US3745272A

US3745272A - Contact breaker assembly with improved adjustable distributor mounting plate and locking plate means

Info

Publication number: US3745272A
Application number: US00200707A
Authority: US
Inventors: G Mosby
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1970-11-24
Filing date: 1971-11-22
Publication date: 1973-07-10
Anticipated expiration: 1990-07-10
Also published as: ES174844Y; ES174844U; IT945067B; AU3602971A; FR2115955A5; GB1364246A; AU461194B2; DE2157943A1

Abstract

A contact breaker assembly for use in the ignition system of an internal combustion engine includes a mounting plate arranged to mount the contact breaker assembly adjacent a rotatable cam. An angle plate is supported on one face of the mounting plate and the angle plate carries a fixed electrical contact and also pivotally supports an insulating heel member carrying a movable contact. The insulating heel member includes a cam follower engageable by the cam in use, and resilient means urges the heel member to pivot in a direction towards the cam so as to engage the movable contact with the fixed contact. A locking plate is engaged with the face of the mounting plate remote from the angle plate and a pivot post extends between the locking plate and the angle plate through the mounting plate, the pivot post positioning the angle plate for pivotal movement relative to the mounting plate about the axis of the heel member. First and second rotatable eccentric adjustment devices act between the angle plate and the mounting plate and are operable respectively to move the angle plate relative to the mounting plate in a manner to adjust the position of the cam follower of the heel member around the periphery of the cam and towards and away from the cam. Locking screws are provided to lock the angle plate against movement relative to the mounting plate.

Description

nited States Patent 1191 Mushy 1451 July 10,1973

1 1 CONTACT BREAKER ASSEMBLY WITH IMPROVED ADJUSTABLE DISTRIBUTOR MOUNTING PLATE AND LOCKING PLATE MEANS [75] lnventor: Geoffrey Ralph Mosby, Sutton Coldfield, England [73] Assignee: Joseph Lucas (Industries) Limited,

Birmingham, England [22] Filed: Nov. 22, 1971 [21] Appl. No.: 200,707

[30] Foreign Application Priority Data NOV. 24, 1970 Great Britain 55,722/70 52 US. (:1 .f. 200/31 A, 200/19 R, 200/31 DP 51 1111. c1. 110111 9/02 [58] Field of Search 200/19 R, 19 A, 30 R, 200/30 A, 31 DP, 31 A, 31

[56] References Cited UNITED STATES PATENTS 2,847,524 8/1958 Slick 200/30 A 2,854,534 9/1958 Beauclair 200/30 A 2,914,625 11/1959 Heveran 200/31 2,730,583 1/1956 Brunk 200/31 2,835,755 5/1958 Filko 200/31 x 3,510,609 5/1970 Cooksey 200/19 A Primary Examiner.l. R. Scott Attorney-Holman & Stern [5 7] ABSTRACT A contact breaker assembly for use in the ignition system of an internal combustion engine includes a mounting plate arranged to mount the contact breaker assembly adjacent a rotatable cam. An angle plate is supported on one face of the mounting plate and the angle plate carries a fixed electrical contact and also pivotally supports an insulating heel member carrying a movable contact. The insulating heel member includes a cam follower engageable by the cam in use, and resilient means urges the heel member to pivot in a direction towards the cam so as to engage the movable contact with the fixed contact. A locking plate is engaged with the face of the mounting plate remote from the angle plate and a pivot post extends between the locking plate and the angle plate through the mounting plate, the pivot post positioning the angle plate for pivotal movement relative'to the mounting plate about the axis of the heel member. First and second rotatable eccentric adjustment devices act between the angle plate and the mounting plate and are operable respectively to move the angle plate relative to the mounting plate in a manner to adjust the position of the cam follower of the heel member around the periphery of the cam and towards and away from the cam. Locking screws are provided to lock the angle plate against movement relative to the mounting plate.

