US3229238A

US3229238A - Welded terminal resistor

Info

Publication number: US3229238A
Application number: US11745A
Authority: US
Inventors: Fredrick I Ellin
Original assignee: Consolidated Electronics Industries Corp
Current assignee: Consolidated Electronics Industries Corp
Priority date: 1950-02-02
Filing date: 1960-02-29
Publication date: 1966-01-11
Anticipated expiration: 1983-01-11

Description

' Jan. 11,1966 F. l. ELLlN 3,229,238

WELDED TERMINAL RESISTOR Original Filed Feb. 2. 1950 resistors of the foregoing type. the'resistors to glaze the enamel, the terminal lugs are incidentally oxidized, and sometimes burned. Accordingly, the terminallugs must be cleaned and tinned before installed. "siderable skill and precision to avoid damaging the glazed United States Patent 3,229,238 WELDED TERMINAL RESISTOR Fredrick I. Elihu, Skokie, Ill assignor, by mesne assignments, to Consolidated Electronics Industries Corp., New York, N.Y., a corporation of Delaware Division of application Ser. No. 142,070, Feb. 2, 1950,

now Platent No. 2,675,453, dated Apr. 13, 1954. Continllat on of abandoned application Ser. No. 403,484, Jan. 12, 1954. This application Feb. 29, 1960, Ser. No. 11,745

8 Claims. '(Cl. 338329) This invention is concerned generally with resistors and likeelectrical elements, and more particularly with an improved wire-wound resistor as an article of manufacture. This application comprises a division of my application Apparatus for Manufacture ofWelded Termiwinding resistance wire on a ceramic core. The ends of the wire are welded or otherwise electrically and mechanically secured to metallic bands encircling the core near the ends thereof. Each band conventionally comprises a strip of sheet metal bent around the core with the ends extending radially outwardly in the same direction from the core-arid'welded or otherwise secured together to form aterminal log for mounting the resistor and for making electrical connections thereto. The wiregenerally is bare, and atbest may be protected by a rather delicate coating of insulation. As a result, the wire is readily susceptible to physical damage and short circuits. To guard against this, the wire, core, and the bands exclusive of the outermost projecting ends thereof are genjerallycoated' with a vitreous enamel. The resistor is then fired to glaze the enamel.

Certain difficulties are encountered in manufacturing In the process of firing lead 'wires can be soldered to them when the resistor is Cleaning of the terminal lugs requires convitreous coating. Furthermore, conventional means or methods of cleaning metal surfaces, insofar as they can 'be applied to electrical resistors and the like, tend to leave areas which are not quite clean, or which are susceptible to'corrosion. This leads to imperfect bonding and eventually to poor electrical contact.

Toxprevent cracking of the core or the glazed vitrified coating, and to prevent loosening of the terminal bands,

Ice

as terminals. It is apparent that different sizes of resistors require different lengths of hands. When the lugs are integral with the bands in accordance with conventional practice, a large number of sizes of integral bands and lugs must be kept on hand. This number is further increased when it is considered that many different types and shapes of mounting lugs are required for different installations.

It is an object of this invention to obviate all of the above enumerated faults and others by providing a resistor with terminal bands having only short integral projections extending therefrom and a terminal lug or tab welded to each projection. v

More specifically, it is an object of this invention to provide a resistor having a terminal band wherein a terminal lug or tab is butt welded to a short integral projection of the band.

A further object of this invention is to provide a resister or the like having a coating stabilized by heat wherein projecting conducting members are instantly oxidized during stabilization of such coating by the application of heat wherein the projections are clipped off to provide clean surfaces and electrical terminals are welded onto the clipped, clean surfaces.

