US3363210A - Coil and spool and an improved method of making a coil - Google Patents

Description

Jall- 1968 J. s. HOLLYDAY 3,363,210

COIL AND SPOOL AND AN IMPROVED METHOD OF MAKING A COIL Filed July 6, 1965 United States Patent 3,363,210 COIL AND SPOQL AND AN IMPROVED METHOD OF MAKING A COIL Joseph S. Hollyday, Pennington, NJ, assignor to Heinemann Electric Company, Trenton, N..'l., a corporation of New Jersey Filed July 6, 1965, Ser. No. 469,590 12 Claims. (Cl. 336-485) ABSTRACT BE THE DISCLQSURE This invention provides a spool for a relay coil which has a channel at one end defined by two flanges, the channel being notched at the entry end to define for a starting end wire a side entrance to the channel and the channel receiving lead wires which are wedged into the channel so that any mechanical pull on the lead wires is transmitted to the spool.

Background of the invention An electrical coil, particularly a voltage relay coil, that is, a relay coil which has substantially the full voltage of the circuit across the coil is subjected to high dielectric stresses and this is especially true during overvoltage surges. The point of maximum voltage stress is the point where the windings starting end wire passes by the other layers of the winding. Since the insulation of the wires of a winding of a coil is kept to a minimum, an electrical breakdown may occur at this point between the starting end wire and the other windings of the coil. Further the leads of the coil may be subjected to a mechanical pulling or twisting during handling and installation. It is, therefore, an object of this invention to provide an improved coil arrangement for minimizing or preventing the aforementioned electrical breakdown and for securing leads to the wire forming the winding, and arranging them relative to the spool, together with an improved spool construction, so that any mechanical force imposed on the leads will be substantially transferred to the spool.

Summary of the invention In this invention, the starting end wire of the winding and the starting lead wire is inserted in a channel formed at one end of the spool between two flanges. The channel is open to the main portion of the spool at the level of the inner layer of the winding. Thus, the starting end wire and the starting lead wire are separated from the upper layers of the winding by the inner of these two flanges whose thickness and material, preferably nylon, is suflicient to withstand any voltage stress that may occur. Further, no abrasion of the starting end wire can occur as the inner flange effectively separates it from the end turns of the winding.

As is the custom in the prior art, it is common to attach to the end wires of the winding, because they are i usually of small diameter, wires of much greater diameter and with thicker insulation, commonly called leads. This is done to provide leads which will be resistant to breaking due to tension, twisting, crushing or other mechanical abuse and to get higher resistance to dielectric break down between them. In this invention, the lead wires are placed in the channel formed by the two flanges of the spool and the channel is turned upon itself and since the flanges, in the preferred embodiment, are approximately rectangular, the channel forms approximately a three quarter turn around the spool. The insulation of the lead wires is of such a size that the lead wires fit the channel tightly and are preferably taped in place. Thus, any mechanical pull on the lead wires is transmitted to the spool, because of the tight fit and the three-quarter 3,363,210 Patented Jan. 9, 1968 turn, and the spool is of suflicient size and strength to resist this pull.

The foregoing and other objects of the invention, the principles of the invention, and the best mode in which it is contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

Brief description of the drawings In the drawings,

FIG. 1 is a front elevation illustrating a spool incorporating this invention;

FIG. 2 is a side view, taken along the line 22 in FIG. 1;

'FIG. 3 is a partial back view of the spool illustrated in FIG. 1, taken along the line 33 in FIG. 2;

FIG. 4 is a perspective and partly diagrammatic view with a portion of the spool being cut away to illustrate initiation of the winding of the wire onto the core;

FIG. 5 is a view similar to FIG. 4, but illustrating the spool and the winding after the finishing lead has been secured to the finishing end wire;

FIG. 6 is a view similar to FIGS. 4 and 5, but illustrating the coil after the starting lead wire has been secured to the starting end wire;

FIG. 7 is a view similar to FIG. 6, but illustrating the coil after the starting lead wire and finishing lead wire have been placed in the channel but before the channel has been completely covered by an insulating tape; and

FIG. 8 is a partial sectional view taken along the line 8-8 in FIG. 7.

Description of the preferred embodiment Referring to the drawings, FIGS. 1, 2 and 3 illustrate a spool or bobbin '10 of electrical insulating material, preferably nylon, of a coil 21, FIG. 7. The spool 16 comprises a hollow spindle or core 12 having a flange 14 at the left hand end, as viewed in FIG. 1, and a pair of tfianges 16 and 18 at the opposite, right hand end, as viewed in FIG. 1. V

The outer surface 19 of the core and the opposed surfaces of the flanges 14 and 16 define a space for receiving a suitable number of turns of insulated wire to form a winding 20, FIGS. 4 and 5.

The flanges 16 and 18 with a bottom wall 213 define an elongated channel 25 in which are receivedstarting and finishing lead wires 27 and 29, respectively. The channel 25 has open ends 40 and 41 and is also open along its peripheral (radially outermost) extent, as shown in the drawings.