10 Claims, 4 Drawing Figures Painted July 10, 1973 I 3,745,272

2 Shoots-Shut 1 Patented M 10, 1913 3,745,212

2 Slain-Shut 2 CONTACT BREAKER ASSEMBLY WITH IMPROVED ADJUSTABLE DISTRIBUTOR MOUNTING PLATE AND LOCKING PLATE MEANS This invention relates to a contact breaker assembly for use in the ignition system of an internal combustion engine.

An assembly according to the invention includes, a mounting plate arranged to mount the assembly adjacent a rotatable cam in use, an angle plate supported on one face of the mounting plate, the angle plate carrying a fixed electrical contact and having pivotally ri'iounted thereon an insulating heel member having a cam follower engageable by said cam in use, the heel member carrying a movable contact and the assembly having resilient means urging the heel member in a direction towards the cam to engage the movable contact with the fixed contact, a locking plate engaged with the other face of the mounting plate, a pivot post extending between the locking plate and the angle plate and mounting the-angle plate for pivotal movement about the pivotal axis of the heel member, a first adjustment device acting between the angle plate and the mounting plate and operable to move the angle plate and the locking plate relative to the mounting plate in a manner to adjust the position of the cam follower of the heel member around the periphery of the cam, and locking means operable to lock the angle plate against movement relative to the mounting plate.

Preferably the assembly includes a second adjustment device acting between the angle plate and the mounting plate and operable to move said angle plate about the axis of said pivot post relative to said locking plate and said mounting plate in a manner to move said cam follower towards or away from said cam.

Desirably means is provided whereby the locking plate can be fixed relative to the mounting plate at least during operation of the second adjustment device.

Conveniently said means is defined by a bolt or screw extending through a slot in the mounting plate and engaged with the locking plate.

Desirably said bolt or screw also constitutes said pivot post.

Preferably the first and second adjustment devices are defined by first and second members rotatably mounted on the angle plate and having eccentric portions engaged in respective apertures in the mounting plate.

Conveniently the first and second rotatable member have associated therewith respective locking means capable of locking the member respectively against rotation relative to the angle plate.

Preferably said mounting plate isannular and is arranged to encircle said cam in use, the mounting plate also carrying a second angle plate having pivotally mounted thereon second insulating heel member having a cam follower engageable by the cam and the second heel member carrying a second movable contact engageable with a second fixed contact carried by the second angle plate, the second angle plate being mounted on the mounting plate for pivotal movement relative thereto about the pivotal axis of the second heel member, and there being provided a third adjustment device operable to pivot the second angle plate relative to the mounting plate, and further locking means operable to fix the second angle plate relative to the mounting plate.

Desirably the second cam follower is displaced from the first mentioned cam follower by approximately around the mounting plate.

One example of the invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a plan view of a contact breaker assembly,

FIG. 2 is a sectional view on the line 22 in FIG. 1,

FIG. 3 is a sectional view on the line 33 in FIG. 1, and

FIG. 4 is a plan view of the mounting plate of the assembly.

Referring to the drawings, the assembly includes a mounting plate 11 which is arranged to be secured in the casing of a magneto of the ignition system of an internal combustion engine. It will be appreciated however that the assembly to be described is equally applicable to ignition systems utilizing ignition distributors, wherein the plate 11 will be arranged to be mounted within the casing of the ignition distributor. In either case the operating cam of the magneto, or ignition distributor will extend through a central, circular aperture 12 in the plate. Supported on one face of the plate 11 is a metal angle plate 13 upstanding from which is a hollow cylindrical sleeve 14 which supports an insulating heel member 15. The heel member 15 is pivotally mounted on the sleeve 14, and includes a cam follower 16 which is engageable with the cam surface of the rotatable cam of the magneto. Secured to the heel 15 is a movable electrical contact 17 the contact 17 being electrically connected to a conductive leaf spring 18 which at its end remote from the contact 17 is anchored to an insulating support 19 upstanding from the plate 13. The support 19 is arranged to receive terminals whereby electrical connections can be made to the movable contact 17. The heel member 15 is moulded in insulating material, and so insulates the moving contact 17 from the plate 13. The leaf spring 18 urges the heel member 15 to pivot about the sleeve 14in a direction to move the cam follower 16 towards the cam of the magneto, and to engage the moving contact 17 with a fixed contact 21 supported on, and electrically connected to a peg integral with the angle plate 13.

