US1734918A - Magneto - Google Patents

Description

Nov 5, 1929.

W. S. ROBINSON. JR

MAGNETO Filed Jan' 6, 1928 I5 Sheets-Sheet 57 INVENTOR.

$Zpi

ATTORNEYS.

NOV. 1929- w. s. ROBINSON, JR 1,734,918

MAGNETO Filed Jan. 6, 1,928 5 ShQQES-Sheet 2 Z: 2/ 0 nil Ii 20 j v 1 i I if! 1 J3 I Ex /f if 7 [I TTORNH Nov. 5, 1929.

W. S. ROBINSON, JR

MAGNETO Filed Jan. 1928 3 Sheets-Shea QQ. Ilg

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INVENTOR. zgzaj B r /Vwfl ATTORNEYS Patented Nov. 1929 UNITED STATES PATENT OFFICE WALTER S. ROBINSON, JR., OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO WICO ELECTRIC COMPANY, OF WEST SPRINGFIELD, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS MAGNETO Application filed January. 6 1928. Serial No. 244,981.

This invention relates to improvements in magnetos and is primarily directed to improved provisions for operating the breaker point mechanism. v a

5 The improvements of this invention are intended for use in a magneto of the type in which the armature may be actuated in either of two ways. That is, the armature may be driven directly by. means of aninelastic transmission from the drive shaft of the magneto or it may be driven by impulse mechanism, the operation of which is initiated by, or under the control of, the drive shaft but which, when once initiated, proceeds independently of the drive shaft. For example, the impulse mechanism includes a drive spring, which is placed under stress by I the drive shaft, but which is incapable of moving the armature until the latter has been tripped or started in its flight by an inelestlc transmission from the drive shaft. Once the I armature has been started in its flight, it is moved by the expansive action of the pre viously stressed spring at a speed independent of that of the drive shaft and entirely free from any control by the drive shaft.

In magnetos, of the particular character set forth, it has been the practice to open the breaker points directly from and by movement of the armature. That is, an abutment carried by the armature engages, at a predetermined point in the flight of the armature, with an abutment on the stem of the movable breaker point and causes separation of the breaker points after a predetermined degree of air gap has been established between the armature and its poles. This plan of operating the breaker points is considered the best and most reliable one for securing accuracy of timing, when the armature is driven b the impulse mechanism. On impulse drive, the armature is always moved at substantially constant speed and, under such conditions. there is always one point in the flight of the armature at which the breaker points should open to produce the best results. Therefore, since the position of the armature is the controlling factor, the armature should be made to control the opening of the breaker points. To control such opening directly from the drive shaft. as by a cam thereon, is not ordinarily feasible for impulse drive. Impulse drive 1s largely used for starting and the drive shaft may thus turn relatively slow, while the spring impulse, initiated by the slow moving drive shaft is relatively rapid. Thus, the flight of the armature, which is initiated at a periodic point in the revolution of the drive shaft would be completed under the spring impulse before the drive shaft could turn any appreciable increment ahead of said predetermined point, as would be necessary in order to operate the breaker points after the armature has left its poles. Also, it is diflicult to secure exact uniformity in the impulse springs and therefore difi'erent springs might move the armature at somewhat different speeds. There would thus be a chance for error if the timing on impulse drive were controlled from the drive shaft-even though this were otherwise feasible. Therefore, this invention follows the plan of operating the breaker points directly from the armature, when it is being driven by the impulse mechanism, as being the most reliable means of securing accuracy in timing on impulse drive.

On direct drive, the armature moves proportionately to the drive shaft and recision in timing under such conditions is est insured if the breaker points are operated directly from the drive shaft rather than from the armature. Theoretically, it should make no difference for the armature, as has been said, is moved proportionately-thereto but there are arts interposed between the armature and rive shaft which may, under certain conditions, cause inaccuracies in timin By operating the breaker points directly from the drive shaft, the aforesaid interposed partsare eliminated so far as exerting any influence on accuracy of timing is.

concerned. Moreover, on direct drive the speed of armature movement is variable and it does not necessarily follow that the breaker points should be opened always at the same predetermined point in the fiight'of the armature. Variation in armature speeds may mean that the breaker points should open at various points in said flight, where fore control of the breaker points directly from the armature is no longer essential.

