US3752140A

US3752140A - Ignition distributors

Info

Publication number: US3752140A
Application number: US00187270A
Authority: US
Inventors: A Rees; P Barr
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1970-10-30
Filing date: 1971-10-07
Publication date: 1973-08-14
Anticipated expiration: 1990-08-14
Also published as: AU449896B2; DE2153666A1; IT939000B; GB1354510A; AU3432371A; FR2110147A5; ES173642U; ES173642Y; BR7107238D0

Abstract

An ignition distributor including a hollow casing having journalled for rotation therein a cam shaft. A contact breaker assembly is mounted within the casing and is operable by rotation of the cam shaft, the contact breaker assembly including a carrier plate supporting the fixed and movable contacts of the contact breaker assembly. The carrier plate is mounted on a support member which carries the contact breaker assembly within the casing. The support member is formed from resilient wire and engages the inner surface of the casing at at least three angularly spaced points. The arrangement of the support member within the casing resists relative axial movement between the casing and the support member, and conveniently the arrangement includes a groove on the inner surface of the casing within which the wire seats.

Description

United States, Patent [1 1 Rees [ IGNITION DISTRIBUTORS [75] Inventor: Alfred Rees, Perry Barr, England [73] Assignee: Joseph Lucas (Industries) Limited,

Birmingham, England [22] Filed: Oct. 7, 1971 [21] Appl. No.: 187,270

[30] Foreign Application Priority Data [451 Aug. 14, 1973 1,068,813 9/1951 France 200/31 DP Primary Examiner-Laurence M. Goodridge Assistant Examiner-Cort Flint Att0rney-Holman & Stern 7 l ABSTRACT An ignition distributor including a hollow casing having journalled for rotation therein a cam shaft. A contact breaker assembly is mounted within the casing and is operable by rotation of the cam shaft, the contact breaker assembly including a carrier plate supporting the fixed and movable contacts of the contact breaker assembly. The carrier plate is mounted on a support member which carries the contact breaker assembly within the casing. The support member is formed from resilient wire and engages the inner surface of the easing at at least three angularly spaced points. The arrangement of the support member within the casing resists relative axial movement between the casing and the support member, and conveniently the arrangement includes a groove on the inner surface of the casing within which the wire seats.

8 Claims, 4 Drawing Figures PAIENTEU AUG 1 M973 3 752,140

Z7 Z5 26 F/G.4

INVENTOR ,wp d flees Mam/M ATTORNEYS IGNITION DISTRIBUTORS This invention relates to ignition distributors for internal combustion engine ignition systems.

An ignition distributor according to the invention includes a hollow casing, a cam shaft extending within the casing and rotatable therein, and a contact breaker assembly mounted within the casing and operable by rotation of said cam shaft, said contact breaker assembly including a carrier plate supporting the fixed and movable contacts of the assembly and a support member formed from resilient wire, the carrier plate being supported by the support member and the support member being shaped to engage said casing at at least three .angularly spaced points, the arrangement of the support member with the casing resisting relative axial movement between the casing and the support member.

Preferably, said support member engages the casing at four angularly spaced points.

Desirably, means is provided for aiding friction between the casing and the support member in resisting relative angular movement between the casing and the support member.

Conveniently the support member engages in a circumferential groove in the inner wall of the casing the walls of the groove aiding friction between the casing and the support member in resisting relative axial movement between the casing and the support member.

Conveniently the carrier plate is mounted for rotation on the support member about the axis of said cam shaft and is coupled to a vacuum operated advance capsule which in use varies the ignition timing of the distributor by moving the carrier plate angularly about the axis of the cam shaft.

Desirably said carrier plate is fixed to a hollow sleeve through which the cam shaft extends and said hollow sleeve carries a collar which is engaged at least three angularly spaced points by the support member, the sleeve being rotatable relative to the collar. Alternatively the collar is fixed relative to the sleeve and is rotatable relative to the support member.

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

FIG. 1 is a plan view of an ignition distributor with the cap thereof removed,

FIG. 2 is an inverted plan view of the distributor shown in FIG. 1 illustrating specifically the support member of the arrangement,

FIG. 3 is a sectional view on the line 33 in FIG. 1 with parts thereof omitted, and

FIG. 4 is an enlarged view of part of the arrangement shown in FIG. 3.

