US1428083A - Magneto - Google Patents

Description

H. F. GEIST.

MAGNETO.

APPLICATION FILED ocT. 30, 1920.

1,428,083, PatendSpt. 5, 1922.

2 SHEETS-SHEET I.

Hmrffr f QEIST Patented Sept. 5, 1922.

HARRY FOREST GEIST, OF HARTSVIL'LE, SOUTH CAROLINA.

MAGNETO.

Application filed October 30, 1920. `Serial No. 420,776.

To all whom t may] concern:

Be it known that I, HARRY F. GEIST, a citizen oi the United States, residing at llartsville, in the` county of Darlington and State ot' South Carolina, rhave invented new anni useful lmproveu'lents in Magnet-os, of which the following is aspecilicatifon. e

The invention relates to magnetos for ignition purposes.

The invention is more particularly designed to provide a magneto of the armature wound type, in which by reason of the construction of the lield pole pieces and the armature, a magneto of etlicient magnetic and electrical propertiesis obtained. The invention is further designed to 'provide magneto ofthe armature wound type which may be readily assembled or taken apart due to the simplicity oi its construction and the arrangement of its parts.

The invention consists further in the several features hereinafter set forth and more particularlyv defined by claims at the conclusion thereof.

In the drawings, i

Fig. 1 is an end elevation oitthe device, with the interruptor housing cover removed and the cover supporting spring and interrupter timing lever out away.

Fig. 2 is a vertical section on the line `11 oit Fig. 1.

Fig. 3 is a vertical section on the line 2-2 of Fig. Q. y

Fig. ft is an horizontal section on the 3-3 of Fig. l. i i

Fig. 5 is an isometric view of the special pole piece.

Fig. 6 is a diagram of the` electrical oircuits of the device.

For convenience in explanation, the mechanical construction ot the trame, field, armature and interruptor will be' described lirstand the circuit connections et the `machine together with its operation, thereafter.

The trame consists o1 the portion 10 having a base 11 adapted to be mounted on any suitable `support adjacent to the engine to which the magneto is operatively connected.

rfhe ield consists of pole shoes designed as a whole 12 and permanent magnets 13 contacting with said pole shoes and con nected to the frame by a metal strip 14.- surrounding said magnets and connected at its lower ends to the frame 10 by any suitable means, such as screws 15,

The pole shoes are of special construction line so as kto reduce the iron losses due toeddy currents as much as possible and vto reduce the time constant of the secondary winding. These pole shoes consists of a plurality of soft iron laminae 1.6 clamped between solid iron or steel blocksdy by means of rivets 18, both` the laminze and the blocks contacting with the magnets and lhaving., their inner sides curved to 'accommodate the armature, as shown in Fig. 3. The laminas 16 used in the Held serve to break up the eddyY currents which travel throughy the field at righty angles to the plane of said laminas and thus reduce the iron losses ofthe field. ,Holes or recesses 19 are provided in the blocks 17 to reduce the cocliijcient of self-induction of the secondary winding and by so doing re,

duce the time constant of the secondary winding. The laminas 16A are also so shaped as to present themselves to the bore of the machine, for close magnetic coaction with the armature, atthe pole shoe tips only, the central area being cutaway to form a connecting recess betweenthe recesses 19 of the parts` 17.` The pole shoe considered as a whole is therefore of basin shape as shown by Fig. 5 andthe recess asawhole does not penetrate through the `pole 4shoe but allows a bottom or web formed byback parts 20 of the parts 17 andthe laminae for Contact with the polar faces of the magnets. 13 as shownV by Fig. .45. Ay further advantage gained by this basin shaped recess is that for sparljing positions of' the armature such as in the neighborhood,o1 that shown in Fig. 3the centralpole pieceareas will be sufliciently distant `from the high tension or secondary winding to reduce highv tension energy leakage to` a minimum.

For convenience in manufacture, the frame 10 is cast around the laminael and blocks 17 by a .die-casting method so that the whole terms a .unitary structure having a bore Q1 therein yto receive. the` armature and its bearings'. y

