US2249446A - Circuit breaker for spark distributors - Google Patents

Description

2 Sheets-Sheet l Filed Nov. 29, 1939 A. G. H. VANDERPQEL ETAL CIRCUIT BREAKER Fon SPARK DISTRIBUTORS.

July 15, 1941.

July 415, 1941. A. G. H. VANDERPOEL ETAL 2,249,445

` CIRCUIT BREAKER Foa sPARK DISTRIBUTORS C2707 axis fnl/enfans.'

Patented July 15', 1941 I CIRCUIT BREAKER FOR SPARK DISTRIBUTORS Albert G. H. Vanderpoel and William Ostling,

Los Angeles, Calif., assignors to California Machinery and Supply Co., Ltd., Los Angeles, Calif., a corporation of Delaware Application November 29, 1939, Serial No. 306,696

(Cl. 12S-117) 7 Claims.

:The present invention relates to improvements in circuit breakers for spark distribution in the ignition circuits of internal combustion engines.

The principal purpose of the present invention is to provide an improved means for controlling the spark gap opening of the circuit breaker in such a fashion that if the speed of the engine increases the spark is advanced, and the spark gap opening is decreased for a portion of the advancement and then held substantially constent.

The invention further contemplates a circuit breaker of the character described and means for controlling the advance of the spark in response to the speed of the gas fuel mixture passing through the carburetorof the engine. In this connection it is preferred to regulate the advance of the spark at full load by one means responsive to the suction in the intake conduit on the up stream side of the throttle valve through which the air and gas are admitted to the engine, and under road loads at high speed to advance the spark in response to suction on the down stream side of the partially open. throttle valve.

The invention is embodied in a device of the character described wherein Vacuum, created by the ow 0i gas and air in the fuel intake of the engine, acts against a spring loaded diaphragm to effect changes in the advance of the spark and in the opening provided in the primary circuit.

according to the invention, `the breaker.' arm is carried by a supporting member whichis movable about an axis that is offset with respect to the axis of the breaker cam. The offset is such that the heel ci the breaker arm backs away from the cam as the supporting member is initially moved by the suction applied to the dia- This backingA away of the heel as the breaker arm is advanced, permits the breaker arm to travel through a greater distance than the actual distance of spark advance. This is because part of the actual advance of the breaker arm is nulliled by the fact that the heel, when moved outwardly from the cam path first engages the cam at a point closer to the peak of the cam.

The additional breaker arm travel for a given spark advance'allows a greater movement of the diaphragm. The spring opposing the movementy of the. diaphragm can therefore be relatively weak and more accurate response to the initial low vacuums obtainable may be had. Of course the same general results could be accomplished by using a largerplate for the breaker arm to get greater distance from the pivot of the link on the breaker arm support to the cam axis. However, the size of the distributor would need to be increased and this is not economical. With our device, the size of the distributor may be just sufficient to give the clearance necessary between the high voltage terminals.

The features and advantages of the present invention will appear more fully as the description proceeds, reference being had to the accompanying drawings wherein a preferred embodiment of the invention is shown. It is to be un derstood, however, that the drawings and description are illustrative only, and are not to be taken as limiting the invention except insofar as it is limited by the claims.

In the drawings,

Fig. i is a View partly in side elevation and partly in section showing our improved distributor connected to the gas and air mixture intake pipe of an internal combustion engine;

Fig. 2 is a plan view of the distributor head with the cover removed;

Fig. 3 is a side view, partly in section, of the mechanism shown in Fig. 2; i

Fig. 4 is a diagrammatic view illustrating the manner in which the spark is advanced with re spect to the engine'driven cam, and

Fig. 5 is a sectional view illustrating a modication of the structure shown in'Fig, i.

Referring now in detail to the drawings, and in particular to Figs. l and 2, the present inven-I tion is shoviui` as applied to a distributor head iii. The general construction of the distributor head iii is conventional and will not be described in detail. 'The head Eli provides a bearing portion l i for a cam shaft i2. The shaft l2, in turn, car

ries a cam it that is adapted to engage a heel @d on a breaker arm i5.

The breaker arm l5 and the heel iii, which is usuallyl of a iibrous material, may be of any suit able construction. riihe breaker arm is pivoted by a pin it upon a supporting member il. The breaker arm carries a contact i8 which is adapt-n ed to engage a relatively xed contact i9 that is also supported on the member il'. The contact I9 is carried `by an adjustable stem 20 which, in turn, supported by a bracket 2| on the member il. AA spring 22 connects the breaker arm l5 to a bracket 23 on the member l1. .This spring is under tension so as to yieldingly urge' the breaker arm l5 toward the cam I3. The breaker arm and its spring are suitably insulated from the member H.