Other and further objects and advantages will be apparent from the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a resistor constructed in accordance with the principles of this invention prior to the welding of the terminal lugs thereon, the vitreous enamel coating being omitted for clarity of illustration;

FIG. 2 is a viewsimilar to FIG. 1 after the terminal lugs or tabs have been welded on;

FIG. 3 is a cross-sectional view taken substantially along the line 33 of FIG. 2, the vitreous enamel being shown;

FIG. 4 is a fragmentary view of a resistor showing a different type of terminal lug or tab;

FIG. 5 is a view similar to FIG. 4 showing another type of tab or lug;

FIG. 6 is a sectional view of a resistor and the jaws for clamping the terminal band extension and the terminal lug prior to welding thereof; and

FIG. 7 is a view similar to FIG. 6 taken as the terminal lug or tab is being welded to the band projection.

Attention first is invited to FIGS. 1-3 for an understanding of the invention. The resistor, generally identified by thenumeral 10, comprises a ceramic core 12 on which is wound a wire resistance element 14. The wire is welded or otherwise secure-d at both ends

toterminal bands

16 and 18 as indicated at 20. The bands comprise strips of sheet metal which are bent around the core to conform closely therewith, and which have upstanding,

integral extensions or

projections

22 and 24, these projections comprising the ends of the bands bent upwardly and spot welded together as indicated at 26 in'FIG. 3.

The resistor is shown in, FIG. 1 before welding of the terminal lugs or tabs thereon, and it will be appreciated that the outer ends of the

projections

22 and 24 are clipped off after'firing of the enamel to present clean welding surfaces 28 and 30. The terminal lugs or

tabs

32 and 34 are illustrated in FIG. 1 before attachment to the integral tabs or lugs. The completed resistor is shown in FIG. 2 with the tabs or lugs respectively butt welded to the clean welding surfaces 28 and 30 respective- 1y. The tabs or

lugs

32 and 34 are respectively provided with

apertures

36 and 38 for receipt of terminal wires. A cross-sectional view of the entire resistor is shown in FIG. 3 including the glazed vitreous coating 389 thereon, this coating preferably being of vitreous enamel, but it will be understood that the coating could be of any other suitable or known material, particularly such a material as might be stabilized by the application of heat.

A fragment of a resistor similar to that previously described is shown in FIG. 4, this resistor and the parts thereof being identified by numerals previously utilized with the addition of a suifix a. The resistor 10a again comprises a ceramic core 12a and a wire resistor element 14a wound on the core, Only one of the terminal bands 16a is illustrated with the wire connection 20a thereon. The integral projection 22a remains as before. However, in this resistor a terminal lug or tab 32a of somewhat different configuration and having an aperture 36a therein is butt welded onto the clean, clipped end of the projection 22a. The lug or tab 32a is illustrated as being larger than in the previous embodiment, and it may also be of different material.

A further modification of the invention is illustrated in FIG. 5. In this figure the parts are generally similar to those previously disclosed, and are identified by similar numerals with the addition of the suffix b. Further description therefore is believed to be unnecessary except for terminal lugor tab 32b. In this instance the terminal lug or tab 32b is L-shaped, having a shank portion 40 which is butt welded to the clean, clipped end of the projection 22b, and also having a laterally projecting foot 42 in which there is located an aperture 36b. It will be evident upon inspection of FIG. that the tab or lug shown therein is adapted for installations of different types than those previously illustrated.

The manner in which the terminal lugs or tabs are welded on the projections 22 is illustrated in FIGS. 6 and 7. The welding is illustrated with regard to the resistor embodiment first disclosed. The same numerals are used as were used originally, and repetition of the description is unnecessary. A stud or arbor 44 projects through the center of the ceramic core 12 to support the resistor with the integral projection 22 thereon extending downwardly between a pair of

jaws

46 and 48, the former of which has a positioning lug or tooth 50 projecting into a complementary recess in the opposite jaw 48 to provide for positioning of the projection 22. It will be noted that the jaw where they engage the projection 22 are rather thin in a vertical direction for providing proper clearance. A pair of terminal lug or tab clamping jaws 52 is positioned beneath the previously noted

