US2791649A

US2791649A - Distributor construction

Info

Publication number: US2791649A
Application number: US446731A
Authority: US
Inventors: Stephen C Baker
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-07-30
Filing date: 1954-07-30
Publication date: 1957-05-07
Anticipated expiration: 1974-05-07

Description

y 7, 1957 sis BAKER 2,791,649

DISTRIBUTOR CONSTRUCTION Filed July so, 1954 2 Sheets-Sheet 1 INVENTOR.

38 Q4 0904 flag/aux M y 7, 1957 s. c. BAKER 2,791,649

DISTRIBUTOR CONSTRUCTION Filed July 50, 1954 2 Sheets-Sheet 2 United States Patent DISTRIBUTOR CONSTRUCTION Stephen C. Baker, North Riverside, Ill. Application July 30, 1954, Serial No. 446,731

12 Claims. (Cl. 200-30) This invention is concerned with ignition systems for gasoline engines and the like, and more particularly with an improved distributor construction.

It is Well recognized that a hot spark, i. e. one of h gh energy content, at the spark plugs of a gasoline eng ne is highly desirable. A hot spark improves acceleration and gasoline mileage, and also materially improves starting in cold weather. Generally, it also leads to less fouling of the spark plugs and of the combustion chamber. It further insures complete combustion and thereby precludes backfiring in the exhaust system and prevents condensation of gasoline on the cylinder walls which tends to wash lubricant from the cylinder walls to increase wear on the pistons, piston rings, and cylinder walls.

In substantially all automobile and similar gasoline engines today, the spark at a spark plug is produced by a distributor and a high voltage coil. Breaker points serve to connect the automobile battery to the primary of a step-up transformer, and the breaker points are opened periodically by a cam driven from the engine to cause the magnetic field established by the current flowing through the primary to collapse, thereby generating a high potential in the secondary. This high potential is distributed in proper sequence to the various spark plugs of the engine by means of a rotor and distributing contacts in the distributor. The more cylinders there are in an engine, the more often the breaker points have to open for a given engine speed. Thus, the time between opening or breaking of the points is reduced with increase in the number of cylinders, and as a result there is little time for saturation of the core of the transformer or ignition coil. Consequently, the higher engine speeds and the six and eight cylinder engines, particularly the latter, used almost exclusively in automobiles produced in the United States allow little time for core saturation, and this time decreases with increasing road speeds and the corresponding greater engine speeds. Thus, modern engines have a tendency to produce a weak spark, and this tendency increases with speed, thus robbing the engine of high speed performance. The cams for operating the distributor breaker points are of hexagonal and octagonal construction, respectively having six and eight lobes in accordance with the number of cylinders of the engine. When the cam follower rides on one of the flats of such a cam, the ignition coil core is allowed to saturate to a greater or lesser extent. Accordingly, the core saturation period i generally referred to as dwell time. Holding tolerances to extreme precision, the maximum dwell period which can be attained with conventional construction for an eight cylinder engine is about 80 percent.

The more rapidly the current is cut oil in the primary of the coil, the more rapidly the magnetic field collapses, and hence the greater is the voltage induced in the secondary, and the hotter is the spark. The adjacent faces of an eight lobe cam as used with eight cylinder engines are positioned at 135 relative to one another, while 2,791,649 Patented May 7, 1957 2 those of a six lobe cam are at only a slightly sharper angle. Thus, the lobes are rather broad and the points cannot be openedas quickly as is desirable. As a result, the spark is not nearly as hot as it should be.

Furthermore, the cams are universally mounted radially inwardly of the breaker points relative to the distributor shaft, and the linear speed of the cam surface is quite limited, thus further limiting the speed with which the breaker points can be opened. This places a further limit on the hotness of the spark.

It is an object of this invention to provide a distributor producing a hotter spark than heretofore thought possible for multicylinder high speed engines.

A further object of this invention is to provide a distributor for rnulticylinder engines providing a greater percentage of dwell time for a given number of cylinders than heretofore thought possible.

A further object of this invention is to provide a distributor for breaking or opening the breaker points with extreme rapidity to produce a hot spark.

It is a further object of this invention to provide a distributor utilizing a plurality of arcuately spaced rollers rather than the usual cam for opening the breaker points.

