operation on a succeeding wire.

It is to be understood that the described assembly is simply illustrative of one embodiment of the invention. In other embodiments overlapping wire wrap sections may be spaced one from another and/or may overlap non-bonded sections of one or more wires, which overlap ed wires may be affixed or bonded elsewhere to the terminal or may remain unbonded throughout their entire lengths. Additionally, one or more wire end sections may be secured to the terminal prior to the wrapping of adjacent sections of the secured wires about the terminal. Many additional modifications may be made in accordance with the principles of the invention.

What is claimed is:

l. A terminal and wrapped wire assembly, comprising:

a tenninal; and

a plurality of wires each having a wrap section and a second section, the second section of each wire extending axially along the terminal and the wrap section of each wire but one being wrapped about the terminal and over a second section of another of said wires.

2. In the assembly of claim 1:

each wire being affixed to the terminal at a position displaced axially from the wrap section of the wire.

3. In the assembly of claim 1:

each wire wrap section comprising substantially two turns of wire.

4. In the assembly of claim 1:

each wire wrap section being positioned immediately adjacent to a wrap section of at least one other of said wires.

5. In the assembly of claim 1:

each wire wrap section being positioned immediately adjacent to a wrap section of at least one other of said wires and each wire but one being affixed to the terminal beneath a second section of an adjacent one of said wires.

6. A terminal and wrapped wire assembly, comprising:

a terminal; and

a plurality of wires each having an end section and a wrap section spaced from the end section, the end section of each wire extending axially along a different axial portion of the terminal and the wrap section of each wire being wrapped about an adjacent axial portion of the terminal with each wrap section but one overlying the end section of an adjacent one of said wires.

7. In the assembly of claim 6:

each wire wrap section comprising substantially two turns of wire wrapped about the terminal and each underlying wire end section.

8. In the assembly of claim 6: each wire end section being affixed to its respective axial portion of the terminal.

9. A terminal and wrapped wire assembly, comprising:

a terminal; and

a plurality of wires each having an end section and a wrap section spaced from the end section, the end section of each wire being bonded to a different axial portion of the terminal and the wrap section of each wire being wrapped about an adjacent axial portion of the terminal with each wrap section but one overlying the end section of an adjacent one of said wires.

10. in the assembly of claim 9:

Claims

1. A terminal and wrapped wire assembly, comprising: a terminal; and a plurality of wires each having a wrap section and a second section, the second section of each wire extending axially along the terminal and the wrap section of each wire but one being wrapped about the terminal and over a second section of another of said wires.

2. In the assembly of claim 1: each wire being affixed to the terminal at a position displaced axially from the wrap section of the wire.

3. In the assembly of claim 1: each wire wrap section comprising substantially two turns of wire.

4. In the assembly of claim 1: each wire wrap section being positioned immediately adjacent to a wrap section of at least one other of said wires.

5. In the assembly of claim 1: each wire wrap section being positioned immediately adjacent to a wrap section of at least one other of said wires and each wire but one being affixed to the terminal beneath a second section of an adjacent one of said wires.

6. A terminal and wrapped wire assembly, comprising: a terminal; and a plurality of wires each having an end section and a wrap section spaced from the end section, the end section of each wire extending axially along a different axial portion of the terminal and the wrap section of each wire being wrapped about an adjacent axial portion of the terminal with each wrap section but one overlying the end section of an adjacent one of said wires.

7. In the assembly of claim 6: each wire wrap section comprising substantially two turns of wire wrapped about the terminal and each underlying wire end section.

9. A terminal and wrapped wire assembly, comprising: a terminal; and a plurality of wires each having an end section and a wrap section spaced from the end section, the end section of each wire being bonded to a different axial portion of the terminal and the wrap section of each wire being wrapped about an adjacent axial portion of the terminal with each wrap section but one overlying the end section of an adjacent one of said wires.

10. In the assembly of claim 9: each wire wrap section comprising substantially two turns of wire wrapped about the terminal and each underlying wire end section.