US1344723A - Magneto - Google Patents

Description

-W. E. SCHWARZMANN.

MAGNETO.

APPLICATION HLED on. 12. ma.

1 ,344,723, Patenwd June 29, 1920.

of the ma UNITED STATES PATENT OFFICE.

WOLFGANG ERNEST SCHWARZMANN, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR, IBY MESNE ASSIGNMENTS, TO AMERICAN BOSCH MAGNETO COBIORATION, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

MAGNET).

Specification of Iietters ratent. Patented J une 29, 1920.

Application filed October 1 2, 1918. Serial No. 257,841.

To all wk mit may concern: or other type, having many cylinders, or

Be it known that I, Wows-mo E. rotating at high speed, or both, wherein the SCHWARZMANN, a citizen of the United power strokes occur at irregular intervals. States residing at 51 Bellclaire avenue, In accordance with my invention, I provide Long Meadow, Spririgfield, in the countypf a magneto having an unsymmetrical ma Hampden, State of assachusetts, have innetic circuit, that is one in which the trai ing'tips of the field and armature poles are disposed at irregular intervals around a circle, or a magneto havi the field and armature poles and the mem ers of the sleeve so constructed and arranged relatively to each otherthat upon rotation of the sleeve, the trailing tips of the sleeve members leave the trailing tips of the field and armature poles at the unequally spaced intervals corres ending to the irregular ignition desired. referably, I do this by providing unsymmetrical field poles, or'unsymmetrical arma ture poles, or both, the members of the sleeve being coordinated with those poles to break away therefrom at the irregular intervals, and thereby alter the magnetic flux in the generating winding. By altering the electrical circuit of the generating winding at substantially those irregular intervals, as, for instance, by a mechanical interrupter on an electro magnetic sparkplug, ignition volta s are generated at those intervals; and y arranging the distributer to then connect the generating winding to the suc cessive spark-plugs, ignition sparks are produced in the engine cylinders at the firing periods desired.

In the accompanying drawings illustrat ing my invention in application, as an example, to a high tension magneto havinga bipolar field and armature and a sleeve for generating four ignition voltages per rotation for a 12-cylinder, -cycle engine with its cylinders on a 45 V,

Figure 1 represents a longitudinal cross section of one embodiment of my invention;

Fig. 2 is a transverse section of the magneto of Fig. 1;

Fig. 3 is a wiring diagram showing the mechanical interrupter and the distributer associated with the magneto;

Fi 4 to 7 are diagrams showing the position of the rotatable sleeve'at four successive ignition iper-iods; and

Fig. 8 represents a modified construction.

Referring particularly to Figs. 1 to 7 the vented certain new and useful Improvements in Magnet/us; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will eiiable others skilled in the art to-which it appertainsto makeand use the same.

[he present invention relates to magnetos of the sleeve type fori iting combustible mixtures in internal com ustion engines,the sleeve having members of magnetic material and being rotated in the air gap between the armature and field poles of the magneto to alter or reverse the flux flowing from the field magnet through the generating winding at the intervals of ignition.

Airplane engines are now made with 8 to 18 cylinders in V or fan arrangement with the two or three planes of cylinders spaced apart difl'erently than the usual angle, which, in the case of two planes, is 90 for 8 cylinders, 60 for 12 cylinders, or, in general, is equal to 360 or 720 divided by the number of cylinders. Other airplane engines have their cylinders arranged in one or two circular series. In some of such engines, the departure from the usual spacing necessitates ignition at irregular intervals, that is at unequal angles of rotation; for instance, an engine at present in use has 12 cylinders arranged in two planes on a 45 V, and requires ignition at 45,'75, 45, and so on, inasmuch as the explosions occur in the cylinders of the two planes alternately.

