Oct. 7, 1952 - _ E, G, MACKAY ‘ 2,612,886 MAGNETO IGNITION SYSTEM FOR INTERNAL-COMBUSTION ENGINES

Filed June 21, 1949 _ '

-1.1.2) . Patentecl Oct. 7, 1952 2,612,886

UNITED STATES PATENT orrics 2,612,886 MAGNETO, IGNITION‘ SYSTEM FOR ‘ INTERNAL-COMBUSTION ENGINES Eric Glen Mackay, Hawthorn, Victoria, Australia Application June 21, 1949, Serial No. 100,466 In Australia August 5, 1948 12 Claims. (Cl. 123-148) ' 2 1 able type of magneto having an induction coil This invention relates‘ to magneto ignition sys 2 provided with primary and. secondary windings tems for internal combustion engines and the 3 and 4 respectively and a battery 6 or any other like, especially slow starting aircraft and other suitable source of direct current which is wired multi-cylinder engines which are adapted to op in circuit with the primary winding as herein erate at relatively high speed. More particularly after described. ‘ the invention concerns that type of magneto ig Means for making and breaking the battery nition system which includes a battery or the current are also provided and such means pref like to provide a supplementary source of cur erably consists of a pair of relatively reciproca rent. 10 tory contacts or the like ‘I. A driven cam 8 hav The advantage of battery ignition over mag ing any suitable number of lobes is provided for neto ignition for starting purposes and of mag actuating the contacts which preferably have a neto ignition for high speed are well recognised condenser 9 associated therewith to minimize but when the two systems are combined, di?i culties are encountered in that the uni-direc sparking. ‘ 15 Hitherto, a single primary winding has been tional battery current opposes one half cycle of included in the magneto induction coil but in the alternating magneto current. Consequently accordance with the present invention, the pri after starting the engine it has been necessary mary winding includes at least two sections. As to cut off promptly the battery current either seen in Figure v1, two separate primary coils 3a manually or by means of a suitable automatic 20 may be provided. These coils are preferably switch device. ' " wound in longitudinally spaced relationship on Another serious disadvantage in‘ such known the core ll instead of in overlying relationship combination ignition systems is that the alternate so as‘ to ensure the provision of substantially opposition to the flux in the core of the mag matched coils and prevent undesirable interfer neto induction coil tends to demagnetisev or at ence therebetween. least materially reduce the effective strength of 25 One pole I 2 of the battery is connected through the usual permanent magnets of the magneto. the contacts -1 to one end of each primary coil The primary object of the present invention is to whilst the other end of each primary coil and the‘ provide an improved magneto ignition system’ of other pole l3 of the battery are connected to the type incorporating a booster battery or the like earth as hereinafter described. and which is adapted to furnish an effective sup 30 Associated with the foregoing are circuit chang ply of current for starting purposes as well as ing means for alternately including the sections when the engine is running at‘ high speed with of the primary winding in the common battery out having to cut off the supply of‘ battery cur circuit in such a manner that the battery cur rent. The latter is thus utilized to supplement 35 rent ?ows ?rst in one direction in one of the that of the magneto and enables the weight, size primary coils 3a and thence in the opposite di and cost of the system to be materially reduced. rection in the other primary coil to thereby al In addition, the permanent‘ magnets of the ternately reverse the battery current flux in the magneto are maintained in a substantially fully induction coil and induce the equivalent of an magnetized condition as desired whilst at high 40 alternating current in the secondary winding 4. speeds any excess current from the magneto ‘is For this purpose, one pole l2 of the battery is absorbed by the battery. connected by leads l6 either to the adjacent ends Referring to the drawings which form part of the primary coils 3a as shown or to the op of this specification: posite ends thereof and the return leads ll of Figure 1 is a diagrammatic view of the improved 45 the primary coils are connected to said circuit magneto ignition system in accordance with one changingmeans. A rotary switch lever such as embodiment of the present invention. a commutator I8 is preferably employed for this Figure 2 is a view similar to Figure l of a modi purpose as it is particularly suitable for high ?cation. speed work. Figure 3 is a part sectional, side elevation of 50 In the embodiment shown, the number of com a magneto in accordance with one embodiment'of mutator segments 19 correspond to the number the present invention. ‘ . of poles in the magneto and the return lead