US1578637A - Magneto - Google Patents

Description

March 30 1926. 1,578,637

P.'B ROWN MAGNETO Filed Feb. 25, 1924 4 SheetS-She8t 2 INVENTOR 7? ATTORNEYS March 30,1926. 1,578,637

' P. BROWN MAGNETO Filed Feb. 25, 1924 4 Sheets Sheet Z5 ATTORNEYS March 30 Q 1926. 1,578,637

P. BROWN MAGNETO Filed Feb. 25, 924 4 Sheets-Sheet 4 INVENTOR BYW ATTORNEYS Patented Mar. 30, 1926.

hair so are rarer PHELPSBROWN, 05F :SERIMGFIELD, I'JIASSACEUSETTSE' MAGNETQ- Applicationifiled February25, 1924. SeriaLNo. 695,096.,

To all whom it may concern:

Be 1t known that I, PHELPS BROWN, a cit1 Zen of the United States, reslding at Sprlngfield, in the county of Hampden and State of Massachusetts have invented new and useful Improvements in liiagnetos, of which while desirable from the point 01" view ot" low reluctance of the magnetic circuit, neces-' saril tends to create noise andwhile enough has been done in the past to prevent excessive noise of contact in magnetos intended for relatively low speed operation, the prior developments are not sinlicient to overcome the noise of contact when the armature is operated at relatively high speeds, such as are necessary when the mag netos are to be used in connection withlinulticylinder engines, such as are used in tractors, trucks, automobiles, aeroplanes and the like. The driving of the armature aw y from its poles at speeds independent of eng ne speeds is important in magnetos operated by relatively slow speed engines and it is important in any event for starting purposes. In magnetos operated by high speed engines, however, the armature can be operated at speeds dependent on engine speed and armature speeds equal to, or greater, than'thespeeds obtained by spring drive of the armature can be obtained.

The present invention is directed to the provision oLt a magneto intended for operation with relatively high speed "engines and the invention seeks to provide a magneto which is suitable for 'multi-cylinder engines, such as the engines used on tractors, motor trucks, automobiles, aeroplanes and so forth.

In adapting a' magneto, oi the general class described, for the new and extended field of service above Serena, one ofthe characteristic features ot the magneto, hitherto accepted almost as landmarlq'has had to be dispensed with, at leastat'certain desirable on account of the ensuing noise.

stages ot the 'magneto operation. This tea; ture it that of physical contact of the'armature with its poles. 'Ihe'preventi'on of "such. contact at high armature speeds is obviously It is also desirable and-practicaily essential to reducevibration and to prevent excessive Wear on the parts which would otherwise occur due totlie high speed "operation of the armature. At the same time, contact of the armature with its poles may, undercertain conditions, particularly at cranking speeds, be desirable.

It is therefore an object of this ingention to provide, in 1 a magneto of the, general class described, means Whereby'the arma ture may be prevented from contaetingwitlr its poles, as and whendesir'edQ It is also an object of the. iHVQIlUOIlltO provide means whereby the minimumair gap between'the armature and its poles may be varied, as and when desired, and preferably, althoughf'not necessarily, varied -tr om a predetermined maximum gap to zero. I

Another object is to provide means con trolled by variation of the minimum air gap for varying the timingxof the spark "generated. f

Anothercb'i'ect :ot the invention is to pro vide, ina magneto of the general class'described, means "whereby the electricalout out may be'varied and controlled,- as dsiredf; Anotherobject of the invention is topro vide aspecifically improved armature :actu

ating mechanism, characterized in that the armature isoperated at speedsproportionate to engine speeds" and withoutthe use of elastic driving means, such as springs.

Another object of "the invention is toprovicle an armature actuating mechanism,:consistingot' a quick throw cam driven by'the engine, and connections therefromto the armature for moving the latter by anwin+ elastic transmission of torce,such connections including a lever, the fulcrum otwhich is adjustable to control the degreeot approach otthe armature toward-its poles. Another object of theinvention is toprovide improvedfmeans for controlling the breaker points which open and closethe choke winding of "the magneto.