jaws

46 and 48, and comprises a left-hand jaw 54 having a recess 56 therein for receipt of one of the tabs or lugs, as 32. The right-hand or opposed jaw 58 is provided with a block or tooth 60 adapted to project into the recess 56 for clamping the terminal lug or tab therein. As will be apparent in FIG. 7 the

jaws

46 and 48 are brought toward one another to clamp the projection 22, while the

jaws

54 and 58 move toward one another to clamp the terminal lug or tab 32. The two sets of jaws and the arbor 44 then are relatively moved toward one another to butt the terminal lug or tab against the projection 22, and welding current is applied through suitable connections (not shown) to the jaws to weld the tab or lug on the projection.

It will be apparent that the resistor herein disclosed may be more economically manufactured than those previously known in the art inasmuch as only one size, or at most very few sizes, of terminal band need be kept on hand, yet a practically infinite number of terminal lugs or hands of various sizes, shapes and consistencies may be applied. The welded on lugs are never oxidized by the firing of the vitreous enamel coating, and therefore need not be cleaned. The clipped off ends of the integral band projections are absolutely clean so that the lugs or tabs readily can be butt welded thereon.

Although the invention has been illustrated specifically with regard to a resistor, it is contemplated that other types of electrical elements might have terminals similar to the novel terminals herein disclosed. It is to be understood that the specific examples herein shown and described are by way of illustration only. Various structural changes are possible and constitute a part of this invention insofar as they fall within the spirit and scope of the appended claims.

Iclaim:

1. A resistor comprising a core, an elongated resistive element wound on said core, a metal band on one end of said core electrically connected to said resistive .-ele.- ment and having a standard size relatively short adaptor portion extending away from said core whereby to adapt the resistor to the attachment of various types of terminals, a coating of heat-stabilized insulating material on said core, resistive element and band; the outer end of said relatively short adaptor portion being free of said coating and oxidation incident to heat-stabilization thereof, and a terminal having an oxide-free end separately butt welded to the oxide-free outer end of said relatively short portion to present a lead wire attachment portion projecting beyond the adaptor portion.

2. An electrical element comprising an insulating base, impedance means disposed on said base, a substantially uniform conductive band wound uniformly about said base and having the ends thereof joined together and projecting outwardly a relatively short distance from said base to provide an adaptor portion presenting a double wall thickness of the band material for the attachment of various types of terminals, said band being in electrical contact with said impedance means, and a terminal having an oxide-free end separately butt welded to the double wall thickness of the projecting ends of said band .to present a lead wire attachment portion projecting beyond the adaptor portion; said base, impedance means and band being covered by a heat-stabilized insulating material with the projecting ends of said band being free of said insulating material and of oxidation attendant upon heat stabilization thereof facilitating attachment of the terminal thereto.

3. An electrical element as claimed in claim 2, wherein the projecting ends of the band are welded together closely adjacent the coating with the free ends thereof clipped to present clean surfaces for attachment of the terminal thereto.

4. The method of manufacturing resistors of the type including a core and an elongated resistive element wound thereon; which method comprises applying a metal band to one end of the said core in electrical connection with the resistive element and with a relatively short projecting portion of said band extending outwardly from the core providing an adaptor portion permitting attachment thereto of various types of terminals, coating the core, the resistive element thereon, and the band within the outer end of the projecting portion of the band with an insulation material, firing the insulation on the resistor with incidental oxidation of the projecting portion of the band, removing the oxide coating from the outer end of the projecting portion of the band to expose a clean metallic surface free of the effect of oxidation resulting from firing of the insulation, and welding an oxide-free end of a'terminal to the clipped clean metallic surface of the projecting portion of the band to elongate the projecting portion and provide a lead wire attachment terminal free from oxidation incident to firing of the insulation on the resistor.