Furthermore, one must make provisions for- Preferably, although not necessarily, the

selection of the breaker point actuating means is made automatic and dependent on the shifting from one form of armature drive to another. For example, on impulse drive of the armature, the breaker points would be controlled directly from the armature but, when a shift is made from impulse to direct drive, the breaker point actuating means would be shifted so that the breaker points would then be controlled directly from the drive shaft of the magneto.

More particularly, it is an object of the invention to provide the two types of breaker point actuating means and to provide means for bodily displacing the breaker point mechanism to bring one or the other of said means into effective action.

These and other objects will appear in the following description and be particularly pointed out in the appended claims.

The invention will be disclosed with reference to the accompanying drawings, in which Figs. '1 and 2 are front and end elevational views, respectively, of a magneto embodying my invention; up

Fig. 3 is a sectional elevational view taken on the line 3-3 of Fig. 2 and drawn to a larger scale;

Fig. 4 is a cross sectional view taken on the line 4- 4: of Fig. l;

Fig. 5 is an enlarged view of the interrupter mechanism, showing parts thereof in different relative positions than obtain in Fig. 6 is a sectional plan view taken on the line 6-6 of Fig. 5;

Fig. 7 is a diagrammatical view illustrative of the electrical connections;

Figs. 8 and 9 are cross sectional and longitudinal sectional views, respectively, of the magneto, showing another form of the invention; and

Figs. 10 and 11 are sectional plan views taken, respectively, on the line 1010 of Fig. 9 andthe line 1111 of Fig. 8.

In these drawings, I have shown two embodiments of my invention and, in each case, the invention has been illustrated in connection with the same type of magneto. The magneto chosen as a background for this invention, is of the two unit type, having two reciprocating armatures and arranged so that each unit contributes to and assists in the work performed by the other. This type of magneto has been selected as best calculated to show all of the advantages of my invention. Atthe same time, many of the advantages of my invention are not dependent on a magneto of the two unit type nor on a magneto of the particular character and description illustrated. Therefore, the invention, except as pointed out in the appended claims, is independent of the magneto construction.

Referring first to the construction ofthe magneto, used herein to exemplify both forms-of the invention, it includes a bed plate 11 (Fig. 1) and a frame 12 of nonmagnetic material, which is supported from, above and in parallel relation with the bed plate, as by an end frame 13 and a leg 14. Rotatably mounted in bearings provided in the end frame 13 and leg 14 is a drive shaft 15 (Fig. 3), adapted to be driven from an internal combustion engine. The parts, thus far described,- are common to both units of the magneto. These two units also utilize a common source of magnetic flux, consisting as shown in Fig. 2, of three banks of permanent magnets 16,-such banks being arranged side by side and each consisting of a vertical series of four bar magnets. Otherwise, the two units are structurally alike. A description of one will therefore suffice for both and corresponding parts of the second unit will be given the same reference numerals primed.

Each unit includes a pair of verticallydisposed and laterally-spaced laminated cores 17 (Fig. 1), the upper ends of which are connected to opposite polar extremities of the magnetic source. These upper ends areshaped to afford a recess to receive one end of a bank of magnets 16 and the magnets are held in this recess, as by wedges 18, which are driven in between a pair of adjacent magnets of the bank. The space between the upper ends of the cores 17 and 17 is filled with other laminations 19 (Fig. 2) which similarly afiord recesses to receive the polar extremities of the middle bank of magnets. The laminations of cores 17 and 17 and the laminations 19 are suitably clamped together as by a series of bolts 20 (Figs. 1 and 4) which also act to secure in place a nonmagnetic cross bar 21 which serves to tie the upper ends of the cores together and hold them in proper laterally spaced relation. The lower ends of cores 17 are received in recesses formed in a side edge of frame 12 (Fig. 1) and are clampedtherein by screws 22. These cores extend downwardly a short distance below frame 12 and'their bottom faces constitute magnetic pole pieces which are adapted to be intermittently connected and disconnected by a reciprocating armature 23.

