US1532799A - Magneto - Google Patents

Description

A ril 7, 1925.

P. BROWN ET AL MAGNETO Filed July 18, 1923 lNVENTOR ATTORNEYS Patented Apr. 7,1925.

UNITED STATES PATENT OFFICE.

rnanrs naowmmA-a naunmcxson. naaonn 1 1. CLARK, am) 'rnmmncn e. LOUIS,

.or sramermnn, uassacnusa'r'rs; SAID nnnnmcxson, cmmx, AND LOUIS assrenons TO wIco amc'rmc COMPANY, or wear srnmorrmn, massacnwsn'rrs,

A. CORPORATION OF MASSACHUSETTS.

memrro.

Application filed my a, 1923. Serial a... 852,352.

T all whom it may concern:

Be. it known that we, PHELPS BROWN, IRA

E. HENnnIoKsoN, HAROLD H. CLARK, and

TERRENCE G. Louis, citizens of the United 6 States, residing at Springfield, in the county of Hampden and State of l\[assachusetts, have invented new and useful Improvements in Magnetos, of which the following is a specification.

This invention relates to improvements in lnagnetos and is more particularly concerned with the actuating mechanism thereof. This invention is also an improvement on that disclosed in the copending application for U. S. Letters Patent filed by Phelps Brown and Ira E. Hendricksonon June 2, 1923 under Serial No. 643,037.

The general type of magneto. with which this invention is concerned, is that in which 20 an armature is moved substantially in a straight line path toward and away from,

and preferably into contact with magnetic poles. The general class of actuating mechanism to which this invention relates, is that wherein the driving spring (for moving the armature away from its poles) is first placed under stress for the armature driving function by mechanism operated by the engine but is incapable of moving the latter until the contact between the armature and poles has been broken, such contact being broken, after the driving spring has been stressed, by an inelastic transmission of force from engine operated parts, after which the driving spring comes into play and drives the armature away from its poles more rapidly than it would be otherwise driven by the engine.

One example of a magneto and an actuating mechanism of the class above defined will be found in the pending application for United States Letters Patent of Ira E. Hendrickson. Serial No. 504,334, filed September 30, 1921.

h'ijovement of the armature away from its poles.'in the manner and by the mechanism, above described, is important in that the spark is produced independent of engine speed and an intense spark is produced at cranking and low engine speeds. In certain cases. this sort of actuating mechanism is not so important when the engine is running at high speed and this invention is concerned with the provision of means whereby either form of operation may be accomplished, when and as desired.

The general object of the invention is to provide, in magneto actuating mechanism of the general. type defined, improved means for rendering the drive spring inoperative, when desired, and for driving the armature directly from the engine, as by an inelastic transmission of force therefrom.

Another object of the invention relates to an arrangement of parts for automatically rendering the drive spring inoperative, after the engine has been started.

A further object of the invention is to provide in magneto actuating mechanism of the general class described, means for automatically causing an advance in the ignition spark after the engine has been started.

Other objects and advantages relate to the particular construction and arrangement of parts and will more particularly appear in the following description andin the illustrative embodiment of the invention in the accompanying drawings, in which Fig. 1 is an end elevational view of a magneto embodying the invention;

Fig. 2 isa front elevational view thereof;

Fig. 3 is an enlarged fragmentary sectional plan view taken on the line 3-3 of Fig. 1;

Fig. 4 is an enlarged fragmentary front elevational view of a portion of Fig. 2;

Fig. 5 is a crosssectional view taken on the line 5-5 of Fig. 2;

Fig. 6 is a. fragmentary elevational view of a modification of the device shown in Fig. 3;

Fig. 7 is a fragmentary elevational view taken at right angles to Fig. 6; and

Fig. 8 is a diagrammatical View of the magneto proper.

In these drawings, there is shown, in full detail, an embodiment of the invention which incorporates many desirable features relating to the particular construction and arrangement of various parts, whichf'although important and preferred, are not necessarily essential in so far as the broader aspects of the invention, as above outlined are concerned. A's'to the broader aspects of the invention, the'showing is to be taken as an illustrative example of one of many embodiments of the invention.

The invention is not particularly conbut rather with improved actuating mechanism for a magneto of a given ty e. Accordingly the magneto structure as not been illustrated in detail and the general type of magnet-o, with which the invention is concerned, will suiiiciently appear from the diagrammatic showing in Fig. 8. The magneto is of the general type in which an ar mature, such as a, is moved in a substantially straight line path to and from, and preferably into and out of contact with magnetic pi es, such as the ends of the pair of cores I"). The latter are magnetically connected to e poles of suitable magnetic source, such is permanent magnet c. The electrical are preferably, although not necociated with the cores 6 and, as I ise a primary and a secondary coil t 6, respectively, on each core. The coils (Z and e are electrically connected, series, as illustrated, and the terminals he connected coils d are electrically conto relatively movable breaker points a condenser i1, being bridged across points, The terminals of the d coils e are suitably connected, as ed, to the ignition device, such as the im' I and 2, the ends of the cores To clear y appear and the armature a is shown in contact with them.

