US2125367A

US2125367A - Ignition apparatus

Info

Publication number: US2125367A
Application number: US741226A
Authority: US
Inventors: James L Arthur; Dalphin L Hittle
Original assignee: General Motors Corp
Current assignee: Motors Liquidation Co
Priority date: 1934-08-24
Filing date: 1934-08-24
Publication date: 1938-08-02
Anticipated expiration: 1955-08-02

Description

` Aug. 2, 1938. J. l.. ARTHUR ET Al. 2,125,367

IGNITION APPARATUS original Filed Aug. 24, 1954 2 sheets-sheet 1 Aug.`2, 1938. J. l.. ARTHUR ET AL 2,125,367v

IGNITION APPARATUS Original Filed Aug. 24, 1954 2 Sheets-Sheet 2 y .af

Patented Aug. 2, 1938 UNITED STATES PATENT GFFICE IGNITION APPARATUS Application August 24, 1934, Serial No. 741,226 Renewed February 8, 1937 22 Claims.

This invention relates to ignition apparatus for internal combustion engines, and more particularly to an ignition circuit breaker the timing of which is controlled automatically in accordance with a function of the engine, for example in accordance with engine intake suction.

When controlling the timing of ignition in response to partial vacuum in the engine fuel inn take passage the practice has been to utilize a '10 vacuum-responsive displacement member, such as a piston or diaphragm, coupled with a rotatable circuit breaker plate so that the circuit interrupter will be angularly displaced with respect to the ignition timer cam, in response to i variations in vacuum or unbalanced atmospheric 125 rotation of the plate but not laterally with respect to this axis. The lateral support has heretofore been provided by a plain bearing.

It is one of the objects of the present invention to provide a ball bearing construction which 30 will support the circuit breaker plate laterally as well as axially with respect to its axis of rotation.

A further object is to take up lost motion, laterally as well as axially between the balls of the bearing and bearing races, wlnle at the same time '.35 minimizing interference due to friction.

A still further object is to prevent removal or axial displacement of the circuit breaker plate without introducing needless friction in rotary movement.

40 In the disclosed form of the present invention the outer race of the bearing is provided by an annular groove formed on the interior of the housing of the circuit interrupter or timer as by cutting the groove in the interior wall of the 45 cup, or by cutting the groove in the inner surface of a Vring fitted within the cup. The inner race is not continuous, but may be said to be an interrupted race provided by a series of pockets carried by the circuit breaker plate, each pocket 50 receiving a ball bearing. Each pocket is deiinecl by walls which diverge outwardly toward the outer race, so that each ball will engage the walls of its pocket and the outer race each at two points; thus each ball has a four-point engage- 55 ment with its races. A wall of at least one of (Cl. D- 19) the pockets is made of resilient metal, so that it will yieldingly urge the ball against the other confining wall of the pocket, and against the outer race.

To facilitate assembly and removal of the plate 5 assembly, vertical grooves are formed in the cup wall running from the edge to the outer ball race and so spaced as to coincide with the balls when placed in the inner race. There are preferably three substantially equi-distant balls so 10 that the act of urging one of the balls outwardly, by its resilient pocket wall against the outer race effects such a reaction upon the circuit breaker plate laterally as to cause all play, laterally as well as axially, to be taken up between the other 15 balls and their races. In eii'ect the circuit breaker plate is supported by three balls, each ball being yieldingly urged into a wedging engagement with four surfaces, namely, the two surfaces provided by the pocket for the ball and 20 the two surfaces provided by the outer race. In other words, the balls projecting across the space between the edge of the circuit breaker plate and the wall of the cup and into the races provided by these parts, acts as a lock that prevents removal of the circuit breaker plate from the cup until either the clamping screws are removed or the plate assembly is revolved so that the balls coincide with the vertical grooves. While the plate assembly is in its normal working position, the balls are displaced from the vertical grooves, so that lateral movement during that relation is not possible. The outer race, being formed so that it is concentric with respect to the ignition timer cam, the circuit breaker plate and its circuit interrupter, will be rotated axially of the cam. Hence, the circuit breaker will operate in the intended manner regardless of the adjusted position of the circuit breaker plate. Furthermore, the automatic adjustment of the plate by an instrument such as a device responsive to engine suction can be effected with the minimum of resistance due to friction.