rEhe armature consists of an I-shaped core formed by I sh aped sott iron laminaeJ 22 and 23 clamped between solid iron pieces 24; and 25 having extensions 26 and 27, all being securely fastened together by screws or rivets 28 to form anintegral core and further consists of the armature windings hereinafter described. The laminas 22 and 23 are provided-in the core to reduce. the 'iron losses by breaking up'the eddy currents set up therein, The laminae22 are narrower at 'the central portion which passes directly through the windings than is true et the lamine and the parts ot 24C and 25 which pass through the windings7 so as to allow the central parts ol the core to be spaced from the primary winding. ylhe purpose oit this spacingis to malte the diii'erent layers of the primary winding` more nearly et the same electro-magnetic characteristics. littention is called, herewith, to the tact that the armature core construction which permits the primary windings to be spaced Ylirom the central parts oit the core by reliefs therein thought to be new and novel; that is made a part el and claimed in a eopending` appli ation, Serial #321,065 tiled Septembei' 2ndi 1919, Yfor magnetos olil similar type and will not thereitore be claimed in this application. The solid parts 2land 25 with their extension 26 and 27 form continuations of the coil space recess of the I shaped laminfe and continuations also of the curved 'faces et the laminae7 forming as a whole a core adapted to carry a winding` and to present face areas for coaction with the pole shoes that are joined by a portion that passes directly throughthe windings.

The extensions 26 and 27 of the solid iron blocks oi the armature core are provided with holes or apertures 29 that are intended to reduce the time constant of the secondary winding. The extension 27 at the driven end of the armature core is provided with flanges 30 of larger diameter than the rest of the armature so as to provide a substantial means of securing the driving shaft plate to it, Special provision is made in the bore 2l of the machine to receive the large diameter end et the armature in the term oit a counterbore.

It will be noted from Fig. 3 that the ends ot the armature core 'faces overlap the gap between opposite pole shoes, so that the magnets are never open circuited.

rlhe armature windings comprise a primary coil 3l which is insulated 'from the core and a secondary winding 32 that is insulated. from the primary windings and. trom the core, both coils being,` wound around the web portion oit the I shaped core between the armatifire laces. rlhe primary coil is grounded to the core by having one ol its terminals Il?) connected to the core by a 4grouuding screw 34h The secondary is also grounded to the core by having one oit its terminals soldered to 'terminal 33 ot the primary windiup; :is is usual in such devices.

llibre plates 35 are employed to lill the spaces made b y the difference between the widths of laminee 22 and 23.

The armature is provided with a brass or other non-magnetic end plate 36 suitably dowelled and secured at its drive end to the core extension 27 havingl rianges 30. The lai-e 56 has the armature shaft 37 xedly mounted therein in a manner well known to Lahe art. rlhe armature is further provided at its other end with a brass or non-magnetic plate harinc a shaftprojection or boss 39 integral with it. The sha'i'ft Si is journalled in a ball bearing' l-.O mounted on a bearing plate il that is secured to the frame l() by screws through which the shalt extends and wliich forms a traine end plate. rlhe shaft 37 is connected up to any suitable source olf power tor rotating` it such as a gear connection with the engine, and the shalt extension of the armature end plate 3S is joui-nailed in. a ball bearing il mounted. on a bearing' plate l-l that is secureil to the frame l0 by screws @n the removal oi' the end plate Ll-.l and the ln'ealLer parts. th r whole armature may be withdrawn lrinn the traine. rl`he primary circuit is also provided with a suitable condenser e@ mounteafl. on the ar- 1iai.re end plate 38 by means olf a threaded j'ilate et? and a cap screw 4:8 which also ser ves to secure the interrupter in position as hereinafter descriliied.) the condense r being insulated Ylrom the conductor parts by a plate il? and bushing` 50 oit insulating' material.

One terminal et the condenser grounded to the core by the screw Slirlhe interruptor consists oil. a metal disk 5l having;- a tapered projection seated and lreyed in a :female tapered seat of the sha it projection. 39 of the armature end plate 38 nd hav.. o' mounted thereon but insulated. therefrom contact carrying' member 52. The plate serves to insulate 5l trom Ji sciare-w 541 passing through an insulating bushing` serves to tasten 5l and. 52 together. The screw e8 passing' through a hole in the contact carrying` member and through a hole in the tapered projection of the dish 5l con'ipletes the electrical circuit between the condenser flo and the interrupter contact carrying member 52 through the threaded condenser plate el? which represents one terminal et the condenser.

Th screw LS also serres to mechanically secure the interrupter mechanism lixedly but removably to the armature and in lceyed relation to it.

gli. contact lever 57 is pivotally mounted on the disk 5i and is infevided with a contact point 5S adajited to ei'igi'age with an adjustable contact 59 mounted upon a screw (SO that asseuibles to the member and may be adjusted and locked in place by the nut Gl.. The contacts 5S and 59 are normally held in contact with each other by means oi a spring 62 secured. to the lever 57 at one endv by screw 6a and to the dish 5l at the other end by a screw 68. lVhen in contact, 58 grounds the insulated contact 59 to the armature core by .means et the lever 57, the spring- 62 and the disl: 5l and the circuit is interrupted by breaking the contact between 58 and 59 by means of a fibre bumper blocs:

lOO

that engages a cam` 66 that is carriedl upon an adjustable sleeve 67 mounted upon a cylindrical boss of the bearing plate 44, and is provided with an operating lever 68 that controls the time of break at the interruptor and its relation to the position of the armature core with respect to the eld pole shoes,

with one or two cams 66 dependingupon the number ot sparks desired per revolution of' the armature and depending also upon the means for collecting and distributingthe high tension spark current.