The breaker point f as shown in Fig. 2, is adjustably secured in the upper end of a stationary tube m. The movable breaker point {I is carried on the upper end ofa cylindrical member 71, which slides in tube m and guides the points i and 7 into square engagement. This member n also serves, by its weight or mass, which is considerable, to cause the points 7 and q to engage with a percussive blow, the effect of which is to slightly peen the engaged contact surfaces and keep them free from pits. The contact faces, by this arrangement, are, in effect, resurfaced at each operation and kept smooth, flat and bright. Attached to the member n is a stem 0 which extends freely through a bracket k fixed to armature a. A spring p encircles stem 0 and acts between the upper face of armature a and the lower face of member '21. Below bracket in an abutment q is adjustably mounted on stem 7). The points f and 9 en gage before the armature a engages cores b and the spring k permits continued movement of the armature. Thus, when armature a is seated on its poles b, the abutment is spaced from the bracket 7: whereby it is not immediately engaged and moved on the downward flight of the armature.

In magnetos of this type, the armature is periodically caused, to move rapidly away from its poles b and thus cause a substantial change in'the flux flowing in the magnetic circuit. The coils d are connected, by breakcomes into play to remove the armature from er points and g, in a closed electrical circuit at the time when the armature is in contact with its poles. These coils (Z function to prevent rapid changes in flux in the mag netic circuit and, m edect, hold the flu until the armature has moved a suihcient distance away from its poles to create a substantial air gap, at which time the breaker points are separated and an ignition current generated in coils e, The points and g are moved into contact e nears poles and vent any sudden ch occasionally a from tr. e g ne bracket as shown, all th also be 'sronorie actuat ecnanism may d, with the exception of the g cam 10, which is fixed to an endriven shaft, such as the cam shaft 5. The actuating mechanism embodies a resilient driving means for moving the armature away from its poles, herein shown as This spring is stressed at proper nter, s by a transmission or force from the as by the movement of eccent c but, even when fully stressed, ring is insufficient of it 7 1 to oven coil spring 11,

seir some the forces holding armature a to 95 poles. For overcoming such forces and starting the armature on its downward flight, a trippingdevice 12 is employed which after the spring 11 has been stressed itspoles by an inelastic transmission of force from engine operated parts, such as the eccentric 10. The actuating mechanism also includes suitable means for returning the armature to its poles, herein shown as including a coil spring 13. The force acting to hold the armature to its poles, as herein illustrated, is that due to magnetic attraction.

The actuating mechanism, as above broadly defined, is not a feature of the present invention but rather a definition of the general class of mechanism to which the invention is adapted. The invention, according to one feature, is characterized by the provision of means for rendering the drive spring inoperative when desired and, as to a second feature, of automatically efl'ecting with the above object an advance in timin The means for accomplishing both objects consists of a member 14 which is movable into position to cooperate with member 12 and prevent the preliminary stressing of the drive spring and cause the armature to be tripped, or started away from its poles, at an earlier timethan it otherwise would be.

The invention, in addition to the features above described, contemplates the provision of certain advantageous and desirable features, as improvements in armature actuatotally ing mechanism of the general class described, which features relate to the particular mechanism illustrated herein. As to the broader features of the invention, the details of the particular mechanism, described below, may be varied-within wide limits and still embody the invention. 1

In conjunction with the armature actuating mechanism'two arms 15 and 16 are piv mounted intermediate their ends on a common stud 17 carried by frame A. The drive spring 11 is mounted between the outer ends of these arms and tends to separate them. The tripping device 12 is adjustably secured to one of these arms, as 16, near the same end but in an offset location, as shown in Fig. 1. The return spring 13 acts between a suitable spring seat on the inner end of arm 16 and a stationary spring seat 18 is provided on frame A. The inner ends of both arms 15 and 16 lie between the spaced arms 19 of a fork 20 fixedly secured to the lower face of armature a. The inner ends of arms 15 and 16 overlie, respectively, a stud 9 fixed on and extending between arms 19. Thearm 16 is provided with an abutment 21 which is located inthe path of a cam follower 22, herein shown as a third arm pivoted coincidentally with the first and second arms 15 and 16 on the studll.

lhe abutment 21 is preferably adjustable, being in the nature of a cap screw threaded into arm 15, or a lug 23 thereon, and held in adjusted position by alock nut 24.