It is a further object of this invention to provide a distributor wherein the contact breaking means rotates around the outside of the breaker points thereby providing a higher linear speed to the breaking means for any given speed of rotation.

More specifically, it is an object to provide a distributor having a cage comprising a large number of rollers corresponding in number to the cylinders of an engine and rotating radially outwardly of the breaker points.

Yet another object of this invention is to provide a distributor construction as contemplated by the foregoing objects in combination with a breaker point construction having remarkably low inertia to facilitate rapid opening and closing of the points by the structure heretofore outlined.

In accordance with the foregoing objects, the distributor hereinafter to be described utilizes a set of breaker points mounted on a breaker plate fully compensated for spark advance in accordance with engine requirements by means of both centrifugal and vacuum advance. The moving parts of the breaker points are small in size and weight so as to have minimum inertia, and the cage carrying a plurality of rollers determined in accordance with the number of cylinders of the engine, viz. eight rollers for an eight cylinder engine, periodically to open the breaker points in proper timed relation with the rotation of the engine. One trouble heretofore not mentioned which has plagued high speed operation of modern engines is breaker point float. The inertia of most breaker points causes the cam followers associated therewith to leave their respective cams at high speeds. As a result, the points do not reclose as soon as they should, the dwell time is decreased, and the spark is weakened. The small size and low inertia of my breaker points minimize floating. Floating also can be minimized by decreasing the breaker point gap, i. e. the maximum distance which the points separate when open. However, with conventional breaker points decreasing the gap below a certain minimum causes the points to burn up with rapidity. Metal is carried by the are associated with breaking from one of the contact points to the other, thus causing pitting of the first contact point and building up of material on the second contact point. The metal is oxidized as it is carried by the arc, and since the oxide of the metal has a larger volume than the metal itself, the build-up on the second contact point is more rapid than the formation of the pit in the first contact point.

in my copending application Serial No. 400,175, filed have disclosed a breaker point construction wherein the points are eccentric relative to one another and one of the points is rotated eccentrically from time to time to bring fresh contacting surfaces into engagement. This permits a much closer setting of the breaker gap than is possible with prior constructions.

' According, it is yet another object of this invention to provide a distributor construction as heretofore outlined in combination with breaker points one of which is ec centrically'rotatable about the axis of the other to' enable anextremely close gap to be set, thereby reducing float to an absolute minim-um; 7

With the construction heretofore outlined I havebeen able to obtain a dwell time of approximately 92 percent as against the previous maximum of percent, and to obtain a breaking action more than three times the stand ard speed. "A constant, hot spark is maintained through the fullrange of e ngine speeds, and the life 9f the breaker points is" materially extended. A manufacturing, advantage is obtained by placingthe contact breaking means radially outwardly of the paints. A rnaxirnumradius forlthe breakingmeans thus is obtained fQI'QQY iYQn size of distributor, and maniifactur'ing tolerances can be made much greater inasmuch as anyvariation on an absolute scale will be much less percentagewise. with the larger'a'dius'.

"Other andfurther objects and advantages of the. present inv ention will be apparent from the following description when taken in connection with the accompanying drawings wherein: V l

"Fig'fl is a top view of a distributor constructed in accordance with the principles of my invention, the distributor cap and a sealing plate thereunder being removed fer purp'osesl of illustration;

"'Fig." Z'isa horizontal sectional view on an enlarged scale'of a portion of the breaker point opening means as taken along the line 2 2 of Fig. 4;

' Fig. 3 is a perspectixje view of the structure shown in section in Fig. 2; i

Fig. 4is a vertical sectional viewthrough the distributort'aken substantially along the line 4--4 in Fig.1;

i Fig. 5 is a view generally similar to Fig. .1 withthe pa r'tsin' adiiferent position of operation;

Fig. 6 is a vertical sectional view taken generally along the line (s- 6 or Fig. 5;

"'Fig'f 7 is a fragmentary perspective view of the breaker point mechanism; 4

FigTBis a vertical sectionalview throughthe breaker point'rnec hanism as takensubstantially along the line & 5

Fig.9 isa fragmentary, exploded perspective view of the'piyot of the breaker pfoint mechanism; and

Eig. it) is a cross-sectional view showing the mounting of smile of the breaker point mechanism as taken sub stantially along the line 10-10 in Fig. 6.