More particularly; itis an object-of the invention to'provicie means independent ot the armature for controlling the breaker points to the extent of holding themopen vention.

for the purpose of enabling the flux to build up rapidly in the magnetic circuit. Ordinarily, the breaker points are connected for operation from the armature and close when the armature closely approaches the poles, thereby forcing the flux to build up against a short circuited choke winding which retards the action. While the latter arrangement is desirable if sur'licient time intervals are available, as in inagnetos operating at relatively low armature speeds, it is not commercially satisfactory in the present case where high speed operation of the armature is desired and where a rapid building up of flux is consequently necessary.

Other objects and advantages will appear in the following description and in the illustrative embodiment of the invention in the accompanying drawings, in which Fig. 1 is a side elevation view of a magneto embodying the invention, certain parts being broken away to reveal interior construction;

Fig. 2'is a front elevational view thereof with the front casing removed to show cer tain magneto parts;

Fig. 3 is an elevational view taken from the right hand side of Fig. 2;

Fig. 4: is a diagrammatical view illustrative of the magnetic and electrical circuits of the magneto; and

Figs. 5, 6, 7 and 8 are fragmentary views, taken similarly to Fig. 1 and illustrating successive steps in the operation of the magneto.

Referring to these drawings :The magneto include a suitable source of magnetic flux, herein shown as a series of bar magnets 10, to the poles of which are suitably and magnetically connected two laterally spaced and depending cores 11, preferably made up of laminations in the usual manner. On each core 11 is a suitable generating coil 12 and a choking coil 13, the coils 12 being suitably connected, as in series as indicated in Fig. 4:, and the coils 13 being similarly connected, as there indicated. An armature 14, preferably made up of la1ninations in the usual manner, is mounted in any suitable manner for movement toward and away from the lower end of at least one of the cores, and usually away from the lower ends of-both of the cores 11. These core ends constitute magnetic poles and the object of the armature movement, however effected, is to vary the reluctance of the magnetic circuit, whatever its particular nature. As shown, such circuit comprises the source 10, cores 11, armature 1 1, and the air gaps between the latter and its poles. The precise arrangement of the magnetic circuit and the means for effecting variations therein are not essential features of the present in- The terminals of the connected coils 12,

which together form the generating winding, are connected to the ignition system in any usual and desired manner. Usually one terminal of the winding is grounded, as indicated at 15, and the other terminal is connected, as by a wire 16, to a spark plug 8, or the wire '16 may, when the magneto is used in connection with mnlti-cylinder engines, lead to a distributer. The choking winding, afforded by the connected coils 13, is arranged in an electrical circuit which can be opened and closed by two cooperating breaker points 17 and 18, one of which, as 18, is connected metallically, as will appear, to the frame of the machine and is thus grounded. :One terminal of the choking winding is likewise grounded, as indicated at 19, and the other terminal is connected by a wire 20 to a breaker point 17. A condenser 21 is bridged across the breaker points in the usual manner, being connected by wires 22 and 23 to point 17 and ground 19, respectively.

The breaker point 17, as shown in Fig. 1, is stationarily, but adjustably, fixed in arm insulated from the upper end of a tube 24, which in turn is suitably fixed in a metallic but non-magnetic part 25 of the magneto frame. The breaker point 18 is mounted in the upper end of a cylinder 26 which is slidable in'tube 24: and metallically connected therewith and thus grounded to the magneto frame. Fixed to cylinder 26 is a stem 27 which extends out of the open lower end of tube 24 and passes loosely through an abutment 28, fixed on armature 141, and is provided below such abutment, with an adjustable abutment 29 for engagement with. the latter. The stem 27 passes freely through felt washers 3O superposed on abutment 28 and provided for lubricating purposes, and a spring 31 acts between the latter and the base of cylinder 26, tending to hold the abutments 28 and 29 in contact and, under the conditions illustrated in Fig. 1, tending to hold the breaker points in close contact.

The magneto parts, above described, are all suitably supported from a frame which is secured, as by bolts 32, to the engine, or a part of the frame thereof,'herein exemplified by a bracket A complete disclosure of the construction of the magneto proper will be found in the copending application of Phelps Brown and Terrence G. Louis, filed July 18, 1323, under Serial No. 652,356. A detailed description of the magneto construction is not, however, essential for an understanding of the present invention.

The magneto, as thus far described, will serve as an illustrative example of one suitable type of magneto in which the invention may be embodied. Many other magnetos of similar character are adaptable to the present invention and the foregoing description is intended to set forth merely a general type andthe details of the constructionand arrangment of parts are not important to, or essential parts of, the present invention.

