US2311270A - Electrical circuit breaker system for ignition systems and the like - Google Patents

Description

Feb. 16, 194-3. G VANDERPQEL 2,311,270

ELECTRICAL CI RCU IT BREAKER SYSTEM FOR IGNITION SYSTEMS AND THE LIKE Filed April 25, 1941 2 Sheets-Sheet l 7 I, w 2% 24 244 2/4 2 3 T Mania? filial? Jamal.

u ifomq zzar A. G. H. VANDERPOEL 27 T BREAKER SYSTEM FOR IGNITION Feb. 16, 1,943.

ELECTRICAL CIRCUI SYSTEMS AND THE LIKE Filed April 25, 1941 2 Sheets-Sheet 2 Patented Feb. 16, 1943 UNITED STATES PATENT OFFICE ELECTRICAL CIRCUIT BREAKER SYSTEM FOR IGNITION SYSTEMS AND THE LIKE ware Application April 25, 1941, Serial No. 390,270

2 Claims.

This invention relates to electrical systems of the type in which an induced current is generated by abrupt change of current flow in a primary winding of an induction coil. The typical instance of such systems is the ignition system for an internal combustion engine. As applied to such a system, the general purposes of the invention include improvement in the timing of the high tension spark, especially at higher speeds, and improvement of the spark by providing a system using a heavy duty coil, and therefore passing relatively heavy current, without necessary increase in the size of the condenser, While at the same time increasing breaker point life.

In prior breaker systems, the separation of the breaker points causes the magnetic field of the previously magnetized coil to collapse, with the result that a momentary current flow is produced, in the same direction as the current flow that magnetized the coil, and this momentary current flow charges a condenser connected across the breaker points. This condenser then discharges, causing a current fiow in the reverse direction. This reversed condenser discharge current assists in demagnetizing the coil, and the rapidly collapsing field induces a high voltage in the secondary winding of the coil, sufiicient to produce a spark at the spark plug. The breaker point then close and current flows through the coil in the same direction as before, again magnetizing the coil, in readiness for the next separation of the breaker contacts. A certain definite time, however, is required for saturating the coil, and at high engine speeds, the coil may not be completely saturated before the breaker points again separate.

In accordance with the present invention, the current flow utilized to magnetize the coil fiows through the coil alternately in one direction and then the other for successive sparks, and it always fiows through the coil in the same direction as the immediately preceding condenser discharge current. The beneficial result is thus gained that the condenser discharge current assists not only in collapsing the field of the coil, but in building it up again, the coil being magnetized with a polarity the reverse of before, and the condenser discharge current being in the right direction to contribute to this reverse magnetization of the coil. The field of the coil is thus more quickly and strongly built up, and there is assurance that when the breaker points then separate, there will be a maximum voltage induced in the coil, with the result of maximum charging and discharging of the condenser, and hence a high tension spark of maximum intensity.

In one form of my invention, the breaker points are in serie circuit with the coil. Since the current flow is in reverse directions in the coil circuit for successive sparks, the are between the points reverses direction on each successive break, and thus compensates for the well known tendency for the metal of one point to be carried acros the gap to the other.

The invention will be better understood from the following detailed description of certain present illustrative embodiments thereof, reference for this purpose being had to the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of one form in which my invention has been successfully embodied in practice;

Fig. 2 is a timing diagram of the embodiment of Fig. 1, corresponding to one-half revolution of the operating cam;

Fig. 3 is a diagrammatic view of a modification of the invention; and

Fig. 4 is a timing diagram of the embodiment of Fig. .3, corresponding to one-half revolution of the operating cam.

In Fig. 1, the breaker mechanism is designated generally in diagrammatic form at l0, and a conventional distributor at H. Breaker mechanism In is shown to embody a usual four-lobed rotating cam l2 which operates on fibre or other insulation shoes l3 carried by a pair of pivoted breaker arms [4 and Ila. Arms I4 and [4a are -pivotally mounted at 15, and are spring urged to move towards cam l2 by means of fiat springs l6 anchored at H. Assuming an eight-cylinder internal combustion engine, cam l2 ha four lobes It! as illustrated, and the two breaker arms are, in effect, spaced apart by That is to say, when the mid-point of a cam lobe in in engagement with the shoe [3 of one breaker arm, the shoe 13 of the other breaker arm will be in engagement with a low point of the cam, midway between two lobes. In the particular embodiment here illustrated, the two breaker arms [4 and Ma are so located that their shoes l3 engage points .on the cam 12 which are 135 apart, which satisfie the conditions stated above.