Furthermore, the lar e number of cylinders, or the high spec of rotation o the engine, or both, necessitate such excessively rapid sparkin that when a magneto is used it should pro uce more than the two sparks per rotation generated by an ordinary bipolar magneto, because the speed of rotation eto would otherwise be too high. The ob ect of my invention isto provide a magneto which meets the foregoing requirements, and is, therefore, intended especially for association with an internal combustion engine of the V, fan, circularr magnetic circuit of the magneto includes a stationary permanent magnet l with poles 2 and 3, and an armature core with oles 4 and 5 connected by the cross bar 6. e corresponding tips of the W" field poles, and also of the two armature poles, are the rammatically opposite. the armature poles eing disposed in the field interpolar spaces so that the trailing tips of one are substantially in radial line with the leading tips of the other. Furthermore, each field interpolar space. and thus each armature polar span, is substantially (57.5" in an ular extent, and each field polar span, and thus each armature intcrpolar space, is substantially 112.5. In general, these an ular extents are sub stantially tqlltll to the irregular intervals of firing of the engine multiplied by the ratio of the magneto speed to the engine crank shaft speed, or, in this case, to 45 times L}. and 75 times 12;. respectively.

The armature poles 4, 5 are abbreviated on opposite sides of the center line A.-.\ of the crossbar (5; aml the angular extents of the portions of those poles as well as of the field pole 2. 3. are dissimilar in adjacent quadrants with respect. t. that line, but similar in alternate quadrants.

The magnetic sleeve has two iron |nem hers S magnetically sepa'atcd fiom each other and held in position by the brass end plates 9. The members have a like span of about 72.5". and are arranged to simultaneously bridge the field interpolar spaces, and to later simultaneously leave the trailing tips of the armature poles.

The shafts Ill. 11 of the sleeve arc sup ported in ball bearings 12, 13 carried by the members-14. 15 which are secured to the base plate of the magneto and are therefore rigid with respect to the poles of the field magnet 1. The shafts 16 and 17 of the armature are mounted in ball bearings 18, 19 carried in enlarged recesses of the two shafts of the sleeve. The shaft 16 extends through and bcvond the hollow shaft ll) and carries a collar 20 fast with it and with a stationary member 21 to secure the armature against rotation. The sleeve is rotated in its bearings by the gear :22. which is of proper size to be driven from the crank shaft of the engine at the required speed ratio. As shown diagrammatically in Fig. 3. one terminal of the primary turns 23 of the generating winding is connected to one terminal of the secondar turns 2-l of the generating winding. and thence to the stationary insulated element an of the mechanical interrupter. The other terminal of the primary turns is "grounded. while the other terminal of the secondary turns is connected to the rotatable brush 26 of the distributer. which is driven by the gears 31 34, at the required speed of rotation. in thlsrcase at one-third the speed of the sleeve. he cam member of the me chanical interrupter is fast with the sleeve and has four cams 2T spaced apart 67.5", 112.5, (i7.5, and 112.5", to deflect the grounded movable element 28 of the me chanical interrupter and thereby interrupt the primary turns of the generating wind ing at the irregular intervals of ignition. At those intervals the distribnter brush 26 engages the sparkplug distributing contacts 29, which are correspondingly irregularly spaced to conduct the ignition currents from the generating winding to the insulated terminals of the spark-plugs 30 in the engine cylinders.

The position of the sleeve members at the four irregular intervals of ignition are illustrated (liagrammatically in Figs. 4- to T for the embodiment of the magneto shown in Figs. 1 to 3. In Fig. 4, the trailing tips of the members 8 of the sleeve are leaving the trailing tips of the field poles 2, 3. thereby reducing the magnetic flux flowing through the cross bar (5. and therefore in the generating winding mounted thereon. Shortly after that moment. the magnetic flux is established through the aimatnrc in the opposite direction. the finx thus being reversed in a small angle of rotation. .;\t (37.5 later in the rotation. the trailing tips of the sleeve members 5 leave the trailing tips of the armature poles l. 5. as shown in Fig. 5. the flux previously flowing through the armature being reduced. .\t about 4-0" after this moment, the magnetic llnx is established in the opposite direction through the armature and thus completes the re vcrsal of the flux therein, the leading tips of the sleeve members then being opposite the leading tips of the armature poles. At 1112.5 after the second point of ignition. or 180 after the first. the trailing tips of the sleeve members it again leave the trailing tips of the field poles 2. 3. as shown in Fig. (i; and at (37.5" later. or 180 from the second period of ignition. those lips leave the trailing tips of the armature polcs. as shown in Fig. T. At each of these ignition periods, \'i'/.., at 1. (37.5", 180 and 247.5" from the position of the sleeve shown in Fig. 4. the mechanical interrupter opens the circuit of the primary turns and the distributer brush engages the spark plug distributing contact to conduct the ignition current produced in the generating winding to the spark plug connected thereto.