The tripping device 12 is also adjustably mounted, being in the nature of a cap screw threaded into arm 16 and held in adjusted position by a lock nut 26.

The spring 11 is also adjustable for its lower spring seat 27 is mounted on a screw 28, threaded into arm 16 and held in adj usted position by a lock nut 29. i

The device for rendering the drive spring 11 inoperative is formed as an integral portion of a lever 30 by bending over a portion thereof, as shown in Fig. 4. The lever 30 is pivotally held to arm 15 by a cap screw 31, as shown in Fig. 4. In order to rcleasably hold the lever 30 in either of the two positions which it may assume, arm 15 is provided with two pairs of recesses 32- and 33 in its lower face, as shown in Fig. 4. A circular disc 34. loosely encompassing the head of screw 31 and yieldingly urged upwardly by the spring 11, has a pair of upturned lugs 35. oppositely locatedthereon. These lugs 35 pass upwardly through recesses 36 in lever 30 (Fig. 3) and are adapted to enter either pair of recesses 32 or 33. When engaged in the former, as shown, the lever 30 "is so held that the device 14 is entirely out of the path of member 12 but when located in the recesses 33, the device 14 directly overlies the member 12.

The spacing means 14 accomplishes its "function manually but the function may be automatically accomplished by the mechanlsm shown in Figs, 6v and 7. As there shown, the s acing means consists of a cam 40 fitting within a suitable slot in arm 15 and pivotally mounted on a stud 41. A spring 42, acting between the head of stud 41 and one face of cam 40 tends to frictionally hold it in position. An operating handle 43, having a weighted outer end 44 is provided for moving cam 40. A stop 45 is provided on arm 15 to limit the upward swinging movement of arm 43 and, when the arm is positioned as shown in full lines in Fig. 6, the cam 40 does not extend below the lower face of arm 15. The spring 42 will hold the cam in this position (which is the starting position) until the engine has been started but after a few'strokes of the engine the vibration set up b the arrestat-ion of the armature will cause ever 43 to fall downwardly into the dotted line position in which the cam 40 projects below arm 15 for engagement by member 20. The cam 41 fc-rosses centers in moving to its dotted line 9 position and engages a wall 46 on arm 15 as a stop to limit its counterclockwise movement. Consequently, the cam cannot be moved in a clockwise direction-by member 12 and remains in the dotted line position, until manually moved.

The operation of the magneto will now be described. For starting the spacing members 14 or 40 are positioned out of the path of member 12. With the parts occupying the. relative positions illustrated, the cam 10.

will, on continued rotation engage and move follower 22 and the latter will be swung on its pivot 17 thereby engaging abutment 21 and moving arm 16. The time of such eugagement can be varied, as desired, by adjustment of the abutment. The left hand end of arm 16 is thus swung upwardly but the left hand end of arm 15, being held against upward movement, by the forces holding armature a to its poles b, is not immediately moved. During the relative movement of arms 15 and 16, the spring 11 is compressed for the subsequent armature driving function. It is to be noted that during the described movement of arm 16, its right hand end moves downwardly thereby drawing away from the armature (z and retracting the return spring 13, whereby a path is cleared for the downward flight of the armature.

After spring 11 has been fully stressed the member 12 has been moved into engagement with arm 15 and, on continued rotation of cam 10, the arm 15 is moved and armature a disengaged from its poles. This disengagement, it is to be noted, is effected by an inelastic transmission from the cam. The armature a. is, however,

manner for immediately on the creation of an air gap between the armatureand its poles, even though this air gap be very small, the armature SllPPOIi'. ing force of magnetic attraction is very much diminished and continues to diminish. at a very ra idl increasing rate, so that almost imme iate y the force of the stressed spring 11 becomes su erior to that of magnetic attraction and t 1e spring expands and moves armature a downwardly more rapidly than it would be moved by member 12. In other words the arm 15 is forced away from member 12 during the downward flight of the armature.

Continued rotation of the cam 10 eventually allows follower 22 to move radiall inward toward shaft S and thus arm 16 is allowed to move under the force of spring 13, whereby the armature is carried upwardly and a ain seated on its poles. The follower 22 is ree to move in one direction relatively to arm 16 and may move slightly away from arm 16. At such times the spring 13 functions also as a supporting force for armature a but this force, as has been described, is relaxed entirely during the stressing of. the drive spring so that magnetic attraction is the only armature supporting force functioning at that time.

