US1950508A - Combination resistor - Google Patents

Description

,Mall'l 13, 1934- J. L. MCWEENY 1,950,508

COMBINATION RESISTOR Filed April 13. 1931 Patented Mar.. 13, 1934 UNITED STATES COMBINATION RESISTOR John L. McWeeny, Chicago, 111-., assignor, by mesne assignments, to The Muter (Jompany,7 Chicago, Ill., a corporation o! Illinois Application April 13,

2 claims.

My invention relates to resistors and more particularly to a novel form of combination inductive and non-inductive resistor comprising single mechanical unit.

It is well known that in the building of radio equipment and other electrical devices of a similar nature, a large number of resistances are necessary in different phases of the various circuits therein. It has. been the common practice to provide a single resistor for each resistance required, and to dispose the same on the chassis at the most desirable point from the standpoint of assembling efficiency. It is obvious therefore, that in a radio of complicated construction, a relatively large number of such resistors may be necessary, and being disposed at various points about the chassis tend to increase both the cost of the device and cost of assembling due to the labor involved in attaching and soldering each individual resistor in its proper place.

It has also been found desirable in many instances, to provide both the inductive or wire wound type of resistor and also the. non-inductive orcarbon type resistor in the same assembly. This for the reason that it is mechanically7 impractical to eflciently manufacture an accurate resistor of the non-inductive type below, for example, three or four thousand ohms resistance. Where a lower resistance is desired, the inductive or wire wound type is often found desirable, and such resistors can be manufactured as low as several hundredths of an ohm resistance. In. many instances where an accurate resistance of over three or four thousand ohms is desired, the carbon type` is preferred because of the possibility of obtaining the greatest amount of resistance in the minimum of space.

In addition, it is well known in the trade that a wire wound or inductive type of resistor is capable of carrying several times more current than the carbon type of same cross section without ythe danger of overloading and consequent burning out. It is evident therefore, that in the assembly of thel common radio apparatus of today, a large number of factors must beV considered, involving the usekof several sizes of both inductive and non-inductive resistors, and among the inductive resistors, a number of y sizes of wire in as many resistors is desirable to 193'1, serial No. 529,574

It is a further object of my invention to pro vide a construction of these two types of resistances which permits the manufacture and preparation of the separate units in large numbers, and later inserting them within a unit of several resistances according to the amount of ohmage desired, or according to the wattage it is desired to dissipate. In this manner the various resistances utilized in a combination unit can be each individually pre-tested, .and when the final product is tested for accuracy, it will be found to come Within the limits of plus or minus allowed by the specifications, and it will not be necessary to reject the combination unit simply because one of the resistances is inaccurate, as is at present frequently the case.

My invention will be more readily understood by reference to the accompanying drawing, in which:

Fig. 1 is a top plan view of a combination resistance unit constructed in accordance with my invention;

Fig. 2 is a side elevation thereof, showing the metal housing in section;

Fig. 3 is a vertical sectional view taken on the lines 3 3 of Fig. 2 after unit has been enclosed.

Fig. 4 is a perspective view of the one-piece metal terminal clip of my invention, and

Eig. 5 is a perspective view of the spring clip' applied to the resistance units.

By reference to the drawing it will be seen that the combination unit of my invention comprises a plurality of pre-formed and pre-tested resistance units 10, 11, 12 and 13` placed in an end to end relation within an insulating jacket 14, which fits within a metal housing 15, having the fingers 16 formed on the ends thereof, which may be bent and inserted within apertures in a chassis, if desired. I may also prefer to provide the vapertures 16a in the ends to permit rivets or bolts to be inserted. As shown in Fig. 1 the resistances 10, 11, 12 and 13 are made up of alternate individual pre-formed units of the carbon or non-inductive ty-pe and the wire wound or inductive type for the purposes desired within any particularly electrical circuit. The non-inductive resistance units are formed in the manner describedand claimed in my co-pending application, Serial No. 529,573,

led April 13, 1931, as best shown in Fig. 3.-

These units, indicated by 10 and 12 in Fig. 1 are formed over a non-conducting base 17 h aving one face ground to a true plane surface and having the resistance material 18 applied thereon.

Thereafter the spring clip 19, best shown in Fig. 5 is applied thereover at desired intervals. Thereafter the carbon unit so formed is treated with a moisture resisting fluid 20 which is later removed from the face of the clips 19 to provide for electrical contact with the terminal clips generally indicated by 20.

