US2420169A - Magneto - Google Patents

Description

May 6, 1947. c, DOLS 2,420,169

MAGNETO Filed Oct. 19 4 Sheets-Sheet 1 FIZZ-3-1.

3mm Cannes (1. DOLS May 6, 1947. c. G. DOLS 2,420,169

MAGNETO Filed-Oct. s, 1945 4 Sheets-Sheet? awe/Mm CHmm-s G. Dow

May 6, 1947. c. G. DOLS 2,420,169

MAGNETO Filed Oct. 5,. 1945 4- Sheets-Sheet I5 Camus G. Doua 334 QMLM+W- y 5, 1947- cps. DOLS -2,420,169

MAGNETO Filed 001;. 3, 1945 4 Sheets-Sheet 4 Cannes G. Dops Patented May 6, 1947 UNITED STATES PATENT OFFICE MAGNETO Charles G. Dols, Long Beach, Calif., assignor to D. W. Onan & Sons, Minneapolis, Minn., a partnership composed of C. W. Onan and R. D.

Onan

Application October 3, 1945, Serial No. 619,990

6 Claims.

This invention relates to improvements in magnetos for ignition in internal combustion engines.

The primary object of my invention is to provide an impulse magneto for this purpose which may be arranged in a space in the engine otherwise unoccupied by any useful parts. In the type or engine here in mind there is employed a flywheel which also may carry fins to act as a blower for cooling the engine, and this member which, of course, rotates with the engine crankshaft, has an interior hollow or chamber in which the magneto of my invention may be advantageously arranged to thus make use of otherwise wasted s ace. It is thus further unnecessary to arrange the magneto outside or upon the engine housing, where it occupies added space, or to use a chain, belt or other suitable means for connecting the magneto to the engine.

Another object of my invention is to provide a magneto of simple, inexpensive and durable and troublefree construction.

These and other more detailed and specific objects will be disclosed in the course of the following specification, reference being had to the accompanying drawings, in which Fig. 1 is a frontal elevation of the flywheelblower unit of an engine partially broken away to show parts of the magneto arranged interiorly thereof.

I Fig. 2 is an enlarged vertical sectional view, taken substantially along the line 2-2 in Fig. l and showing associated parts of the engine itself.

Fig. 3 is a sectional View along the line 3-3 in Fig. 2 showing the magneto at the point of starting its stroke or movement as the engine is cranked.

Fig. 4 is a detailed perspective view of the dog or pawl for operating the magneto.

Fig. 5 is a view similar to Fig. 3 but showing the magneto at the point of its operating or firing stroke or movement.

Fig, 6 is a diagrammatical View illustrating the wiring of the magneto and associated ignition system elements.

Referring now more particularly and by refer ence characters to the drawing, I show therein a fixed or rigid part A with which is associated a flywheel-blower member 13. The two cooperate to form a hollow or chamber C, interiorly of the member B, wherein the magneto D of my invention is located.

In the particular case here shown the fixed part A is a gear casing which is attached to and. forms a part of an internal combustion engine, one side wall of which is indicated t E, Theengine includes a crankshaft it one end of which extends out through the part A and into a hub II on the member B, said hub being secured a by the key l2 and cap screw is to this shaft to turn therewith. The shaft extends through an oil seal M located within a short cylindrical neck [5 formed on the part A. A crank dog it, for attachment of a hand crank (not shown) is provided for cranking the engine and in addition the end face of the member B is provided with a rope groove I! for the use of a starting rope, if preferred.

Further, as here shown, the rotating member B takes the form of a blower having fins E3 on its outer peripheral surface, which operate inside a hood is secured at 29 to the engine, and blow air inwardly over the engine for cooling the same. The member B may also be a flywheel for the engine, of course.

The magneto D is of the impulse type, being first movable through a forward, or energy storing stroke as the engine is cranked, and then movable back through a working stroke to deliver a surge potential for ignition. It will be noted that the magneto is located in its entirety in the space C and this is a space which is ordinarily wasted, or contains no vital part of the engine. I thus, by my invention, achieve a degree of compactness or streamlining of the engine as wel1 as a simplification thereof, particularly of the driving means for the magneto.

