US3371412A

US3371412A - Method of terminating a resistor

Info

Publication number: US3371412A
Application number: US526898A
Authority: US
Inventors: James R O'keeffe
Original assignee: Dale Electronics Inc
Current assignee: Dale Electronics Inc
Priority date: 1966-02-11
Filing date: 1966-02-11
Publication date: 1968-03-05
Anticipated expiration: 1985-03-05

Description

March 5, 1968 J, R. O'KEEFFE 3,371,412

METHOD OF TERMINATING A RESISTOR Filed Feb. 11, 196e INVENTOR. f4/#E5 E @Jeff/FFE BY @MWC/@ffm 3,371,412 METHOD F TERMHNATING A RESISTOR James R. GKcelie, Columbus, Nebr., assignor to Dale Electronics, Inc., Columbus, Nebr., a corporation of Nebraska Filed' Feb. 11, 1966, Ser. No. 526,898 8 Claims. (Cl. 29-621) This invention relates to a resistor and more particularly to a resistor of the continuous wound type and the method of making the same. This invention also relates to resistors wherein the resistance means is comprised of deposited carbon, metal film or the like.

Resistors of the type disclosed herein consist generally of a core overwound with resistance wire and terminals electrically connected to the resistance wire at opposite ends of the core. The problem that the resistor industry is facing is to develop a satisfactory method of terminating the continuous wound resistors which provides good mechanical strength and electrical contact between the terminals and the resistance wire and which does not allow the resistance wire to shift on the core or to protrude from the end of the resistor. Several different methods of termination have been attempted but all have proved to be expensive and unreliable to various degrees. One method used heretofore was to weld the lead wire to the terminal. A second method used heretofore was to insert the lead wire through slits formed in the terminal. A third method used heretofore was to pinch the lead wire between the ends of the terminal stock. These three methods require that the fiber glass or the like core overwound with resistance wire be cut to length prior to the attachment of the terminal. When so cut, the core and resistance Wire unravel thereby causing shorted turns, poor electrical contact, poor mechanical strength, and resistance wire protruding from the terminals. Certain of the manufacturers of resistors have attempted to solve the unraveling problem by several methods including core impregnants, insulated wire, etc. These remedial methods have also been generally unsuccessful due to their expense and unreliability.

Therefore, it is a principal object of this invention to provide a resistor wherein the core and the resistance wire do not become unravelled during the manufacture thereof.

A further object of this invention is to provide a resistor having a ber glass core and resistance wire overwound thereon which does not become unravelled during the manufacture thereof.

A further object of this invention is to provide a resistor wherein the resistance wire does not objectionably protrude from the resistor.

A further object of this invention is to provide a resistor which has good electrical contact between the resistance wire and the terminals.

A further object of this invention is to provide a resistor which has good electrical contact between the terinals and the lead wires.

A further object of this invention is to provide a resistor which has excellent mechanical strength.

A further object of this invention is to provide a method of making a resistor wherein the terminals are attached i thereto before the core is cut to length.

A further object of this invention is to provide a machine process method of making a resistor which does not require core impregnation or other similar methods of adhering the resistance wire to the core.

A further object of this invention is to provide a method of making a resistor which provides two terminations per machine cycle.

A further object of this invention is to provide a method nited States Patent of making a resistor which eliminates a secondary operation to 'bond the lead wire to the terminal.

A further object of this invention is to provide a resistor which is economical of manufacture, durable in use and refined in appearance.

These and other object will be apparent to those skilled in the art.

This invention consists in the construction, arrangements, and combination of the various parts ofthe device, whereby the objects contemplated arev attained as hereinafter more fully set forth, specically pointed out in the claims, and illustrated in the accompanying drawings in which:

FIG. l is a side view of the resistor with a portion thereof cut away to more illustrate the invention;

FIG. 2 is end view of the resistor of FIG. 1;

FIG. 3 illustrates one of the initial steps in the method of making the resistor wherein the wound core and lead wire are fed into the machine in parallel paths and the terminal stock is fed perpendicularly to the lead wire;

FIG. 4 illustrates the components of the resistor after the terminal stock has been cut and crimped around the lead wire and core;

FIG. 5 illustrates the components of the resistor after the assembly has been cut through the middle of the terminal to form two assemblies;

FIG. 6 illustrates the ends of the two assemblies formed illustrating the manner in which the lead wire has been bent back over the terminal;

FIG. 7 illustrates one of the initial steps in a modified method of making the resistance wire wherein the lead wire has vbeen wrapped around the core; and

FIG. 8 illustrates the components of the resistor of FIG. 7 after the assembly has been cut through the middle of the wrapped lead wire and through the core to form two assemblies.