The operation, thus far described, has been found useful and advantageous and it is particularly effective on starting or low engine speeds because the armature movement is efiected independently of, and at a higher speed than, engine speed. However, on higher speeds, a spark of even less intensity than that required for starting will suffice and, moreover, a more ra id armature s eed may then be imparted irectly from t e engine than at starting. In many cases, direct o eration of the armature from the engine uring its higher speeds is desired and to permit such operation, the member 14 is swung into overlying relation with member 12. This, as Wlll be evident from Fig. 1, will substantially prevent the stressing of spring 11 in the manner described and will cause the armature to be not only removed but moved during its entire down ward flight by an inelastic transmission of force from the cam. The two arms 15 and 16 do not then have any substantial relative movement on the downward flight of the armature and the latter is, as a practical matter, directly connected to t e engine. The return spring 13 functions, as formerly, to return the armature, th s being necessary in the embodiment illustrated, on account of the loose connection of follower 22 with arm 16. It will be-noted that the armature a is removed from its poles at an earlier point in the engine cycle than formerly, whereby the spark is automatically advanced as is desired for high speed running. Also'it is insured that the spark is retarded, as it should be for starting, for unless member 14 is moved to the illustrated position, only a small current will be produced which is rarely sufiicient for starting. Consequently, the operator is forced to move the member 14 to the illustrated position to cause the production of a sufficient spark to start the engine and, when member 14 is thus moved, the spark is automatically retarded.

As above alluded to, with the use of the cam 40 the drive spring 11 is automatically rendered ineffective after the engine has been started and the spark is, at the same time, auton'iatically advanced.

The particular contour of cam 10 and the manner in which it coacts with follower 22 are particularly important because of the resulting efi'ects obtained in the operation of the armature and the interrupter mechanism. The reater portion of the cam is concentric with shaft S and the rise portion thereof is formed by the two outward- 1y converging faces. 10. In the counterclockwise rotation of cam 10, one of these faces 10 will eventually move into parallel vfaces commence to move out of parallelism,

which results in movement of the follower. The movement of the latter is, however, very slow in the initial stages and later increases, becoming very rapid in its latter stages as the point of the cam nears its engagement with the follower. Continued rotation of cam 10 produces reverse motion of the follower and this motion is very fast in its initial stages and slows down near its final stage and gradually decreases to zero.

By this arrangement, the armature which, as has been noted, is held by magnetic attraction to its poles, is barely cracked from its poles by a slow movement and may be said to be pried off, as distinguished from a dislodgement due 'to a sudden blow. As a result, the removal of the armature is effected relatively quietly and without the shocks and jolts which would occur were the initial movement of follower 22 a ra id one. The breaking of the magnetic hol is the severest part of the operation and reto the heavy duty of removing the armature,

does not alter the timing of the spark for armature is moved into and out of contact speed applied to point g,'which, with the attached mass n, serves to cause oint g to engage point 1 percussively for t e pur ose of keeping them' clean, Hat and bright. After the engagement of the breaker points, thearmature moves at gradually decreasing speed for the purpose of seating the armature on its poles in a relatively uiet manner.

The invention has been (1180 osed herein, in an embodiment at present preferred, for

the purposes of illustration but the scope of the invention is defined by the appended claims rather than by the foregoing descrip: tion.

Claims: 1. In a magneto, of the type wherein an with magnetic poles, a pivoted arm engageable with the armature and adapted to move it away from its poles, a second pivoted arm carrying an abutment adapted to engage and I move the first arm, cam means adapted for operation from the engine, and a'follower' interposed between said means and the second arm.

2. In a magneto, of the type wherein an armature is moved into and out of contact with magnetic poles, a pivoted arm engage able with the armature and adapted to move it away from its poles, a cam adapted for operation from the engine; a cam follower, a member interposed between the follower and said arm, and an adjustable abutment interposed between said arm and member and carried by one thereof.

3. In a magneto, of thetype wherein an armature is moved into and out of contact with magnetic poles, a pivoted arm engageable with the armature and adapted to move it away from its poles, a cam adapted for operation from the engine, a cam follower, a member interposed beween the follower and said arm, and an adjustable abutment interposed between said follower and member and carried by one thereof.

'4. In a magneto, of the type wherein an armature is moved into and out of contact with magneticpoles, a pivoted arm engageable with the armature and adapted to move it away from its poles, a. cam adapted for operatlon from the engine, a cam follower, a member interposed between the'follower and said arm, and adjustable abutments carried'by said member one of which is adapted for engagement with said arm and the other with said follower.

