US1299585A - Ignition-coil. - Google Patents

Description

E. P. d: T. L. LEE.

IGNITION COIL.

APPLlcATIou min JULY 9.1911.

Patented Apr. 8,1919.

LVIIIAIIIIIIII lIIIIIIIIIIIIII UNITED STATES PATENT OFFICE EARLE P. LEE AND THOMAS L. LEE, OF ROCHESTER, NEW YORK, ASSIGNORS TO NORTH ELST ELECTRIC COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION 0F NEW YORK.

IGNITION-COIL.

Speccaton o1' Letters Patent.

Patented Apr. 8, 1919.

To all whom it may concern.'

Be it known that we, EARLE P. Lun and THOMAS L. LEE, citizens of the United States, residin at Rochester, in the county of Monroe an State of New York, have invented certain new and useful Improvements in Ignition-Coils; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it ap ertains to make and use the same.

his invention relates to an induction-coil suitable for use in producing the high-tension discharge used for ignitlon in internalcombustion engines.

Coils for the purpose in question are usually made with long straight cores, having high reluctance, in order to secure a sufliciently rapid response to the very short periods of ener 'zation available with highspeed multi-cy inder engines. Coils of this form are comparatively ineilicient, however, particularly at the lower engine-s eeds, and the require primary windings o such low resistance that if such a coil be subjected steadily to an E. M. F. equal to that by which it is intermittently ener ized when in use, the coil will be damaged y heating or the source of energy, if a battery, will be seriously depleted.

To secure a higher degree of efficiency than can be attained by a straight-core coil, it has been proposed to provide an ignitioncoil with a closed or substantially closed core aii'ordin a magnetic circuit of low reluctance. uch an arrangement has never gone into successful commercial use in connection with high-speed apparatus, so far as the present inventors are informed, and this is apparently due to various defects, both constructional and electrical, of coils of this type, when constructed in accordance with the practice prevailing in the manufacture of analogous apparatus such as commercial transformers, in which the closed cores are built up of punchings or laminations of sheet iron. y

The objects of the present invention are to produce an ignition-coil of the compact, inexpensive, eilicient and reliable character necessary for successful commercial use in connection with the engines of motor-vehicles, and to dispense with the necessity of resistance-devices or automatic cut-outs for 56 the protection of the battery and the coil from an accidental closed circuit when the apparatus is not in use.

It has been found that the foregoing objects may be attained, in an ignition-coil having a substantially closed magnetic circuit o low reluctance, by a construction and arrangement of parts such as to avoid the difficulties heretofore encountered in devices of this type, and articularly by a form and arrangement of tlli) constructed partly or wholly of iron wire in place of the lamine@ previously used for similar apparatus.

Other features of the invention, conducing to the desired result, will be set forth 1n the following description of a preferred embodiment of the invention.

In the accompanying drawings Figure 1 is a plan-view of an ignition-coil embodying the present invention; Fig. 2 is a side-elevation of the coil, with the casing and the terminal-insulators in section on the line 2-2 in Fig. 1; Fig. 3 is a vertical section of the coil-proper and the casing, on the line 3-3 in Fig. 1; and Fig. 4 is a detail-view, in plan, showin the relation of the tie-rod to the core-mem ers.

The invention is illustrated as embodied in an ignition-coil adapted for use in connection with the multi-cylinder high-speed engine of a motor-vehicle. This coil has a substantially closed magnetic circuit produced by the combination of two members which are hereinafter referred to as the core and the yoke-member.

The core l() is composed of parallel iron wires arranged in the form of a cylindrical bundle. The primary winding 11 is mounted upon and insulated from this core in the usual manner, and the high-tension secondary winding 12 surrounds the primary winding and the core.

The yoke-member above referred to is in the form of a continuous approximately rectangular ring, which constitutes, in effect, two yokes connecting the opposite ends of the core 10. This yoke-member is preferably formed of iron wire wound continuously on a suitable form, and at the corners of the yoke-member the turns of wire are held securely in correct relation by sheetsmetal clips l having lugs 15 which are bent around the edges of the core-member.