A further object is to provide for mounting upon the ignition timer housing an automatic 5 instrument, such as a device responsive to engine suction, by means of a bracket so constructed and arranged that it will conceal the element which connects the device with the circuit breaker plate within the housing and Will thereore cover the opening in the housing through which this element extends.

A iurther object of the present invention is to provide a convenient means for varying the range of adjustment of the circuit breaker plate.

This is accomplished by providing a series oit spacer, or range limiting plates, any one of which is adapted to be interposed between the automatic instrument and the timer housing, and to form a part of the structural unit. Each range or spacer plate is provided with an opening through which passes the element connecting the instrument with the circuit breaker plate, the element having stops spaced a distance greater than the thickness of the plate and adapted respectively to bear against appropriate stops on opposite sides of the plate. Range plates of different thickness are provided for dierent ranges of adjustment of the circuit breaker plate.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a longitudinal sectional view of an ignition timer embodying the present invention, the section being substantially as indicated by the line and arrows I-I of Fig. 2.

Fig. 2 is a plan view of the timer with the cap and rotor removed, showing the vacuum unit, spacer, and attaching bracket in assembled relation.

Fig. 3 is a fragmentary sectional view taken substantially as indicated by the line and arrows 3-3 of Fig. 2.

Fig. 4 is a view illustrating one of the bearing balls and pocket therefor provided by the breaker plate, and is taken substantially in the direction of the arrow 4 of Fig. l.

Fig. 5 is a fragmentary sectional view taken substantially as indicated by the line and arrows 5-5 of Fig. 6.

Fig. 5a is a view similar to Fig. 5, with the range plate removed, for increasing the range of link movement.

Fig. 6 is a fragmentary sectional view taken substantially as indicated by the line and arrows 6-6 of Fig. 2.

Fig. 7 is a plan view of the bracket which supports the vacuum unit upon the ignition timer housing.

Fig. 8 is a View of the bracket taken substan-4 tially as indicated by the arrows 8 of Fig. '7.

Fig. 9 is a fragmentary sectional view taken substantially as indicated by the line and arrows 9 9 of Fig. 6.

Fig. 10 is a side View of a spacer plate used to determine the timing range effected by the vacuum unit.

Fig. 11 is a sectional view taken substantially as indicated by the line and arrows Ell-ll of Fig. 10.

Fig. 12 is a fragmentary view of a modification, also illustrating the removal grooves.

Fig. 13 is a detail view as indicated by the line and arrows l3-l3 of Fig. i2.

Fig. 14 is a detail view as indicated by the line and arrows Hip-ifi of Fig. l2.

20 designates a. timer cup or housing having a shank 2l by which it may be secured to the frame of the engine. The shank 2i carries a bearing 22 that rotatably supports the timer driving shaft 23 having a reduced portion 23a upon which is journaled a hollow shaft 2E providing a timer cam 2t and drivingly connected with shaft 23d by a speed-responsive device designated in its entirety by numeral 2d. As .is well known to those skilled in the art, the device 2d varies the angular relation between the shaft 23 and the cam 2@ in accordance with the speed of the engine. Cam 2li cooperates with the rubbing block lli of a circuit breaker lever 3l pivotally supported at 32 upon. the circuit breaker plate 5b' and carrying a contact that cooperates with a stationary contact grounded upon the breaker plate The rubbing block is urged toward the cam 22S, or the contact toward the contact by a leaf spring 35 xed at one end to the lever 3l and at the other to a conductor strap 3S that is attached by an ultraexible insulated wire 3l to an insulated terminal 38. An insulated wire t9 connects the strap 3G with a condenser il supported by a bracket di, that is secured to the plate and provides the grounded terminal of the condenser. In Fig. 2 only fragments oi the condenser and its. bracket it are shown. The electrical connection of the parts is completed by an ultra-flex ible insulated wire forming a ground lead between the breaker plate and the housing cup 2li. Screw devices 43 and lift respectively operate to connect the wire to the plate and cup.