Each unit also includes two primary coils 24, one encompassing each core 17, and two secondary coils 25, one encompassing each coil 24-. These coils and the corresponding coils of the other unit are housed in a common block B of bakelite, or other suitable material, which block fits snugly between frame 12 and the crossbars 21. The primary coils 24 may be connected in any suitable way to function as one choke winding. As shown in Fig. 7, they are connected in series by a wire 26. The two choke windings, comprising the connected coils 24 and the connected coils 24, are arranged in multiple and also in bucking relationship. One terminal of each choke winding is grounded and the other terminalis connected by a wire 27 to the insulated breaker point 28 of an interrupter mechanism to be later described. The other and cooperating breaker point 29 of such mechanism is grounded. A condenser 30 is bridged across the breaker points in the-usual manner.

The secondary coils 25, which together form the generating winding, are suitably connected, as in series, by a wire 31. The two generating windings, comprising the connected coils 25 and the connected coils 25', are connected in any suitable way so that the electromotive forces simultaneously produced in'each are merged. As shown, the two generating windings are connected in series by a wire 32 so that the two electromotive forces, simultaneously produced under the control of the one interrupter mechanism, are added. The terminals of the generating winding, represented herein by the wires 33 and 34 may be connected in any suitable or desired way for the utilization of the electromotive forces produced, as to a suitable distributor, such as has been indicated in conventional form at D and acts to successively connect the generating winding at properly timed intervals to a series of spark plugs 8.

Referring now-to the mechanism for reciprocatingthe armature 23 from drive shaft 15, the armature is fixed by bolts 35 (Fig. 3 to a lever 36. This lever and the correspon ing lever 36, is pivotally supported at one end on a stud 37, which is fixed to the described post 14. These levers extend from their pivotal supports along the inner and adjacent faces of their armatures .in spaced parallel relation and also extend beyond the armatures, having their forward ends offset outwardly (Fig. 8). The free ends of these levers terminate with cylindrical ends 38' and 38" (Figs. 3 and 4) which are disposed in parallel relation and adjacent end frame 13. The cylindrical end 38 (Fig. 4) pivotall'y supports a cross lever 39 at a point centrally between its'ends. The inner end of this lever underlies drive shaft 15 and is adapted to be moved downwardly by a cam 40, fixed thereon. A cam follower, in the shape of an arcuate flange 41, formed on a lever 42, 15 interposed between lever 39- and cam 40. The

levers 42 and 42 are pivoted at 43 and 43, the former to frame 13 (Fig. 1) and the latter to a lug 44 (Figs. 3 and 4) depending from frame 12. The outer end of lever 39 bears against the bottom face of a fulcrum pin 45 (Fig. 4), which is mounted for vertical sliding movement in frame 12 and may be held stationary in the illustrated position by a cam 46. The cams 46 and 46' are fixed to a common shaft 47 supported by and above frame 12 and extending crosswise thereof. As shaft 15 turns, cam 40 will engage cam follower 41 and through it, the inner end of lever 39. The outer end of lever 39 being engaged with the fulcrum pin 45, which as shown is held from rising above the illustrated position, it follows that the lever functions as one of the second class and through the end 38 moves lever 36 and thus armature 23 downwardly. A spring 48, interposed between bed plate 11 and armature 23 tends to move the latter upwardly and thereby causes the lever 39 to press its cam follower 41 against cam 40.

The action just described, is that which obtains on direct drive, i. e., when the armature is driven in its flight away from the polar faces of cores 17 entirely by an inelastic transmission from drive shaft 15. The two armatures 23 and 23 move up and down, substantially in alternation, and at speeds dependent on that of the drive shaft 15. For slow drive shaft speeds, as for example on cranking speeds, it is desirable to move the armature more rapidly than it could be moved by the drive shaft. For such purpose, an impulse mechanism is provided, the action of which is controlled and initiated by the drive shaftbut, when once initiated, proceeds independently of the drive shaft.

The impulse mechanism includes a drive spring 50 which is disposed alongside and par allel with the fulcrum pin 45 and like the lat ter also engages the outer. end of lever 39.