Engaged with the opposite surface of the mounting plate 11 is a locking plate 22 in the form of an elongated metal strip. In screw-threaded engagement with the plate 22, and extending through an arcuate slot 230 in the mounting plate 11 is a screw 23 having a cylindrical head 24 which engages the mounting plate 11 and which extends upwardly through a hole in the plate 13 and into the sleeve 14. The screw 23 serves the double function of acting as locking means capable of locking the plate 22 in position relative to the plate 11 and also acting as a pivot post about which the plate 13 can pivot relative to the plates 11, 22. As stated above, the slot 23a in the plate 11 through which the screw 23 extends, is arcuate, the slot being an are having its center of curvature coincident with the center of the circular aperture 12 in the plate 11.

Extending through the plates 11 and 13 are a pair of

locking screws

26 and 27 respectively. The heads of the

screws

26, 27 engage the surface of the plate 13, and the shanks of the screws 27 are in screw-threadedengagement with the plate 22. Thus when the

screws

26, 27 are tightened the

plates

22 and 13 are locked in position relative to the plate 11. The

screws

26, 27 pass through respective elongated slots in the plate 13, the elongated slots in the plate 13 extending generally radially with respect to the plate 11, and the

screws

26, 27 also extend through respective arcuate elongated

arcuate slots

26a, 27a in the plate 11, the

slots

26a, 27a having their centers of curvature coincident with the center of the aperture 12.

Mounted for rotation on the plate 13 are first and second adjusting

devices

28, 29 respectively. The

devices

28, 29 are identical, and so only the device 29 will be described. The device 29 includes a screw threaded shank 31 which extends through a clearance hole 32 in the plate 13. The plate 13 is formed with a recess in its lower surface within which a disc like portion 33 integral with the shank 31 is located. Extending downw ardly from the portion 33 is a cylindrical projection 34, the projection 34 being off-set from the axis of the shank 31 so as to constitute an eccentric. The portion 34 is engaged in an elongated arcuate slot 34a in the plate 11, the slot 34a in the plate 11 being disposed with its center of curvature coincident with the center of the aperture 12. Engaged with the portion of the shank 31 of the device 29, where the shank 31 projects from the upper surface of the plate 13 is a lock nut 35 which, when tightened against the plate 13 prevents rotational movement of the device 29 relative to the plate 13. The arrangement of the device 28 is substantially identical, with the exception that the arcuate slot 30 in the plate 11 into which the eccentric portion of the device 28 extends, is disposed generally radially of the plate 11.

It will be appreciated, that when the

screws

26, 27 are relaxed, and the screw 23 is tightened, then the plate 22 is fixed with respect to the plate 11, while the plate 13 can pivot about the axis of the screw 23, with respect to the plate 11. It will be noted that the axis of the screw 23 is coincident with the axis of pivotal movement of the heel member 15. With the parts in this condition, rotation of the shank of the device 29 causes the plate 13 to pivot about the axis of the screw 23 relative to the plate 11, so that the cam follower 16 is moved towards or away from the cam of the magneto. This operation permits adjustment of the maximum operating gap which can occur between the fixed contact 21 and the movable contact 17 as the heel member is reciprocated by rotation of the cam.

When the device 29 has been operated, and the desired operating gap between the

contacts

17, 21 has been achieved, the lock nut of the device 29 is tightened, to prevent further rotation of the device 29 relative to the plate 1.3. The screw 23 can then be released, whereupon the

plates

13 and 22 will be free to move arcuately relative to the plate 11 about a center of curvature coincident with the center of the aperture 12 in the plate 11. The setting of the operating gap of the

contacts

17, 21 will not of course be lost since the device 29 was locked in the desired position. Rotation of the device 28 causes such arcuate movement of the

plates

13 and 22, and thereby adjusts the position of the cam follower 16 around the periphery of the cam of the magneto. Such movement of course adjusts the timing of the opening and closing of the

contacts

17, 21 in relation to the rotation of the cam. When the

plates

13, 22 have been moved by the device 28 to give the required timing the lock nut of the device 28 is tightened to prevent further rotation of the device 28, and the

screws

23, 26, and 27 are tightened to lock the

plates

22, and 13, in position relative to the plate 11.