The cam 25 supports and. drives a distributor rotor 45 carrying a distributor segment fl that moves past a circular' row of posts 4l and that is electrically connected with a leaf spring conductor di? carrying a button adapted to bear against a button 5E? carried by a central socket iii of a distributor cap 552.

A circuit breaker plate assembly is provided and as illustrated in Figs. l to 6 inclusive, constitutes a breaker plate E55 that is secured by screws to a sub-plate the plates and being so shaped as to provide three pockets substantially equiangularly spaced, each pocket receiving bearing ball. The three balls are designated by numerals 53, and bil respectively. Ball appears in Figs. 2 and 3, ball in Figs. l and Zl, and ball i553 in Fig. 2. The pockets for the balls 59 and are alike; hence the one for ball 59 will be described with reference to Figs. l. and fi. The plate ill provides a downwardly projecting lip ill, and the plate '35 with an upwardly projecting lip The lips 6l and t2 provide outwardly diverging surfaces t3 and et. respectively that engage the ball at spaced points. The surfaces and till provide in effect an inner race for 'the ball 55, the outer race being provided by an annular groove @El formed by diverging groove walls @iid and 55h on the interior oi the timer cup so that the groove will be located in a plane at right angles to the aXis of the shaft 23, and concentric therewith. An alternative 'form for the outer race is shown in Fig. 12, where a ring ttc is secured within the housing, and grooved as at As stated before the pocket ior the ball lill is the same as that for the ball 59.

A modified form of breaker plate assembly is illustrated in Figs. i2 and 13, where a plate 55a is peripherally grooved to form the diverging surfaces 630. and 60.-@ within which are disposed the balls, the pockets or interrupted race portions being defined by pins @i319 and 63o that pass through the edge of the plate 55a intersecting the said groove, and thus limit the extent of travel of the balls as do the pockets of the composite plate assembly 5b and 5l.

The pocket for the ball 58 is defined in the composite plate assembly by the downwardly extending lip 56 of the plate 5l, and by the upwardly extending portion of leaf spring member B8 attached by rivets Se to a bar lli integral with the plate 55. Similarly, one of the balls may be spring urged in the modied form of plate. The action of the spring 68 through its portion 61 is to urge the ball 58 against the lip 66 and against the outer race 65. The reaction resulting from urging the ball 58 against the outer race 65 is to urge the breaker plate 55 as a whole toward the

balls

59 and 60, and to cause each of those balls to be wedged in four different respects, namely, the ball 59 is wedged between

surfaces

63 and 64, between the surfaces 63 and 65h, between the surfaces 65a and 65h and between the

surfaces

64 and 65a. Therefore, each of the balls is confined between four tangent surfacesv so constructed and located that all lost motion both laterally and axially is taken up between the balls and the outer race and the interrupted inner race defined by the three spaced pockets. In other words, the breaker plate assembly has a threepoint support provided by the three

balls

58, 59 and 60.

One of these balls, the ball 58 is yieldingly urged against the outer race thereby causing the other two balls to be yieldingly urged against the outer race. This action is due to the spring 68 that takes up all lost-motion between the circuit breaker plate assembly and. the outer race, so that the plate is supported laterally without any play, while at the same time the plate assembly is permitted to be rotated concentrically with respect to the ignition timer cam and with the minimum of frictional resistance. This is very essential, because the circuit interrupter must cooperate with the cam in the intended manner regardless of the angular adjustment of the plate assembly with respect to the cam. Furthermore, since each of the

balls

58, 59 and 60 is confined yieldingly between angularly arranged surfaces due to the action of the spring 68, axial end play of the plate is taken up without introducing any undesirable friction. Consequently, the plate assembly is supported with substantially perfect rigidity, without introducing frictional resistance, such that would hinder its automatic control by a sensitive instrument, such as a device responsive to engine intake suction.