In the modification in Fig. 8, the field poles 31 are symmetrical. instead of unsymmetrical, and each .sleeve member 32 base. span. of about 90, which is slightly greater than the field 'interpolarspace. The elfect of these changes is that, whereas the reversal of the magnetic flux in the armature when the sleeve members bridge the field interpohir spaces occurs'in substantially the same angleof rotation as before the renet having poles versal when the sleeve members bridge the armature interpolar spaces occurs more rapidly than before. In both modifications, but particularly in the latter one, the successive ignition voltages are sufliciently alike for practical purposes throughout the ordinary range of speed of the en ine with wluch these magnetos are inten ed to be associated.

It is to be understood, of course, that various other forms of field and armature poles may be used, and that the sleeve members may also have other forms in coordination with the poles. Such modifications are obviously within my invention which embodies an unsymmetrical magnetic circuit, or one in which the trailin tips of the sleeve members leave the trai ing ti 5 of the field and armature poles to give the irregular intervals of ignition required by an engine of the kind hereinbefore referred to; the mechanical interrupter altering the circuit of the generating winding at said intervals.

Having thus described my invention, what' I claim is:-

1. In a magneto for producing i currents at irregular intervals, a el an armature having poles, a sleeve rotatable in the air ap between the field and armature has and avin magnetic members magneticall separate from each other, the poles and't sleeve members bein so constructed and arranged that the traili 0 tips of the sleeve leave the trailing tips 0 the poles at irregular intervals, a generatin winding, and means forraltermg the circuit of the generating winding at substantially said intervals.

2. In a magneto for producing currents at irregular intervals, an unsym metrical magnetic circuit, a generating magwinding, a magnetic sleeve rotatable in the air gap of said magneticcircuit' to alter the magnetic flux in the 'enerating winding at the irregular interva s determined by the unsymmetrical magnetic circuit, and means for altering the electrical circuit of the generating winding at said intervals.

3. In a magneto for producing ignition currents at irregular intervals, antunsg m eld metrical magnetic circuit including a magnet having poles and an armature having poles, a generating windin on the armature, a magnetic sleeve rotatab e in the air gap between the field and armature poles to alter the magnetic flux in the eneratin winding at the irregular intervals etermine by the unsymmetrical magnetic circuit, and 'means for altering the electrical circuit of the generating winding at said intervals.

4. In a magneto for producing ignition currents at irregular intervals, an uns mnu-tricul magnetic circuit including a eld magnet having poles and an armature havthe generating 5. In a magneto for producing ignition,

mined b ition in the ignition ing unsymmetrical poles, a generating wind: ing, a magnetic sleeve rotatable in the air between the field and armature poles, to alter the magnetic flux in the generating windin at the irregular'intervals determined the unsymmetricahmagnetic circuit, an meansgforaltering the circuit of windingat said intervals.

currents at irre metrical magnetic circuit including a magnet'having unsymmetrical poles and an armature having oles, a generating winding, a" magnetic s eeve rotatable in the air gap between the field and armature poles to alter the magnetic flux in the generating winding at the irregular intervals deterthe unsymmetrical magnetic cirmeans for altering the circuit of at said intervals.

lar intervals, an runs cuit, an the generating winding 6. In a'magneto for currents at irre lar intervals, an uns mmetrical magnetic unsymmetrical poles, a

generating winding, tatable in the air ga armature poles to a generating windin interva 5 determined by t e unsymmetrical magnetic circuit, and means for altering the circuit of the generating winding at said intervals.

7. In a magneto for producin ignition currents at irregular intervals, a field magnet having poles, an armature having poles and a connecting cross bar, the angu ar extent of the portions of the field poles and of the armature poles being dissimilar in adjacent uadrants-with respect to the cenher line 0? the cross bar, a magnetic sleeve rotatable in the air gap between the field and armature poles, and means f or alter ing the circuit of the generating winding at irregular intervals.