Thearmature 14; may be: mounted for movement toward and away fromthe end of one or both'of the cores 11 in anysuitable manner, as above set forth. As shown, the armature is slidable in austraight line on a guide pin which is fixed to the frame member 25 and extends downwardly therefrom, passing freely through the centralportionof armature 1%.. Centrally fixed tothe latter and depending therefrom is a fork 36, the dependingwarms of which are bridged and interconnected by'av pin 37. The latter is received in the forked outer extremity of an arm, 38, integral with which isa depending arrn 39,the'two arms forming a bell cranlrlever which is pivotaliy mounted at the junction ofithe arms. on a stud 4:0; The arm 39 constitutesia follower for a cam e1, fixed. on a shaftJiQ, suitably drivenv-at the desired speed ratio from the engine crankshaft. A spring 13, mounted in a recess 44 provided in bracket 33, acts on the'lower end. of an arm 39 and tends to hold it in engagementwith: cam e1.

The armature operating means isvdifi'eiw enti ated fromthatiordinarily employed in magnetos of this generalatype in that the armature is at-all times'opera-ted by an. inelastic t 'ansmissionfrom the driving shaft.

The usual drive spring, which .is stressed during the revolution of suchshaft'and subsequent-ly released to move the armature at.

a speed independent of engine speed, is entirely dispensed with for the present Imagnetoisintended for use with engines wherein armature speeds, equalto or in excess oi those obtainable by drive springs, can be obtained by the operating means herein:

disclosed.

he stud is fixed to a collar 25 in eccentric relation therewith and projects out- Wardly therefrom in the fashion of a crank pin. tion therewith, and thus eccentrically with relation to stud. 45,: is a shaft 4:6 which is mounted to turn in. a bearing lbracket 33. Integral with bracket 33 and concentrically disposed. with relation to shaft 46 is a sector 48, the curved edge-4 9 of which is notched, as shown in Fig. Fixed to shaft 4:6 is-an arm 50, the hub of" which functions as a collarand cooperates with; collar and the endufacesxo'f bearing.

4:? to limit the end play of shaftttitherein. Arm 50 isadaptedto swing adjacent sector 4-8 and is provided with a cylinderical portion 51 which overliesthe curved edgedi). Mounted in portion 51 is a'spring pressed detent 52 which is constantly urged toward the edge a9 and is adapted to engage in any ot the notches therein to hold shaft i6 in various positionsof angular adjustment in Fixed to collar L5 in concentric 1Blz.-

( formed on:

bearing 27. Byturningarm 50, the stud- 40" may be raised :and lowered and 'alsomoved laterally with respect-to the center of shaft 46 and consequently the pivotalv axis of the armature actuating bell crank lever may be varied. The important effect of this variae:

tion of the location of the pivotal. axis is tocontrol theadegree to which the armature l-ii approaches theends of cores 11-orrthe-extent .of theininimum air gap therebetweeir. The stud lO maybe so-positioned that armature 14: can come into physicalucontact with cores 11 or it may be 'so positioned, as illustrated; to prevent .suchcontact and so limit the degree of approach of the-armature to cores 11 that a minimum air. gap: such 4r,

(Fig. 1), is left therebetween; Alsothe extent of this air gap 00 may be varied within limits, as desired.

The results described follow for two areasons. First, if the stroke'of'the armature 14 be regardedas constant, then thelocationof this stroke with respect to fixed v parts of the magneto is-varied by the vertical movements ofadjustments ofstud; 40. Second, thevertical movementsof'stud 10,1 asa matter of fact, cause camel toengage'.

arm 39 along. lines of'contact whicharei at.

difierent distances from the center of-stud' .420, whereby the efie ctive length offarln 39 may be varied to vary the extent of stroke 53 is a suitable cam follower 58, herein' shown as a lever pivoted to bracket 33 at 59 and underlying cam 53, beingyieldingly held. in; contact-with the latter by" a (spring:

