US2015697A - Magneto - Google Patents

Description

' Oct. 1, 1935.

M. E. SPQHN MAGNETO Original Filed June 6; 1951 3 Sheets-Sheet 1 uwijyrox.

h ATTQRNEY way/$16 BY 6/ v 06L i, 1935. SPQHN 2,015,697

MAGNETO Original Filed June 6, 1931 3 Sheets-Sheet 2 HYTITI// INVE TOR.

fis ATTORNEY Original Filed June 6, 1931 3 Sheets-Sheet s 64 54 INVE TOR.

ATTORNEY Patent dfl t. 1, 1935 PATENT OFFICE 2,015,697 MAGNE'I'O Malcolm E. Spohn, Sidney N- Y., assignor'of onehalf to Edson C. Burdick, Bainbridge, N. Y.

Application June a, 1931, Serial No. 542,586

' Renewed June 9, 1934 Claims.

This invention relates in general to generators of the magneto ype, and more particularly to a magneto for supplying electrical energy for igniting the working substance of a prime mover, such 5 as an internal combustion engine. The adaptation to which the invention is primarily susceptible is in connection with prime movers of a type which require more than a single ignition spark per cylinder, such as is presently employed in the dual ignition system of airplane motors, where the safety factor of the machine demands such positive ignition. It is equally suited for use in other types of internal combustion engines which require, and may in the future demand because of the present trend toward increased motor speeds, a double, or if necessary, a greater number of independent ignition impulses per cylinder. The advantages of such an ignition system result in a more positive and thorough ignition of the compressed charge causing a more complete combustion of the working substance in the cylinders of the engine to thereby attain a greater over-all efficiency of the motor.

Heretofore in certain automotive vehicles and airplane engines it has been necessary to utilize two independent magnetos to obtain the benefit inherent in a. dual ignition system. In some instances the electrical generators have also been combined into a single unit in order to reduce weight, particularly in airplanes, but the construction has necessitated the use of two individually driven distributors.

The primary object of the present invention is therefore to construct a unitary magneto which will simultaneously generate and distribute therefrom any desired number of electrical sparking impulses to the ignition points of,an internal combustion engine.

40 Another object of the invention is to provide a magneto rotor in which there is a plurality of bar magnets, the polarities of .the respective magnets being arranged to provide an altemating magnetic flux. The magnets on the rotor 45 having similar polarities are strengthened by inter-locking laminations. Each magnet'separate from the remaining magnets of like polarity is adapted to cause an independent magnetic field through the pole shoes and the core of a 50 coil so that a sparking impulse is obtained. The number of individual magnets preferably utilized on the magneto rotor of this invention corresponds to the number of cylinders in the engine 55 with which it is associated so that one revolution of the magneto rotor will provide a suflicient from the accompanying drawings, in which I number of sparking impulses to fire each cylinder of the motor.

A further object is'the provision of a magneto in which the distributor and generating elements are mounted'upon a single shaft thereby 5 eliminating the heretofore necessary gearing as-' sociating these elements and also by this simplified construction reducing the number of necessary bearings in the magneto. By reducing thenumber of movable mechanical parts of the 10 magneto the efliciency is raised and the chances of failure of a given element are minimized.

' Another object is to provide a magneto of this type in which the generating and distributing elements rotate at the same speed. 15

Still another object is to provide a magneto in which all moving parts will rotate at one-' half engine speed and thereby prevent an internal overheating of the generating elements which is a frequent occurrence in high speed 20 'magnetos.

The invention also anticipates the utilization of an electrical generator of this type in which a plurality 'of separate pole shoes and cores are fixed in desired position about the magnet rotor 25 so that each core may simultaneously and individually be affected by an alternatingmagnetic field. The coils are each provided with a breaker mechanism by which the primary current may be interrupted and the secondary current controlled to synchronize or stagger the sparking impulses depending upon the requirements of the motor with which the magneto is used.

While for purpose of simplicity in illustration the invention has been shown as comprising only a pair of such pole shoes and cores so that obviously dual ignition is obtained, it will be apparent that by increasing the number of these elements about the rotor any desired number of sparking impulses may be effected per cylinder. My invention further includes other objects, advantages and novel features of design, construction and arrangement hereinafter more particularly referred to and which will be apparent have illustrated the same in its preferred form. In the drawings Figure 1 is a side elevation of a magneto made in accordance with the present invention, Fig. 2 is a plan view of the device as shown in Fig. 1.

Fig. 3 is a sectional view taken on line 3-3, Fig. 1.