. Referring now in greater particularity to the drawings, therewill be seen a distributor 20 constructed in accord ance .with th principles of my invention and comprising a body or housing '22 of steel or other suitable material and preferably provided with circumferential fins 24 for heattransfer to maintain the interior of the'distributor cool, and further to improve the appearance of tributor. The distributor body is generally cup shaped in accordance with conventional practicefhaving a c ylindrical hollow interior 26. 'A sleeve 28 which prefer; ably is integral with the bottom 3t) of the distributor body extends axially downward from the distributor body l and is provided with sleeve bearings 32 whichimay be of the permanently lubricated, porous bronze variety. The sleeve bearings rotatably journal adistributor sliaft 34.

The bottom 30, provided with 'arcuately spaced breathing ports 36, and the outer ends ofthese ports pref; erably are closed off .by a suitable materialisuch as felt 38 topreclude the entrance ofdir't and the like while allowing breathing.

The top of the distributor body is provided along its inner edge with a recess or shoulder 40 on which an insulating plate 42 seats. The plate 42 may be provided with suitable projections or other means (not shown) extending upwardly from its surface for simplifying retraction thereof. The usual insulating distributor cap 44 seats on top of the body 22 and is held thereon in accordance with conventional practice by a pair of spring clips (not shown). The distributor cap is provided with a plurality of contacts 46, there'being eight such contacts in the exemplary embodiment, and with a central contact 48 of graphite or carbon and pressed lightly by a compression spring (not shown).

A rotor 50 of molded plastic or other suitable insulating material is mounted on the upper end of the distributor shaft 34 above the plate 32 and beneath the cap 44 being fixed against rotation on the shaft by any known or suitable means such as cooperating flats on the shaft and in the rotor. A radially disposed contact bar 52 is riveted or otherwise suitably secured to the top of the rotor and is in constant engagement with the centralcontact 48 moving from cooperative engagement from one to another of the arcuately spaced contacts 46 in accordance with rotation of the engine.

A contact actuating member or cage 54 is provided with an integral downwardly extending boss 56 and with an integral upwardly extending sleeve 58, the boss and sleeve being provided with a continuous cylindrical opening receiving the distributor shaft 34. The cage is arcuately rockable on the distributor shaft, but does not rotate continuously thereon and no anti-friction means or sleeve bearing is necessary for mounting the cage on the shaft. The boss 56 extends down into a centrifugal advance mechanism 58 of conventional construction and rests on a shoulder (not shown) of the distributor shaft 34', the lower end of the shaft being of larger diameter than the upper end.

, Theupper face of the bottom section or wall 30 of the distributor body has an annular recess 60 providing a shallow central boss 62. An anti-friction washer 64 of any suitable material such as nylon rests on top of the boss 62 and on top of the sleeve bearing 32, the centrifugal advance mechanism 58 resting on top of this washer. The centrifugal advance mechanism 58 may be of any suitable or well-known design including weights pivotally mounted on a frame attached to the distributor shaft and spring urged inwardly. With increasing engine speed and with correspondingly increasing distributor shaft speed, these weights' flyoutwardly against the action of their springs, and pins 66 extending upwardly therefrom into anintegral radial plate 68 of the cage serve to advance the plate arcuately with respect to the distributor shaft 34 for spark advance at'hig'her speeds.

The cage' 54 is provided with an upstanding peripheral flange 70. This'flange, as best may be seen in Figs. 1-4, is provided with eight openings or recesses 72 preferably cut into the flange'from the outside thereof, leaving a continuous upper band'74 and a rim 76 upstanding from the plate 68. The cage could be made in several parts, but it preferably is machined from a single piece, thereby insuring concentricity with accompanying proper balance and spacing relative to the breaker point mechanism shortly to be described. The cage preferably is formed ofaluminum to simplify machining, and to hold down mass and inertia whereby slight manufacturing tolerances will not produce excessive eccentric masses to cau e vibration, and whereby the centrifugal advance mechanism more readily will advance or retard the cage without time lag. The recesses or openings 72'are determined in accordance with the number of cylinders of the engine, there being eight such recesses in theexemplary embodiment. Metal pins 78 extend vertically through each recess from the rim 76 to the band 74, and rollers 80 are 'rotatably mounted thereon. The rollers preferably emu...

are made of nylon due to its light weight, physical strength and resistance to abrasion and self-lubricating properties. The rollers extend inwardly beyond the peripheral flange or wall 70 for engaging a breaker point mechanism as hereinafter will be described. It will be observe-d in the illustrative example of this invention that there are eight such rollers 80.