Turning now to the construction of the magneto itself, it comprises a back or carrier plate 2|, or movable support member, which is substantially circular in shape and of a diameter substantially less than that of the recess C. At its center the carrier plate 25, as it will be here inafter called, has an opening 22 which clears the hub l l and a bearing collar or hub 23 extends from the plate to fit over and journal upon the bearing neck [5, of the gear case or part A. The plate 2! is thus supported for movement about the same axis as the member B. Such movement is, however, limited in magnitude by arcuate slots 24 formed through the plate 2i and by stop pins 25 which are secured to the part A and extend therefrom through said slots. The carrier plate is thus arranged for limited oscillating movements with respect to the part A and the plate is biased in one direction by a spiral spring 26 which is positioned around the hub 23 and secured at one end at ll thereto and secured at its other end at 28 to part A. The movement of the carrier plate, under influence of the spring v26, is fin the direction of the direction arrow F in Fig. 5 and the normal position of the plate is that shown in Fig. 3. It may here be noted that this direction F, in which the carrier plate is biased by the spring 25, is opposite to the direction in which the crankshaft iii and member B rotate in operation, as indicated by the direction arrow G throughout the drawing.

The carrier plate 2! is moved, through the range permitted by the length of the slots 24, in the direction G as the engine is cranked, and for this purpose I provide a detent or dog 29 which is pivotally mounted upon a pin 38 carried by the member B and located in the recess C. The location of the dog 29 is further such that at one point in its travel with the member B as the engine is cranked it may engage a catch or finger 3! which is secured at 32 to and extends radially from the carrier plate 2! and when the dog is thus engaged it will be apparent that the plate will travel with member B. The dog 2Q is biased to swing at its free or working end toward the peripheral edge of the carrier plate by a torsional coil spring 33 arranged in well known manner and as the dog travels around the plate it will thus meet and remain in engagement with the catch 3!. When the carrier plate 2! has been moved in direction G a distance substantially that permitted by the slots 24, however, the dog 29 will be disengaged from the catch 3! by action of an angular face 34 on the dog which engages a release or knock-out pin 35 secured to part A and lying in the path of the dog. (See Fig. 5). This face 34 will then cam the dog 29 outward until it releases the catch 3! and continued movement of the member B as the engine turns on over will have no further efiect on the carrier plate until the dog reengages the catch. Of course, as the dog thus clears, the carrier plate 2! will be snapped back in direction F by action of the spring 26 and will return to the position of Fig. 8 which may be termed the starting position. The edge of the carrier plate is cut away or reduced in diameter as indicated at 36, to clear the pin 35. The cut away 35 further guides the dog 29 into engagement with the catch 3!, it being of course understood that the dog rides the remaining circular edge of the plate until it reaches said cut away 36.

A laminated core piece or member 3'! is secured, as indicated at 38, upon the carrier plate 2! and comprises a T-shaped head portion 39 which extends radially with respect to the plate and has an outer arcuate edge lying substantially flush with the periphery of that plate. The magn to coil is formed by a winding indicated at '26 secured around the shank of the T-shaped portion 35 of the core piece and one terminal of the winding is grounded to the core piece and to the frame in general, as indicated, by the conductor 55. An opening is provided in the plate 2! to clear the coil. The other terminal of the winding 43 is provided with a conductor 42 which leads to an interrupter, indicated generally at 43, comprising a base 44 secured by screws 6-5 to the carrier plate and provided with an up-turned end 45 upon which is a terminal screw 4i insulated from the metal parts by insulating washers 43. The aforesaid conductor 32 is electrically connected to the terminal screw 3?, as indicated at 42. Oscillatably mounted upon the base id is a rocker member .9 pivoted intermediate its ends upon apin 55. This rocker member 43 is of insulating material and at one end carries a contact or point 5| which is electrically connected to the aforesaid screw 41 by a spring contact strip 52. Cooperating with the contact 5| is a fixed contact or point 53 secured to an car 54 upon the base 44 and electrically connected or grounded thereto. The spring con- 5 tact strip 52 is so tensioned as to bias the end of the rocker member 49 carrying the contact 5| in an outward direction and normally maintain the contacts 5i and 53 in engagement. It is thus seen that the conductor 42 is normally effectively grounded through the contact strip 52, the contact points 5i and 53 and the base 44 which is secured to the carrier plate 2|. The winding 40 is thus normally shorted out. The end of the rocker member 4:! opposite to that carrying the contact 5| is provided with a toe which also, under influence of the tension of the contact strip 552, is urged inwardly into running engagement with the hub i! of the flywheel-blower member B. In the path of the toe 55 this hub H is provided with a groove 55 extending partially around the hub, and so long as the toe 135 rides in this groove the contact points 51 and 53 remain in engagement, as seen in Fig. 3. As the member 13 rotates with respect to the carrier plate 2|, or vice versa, the groove 56 will move out of engagement with the toe and a cam 51 on hub H oscillate the rocker member 49 so that the contact 5i is moved inwardly away from the contact 53, as seen in Fig. 6. When the points are in this position the shunt across the winding 40 is of course removed.

