US3403665A - Ignition system for internal combustion engine and breaker point mechanism therefor - Google Patents

Description

R. E. PHELON 3,403,665 IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINE AND Oct. 1, 1968 BREAKER POINT MECHANISM THEREFOR 5 Sheets-Sheet 1 Filed April 18, 1966 IIII m a M M 4 11 2 3 3 O 0, n a 4? 0 2 n 0 4, 2 #4 1 :Q/ E m FIJI!!! w w INVENTOR. RUSSELL E. PHELO/V mu 5M R. E. PH ELON 3,403,665 IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINE AND Oct. 1, 1968 BREAKER POINT MECHANISM THEREFOR 5 heets-Sheet 2 Filed April 18 1966 6 .Illl 6 .5 x P 6 li't z United States Patent Otfice 3,403,665 Patented Oct. 1, 1968 ABSTRACT OF THE DISCLOSURE An internal combustion engine has an ignition system Which includes a spark plug and a capsulized breaker point mechanism threadably received by the engine housing for controlling the occurrence of a spark plug at the plug. A

' follower extends from the mechanism and engages a rotary cam on'the engine within the engine housing to operate the mechanism in response to rotation of the cam. The mechanism is threadably adjustable relative to the housing to move the follower generally toward and away from the cam whereby the occurrence of the spark may be altered relative to the angular position of the cam.

This invention relates to improvements in ignition systems for internal combustion engines and also relates to an improved breaker point mechanism for use in such a system and elsewhere.

At the outset it should be noted that the breaker point mechanism which forms a part of this invention is particularly well adapted for use in an ignition system of an internal combustion engine, and at present this is seen as its primary utility. Nevertheless, the mechanism may also be used as a circuit breaker or switch in many other applications and could for example be used as a limit switch. Therefore, although the mechanism has been described herein in connection with an ignition system, it should be understood that there is no intention to thereby limit the scope of the invention and that instead the invention is intended to extend to all uses to which the'mechanism may be put.

The general object of the invention is to provide an in1- proved ignition system for an internal combustion engine wherein all components of the system are or may be located externally of the engine so as to be directly and immediately accessible for servicing and replacement without the need for dismantling other engine parts or accessories.

Another object of the invention is to provide an improved internal combustion engine ignition system having a cam actuated breaker point mechanism wherein lubrication of the cam is provided by the internal engine lubrication system.

A further object of the invention is to provide a selfcontained breaker point mechanism, in the form of a capsule or cartridge, which can easily be mounted on a stationary part of an engine and which can be easily adjusted to vary the timing of the opening and closing of the points. In keeping with this object a further object of the invention is to provide a breaker point mechanism of the foregoing character wherein the state of adjustments necessary to obtain proper timing of the opening and closing of the points may be determined in a number of different ways, one of which ways involves the use of no special tools so when necessary a relatively good setting of the timing may be made by hand in the field.

A still further object of the invention is to provide a self-contained or cartridge-type breaker point mechanism wherein the breaker points are readily accessible for inspection and service.

Other objects and advantages of the invention will be apparent from the following description and from the drawings forming a part thereof.

The drawings show preferred embodiments of the invention and such embodiments will be described, but it will be understood that various changes may be made from the construction disclosed, and that the drawings and de scription are not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawings:

FIG. 1 is a side elevation of an internal combustion engine incorporating the features of the invention and shows a self-contained breaker point mechanism mounted on the engine housing in operating relationship to a breaker point actuating cam; a portion of the engine housing being broken away to show the cam and the cam engaging follower.

FIG. 2 is an end view of the internal combustion engine of FIG. 1.

FIG. 3 is a longitudinal half sectional view of the breaker point mechanism of FIG. 1.

F FIG. 4 is a sectional view taken along the line 4-4 of FIG. 5 is a sectional view taken along the line 5-5 of FIG. 3.

FIG. 6 is a longitudinal half sectional view of the cap assembly of the breaker point mechanism of FIG. 3 and shows the movable contact moved to a position external of the cap.

FIG. 7 is a longitudinal half sectional view of another breaker point mechanism embodying the invention.

FIG. 8 is a sectional view taken generally along the line 8-8 of FIG. 7 and shows the plunger in full.

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 7.

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 7.

FIG. 11 is a sectional view taken along the line 11-11 of FIG. 8.