An anti-friction bearing such as a roller bearing 82 is journaled on the upstanding sleeve 58 of the cage and is held thereon by a snap ring 84 fitting in a suitable annular recess in the sleeve. The bearing 82 has journaled thereon an upstanding hub 86 welded or otherwise suitably secured to or formed integral with a breaker plate 88.

An arcuate mounting member or plate 90 (see particularly Figs. -7) is held on the plate 88 by means of screws 92 passing through elongated slots 94 in the mounting member 90 and threaded into the plate 88, thereby providing for adjustment of the mounting member. A bracket 96 is carried on the mounting member 90 and is secured thereto by any desirable means such as screws or rivets 98 and suitable insulating plates 100. The bracket 96 is provided with an upstanding flange 102 on which there is mounted by means of a rivet 104 or the like a leaf spring 106. The flange 102 has an angularly disposed extending end or pivot plate 108 having a transverse groove 110 therein. The groove communicates with a slot 111 (Fig. 9) through the pivot plate.

A rocker arm 112 of sheet metal construction is arranged with its plane perpendicular to that of the pivot plate 108, and a wire hook 114 extends from the forward portion of the arm as at 116 to the end of the leaf spring 106 as at 118.

The rocker arm is provided intermediate its ends with a right angularly disposed pivot comprising a sheet 118 perpendicular to the arm and having a transverse knife edge 120 fitting in the groove 110 for pivotally mounting the arm. An extending tip 121 (Figs. 1, 5, and 9) extends through the slot communicating with the pivot groove 110 to form an electrical terminal. A central portion of the sheet 118 continues back over the rear end of the arm as at 122, thereby providing a cam follower which is rigid and which is sufficiently wide to avoid cutting into the nylon rollers 80. It will be observed that the cam follower section presents a rather sharp shoulder engageable with the rollers 80 as best may be seen in Figs. 1 and '5 for rocking the arm 112 with extreme rapidity when the cam follower 122 engages one of the rollers 80. The rocker arm is completed by an ignition or breaker point 124.

The plate 88 is provided with an upturned flange or tab 126 aligned with the breaker point or contact 124, part of the plate 88 being cut away in the vicinity of the pivot plate 108 and the rocker arm 112 to provide clearance therefor. A breaker point 128 is eccentrically mounted on a rotary in the flange or tab 126, and a ratchet wheel 132 having crown teeth 134 thereon is aflixed to the rotary mounting member 130 concentrically therewith.

The breaker points 124 and 128 hereinafter will be referred to as relatively movable and relatively fixed breaker points by analogy with the corresponding points of conventional construction.

A post 134 is provided with a reduced top portion or pin 136 on which there is pivotally mounted an arm 138, a washer 140 or the like being welded or otherwise secured on the pin 136 to hold the arm 138 flatly, but pivotally, on top of the post 134.

A second post 142 is spaced from the first and has a reduced diameter upper end portion 144 projecting upwardly therefrom, the reduced diameter portion having a circumferential groove 146 therein. A hairpin spring 148 has it bight curled around a pin 150 fixed on the arm 138 with one of the legs 152 of the spring engaging in the groove 146 of the reduced diameter portion 144 on the inside thereof, and with the other leg 154 having a member 130 (Figs. 7 and 8) journaled curled over tip 156 embracing the outer edge of the arm 154 to bias the arm inwardly. The reduced upper end 144 fits through a transversely elongated slot 158 in the arm to allow pivoting of the arm about the pin 136, and the spring normally biases the arm inwardly to hold a lateral projection or stop 160 thereon against the hub 86.

A pawl 162 is pivotally mounted on the outer end of the arm 138 by means of a pin 164, and a spring 166 (Fig. 8) coiled around this pin bears against the arm and against the depending flange 168 on the pawl to urge this flange against the teeth of the ratchet 132.