The supporting member l'l is journalled in a ball bearing 24 (see Fig. 3). The inner race 25 of this bearing is mounted on a depending ilange 26 of the member I1. The outer race 21 of the bearing is seated in a recess 28 that is formed directly in the body of the head I0. The recess 28 has its axis offset with respect to the axis of the cam I3. The principal part of the offset is in a direction toward the heel I4 0f the breaker arm I5 when it is in full load advance position,

-that is, in the direction of movement of the breaker arm by the cam, The axis of the recess 28 is also offset in a direction transverse to the movement of the breaker arm and toward the direction in which the member I1 is rotated to advance the spark. This latter oiset is only a fraction of the rst offset, however. For example, in the device as shown in the drawings, the central axis oi the bearing 24 is offset .10 inch toward the heel I4 from the axis of the cam I3 and .010 inch toward the pivot pin I6 of the breaker arm in a direction at right angles to the first named offset.

The supporting member I1 is adapted to be turned in the bearing 24 by a link 29 which is connected to the member I1 and to a diaphragm 30. The link 29 passes through a housing 3l to the diaphragm which is housed in a gas-tight housing 32. The diaphragm 30 receives atmospheric pressure on the link side thereof, but on the other side it is balanced between the pressure of a spring 33 and a reduced pressure or suction within the chamber 34 of the housing 32. It will be readily understood that by increasing the vacuum within the chamber 34, the atmospheric pressure on the diaphragm 30 can be made to compress the spring 33 and thus rotate the member Il in the direction of the arrow as indicated in Fig. 2, that is, in a direction to advance the spark.

The function of the offset member I1 is to so control the gap between the contacts I8 and I3 that as the spark is advanced there is initially a wide gap at idling position of the member II which decreases to a minimum value at full load position which is at about 22 of advance of the member l1. At or near the end of the 22 advance, the maximum gap opening is reduced to a minimum value, where it remains for a. substantial further period of angular advance of the member l1.

In Fig. 4, we have shown diagrammatically how this operation takes place. In the initial or retarded position of the member I1, the contacts i8 and i9 will be opened .035 inch by the cam striking the heel i4, Now, however, as the member i1 is turned to advance the spark, the gap narrows until the heel I4 is directly in line with the line connecting the axes of the cam I3 and the bearing 24. The minimum gap is .005 inch. It will be evident from Fig. 4 that as the heel I4 approaches the line drawn through the axes of the cam and bearing, there will be a substantial distance of its travel wherein there is a very slight variation in the gap as the member I1 is turned. This particular range of travel is represented by the in Fig. 4. I

We take advantage of the foregoing arrangement by utilizing the irst 22 of advance of the member I1 for controlling advance of the spark from no load position to full load position. Then when the vehicle is operating on the road at relatively high speed under road load conditions, that is, less than full load. the further advance indicated by the 10 in Fig. 4 may be utilized for the higher speed attained under road load without so narrowing the gap between the contacts I3 and Il as to make the circuit breaker ineective. Since a great deal of the operation of vehicles such as automobiles and trucks takes place under road load conditions, this feature is of particular advantage in prolonging the life of the distrlbutor'mechanism. For example, it will be appreciated that the heel rides with less force on the cam I3 as the spark is advanced, because the breaker arm is actually moved away from the cam, thus reducing the spring tension due to the spring 22. It is already known, in accordance with United States Patent No. 2,085,817, that there is less burning of the contacts in the distributor head because of the change in electrical dwell produced by the variable gap. That advantage is, of course, obtained here.

In order to control the rotation of the member I1 in response to the flow of gas and air mixture to the internal combustion engine, we provide one conduit 35 leading from the chamber 34 into the fuel intake conduit 31. An inverted Pitot tube 33 opens into the conduit 31 from the conduit 35. Thus the velocity of gas iiow through the conduit 31 will determine the vacuum in the chamber 34. An orice 39, which may be removed and replaced with one of a diierent size, connects the conduit 35 with the chamber 34. 'I'he size of this orliice 39 controls the amount of vacuum advance required.

When operating under road load conditions with the throttle valve partly closed, it is obvious that the velocity of gas flow through the conduit 31 will be considerably lower than that at full load operation. In order to obtain the proper spark advance under such conditions, we provide a second conduit 40 which opens into the chamber 34 through an orifice 4I controlled by a ball check valve 42. The conduit 40 opens into the fuel intake pipe 31 at 43. The point 43 is chosen so that when the throttle valve 44 is closed to idling position the inlet 43 will be on the upstream side of the valve. However, when the valve is partly open, as it will be for road load conditions, the opening 43 is on the downstream side and at the point of substantially the greatest velocity of air flow past the valve. In this position, the suction caused by the air Ilow past the opening 43 will create a higher vacuum in the chamber 24 than normal full load conditions, and thus advance the spark beyond the range of full load operation.

\ There is a retarding ellect on the spark advance under such conditions, however. This effect is established by the fact that when the vacuum in the chamber 34 is increased beyond a certain point, air is taken from the conduit 31 into the chamber 34 through the conduit 35, and this acts to odset the eiect'ot the withdrawal of air through the conduit 40. We 11nd that by properly proportioning the orifices 33 and 4I, the relation of full load advance to road load advance can be very nicely controlled.

In Fig. 5 we have shown a. slight modification of the construction illustrated in Fig. 1. In this figure, the conduit 4l is done away with, and a channel 4l is taken directly from the junction of conduit 35 which leads to the throat 36, through the wall of the fuel intake pipe 31, directly to the inlet 43'` A ball valve 42' is inserted in the channel 45 to serve the same purpose as the ball valve 42. The operation of this form of the invention is the same as the principal form.