Referring to the drawings the distribuor includes a hollow cylindrical casing 11 supporting a cam shaft 12. The cam shaft 12 extends axially within the casing 11, and is mounted for rotation about its longitudinal axis within the casing. Supported within the casing 11 is a contact breaker assembly 13 including a carrier plate 14 having an angle plate pivotally mounted thereon, the angle plate being normally fixed relative to the plate 14 and supporting a fixed electrical contact 15. Pivotally mounted relative to the angle plate and the plate 14 about the pivotal axis of the angle plate is a moulded synthetic resin heel member 116 including a cam follower portion I7 engageable with the cam shaft 12. The heel member 16 carries a movable electrical contact 18, and pivotal movement of the heel member 16 moves the movable contact I8 into and out of engagement with the fixed contact 15. A leaf spring 19 is secured at one end to the heel member 16, and is anchored at its other end to the angle plate by means of an electrically insulating bracket, the spring 19 being stressed to urge the heel member 16 to pivot in a direction to engage the contact 18 with the contact 15, and to move the cam follower portion 17 towards the cam shaft 12. The plate M further carries a capacitor 21 which in use is electrically connected across the

contacts

15, 18, and the angle plate carries a felt pad which is impregnated with lubricating oil, and which engages the cam shaft 12 as the cam shaft 12 rotates.

The carrier plate 14 is supported within the casing 11, with the cam shaft 12 extending therethrough, by means of a spring wire support member 22. The spring wire support member 22 is formed from a length of spring steel wire of circular cross section. The spring steel wire is bent to the form of a triangle one apex of which is not completed. The three sides of the triangle are bowed inwardly, and the two completed

apices

22a, 22b are rounded. The unfinished apex is defined by the end portions of the wire each end portion being shaped to define rounded portions 22c, 22d respectively similar to the

apices

22a, 22b. The freeends of the length of wire are bent downwardly out of the plane of the re mainder of the support member 22.

The inner wall of the casing Ill is formed with a circumferential groove 23 the width of which is substantially equal to the diameter of wire constituting the support member 22. The support member 22 is secured to the casing 11 by flexing the support member 22 so it canvbe inserted into the open end of the casing, and then releasing the support member so that it springs back to its original shape, and in so doing engages the

regions

22a,22b,22c and 22d thereof in the groove 23. Thus these portions of the support member 22 are urged by the resilience of the member 22 into engagement with the base of the groove 23, and friction between the support member 22 and the casing 11 resists movement of the support member 22 relative to the casing. The side walls of the groove 23 further resist axial movement of the support member 22 relative to the casing 11, and a screw 24 is inserted through the casing and between the free ends of the length of wire constituting the member 22 to further resist angular movement of the support member 22 relative to the casing 11. Additionally the screw holds the free ends of the wire apart so as to minimise the risk of inadvertent disengagement of the member 22 from the groove 23. Moreover, the free ends of the member 22 can be employed to trap a terminal member in contact with the inner wall of the casing, the screw passing through a slot in the terminal which is connected by way of a lead to a further terminal anchored under a screw securing the earthed contact of the capacitor 21 to the plate 14.

Where no ignition timing adjustment is required within the distributor, the carrier plate 14 can be fixedly secured to the support member 22 in any convenient manner. However, where it is desired that ignition timing adjustment shall be provided within the distributor, then the carrier plate 14 is mounted on the support member 22 by way of a sleeve 25 secured to the carrier plate 14, and a collar 26 carried by the sleeve 25. The sleeve 25 is secured to the plate 14 so as to be coaxial 3 v with the aperture in the plate 14 through which the cam shaft 12 extends, the cam shaft 12 then of course extending through the sleeve 25. The sleeve 25 projects at one side from the plate 14,, and the projecting portion of the sleeve 25 carries an annular collar 26. The collar 26 surrounds the sleeve 25, and is rotatable relative thereto, the collar 26 being held against axial movement relative to the sleeve 25 by the plate 14, and an outwardly directed flange 25a at the free end of the sleeve 25. The outer surface of the collar 26 is provided with a circumferential groove of semi-circular cross section 27. The diameter of the collar 26 at the base of the groove 27 is slightly greater than the diameter of an imaginary circle which touches the three "inwardlycurved sides of the support member 22. The face of the flange 25a of the sleeve 25 is bevelled, and in order to mount the plate 14. on the support member 22 the sleeve 25 together with the collar 26 is inserted betwenn the three inwardly bowed sides of the support member 22. The plate 14 is urged towards the support member 22, and in so doing the sides of the support member 22 are flexed outwardly and the sleeve 25 enters between the sides of the member 22 until the groove 27 of the collar 26 is aligned with the member 22 whereupon the sides of the member 22 spring back toward their original positions and engage in'the groove 27. The sides of the member 22 grip the collar 26, and rotational movement of the plate 14 relative to the easing 11 is provided by rotation of the sleeve 25 relative to the collar 26. i

