US2513421A - Process of manufacturing resistors - Google Patents

Description

July 4, 1950 A. MEON] 2,513,421

PROCESS OF MANUFACTURING RESISTORS Filed Jan. 27, 1948 HS PQEMT.

Patented July 4, 1950 Angelo 'Meoni, Paris, France, assignor to 'Societe 'a' 'responsabilite dite: Socit Castex, Paris,

, -Applicationflanuary 27, 1943, Serial No. 4,538

vIn :Italy October 23, 1946 Section L-Pu'blic Law 690, August 8, 1946 Patent expires October 23, 1966 1 Claim.

This invention relates to fixed-resistors of the type generally -used.-in connection with radioelectric circuits, and to the manufacture thereof.

The electrical resistor according to the invention consists of a resistance blade member provided with input and output-wires and sunk or embedded, together with the connecting points of said wires, into an insulating mass designed to impart the necessary mechanical strength to the assembly thus formed.

The manufacturing method employed consists broadly in obtaining, by cutting or stamping out from a suitable material in strip or band shape, a resistant small plate forming a plurality or set of parallel blades, securing to the ends of these blades the members adapted to function as input and output conductors, moulding around the blades and their connecting points with said conductors a thick mass of insulating material so shaped as to provide between adjacent or successive blades gaps or thin, readily broken portions and separating the thus formed individual resistors from one another.

According to the invention, the process is carried out by cutting out from a strip or band of suitable material, for instance, Bakelite-coated cardboard (previously treated so as to coat it with a mass or layer constituting an electrical resistance) a plurality of special apertures or holes spaced at regular intervals; then the current input and output wires or conductors are applied upon this strip and the latter is partially or totally passed into an appropriate mould wherein said strip is coated on both surfaces with an insulating material such as Bakelite, with a given thickness to ensure both the necessary mechanical strength and the electro-insulating protection.

A current resisting strip or band, may be cut or stamped to form the fastening member therein for the input and output wires; a conductor plate is stamped or cut to form at least one aperture therein having fastening or securing edges; the aforesaid resistance strip is positioned within the aperture and a suitable securing is made between the corresponding fastening members; then the resistance strip is cut so as to separate a series of parallel blades each of which will form a single resistor; an insulating material is mould.- ed. around the resistance blades and the conductor plate is subsequently cut off whereby input and output wires are separated from the input and output wires of the adjacent resistance element; both moulding and stamping operations may be carried out in any desired order or simultaneously if desired; finally, the individual resistors are separated from-each other.

The accompanying drawing illustrates diagrammatically and only by way of example, two

' embodiments of the invention} Fig. 1 is a front view of the "-Bakelised cardboard strip or plate of resisting material, so rendered through any suitable previous treatment;

Fig. 2 shows "the strip as provided with a regular set :of special -a-pertures and holes;

Fig. 3 shows the strip before it is introduced into the mould for Bakelite;

Fig. 4 is a perspective view of the strip already provided with its surrounding insulating mass, together with the electrical connecting wires;

Fig. 5 shows in axial cross-section, a resistor element obtained by separating it from the strip of Fig. 4;

Fig. 6 is a partial sectional view taken at right angles to Fig. 5 of the same resistor element;

Fig. '7 is an end view of two such elements, before they have been separated.

Referring particularly to the drawing, 1 is the Bakelised cardboard or similar material on which a layer of graphite, for example, was laid; 2, 2 are the apertures cut out from the strip I; 3, 3 are holes made in the strip between the solid portions left between two adjacent apertures 2, 2; 4, 4 refers to the pair of electric connecting Wires having one of their ends bent at right angles (4a, Fig. 5). This end is introduced into the corresponding hole 3 (see Fig. 3); fracture lines may be made in the strip by means of suitable punches which may be provided in the mould utilized for applying the insulating material (e. g. Bakelite) on the strip I with a proper thickness to impart sufficient strength to the strip while at the same time insulating every part and surface thereof which were previously made conductive.

Once the terminals to have been introduced into their respective holes, they may be riveted before the insulating materials 6 (Bakelite or any other suitable material) is moulded therein.

The insulating material 6 may be of synthetic resin or plastic material of any type provided that it posses the required electrical and mechanical characteristics.

The strip from which the various electrical resistors are obtained will preferably be made of a readily cut material. It may also consist of a band which may be sliced off during the manufacturing process.

The electrical resistance may be obtained not only by depositing or coating the sides or surfaces of the strip or band with an electrically refor resistors of small dimensions, since it affords the possibility of holding a plurality of resistors together during the various steps of the manufacturing process, thus permitting the different operations to be performed on groups of, say,

fifty or a hundred resistors at a time.

To further insure a firm contact between each conductor 4 and the surface I provided with an electrical resistance material, a conductive substance may be applied as in the form of a metal varnish. The folded end of the wire may be set or may carry a suitable thin washer.

The foregoing description has been made for ease in understanding the invention and not by way of limitation since the inventive principles involved are capable of execution in other than the manner specifically set forth herein without departing from the spirit of the invention and the scope of the appended claim.

What I claim is:

The method of manufacturing in mass production electric resistors for radio-electrical circuits which comprises combining with a sheet of material anelectrically resistant mass, cutting said sheet to form strips of a width substantially equalling the length of a resistor body, forming in such strip by stamping a row of parallelly spaced rectangular apertures of a length somewhat inferior to the width of said strip which are separated from each other by strip sections,

; placing part of a pair of conductive lugs on each strip section, covering both sides of said strip with a comparatively thick layer of insulating REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,702,062 S onkin Feb. 12, 1929 1,913,473 Brennecke June 13, 1933 1,972,411 Swartz et a1. Sept. 4, 1934 1,985,166 Haroldson Dec. 18, 1934 2,005,922 Stoekle a June 25, 1935 Benkelman Oct. 17, 1939

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