59. The-free endjof lever 58 is be'ntatrigh'tangles, as shown at 60 in Fig.12, tolievertically beneath the end of thwbreakerrpoint. stem 27. A link: 61, one-end oiiiwhiclnis inturned and engaged in a :hole in the end 60 of lever'58', extends upwardly'and enters freely into the bottom of sleeve 62. The latter is fixed, preferably in an adjustable manner, .as shown in Fig. 1, .to-the lower end of stem'27 and-below the latter: has a cylindrical bore 63 in whiclra head'6 l, fixedon link 61,.is freely slidable'; The arrangement is such that stem '27 and-.theattached sleeve 62 may move downwardl independently of link: 61, whereby the breaker points 17 and l3'may beseparated in. the usualway by the engagement of abutment 28 on the armature with abut; nient 29 on stem 27. The arrangement is also such that lever 58 maybe depressed by cam 53, thus drawing link 61 downwardly until head 64 engages and moves sleeve 62 and thus moves the breaker point 18. The various parts in the breaker point operating mechanism bein adjustable, they may be adjusted and timed so that either means can operate the breaker points. l'ly preference, however, the latter are opened in the usual manner by the movement of the armature and are prevented from again closing by the operation of cam 53 until the armature has reached the upper limit of its travel. The prevention of the closing of the breaker points is important in that the flux is permitted to build up rapidly in the magnetic circuit, since the choking coils 13 are prevented from exercising their retarding influence which would occur if the breaker points were in contact. The breaker points are allowed to close after the armature has dwelled in its upper position for a suflicient interval to permit the flux to build up in the magnetic circuit.

The armature driving means, as above disclosed, includes a cam and desirably this cam is 'a quick throw cam of the general type illustrated. The particular contour of cam 41, and the manner in which it coacts with follower 39, is important because of the resulting effects obtained in the operation of the armature and the breaker point mechanism. The greater portionof cam 41 is concentric with shaft 42 and the concern tric portions are made up of a relatively large low dwell portion 65 and a relatively small high dwell portion 66. The portions 65 and 66 are connected by rise and fall portions 67 and 68, respectively,-these portions being straight and arranged in outwardly converging relation. In the'counterclockwise rotation of cam 41 (as viewed in Fig. 1) the portion 6'? will eventually move into parallel and contiguous relation with the follower 39. This occurs after cam 41 has moved through the angle a and the relative positions of the parts which then obtain is illustrated in Fig. 5. Thereafter, continued movement of cam 41 moves the follower and the armature 14 but the movement of the latter, at least in its initial stages, is relatively slow as the contiguous faces 39 and 67 begin to move out of parallelism. The relatively slow initial movement is followed by a progressively and rapidly increasing movement which reaches its maximum as the parts move into the relative positions shown in Fig. 6. lhe condition there illustrated is that which ob tains at'the end of the mov ment of fol lower 89. During the movement of cam 41 through the relatively small angle 5, the armature 14 is moved away from poles ll and to the lower limit of its downward stroke. The action is therefore not only very quick but the armature is started in motion relatively gradually and 'itn. as

little shock as possible. The relatively gradual initial action is especially important when the condition of physical contact exists between the armature and its cores. The powerful magnetic hold then existing between these elements is broken in a highly eli ective manner and in one calculated to produce the least wear and tear on the parts at high speed. Having thus started the armature in motion, quick acceleration is then desired to get the armature moving at high speed and when the armature has at tained the points are separated and moreover, are separated at high speed to cause a. ouick break and one which is least apt to have detrimental eifects on the breaker points. Note that the breaker points do not separate during the initial movement of the arma ture. At this stage, the spring tension is diminished although not entirely relaxed but separation of the points does not occur until the abutments 28 and 29 engage and these engage only after the armature has acquired considerable speed. The breaker points being closed, the choke winding tends to prevent a rapid change of flux in the magnetic circuit and the breaker points may be likened to a valve for, as soon as they are opened, the flux is released and, the armature having moved a considerable part of its stroke away from the poles and established a substantial air gap therebetween and acquired a high rate of speed, a sharp change efflux in the magnetic circuit ensues, resulting in the production of a substantial spark. I