Prom the foregoing description it is believed that the construction and advantages of the present invention will be readily apparent to those skilled in this art. Having thus described our invention, what We claim as new and desire to secure by Letters Patent is:

1. In a circuit breaker, for spark distributors for internal combustion engines, the' combination of a cam, a contact carrying breaker arm and a relatively xed contact, movable supporting means for said breaker arm. and said relatively fixed contact, said means being adjustable angularly about said cam, and mechanism connected to said supporting means for adjusting the same angularly about said cam, to advance or retard the spark, said supporting means being operable in its adjustment to decrease the separation ci the contacts by said cam during a portion of the angular movement of the supporting means to advance the spark, and said 'means being operable to maintain the separa- 'tion of said contacts substantially constant during a. further angular movement of the supporting means in a direction to advance the spark,V said adjusting mechanism comprising a pressure responsive diaphragm connected' with the intake of the carburetor of the engine at two different points therealong with one of the said connections open for flow in either direction and the other open for iiow only toward said intake.

2. In a. circuit breaker for spark distributors for internal combustion engines, the combination of a earn, a Contact carrying breaker arm.

and a relatively fixed contact, movable supporting means for said breaker arm and said relatively fixed contact, said means being adjustable angular-ly about said cam, and mechanismconnected to said supporting means for adjusting the same angularly about said cam, to advance or retard the spark, said supporting means being operabl in its adjustment to decrease the separation I the contacts by said cam during a portion of the angular movement of the supporting means to advance the spark, said adjusting mechanism comprising a pressure responsive diaphragm connected with the intake of the carburetor of the engine at two different points therealong with one oi the said connections open for flow in. either direction and the other open for 110W only toward said intake.

3. In a circuit breaker for spark distributors lfor internal combustion engines, said circuit breaker including a cam', a contact carrying breaker arm and a relatively iixed contact, movable supporting means for said breaker arm and said relatively fixed contact, said means being adjustable angularly about said cam, and mechanism connected to said supporting means .for

adjusting the same angularly about said cam, to advance or retard the spark, said mechanism comprising a pressure responsive diaphragm connected with the intake of the carburetor ofthe engine at two different points therealong with.

one of the saidconnections open for flow in leither direction and the other open for ow only toward the intake.

4. In a circuit breaker for spark distributors for internal combustion engines, said circuit breaker including a cam, a contact carrying breaker arm and a relatively fixed contact, movablesupportlng mea-ns for said breaker arm and said relatively xed contact, said means being adjustable angularly about said cam, andl mechanism connected to said supporting means for adjustingy the same angularly about said cam,

to advance or retard the spark, said mechanism comprising a. diaphragm, a conduit for applying suction to the diaphragm from the throat of the carburetor, and a second conduit for applying suctionto the diaphragm from the discharge side of the throttle valve in partly open position.

'5. In a circuit breaker for spark distributors for internal combustion engines, said circuit breaker including a. cam, a contact carrying breaker arm and a relatively iixed contact, movable supporting means for said breaker arm and said relatively iixed contact, said means being adjustable angularly about said cam, mechanism connected to said supporting means for adjusting the same angularly about said cam, to advance or retard the spark, said mechanism comprising a diaphragm, a conduit for applying suction to the diaphragm from the gas and air intake conduit of the engine, anda second conduit for applying suction to the diaphragm from the discharge side oi' the throttle valve in partly open position, said last named conduit being connected to the first named conduit through a check valve whereby suction from the discharge side of the throttle valve is relieved by reverse 'flow from the intake conduit through the first conduit, but reverse flow through the second conduit is prevented.

6. In a circuit breaker for spark distributors for internal combustion engines, said circuit breaker including a cam, a Contact carrying breaker arm and a 'relatively xed contact, movable supporting means for said breaker arm and said relatively xed contact, said means being adjustableangularly about said cam, and mechanism; connected to said supporting means for adjusting the same-angularly about said earn. to advance or retard the spark, said mechanism comprising a pressure responsive diaphragm connected with the intake of the carburetor of the engine at two different points at which the velocity flow of the gas and air diiers so as to cause substantially diierent suction cects on the diaphragm at the different points, the connection through which the greater suction eiect is exerted on the diaphragm with the parts in idling position being provided with a ycheck valve adapted to prevent flow therethrough from the intake.

7. In a circuit breaker for spark distributors for internal combustion engines, said circuit breaker including a. cam, a contact carrying breaker arm and a relatively xed contact, movable supporting means for said breaker arm and said relatively xed contact, said means being adjustable angularly about said cam, and mechanism connected to said supporting means for adjusting the same angularly about said cam, to advance or retard the spark, saidv mechanism comprising a pressure responsive diaphragm from which the connection is made to said adjustable supporting means, a conduit for applying suction on said diaphragm from the throat of the carburetor, a second conduit for applying suction on the diaphragm from the discharge side of the throttle valve in partly open position, and a check valve in said second conduit opening toward thecarburetor.

ALBERT G. H. VANDERPOEL. WILLIAM OSTLING.

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