The terminal clips, as best shown in Fig. 4 are formed of a single length of metal, having an upstanding terminal portion 21 and arms 22 and 23, formed at right angles thereto at a suitable distance from the end thereof. The arm 23 is formed out of the material of the arm 22. In the initial bent position the extremities 24, 25 of the arms 22 and 23 are intended to lie substantially parallel to each other and in the same plane with the upstanding portion 21. When the terminal clip 20 is applied to the treated base 16 having the spring clip 18 thereon, the extremity 24 of the longer arm is intended to be bent over the other to lie on the 'opposite face of the unit and substantially parallel to the arms 22, 23. Likewise the extremity 25 is adapted to be rebent and to substantially intert with the cut out portion 26. Thus in a single strip of material I have provided an extremely eicient contacting clip which is readily applied and when closed is practically immovable on the unit.

After the application of the terminal clips 20, the unit is set into a non-conducting jacket 14 and metal housing 15 having the screw or rivet apertures 15a, which is thereafter closed, as shown in Fig. 3. The nal opeiation consists in spraying or dipping the unit in another bath 27 of moisture resisting material which serves not only to exclude the moisture, but also in keeping outforeign matter that may seek entrance through the top or ends of the unit.

The inductive units l1 and 13 may be formed in any one of the several manners depending upon the purpose of the units within the circuits. The inductive resistances may be formed of similar or different sizes of resistance Wire, depending on the resistance desired within a given length of material or, they may be wound with a different number of turns per inchof a particular size of wire. If desired, the spring clips 19 may be applied to the inductive types, thus serving as a guide for positioning of the terminal clips 20 and to avoid the necessity of further testing of the particular unit. It is Well known that due to a large number of circumstances, involving the dimensions of the base or cross section and chemical makeup of the wire, the units must. necessarily be individually tested regardless of the use of a template in positioning the contacting clips. If desired, the terminal clips 20 may be applied directly to the wire without the use of the spring clip 19, in which event I prefer to utilize an apparatus disclosed in my copending application, Serial No. 519,382, filed March 2, 1931 which issued as Patent 1,870,462, Aug. 9, 1932.

It is obvious from the foregoing description that by means of the use of inductive and noninductive resistance units within a single housing, and by application of terminal clips at suitably spaced intervals on individual units, a large number of resistances may be had Within a single, central housing, being readily1 accessible for adjustment or repair, as well as Ainsuring the utmost economy in the original assembly of the electrical device. It is obvious also that by means of the construction hereindescribcd, the various resistances incorporated in the device may be manufactured in large numbers and tested to a particular value of resistance, and the combination unit as herein described can be assembled readily by the mere use of the preformed and pre-tested individual units, rather than the necessity of forming each of the resistances desired for a particular unit in the nature of a tailor made unit.

A number of modifications and variations in the device herein described will doubtless occur to those skilled in the art, and I do not Wish to be limited except as indicated in the appended claims.

I claim: .1. A resistor unit of the class described com prising an inductive resistance including a at strip of insulating material, a length of resistance Wire wound thereabout, and terminal clips secured to said winding of wire at selected intervals, a non-inductive resistance including a second fiat strip of insulating material shaped similarly to the first named strip and having a plane surface to receive resistance material, an electrical resistance material disposed over such plane surface of said second strip, a coating of moisture resisting material over such material and the second strip, and terminal clips on said strip and connected electrically to said resistor material at selected spaced intervals longitudinally of said strip, a thin sheet of insulatory material folded longitudinally to form a closure for said strips, the ends of said sheet overlapping and having a longitudinal opening therebetween, and a housing of highly conductive metal shaped about said strips, clips, and sheet, said housing having a longitudinal opening, said rst and second strips being disposed in spaced end to end relationship within said folded insulatory sheet with the ends of said terminals projecting from the longitudinal opening thereof, said metal housing being disposed over said folded body with the longitudinal opening therein coinciding with the longitudinal opening in said sheet and clamping said strips, said clips and said sheet in assembly.

2. A resistor unit of the class described comprising one or more inductive resistances each including a flat strip of insulating material, a length of resistance wire wound thereabout, and terminal clips secured to said winding of wire at selected intervals, and one or more non-inductive resistances each including a second flat strip of insulating material shaped similarly to the first named strip or strips, electrical resistance material upon the second strip or strips, a coating of moisture resisting material over such material and the second strip or strips, and terminal clips on said strip or strips and connected electrically to said resistor material at selected space intervals longitudinally of said strip or strips, a thin sheet of insulatory material folded longitudinali. to form a closure for said strips, the ends of said sheet overlapping and lhaving a longitudinal opening therebetween, and a housing of highly conductive material about said strips, clips and sheet, said housing having a longitudinal opening, said first named and second named strips being disposed in spaced end to end relationship Within said folded insulatory sheet with the ends of said terminals projecting from the longitudinal opening thereof,

said metal housing being disposed over said folded body with the longitudinal opening therein coinciding with the longitudinal opening in said sheet and clamping said strips, said clips and said sheet in assembly.

JOHN L. McWEENY.

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