Turning now to the drawings, first with particular reference to FIGS. 1 and 2, an exemplary internal combustion engine embodying the invention is indicated generally by the numeral 10. In most of its aspects the engine 10 is or may be of generally conventional construction and is comprised basically of a stationary structure and a number of moving parts such as a piston, connecting rod and crankshaft. The stationary structure may take various different forms and may be made up of a number of different parts, depending on the nature of the engine, and for convenience is herein referred to broadly as the engine housing, indicated by the reference numeral 12. The engine 10 is of the single cylinder spark ignition variety and includes a single spark plug 14 connected to the upper portion of the engine housing 12. The spark plug 14 is part of the ignition system of the engine 10 and associated with the spark plug, and also forming part of the ignition system, is a means including a breaker point mechanism 18 for supplying high-tension electrical impulses to the spark plug in proper timed relationship to the operation of the engine. This latter means may also take various different forms without departing from the broader aspects of the invention, and in the illustrated case comprises an electrical energy source or magneto described in more detail hereinafter.

Among other things, the engine housing 12 provides a chamber 16 in which a quantity of lubricant generally circulates when the engine is in operation for the purpose of lubricating t-he crankshaft and other moving parts of the engine. Located within the chamber 16, so as to be lubricated by the lubricant therein is a shaft 22 which rotates in timed relationship with the operation of the engine and which carries a breaker point operating cam 24. The breaker operating cam could in some instances be part of the engine crankshaft, however in the illustrated case the shaft 22 is a camshaft separate from the crankshaft. As viewed in FIG. 2 the chamber 16 at its right-hand side is defined by an end wall 20 of the engine housing. A shaft portion 26, which is also rotatable in timed relationship with the operation of the engine, extends outwardly from the engine housing, through and beyond the end wall 20, and in the illustrated embodiment comprises a part of the engine crankshaft.

The magneto used in the ignition system, in addition to the breaker mechanism 18, includes a flywheel rotor 28 which is fixed to the shaft portion 26 so as to be rotatable therewith. The rotor is formed mainly from a nonmagnetic material and has a central hub portion 30 and an annular outer peripheral flange. The radially outer or external face of the flange 32 is generally cylindrical in shape and embedded in the flange is a permanent magnet 34 and two associated pole pieces 36, 36.

The magneto also includes a stator adapted for attachment to the engine housing externally of the rotor 28. The stator comprises a magnetic core 38 which is preferably made from a stack of laminated sheet material so as to reduce eddy current and hysteresis losses. For securing the core 38 to the engine housing 20, a pair of elongated nonmagnetic spacing members 40, 40 are provided which are threaded into bosses on the housing, and which in turn threadably receive screws 42, 42 which pass through the core, to hold the core in outwardly spaced relationship with the housing. The core 38 has three generally parallel poles 44, 44 spaced angularly of the rotor, the three poles having arcuate radially inwardly facing end faces 46, 46 which are concentric with the axis of the shaft 26 and equidistant therefrom. A coil assembly 48 is received on the center stator pole 44 and includes primary and secondary windings which surround the center pole and which are made up of a different number of turns of conducting wire in accordance with conventional magneto practice. The primary coil is suitably grounded at one end and its other end is connected by means of an insulated conductor 50 to the breaker mechanism 18. The secondary coil is also suitably grounded at one end and at its other end is connected to an insulated conductor 52 which is in turn connected to the spark plug 14.

During rotation of the rotor, the pole pieces 36, 36 of the rotor move across the stator end faces 46, 46 and complete flux circuits through the stator, the flux passing through the center pole 46 suddenly reversing in direction at one point of rotor rotation to induce voltages in the primary and secondary coils in a manner well known in the art. The breaker point mechanism is timed to first close a circuit through the primary coil and to then break such circuit when the current flowing therethrough is at or near a maximum value, thereby generating a high voltage in the secondary coil which is connected with the spark plug 14.

The breaker point mechanism 18 is in the form of a cartridge or capsule separate from the remainder of the magneto and may be mounted at a convenient location remote from the magneto stator and rotor so as to permit ready access thereto. Preferably, and as shown, the breaker mechanism 18 is mounted on the engine housing 12 on the opposite side of the end wall 20 from the rotor 28 and includes a case or housing 54 which extends into the lubricant chamber 16. Projecting from the forward end of the case is an actuating member or cam follower 56 which is engageable with the cam 24 during at least a part of each revolution of the cam and which operates the breaker points of the breaker mechanism. The case 54 is generally cylindrical in shape and is provided with .an external thread for threadably engaging the engine housing, and a locknut 53 received on the external thread may be tightened to secure the case in any selected position relative to the housing. This mounting arrangement allows for easy adjustment of the engine timing in a manner that will be hereinafter further discussed, and it will also be apparent that the mechanism 18 may be readily removed from the engine and replaced by a like unit without disturbing other parts of the engine assembly.