The plate 11 further serves to support a second angle plate 41 which is mounted on the plate 11 for pivotal movement about a pivot post 42 extending upwardly from the plate 11. The pivot post 42 is fixed with respect to the plate 11, and so the plate 41 cannot be moved arcuately on the plate 11, but can only pivot about the post 42. A further pair of locking

screws

43, 44 are provided for locking the plate 41 in position relative to the plate 11, and extending from the plate 41, co-extensive with the post 42, and surrounding the post 42 is a hollow .sleeve 45 upon which is pivotally mounted an insulating heel member 46. The heel member 46 includes a cam follower 47 which is engageable with the cam of the magneto, and further carries a movable contact 48. The movable contact is electrically connected to a conductive leaf spring 49 the end of which remote from the contact 48 is anchored to the plate 41 in a manner identical to that described with reference to the spring 18. A fixed contact 51 is supported on a tag integral with, and upstanding from the plate 41, and the contact 48 is movable into and out of engagement with the contact 51 in response to rotation of the cam of the magneto. An eccentric mechanism 52 similar in operation to the

devices

28, 29, although without the provision of a lock nut is provided for moving the plate 41 about the pivot post 42 to adjust the maximum operating gap of the

contacts

48, 51. 2

When it is desired to set the operating gap and timing of both sets of contacts of the arrangement described above, the contact gap of the contacts 38, 51 is first set by means of the eccentric device 52, and the plate 41 is then locked in position relative to the plate 11. The plate 11 is then moved relative to the cam of the magneto, to adjust the timing of the operation of the

contacts

51, 48. The operating gap of the

contacts

17, 21 is then set by means of the device 29, whereafter the lock nut of the device 29 is tightened to prevent alteration in the gap setting, and the position of the cam follower 16 relative to the cam follower 47 around the periphery of the cam is adjusted by means of the adjusting device 28.

It will be appreciated that the arrangement described above could be incorporated in a conventional ignition distributor of a road vehicle, either with or without the provision of the

contacts

48, 51 and the parts associated therewith.

I claim:

1. A contact breaker assembly for use in the ignition system of an internal combustion engine, including, a mounting plate arranged to be fixed adjacent a rotatable cam in use, an angle plate supported on one face of the mounting plate, the angle plate carrying a fixed electrical contact and having pivotally mounted thereon an insulating heel member having a cam follower engageable by said cam in use, the heel member carrying a movable contact and the assembly having resilient means urging the heel member in a direction towards the cam to engage the movable contact with the fixed contact, a locking plate engaged with the other face of the mounting plate, a pivot post extending between the locking plate and the angle plate and mounting the angle plate for pivotal movement relative to the mounting plate about the pivotal axis of the heel member, a first adjustment device acting between the angle plate and the mounting plate and operable to move the angle plate, the locking plate and the pivot post relative to the mounting plate in an arcuate path to adjust the position of the cam follower of the heel member around the periphery of the cam, first locking means operable to lock the locking plate and pivot post against movement relative to the locking plate, a second lockable adjustment device acting between the angle plate and the mounting plate and operable to move the angle plate relative to the mounting plate about the axis of the pivot post so that in use the operating gap of said fixed and movable contacts is adjusted, and, second locking means operable to lock the angle plate against movement relative to the mounting plate.

2. An assembly as claimed in claim 1 wherein said first locking means is defined by a screw extending through a slot in the mounting plate and engaging the locking plate.

3. An assembly as claimed in claim 2 wherein said screw also constitutes said pivot post.

4. An assembly as claimed in claim 1 wherein the first adjustment device is defined by a first member rotatably mounted on the angle plate and having an eccentric portion engaged in an aperture in the mounting plate.