In order to facilitate insertion and removal of the breaker plate assembly with respect to the housing 28, three vertical grooves l0, il and l2 are formed in the inner wall of the housing so as to extend from the edge thereof to intersect the groove 65 forming the outer race. These vertical grooves are spaced for coincidence with the

balls

58, 59 and 60 respectively, but are so angularly displaced about the housing wall as to be out of registry with the respective balls while the plate assembly occupies any position within its range of normal angular movement. That is, while the plate assembly is coupled with the suction responsive device as illustrated in Figs. 2 and 6, movement of the plate assembly by the suction responsive device will never bring the balls into registry with the vertical grooves. Once the plate assembly is completely assembled with housing and suction responsive device, it will be necessary in order to withdraw the plate assembly from the housing, to disconnect the linkage between the suction device and the plate assembly. When this has been done, the plate assembly may be rotated to a point beyond the normal range of movement until the balls are in registry with the grooves, substantially as shown in Figs. 12 and 14, under which relation only is it possible to withdraw the breaker plate assembly. If that procedure is not followed, it then becomes necessary to separate the plates 55 and l5l Aby withdrawing the screws 56, or perhaps remove the screws 56 and take out the assembly part by part.

In order to insert the plate assembly, the balls are placed in their respective pockets, and arranged With respect to the housing 28, that the balls will coincide with the vertical grooves, whereupon the plate assembly may be inserted axially of the housing, with the balls 'traveling along the vertical grooves until they rest in the outer race 85. The plate assembly is then rotated to bring about the coupled relation of the plate assembly and the link l I2. This coupling causes the balls to move along the outer race and destroy their registry with vertical grooves.

The device responsive to engine intake suction hereinafter known as the vacuum-responsive unit will now be described with reference to Figs. 2 and 5 to 9. A exible diaphragm 88 is clamped at its peripheral edge between the flanges 8| and 82 of cup-shaped

members

83 and 84, respectively, the flange 82 being crimped around the flange 8| as indicated at 82a in Fig. 6. The member 84 is secured by bolts 85 and nuts 86 to a wall 9'! of a bracket 88, shown in detail in Figs. 7 and 8. Bracket 98 is secured by screws 8| passing through holes 92 in the bracket to the ignition timer housing 28. The part 84 may not bear directly against the wall 91 of the bracket 96, but against an intermediate spacing, range plate |08. As shown particularly in Fig. 9 the member 85 and the range plate |88 and the wall 97 of the part 98 are fixed together in a predetermined relation by providing the range plate |68 with projections |8| that mate with suitably spaced holes 88 in the member 84. The operation of providing the plate |88 with the projections 89 causes said plate |00 to be provided with recesses |82 in alignment with the projections |8| and adapted to receive suitably spaced projections 93 integral with the wall 91 of the bracket 98.

A rivet H8 passes through the diaphragm 88 and secures thereto a cup Washer and a ink H2 that passes through openings |53, IM and H5, provided respectively by the parts 84, lil@ and 98. The link i?. is provided with a hole at its right-hand end, as viewed in Fig. 6 or at its upper end as viewed in Fig. 2, which hole receives a stud l I6 attached to the plate 55. Link i?! is also provided with a neck il, wide enough to be received within the narrower portion Mea of the opening H4 of part |88, shown in Fig. l0, and within the narrower portion M5@ of the opening H5 in wall 9i of bracket 98. The neck il? of link H2 is defined by notches H8, shoulders H9 and shoulders 88. The shoulders H9 engage the right-hand side of the wall 91 of bracket 88, as viewed in Fig. 6, and the shoulders |28 may engage the left-hand side of the wall of plate |88 as viewed in the same figure, or the opposite side of the wall @l as viewed in Fig. 5a. The plate |58 may be one of a series of interchangeable plates of varying thickness. The thicker the plate the shorter the range of movement of link H2, and the thinner the plate the greater the range of movement. In fact no plate at all may be used, in which case the part 84 would be secured directly to the wall 5| of bracket 98, in which case the range of link movement would be marked by the shoulders i i8 and |28 engaging either side wall of the bracket part 9i as illustrated in Fig. 5a. It is not necessary to remove the nuts 86 entirely from the bolts 85, nor to disconnect the link ||2 from. the stud H5 which could be done only by removing the plate 55, in