Fig. 4 is a sectional vlew taken on line 4-4, 1 1'18. 3.

tion rotor, or a magnetic flux producing member, and stator members effected by the flux producing members, together with a distributor element and breaker mechanism are associated and contained within a unitary framework or casing. As shown this casing preferably includes a base member it formed to make provision for the bolting, or securing in any other desired manner, of the same to p as desired.

the body of the engine. The central portion of the base II is constructed to make provision for a bearing II and rotatable spindle or shaft l2; An end plate ll suitably fastened to the base I0 prevents an axial displacement of the spindle i2 when in operative'position in the casing. The end of the spindle I 2 projects from the end plate of the base member and is adapted to either be geared to the cam shaft of the engine at an equal speed,

ratio or may be directly connected to the same It will be consequently understood that the rotating speed of the induction rotor of the generator is equal to the cam shaft speed of the engine which is always one-half the R. P. M. of the crankshaft.

Semi-sections of housing as indicated at I4 and I! are secured to the base member, and include in their present construction, end portions l6 and I! when connected for enclosing the stators of. the generating elements. A distributor cap I8 is mounted above the housing members I4 and i5 and is preferably secured thereto by removable fastening means such as clips as indicated at II. The construction of the housing members I! and II also provides for a centralbearing member 20 v a for the other end of the spindle I2.

70 In order to construct an induction rotor composed Referring particularly to Figs. 3 and 5, the induction or rotor element of the generator comprises a plurality of individual bar magnets each fixed in positionat equal radial distances from the spindle l2 by means of and between circular holdlng plates 2| and 22; For purposes of illustration, I have shown eight such magnets parallel to ;the axis of the spindle and spaced at equal arcu ate distances from each other about the periphery of the rotor. The individual magnets on the rotor are separately adapted to cause a magnetic flux in each stator element of the generator, so that as illustrated in the present case, the eight magnets will cause eight corresponding sparking impulses to simultaneously emanate from the coil of the respective stator elements for every revolution of the cam shaft of the motor. It is apparent that any number of magnets could thus be placed on the rotor in accordance with the present invention to obtain the necessary sparking impulses to fire each cylinder of an engine in one revolution of the rotor.

The bar m snets are preferably arranged about the rotor so that the polarities of the same alternateinordertoobtainareversal ofthedirection of magnetic flux in the coil cores. The positive polarities of the magnets are indicated generally at 23 and the negative polarities at 24.

of manyindividual magnets, which will maintain its magnetic strength for a long period of time, I employ interlocking lamination sheets for associating the magnets of like polarities on the reemployed on the magnets of negative polarities. 5

The lamination sheets 26 are built slightly higher than the interlocking laminations 25 in order to I separate the same from the interlocking laminations 21 for connecting the negative poles of the magnets. The lamination spacer sheets 28 are 1 adapted to be placed in position on the extremities of the magnets having positive polarities. The sheets of lamination employed below the holding plate 22 associate the magnets in a like manner. The laminations employed are pref- 15 erably of thin sheet steel, the sides of the respective sheets being oxidized in order to minimize so far as possible the formation of eddy current magnetic lines of flux within the rotor.

As illustrated, I employ circular brass end plates 20 29 and ill for retaining the lamination sheets firmly in position on the rotor. The end plates are secured in position on the rotor structure by fastening screws which may be turned to position in tapped openings at the extremities of the 25 magnets. However, in the event that the magnets are made of a. very hard cobalt'steel the end plates may be secured to the rotor in any other manner such as fastening the same by screws to the holding plates 2| and 22 respectively. The rotor in- 30 duction element of the generator as assembled is compact and rigid in construction and efllcient in operation.

Referring particularly to: Figs; 3 and 4, the stator elements of the magneto are illustrated. as In this instance only two independent elements are shown in order to effect dual ignition. The stator elements are similar in construction and are placed 180 apart when two are utilized. The invention also contemplates the use of as many such 40 elements as may be required to produce a desired number of sparking impulses per cylinder such as may be provided by a housing which will enclose three stator elements spaced 120 apart, or four stator elements at 90 apart, as such a construction in connection with the rotor element described will obviously simultaneously produce three or four sparking impulses respectively per cylinder.

As shown the construction of the stator element includes'pole shoes II and 32, a core 33,

ing their extremities curved so as to expose the face of the shoes to the rotary induction element.