Spring 50 is interposed between this lever and a stationary abutment 51 fixed to a screw 52, by means of which the abutment is adjustably supported from a plate 53. This plate is fixed to an upstanding lug 54 by a screw 55 which passes through a spacing sleeve 56 interposed between the lug and plate. The lugs 54 and 54' are recessed to form bearings for the lower half of shaft 47. The screw 55 and.

plate 53 are dis sed rearwardly of shaft 47. In front of sha t 47 and threaded into lug 54 is a screw 57, which passes through the forward end of a late 58 and the head of which bears against t e plate. The plate 58 crosses shaft 47 and-overlies the same. The other end of plate 58 underlies and bears against plate 53, which forms a fulcrum therefor.

Thus, by tightening screw 57, plate 58 may be forced against shaft 47 to frictionally hold it in the various positions to which it may be moved. A lever 59 is fixed to shaft 47 as a means for turning the same.

To bring the impulse drive into play, lever 59 is turned clockwise from the position shown in Fig. 1 so that the cams 46 and 46 will allow the fulcrum pins 45 and 45 to rise. The described position of these cams is shown in Fig. 9. This changes the action of lever 39 from one of the second class to one of the first class during the initial part of the down ward movement of the lever by cam 40. That is, as cam 10 (Fig. 4) moves the inner end of lever 39 downwardly, the outer end thereof is free to rise and does rise, turning on the part 38 as a fulcrum. The raising of the outer end of lever 39 compresses spring 50 and this action continues until the lever 39 rises high enough to force the fulcrum .pin 45'against cam 46. The ,drive spring is thus placed under stress for the driving function subsequently to be performed. This spring, however, even when stressed to the maximum degree permitted by the illustrated arrangement, is not powerful enough .to move the armature 23 out of contact with the cores 17, to which it is firmly held by magnetic attraction. However, when the stressing of the drive spring is completed, the lever 39 will have lifted the fulcrum pin 45 into abutment with cam 16, which prevents further lifting of the outer end of lever 39. The action, which then momentarily ensues, is as described in connection with direct drive. That is, the cam 40 acts on the inner end of lever 39, the lever fulcrums at its outer end, and the armature is pried off its poles by "an inelastic transmission. Such action is only momentary, however, for as soon as a very small arr gap has been created between ,the'

armature and its poles, the force due to magnetic pull is so diminished as to be inferior to that of the stressed drive spring. Accordingly, such spring expands and moves the armature downwardly, the inner end of the lever 39 bearing on cam 40 as a-fulcrum.

Referring now to the interrupter inechanism, one form thereof is shown in Figs. 1, 2, 3, 5, and 6 and another form in Figs. 8 and 9. The two forms vary considerably in detail but each embodies the same and the essential feature of my. invention, which consists in the provisions of alternative. means for separating the breaker points 28 and 29, one of said means ,acting directly from the drive shaft and the other from the armature;- together with means for shifting from one means to the other. The particular details of the interrupter construction are therefore not essential and may bev varied as desired.

Referring to Figs. 1 and 2, a plate 60 is secured in upstanding relation at one end of the magneto, being secured by screws 61, some and closely adjacent relation.

of which thread into the frame 12 and the others into bed plate 11. Plate 11 serves as a support for the cylindrical casing 62 of the interrupter, the latter being secured by screws 63 to angles 64, which in turn are suitably attached to the plate. The casing 62 has an inwardly turned annular flange 65 (Figs. 5 and 6), which abuts plate 11. Rotatable in casing 62 and held from axial movement between flange 65 and the inwardly projecting ends of screws 63 and other similar screws 66, is a disc 67, which is circular except for a deep radially-disposed recess 68. An arm 69, secured to plate 67, extends through a slot in the upper peripheral portion of casing ,62, whereby the plate may be turned. The breaker point 28 is adjustably secured to a bracket which in turn is secured to and insulated from plate 67. The other breaker point 29 is secured to one arm of a wishbone-like member 71 which is pivoted'to plate 67 at 72 at a point near the junction of the two arms of said member. A spring 73 tends to hold the breaker points in engagement. The two arms of the wishbone-like member 71 straddle a cam 7 3, which is fixed to the drive shaft 15 and is capable, during each half revolution thereof, of engaging the part 74 of member 71 and moving the same to separate the breaker points.