In use, the plate 14 is-coupled to a vacuum advance capsule carried by the casing ll, the vacuum advance capsule causing angular movement of the plate 14 about the axis of the cam shaft 12 to alter the ignition timing of the distributor The collar 27 can be formed from synthetic resin material, or metal, and moreover the wire which is used to form the support member 22 could also be of square, or rectangular cross section, the shape of the groove 27 in the collar 26 being varied accordingly.

If desired, the collar 26 can be fixed relative to the sleeve 25, and could even be integral with the sleeve 25, rotational movement of the plate 14 relative to the casing being permitted by rotation of the sleeve 25 relative to the member 22.

It will be appreciated that even if no vacuum advance capsule is to be provided the mounting of the plate 14 can be as described above means being provided to resist angular movement of theplate 14 relative to the casing. said means could conveniently be in the form of a screw threaded rod one end of which is coupled to the plate 14 and the other end of which extends through the casing and receives a nut the nut being held against movement other than rotational movement, and such rotational movement effecting adjustment of the ignition timing of the distributor.

We claim:

1. An ignition distributor for an internal combustion engine ignition system including a hollow casing, a cam shaft extending within the casing and rotatable therein, and a contact breaker assembly mounted within the casing and operable by rotation of the cam shaft, the contact breaker assembly including a carrier plate supporting the fixed and movable contacts of the assembly and a support member formed from resilient wire, the carrier plate being rotatably coupled to the support member by way of a hollow sleeve engaging both the carrier plate and the support member and through which said cam shaft extends, the carrier plate being rotatable about the axis of said cam shaft relative to the support member, and the support member being shaped to engage the casing at at least three angularly spaced points, and to engage the sleeve at at least three angularly spaced points, the engagement of the support member with the casing and said sleeve resisting relative axial movement between the support member and the casing and between the support member and the sleeve. I

2. A distributor as claimed in claim 1 wherein the support member engages the casing at four angularly spaced points.

3. A distributor as claimed in claim 1 wherein means is provided for aiding friction between the casing and the support member in resisting relative angular movement between the casing and the support member.

4. A distributor as claimedin claim 3 wherein the support member engages in a circumferential groove in the inner wall of the casing the walls of the groove aiding friction between the casing and the support member in resisting relative axial movement between the casing and the support member. 6

5. A distributor as claimed in claim 5 wherein the carrier plate is coupled to a vacuum operated advance capsule which in use can move the carrier plate relative to the casing angularly about the axis of the cam shaft so as to vary the ignition timing of the distributor.

6. A distributor as claimed in claim 1 wherein said carrier plate is fixed to said hollow sleeve through which the cam shaft extends, the hollow sleeve being supported by the support member and being rotatable relative thereto.

7. A distributor as claimed in claim 6 wherein the sleeve carries a collar which is engaged at least three angularly spaced points by the support member the sleeve being rotatable relative to the collar.

8. A distributor as claimed in claim 6 wherein the sleeve carries a collar which is engaged at least three angularly spaced points by the support member the collar being fixed relative to the sleeve and being rotatable relative to the support member.

Claims

1. An ignition distributor for an internal combustion engine ignition system including a hollow casing, a cam shaft extending within the casing and rotatable therein, and a contact breaker assembly mounted within the casing and operable by rotation of the cam shaft, the contact breaker assembly including a carrier plate supporting the fixed and movable contacts of the assembly and a support member formed from resilient wire, the carrier plate being rotatably coupled to the support member by way of a hollow sleeve engaging both the carrier plate and the support member and through which said cam shaft extends, the carrier plate being rotatable about the axis of said cam shaft relative to the support member, and the support member being shaped to engage the casing at at least three angularly spaced points, and to engage the sleeve at at least three angularly sPaced points, the engagement of the support member with the casing and said sleeve resisting relative axial movement between the support member and the casing and between the support member and the sleeve.

4. A distributor as claimed in claim 3 wherein the support member engages in a circumferential groove in the inner wall of the casing the walls of the groove aiding friction between the casing and the support member in resisting relative axial movement between the casing and the support member.