The interrupter lever 57 is held in place by a spring 69 that is secured to the disk 51 by means of a screw 70.`

The interruptor mechanism is covered vby a plate cover 7l that tits over the outer end oil' the sleeve 67 and is held removably in place by a spring 7 3 which is mounted upon a post 72, said post being assembled `to the base or other part of the trame casting l0. i A means is also provided for collecting the high tension current from the secondary circuit on the armature, consisting of a collector ring 74; mounted in an annulargroove of a spool 75 that is` made of' insulating material, said spool being mounted directly upon the armature drive shaft 87. The ring 74 is connected electrically to the secondary coil by an insulated lead or terminal conductor wire 76 which passes through an insulating boss 77 on spool'75V that projects through a hole in the armature end plate 86.

ik contact brush 78 yieldingly slidably inountedivith a spring 8O in a binding post 79 contacts with the ring 7 t, the post 79 and brush 78v being insulated from the frame 10 by a socket member Sl ot insulating material. The contact brush 78 is adapted to be connected to the spark plug of the engine `by means of the binding post 79.

place by a spring 83 which is secured tothe trame l() by a screw 84E servesto ground the armature to the frame so that high tension current will not pass through the ball bearings. j j

A `circuit wire 85 connects the primary coil directly 'to the insulated lead of the condenser and thence to the insulated member of the rnterrupter by the cap screw 48, so

that when the contacts`58 and 59 of the interrupter are normally together, both the primary coil and the condenser areshort circuited through them. l IniFig. 6, I have shown the electrica-l circuit connections ofV the device in a diavA"discharge brush 82 held yieldingly in grammatical manner, showingithe relation between the primary coil, the secondary coil, the interrupter and the condenser. These connections are the same as is usual in devices of this class.

The Fig. 6 shows the primary coil 31 and the condenser 46k connected in multiple and so connected to the interrupter that the interrupter contacts 58 andl 59 either close or open both the primary coil and the condenser circuits at the same instant.

vThe secondary coil 32 which iswound directly over the `primary* coil on the armature is open circuited for the production of a1"jump spark at the spark plug of the engine.

'lhe operation ot the device is as follows.

As the armature passes vfrom the horizontal position to the vertical position shown in Fig. 3, the tendency is for all of the magnetic flux to pass or shift'from complete interlinkage with thecoils to a set of bypass magnetic circuits outside of the coils entirely. These by-pass circuits are formed by the armature faces` Which bridge the pole shoe tip gaps.. As rotation continues beyond the vertical* position the fiuX of course shifts back into interlinkage with the coils in the reverse direction. The maximum rate of flux shift takes place in the neighborhood ot the `vertical position so that it is during just a few degrees of' rotation, after the vertical position has been passed, that the maximum Aenergy generation takes place. The prima-ry coil is short circuited during the period that the armature is advancing from the horizontal to the vertical position and allows a maximum amount of energy to be` generated and stored lin its windings and the interlinked magnetic circuit, in the form off electromagnetic energy. The condenser andf the secondary areA both inoperative during this period, due to the short circuit condition of the condenser and the open circuit of the secondary.

`Then the energy generation and storage reaches about its maximum, just after the vertical position has been passed, the inten rupter functions and brings the condenser sudden-ly into the circuit, at the same in- 115 stant that the energized primary coil is open circuited.

The combined results of suddenly checkin the energization of the, primary coil and su denly putting the condenser under con- 120 ditions for its energization is that a very high vol-tage will be induced'in the windings of the coils. Because of the yfact that the secondary coil is wound with a high c number of turns 'this induced voltage will 125 be high enough to produce a jump spark at the spark plug of the engine. The condenser will absorb the energy lett in the primary and thus prevent arcing at the inter-V rupter contacts, The phenomena fjustre- 130 ico viewed are in general coninion to )'nactically all self-contained high tension. niagnetos of which my device is one.

In my invention the electrical phenomena are especially elticient due to the special construction of the pole shoes and the arma-ture core which permit the electrical energy to be handled during the period ot sparking very quickly. The basin shaped recess in the central portions ot the pole shoes and the apertures oif the armature extension castings are n.ovided to remove as much .iron from the innnediate presence ot the secondary winding during the sparking period as possible, so as to reduce the tendency ot any lag that would be caused by such iron, to a minin'iuln. rllhe basin recess also reduces the amount of high tension energy leakage between the secondary winding and the pole slices to a minimum.