order to remove one range plate E88 and to sub- 75 stitute another. All that is required is to loosen the nut suiliciently to disengage the parts 84, I and titi from interlocking relations shown in Fig. 9, whereupon the range plate i60 may be withdrawn. This withdrawal oi plate Iliil is permitted due to the fact that the plate |60 is not provided with round or closed holes for receiving the bolt shanks and link, but with notches |22, |23 and HM. Due to the fact that the opening Ht and notches |22! and |23 as not completely surrounded by metal, but open` out through the notches, the plate me may be passed between and taken from the interposed relation between the parts Erl and gli. The withdrawal of the range-limiting plate IDH of course permits the bolts |35 to remain in position. Preferably the bolts E5 are permanently and nonrotatably secured to the part @il so that they function as studs projecting through the holes provided :for them in the wall Sil oi the bracket QG. It is apparent that the bracket 9b conceals the link |12 and covers the opening i255 provided by the housing 20 for receiving the link.

The member 83 and the diaphragm il@ provide a suction chamber which is connected with the intake manifold of the engine by suitable piping, not shown, through the agency of a coupling I3!! threaded into a bushing I3! permanently attached to the part 83. Partial vacuum in the engine intake will eiiect an unbalance or atmospheric pressure acting upon the right-hand side ci the diaphragm 3E), thereby causing it to move toward the left in Fig. 6, thereby producing clockwise rotation oi the plate assembly. The direction or rotation of the cam 2B boing counterclockwise, the timing of the ignition will be advanced as suction increases. When suction decreases a spring |33 confined between the coupling lill and the washer i|| urges the diaphragm 8i) toward the right in Fig. 6 causing the plate 55 to be rotated counterclockwise to produce a more retarded spark.

While the embodiment ol the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other -forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

l. Ignition apparatus for an internal combustion engine comprising, in combination, a housing, a circuit breaker, a cam for operating the breaker, a breaker plate supporting the circuit breaker, said housing having an annular groove, means supporting the breaker plate including a plurality of balls, means spring urging the balls into the housing groove, and means for varying the angular relation between the cam and the breaker by rotating the plate in the groove.

2. Ignition apparatus for an internal combustion engine comprising, in combination, a timer housing having an annular groove, a circuit breaker, a cam for operating the breaker, a breaker plate, balls supporting the plate that operate in the groove, a second plate secured to the breaker plate, and having equally spaced pockets for the accommodation of the balls, spring means urging the balls into the housing groove, and means for varying the angular relation between the cam and the breaker by rotating the breaker plate on the ball support.

3. Ignition apparatus for an internal, combustion engine comprising, in combination, a timer housing having an annular groove, a circuit breaker, a cam for operating the breaker, a

breaker plate, balls seated in the groove formed in the distributor housing, a second plate fastened to the breaker plate and having deformed portions for each ball, a spring urging one of the balls into the groove whereby all of the balls are wedged between the deformed portion of the plate and the housing groove to eliminate axial and lateral lost motion.

4. Ignition apparatus for an internal combustion engine comprising, in combination, a timer housing having an annular groove, a circuit breaker, a cam for operating the breaker, a breaker plate, balls upon which the plate may turn, and operating in the housing groove, said breaker plate being superimposed upon a second plate having deformations for cooperation with said breaker plate to form races for the balls, means for urging at least one of. said balls into said grooves whereby the breaker plate will be secured against lateral movement.

5. Ignition apparatus for an internal combustion engine comprising, in combination, a timer housing having an annular groove, a circuit breaker, a cam for operating the breaker, a breaker plate, a series of balls operating in the groove for supporting the plate, a second plate secured to the underside or the breaker plate, said second plate having angularly deformed portions located along the side thereof and adjacent the breaker plate, thus forming tapering recesses for the reception of said balls, spring means urging the balls into the groove of the housing, thus preventing any lateral movement of` the breaker plate with respect to the cam axis.