Considering now the construction of the breaker point mechanism 18 in more detail, and referring to FIGS. 3 to 6, it will be noted that the case 54 iscomprised essentially of an inner part 55 and an outer part 57,.both of which are generally cylindrical tubular bodies. The inner part 55 is externally threaded on its outer surface to provide a thread for connecting the mechanism 18 to a correspondingly threaded supporting structure, in the manner of FIGS. 1 and 2, and the same thread is also usedfor connecting the outer part 57 to the inner part 55, the outer part 57 having an internally threaded portion 58 at its inner end which threadably engages the external thread of the part 55. Rearwardly of the threaded portion 58, as best seen in FIG. 6, the part 57 includes a bore portion 61 of generally circular cross section which in the assembled mechanism receives the rear end portion of the case part 55. Rearwardly of the bore portion 61 is another bore portion 63 of generally rectangular cross section, and between the bore portions 61 and 63 is a radial shoulder 65 which is engageable by the rear end of the inner case part 55 to limit the threading movement of the outer case part onto the inner case part and to allow the two parts to be tightly threaded onto one another to provide a relatively high resistance to disassembly. The inner case part is made of a metal having good electrical conductivity and has a cylindrical bore 59 extending completely therethrough. The actuating member or follower 56 has an enlarged diameter cylindrical guide portion 62 which is coaxially received in the forward portion of the bore and which is axially slidable and freely rotatable therein. At its forward end the part 55 is staked inwardly at a number of angularly spaced points 60, 60 to limit the forward movement of the follower and to retain it in assembled relationship with the case. The follower also includes a stem 64 which projects axially forwardly from the guide portion 62 and from the case part 55, and at the forward end of the stem 64 is a fiat circular cam engaging surface 66 arranged normal to the axis of the follower so that the follower will engage the cam in the same manner at all angular positions of the follower relative to the case part 55. The same effect may also be obtained with a rounded cam engaging surface, however a flat surface provides a line contact with the cam and is the presently preferred shape. Since the follower 56 is freely rotatable relative to the case part 55 about the axis of the bore 59 it has a tendency to axially rotate during operation because of normal engine vibration. The rotation causes the follower to assume various different positions of engagement with the cam 24 during operation and thereby reduces wear at the surface 66 to prolong the life of the breaker mechanism and to also maintain proper timing of the breaker point operation over a long period.

To provide for the making and breaking of an electrical circuit, two electrical contacts or breaker points 68 and 70 are contained in the case 54. The point 68 is fixed relative to the case and the other point 70 is moved into and out of engagement with the point 68 by the follower. The stationary point 68 is coaxially aligned with the bore 59 and has a rearwardly facing contact surface. This point 68 is located some distance forwardly from the rear end of the case part 55 and some distance rearwardly from the rear end of the follower 56, and is carried by a tab 72 struck inwardly from the part 55. The tab provides a means for electrically connecting the point 68 with the electrically conducting portion of the case for electrically grounding it to the engine housing. It will also be noted that a slot 73 is formed in the part 55 when the tab 72 is struck therefrom. This slot is located rearwardly of the tab 72 and radially, opposite to the breaker points so as to provide access to the points as will be hereinafter discussed.

Means for electrically insulating the moveable point from the electrically conducting portion of the case is provided by a cylindrical carrier 74 of electrical insulating material which is slidably received in the bore 59 rearwardly of the stationary contact 68 and which carries the movable contact 70. The carrier includes a cylindrical forwardly opening recess 76 partially defined by an annular wall 78 which is of considerably larger diameter than the point 70. The point 70 is located in the recess 76 and has a forwardly facing contact surface located slightly forwardly of the annular wall 78 to facilitate dressing by filing or the like when the point 70 is removed from the capsule. The location of the point 70 in the recess 76 provides a relatively long surface path between the point and the metallic case part 55 and thereby reduces the possibility of surface conduction therebetween.