The cam 41, as it moves through the angle 0, has no elfect in moving the armature and the latter dwells in its lower position. As cam 41 continues to move, however, the armature is moved toward its poles again and in a reverse manner to that already described. That is, it moves rapidly at first and progressively decreases in speed as it approaches the poles. After the cam 41 has moved through the angle (Z, the armature has then approached as closely to poles 11 as the adjustment of the stud 4O permits and dwells in this position during the travel of cam 44 through angles 6 and a. Itis to be noted, however, that the breaker points are prevented'from closing during the upward flight of armature 14 because at the time when cam 41 moved the armature into the lowermost position the portion 56 of cam 53 came into action to lower the lever 58. Thereafter, the armature moves toward poles 11, the head 64 restrains the upward movement of breaker point 18, which would otherwise be permitted by the armature. Consequently, the breaker points are allowed to engage only after cam 523 permits and this is permitted only after the armature has attained the uppermost position and has re requisite speed, the breaker:

mained in that position-long enougl'r to build up the desired-amount of flux in the mag netic circuit, at which time the lever 58 quic :ly releases the breaker points and allowsthem quickly to en The general operation of the magneto having been explained, it ren'iains to consider the special features relating to the means whereby the minimum air gap be tween the armature and its poles may be varied; As above set forth, the arrangement is such that the armature ma contact with its poles, thus affording a minin'ium reluctance for the magnetic circuit by the entire elimination 0t air gaps, the reluctance of which, as is Well known, is ex,- ceedingly high. The provision for contact between the armature and poles is desirable for starting because it is assumed that relatively low armature speeds will then be available.

After starting, the lever 50 is turned to varythe' position of stud so that contact of the armature and poles is eliminated. By so'doing, the-noise and the Wear and tear on parts incident to such contact is eliminated and the electrical output is governed so thatit suiiicient for low speeds it Will i not be excessive on high speeds. The elimination of contact is a practical necessity in a magneto of this type intended for high speed operation for by preventing contact of armature and poles, substantially all the noise of operation is eliminated and the magneto opera-tes very quietly and is sutlicientl-y noiseless so that its use on an automobile is entirely unobjectionable from this point of view. There are no parts which are subjectedto heavy blows at high speed or e:\: ceptionally rapid Wear so that the life of the magneto can be at least as great as any 01 the magnetos ordinarily used on automobiles. VJhile the eli-minataion of noise entails the existence of air gaps between the armature and poles, higher armature speeds are available when used in the described n'ianner in connection With automobile engines, or other multicylinder types than in single cylinder stationary engines, with which this type of magneto has been associ-' ated in the past. Armature speeds equal to,

)r greater, thanthose obtained by spring drive may be obtained and a greater armature speed can be chosen to compensate tor the necessary air gapslilagnets with higher flux values may oe chosen for the magnetic source to compensate for the presence of the air gaps. In fact, the magnetic flux and armature speeds may very easily be made suchthat it is necessary during normal high speed operation to create the air gap betiveen'the armature and its poles in order to prevent the generation of an excessive elect-remotes force which would puncture the windings and otherwise work injury in.

the electrical circuits. The arrangement, however, is such that the minimum air gap may be varied, as desired, to secure the desired results. On some installations the minimum air gap may be as small as it can be made Without actual contact occurring. On others, minimum ai-r gaps of greater degree'may be required and the adjustments described allow one to control and govern the electrical output of the magneto as desired.

In connect-ion With the means for varying the minimum air gap between the armature and its poles and in addition to the important resultant advantage of controlling the electrical output of the magneto as required, thereis another important feature which should be noted. The arrangement is such that the operator cannot get aback kick by cranking the engine even if the spark should be advanced. This result follows from the fact that anadvance in the timing of thejspark simultaneously effects the creation of an air gap and the creation of an air gap so increases the reluctance of the magnetic circuit that it is impossible to get a sufiicient spark at cranking speeds under these conditions. 7

While the elimination of contact of the armature with its poles is important and essential to the practical and commercially satisfactory operation of a magneto, oft-he general class described, at high speeds, there is another important factor Which -con tributes substantially to the successful operation of the magneto at high speed. This factor is the means for preventing the breaker points from closing on the upstroke of the armature. Nhile the flux can be built up in the magnetic circuit With the choking WlIICllIIf short circuited, the action is necessarily slow as the function of the choking Winding is to retard changes of flux in the magnetic circuit. In low speed magnetos, suflicient time may be afforded in which to build up the flux against the short circuited choking Winding and thus decrease the noise due to the magnetic attraction on the armature but in the present case the available time interval is very short and it is essential to eliminate every retarding influence. Consequently, the breaker points are purposely held open to expedite the building up of the flux in the magnetic circuit and the elimination of the noise has been. otherwise provided for.