The swinging ends of the two breaker arms M and 14a carry oppositely facing contact points, the arm l4 carrying points 20 and 2|, and the arm 14a carrying points 20a and 2 la. When the respective breaker arm shoes I3 are in register 55, with low points on the cam, as is arm H in Fig.

1, the contacts 2| and 2|a of the two arms engage with stationary contact points 24 and 24a, respectively, here shown as electrically grounded. During the respective times the shoes |3 ride over the cam lobes i8, the breaker arms are swung out and their contacts and 20a make with contacts and 25a, respectively.

Contact points 25 and 25a may be stationarily mounted, though I prefer to mount them on spring urged plungers 26, provided with suitable stops 2'! preventing them from advancing beyond positions in which a proper gap is established between the contact points 25 and 25a and the contact points 20 and 20a, respectively, when the breaker arms are moved in the directions of the points 24 and 24a. An advantage of the plunger mounted contact points 25 and 25a is that a shorter gap between points for a given.

movement of the breaker arm is obtainable.

The usual storage battery is indicated at B, its negative terminal grounded, and its positive terminal connected by branching leads 3!! and 3| to the contact points 25 and 25a.

A usual coil, though preferably one of heavy duty character, is indicated at C, its primary winding connected at one end by lead 36 to breaker arm l4, and therefore to contact points 20 and 2|, and at the other end by lead 31 to breaker arm Ma, and therefore to contact points 23a and 2|a. The high tension secondary winding 38 of coil C is here shown as connected at one end to ground and at the other end to the conventional distributor In the instant form of my invention the pairs of contacts 2|, 24 and 2|a, 24a serve as alternately used breaker points, and a condenser is connected across each such pair of points. The indicated condensers and 40a, shown as connected between leads 36 and 31, respectively, and ground, will be seen to be across the two pairs of contact points mentioned. It was stated above that the coil C is preferably a heavy duty one. By this is meant a coil having a resistance sufficiently low that, usinga battery-B of 6 volts, there will be a current flow of say from 12 to 14 amperes in the primary circuit of the coil when the battery circuit is closed. Despite the use of this heavy duty coil, I find it preferable, in my system, that the condensers 40 and 40a be of ordinary size, or of about .025 mf.

The sequential operation of the contact points as the operating cam 2 rotates is as follows, reference being had to the timing diagram of Fig. 2, in which the arrow lengths represent the periods of closure of the cooperating pairs of points, and the arrowheads represent the times of separation of the points.

against contact point 25a, rotation of-the' cam right handedly first causes outward movement of breaker arm [4 to separate contact point 2| from'contact point 24. A few degrees of cam rotation later, breaker arm I ia has moved inwardly sufiiciently far to separate point 20a from point 25a, and by this time breaker arm M hasing separation of points Zia-and 24a, the arm Starting with the position of Fig. 1, in which contact point 2| is against contact point 24, and contact 26a is l4 separates point 20 from point 25. At this time, arm Ma moving outwardly closes point 20a with point 25a, and. shortly after, arm I4, still moving inwardly, closes point 2| with point 24. The breaker arms are then back in the assumed starting position. Thus, as here embodied, the pairs of points 2| 24 and 2|a, 24a both close and separate While the respective pairs of points 20a, 25a and 20, 25 are closed.

