US3828579A

US3828579A - Centrifugal mechanism

Info

Publication number: US3828579A
Application number: US00323531A
Authority: US
Inventors: W Groom
Original assignee: Lucas Electrical Co Ltd
Current assignee: Lucas Electrical Co Ltd
Priority date: 1972-01-15
Filing date: 1973-01-15
Publication date: 1974-08-13
Anticipated expiration: 1991-08-13
Also published as: AU5077973A; JPS531423B2; DE2301715B2; BR7300325D0; CS166834B2; PL84941B1; YU33635B; DD103488A5; SU499827A3; DE2301715C3; AU473234B2; ZA73243B; GB1408152A; ES410635A1; DE2301715A1; HU166124B; IT976845B; JPS4878341A; AR213256A1; FR2168773A5

Abstract

A centrifugal mechanism, for an internal combustion engine ignition distributor, includes a driven shaft and a cam shaft coupled to the driven shaft and having its axis coextensive with the driven shaft axis. Secured to the cam shaft is a first plate, and secured to the driven shaft is a second plate generally parallel with the first plate. A control weight is pivotally mounted on the second plate for movement about an axis parallel to the axis of the driven shaft and the control weight engages a cam carried by the first plate. Positioned between the first and second plates is a moulded synthetic resin spacer which maintains the first and second plates spaced apart by predetermined distance. In addition, the spacer is engaged by the control weight in the rest position of the weight.

Description

Groom 1 Aug. 13, 1974 CENTRIFUGAL MECHANISM [75] inventor: Walter Joseph Groom, Sutton Coldfield, England [73] Assignee: Joseph Lucus (Electrical) Limited,

Birmingham, England 22 Filed: Jan. 15, 1973 21 Appl. No.: 323,531

[30] Foreign Application Priority Data Jan. 15. 1972 Great Britain 2021/72 [52] US. Cl. 64/25, 123/139 AP, 123/1465 [51] Int. Cl. Fl6d 5/00 [58] Field of Search 64/25; 123/1465, 139 AP [56] References Cited UNITED STATES PATENTS 2,009,935 7/1935 Malbry 64/25 2,060,556 11/1936 1 Davis, Jr. 64/25 3,045,458 7/1962 Campbell et al 64/25 25 let Primary Examiner-Samuel Scott Assistant Examiner-Randall Heald Attorney, Agent, or Firm-Holman & Stern [5 7] ABSTRACT A centrifugal mechanism, for an internal combustion engine ignition distributor, includes a driven shaft and a cam shaft coupled to the driven shaft and having its axis coextensive with the driven shaft axis. Secured to the cam shaft is a first plate, and secured to the driven shaft is a second plate generally parallel with the first plate. A control weight is pivotally mounted on the second plate for movement about an axis parallel to the axis of the driven shaft and the control weight engages a cam carried by the first plate. Positioned between the first and second plates is a moulded synthetic resin spacer which maintains the first and second plates spaced apart bypredetermined distance. In addition, the spacer is engaged by the control weight in the rest position of the weight.

2 Claims, 4 Drawing Figures PATENTED 31374 3.828.57'9

SHEET 1 BF 2 I CENTRIFUGAL MECHANISM This invention relates to a centrifugal mechanism for an internal combustion engine ignition distributor.

A centrifugal mechanism according to the invention includes, a driven shaft, a cam shaft, the cam shaft beingcoupled to the driven shaft and having its axis coextensive with the driven shaft axis, a first plate secured to the cam shaft, a second plate secured to the driven shaft and generally parallel with the first plate, a control weight pivotally mounted on one of the pair of plates constituted by the first plate and the second plate, for movement about an axis generally parallel to the driven shaft axis, a cam engaged by the control weight and carried by the other plate of said pair of plates, and, a moulded synthetic resinspacer maintaining the first and second plates spaced apart by a predetermined amount, thespacer also being engaged by the control weight in a rest position of the weight.

Preferably the mechanism includes a second control weightand a second cam engaged by the second control weight, the first and second control weights being positioned diametrically opposite one another on opposite sides ofthe driven shaft axis and both control weights engaging the spacer in their rest position.

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

FIG. 1 is a sectional view of a centrifugal mechanism for an internal combustion engine ignition distributor,

FlG. 2 is a plan view of a spacer shown in section in FIG. 1, but to an enlarged scale,

FIG. 3 is a sectional view on the line 33 in FIG. 2, and,

FIG. 4 is a plan view illustrating the rest position of the control weights of the centrifugal mechanism in relation to the spacer. 1

Referring to the drawings, the centrifugal mechanism in relation to the spacer.

Referring to the drawings, the centrifugal mechanism includes a driven shaft 11 having a portion 11a of reduccd diameter. The driven shaft 11 is in use journalled in the casing of the ignition distributor and driven by the internal combustion engine utilizing the distributor secured to the driven shaft 11 at the junction of the portion lla with the remainder of the shaft is a plate 12 the plate 12 extending transversely with respect-to the axis of the shaft 11. Rotatably mounted on the portion 11a of the shaft 11 is a hollow cam shaft 13 having, intermediate its ends, a portion 13a which defines a cam, and which,in use, is engaged by the cam follower of the contact breaker assembly of the ignition distributor. Secured to the end of the cam shaft 13 adjacent the plate 12 is a plate 14 which extends transversely relative to the axis of the cam shaft 13 and therefore extends parallel with the plate 12. Secured to the plate 14 by a pair of rivets '15 is a cam platel6. The rivets 15 secure the cam plate 16 to the plate 14 parallel thereto, and the plate 16 is formed with a centrally disposed aperture through which the portion 11a of the shaft 1.1extends. Upstanding from the plate 12 generally parallel with the axis of the shaft 11 are a pair of pivot posts 17. The pivot posts 17 are disposed diametrically opposite one another on opposite sides of the axis of the shaft 11 and pivotally mounted on each of the posts 17 is a control weight 18. The control weights 18 are substantially identical with one another and extend between the planes of the