It is also to be noted that the timing ot the spark is determined by the time of opening of the breaker points or by the time of engagement out abutments 28 and 29. This time may be varied by adjustment of the abutment 29 and obviously it may equally Well be varied by moving the abutment 28 instead. The adjustment of stud 40 by lever does, in. it? t also vary the timing toward or away from abutment 29.

and does so by adjusting the abutment 23 The time of flight of the arn'iatures may occur substantially at the same time in each revolution of cam 41 but the time of spark may occur earlier or later according to the distance existing between abntments 2S and 29, when the armature is in its uppermost position. When the armature is in contact with its poles, the spark occurs later in the armature flight and thus later in the revolution of shaft 42 than it does when the armatnr is positioned as shown in Fig. l. Consequently, when the lever 50 is manipulated to cause the armature to contact with its poles, for starting purposes, the spark is automatically retarded, as it should be, and independently of the operator, as is desirable. As lever 50 is moved to prevent contactof armature and poles or to running position, the spark is at the same time automatically advanced.

I believe myself to be the first to provide a magneto of the general class described with operating mechanism whereby the degree of approach of the armature to its poles may be varied as desired and where the armature can be made to contact wit-h its poles or not, according to the condition desired. I also believe myself to be the first to provide, in connection with breaker point mechanism. controlled from the armature movement, a supplementary controlling means independent of the armature for the general purposes set forth. Accordingly, I desire to claim my invention in the broadest possible legal manner.

IV hat I claim is 1. In a magneto, of the type wherein a reciprocating armature is movable toward and away from a stationary magnetic pole to vary the reluctance of a magnetic circuit, means for varying the reciprocating movement of said armature to vary the degree to which the armature approaches to said pole.

2. In a magneto, of the type-wherein an armature is movable toward and away from a magnetic pole, controlling means operable on the armature to enable it to contact with said pole or be held from contact therewith as desired.

In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole, means for controlling the movement of the armature to enable the minimum air gap between the armature and said pole to be varied.

l. In a magneto, of the type wherein an armature is reciprocable in a straight line toward and away from a stationary magnetic pole, means for varying the minimum air gap between the armature and said pole, and reducii'ig it to Zero when desired.

In a magneto, of the type wherein an armature is movable into and out of contact with a ma netic pole, means acting on the armature to prevent it from being moved into contact with said pole when desired.

6. In a magneto, of the type wherein an armature is movable into and out of contact with a magnetic pole, means acting on the armature for preventing such contact when desired without interfering with the freedom of movement of the armature.

7. In a magneto, of the type wherein an armature is movable toward and away from stationary magnetic poles, an operating shaft and connections therefrom to said armature for moving the latter from the former by an inelastic transmission of force therefrom at all times, and means for controlling the movement of the armature to thereby vary the minimum air gap between the armature and poles.

8. In a magneto, of the type wherein an armature is movable into and out of contact with stationary magnetic poles, an operating shaft and connections therefrom to said armature for moving the latter from the former by an inelastic transmission of force therefrom at all times, and adjustable means acting on the armature without interfering with its freedom of movement for preventing the armature from contacting with said poles.

9. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole, means for reciprocating the armature, and means for varying the loca tion of the reciprocating movement with respect to said pole.

10. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole, means for reciprocating the armature, and means for varying the stroke of said movement to vary the degree to which it approaches said pole at the end of one stroke of its movement.

11. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole, means for varying the de gree to which the armature approaches said pole, and means operable from the first named means for varying the timing of the spark.

12. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole, means tor varying the minimum air gap between the armature and aid pole, and means for advancing or re tarding the spark generated accordingly as the minimum air gap is increased or diminished, respectively.

13. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole, means for controlling the degree to which the armature approaches said pole and capable of allowing the armature to contact'therewith, and means con ill) lid

lfiii tively ;movablebreaker points, an abutment on the armature, an' abutment carried by the movable breaker point adapted to be engaged by the first named abutment to separate said points, meansyieldingly holding said points 111 contactarid the second named. abutment stationary with respect to saicktrame,means for operating the armature, and. means for adjusting the position of the latter with respect to said pole to vary the spacing between said breaker points and the timing of the generated sparks.