from Figure 4 is a wiring diagram showing‘ a polar one coil is connected to alternate segments whilst inductor type of magneto included in the im the return lead'from the other coil is connected proved ignition system. ' 55 to the intervening segments for alternatively re The improved ignition system includes any suit 2,612,886 versing the battery current flux in the induction coil as aforesaid. tator for instance through a spring in?uenced If desired, the commutator brush 2| and the contact 31 engaging one end of the shaft. cam 8 of the contact breaker points 1 may be It will be appreciated from the foregoing that carried by the magneto armature shaft or any the invention is not limited to any particular type other common shaft and thus rotate at the same of high or low tension magneto but that it may speed. For convenience of illustration, they are be easily incorporated in the rotating armature shown as mounted upon separate-shafts 22, ‘23 rotating magnet or polar inductor types as may geared together as at 24 so as to rotate at the be required. Furthermore magnetos employing same speed. In this case, the number of cam electromagnets instead of the conventional per lobes correspond with the number of commuta 10 manent magnets may be adopted if so desired. tor segments employed. The arrangement is such A highly e?icient embodiment is illustrated dia that the maker and breaker contacts 7 are open grammatically in Figure 4 of the drawings. In when the brush 2| is crossing the gap between this case the magneto 28 employed is of the polar adjacent segments. Undesirable burning of the ' inductor type and the primary winding of its in segments is thus eifectively eliminated. . 1 5 duction_ coil 2 consists of two matched coils or , 5921301515., The The movements of the maker and breaker con- 0 latter are wired in circuit with a tacts and the commutator are synchronized so battery 6 through maker and breaker contacts that the battery current flow is directed alter 1 and acommutator or the like 18 as aforesaid. nately first to one primary coil 3a and then to For convenience of illustration, the inductor the other primary coil which is connected elec 20 bars 4| are shown mounted on the magneto shaft trically opposite so that the current ?ows in the respective coils in opposite directions for exam ple from the inner to the outer end of each coil. shown mounted on separate shafts 42 and 43 re The ?ux resulting from the unidirectional bat spectively. It will be understood however that all tery current is thus substantially matched with of these rotary parts may be mounted upon or the alternating ?ux of the magneto in the induc actuated by a common shaft if so desired. tion coil. Although it is preferred'by reason of control to It is believed that the primary current is main supplement the magneto current by current from tained substantially constant at all engine speeds a battery, the supplementary current may be in that during slow running, the magneto cur -30 drawn from any other suitable source of direct rent is supplemented by the battery whilst high current such as an electric generator. ' speed requirements are effectively met by the When in use on aircraft an important advan magneto. tage of the improved ignition system is that in When the magneto current exceeds that of the the event of the-battery failing, the engine or battery, the excess current is necessarily diverted engines will not cut out but will continue to func to the battery. Uncontrolled magnetos, strong tion on the current supplied solely by the mag enough to spark at very low R. P. M. such for ex neto ‘provided that a relay or any other suitable ample as 60 R. P. M. are prone to burn excessively manual or automatic means are employed for the spark plug points at higher speed. earthing the magneto’s battery lead. . 40 According to a modi?cation as illustrated in By the present invention, it is possible to obtain Figure 2, the usual single primary winding in the desired reversal of direct current flow in the stead of a pair of separate coils is employed. In primary windings of the induction coil from a this case, the single coil is provided with a sub single battery. Furthermore, the system enables stantially central tap 26 and a common lead 21 a common battery current, a common rotary for example to the maker and breaker contacts switch device and common maker and breaker and battery in order to electrically divide the pri means to be employed. The maker and breaker mary coil into two sections 3b. The opposite contacts and commutator mechanism are of rela ends of this common coil are connected to the tively simple and inexpensive construction and commutator it? as aforesaid so as to alternately are adapted to function ef?ciently at high speed reverse the battery current flux in the induction 50 whilst the size and weight of the ignition system coil. is reduced to a minimum. A suitable practical embodiment is illustrated Various alterations, modi?cations and/or addi in Figure 3 of the drawings. The magneto 28 of tions may be introduced into the foregoing con any suitable type, is provided with a power driven struction and arrangement of parts without de shaft 29 which is adapted to carry both the cam parting from the ambit of the invention as de 8 for the maker and breaker contacts and the ?ned by the appended claims. brush 2i of the commutator. The commutator Having. now described my invention, what I claim as new and desire to secure by Letters segments i9 may be mounted in circumferen Patent is: tially spaced relationship in a sleeve or collar 3! 