The flanges 14, 16 and 18 are all integral with the core 12, the core 12 and the flanges 14, 16 and 18 being generally rectangular in cross sectional shape. The flange 14 is complete in a peripheral sense, but the flange 16, however, is cut away at one corner to form a notch 31 defining an entry for the windings starting end wire 33 into the channel 25. One of the shorter sides of the flange 18 may be omitted, as illustrated, and the bottom wall extended, as at 30 and 32, to form a recess 35, so that part of the magnetic laminations (not illustrated) with which the coil 21 is associated may be received in the recess 35.

The bottom wall 23, which connects the flanges 16 and 18, extends generally at right angles to the flanges 16 and 18, The wall 30 has an entry surface 36 which is coplanar with one of the surfaces, the surface 37, of the core 12, and the surface 36 is joined to the main surface 44 of the wall 23 by an inclined surface 45.

The winding 20 of insulated wire is formed on the spool 10 by taking the windings starting end wire 33 and placing it in section A of the channel 25, as illustrated in FIG.

4, and a part of the starting end wire 33 is temporarily taped to the flanges 16 and 18, as shown by the tape 50.

The starting end wire 33 is placed on the bottom wall 23 of channel section A, upon the entry surface 36, and is wound about the surface 19 of the core in the direction indicated by the arrow in FIG. 4 for as many turns as is desired. After a sutficient number of turns of wire have been wound about the core, an elongated flat, thin insulator tape 52 is placed on the winding 20 as shown. At one end of the winding 20 the windings finishing end wire 53 is taped in place upon the insulator 52 by a narrow piece of insulating tape 56. The finishing end wire 53 is taped in place by the tape 56 with a length of the finishing end wire 53 extending upon the insulator 52. The extreme left end of the lead wire 29 is then soldered to the finishing end wire 53. Thereafter, the lead wire 29 is taped to the winding by the first turn of the tape 60. The major portion of the lead wire 29 being free, as shown. In FIGS. 5 and 6, for case of illustration, the lead wire 29 has been foreshortened, as indicated at D.

Thereafter, referring to FIG. 6, the temporary tape 50 which secured the starting end wire 33 to the flanges 16 and 18, shown in FIG. 4, is removed. The windings starting end wire 33 is then cut to proper length, if necessary, and soldered to the starting lead wire 27.

The starting lead wire 27 and. the starting end wire 33 are long enough so that the soldered joint between them can be made outside of the channel 25. After the starting end wire 33 has been soldered to the starting lead wire 27, the starting end wire 33, the soldered joint and the starting lead wire 27 are placed in the channel25, as illustrated in FIG. 6. The solder connection between the starting end wire 33 and the lead wire 27 is placed in the channel section A to the right of the notch 31 so that it is separated from the windings by the flange 16 to prevent abrasion of the windings by the soldered joint. The end wire 33 comes off of the solder connection at the latters right hand end so that the end wire 33 loops, as shown in FIG. 6.

The starting lead wire 27 is first placed in the channel section A and then placed sequentially in channel sections B and C. On top of the starting lead wire 27 is placed the finishing lead wire 29, as illustrated in FIG. 8. The winding 20 is then covered with a suitable number of turns of the insulating tape 60, FIG. 7. Preferably, the flanges 16 and 18 are also covered with turns of the insulating tape 60, and FIG. 7 shows the flanges 16 and 18 about to be covered.

The channel 25 is of rectangular cross sectional shape, FIG. 8, and deep enough so that the two lead wires 27 and 29 may be placed one on top of the other within the channel 25 with no part of the upper lead wire 29 extending substantially beyond the (radially outermost) peripheral surfaces of the flanges 16 and 18. Since the channel 25 is deeper at the inclined surface 45, a pocket is provided to receive the soldered joint between the starting end wire 33 and the lead wire 27 so that the soldered joint is slightly spaced from the adjacent portion of the lead Wire 29. It is seen in FIG. 7 that the end wire 33 is spaced below the adjacent overlying portion of the lead wire 29. Thus, abrasion between the soldered joint and the lead wire 29 is minimized.

Further, by inclining the wall 45, as illustrated, a wall of greater thickness results between the flanges 16 and 18 than if the thickness of the extension 30 was continued for the entire length of the wall 23. Also, by raising the surface 44 relative to the surface 36, the upper part, as viewed in FIG. 8, of the lead wire 29 is exposed to the tape 60, assuming the tape 60 is placed across the flanges 16 and 18, to further strengthen the coil.

The width of the channel 25 is such that the leads 27 and 29 are snugly and tightly received within the channel. Preferably, a small amount of force is required to press the leads 27 and 29 down into the channel, the outside diameter of the insulation of the leads 27 and 29 being just slightly greater than the width of the channel. After the leads are placed in the channel, or before, the leads 27 and 29 are cut to length to suit and connector lugs may be soldered to them, but are not illustrated.