The cam 7 3, however, is effective to do the described work only when plate 67 is positioned otherwise than in Fig. 5, as for example .when positioned as in Fig. 2 or in positions intermediate the extreme positions shown in Figs. 2 and 5. When plate 67 is positioned as shown in Fig. 5, the breaker points are separated by means carried by the armatures 23and 23. Such means comprise plates 76 ,and 76 (Fig. 6), which are fixed to their respective armatures by one each of the described pairs-of bolts 35 and 35' and which extend between post 14 and the hubs of levers 36-and 36'. These plates then turn at right angles and extend toward each other until they nearly meet,-when they again turn at right angles and extend outwardly in parallel The plates 76 and 7 6 terminate with fingers 77 and 77 which, when plate 67 is positioned as shown in Fig. 5, underlie a part 78 at the extremity of the lower arm .of the wishbone-like member 71. PlateGO has anopening 79 therein (Fig. 6) which is large enough to permit plates 76 and 76 as well as shaft 15 to freely pass therethrough. The recess 68 in late 67 is such as to permit shaft 15 and p ates 76 and 7 6 to pass therethrough and also such as to permit plate 67 to be moved throughout the described range without interference with the plates 76 and 76 (compare Figs. 2 and 5).

The fingers 77 and 77 of plates 76 and 7 6' move upwardly when their armatures move downwardly. These fingers move alternately so that first one and then the other engages the part 78 and moves it to separate the breaker points 28 and 29. As shown in Fig. 5, the finger 77' has been raised by its armature 23 and has caused the separation of the breaker points by moving the member 71 before cam 73 reached the part 74. Now, if lever 69 is moved to the right enough to carry part 78 out of the path of fingers 77 and 77, the breaker points will be separated by the action of cam 73" on the part 74 because the fingers 77 and 77 cannot rise high enough to engage any part of the lower arm of member 71 other than the part 78. The timing of the spark on direct drive can be varied by moving lever 69 over a certain part of its range, viz, from the position shown in Fig. 2 towards the left and up'to the point where part 78 swings into the path of fingers 77 and 77'. By moving lever 69 to the left, as viewed in Fig. 2, the spark will be retarded.

When lever 59 is set in position for direct drive, lever 69 should occupy the position shown in Fig. 2 for full advance tim ing. WVhen, however, lever 59 is turned in a clockwise direction far enough to move cams 46 into position for impulse drive, lever 69 should occupy the position shown in Fig. 5. In so far as is shown herein, both levers 59 and 69 are adapted for manual actuation. They may, however, be interconnected so that only one of the levers needs to vbe'actuated and so that the shift from one form of drive to another will automatically move the breaker point mechanism to efiect the shift to the proper form of breaker point actuating means.

The arrangement, just referred to,- is illustrated in connection with a second form of the plates 53 and 53' are connected together by an integral part 80 which serves as a support. for part of the interrupter mechanism. The support 80 has suitably and centrally fixed therein a hollow bushing 81 havmg a flange 82 at its lower end between which andthe bottom face of support 80, a Washer 83 is clamped. The hollow bushing 81 slldably receives a cylindrical shell 84, which is closed at its upper end and provided with a flange 85. A spring 86, secured at its ends by screws and 55 to support 80, has its central portion coiled around casing 84 and the flange 85 rests on such coiled portion. The breaker point 28 is adjustably supported in, and 1 nsulated from, the closed upper end of casin 84 and the mating breaker point 29 s fixe to the upper end of a plunger 87, which is mounted to slide in tube 84. The lower end of lunger 87 is connected to a member 88 which is of hollow rectangular form and en-' com asses drive shaft 15 together with a brea er point actuating cam 89, fixed thereon.