.5. In a magneto, of the type wherein an armature is moved into and out of contact 1 with magnetic poles, two arms pivoted intermediate their ends and near one end said arms near operatively engaged with the armature to move it, in opposite, directions, an abutment carried by one of said arms near its other end adapted to engage the other arm, an actuating cam, and a ivoted arm engageable by the cam and a apted to engage and move one of thel first named arms near its ,oi the type wherein an .oved" into and out of con- "eticpoles, two arms pivoted nected intermediate their end operatively engaged tomove it in opposite tmenti carried by one of r. dlrectlons, a

gage the other rm, .an actuating cam, and a cam followerip voted coincidentally with the first'namedarms and adapted to engage one of thelatter near-its last named end.

7. In amagqew, of the type wherein an armature is'moved into and out, of contact with magneticpoles, two arms pivoted and pivotally-connected intermediate their ends and near one end operatively engaged with the armature to move it in dpposite directions, an abutment carried by one of said arms near its other end adapted to engage the other arm, a spring interposed between said arms adjacent said abutment, an actuating cam, and a pivoted arm engageab-le by the cam and adapted to engage and move one of the first named arms near its last named end. A

In a magneto, of the type wherein an armature is moved into and out of contact with magnetlc poles, two arms pivoted and 'pivotally connected intermediate their ends adapted to engage one of the latter near its last named end.

9. In a magneto, having two magnetic poles with which an armature is periodically engaged and disengaged to connect and disconnect the same, a pivoted lever having a part for engaging the armature and moving it away from said poles, a movable member, a spring tending to force said member against the armature and the latter toward its poles, and means adapted for connection to an engine for actuating-said lever and for moving said member away from the armature.

10. In a magneto, of the type in which an armature is moved into and out of contsotlierend adapted to env loo tact with magnetic poles, an arm pivoted intermediate its ends and having one end adaptedto move the armature away from its poles, a second arm ,pivoted intermediate its ends and having one end adapted to move the armature toward its poles, means carried by theother end of one of said arms adapted to engage the other arm and move the same, and means adapted for operation under the control of the engine for oscillating said arms.

11. In a magneto, of the type in which an armature is moved into and out of contact with ma etic poles, an arm pivoted intermediate 1ts ends and having oneend adapted to move the armatureaway from its poles, a second arm pivoted intermediate its ends and having one end adapted to move the armature toward its poles, means carried by the other end of one of said arms adapted to engage the other arm. and move the same, actuating means adapted for operation under the control of the engine, and a third pivoted arm interposed between such means and the second arm.

12. In a magneto, of the type in which an armature is moved into and out of con tact with magnetic poles, actuating mechanism for moving the armature to and from its poles including means whereby the armature may be moved away from its poles en.- ti rely by an inelastic transmission of force, said means constructed to remove the arm-1- ture from its poles gradually at a relatively slow rate and subsequently move the armature at relatively high speed.

13. In a magneto, of the type wherein the armature is held by magnetic attraction to its poles, mechanism whereby the armature may be moved away from its poles entirely by'an inelastic transmission of force and initially effective at a relatively slow speecl to pry the armature from its poles and subsequently effective to move the armature atrapidly increasing speed.

14. In a magneto, of the type wherein the armature is held by magnetic attraction to its poles, mechanism whereby the armature may be moved awayfrom' its poles entirely by an inelastic transmission of force and initially effective at a relatively slow speed to pry the armature from its poles and subsequently effective to move the armature at rapidly increasing speed, followed an armature is moved into and out of con-- tact with magnetic poles, a cam having a concentricdwell portion and two outwardly converging faces substantially tangential'to said dwell portion, and mechanism-connecting the cam and armature including a follower having a flat face which is adapted to be initially engaged by one of sald cam faces, the faces initially engaging in substantially parallel and contiguous relation.

17. In a magneto, of the type wherein the armature is held by magnetic attraction to its poles, mechanism whereby the armature may be moved away from its poles entirely by an inelastic transmission of force and initially effective at relatively slow speed to pry the armature from its poles and subsequently effective to move the armature at rapidly increasing speed, followed by a comparatively rapid initial return movement of the armature which gradually decreases in speed to seat the armature on its'poles relatively quietly, breaker point mechanism associated with the magneto and including cooperating and relatively movable breaker points, means "movable with the armature for disengaging them at an intermediate point in the'flight of the armature away from its poles and while the armature is moving at high speed and for engaging them at an intermediate point in the return flight of the armature and before the'final slow movement of the approach of the armature to its poles.

I11 testimony whereof we have aflixed our signatures.

PHELPS BROWN.

IRA E. HENDRICKSON. HAROLD H. CLARK. TERRENCE G. LOUIS.

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