T he reduction ot both the lag and the energy leakage by the removal o'li' iron from the presence of the secondary in the torni ot recesses must not reduce the generative ability oit the machine. This is taken care oit in the magnetic circuit design by giving the pole shoe parts 17 and the laminae 16 ample area at the bore oi the machine for close magnetic engagement with the armature faces for all positions of the armature. It will be noticed that the tip edges ot the pole shoes are maintained as long as possible so as to produce a quick magnetic break with the long edges et the armature core faces.

The lamin also form a very efficient tie between the upper and the lower pole shoe tips in both pole shoes for handling the flux changes that take place from one pole tip to the other during the rotation oit the armature.

It is Very evident that these lamime do not have to come flush with the liore of the machine throughout the entire span from pole tip to pole tip in each pole shoe, so that it ls possible to recess the laminas and get plenty or' clearance between them and the secondary windings for the purposes set forth.

The advantage gained by the special construction ol the magnetic circuit, which reduces the time-constant ot the windings and reduces the energy leakage, is not alone that it permits oit the delivery of a very quick and. eiiective spark, but permits the use ol fewer secondary turns, other secondary circuit conditions being the same.

I am aware that the specific construction herein described is subject to modifications and changes and I therefore desire it to be understood that such modiiications and changes as come within the scope of the appended claims are within the spirit of my invention.

What I claim as my invention is.

l. In a wound armature type magneto, the combination of a revoluble armature and windings with a field structure comprising a trame, field magnets and pole shoes, said pole shoes being substantially a hollowed square in shape to reduce the central inagnetic areas presented tor (io-operation with said armature.

2. In a wound armature type magneto, the combination ot a revoluble armature carrying windings with a field striuture comprising a traine, field magnets and pole shoes, said pole shoes each inchuling an area of contact with said magnets, and an area for co-operation with said armature, said arca toi' co-operation with said armature beine' centrally relieved to reduce the proximity of said area to said wiiulings without decreasing the area ot' contact ot said pole shoes with said magnets.

3. In a wound armature type magneto, the combination ot a revoluble armature carrying windings with a iield structure conin prising a iframe, field magnets and pole shoes, said pole shoes having recesses to reduce the central magnetic areas in proximitylto said windings, said recesses having bottoms in said pole shoes to maintain a :tull area ot contact between said. pole shoes and said magnets.

il. In a wound armature type magneto, the combination of a revoluble armature and windings with a field structure comprising a traine, field magnets and pole shoes, said pole shoes comprising a plurality ot' laminas presenting spaced apartprojeetions for cooperation with said armature, said projections being` integrally connected by a web section, said lamin being clamped together between solid iron parts.

5. In a wound armature type magneto,

the combination of revoluble armature cairying windings with a lield structure coni- ]'ii'ising a frame, field magnets and pole slices. said pole shoes comprising a plurality oit sott iron laminae presenting spaced apart projections tor co-operation with said armature and parts contacting with said magnets, said spaced apart projections forming central area reliets, said lamina; being clamped between solid iron parts having .reliefs in line with said lznninated section reliefs, said solid. parts also having parts in contact with said magnets in line with said parts of said laminae in contact with said magnets for maintaining tull contact areas with said magnets.

6. In a wound armature type magneto, the combination ot a revoluble armature and windings with a field structure comprising a trame, field magnets and pole slices, said pole shoes comprising areas ot contact with said magnets and areas for co-operation with said armature having upper and lower tip edges, said polar area for co-operation with said armature being centrally relieved without reducing said areas ot contact with said magnets and Without reducing the length of said pole shoe tip edges for the purpose described.

7 A revoluble armature far apparatus of the class described, comprising windings, au iron core, ka non-magnetic end plate With drive shaft projection and a non-magnetic end plate with other shaft projection, said iron core comprising face area sections connected by an integral section through said windings, said non-magnetic end plates be- `ing mechanically secured at each end oit' said core to the ends of said face area sections,

said ends securing to said drive shaft non-` magnetic plate being flanged to a larger diameter to give a more rigid connection with out increasing the diameter of the rest of said 'armature substantially as described.

8. A revoluble armature `for apparatus of the class described comprising windings, an iron core, drive end non-magnetic plate and other end n0n-magnetic plate mechanically secured to said core, said drive end nonmagnetic plate and said core being of larger diameter in their connection than said other end plate and the rest of the iron core to provide a more rigid mechanical connection at said drive end.

HARRY FOREST GEIST.

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