plates

12 and 14. The control weights 18 each include a short limb 19 and a longer limb 21 and are arranged with their longer limbs lying on opposite sides of the axis of the shaft 11. As the shaft 11 is rotated then the weights 18 tend to pivot about the posts 17 as their longer limbs 21 move outwardly under the action of centrifugal force. The cam plate 16 is provided adjacent its ends respectively with a pair of cam surfaces 16a. The ends of the plate 16 extend respec tively between the limbs of the two control weights and the shorter limb 19 of each of the control weights includes a flat surface 22 which engages the respective cam surface of the cam plate 16. Thus as the weights 18 pivot about the posts 17 the surfaces 22 roll around their respective cam surface 16a and the cam surfaces are so shaped that the pivotal movement of the weights 18 moves the cam plate 16 and therefore the plate 14 and the shaft 13 angularly relative to the shaft 11 about the axis of the shaft 11. The rivets 15 securing the cam plate 16 to the plate 14 are extended, and project from the surface of the plate 14 remote from the plate 12 to define spring anchor posts 15a. A pair of tension springs 23 are provided for urging the assembly defined by the cam shaft 13, the plate 14 and the plate 16 to a rest position relative to the driven shaft 11 and plate 12. Each of the tension springs 23 secured at one end to an anchor post 15a, and at its other end to the adjacent pivot post 17. Thus the springs 23, together with the weights 18 and the cam plate 16 inter-connect the 30 driven shaft 11 and the cam shaft 13 so that the cam shaft 13 rotateswifh the driven shaft 11, and additionally, as the mechanism rotates and the weights 18 pivot about the posts 17 then the cam shaft 13 is moved angularly relative to the driven shaft.

Positioned between the cam plate 16 and the plate 12 is a moulded synthetic resin spacer 24. The spacer 24 is annular and encircles the portion 11a of the shaft 11. At one axial end the spacer 24 abuts the plate 12, while at its other opposite end the spacer 24 abuts the plate 16. Thus the spacer 24 serves to ensure that the plate 16, and therefore the plate 14 are spaced by a predetermined distance from the plate 12. The thickness of the spacer 24 is chosen so that the control weights 18, which have a greater thickness than the cam plate 16 are not impeded during their pivotal movement by making facial contact with the plate 14. The pivot posts 17 each include an integral collar spacing the respective control weight 18 from the plate 12. The spacer 24 which is shown diagrammatically in P10. 1, has a pair vide four peripheral recesses 27.

The spacer engages the cam plate 16 with the cam plate entering between the ribs 25 so that the ribs 25 provide a resilient abutment between the control weights l8 and the cam plate. The cam plate extends diametrically from the confines of the spacer between an end of each of the ribs 25 and the adjacent post 26, abutment of the cam plate with the end of a rib 25 or a post 26 resisting angular movement of the spacer relative to the cam plate, A space is left between the other end of each rib and the adjacent post 26 so that the same spacer can be utilized in either a clockwise or an anti-clockwise rotation mechanism, and similarly there are provided four rather than two recesses 27. The recesses 27 are provided to ensure that the limbs 22 of the weights 18 do not abut the spacer during pivoting movement of the weights.

The springs 23 urge the centrifugal mechanism to a rest position, and in the rest position projections provided on the longer limbs 21 of the control weights l8 engage the ribs 25 of the spacer 24. The dimensions of the mechanism are such that the springs 23 urge the weights 18 into contact with the spacer, and since the spacer is formed from synthetic resin material, and so has some inherent resilience, the mechanism is less inclined to rattle in use than would be a similar arrangement where the weights engage for example the steel shaft 11. As stated above the spacer spaces the cam plate 16 from the plate 12 and since the plate 16 moves angularly in use relative to the plate 12 the spacer acts also as a bearing. Conveniently the spacer is formed in a material such as Nylon which has the properties required for the various tasks of the spacer.

I claim:

l. A centrifugal mechanism, foran ignition distributor, including a driven shaft, a cam shaft, the cam shaft being coupled to the driven shaft and having its axis coextensive with the driven shaft axis, a first plate secured to the cam shaft, a second plate secured to the driven shaft and generally parallel with the first plate, a control weight pivotally mounted on one of the pair of plates constituted by the first plate and the second plate, for movement about an axis generally parallel to the driven shaft axis, a cam engaged by the control weight and carried by the other plate of said pair of plates, and, a moulded synthetic resin spacer maintaining the first and second plates spaced apart by a predetermined amount, the spacer also being engaged by the control weight in a rest position of the weight.

2. A centrifugal mechanism as claimed in claim 1 further including a second control weight and a second cam engaged by the second control weight, the first and second control weights being positioned diametrically opposite one another on opposite sides of the driven shaft axis and both control weights engaging the spacer in their rest position.

Claims

1. A centrifugal mechanism, for an ignition distributor, including a driven shaft, a cam shaft, the cam shaft being coupled to the driven shaft and having its axis co-extensive with the driven shaft axis, a first plate secured to the cam shaft, a second plate secured to the driven shaft and generally parallel with the first plate, a control weight pivotally mounted on one of the pair of plates constituted by the first plate and the second plate, for movement about an axis generally parallel to the driven shaft axis, a cam engaged by the control weight and carried by the other plate of said pair of plates, and, a moulded synthetic resin spacer maintaining the first and second plates spaced apart by a predetermined amount, the spacer also being engaged by the control weight in a rest position of the weight.