To prevent the discharge of high-tension current from the secondary winding to the e core such that it may beV yoke-member, the ends of the windings are covered by caps 16 of insulating-material.

The use of iron wire in place of lamina? of sheet-metal in the core and the yoke-mem ber has been found to have important advantages, relating both to electrical eliciency and to economy and simplicity in manufacture. A coil so constructed, when energized through a circuit-closer of the ordinary single-contact type, will give a spark of approximately constant length and intensity throughout a wide range of speeds.

In the matter of manufacture, the wire core has the important advantage that it may be made circular in cross-section, so as to conform to windings of similar form, whichmay be produced more easily and cheaply than windings of other forms, while requiring a minimum length of wire for a given number of turns. The wire yokemember is also easily and cheaply constructed; and the use of an endless yoke-member in combination with a straight core permits the windings to be formed separately, previous to the assembling of the core-members.

A feature of the invention resides in the simple and effective means used to secure the members hereinbefore described together in their proper relation, and to fix them in place in the casing which incloses them. For this purpose a tie-rod 17 is used, this rod passing through a tube 18 embedded axially in the core 10. The tie-rod is passed through the upper and lower parts of the yoke-member 13, and it has been found that this may be done.` without seriously distorting the yoke-member, by merely thrusting the rod between the turns of wire. The clips 14 prevent the wire from spreading to any undue extent, and the wire will crowd together, at either side of the tie-rod, so that little or no change in the width and the thickness of the yoke-member is produced by the introduction of the rod.

The ends of the tie-rod are threaded, and an oblong metal plate 19 is screwed to the lower end. A metal disk 20 and a nut 2l are mounted on the rod above the yokemember, and when the nut is screwed down the upper and lower parts of the yoke-member are drawn tightly, between the disk 2() and the plate 19, toward the ends of the core 10.

The lower end of the core is held in firm engagement with the yoke-member by the means just described, so as to produce a joint of low reluctance. Since the coil has been found to work better with a slight gap in the magnetic circuit, a spacingwasher 22 of insulating-material is interposed between the yoke-member and the upper end of the core.

The coil-proper is inclosed within a cas in and since the closed magnetic circuit su stantially eliminates magnetic leakage, it

has been found that this casing may be made of metal, and that it is not necessary to slot the casing or adopt any other expedient to prevent the occurrence of eddy currents. The casing may therefore be made ver sturdy and may be formed integrally witli the base or ilange by which it is mounted or supported, instead of being separatelyV formed as in the ordinary spark-coil, where the casing must be made of insulating Inaterial.

The illustrated casin comprises a body 23 with an open top. 'Illiis body is cast integrally with a late or flange 24 which serves as means or securing the coil to a suitable support, such for example, as the casing of the ignition-timing mechanism. The top of the body 23 is closed by a cover 26, upon which is seated a block 27 of insulating-material. The tie-rod 17 passes through the bottom of the casing and is secured by a nut `25, while the upper end of the rod passes through the cover 26 and the block 27, and'a nut 29 is screwed upon it. When the nut 29 is tightened against the block the block and the cover are clamped securely in place.

The block 27 serves as a mounting for the binding-posts through which connections are made with the primary winding of the coil. These posts comprise metallic inserts 30 embedded in the insulating-material and perforated to receive the binding-screws by which the primary terminal-wires 31 are secured. The cover 26 is perforated at two points to receive two depending portions 28 on the block, the inserts 30 being coaxial with these depending portions, which serve to prevent rotation of the block with relation to the cover. External connections may be made with the inserts in a similar manner, and the block 27 is providedwith two upwardly projecting semi-circular Ishields 32, which are oppositely disposed. This arrangement of the shields tends to prevent incorrect connections between external conductors and the coil, as such extern al conductors approaching the coil from opposite directions cannot, owing to the shields, be attached to the wrong bindingposts.

