US 2464820 A
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March 22, 1949. A. l.. LIVERA MULTIPLE COIL WOUND RESISTOR Filed April 1945 Wh 7 j D, HM............
l N VEN TO R ldo ZI.- Z. wra/ ATTORNEYS Patented Mar. 22, 1949 MULTIPLE COIL WOUND RESISTOR Aldo L. Livera, Madison, N. J., assigner, by mesi-ie assignments, to John G. Ruckelshaus Company, a corporation of New Jersey Application April 5, 1945, Serial No. 586,805
a claims. 1
This invention relates to coil wound elements, particularly to an interconnected assembly of individual coil-wound impedance elements, and has for an object to protect the interconnecting leads between said individual elements.
In the manufacture of multi-coil impedance elements having a plurality of spools or coils which form integrated multi-ribbed spools, it has been the practice in wiring the entire element to run the wire from one terminal through a slot in a rib or flange forming a side of the spool, down the inner face of the ange, several turns being wound around a core to secure the lead-in wire in position and then winding the required number of turns on the core to form the usual coil. After the coil has been completed in the rst spool, the wire is led through a. similar slot in the adjacent flange for the second spool and the above winding process is repeated, etc., until all spools have been wound, after which'the end of the wire is secured to its corresponding terminal.
It has been found that opens often occur in impedance elements manufactured in the above manner, lparticularly when the element is subjected to wide ranges of temperature, as well as humidity, and investigation has revealed that the opens generally appear in the leads interconnecting the adjacent spools. The investigation further reveals that the interconnecting leads upon completion of the winding operation are substantially taut even though suilicient slack in the wire was provided initially, the tautness of the wire being brought about by the fact that in winding a coil the various layers of wire contiguous to the interconnecting lead force it against the face ofthe flange, thereby taking up the slack. Furthermore, a certain amount of abrasive action is produced by the rubbing of the contiguous superposed coil wires against the interconnecting lead, so that the insulating medium therearound is partially removed at the contact area thereof, thereby encouraging deterioration, corrosion, and eventual breakage of the wire.
It is therefore another object of the invention to provide a simple and economical coil-wound impedance element free of the above manufacturing defects.
It is still another object of the invention to provide an improved coil-wound impedance element in which suicient slack is assured for the lead-in and spool-interconnecting Wires.
It is a further object of the invention to lprovide an improved coil-wound impedance element substantially impervious to-huinidity conditions.
With the above objects in view, one embodiment of the invention discloses a multi-spool coil form having a plurality of concatenated coils in which the lead-in and coil-interconnecting wires are assured a predetermined amount of slack by adhesively securing them to the inner spool flange surfaces, whereby these wires are also protected against abrasive contact by the superposed layers of wire.
A more complete understanding of this invention will be obtained from the detailed description which follows and by reference to the a-ppended drawing in which:
Fig. 1 shows a perspective view of a multi-coil impedance element,
Fig. 2 shows an enlarged sectional View of the impedance element taken along line 2-2 of Fig. 1, and
Fig. 3 shows a sectional view of one of the coil forms taken along line 3 3 of Fig. 2.
Referring now to the drawing, particularly Figs. 1 and 2, there is shown an impedance element I0, such as a resistor of the multi-spool type, comprising a cylindrical core II with intermediate and outer flanges or walls I2, I3, respectively, integral thereto for forming the core II into a series of interconnected spools within each of which a wire-Wound coil I4 is contained. The core II. which may consist of any suitable insulating material, such as Isolantite, may also be provided with an axial bore I6 for equipment-mounting purposes. Each of the flanges I2 and I3 is provided with aradial slot I'I, transversely therethrough, the several slots preferably being in alignment. Radial slots I'I are provided in the inner flanges I2 for passage therethrough of Ithe coil-interconnecting leads I8 while the radial slots II in the end anges I3 are provided for the lead-in wires I9, which are connected to terminals 2| in aimanner to be described hereinafter.
In manufacturing the impedance element in accordance with the invention, let it be assumed that the wiring, which may be insulated by any of the well-known insulating mediums, such as enamel, is initiated from the left side of the unit,
as viewed in Fig. 2. The lead-in wire I9 is ilrst connected to terminal 2| by the usual soldered collar 20 which, briefly, comprises winding several turns of the lead-in wire in a recess 22 formed in the core and applying a collar of solder thereto, whereby the terminal 2| and turns of wire I9, which ypreferably are rst tinned tc facilitate the soldering operation, are electrically and mechanically interconnected. The lead-in wire I9 is then passed through slot I1 of flange I3 and down the inner face thereof to the peripheral surface of core II. As shown in Fig. 2, the lead-in wire I9 is provided with a certain amount of slack, which is disposed within the slot I1. A few turns of the wire are then wound around the core a small distance away from the face of flange I3 to secure the wire in place, and the wire is then pushed back against the flange face to provide additional slack for the wire I9.