A laminated permanent field magnet 58 is secured, as indicated at 59 to the member B to turn therewith, and in a position to just clear the peripheral surface of the plate 2| and core piece 31. This field magnet 58 has poles 60 and El spaced apart in the direction of travel of the parts and which cooperate with the winding 40 in response to relative travel movement-oi these parts to induce a E. M. F. in the winding 40 in the usual manner.

In Fig. 6 I illustrate one manner in which the magneto may be connected to the external parts completing theignition system of the engine. As here shown, the winding 40 has its one terminal grounded, as indicated at B2, and the conductor 4! is shown as leading to this ground. The contact point 53 is also grounded. The other terminal of the winding 40 leads to the conductor 42, to the terminal screw 4'! and through the contact strip 52 to the contact 5i. Externally of the unit making up my present invention I provide a transformer 63 having a primary winding 64 one terminal of which is grounded, as indicated at 55 and the other terminal of which is connected by conductor 65 to the terminal screw 4'! of the interrupter 43. The transformer 63 has a secondary winding 51, one terminal of which is connected by conductor 53 to the insulated part of the spark plug 69. The other terminal of the secondary winding 57 is grounded, as indicated at T0, completing the circuit to the grounded shell of the spark plug. A condenser H is connected across the points or contacts 5| and 53 for the usual purpose.

It will be noted that my magneto is thus of the low tension type using an external tran former to develop the high tension alternating current potential required for producing the spark at the Spark p and that for leading on the induced E. M. F. developed in the magneto only a single flexible wire is required which may be con nected to the terminal screw 41 of the interrupter 43. Due to the limited oscillating movement of 75 the carrier plate 2| carrying this interrupter a flexible wire is sufficient, and no collector rings or brushes are required.

In the operation of cranking the engine, movable member B is rotated in the direction of the arrow G by hand, and far enough so that the dog 29 will first engage the catch 2! moving the carrier plate 2| from starting position of Fig. 3 to approximately the position of Fig. 5. During this movement, since the carrier plate 2! and the member B move in unison, the winding 40 and field magnet 58 have no relative movement but are carried along bodily or as a unit. Referring now to Fig 5, however, it will be apparent that as the angular face 3 engages the release pin 35 it will cam the dog .29 outwardly until the dog clears the catch 3|. Immediately as this happens, the spring 26 having been placed under considerable tension by the forward or energy storing stroke of the carrier plate 2!, will snap the plate 2i in the opposite direction, as indicated by the arrow F. This movement is extremely rapid and since the carrier plate 2! now moves backward or through a working stroke with respect to the member 13, it will be seen that the winding til will be carried in the direction of the arrow F across the poles of field magnet 58, as seen in Fig. 1, cutting the magnetic lines of force emanating from the magnet. The effect of this so-called impulse action is to cause a current to be induced in the winding 40 and it will be apparent (referring to Fig. 1) that the backward or working stroke of the parts will cause the toe 55 of the rocker member 59 to ride up on the cam 5i and open the contacts 5| and 53 so that the resulting surge potential will fiow through the primary winding 54 of the transformer 63. Ignition is thus provided for the en-- gine and if conditions permit it will fire and be set in operation. Obviously if the engine doesnot fire at the first such ope-ration it may be repeated as may be necessary.

As soon as the engine picks up speed the centrifugal force effective upon the dog 29 will cause it to swing outward so that it will clear the catch 3| and the carrier plate 2! will. then remain sta tionary, as will the coil 48. Each time, however, as the field magnet 58 passes the coil the corn tacts 5| and 53 will simultaneously open and a potential will be developed to maintain ignition. in the engine.