The outer terminal 33 of the secondary winding is mounted on the peri hery of the winding, as shown in Fig. 2. he casing 23 is provided with a neck 34 into which a lug 35 of insulating-material is screwed. ilhis plug carries a metallic insert 36 which constitutes a binding-post for an external hightension conductor. The usual nut 38 may be used for attaching such conductor. Connection is made between the terminal 33 and the post 36 by means of a coiled spring 37 which lies loosely in a socket in the ost and presses against the face of the terminal.y

An important advantage of the present construction resides in the provision which it aii'ords for carrying away heat enerated in the primar winding of the coi In ignition-coils o ordinary form the heat generated, in case of an accidentally prolonged closure of the circuit, is so great as to be injurious to the insulation, so that it is customary to guard against such heating by the use of cut-outs or thermo-positive resistance-devices. In the present construction, however, the heat communicated to the core 10 from the primary winding follows a continuous metallic conductive path, through the yoke-member 13, the plate 19 and the tie-rod 17, to the bottom'of the cas? iiig, and since this casing is also of metal, it a ords an effective radiator to dissipate the heat so conducted to it. Accordingly, it has been found unnecessary to use cut-outs or resistance-devices with the present coll, since it will sustain without injury a continuous iiow of current under the full E. M. F. employed in the normal intermittent operation of the coil.

The invention is not limited to the embodiment thereof hereinbefore described and illustrated in the accompanying drawings, 'but it may be embodied in various other forms within the scope of the following claims.

The invention claimed is:

1. An induction coil having, in combination, a straight iron core; windings on said core; an endless yoke-member surrouding said core and magnetically connecting the ends thereof, said yoke-member comprising iron-wire coiled continuously; and clips embracing said wire at each side of the portions adjacent the ends of said core.

2. An induction-coil having, in combination, a straight core of iron wires; windings on said core;and an endless iron yoke-member, structurally separate from the core, surrounding the core and magnetically connecting the ends thereof, with one end of the core in close metallic engagement with said member and the other end separated from said member by an air-gap.

3. An induction-coil having, in combination, a straight core; windings thereon; a yoke-member magnetically connectin the ends of said coreand a tie-rod passing on tudinally through the core and throu h the adjacent portions of said yoke-mem er to secure the parts together.

4. An induction-coil having, in combination, a straight core; windings thereon; a yoke-member magneticall connecting the ends of said core; a casing inclosing the parts before recited; and a tie-rod passing through the core and the adjacent parts of said yokemember and secured to said casing.

5. An induction coil having, in combination, a straight core of iron wires; windings thereon; an endless yoke-member magnetically connecting the ends of said core and formed of iron wire coiled continuously; and a tie-rod passing through said core longitudinally and through the adjacent parts of said yoke-member.

6. An induction coil having, in combination, a core, windings thereon; a yoke-member formed of substantially parallel strands of iron wire; and means, for securing said core and said yoke-member together, passin between adjacent strands of the wire whic constitutes the latter without severance of said strands.

7. An induction coil having, in combination, a core, windings thereon; a yoke-member formed of substantially parallel strands of iron Wire; means, for securing said core and said yoke-member together, passin between adjacent strands of the wire w ich constitutes the latter without severance of said strands; and ineans embracing the yokemember on either side of the securing-means and holding the strands of wire in close engagement with each other.

8. An induction-coil having, in combination, a straight core of iron wires; windings thereon; an endless yoke-member surrounding said core and magnetically connecting the ends thereof, said member being formed of iron wire wound continuously; and a tie-rod extending longitudinally through the core and thrust through the core-member between adjacent strands of the iron wire thereof.

9. An induction coil having, in combination, a straight iron core' an endless yoke member connecting the en s of the core and formed of iron wire wound continuously; windings on the core; a metal casing inclosing said core, yoke-member and windings; and means for pressing the yoke-member toward a wall of the casing to maintain a heatconductive connection between these parts.

10. An induction-coil having, in combination, a core; windings thereon; a casing provided with a removable metal head; a terminal-block seated on said head; and a tie-rod 4passing through said terminal-block, head and core to secure all of these parts in place.

11. An induction coil with a casing having a removable metal head provided with two adjacent o enings; in combination with a terminal-b ook seated on the outer surface of said head and provided with portions dependin throu h said openin and with conductive inserts ocated in sai de ending portions and accessible from bot inner and outer surfaces of the terminal-block.

EARLE P. LEE. THOMAS L. LEE.

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