The next step comprises fastening the wire I9 to the side wall of the ange I3 by any suitable adhesive material, such as acetate tape 23, in a manner shown particularly in Figs. 2 and 3, the bulge of wire I9 in the slot I1 evidencing the approximate amount of slack. It can be readily seen that the adhesive tape 23 insures slack in the lead-in wire I9 and at the same time provides an additional insulating cover for the wire which is, therefore, protected from abrasions as the remaining turns of wire for the coil Il are wound on the core I I. The required number of turns are then wound around the core II and the interconnecting lead I8 from the flrst coil I4 is then passed through the slot I1 formed in the adjacent inner flange I2, and the procedure of securing the wire I8 by tape 23 is repeated to provide the reuuired amount of slack. It will be noted here that the adhesive tape 23 after being secured to the face 'of yflange I2 is continued over the peripheral outer edge of flange I2, over the slot I1 formed therein, partially down the other face of the flange I2 and across to the adjacent flange IT, where it is adhesively secured to the top of the previously-secured tape 23. The above winding process is repeated for the remainder of the individual spools, after which the lead-in wire I9 for the extreme right spool I4. as viewed in Fig. 2, is connected to its terminal 2| in a similar manner to that at which the left lead-in wire I9 was connectedl to its terminal 2|. Thus an impedance element comprising a series of interconnected coil windings is formed. The terminals 2| provide a suitable means for electrically connecting the impedance I to an external circuit not shown).
The final step in the manufacturing process comprises dipping the impedance element I0 into any of the well-known impregnating materials, whereby the element I0 is further fortified against insulation resistance breakdown. By placing the tape 23 o ver the slots I1, as described hereinbefore, it has been found that the impregnated material remains within the slots after the dipping operation. process the impregnatingmaterial did not adequately cover the wires I8, I9 in the slots I1, having dropped out of said slots I1 when the impedance element was removed from the impregnating compound. It is thus seen by virtue of the addition of the above tape 23 that a further advantage accrues to the manufacture of animproved impedance element I0 in accordance with this invention, namely, greater protection from an insulation resistance standpoint being provided for the interconnected and lead-in Wires In the prior manufacturing' I8, I9, respectively, whereby the impedance element I0 may be employed under situations where wide ranges in temperature and humidity are encountered.
While this invention has been shown and described as embodying certain features merely for the purpose of illustration, it is clear to anyone skilled in the art that many modifications are possible without departing from the spirit of the invention and the scope of the appended claims.
For example, while the invention has been described in connection with a multi-coil wound structure, it is, of course, to be understood that the invention may also be applied to a single coil wound impedance element.
Additionally, and also by way of example, it will be obvious to those skilled in the art that the advantages of the insulated tape as described above are equally applicable to resistors in which the flange between spools is not slotted, but, for example, ilattened or notched, and the lead from one spool to the other passes up, over, and down the flange sides. y
What is claimed is: v
1. An impregnated impedance element comprising an insulating core, a plurality of spaced radially-extending flanges integrally formed on said core, each of said flanges having a radial slot therein, a plurality of turns of wire wound on said core to form individual coils between adjacent flanges, said coils lbeing interconnected serially and being terminated in a pair of lead-in wires, said interconnecting and lead-in wires being extended through respective ones of said slots, a pair of terminals connected to said leadin wires, and an adhesive insulating tape adherently applied to each flange over each lead-in wire so as to cover said wire and secure it to the side face of the associated flange, whereby a predetermined amount of slack is 'provided for said wires in said slots, each insulating tape also being disposed over the slot in the associated flange for preventing loss of impregnating material from the slot, extended across to the next adjacent flange and adherently secured to the tape on said flange.
2. The method of manufacturing an electrical impedance element of the wired-spool type having at least a pair of flanges and a radial slot in each of said flanges which comprises securing a wire tofone end of the spool, passing the wire through one of the slots, securing the wire to the associated flange with a predetermined amount of slack provided within the slot by covering the slot and that portion of the wire extending therefrom along the flange with an adhesive element, winding a predetermined number of turns of wire around the spool, thereafter passing the wire through the slot of the other ilange and securing the wire to the other end of the spool.
3. The method of manufacturing electrical impedance elements of the wired-spool type having a core and at least a pair of flanges with a radial slot in each of said flanges which comprises securing a wire to one end of the spool, passing the wire through the slot in one of the flanges, extending the wire to the core at an angle to the flange, winding at least two turns around the core adjacent said flange, pushing these turns against the face of the flange to provide slack in the vwire in the slot, securing the Wire to the flange by applying adhesive tape thereto, covering the slot with the same portion of tape, thereafter winding a predetermined number of turns of wire upon the core, extending the wire through the slot of the other nange, and securing the wire to the other end of the spool.
ALDO L. LIVERA. REFERENCES CITED 6 The following references are of record in the i'lle of this patent:
UNITED STATES PATENTS Number Name Date 10 1,976,514 Pugh Oct. 9, 1934 2,047,798 Ogg July 14, 1930 2,286,161 Rights et ai June 9. 1942 neming t Johnson. Insulation and Design of Electrical windings, 1913.
Brunner. "Armature Winding and Motor Repair, 1920.