To provide a means for movin the breaker point 70 in response to the reciprocal movement of the cam follower 56, the breaker mechanism 18 further includes a generally cylindrical sleeve 80 which is slidably received in the bore 59 between the guide portion 62 of the follower and the movable point carrier 74. An axially extending slot 82 in the sleeve 80 receives the tab 72 to permit axial reciprocating movement of the sleeve relative to the tab in response to the movement of the follower. As will be noted from FIG. 3, the sleeve 80 is of such a length that when the cam follower is in its forwardmost position and the movable point is in engagement with the stationary point 68 the sleeve is shorter than the space between the follower portion 62 and the carrier 74, the difference in length being represented by the clearance 86. This clearance or difference in length insures effective engagement between the breaker points when they are closed, and requires that the cam follower be displaced rearwardly a given distance from its forwardmost position before the breaker points are opened.

To close the rear end of the case 54, a disc-like metallic cap 92 is permanently attached to the outer case part 57 by having its marginal edge portion turned over an annular bead for-med on the rear end of the part 57. Located inside of the case part 57 between the cap 92 and the carrier 74 is a spring 94 of rectangular cross section made from a strip of electrically conducting spring material folded or curved upon itself in a serpentine manner, as shown in FIGS. 3 and 6, so as to act as a compression spring between the carrier and the cap. FIG. 6 shows the spring in its undeformed condition, and FIG. 3 shows it in its normal operating or assembled condition at which it is held in a compressed state so as to urge the carrier forwardly toward the stationary point 68.

An electrical terminal 96 is carried by the cap 92 and includes an inner part which extends through the cap and through the rear end of the spring 94. This inner part is swaged or otherwise deformed radially outwardly at its inner end to securely fasten the terminal and the spring to the cap. At the forward end of the spring, the spring and the point 70 are similarly fastened to the carrier 74 and to one another by a shank on the point 70 which passes through the carrier and the spring. The spring therefore serves both as a biasing means for urging the movable point 70 into engagement with the stationary contact 68 and as an electrically conducting means for establishing an electrical connection between the point 70 and terminal 96. If desired a helical coil spring could be used in place of the spring 94; however, such springs have a significant electrical inductance which sometimes produces problems when the springs are also used as conductors.

As previously noted, the case part 57 is separable from the case part 55.-Since the movable point carrier 74 and the bore within which it is received are both cylindrical, the carrier is free to rotate within the bore when the part 57 is threaded onto or off of the part 55. Thus the spring 94 may be securely and permanently attached to both the point 70 and to the terminal 96 prior to the final assembly of the mechanism to provide a low resistance circuit path therebetween. When the case part 57 is removed from the case part 55 the carrier 74 and its associated breaker point 70 are also removed therefrom and both breakerpoints are exposed for inspection or dressing. A file or other dressing tool may be inserted through the slot 73 to dress the stationary point also, as shown in FIG. 6, it should be noted that the spring 94, in its uncompressed state, is of a suflicient length to position the carrier 74 somewhat beyond the adjacent end of the case part 57, thereby making the movable point accessible for inspection and dressing.

As previously mentioned, lubrication for the cam engaging follower is or may be provided by the engine internal lubrication system. For this reason it may in some instances be desirable to provide a seal between the follower 56 and the forward end of the case part 55 to prevent the entry of excess oil into the breaker mechanism. Such a seal may take various different forms and in the illustrated case comprises a resilient generally tubular sleeve 98 made from an elastomeric oil resistant material such as neoprene. The sleeve 98 includes annular beads at both of its ends which respectively engage annular recesses in the follower 66 and in the forward end of the case part 55.

When the reciprocally movable follower 56 is in its forwardmost position, as it appears in FIG. 3, the carrier 74 under the influence of the spring 94 is urged forwardly to engage its breaker point 70 with the stationary breaker point 68. As the follower 56 is thereafter moved rearwardly or generally toward the movable point 70 by the cam 24 the rearward end of the sleeve engages the annular wall 78 of the carrier and moves the movable point axially rearwardly away from the fixed point 68 to break the electrical circuit therebetween. The cam 24 thereafter allows the follower to return to its forward position and the spring 94 returns the breaker point 70 to engagement with the point 68. The cycle of alternate breaker point engagement and separation continues in this manner throughout the operation of the engine.