5. Anassembly as claimed in claim 4 wherein said second adjustment device is defined by a second member rotatably mounted on the angle plate and having an eccentric portion'engaged in an aperture in the mounting plate.

6. An assembly as claimed in claim 5 wherein the first and second rotatable members have associated therewith respective locking means capable of locking the member respectively against rotation relative to the angle plate.

7. An assembly as claimed in claim 1 wherein said mounting plate is annular and is arranged to encircle said cam in use, the mounting plate also carrying a second angle plate having pivotally mounted thereon second insulating heel member having a cam follower engageable by the cam and the second heel member carrying a second movable contact engageable with a second fixed contact carried by the second angle plate, the second angle plate being mounted on the mounting plate for pivotal movement relative thereto about the pivotal axis of the second heel member, and there being provided a third adjustment device operable to pivot the second angle plate relative to the mounting plate, and further locking means operable to fix the second angle plate relative to the mounting plate.

8. An assembly as claimed in claim'7 wherein the second cam follower is displaced from the first mentioned cam follower by approximately around the mounting plate.

9. An ignition distributor utilizing a contact breaker assemble as claimed in claim 1.

10. A magneto utilizing a contact breaker assembly as claimed in claim 1.

Claims

1. A contact breaker assembly for use in the ignition system of an internal combustion engine, including, a mounting plate arranged to be fixed adjacent a rotatable cam in use, an angle plate supported on one face of said mounting plate, said angle plate carrying a fixed electrical contact and having pivotally mounted thereon an insulating heel member having a cam follower engageable by said cam in use, said heel member carrying a movable contact and said assembly having resilient means urging said heel member in a direction towards said cam to engage said movable contact with said fixed contact, a locking plate engaged with the other face of said mounting plate, a pivot post extending between said locking plate and said angle plate and mounting said angle plate for pivotal movement relative to said mounting plate about the pivotal axis of said heel member, a first adjustment device acting between said angle plate and said mounting plate and operable to move said angle plate, said locking plate and said pivot post relative to said mounting plate in an arcuate path to adjust the position of said cam follower of said heel member around the periphery of said cam, first locking means operable to lock said locking plate and said pivot post against movement relative to said locking plate, a second lockable adjustment device acting between said angle platE and said mounting plate and operable to move said angle plate relative to the mounting plate about the axis of said pivot post so that in use the operating gap of said fixed and movable contacts is adjusted, and, second locking means operable to lock said angle plate against movement relative to said mounting plate.

2. An assembly as claimed in claim 1 wherein said first locking means is defined by a screw extending through a slot in said mounting plate and engaging said locking plate.

4. An assembly as claimed in claim 1 wherein said first adjustment device is defined by a first member rotatably mounted on said angle plate and having an eccentric portion engaged in an aperture in said mounting plate.

5. An assembly as claimed in claim 4 wherein said second adjustment device is defined by a second member rotatably mounted on said angle plate and having an eccentric portion engaged in an aperture in said mounting plate.

6. An assembly as claimed in claim 5 wherein said first and second rotatable members have associated therewith respective locking means capable of locking said members respectively against rotation relative to said angle plate.

7. An assembly as claimed in claim 1 wherein said mounting plate is annular and is arranged to encircle said cam in use, said mounting plate also carrying a second angle plate having pivotally mounted thereon second insulating heel member having a cam follower engageable by said cam and the second heel member carrying a second movable contact engageable with a second fixed contact carried by the second angle plate, the second angle plate being mounted on the mounting plate for pivotal movement relative thereto about the pivotal axis of the second heel member, and there being provided a third adjustment device operable to pivot said second angle plate relative to said mounting plate, and further locking means operable to fix said second angle plate relative to said mounting plate.

8. An assembly as claimed in claim 7 wherein said second cam follower is displaced from said first mentioned cam follower by approximately 90* around said mounting plate.

9. A contact breaker assembly as set forth in claim 1 for use in an ignition distributor.

10. A contact breaker assembly as set forth in claim 1 for use in a magneto.