6. Ignition device for an internal combustion engine comprising, in combination, an ignition timer housing having a groove in the inner wall, a breaker plate, a ball bearing interposed between the said housing and the breaker plate, and a spring connected at one end to the breaker plate, said spring urging and maintaining said ball in proper seating engagement with the housing groove whereby the breaker plate will be axially and laterally supported with the minimum or lost motion.

7. An ignition device for an internal combustion engine comprising, in combination, a housing, a breaker plate, a circuit interrupter sup ported by the breaker plate, a rotatable cam for operating said interrupter, a drive shaft for operinterposed between the housing and the breaker i plate, ball retainers provided by the breaker plate, spring means secured at one end to the breaker plate for urging the ball bearing into engagement with the housing groove, and means attached to the housing and connected with the breaker plate for rotating the breaker plate relative to the drive shaft and housing.

8. An ignition device for an internal combustion engine comprising, in combination, a housing having an inner Wall, said wall being grooved to provide an outer ball race, a plate Within said housing, having spaced recesses adjacent its outer a ball bearing in each recess, a breaker plate secured to the rst mentioned plate, and lips on the breaker plate htting upon the ball bearings carried by said lirst mentioned plate, said lips and recesses providing ball retainers carried by the plates, and each having a ball bearing which engages the annular wall groove of the housing and laterally supports the plate, a circuit interrupter on the plate, a member for operating said interrupter, and means extending into the housing and engaging the plate for rotatably adjusting the plate to vary the angular relation between the interrupter and its operating member.

9. An ignition device for an internal combustion engine comprising, in combination, a cupshaped housing having an annular wall provided with an inner groove, a breaker plate and a subplate having a shiftable support from the housing, said support including a plurality of ball bearings, pockets provided by cooperating deformations in the breaker plate and sub-plate for substantially enclosing a ball in each pocket, and spring means located in one of the pockets for forcing the balls outwardly to seat in the housing groove, and means securing the breaker plate to the sub-plate whereby the breaker plate is locked within the housing by the ball bearings and prevented from removal until the plates aie separated.

10. An ignition device for an internal combustion engine, comprising in combination, a cuplike housing, an engine operated shaft having a journal bearing in the housing, a circuit breaker adapted tc be operated by the shaft, a breaker plate, means supporting the plate independent of the shaft for rotation relative to the shaft and housing including ball bearings situated in spaced relation about the periphery of the plate, an outer race for the balls comprising a grooved member supported by the housing wall, and means including parts of the plate forming an inner race for the balls and for maintaining the balls within the outer race whereby the breaker plate is secured within the housing and maintained against axial and lateral movement relative to the shaft.

11. An ignition device for an internal combustion engine, comprising in combination, a cuplike housing, an engine operated shaft having a journal bearing in the housing, a circuit breaker adapted to be operated by the shaft, a breaker plate, ball bearings supporting the breaker plate independent of the shaft and having an outer race provided by the housing inner wall, a movable element for operating the breaker plate, means operatively connecting the movable element to the breaker plate, a sheet metal bracket supporting the movable element and secured to the housing, said connecting means having notched portions cooperating with the bracket for defining the range of movement of the breaker plate, and a spacer insertable between the bracket and chamber for varying the range of breaker plate movement.

l2. An ignition device for an internal combustion engine, comprising in combination, a cuplike housing, an engine operated shaft having a journal bearing in the housing, a circuit breaker adapted to be operated by the shaft, a breaker plate, ball bearings supporting the breaker plate independent of the shaft and having an outer race provided by the housing inner wall, a movable element, means operatively connecting the movable element to the breaker plate, and a sheet vmetal bracket supporting the movable element and secured to the housing so as to substantially enclose the operative connection between the movable element and breaker plate.