The spring 94 may, if desired, be the only spring provided in the breaker point mechanism 18. When this is the case the spring, after the high point of the cam passes the follower, moves the carrier 74, the sleeve 80 and the follower 62 forwardly until the movement of the carrier is arrested by engagement of the breaker point 70 with the breaker point 68. Then, throughout the remaining fall and dwell portion of the cam movement, the sleeve 80 and the follower 62. are in an axially loose condition so that the follower may or may not engage the cam surface, the motion of the follower usually being such that the follower appears to bounce or dance onto and olf of the cam surface until the spring pressure is again picked up during the rise portion of the cam movement. This looseness of the follower 56 during the dwell movement of the cam is usually not objectionable, but, if desired, an additional spring, such as the helical compression spring shown at 75 in FIG. 3, may be placed in the sleeve 80 between the follower 56 and the tab 72 to urge the follower forwardly so that during the dwell portion of the cam movement the follower is held either against the surface of the cam or against the staked over portions 60, 60 of the case part 55. This arrangement assures that the same conditions prevail at each opening of the breaker points and eliminates any possibility of erratic operation due to the follower having different accelerations during different cycles of point opening.

Adjustment of the engine ignition timing is elfected by threadably rotating the mechanism 18 into or out of the engine housing to move thefollower 56 toward or away from the cam 24. Thus, the follower may be positioned relative to the cam to effect separation of the breaker points at various angular positions of the cam to alter the timing of the spark at the spark plug in relation to the piston position.

The engine timing is preferably set by means of a timing light and appropriate timing marks or indicators on the rotor and engine housing. The timing can, however, also be adjusted by a feeler gauge. When using a feeler gauge the engine is turned by hand until the piston is at the location where firing 'is to occur, as may usually be determined by aligning an indicator mark on the rotor with an indicator mark on the engine housing. The outer part 57 of the breaker mechanism case is then removed from the inner part 55 and the carrier 74 is held in place in the bore 56 of the part 55, and is pressed toward the fixed point 68, by hand. At the same time a feeler gauge, having the proper thickness, is inserted through the slot 73 in the case part 55 to test the gap between the points 68 and 70, and the inner case part 55 is threaded into or out of the engine housing until the breaker point gap matches-the thickness of the feeler gauge. In addition, the timing may also be set by a person in the field without the aid of a timing light, feeler gauge, or other special tool. In this instance the engine is also turned to bring it to the position where firing is desired. Thereafter the breaker mechanism case, with the outer part 57 fully assembled on the inner part 55, is first threaded out of and then into the engine housing. While doing this the proper position of adjustment can be fairly well determined by feel due to the resistance of the spring 94 which is first encountered at the point of adjustment where the movement of the point 70 from the point 68 is initiated.

In FIGS. 7 to is shown another capsule breaker point mechanism indicated generally at 100 for use with an engine, such as the engine 10 of FIGS. 1 and 2, and generally similar in outward appearance to the breaker point mechanism 18. Like the mechanism 18, the breaker point mechanism 100 has a case 102 which is generally cylindrical in shape and which includes an externally threaded portion for threadably engaging the engine housing and a cam follower 104 which projects from the forward end of the case to engage the cam 24 within the engine housing. However, the breaker point mechanism 100 differs from the mechanism of the aforedescribed embodiment in that it has a substantially permanently sealed case construction. It will also be evident that from the description which follows that the construction and arrangement of its parts differ somewhat from those of the mechanism 18.

Referring now particularly to FIGS. 7 and 8, it will be noted that the case 102 comprises an inner part 106 and an outer part 108 both of which are generally cylindrical tubular bodies. The part 106 is preferably made from metal having good electrical conductivity and at its forward end it is externally threaded to provide connec tion to a stationary part in a manner similar to that shown in FIGS. 1 and 2. A lock nut 110 received on the external thread is provided to secure the case in any selected position relative to the stationary part. Spaced rearwardly of the thread portion is an outwardly projecting annular flange 112 which includes a forwardly facing inclined annular surface 114. The part 106 also includes a generally cylindrical rear portion which projects rearwardly from the flange 112 and has a diameter somewhat smaller than the diameter of the forward or threaded portion.

The outer part 108 is adapted to 'be forced into an assembled position on the inner part 106 and for this reason it is preferably made from a somewhat resilient material of good electrically insulating quality. The part 108 has a forwardly opening generally cylindrical stepped bore which includes a forward bore portion 116 which receives the flange 112 in assembly therein. An intermediate bore portion 118 of somewhat smaller diameter receives the rear portion of the part 106. The part 108 also includes a rear bore portion 120 of still smaller diamter and between the bore portions 118 and'120 is a radial shoulder 122 which in the assembled mechanism is engageable by the rear end portion of the part106. At the forward end of the bore portion 116 is an inwardly projecting annular flange 124 which includes a forwardly facing forwardly inclined annular surface 126. In the assembled mechanism the flange 124 engages the part 106 forwardly of the flange 112 to'retain the two case parts in assembled relationship. The inclined surface 126 engages the flange 112 during assembly to expand the flange 124 and thereby facilitates the forceable assembly of the two case parts. In the assembled mechanism the rear edge of the flange 124 engages the inclined surface 114 tending to urge the parts 106 and 108 into tightly assembled relationship. At this point it should also be noted that the part 108 includes an axially elongated rib or flat 128 which projects radially inwardly from the wall of the bore portion 120. This rib cooperates with an associated slot in the part 106, to prevent relative angular movement between the two case parts in assembly in a manner which will be hereinafter further discussed.