5. The method of manufacturing resistors of the type including a core and an elongated resistive element wound thereon;-which method comprises applying a metal band to one end of the said core in electrical connection with the resistive element and with a relatively short projecting portion of said band extending outwardly from the core providing an adaptor portion permitting attachment thereto of various types of terminals, coating the core, the resistive element thereon, and the band within the outer end of the projecting portion of the band with an insulation material, firing the insulation on the resistor with incidental oxidation of the projecting portion of the band, clipping the outer end of they projecting portion of the band to expose a clean metallic surface free of the eficct of oxidation resulting from firing of the insulation, and welding an oxide-free end of a terminal to the clipped clean metallic surface of the projecting portion of the band to elongate the projecting portion and provide a lead wire attachment terminal free from oxidation incident to firing of the insulation on the resistor.

6. The method of manufacturing resistors of the type including a core and an elongated resistive element wound thereon; which method comprises applying a metal band to one end of the core in electrical connection with the resistive element and with relatively short extremities of the band extending outwardly from the core in abutting relation to form a relatively short projecting portion providing an adaptor portion permitting attachment thereto of various types of terminals, welding together the abutting extremities of the band relatively close to the core, coating the core, the resistive element thereon, and the band within the outer end of the projecting portion of the band with an insulation material, firing the insulation on the resistor with incidental oxidizing of the projecting portion of the band, clipping the outer ends of the extremities of the projecting portion of the band exteriorly of the Welded connection between said extremities to expose a clean metallic surface free of the effect of oxidation resulting from firing of the insulation, and welding an oxide-free end of a terminal to the clipped clean metallic surface of the projecting portion of the band to elongate the projecting portion and provide a lead wire attachment terminal free from oxidation incident to firing of the insulation on the resistor.

7. The method of claim 4, wherein the short projecting portion of the band serves as a surface to be gripped in supporting the resistor for attachment of the terminal thereto.

8. An electrical element as claimed in claim 3, wherein the separately attached terminal is of a single thickness of material with the double wall thickness of the projecting ends providing a relatively wide base portion for butt welding of the terminal thereto.

References Cited by the Examiner UNITED STATES PATENTS 1,830,084 11/1931 Bjornd-al 29155.69 1,932,923 10/ 1933 Bullin-ger 338329 2,043,196 6/ 1936 Finlayson 29-15569 2,402,122 6/1946 Bullinger 29-155.71 2,413,043 12/ 1946 Ganc-i 338329 2,636,963 4/1956 Wakefield 33 8-329 2,666,120 '1/19'54 Chanowitz 338--329 2,667,606 1/1954 Rood et al 33927 5 2,675,453 4/ 4 El-lin 219101 2,739,212 3/19'56 Woolley et a] 29-15569 2,820,076 1/195'8 Lillienberg 338329 RICHARD M. WOOD, Primary Examiner.

R. K. WINDHAM, Examiner.

Claims

1. A RESISTOR COMPRISING A CORE, AN ELONGATED RESISTIVE ELEMENT WOUND ON SAID CORE, A METAL BAND ON ONE END OF SAID CORE ELECTRICALLY CONNECTED TO SAID RESISTIVE ELEMENT AND HAVING A STANDARD SIZE RELATIVELY SHORT ADAPTOR PORTION EXTENDING AWAY FROM SAID CORE WHEREBY TO ADAPT THE RESISTOR TO THE ATTACHMENT OF VARIOUS TYPES OF TERMINALS, A COATING OF HEAT-STABILIZED INSULATING MATERIAL ON SAID CORE, RESISTIVE ELEMENT AND BAND; THE OUTER END OF SAID RELATIVELY SHORT ADAPTOR PORTION BEING FREE OF SAID COATING AND OXIDATION INCIDENT TO HEAT-STABILIZATION THEREOF, AND A TERMINAL HAVING AN OXIDE-FREE END SEPARATELY BUTT WELDED TO THE OXIDE-FREE OUTER END OF SAID RELATIVELY SHORT PORTION TO PRESENT A LEAD WIRE ATTACHMENT PORTION PROJECTING BEYOND THE ADAPTOR PORTION.