As clearly shown in Fig. 3, as each individual magnet assumes a position ,shoes, lines of magnetic flux traverse the stator element. The magnetic 'field caused by each magnet is represented by the arrows passing from the extremity of the magnet 23 of positive polarity,

through the shoe 3|, core ll and shoe 32 to the extremity of the same magnet having a negative polarity. The individual magnets are arranged on the rotor so that magnetic flux will be produced in each of the stator elements simultaneously. The path of the magnetic field will be reversed in adjacent the pole arms have the 1.18:2!

the coil cores by the action of the successive magnets of alternating polarities as they assume a position adjacent the pole shoes. The pole shoes and cores. are preferably constructed ofsheets of laminated steel having oxidized surfaces simithat in the construction illustrated eight separate sparking impulses will be generated simultaneously from each of the coils of the stator elements for each revolution of the induction or rotor element.

Referring particularly to Figs. 3, 4 and 6, the magnetic flux, simultaneously effected in the respective cores of the stators, induces an electric current in each of the windings. The flow of the current through the windings is adapted to be interrupted by a breaker mechanism when the same reaches its highest intensity. This mechanism is. preferably centrally located above the housi g sections l4 and I5 containing the bearing 20, it eing suitably insulated therefrom and is controlled by a cam 38 keyed to the end of the rotor shaft I2 which extends above the-housing. A rotatable base plate 39 having slots is indicated at 40, by which the same may be retained in a fixed position by screws 4| facilitating an adjustment in the setting of the plate to obtain the proper timing for the sparking'impulsesof the engine.

As shown for the purposes of dual ignition, I employ an individual breaker arm for each of the generator stator elements. The breaker arms are indicated at 42, being pivotally secured to the.

plate 39, the same having cam cooperating points operative on opposite sides of the cam 38. Suitable means, such as leaf springs 43, are associated .with the breaker arms so as to maintain the cam follower in cooperative relationship with the cam at all times. The ends of the respective breaker contact points 44 adapted to cooperate with e adjustable contacts 45, the supporting members of which are suitably insulated from the base plate. A lead 46, Fig. 6, conne'cts one of the contact points 44 to the primary winding of one of,thstator elements. A lead 41 makes a similar connection to the other stator element. Leads 48 from each of the contacts 45 are employed to facilitate the grounding of the primary current in the stator elements. The cam 38 of the breaker mechanism, being directly conriected to the shaft I2 on which the induction element is mounted, necessarily rotates at one-half.

engine speed.

For the purpose of the present invention, the cam must be provided with a plurality of equidistant spaced lobes corresponding in number to the individual magnets as employed on the rotor so as to'cause a break or interruption in the primary current induced in the stator by each m'ag-' net. The cam provided in the instant case must necessarily, therefore, have eight lobes as illustrated, the same being adapted to cooperate with ,the breaker arms to cause a simultaneous interruption of the 'primary, current in the respective coils. The base plate 39 and the contacts may be adjusted to any desired position to either synchronize or stagger the ignition impulses in order to meet the requirements of the motor with which the magneto is used. I

, Referring to Figs. 3 and 6, the distributor rotor or disc 49 of the magneto, operative within the distributor cap it, is illustrated. This rotor is fixed to the end of the shaft I! by a set screw or other means and is located above the breaker mechanism. The distributor cap is provided with individual leads from each of the secondary windings of the coils. The lead 50 connects one of the high tension windings to the distributing point 5| within the cap. Similarly the lead 52 connects the other secondary winding to the distributing point 53. The rotor or disc 49 is constructed to facilitate an individual and simultaneous closing of the high tension circuit to make communication at the desired instant with the sparking elements of the engine.

In accordance with the present invention eight duplicate distributing points of contact are made for one revolution of the rotor element 49. I One group of contacts are spaced about the periphery of the distributor disc as indicated at 54, the same having leads to the respective cylinders of the meeting the high tension circuit to a spark plug 51, and a lead 58 performing a similar purpose for spark plug 59.

The rotor is constructed to include on its lower surface an intermediate strip 60 of conducting material connecting the high tension contact 5| 'to a contact 6| on the periphery of the disc. The contact 6| makes a connection with each of the eight distributing spaced contact points 54 at the sides of the distributor cap in one revolution of the rotor. At the top surface of the rotor 49 a circular conducting strip 62 is shown making contact with the high tension point 53 at all times. An arm 63 projecting radially from the circular .strip 62 is adapted to close the circuit to the disb tributor contacts 55 located in the top of the distributor cap at the desired intervals. The contacts of the rotor element simultaneously close the separate high tension circuits to each of the spark plugs'of a cylinder and distribute eight of such dual sparking impulses for every revolution of the rotor l2. The construction employed in accomplishing the objects of the present invention also. makes it possible to mount the distributor, or the breaking mechanism and the induction rotor element on a single shaft thereby eliminating the heretofore necessary gearing.