FIG. 9 is a sectional view of a bimetallic terminal stock material which may be substituted for the terminal stock material of FIGS. 1-6.

The resistor of FIG. l is referred to by the reference numeral 10 while the resistor of FIG. 8 is generally referred to by the reference numeral 11.

Resistor 1li is constructed by feeding an elongated core material 12 of fiber glass or the like having a resistance wire 14 overwound thereon into a machine 16. As seen in FIG. 3, machine 16 includes spaced apart members 18 and 2t). An elongated lead wire material 22 of copper or the like is fed into machine 16 parallel to core material 12 and is spaced therefrom and an elongated strip of terminal stock 24 is fed into machine 16 transversely to core material 12 and lead wire material 22. Core material 12, lead wire material 22 and terminal stock 24 are fed into machine 16 simultaneously and the relationship between these components at this time is illustrated in FIG. 3. Terminal stock 24 may be comprised of a bimetallic terminal stock material 40 such as seen in FIG. 9 if desired. Terminal stock 40 is provided with a brazeable layer 42 comprised of silver solder or the like laminated onto a brass or like layer 44.

The next step in the manufacture of resistor 10 is illustrated in FIG. 4. The terminal stock 24 is cut to the proper length and crimped around the lead wire material 22 and core material 12 -by any suitable means. The crimping of terminal stock 24 around lead wire material 22 and core material 12 causes lead wire material 22 and terminal stock 24 to be moved towards core material 12 at a point between

members

18 and 20 of machine 16 thereby causing lead wire material 22 to -be bent as illustrated in FIG. 4. If terminal stock 49 is used rather than terminal stock 24, the terminal stock would be heated in a secondary operation thereby fusing or brazing layer 42 into intimate contact with the resistance wire.

The next step in the manufacture of resistor 10 is illustrated in FIG. 5. The assembly is cut through the middle of terminal stock 24 transversely to the longitudinal axis of core material 12 |by any convenient means thereby forming opposite ends of two resistors 10. Machine 16 would normally be adapted so that the other ends of the two resistors 10 would be terminated simultaneously with the termination of the ends shown and described. FIG. 6 illustrtaes the manner in which the lead wire material 22 is bent back over the terminals of the two resistors 10.

The completed resistor 10 is shown in FIG. 1 and includes a core 12A overwound with resistance wire 14A. A terminal 24A is provided at one end of resistor 10 and a terminal 24B is provided at the other end of resistor 10. A lead wire 22A is operatively electrically connected to terminal 24A as previously described and includes a U-shaped end portion 26A embracing the interior surface, the inner end and exterior surface of terminal 24A. Lead wire 22A also includes an L-shaped portion 28A which at rst extends downwardly and thence outwardly with respect to end portion 26A and terminal 24A as seen in FIG. l.

Terminal 24B is identical to terminal 24A and for that reason will not be described in detail. A lead wire 22B, identical to lead Wire 22A, is electrically connected to terminal 24B as previously described. Resistor 10 may be coated with any suitable material if desired.

With respect to FIGS. 7 and S, the numeral 30 generally designates a core material overwound with resistance wire 32. A lead wire material 34 is simply wrapped around core 30 as illustrated in FIG. 7. The assembly is then cut through the middle of the wrapped lead wire material (FIG. 8) by any suitable means. The cutting of the assembly results in the opposite ends of two resistors 11 being formed wherein the wrapped lead Wire material serves as both a lead wire and a terminal. Normally, the termination of the opposite ends of the two resistors 11 would be accomplished at the same time as the termination of the ends shown in FIG. 8. In FIG. 8, the terminal assembly at the right end of the left resistor 11 is referred to as 34A and the terminal assembly at the left end of the right resistor 11 is referred to as 34B.

The advantages of the resistor 10 are as follows: 1) the invention allows machine processes which do not require'core im-pregnation or some other method o'f adhering the resistance wire to the core; (2) a double Width terminal stock is used which is sliced in two thereby giving two terminations per machine cycle; (3) the slicing operation occurs after termination thus eliminating frayed ends or resistance wire protruding from'the terminals; (4) mechanical strength of the resistor is increased because stress imposed on the lead wire acts against the bend thereof and not on the joint; the resistor is economically manufactured since a secondary operation is not required to Abond the terminal to the lead wire; and (6) mechanical strength and electrical contact are further improved byuse of a fusible or`brazeable terminal stock (example: silver solder laminated to brass), which when heated in a secondary operation provides intimate contact with the resistance wire.

The advantages of the resistorll are as follows: (l) the Wrapped lead wire serves as both a terminal and a lead wire; and (2) superior mechanical strength and electrical contact are realized, and further improved by use of fusable lead wire which when heated in a secondary operation provides intimate contact with the resistance wire. While the resistor has been described as including a resistance wire overwound on a core, a resistor without a resistance wire can beproduced by the method described herein. Such resistors would substitute deposited carbon or, a metal iilm or the like for the resistance wire.