The distributor 20 is provided with the familiar vacuum fitting 170 secured by means such as a screw 172 to the outside of the distributor body and connected by means such as a vacuum line 174 to the carburetor or intake manifold in accordance with conventional practice. The fitting, as is well known, incorporates a flexible dia' phragm spring urged toward the distributor and vacuum urged away from the distributor. An arm 176 extends from the diaphragm through a suitable slot 178 (Fig. 4) into the distributor housing. A hole in the arm pivotally receives the pin 136 as may be seen in Figs. 1 and 5, while the extending end of the arm is provided with a transversely elongated slot 180 pivotally and slidably receiving the pin 150. Thus, the spring normally forces the distributor plate 88 to the position shown in Fig. 1. Simultaneously, the arm or link 176 forces the arm 138 in a counterclockwise direction away from the hub 86, thus retracting the pawl flange 168 across the teeth 134 of the ratchet wheel 132. Each time vacuum is increased in the carburetor or intake manifold by increased engine demands, the link 176 is retracted to the position shown in Fig. 5, thus rocking the breaker plate 88 to advance the spark, and simultaneously allowing the hairpin spring 148 which was cooked in the position of Fig. 1 to pivot the arm 138 to cause the pawl flange 168 to rotate the ratchet wheel 132, thereby presenting a fresh surface of the relatively fixed contact 128 for engagement by the relatively movable contact or breaker point 124. Actuation of the ratchet wheel under the influence of the spring 148 is preferable to actuation by a direct physical force as the relatively fixed contact point when spring moved will generally rotate eccentrically only when the breaker points are broken or out of engagement, thus avoiding sliding or scraping of the surfaces together with attendant wear.

The relatively fixed contact or breaker point 128 is grounded as will be understood. The relatively movable point is insulated from ground by the insulating means mounting the bracket 96. A flexible lead 182 (Figs. 1 and 5) extends from the projecting terminal 121 of the rocker arm pivot to an insulated connector 184 connected to a screw 186 passing out through an insulated sleeve in the side of the distributor body and connected by means of a wire 188 to the high side of a condenser 190 mounted on and thereby grounded to the distributor body. A nut 192 on the screw 186 holds the wire 188 on the screw, and it will be appreciated that this nut also will hold the lead running from the low tension coil of the ignition transformer.

It now will be seen that the distributor herein shown and described meets the objects of the invention. The nylon rollers coupled with the sharply rounded cam follower of the breaker points effects extremely rapid opening and closing of the breaker points with a higher percentage of dwell time than heretofore thought possible with engines with a substantial number of cylinders, such as six, eight, or more. The placement of the rollers radially outwardly of the breaker points provides a higher linear speed for the rollers than has been possible with the centrally disposed cams heretofore used, thus contributing to the rapid making and breaking of the points, and this disposition further serves to minimize manufac turing errors percentagewise. The light weight of the breaker or rocker arm combined with the central pivot thereof renders the arm capable of extremely rapid movement and'tends to eliminate floating at high speeds. Bloating further is minimized or. eliminated by the short movementof therockerarm, and movement of the rocker arm is .kept ata minimum by use of the eccentrically rotatable'breaker' pointswhich allow a closer gap setting smaller than that heretofore thought possible.

Various changes in structure from the exemplary embodirnenti'hereinshownand described will no doubt occur to those skilled .in theart and are to be considered as form-ing apart of my invention insofar as they fall within the spirit and scope of the appended claims.

I claim:

- 1. Adistributor constructioncomprising a distributor housing, a distributor shaft rotatable in said housing, a breaker. plate mounted in said housing about'said shaft and limited in arcuate movement about said shaft, a breaker. .point structure mounted on said breaker plate and including a follower for effecting breaking of the points of said structure, a substantial number of rollers, and means on said distributor shaft carrying said substantialnumber of rollers in arcuately spaced relation outwardly of'the breaker point structure for planetary movement with said shaft and engageable with said follower for quickly making and breaking the points of said breaker. point structure.