The inner case part 106 has a stepped bore extending therethrough which includes a forward cylindrical bore portion 130 and a rear cylindrical bore portion 132 of somewhat smaller diameter. A radial shoulder 134 is defined intermediate the bore portions 130' and 132.

An electrically insulating material is preferably used to make the actuating member or cam follower 104 which has an enlarged diameter cylindrical guide portion 136 coaxially received in the bore portion 130 and axially slida ble therein. The follower 134 also includes a stern 138 which projects axially forwardly from the guide portion 136 and from the case part 106 and which has at its forward end a flat generally cylindrical cam engaging surface. Projecting coaxially rearwardly from the guide portion 136 is a cylindrical body portion 140 which extends through and slidably engages the bore portion 132 and which includes a rear end portion 144. Between the stern 138 and the body portion 140 is a radial shoulder 145.

To make and break an electrical circuit the mechanism 100 includes two electrical contacts or breaker points 146 and 148 which are contained within the case 102. The point 146 is fixed relative to the case and the other point 148 is moved into and out of engagement with the point 146 by the follower. The stationary point 146 which is coaxially aligned with the case 102 and which has a rearwardly facing contact surface is carried by a tab 150 which is struck inwardly from the part 106. An axially extending generally radially disposed slot 152 in the body portion 142 receives the tab 150 to permit axial reciprocating movement of the body portion relative to the tab in response to the movement of the follower. The tab 150 provides an electrical connection with the point 146 for electrically grounding it to an associated engine housing such as the housing 12 of FIGS. 1 and 2. It should also be noted that when the tab 150 is struck from the part 106 a slot 154 is formed in the part. This slot receives the rib or flat 128 of the outer case part and cooperates with the flat to prevent relative angular movement between the inner and outer parts of the case.

Actuating means for moving the movable point 148 in response to the movement of the follower is provided by the end portion 144 which carries the movable point. The point 148 is received within the slot 152 with its contact surface facing forwardly or toward the other point 146 and includes a rearwardly projecting shank portion 155 which extends coaxially through the end portion 144. The rear portion of the slot 152 is somewhat enlarged to accommodate a washer 156 which receives the point shank and provides additional support for the point 148. A similar washer 158 which surrounds the outer end of the shank 155 is disposed in an annular recess in the rear surface of the end portion 144.

Electrical connection with the movable point 148 is provided by a spring 160 which is preferably stamped in a spiral configuration from flat spring metal, as best shown in FIG. 11, and expanded to form a helical compression spring of conical shape. The upper end of the spring 160 is received on the point shank 155 which is swaged or otherwise deformed radially outwardly at its outer end to secure the spring in assembly with the point 148 and the end portion 144. The outer end of the spring 160 projects radially outwardly through the side wall of the outer case part 108 proximate the end wall thereof and provides an electrical terminal 162 to which is soldered or appropriately fastened an electrical conductor 163 which is molded or otherwise received in an axially outwardly enlarged portion of the part 108. Like the spring 94 of the aforedescribed embodiment the spring 160 may serve as both a biasing means for urging the movable point 148 into engagement with the stationary point 146 and as a means for establishing electrical connection from the movable point to the terminal 162.

If desired, the spring 160 may be the only spring provided in the breaker point mechanism 100. However, in the presently preferred embodiment of the invention an additional spring 164 is provided for urging the contacts into engagement. The spring 164 is received within the bore portion 130 between the shoulders 134 and 145 and surrounds the body portion 142.

To prevent the entry of oil into the breaker mechanism a seal member is preferably provided between the follower 104 and the forward end of the case part 106. Preferably and as shown the seal member comprises a somewhat washer-like oil resistant elastomeric sleeve 166 the outer end or peripheral edge of which is received in an annular recess in the forward end of the bore 130. The other end of the sleeve surrounds the stem 138. An annular locking ring 168 received in the recess forwardly of the sleeve retains the sleeve and also serves to retain the mechanism in assembly and to limit the forward travel of the follower 104.