60 surrounding the shaft and the brush may be l. A magneto ignition system for internal com slidably accommodated in a transverse slot 32 bustion and like engines comprising a magneto in the shaft. having primary and secondary windings forming The brush is spring in?uenced in any suitable an induction coil and a source of- direct current manner. For example, a coiled spring 33 may be wired in a circuit with said primary winding mounted in a pocket 34 in the shaft so as to en which consists of at least two substantially gage one side of an intermediately pivoted lever matched sections, circuit changing means for al 36 on the shaft, the opposite end of the lever be ternately including said sections in the circuit, in ing adapted to engage the rear of the brush. The such a manner that the direct current flows ?rst spring in?uence is required mainly when the in one direction in one of said sections and then brush is rotating at relatively low speed. At high in the opposite direction in the other section to speed, centrifugal force ensures efficient contact thereby alternately reverse the current flux in between the brush and its segments. said induction coil, means for making and break The shaft may also be adapted to provide a ing the circuit and means for synchronizing the convenient earth or return lead for the commu— movements of said circuit maker and breaker 75 means and said circuit changing means with the amaescv ensure that the rotary elements of the magneto movements of the magneto shaft to thereby sub aretraversing the induction coil poles whilst said stantially match the reversing current ?ux in brush is traversing eachof ‘the commutator seg said induction coil with the alternatingimagneto ments and saidcontacts are, closed; ?ux therein and thus provide e?i'c'ient ignition 8,1-A magneto ignition; system according to for engine starting as well as through the rest of claim 1 wherein‘ the ,__circuit is'common to both the engine speed range without having to cut off of, said sections of the primary winding and the current. _ ' ‘ said circuit changingvmeansconsists of a com 2. A magneto ignition system according to mon rotary switch device, and said circuit maker claim 1 wherein the circuit is common to both of 10 and-breaker means consists of a common pair of said sections of the primary winding and said relatively.reciprocatorycontacts» having a con circuit changing means consists of a common denser, associated therewith, said reciprocatory rotary switch device and said circuit maker and contacts being adapted to be operated by a multi breaker means consists of a common pair of rela lobe cam and said rotary-switch device consist tively reciprocatory contacts having a condenser 15 ing of a commutator the segments of which associated therewith. correspond in number withthe lobes on said cam, 3. A magneto ignition system according to the brush of said commutator and said cam being claim 1 wherein said primary winding consists mounted in longitudinally spaced relationship of two separate and substantially identical coils upon an extension of the magneto shaft around wound in longitudinally spaced relationship upon which the segments of said commutator are sup a common core so as to ensure substantial match 20 ported in circumferentially spaced relationship. ing of said coils and minimize undesirable inter 9. A magneto ignition system according to ference therebetween. 4. A magneto ignition system according to claim 1 wherein the circuit is common to both claim 1 wherein said primary winding consists of said sections of the primary winding and said 25 ‘circuit changing means consists of a common ro of a single coil provided with a substantially cen tary switch device and said circuit maker and tral tap connected to a common lead from said breaker means consists of a common pair of rela circuit so as to electrically divide said primary tively reciprocatory contacts having a condenser winding into said sections. 