It will be noted that, in cranking, the magneto will develop a sparking potential at a different point during the travel of member B (and crankshaft Iii) than it will when the engine is running. Referring to Fig. l, at which point the engine has just fired upon being cranked, it will be evident that the coil 4%! has just traversed the field magnet poles, and returned to resting position. Referring to Fig. 3, however, it will be apparent, that when the engine is running, the field magnet poles will traverse the winding at a point earlier than the corresponding movement in cranking. Thus the spark is automatically retarded for most effective cranking or starting of the engine and is advanced when the engine is running.

My invention is particularly applicable to power plants of the type which comprise an in" ternal combustion engine and a generator driven thereby for providing electric power in places where commercial power is not available, and for small power units supplying mechanical power. Such power plants should, of course, be as compact and self-contained as possible for obvious reasons and my magneto as herein described,

being placed in a space otherwise not used and directly connected to the engine crankshaft, adds nothing to the overall size of the engine and facilitates the manufacture of an engine admirably meeting such requirements.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come Within the spirit and scope of the appended claims.

Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. An impulse magneto for an engine having a fixed frame part and a rotating part, comprising a carrier member mounted for oscillating movements upon said fixed part and spring biased to normally stand in one position, a magneto coil carried by said carrier member, a field magnet carried by the said rotating part for travel past the coil as the engine operates and to thereby induce a current in the coil, and means carried by the rotating part for engaging and oscillating the carrier member to a second position and return to said first position when the engine is cranked.

2. An impulse magneto for an engine having a fixed frame part and a rotating part, comprising a carrier member mounted for oscillating movements upon said fixed part and spring biased to normally stand in one position, a magneto coil carried by said carrier member, a field magnet carried by the said rotating part for travel past the coil as the engine operates and to thereby induce a current in the coil, and means carried by said rotating part for first moving said carrier member in one direction and then releasing the member for return movement under influence of its spring bias to thereby cause an impulse action of the magneto in cranking the engine.

3. An impulse magneto for an engine having a fixed frame part and a rotating part, comprising a carrier member mounted for oscillating movements upon said fixed part and spring biased to normally stand in one position, a magneto coil carried by said carrier member, a field magnet carried by the said rotating part for travel past the coil as the engine operates and to thereby induce a current in the coil, and means carried by said rotating part for engaging and operating said carrier member to provide an impulse action of the magneto, and said means being moved to an inoperative position by centrifugal force when the rotating part is rotated by the engine.

4. An impulse magneto mechanism of the character described and for an engine having a rotating element forming one of its working parts, comprising in combination, a carrier plate, a magneto coil on the plate, a magneto field magnet rotated by the said rotating element of the engine and cooperating with the coil as said element rotates to develop an electromotive force in the coil, the said carrier plate being movable to and between two positions and being spring biased to normally stand in a first position, and a member operated by said rotatable element and operative only at a cranking speed thereof to move the carrier plate to a second position and there release it for return by said spring bias to the first position to thereby obtain a rapid travel of the coil past the field magnet when the engine is cranked.

5. An impulse magneto mechanism of the character described and for an engine having a rotating element forming one of its working parts, comprising in combination, a carrier plate, a

magneto field magnet rotated by the said rotating element of the engine and cooperating with the coil as said element rotates to develop an electromotive force in the coil, the said carrier plate being movable to and between first and second positions and spring biased to normally stand in said first position, and a swingable member traveling With said rotating part and operative at cranking speeds thereof to engage the carrier plate and move it toward said second position and then release it to obtain an impulse action of the magneto when cranking the engine.

6. An impulse magneto mechanism of the character described and for an engine having a rotating element forming one of its working parts, comprising in combination, a carrier plate, a magneto coil on the plate, a magneto field magnet rotated by the said rotating element of the engine and cooperating with the coil as said element rotates to develop an electromotive force in the coil, the said carrier plate being movable to and between first and second positions and spring biased to normally stand in said first position, a swingable member traveling with said rotating REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,697,370 Ruppe June 1, 1929 1,975,644 Lesage Oct. 2, 1934 2,144,218 Dunham June 17, 1939 FOREIGN PATENTS Number Country Date 27,522 British 1903

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