When the mechanism 100 is used with an engine such as timing of the engine is preferably set by means of a timing light. However, the mechanism 100 may also be set by a person in the field without the aid of a timing light or other special tool in the manner previously described.

The invention claimed is:

1. In an internal combustion engine having a spark plug and a crankshaft, the combination comprising an engine housing having a chamber wherein a quantity of lubricant generally circulates for lubricating said crankshaft and other parts of said engine, means providing a cam located within said chamber rotatable in timed relationship with the operation of said engine and exposed to the lubricant in said chamber, a breaker point mechanism including a movable follower extending into said housing and engaging said cam for operating said mechanism in response to the rotation of said cam and a part located externally of said engine housing and theadably received by said engine housing so that said follower is adjustable toward and away from said cam as a result of rotating said case relative to said engine housing, an electrical energy source, and means connecting said electrical energy source to said breaker point mechanism and to said spark plugs so as to produce a spark at said spark plug the occurrence of Which is controlled by said breaker point mechanism and altered relative to the angular position of said cam by rotating said case relative to said engine housing.

2. The combination defined in claim 1 wherein said part is a case and said mechanism includes a movable breaker point and a stationary breaker point located in said case which movable point is moved into and out of engagement with said stationary point in response to movement of said follower relative to said case.

3. The combination defined in claim 2 further characterized by at least a portion of said case beingmade from an electrically conducting material, means electrically connecting said stationary point with the electrically conducting portion of said case and means electrically insulating said moveable point from said electrically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insulated from said electrically conducting portion, biasing means for urging said moveable point toward engagement with said stationary point, and electrically conducting means for providing electrical connection between said moveable point and said terminal.

4. A breaker point mechanism comprising a case having a threaded portion for use in connecting said mechanism to a cooperatively threaded supporting structure and at least a portion of which case is made from an electrically conducting material, an actuating member "having a follower portion exposed externally of said case and restrained by said case to reciprocating movement relative thereto, a stationary breaker point and a movable breaker point both located in said case and which movable point is movable into and out of engagement with said stationary point, means electrically connecting one said point with the electrically conducting portion of said case and means electrically insulating the other said point from said electrically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insulated from said electrically conducting portion, biasing means for urging said movable point toward engagement with said stationary point, electrically conducting means for providing electrical connection between said other point and said terminal, and actuating means for transmitting at least a part'of the reciprocating movement of said actuating member to one of the points to effect alternate engagement and separation of said points.

5. A breaker point mechanism as defined in claim 4 wherein said biasing means and said electrically conductingmeans comprise a single spring.

6. A breaker point mechanism as set forth in claim 4 wherein said case includes a tubular part having a bore and said threaded portion comprises external threads in the outer surface of said case coaxial with the axis of said bore, said actuating member including a guide portion slidably received in said bore for reciprocating movement relative thereto along the axis thereof, both of said points being located in said bore, said one point being said stationary point and said other point being said movable point.

7. A breaker point mechanism comprising a case having a generally cylindrical bore and at least a portion of which case is made from an electrically conducting material, a stationary breaker point and an movable point both located in said bore and which movable point is movable axially of said bore into and out of engagement with said stationary point, means electrically connecting said stationary point with the electrically conducting portion of said case and means electrically insulating said movable point from said electrically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insulated from said electrically conducting portion, biasing means for urging said movable point toward engagement with said stationary point, electrically conducting means for providing electrical connection between said movable point and said terminal, an actuating member having a follower portion exposed externally of said case and also having a generally cylindrical guide portion received in said bore on the opposite side of said stationary point from said movable point and restrained by said case to reciprocating sliding movement relative thereto along the axis of said bore, anda sleeve slidably received in said bore between said guide portion and said movable point for transmitting at least a part of the reciprocating movement of said actuating member to said movable point to effect alternate engagement and separation of said points, said sleeve being separate from said actuating member so that said actuating member may rotate relative to said case independently of said sleeve.