5. A magneto ignition system according to associated therewith, said reciprocatory'contacts being adapted to be operated by a multi-lobe cam claim 1 wherein the circuit is common to both 30 said and said rotary switch device consisting of a ‘of said sections of the primary winding and commutator the segments of which correspond circuit changing means consists of a common in number with the lobes on said cam, the brush rotary switch device and said circuit maker and of said commutator and said cam being mounted breaker means consists of a common pair of rela 35 in longitudinally spaced relationship upon an ex tively reciprocatory contacts having a condenser tension of the magneto shaft around which the associated therewith, said reciprocatory contacts segments of said commutator are supported in being adapted to be operated by a multi-lobe cam circumferentially spaced relationship, said com and said .rotary switch device consisting of a commutator ‘the segments of which correspond mutator brush being spring in?uenced and 40 slidably accommodated in a transverse slot in in number with the lobes on said cam, the brush said magneto shaft. of said commutator and said cam being mounted 10. A magneto ignition system according to on shafts and being adapted to rotate at the claim 1 wherein the circuit is common to both of same speed. 6. A magneto ignition system according to said sections of the primary winding and said 45 circuit changing means consists of a common ro claim 1 wherein the circuit is common to both tary switch device and said circuit maker and of said sections of the primary winding and said breaker means consists of a common pair of rela circuit changing means consists of a common tively reciprocatory contacts having a condenser rotary switch device and said circuit maker and associated therewith, said reciprocatory contacts breaker means consists of a common pair of rela 50 being adapted to be operated ‘by a multi-lobe tively reciprocatory contacts having a condenser cam and said rotary switch device consisting of associated therewith, said reciprocatory contacts a commutator the segments of which correspond being adapted to be operated by a multi-lobe cam and said rotary switch device consisting of a in number with the lobes on said earn, the brush of said commutator and said cam being mounted commutator, the segments of which are less in on the same shafts and being adapted to rotate number than the lobes of said cam, the brush of at the same speed, said magneto being of the said commutator and said cam being mounted polar inductor type the inductor bars of which on separate shafts which are operatively con nected together and with the magneto shaft so correspond in number with the lobes of said cam and the segments of said commutator. as to rotate at such synchronized speed that mak 11. An improved magneto ignition system for ing and breaking of the circuit by said contacts 60 is obtained whilst said brush is traversing each internal combustion and like engines comprising segment and the rotary elements of the magneto a magneto having primary and secondary wind ings forming an induction coil and a battery are also traversing the induction coil poles. 7. A magneto ignition system according to source of direct current wired in circuit with claim 1 wherein the circuit is common to both 65 said primary winding which consists of two sub of said sections of the primary winding and said stantially matched sections, a cam operated pair of relatively reciprocatory contacts, and a cir circuit changing means consists of a common cuit changing rotary switch device for making rotary switch device and said circuit maker and and breaking the battery circuit through each breaker means consists of a common pair of rela tively reciprocatory contacts having a condenser 70 of said sections alternately in such a manner associated therewith, said rotary switch device that the battery current flows ?rst in one direc consisting of a commutator the brush of which tion in one of said sections and thence in the is mounted on the magneto shaft and with said opposite direction in the other section to thereby contacts so that the brush and magneto shaft alternately reverse the battery current ?ux in may rotate at such synchronized speed as to 75 said induction coil, and means for synchronizing 2,612,886 the movements of said rotary switch and recipro catory contacts with the movements of the mag REFERENCES CITED neto shaft to thereby substantially match the re The following references are of record in the versing battery current ?ux in said induction ?le of this patent: . coil with the alternating magneto ?ux therein. UNITED‘STATES PATENTS 12. For use in a magneto ignition system ac 0 Number cording to claim 1, a magneto having a rotary Name Date switch device and a- pair of cam operable recipro 1,026,565 Cunningham ______May 14, 1912 catory contacts mounted thereon and which are 1,765,454 Schreil ______June 24, 1930 adapted to be wired in circuit with said two sec FOREIGN PATENTS tions of the primary winding of the induction coil Number Country Date of said magneto and are adapted to function as the battery circuit changing means and the cir 374,565 France ______Apr. 20, 1907 cuit maker and breaker means. ' 475,795 ‘ France ______June 14, 1915 ERIC GLEN MACKAY.