15. In a magneto, of the type wherein an armature is movable toward and away from amagnetic pole to vary the flux in the magnetic circuit a frame stationary with respect to said pole, cooperating and relatively movable breakerpoints, an abutment carried by the movable breaker point, a second abutment, means for moving the latter from an initial position to engage the first named abutment and separate the breaker points, and means for varying the initial position of the second abutment.

16. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole to vary the flux in the magnetic circuit, a frame stationary with respect to said pole, cooperating and relatively movable breaker points, an abutment carried by the movable breaker point a second abutment, means for moving the latter from an initial position to engage the first named abutment and separate the breaker points, and means operable during the operation of the armature and said mechanism to vary the initial position of the second abutment.

17. In a ma neto of the t )e wherein an from an initial posi tion in close proximity to magnetic poles to a second position remote from said poles to generate a spark and immediately returns to said initial position wherein it dwells until subsequently moved away to generate another spark. a choking winding associated with said poles and arranged in an electrical circuit which can be opened and closed, cooperating and relatively movable breaker points for controlling the opening and closing of said circuit, means adapted to hold said breaker points in contact when the armature occupies its initial and dwell position, means operable by n'ioven'ient ot the armature away from its poles tor separating said points after it has moved away from the initial position and before it reaches the second position, and means for preventarmature IllOVGS away ing or saidcircuit, means ing the breaker points iron'rcli-ising during the return movementof the arnniture and until it has come to rest in'saidfldwell position.

18. In ihllligllGtO, or the type wherein an :e moves agvay from an initial position in close pronimity'to magnetic poles to a'secondposition remotefrom said poles to generatea spark and immediately returns to said initial position -wherein it dwells until subsequently moved away to generate another spark, a choking winding associated 'with said poles and arranged in an elecandclosed,

trical circuit which. can be opened cooperating and relatively movable breaker points tor controlling the opening and clos- 7 adapted to "hold said breaker points in contact when the armature occupies its initial and dwell position, means operable by movement of the armature away tromits poles for separating said points atter it has moved away from the initial position and before it reaches the second position, and means to hold the breaker points open during the return stroke oi"- the armature and for releasing them for closure under the first named means after the armature has come to rest and is dwelling in said initial posit-ion.

19. In a magneto, of the type wherein an armature is moved toward and away from a magnetic pole, breaker point mechanism including a movable breaker point, a drive shaft from which said armature is actuated, means on the armature for moving said point in one direction and means operable from said shaft for controlling the move ment of said point in the other direction.

20. In a magneto, of the type wherein an armature is moved toward and away from a magnetic pole, breaker point mechanism including a movable breaker point, a drive shaft from which said armature is actuated, means controlled by movement of said armature for separating said points, and means controlled from said shaft for controlling the closing of said points.

21. 111 a magneto, ot the type wherein an armature is moved'toward and away from a magnetic pole, breaker point mechanism including a movable breaker point, yieldable means tending to hold said points in contact, an abutment carried by said movable point, an abutment on the arn'iature engageable with the first named abutment during its movement away from the pole to separate said points, and means for preventing said points from closing under the action of said yieldable means as the armature moves back toward said pole.

In a magneto, ot the type wherein an armature is moved toward and away from a magnetic pole, breaker point mechanism including a movable breaker point, yieldable means tending to hold said points in contact, an abutment carried by said movable point, an abutment on the armature engageable with the first named abutmentduring its movement away from the pole to separate said points, a second abutment carried by said movable point and means independent of the movement of said armature for engaging the last named abutment and holding said breaker points open after the first abutment on the movable point has been released by the cooperating abutment on said armature.

23. In a magneto, of the type wherein an armature moves toward and away from a magnetic pole to vary the reluctance of a magnetic circuit by increasing or diminishing an air gap therein, means for varying the degree to which the armature approaches said pole to thereby vary the electrical out put of the magneto and compensate for variations in armature speed.

2%. In a magneto, of the type wherein an armature is movable toward and away from a magnetic pole to vary the reluctnce of a magnetic circuit, means for varying the timing of the sparks generated by the magneto, and means controlled by the Variation in timing to increase or diminish the electrical output of the magneto at any given armature speed accordingly as the spark is retarded or advanced.

In testimony whereof I have aflixed my signature.

PHELPS BROWN.

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