When the points are in the position of Fig. 1 (points 2|, 24 closed and points 20a, 25a closed), current flows from the positive terminal of battery B via lead 3|, points 25a and 20a, breaker arm Ma, and lead 31 to the primary winding of coil C, thence via lead 36 to breaker arm I4, and through contacts 2| and 24 to ground. This current flow magnetizes the coil, and the breaker f. mechanism is in position for immediate separation of points 2|, 24 to break the circuit and cause a high tension spark, as later to be more fully described. When the points are in the opposite position, that is, with points 2|a and 24a closed and points 23, 25 closed, current then flows fom battery B via lead 30, contacts 25, 20, breaker arm l4 and lead 36 to the primary winding of the coil, and from there via lead 31, breaker arm Ma, and contacts 2|a and 24a to ground. It will be seen that the current flow through the coil is then reversed, and the coil will accordingly be magnetized with reverse polarity. The breaker mechanism is at this time in readiness for separation of contacts 2|a and 24a, which will break the circuit and cause the high tension spark.

The described contact points thus function as a pole changing switch, causing the polarity of the coil to be reversed with each magnetization by reversing the direction of current flow through the coil. As will be evident, the points are operated to break the circuit at points 2|, 24 when the coil is magnetized with one polarity, and to break it at points 2|a, 2411 when the coil is magnetized with the opposite polarity.

Assume again that the contact points are in the position of Figure 1, and that battery-current is therefore flowing through the coil in a direction from lead 31 through the'primary of the coil toward lead 36. The primary of the coil is thus energized. As contact point 2| then separates from contact point 24, the circuit is suddenly broken, and the field of coil C collapses. The collapsing field induces a current flow in the same direction as the current flow which originally magnetized the coil, and this current flow charges the condenser 40, the side of said condenser connected to ground being negatively charged and the side of the condenser connected to lead 35 assuming a positive charge, as Willbe evident. The condenser Ml then immediately discharges, and the condenser discharge current is in a direction through the primary of coil C the reverse of the current which originally magnetized the coil. This condenser discharge current therefore assists in demagnetizing the coil, causing a complete collapsing of the field in a shorter time than would otherwise be possible as is well understood. It will further be understood how this collapsing of the field of coil C induces a high tension current in the secondary winding 38 of the coil, producing a high tension spark at the spark plug to which the coil i then connected by the distributer i.

The condenser discharge current through the coil not only reduces'the magnetization of the "coil to zero, but begins to build up the magnetization of the coil in the reverse direction before the circuit is opened by separation of contacts a and a. and 25a is accompanied by closure of point 20 with point '25, which is followed immediately by closure of point *2 la with point 24a, a previously described. Battery current now again flows through the coil, but in the reverse direction, as before stated. Thus the coil C is now again magnetized, but with its polarity reversed. And it will be seen that the current flow which has just magnetized the coil C has been in the same direction through the primary of the coil as the discharge current from the condenser 48, the condenser discharge current first having acted to completely demagnetize the coil and then to magnetize it partially with reversed polarity, and the battery current then following along to build up the magnetization of the coil in the direction in which it was started by the condenser discharge current.

Similar events occur as cam |2 causes, first, separation of contact point 2|a from contact point 24a, then separation of point 20 from point 25, together with closing of point 20a and. 25a, and finally closing of points 2| and 24. Thus, the breaking of points 2|a and 24a first causes a collapsing of the field of the coil, which induces a voltage charging the condenser 40a, the direction of current flow being the same as the current which magnetized the coil. The condenser 40a then discharges, producing a current in the reverse direction which assist in the demagnetization of coil C, and in initiating the building up of the magnetization of said coil in the reverse direction, to be completed, upon closing of points 20a and 25a and of points 2| and 24, by battery current flowing in the same di motion as the described discharge current of condenser 40a.

Thus it is a. novel characteristic of my system that the current flow through the coil is in reverse directions for successive magnetizations; so that its polarity is reversed each time it is magnetized. And further, the condenser discharge current, which is responsible for the high tension spark in the secondary circuit, is always in the direction in which the next magnetizing current is to flow, so as to assist in the next magnetization of the coil. This provision assures proper and maximum magnetization of the coil, even at highest engine speed, and therefore assures development of maximum voltage when the breaker contacts are separated.