Fixed to and depending centrally from the This interrupter mechanism is'bodily shiftable by a cam 94, fixed centrally to the shaft 47, on the ends of which the cams 46 are mounted. Cam 94 acts on a rocker 95, which is pivotally supported intermediate its ends on a pivot pin 96, fixed at its ends to a pair of ears 97, integral with and depending from washer 83. The inner end of rocker 95 (Fig. 10) bears on a circumferential flange 98 formed on the lower end of breaker point casing 84. When shaft 47 is turned to bring cams 46- into position for impulse drive, cam 94 is moved so as to lift the outer end of rocker 95 as far as possible, thereby lowering the inner end of the rocker and moving casing 84 downwardly as far as possible. In Figs. 8 and 9, the parts are shown in the positions which they occupy on impulse drive. Casing 84 has been lowered, thereby deflecting spring 86 and also moving the breaker point 28, together with the parts connected therewith, downwardly. Thus, the entire interrupter is bodily shiftable, being positively lowered by cam 94 and being raised, as and when permitted by this cam, by springs 86 and 93. By turning shaft 47 in a counterclockwise direction from the illustrated posi-' tion, cam 94 is so moved as to allow the interrupter mechanism to rise, the limit of rising movement being reached when the outer end of rocker 95 bears on shaft 47 At this time cams 46 will have been moved about ninety degrees so that direct drive with full spark advance results. Cam 94 is so constructed as to permit some raising and lowering of casing 84 during direct drive, i. e., while the hi h and concentric portion of cams 46 bear on t o fulcrum pins 45.

The raising and lowering of theinterrupter mechanism is made to effect the shift from one form of breaker point actuating means to another. These actuating means comprise the cam 89, which is adapted to engage the lower horizontal side of member 88 when and after the interrupter mechanism is raised to a certain degree, and a pair of plates 99 and bolts 35 and 35' and extend forwardly beyond the armatures, terminating with horizontal ears 100 and 100'. These ears extend toward one another and terminate with edges when depressed, will engage the abutment and effect separation of the breaker points. With the parts positioned for impulse drive, as shown, member 88 has been lowered beyond the range, in which it can be engaged and depressed by cam 89. Therefore, as the armatures 23 and 23 alternately move downward, the nut 91 will be engaged, and depressed and the breaker points separated, first by one and then by the other of the ears 100 and 100. Now, if cam 94 is turned far enough in a counterclockwise direction from the position shown in Fig. 9, it will allow the interrupter mechanism to rise. As shown, such rising will be permitted as soon as one end of the high dwell portion of each cam 46 is swung over itsfglcrum pin 45, and thus into direct drive position, and the rising can continue while these dwell portions of cams 46 swing still further in the described direction, finally reaching a maximum when the other end of each dwell portion is brought over its fulcrum pin 45. As will be seen from Fig. 8, a slight raising of member 88 will allow cam 89 to act thereon and separate the breaker points and further raising of this member will cause separation of the breaker points at an earlier point in the revolution of shaft 15. The arrangement is such that when member 88 is raised as high as possible, i. e., until the lower horizontal side thereof is engaged with one of the two lowest points of cam 89, the abutment 91 still lies clear of and below the plates 100 and 100.

Thus, the invention affords two types of means for actuating the breaker point mechanism, one type of means being best adapted to do the work when the magneto is bein driven by the impulse mechanism and the other best adapted for the work when the. magneto is driven directly from the drive shaft andw1thout resort to the im ulse mechanism. The merits of the Ian 0 operating the breaker points from t e armature, when the latter is driven by the impulse spring have been set forth above. It is the best way now known in which to secure accuracy. With direct drive, where very much higher speeds obtain and where the speeds may vary widely, precision in timing is insured if the breaker pomts are operated directly from the drive shaft and it is easier to provide satisfactory means for effecting variations in the timing of the spark. If the breaker points were operated from the armature, when the latter is operated. by direct drive, the parts interposed be tween cams 40 and the armature introduce possibilities for errors. Particularly, care would have to be exercised to get the sparks to occur symmetrically, i. e.,'180 degrees apart in this case. This result can and has been accomplished in the particular magneto shown but the result is more easily and more surely accom .lished if the breaker points are controlled directly from the drive shaft. Also,

unequal wear in the chain of parts, .which function in theinelastic transmission from the drive shaft to the armatures, might throw the armatures out of exact balanced relation even though they were originally in such relation. That is, the two armatures might not start away from their poles in exact alternation even though originally so adjusted. This would not seriously afi'eet the functioning of the magneto but it would introduce an undesired irregularity in the timing of the sparks by causing them to occur at non-' symmetrical points in the revolution of the drive shaft. Therefore, the actuation of the breaker points is effected directly from the drive shaft.