13. Ignition apparatus for an internal combustion engine comprising, in combination, a timer housing having an annular groove, a circuit breaker, a cam for operating the breaker, a plate assembly supporting the circuit breaker, balls operating in the housing groove upon which the plate assembly may turn, said plate assembly having circumferentially spaced race-ways for the balls, means for urging at least one of said balls into said grooves whereby the breaker plate will be secured against lateral movement.

14. Ignition apparatus for an internal combustion engine comprising, in combination, a timer housing having an annular groove, a circuit breaker, a cam for operating the breaker, means including a breaker plate for revolvably supporting the circuit breaker from the housing groove, balls disposed in spaced relation along the groove, means provided by the breaker plate forming race-ways for each of the balls and means for urging the balls into the housing groove and maintaining the revolvable support against displacement relative to the housing.

15. An ignition device for an internal combustion engine comprising, in combination, a housing, a breaker plate, a circuit interruptor supported by the breaker plate, a rotatable cam for operating said interrupter, a drive shaft for operating the cam, a bearing member adapted to be secured to the engine, and in which the drive shaft is journaled, said bearing member providing la mounting for the housing, a ball bearing support for the breaker plate comprising, an outer ball race supported from the housing wall, an inner ball race supporting the breaker plate, and a plurality of spaced balls having a bearing in both races.

16. In an ignition timer, a housing having a recess therein, friction reducing bearings extending into said recess, a retainer holding said bearings in spaced relation, a breaker plate, and means for supporting said breaker plate upon said bearings.

1'7. In an ignition timer, a housing having a bearing surface formed therein, friction reducing bearings in contact with said surface, a breaker plate, depending flanges carried by said plate,

and a channeled bearing surface formed upon said flanges to cooperate with said bearings.

18. In an ignition timer, a housing having a recess therein, friction reducing bearings extending into said recess, a retainer holding said bearings in spaced relation, a breaker plate, and flanges carried by said plate cooperating with said bearings to form a support for said plate.

19. In an ignition timer, a housing, an adjustable breaker plate, and friction reducing bearings Supporting the breaker plate laterally and axially from the housing side wall comprising, an outer raceway provided by a groove in the housing wall, an inner raceway provided at the periphery of the breaker plate, and balls disposed between the housing and plate and engaging both raceways.

20. In a ball bearing timer the combination comprising, a cylindrical housing wall internally grooved to provide a race way, a cam mounted on a shaft for rotation within the housing, a breaker plate providing an inner race way, a series of ball bearings disposed in both race ways for supporting the breaker plate from the housing wall, said cylindrical housing wall having vertical grooves in its inner surface extending from the edge of the wall to the race way whereby the ball bearings may be inserted in the race way of the breaker plate at the edge of the housing wall and thence depressed in assembled relation, so that the ball bearings pass down the vertical grooves to the outer race Way, said vertical grooves being circumferentially displaced from the operative position of the ball bearings, and means attached to the breaker plate for rotating the breaker plate relative to the housing wall, and for maintaining the ball bearings out of registry with the vertical grooves.

21. In an ignition timer the combination comprising, a housing having a cylindrical wall, said cylindrical wall having an internal peripheral groove spaced from the terminating edge of said housing, and a plurality of equally spaced vertical grooves leading from the edge of the housing to said peripheral groove, a breaker plate having a at bottom wall and flanges, said flanges providing circumferentially extending groove portions and adapted when disposed within the housing to confine ball bearings within the housing groove and the breaker plate grooves, and means for effecting limited rotation of the breaker plate relative to the housing wall and out of registry with the vertical grooves.

22. In a ball bearing timer the combination comprising, a cylindrical housing wall internally grooved to provide a race way, a cam mounted on a shaft for rotation Within the housing, a breaker plate providing an inner race Way, a series of ball bearings disposed in both race Ways for supporting the breaker plate from the housing wall, said cylindrical housing wall having a passage connecting with the outer race Way by which the ball bearings may be passed to position and be disposed between the race ways, said passage be ing angularly offset, from the ball position in the working assembly.

`JAMES L. ARTHUR. DALPHIN L. HITTLE.