8. A breaker point mechanism'comprising a case having a bore and at least a portion of which case is made from an electrically conducting material, a stationary breaker point and a movable point both located in said bore and which movable point is movable axially of said bore into and out of engagement with said stationary point, biasing means for urging said movable point toward engagement with said stationary point, an actuating member having a guide portion received in said bore and restrained by said case to reciprocating sliding movement relative thereto along the axis of said bore, said actuating member including an end portion carrying said movable point and transmitting at least a part of the reciprocating movement of said guide portion thereto to effect alternate engagement and separation of said points, said actuating member also having a follower portion exposed externally of said case and located on the opposite side of said stationary point from said movable point, means electrically connecting said stationary point with the electrically conducting portion of said case and means electrically insulating said movable point from said electrically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insulated from said electrically conducting portion, and electrically conducting means for providing electrical connection between said movable point and said terminal.

9. A breaker point mechanism comprising a case having a bore and at least a portion of which case is made from an electrically conducting material, an actuating member having a follower portion projecting from one end of said case and also having a guide portion received in said bore and restrained by said case to reciprocating sliding movement relative thereto along the axis of said bore, an elastomeric sleeve having an end engaging said case adjacent said one end and having another end engaging said follower portion providing a seal between said case and said actuating member, a stationary breaker point and a movable breaker point both located in said bore and which movable point is movable axially of said bore into and out of engagement with said stationary point, means electrically connecting said stationary point with the electrically conducting portion of said case and means electrically insulating said movable point from said electr-ically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insulated from said electrically conducting portion, biasing means for urging said movable point toward engagement with said stationary point, electrically conducting means for providing electrical connection between said movable point and said terminal, and actuating means for transmitting at least a part of the reciprocating movement of said actuating member to said movable point to effect alternate engagement and separation of said points.

10. A breaker point mechanism comprising a case having a bore and at least a portion of which case is made from an electrically conducting material, a tab cut from the electrically conducting portion of said case and bent relative thereto so as to extend into said bore, a stationary breaker point and a movable point both located in said bore, said stationary point being carried by said tab, said movable point being movable axially of said bore into and out of engagement wtih said stationary point, biasing means for urging said movable point toward engagement with said stationary point, means electrically connecting said stationary point with the electrically conducting portion of said case and means electrically insulating said movable point from said electrically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insulated from said electrically conducting portion, electrically conducting means for providing electrical connection between said movable point and said terminal, an actuating member having a follower portion exposed externally of said case and also having a guide portion received in said bore and restrained by said case to reciprocating sliding movement relative thereto along the axis of said bore, and actuating means for transmitting at least a part of the reciprocating movement of said actuating member to said movable point to effect alternate engagement and separation of said points.

11. A breaker point mechanism comprising a case having a bore and at least a portion of which case is made from an electrically conducting material, said case including first and second tubular parts, said second part being connected at its inner end to one end of said first part in coaxial relation thereto and extending outwardly beyond said one end, an actuating member having a follower portion exposed externally of said case and also having a guide portion received in said bore and restrained by said case to reciprocating sliding movement relative thereto along the axis of said bore, a stationary breaker point and a movable breaker point both located in said bore and which movable point is movable axially of said bore into and out of engagement with said stationary point, means electrically connecting said stationary point with the electrical conducting portion of said case and means electrically insulating said movable point from said electrically conducting portion of said case, an electrical terminal fixed relative to said case and electrically insualted from said electrically conducting portion, a spring located in said second case part and having one end fixed thereto and including another end fixed to said movable point, said spring urging said movable point toward engagement with said stationary point and being electrically connected to said movable point, electrical conducting means for establishing electrical connection between said terminal and said spring, and actuating means for transmitting at least a part of the reciprocating movement of said actuating member tosaid movable point to effect alternate engagement and separation of said points.

12. A breaker point mechanism as defined in claim 11 wherein said second case part is disconnectably connected to said first part and wherein said spring has such an uncompressed length what when said second case part is removed from said first case part said spring positions said movable point externally of said second case part.

13. A breaker point mechanism as defined in claim 11 wherein said second case part is threadably connected to said first case part, and wherein said moveable point is mounted on a carrier made from an electrically insulating material and slidably received in said bore for axial reciprocation relative thereto, said carrier and the portion of said bore which receives said carrier being cylindrical in shape so as to allow said carrier to rotate relative to said first case part as said second case part is threaded onto or off of said first case part.

References Cited UNITED STATES PATENTS 2,157,666 5/1939 Jacobi 123l49 2,587,013 2/1952 Vogel 20030 2,605,753 8/1952 Madle 123146.5 2,684,394 7/1954 Guillermin 123146.5 2,982,805 5/1961 Glenday et al 123 l49 3,055,992 9/1962 Sargis 200-30 3,088,445 5/1963 Gardner 123-149 LAURENCE M. GOODRIDGE, Primary Examiner.

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