In the form of Fig. 1, the described cam operated contact points serve as a pole changing switch and also as the circuit breaker. Fig. 3 shows a modification, in which the mechanism and circuiting as shown in Fig. 1 are again employed, but in which the function of breaking the battery-coil circuit is delegated to a third breaker arm 40, operated by a second cam 4| rotating synchronously with cam |2, breaker arms I4 and Ma retaining the function of pole changing switch. It will be understood that the sequence of makes and breaks of the contact points controlled by the breaker arms 14 and Ma will be the same as described in connection with Fig. 1. Arm 40 carries a contact point 42, adapted to make with stationary contact point 43, and the points 42 and 43 are in series with the primary winding of the coil C, as indicated. The points 42 and 43 being the main breaker points, a condenser 45 is connected across them, as indicated, and if necessary to avoid arcing, con- Separation of contacts 20a densers 4B and 41 may be connected across the pairs of contacts 2|, 24 and 2|a, 24a, being here shown as between breaker arms l4 and Ma, respectively, and ground.

Cam 4| has twice the number of lobes as cam I2; for an eight cylinder engine, cam |2 will have four lobes and. cam 4| eight lobes.

Operation is as represented in the timing diagram of Fig. 4. Fig. 3 shows the mechanism in a position with points 42 and 43 separated, and points 2| and 24 just about to separate, Fig. 4 showing that the contacts 2| and 24 separate several degrees of rotation of the cams after separation of points 42 and 43. The separation of points 42 and 43 opens the circuit magnetizing the primary winding of coil C, allowing the magnetic field to collapse. This induces a current in the coil circuit in the same direction as the battery current which magnetized the coil, which current charges the condenser 45. The condenser 45 then discharges, and the condenser discharge current is in the reverse direction in the circuit, and hence assists in collapsing the field of the coil C. The rapidly collapsing field induces a high tension current in coil secondary winding 38, causing a high tension spark at the spark plug.

Shortly after the break of the points 42 and 43, there follows, in succession, as a result of the action of cam l2, separation of points 2| and 24, separation of points 20a and 25a and closing of points 20 and 25, and closing of points 2|a and 24a. Points 42 and 43 also close, preferably after closing of points 2|a and 24a. This succession of operations sends battery current again through the coil C, but in reversed direction, the same as in the system of Fig. 1. The primary winding of coil C is accordingly again magnetized, but with reversed polarity. And again, as with the system of Fig. 1, the condenser discharge current that fiows following the above described breaking of points 42 and 43 is in a direction the reverse of the current which magnetized the coil on the immediately preceding magnetization, but is in the same direction as the battery current next to fiow through the coil, and therefore is in a direction not only to demagnetize the coil, but to contribute to the next succeeding magnetization of the coil.

The difference between the system of Fig. 1 and that of Fig. 3 resides in the fact that the main breaker points 42 and 43 are directly in the circuit of the coil, and that the current flow through said points reverses direction for each break. This constant reversal prevents the metal from being carried from one point to the other, and substantially increases the lives of the points.

In Fig. 3, as well as in Fig. 1, the two breaker arms I4 and Ma engage points on the cam I8 which are in effect, spaced apart by 45, being spaced apart in the illustrated embodiments by plus 45, or By this arrangement one breaker arm moves outwardly while the other moves inwardly, and vice versa. It will be unis obtained, the arrangement being a i ull equiv-- alerit of that illustrated in Figs. land'3.

1. In ignition systems or the'like; a coil having primary and secondary windings and'amagnetiza'ble core, a source of' current for energiz 2; In-ignitionsystemsor thelike; a coil'h aving prim'ary and-secondary windings and a magne't'izable core-a source of direct current for energi'zing-the primary'win'ding of said coil, electric circuiting including a single combination power operated pole changing switch and circuit breaker for conducting current from said source to the primary winding of the coil; said polechanging'switch and circuitbreaker being adapted to periodically reverse the direction of current flow tothe' coil, and to break the cir-' cuiting' at two points successively in each r eversal of the current flow to thecoil, and condensers connected across the'points at which the Y circuit is first broken'as the switch operates to reverse the c'urrent'flow;

ALBERT G. H. VANDERPOEL.

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