The invention has been disclosed herein for illustrative purposes but the scope of the invention is defined by the appended claims rather than by the foregoing description.

What I claim is:

1. The combination with the armature of 4 a magneto and the drive shaft from which movement of. the armature is effected, of breaker point mechanism including cooperating and relatively movable breaker points, means carried by the armature and operable when said mechanism and means are positioned in a certain relationship to periodically separate the breaker points, means on said drive shaft operable-when said mechanism and first named means are positioned in another relationship to periodically separate said breaker points, and means for effecting a relative displacement between both said means and said mechanism to elfect one or the other of the aforesaid relationships and cause the breaker points to be separated by either the first-named or the second-named means.

2; The combination with the armature of a magneto and the drive shaft from which movement of the armature is effected, of breaker point mechanism bodily movable throughout a certain range, breaker point actuating means carried by the armature and operable when said mechanism is positioned within certain limits of said range, breaker point actuating means on said drive shaft operable when said mechanism is positioned within other limits in said range, and means for moving said mechanism through each of said limits and from one to the other.

8. In a magneto of the type wherein the armature maybe actuated either entirel by an inelastic transmission from the di'ive shaft or by impulse means the action of which is initiated by an inelastic transmission from said shaft, breaker point mechanism, two actuating mea'ns therefor either one of which may be rendered effective to operate said mechanism, one of said actuating means adapted for use when the armature is driven entirely by said inelastic transmission and initiated by an inelastic transmission fromsaid shaft, breaker point mechanism including cooperating and relatively movable breaker points, means carried bythe armature adapted periodically to separate said points when the armature is driven by said impulse means, said mechanism being bodily displaceable relative'to, said actuating means and movable over a certain range in which said actuating means is ineffective to separate said breaker points, means on said drive shaft eifective only when said mechanism lies within said range to periodically separate said breaker points when the armature is driven solely by said inelastic transmission, and means for bodily moving said mechanism to bring one or the other of said actuating means into action. I

5. In a magneto of the type wherein the armature may be actuated either entirely by an inelastic transmission from the drive shaft or by impulse means the action of which is initiated by an inelastic transmission from said shaft, breaker point mechanism including cooperating and relatively movable breaker points, ineans carried by the armature adapted periodically to separate said points when the armature is driven by said impulse means. said mechanism being bodily displaceable relative to said actuating means and movable over a certain range. in which said actuating means is ineffective to separate said breaker points, means on said drive shaft efi'ective only when said mechanism lies within said range to periodically separate said breaker points when the armature is driven solely by said inelastic transmission, and means for bodily moving said mechanism to bring one or the other of said actuating means into action and for securing variation of the time of separation of said breaker points. 7

6. In a magneto of the type wherein the armature may be actuated either entirely by an inelastic transmission from the drive shaft or by impulse means the action of which is initiated by an inelastic transmission from said shaft, breaker point mechanism bodily movable throughout a certain range, breaker point actuating means carried by the armature and operable when said mechanism is positioned within certain limits of said range, breaker pointactuating means on said drive shaft operable when'said mechanism is positioned within other limits in said range, and means for shifting the armature driving means from oneform of drive to the other and at the same time shifting said mechanism so that it lies within the first named limits when the armature is being driven by said impulse means and so that it lies within the last named limits when the armature is being driven solely by said inelastic transmission.

'Z. In a magneto of the type wherein the armature may be actuated either entirely by an inelastic transmission from the drive shaft or by impulse means the action of which is initiated by' an inelastic transmission from said shaft, breaker point mechanism bodily movable throughout a certain range, breaker point actuating means carried by the armature and operable when said mechanism. is positioned within certain limits of said range, breaker point actuating means on said drive shaft operable when said mechanism is positioned within other limits in said range, and means for shifting the armature driving means from one form of drive to the other and at the same time shifting said 'mechanism so that it lies within the first named limits when the armature is being driven by said impulse means and so that it lies within the last named limits when the armature is being driven solely by said inelastic transmission, said shifting means also operable to move said mechanism within the last named limits to advance or retard the time ofseparation of the breaker points when the armature is being driven solely by said inelastic transmission. I

In testimony whereof I have affixed my signature.

WALTER s. ROBINSON, JR.

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