Since the three sections A, B and C of the channel 25 are turned upon themselves, i.e., the section B is at approximately 90 to the section A and the section C is also at approximately 90 to the section B, forming generally a channel 25 of U-shape when viewed endwise, FIG. 2, any pull on the leads 27 and 29 will not be transferred to the winding but will tend to cause the part of the leads in the section B to jam further inwardly. This, together with the fact that the width of the channel 25 is slightly less than the outside diameter of the insulation on the leads, transfers any force on the leads to the spool 10. Although the spool 10 has been illustratedand described as generally rectangular in cross section, it is seen that this invention is applicable as well to other shapes for the spool, such as circular, for example. a

To further separate the soldered joint between the starting end wire 33 and the lead wire 27 from the lead wire 29, the lead wire may be doubled back or hooked over so that the insulated part of the lead wire 27, shown in FIG. 6, just to the right of the soldered joint overlies the soldered joint and separates it from the overlying part of the lead wire 29.

Having described this invention, I claim:

1. A coil comprising aspool of electrically insulating material having a core and first, second and third end flanges, a winding of insulated wire on the core between the first and second of said end flanges, said winding having a starting end wire and a finishing end wire extending from the body of the winding, a bottom wall connecting the second and third flanges and therewith defining a channel at one end of said spool, said channel being open along its outer peripheral extent, said channel being turned at an angle to itself along its length, a starting lead wire and a finishing lead wire connected to the starting end wire and to the finishing end wire, and portions of the lengths of said lead wires being disposed in said channel with at least one of the lead wires in wedgin-g relation with portions of the flanges.

2. The structure recited in claim 1 wherein said second flange is notched at the entry end of the channel to define for the starting end wire a side entrance to said channel, and said bottom wall has a top surface coplanar with the contiguous surface of the core at the entry end of the channel.

3. The structure recited in claim 2 wherein said core has a generally rectangular shape in cross-section and said flange being turned upon itself in a U-shape and said notch is located at a corner of said second flange.

4. The structure recited in claim 3 wherein the part of the bottom wall between the second and third flanges increases gradually to a greater thickness than the thickness of the part of the bottom Wall between the notch and the third flange.

5. The structure recited in claim 4 further defined by said channel being wide enough and deep enough in cross-section to accommodate both lead wires without any of said lead wires extending radially outwardly of said channel.

6. A spool of electrically insulating material having a core and first, second, and third end flanges, a bottom wall connecting the second and third flanges and therewith defining a channel at one end of the spool, said channel being open ended and open along its outer peripheral extent, said channel being turned at an angle to itself along its length, said second flange being notched at the entry end of said channel to define for a starting end wire a side entrance to said channel.

7. The structure recited in claim 6 wherein said channel has a U-shape and said bottom wall has a top surface coplanar with the contiguous surface of the core at the entry end of the channel, the open ends of the channel being formed by the ends of the U-shape.

8. The structure recited in claim 7 wherein said core and flanges have a generally rectangular shape in crosssection and said notch is located at a corner of said second flange.

9. The structure recited in claim 8 wherein the part of the bottom Wall between the second and third flanges increases gradually to a greater thickness than the thickness of the part of the bottom wall between the notch and the third flange.

10. The method of making a coil comprising a spool and a winding comprising placing a starting end wire in a channel of the spool, temporarily securing a part of the starting end wire to the spool, forming a Wire winding on the spool, placing an insulator on the winding, laying the finishing end wire on the insulator, soldering the finishing end Wire to the finishing lead Wire, securing a part of the finishing lead Wire to the winding by covering said Winding and a part of said lead wire with insulating tape, unsecuring said starting end wire from its temporary attachment to said spool, soldering said starting end wire to said starting lead Wire, placing said starting end wire and forcing a part of said starting lead wire into said channel, and forcing a part of said finishing lead wire into said channel.

11. The method of making a coil comprising a spool and a Winding comprising forming a wire winding on the spool, soldering the finishing end wire to the finishing lead wire, securing a part of the finishing lead wire to the winding by covering said winding and a pait of said lead wire with insulating tape, soldering said starting end wire to said starting lead wire, placing said starting end Wire and forcing a part of said starting lead Wire into a channel, and forcing a part of said finishing lead Wire into said channel.

12. The method of making a coil as recited in claim 10 and modified by securing the finishing end wire to the insulator and winding with a part of the finishing end wire being exposed and overlying the insulator, and thereafter soldering said finishing end wire to the finishing lead wire.

References Cited UNITED STATES PATENTS 2,661,446 12/1953 Adcock 29-115.5 X 3,117,294 1/ 1964 Muskynski 336-2 O8 X 3,230,489 1/1966 Weyrich 336-208 X 3,265,999 8/1966 Kessel 336-192 LEWIS H. MYERS, Primary Examiner.

E. GOLDBERG, Assistant Examiner.

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