8. In a magneto for producin ignition currents at irregular intervals, a fie d magnet having poles, an armature having poles and a connectm cross bar, a generating winding, the angu ar-extent of the portions of the field poles and of the armature poles being dissimilar in adjacent quadrants with respect to the center line of the cross bar, and being similar in alternate uadrants, a magnetic sleeve rotatable in t e air gap between the field and armature oles, and means for altering the circuit 0 the generating winding at recurring irregular intervals.

' 9. In a magneto for producing ignition currents at irregular intervals, :1 field magnet having poles, an armature having poles abbreviated on opposite sides of the connecting cross bar therefor, a magnetic sleeve r0- tatable in the air gap between the armature tor the -magnetic flux at the irregular producing ignition between the field and eld circuit oom rising a eld magnet having unsymmetrica poles and an and field poles, a generatingwinding, and means for altering the circuit of the generating winding; t irregular intervals.

10. In a m new for producin ignition currents at irr ular intervals, a 'eld magnot having poles, an armature having poles with interpolar' spaces different from the field interpolar spaces, a magnetic sleeve rotatable in the air gap between the field and armature 'poles, a generatin 1 winding, and means for altering the circuit of the generating winding at irregular intervals substantially ual to the interpolar spaces of thefield an armature. h

11. In a magneto for producing ignition currentsat irregular intervals, a field magnet having unsymmetrical poles, an armaliiire havingains ymmetrical oles with their tips substantial] in radial lme with respective tips of the eld poles. a magnetic sleeve rotatable in the air gap between the armature and fie poles, a generating windin and means, or altering the circuit of the generating winding at irregular intervals.

12. In a magneto for producing ignition currents at irregular intervals. an unsymmetrical magnetic circuit including a field magnet having poles and an armature having poles, a magnetic sleeve rotatable in the air 'gap between the field and armature poles and comprising magnetically -separated magnetic members each having a span substantially equal to the field interpola r space, a generating winding, and means for altering the circuit of the generating winding at the irregular intervals determined by the unsymmetrical magnetic circuit.

13. In a magiieto for producing ignition currents at irregular intervals, a field magnet having unsymmetrical poles, an armature having unsymmetrical poles. a magnetic sleeve rotatable in the air gap between the field and armature poles, a generating winding, and means for altering the circuit of the generating winding at irregular intervals, each of the field inter-polar spaces being substantially equal to one of the irregular intervals and each of thc :llllHlLHl'L' lll terpolar spaces being substantially equal to the ad'accnt one of lhc irrcgular inlcrvals.

14. n a magncto for producing ignition currents at irregular intervals. a licld mag not having poles diilc rcnl in span from its intcrpolar space. an armature having poles different in span from its intcrpolar space, a magnetic sleeve rotatable in the air gap between the field and armature poles. a generating winding. and means for altering the circuit of the generating winding at the irregular intervals determined by the ficld and armature interpolar spaces.

1:). In a magneto for producing ignition currents at irregular intervals. a bipolar field magnet having intcrpolar spaces each less than 90. a bipolar armature having interpolar spaces each grcatcr than 5H). a mag netic sleeve rotatable in the air gap be tween the field and armature polcs and hav' ing two magnetic members each of a span substantially equal to the field inlcrpolar space. a generating winding. and means for alterv g the circuit of the generating wind ing at the irregular intervals determined b v the interpolar spaces of the field and aruuc ture.

10. In a magneto for producing ignition currents at irregular intervals. an llll1-. \llimetrical magnetic circuit. a generating winding having primary and secondary turns, a magnetic slecvc rotatablc in an air gap of said magnetic circuit. a mechanical interrupter for opening the clcclriczil circuit of the primary turns at thc irregular iiitervals determined l1 v tbc llllt \'liilill'll'il'ill magnetic circuit. and a distributcr having a brush connected to one terminal of the secondar v turns and also having stationary sparlcplug distributing contacts arranged at angular intervals coricsponding with the irregular intervals of operation of the incclzanical interrupter.

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