2. A distributor construction comprising a distributor housing, a distributor shaft rotatable in said housing, a breaker plate mounted in said housing about said shaft and limited in arcuate movement about said shaft, a breakerpointstructure mounted on said breaker plate and including. a follower for effecting breaking of the points of said. structure, a substantial number of follower engaging members, and means on said distributor shaft mounting said members r ally outwardly of the breaker point structure. and in arc .tely spaced relation and rotary with said shaft successively to engage said follower to effect rap-id making and breaking of the points of said structure.

'3. A distributor construction as set forth in claim 2 wherein the follower engaging members comprise a substantial number of rollers.

4. A distributor construction as set forth in claim 3 wherein the rollers are made of nylon.

5. A distributor construction comprising a distributor body, a distributor shaftrotatable in said bady, a breaker plate in said body around said shaft and limited in arcuate movement about said shaft, a breaker point structure on said plate andincluding a pair of breaker points and a rocker arm, one of said points being mounted on said rocker arm, and said rocker'arm having a foliower, a cagecarriedby saiddistributor shaft and rotatable therewith, said cage including a cylindrical wall having a pinrality of arcuately'spaced openings therein, and a pinrality ofrollers carried by said cage in said openings substantially parallel to said distributor shaft and concentric thereabout, said rollers projecting at least in part into position successively to engage said follower for making and breaking said points.

.6; A distributor construction comprising a distributor body, a distributor shaft rotatable in said body, a breaker plate carried in said body about said shaft and limited in arcuate movement about said shaft, a rocker arm pivotally mounted from said plate and having a follower and a relatively movable breaker point thereon, a relatively-fixed breaker point carried from said plate in opposition to said relative movable breaker point and eccentrically movable about the axis of said relatively movable breaker point, means including resilient means for eccentrically rotating the relatively fixed breaker point from time to time, means for cocking said resilient means to rotate said relatively fixed breaker point eccentrically, and means carried by said distributor shaft and periodically engageable with said follower-for making and breaking said points.

7. A distributor construction as set forth in claim 6 wherein the means on the distributor shaft for engaging the follower comprises a plurality of arcuately spaced members positioned outwardly from the breaker points radially of the distributor body and rotating as a unit with the distributor shaft.

8. A distributor construction as set forth in claim 7 wherein the members comprise rollers.

9. A distributor construction comprising a distributor housing, a distributor shaft rotatable therein, a distributor plate mounted about said shaft in said housing and rotatable relative to said housing, said distributor shaft being rotatable relative to said breaker plate, a rocker arm, means rockably mounting said rocker arm on said plate, said rocker arm having a follower and carrying a relatively movable breaker point, a relatively fixed breaker point, means mounting said relatively fixed breaker point from said. platesubstantially in opposition to said relatively movable breaker point for eccentric rotation about the axis of said relatively movable point, a ratchet wheel for rotating said relatively fixed breaker point eccentrically from time to time, a pawl engaging said ratchet wheel for rotating said wheel from time to time, an arm pivotally mounted on said breaker plate and carrying said pawl, spring means biasing said arm to advance said pawl against said ratchet wheel to effect eccentric rotation of said relatively fixed breaker point, means for cocking and releasing said spring means from time to time, and means carried by and rotatable with said distributor shaft having a plurality of projections arcuately spaced for successive engagement with said follower to effect making and breaking of said breaker points.

10. A distributor construction as set forth in claim 9 wherein the means for cocking and releasing the spring means comprises a vacuum spark advance having a link simultaneously rocking said breaker plate relative to said housing and effecting pivoting movement of said arm against the action of its spring means.

11. A distributor construction as set forth in claim 10 and further including a centrifugal spark advance mechanism for advancing the means carrying the follower engaging members relative to the distributor shaft.

' 12. A distributor construction as set forth in claim 11 wherein the follower engaging-members comprise a plurality of rollers spaced outwardly of the breaker points radially of the distributor housing.

References Cited in the file of'this patent UNITED STATES PATENTS 1,061,613 Horold May 13, 1913 1,698,710 Bohlman Jan. 15, 1929 1,768,549 Fekete July 1, 1930 2,079,145 Arthur May 4, 1937 2,127,957 Ives et al Aug. 23, 1938 2,306,549 Louis Dec. 29, 1942 1,528,687 Brownlee et a1 Nov. 7, 1950 2,569,991 Hofrnann Oct. 2, 1951 2,605,368 Scott July 29, 1952