It should be noted that the resistor core can be of -any configuration and has been shown to be cylindrical in the drawings for sake of simplicity.

Thus it can be seen that the device and he method of making the same accomplishes at least all of the stated objectives.

Some changes may be made in the construction and arrangement of my method of terminating a resistor without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modiiied forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim: 1. The method of making a resistor, comprising the following steps:

securing a terminal stock material around an elongated core and a length of lead wire material, said core and lead wire being parallel, said core having resistance wire means operatively overwound thereon, said lead wire being positioned between the resistance Wire and the terminal stock material,

cutting said terminal stock material, said lead wire and said core at the approximate center width of said terminal stock material transversely to the longitudinal axis of said core thereby foaming one end of two resistors.

2. The method of claim 1 wherein the other end of one of the resistors is formed by securing a second terminal stock material around said one resistor core and around a second length of lead wire material, said core and said second length of lead Wire material being parallel, said second lead wire being positioned between the resistance wire and said second terminal stock material, and cutting said second terminal stock material, said second lead wire and said core at the approximate center width of said second terminal stock material transversely to the longitudinal axis of said core.

3. A method of terminating resistors comprising the steps of: providing a length of core material with resistance material thereon, providing a length of lead wire, providing a terminal band, securing said lead wire to said resistance material by wra-pping said terminal band around said core, said lead wire being between said band and said resistance material and having lengths thereof extending from both sides of said terminal band; severing said terminal band, said lead wire and said core in a direction substantially transverse to the longitudinal axis of said core.

4. The method of claim 3 wherein said securing includes the step of fusing said lead wire, terminal band and resistance material with a fusible material.

5. The method of claim 3 wherein said severing is ap- `proximately in'the center of said terminal band.

6. A method of terminating resistor comprising the steps of: providing a length of core material with resistance material thereon, providing a length of lead wire, securing said lead wire to said resistance material by wrapping a plurality of turns circumferentially around said core leaving a length of said lead wire at both ends of the wrapped section; severing said lead wire and said core through the wrapped portion of said lead wire.

7. The method of claim 6 wherein said securing includes the step of fusing said wrapped portion of said lead wire to said resistance material with a fusible material.

8. The method of claim 6 wherein said severing is approximately at the Icenter of said wrapped portion.

References Cited UNITED STATES PATENTS 1,745,939 2/1930 Loewe 338-308 X 2,113,674 4/1938 Brickman et al. 29-621 2,357,473 9/1944 Iira 338-308 X 2,402,122 6/1946 'Bollinger 338-322 X 2,489,409 11/1949 Green et al. 338-322 X 2,645,701 7/1953 Kerridge et al. 338-308 X 2,966,649 12/1960 Haynman 338-322 JOHN F. CAMPBELL, Primary Examiner.

'1. L.`CLINE, Assistant Examiner.

Claims

3. A METHOD OF TERMINATING RESISTORS COMPRISING THE STEPS OF: PROVIDING A LENGTH OF CORE MATERIAL WITH RESISTANCE MATERIAL THEREON, PROVIDING A LENGTH OF LEAD WIRE, PROVIDING A TERMINAL BAND, SECURING SAID LEAD WIRE TO SAID RESISTANCE MATERIAL BY WRAPPING SAID TERMINAL BAND AROUND SAID CORE, SAID LEAD WIRE BEING BETWEEN SAID BAND AND SAID RESISTANCE MATERIAL AND HAVING LENGTHS THEREOF EXTENDING FROM BOTH SIDES OF SAID TERMINAL BAND; SEVERING SAID TERMINAL BAND, SAID LEAD WIRE AND SAID CORE IN A DIRECTION SUBSTANTIALLY TRANSVERSE TO THE LONGITUDINAL AXIS OF SAID CORE.
6. A METHOD OF TERMINATING RESISTOR COMPRISING THE STEPS OF : PROVIDING A LENGTH OF CORE MATERIAL WITH RESISTANCE MATERIAL THEREON, PROVIDING A LENGTH OF LEAD WIRE, SECURING SAID LEAD WIRE TO SAID RESISTANCE MATERIAL BY WRAPPING A PLURALITY OF TURNS CIRCUMFERENTIALLY AROUND SAID CORE LEAVING A LENGTH OF SAID LEAD WIRE AT BOTH ENDS OF THE WRAPPER SECTION; SEVERING SAID LEAD WIRE AND SAID CORE THROUGH THE WRAPPED PORTION OF SAID LEAS WIRE.