Referring particularly to Fig. 6, a lead 54 from each of the primary windings of the coils may be utilized to short circuit the current supplied to the breaker mechanism so that the same can be directly grounded when an operating switch 65 is closed in order to stop the engine.

Also the magneto may be suitably provided with a booster'or starting current line as indicated at 65 associated directly with the distributor in order to facilitate the starting of the engine, by initially flringthe cylinder by means of an independent source of electrical energy.

It is also apparent that the construction utiliied eliminates the necessityof making specific provision for the radio shielding of the magneto at the contact points/ofhigh tension current inasmuch as the coils are connected directly to the.dis-

tributor by leads which are located exteriorly of the casing. a

From the foregoing description it will now be circuits in the stator, like polesat the respective tioned about its shaft l2 creates a primary current in each of the stator windings the interruption of which, by the break of the current at the contacts 5 under the influence of the cam 48, causes the high tension current in the secondary windings of the stators. The dual distributor completes the high tension circuit at the desiredinterval to cause the sparking impulses in the respective cylinders of the engine.

It is apparent that the foregoing description in connection with the drawings is, merely illustrative for the purposes'of explaining the invention as it may be utilized to suit the requirements of a given type of engine.

Claims to subject mattercommon to this application and my co-pending application Serial No. 739,728, filed August 14, 1934, are being made in said co-pending application, which is a continuation in part of this application.

I claim as my invention:

1. In a magneto, an induction rotor element having a plurality of individual magnets positioned about its periphery and arrangedsothat their polarities alternate, each magnet being parallel to the shaft of the rotor, a stator element having a core, parallel to the magnets, and pole shoes adiacent the polar ends thereof so that in the course of rotation of the rotor element the individual magnets will cooperate with the core and pole shoes to complete alternating magnetic ends of the rotor being magnetically connected but the groups of magnets having opposite pol larities at the respective ends of the rotor being magnetically unconnected.

-2. In a magneto, an induction rotor' element having a plurality of individual magnets posiperiphery and arranged so that their polarities ,alternate, each magnet being parallel to, the shaft of the rotor, means for magnetically connecting magnets having like polarities at the respective ends of the rotor, a stator element comprising a core and pole shoes, said core being disposed in parallel arrangement to the shaft of the rotor, and the respective pole shoes thereof "adjacent in relationship to the polar ends 'of the individual magnets, the group of magnets havingits positive poles at an end of'the rotor being magnetically unconnected to the group having its negative poles at said end.

3. In a magneto, an induction rotor element having a plurality of individual magnets spaced having a plurality of individual magnets posi 9,015,697 ,to, the rotation of the induction element on the about its periphery and arranged so that their polarities alternate, each magnet being parallel to the shaftof the rotor, a plurality of stator elements spaced about the rotor, each stator having an individual core and pole shoes, the cores 5 being disposed in parallel arrangement to the shaft of the rotor and the pole shoes extending perpendicularly'therefrom to a position adjacent the polar ends of the magnets, like poles at the respective ends of the rotor being magnetically connected but the groups of magnets having opposite polarities at the respective ends of the rotor being magnetically unconnected.

4. In a magneto, an induction rotor element i5 tioned about its periphery, each magnet being parallel to the shaft of the rotor, a plurality of stator elements having independent cores and pole shoes spaced about the rotor, the cores being parall to the shaft ofthe rotor and the pole 2o shoes ext nding perpendicularly therefrom to a position adjacent the polar ends of the magnets so that, in the course of rotation of the rotor element, the magnets will cooperate with each of the,.cores and pole shoes to simultaneously complete a magnetic circuit in each of the stators, each magnet being magnetically connected at its respective ends to all the other magnets having a corresponding arrangement of the poles along the rotor axis but being magnetically unconnected to those magnets which have areverse arr gement of the poles along the rotor axis.

5. a magneto, an induction rotor element havin a plurality of individual magnets spaced about ts periphery and arranged so that their polarities alternate, each magnet being parallel to the shaft of the rotor, a plurality of stator elements spaced about the rotor, each statorhaving an individual core and pole shoes, the cores being disposed in parallel arrangement to the shaft of the rotor and the pole shoes extending perpendicularly therefrom to a position ad- Jacent the polar ends of the magnets so that in the course of rotation of the rotor element the individual magnets will cooperate with each of 5 the cores and pole shoes to simultaneously coniplete alternating magnetic"circuits in each of g the stators, like poles at he respective endsof the rotor being magnetic 1y connected but the groups of magnets having opposite polarities at the respective ends of the rotor being magnetically unconnected.

MALCOLM E. SPOHN.

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