US3419689A

US3419689A - Ignition distrubutor structure

Info

Publication number: US3419689A
Application number: US635184A
Authority: US
Inventors: Steinke John Jacob
Original assignee: Steinke John Jacob
Current assignee: JOHN JACOB STEINKE
Priority date: 1967-05-01
Filing date: 1967-05-01
Publication date: 1968-12-31
Anticipated expiration: 1985-12-31

Description

Dec. 31, 1968 J. J. STEINKE 3,419,689

IGNITION DISTRIBUTOR STRUCTURE Filed May 1, 1967 INVENTOR United States Patent "ice 3,419,689 IGNITION DISTRUBUTOR STRUCTURE John Jacob Steinke, 206 Anderson Road, Watchung, NJ. 07060 Filed May 1, 1967, Ser. No. 635,184 7 Claims. (Cl. 200-19) ABSTRACT OF THE DISCLOSURE A motor vehicle ignition distributor having a pivot pin and a pair of spaced lugs located in spaced relationship to a rotatable cam mounted in said distributor, a rotatable breaker arm pivotally mounted on the pivot pin and bearing against the cam, through a rubbing block fixedly mounted on arm, the arm having a contact fixedly attached; a spring bearing against the rotatable breaker arm holding it against the rotating cam; a fixed spring contact assembly fixedly attached to one of the spaced lugs and electrically insulated therefrom, consisting of a spring steel element carrying an electrical contact point, the spring steel element being increasingly tensioned by the rotatable breaker arm during the contact phase and resting against an insulated stop in the return position.

This invention relates to ignition distributor structures and is particularly concerned with an improved breaker point assembly for an ignition distributor as used with ignition systems of internal combustion engines.

One of the objects of this invention is to provide a breaker point assembly for a distributor in an internal combustion engine, which maintains nearly constant timing and circuit closure duration irrespective of wear of the component parts.

Another object of this invention is to provide a breaker assembly, which needs no adjustment to maintain its operating characteristics during the life of the assembly.

A further object of this invention is to provide a breaker assembly, which exhibits an increasing closed circuit duration with increase in speed.

Still another object of this invention is to provide a breaker assembly, which induces a rapid circuit break in a reproducibly constant pattern and thereby reduces oxidation of the contact points.

In carrying out the above objects, it is another object of the present invention to provide a grounded contact arm, which is actuated through a hardened steel rubbing block by a hardened steel, lubricated, contoured cam, which minimizes wear and change of timing or closed circuit characteristics.

Another object of this invention, is to provide a simplified breaker mounting assembly, permissible by virtue of the fact that the breaker points do not require continued critical adjustment.

Another object of this invention is to provide a contoured, stepped cam, which causes point contact by outward pressure and opens the circuit as the high point of the cam leaves the rubbing block.

The action of the breaker assembly in this invention is opposite to the action of conventional assemblies. In conventional assemblies the contacts open gradually as the cam exerts an outward pressure on the rubbing blocks. Therefore the time of circuit break and the duration of circuit closure are dependent upon wear of the cam and of the rubbing block, wear of the distributor shaft bearing and oxidation of the contact points.

In the present assembly shown herein the contacts open after the rubbing block leaves the high point of the cam. This is accomplished by inertia effects and also by using a stronger spring holding the rotating point contact arm 3,419,689 Patented Dec. 31, 1968 against the cam relative to the spring in the fixed contact arm. The delay in contact point opening and the open circuit time is governed purely by the difference in spring tensions and by the contour of the cam.

Another difliculty encountered with conventional assemblies is bouncing of the contact points upon closure unless spring pressure is critically adjusted. In the present assembly the contact points close gradually, due to the stop provided for the fixed contact arm, and due to the gradually increasing slope of the cam face in the direction of rotation.

Conventional breaker assemblies require electrical insulating materials to insulate the breaker arm from the cam and from the point of rotation. These insulating materialsare subject to rapid wear, and hence to change in operating characteristics. In the present assembly the rotating point arm is grounded, and therefore employs hardened steel for the wearing parts.

Further objects and advantages of the present invention are apparent from the following description. Reference is made to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawing:

FIGURE 1 is a plan view of a distributor showing the breaker point assembly and the contoured cam according to the present invention.

FIGURE 2 is an exploded view in perspective showing the component parts of the breaker point assembly.

FIGURE 3 is a view along lines 3-3 in FIGURE 2 showing an elevation of the breaker mounting plate.

FIGURE 4 is an elevation view of the distributor cam.

In the drawings and in FIGURE 1 particularly, a breaker point assembly 24, according to the present invention, is shown installed in a distributor 17 of conventional design.

The breaker point assembly 24 is preferably secured by screw 23 to a plate 18 that is rotatable within the distributor in response to engine vacuum. The breaker point gap is adjustable by rotating breaker assembly 24 about pin 3, which pin engages hole in plate 18.

The rotatable plate 18 also supports condenser 16. Plate 18 is rotated within distributor 17 by means of lever 19, which connects to linkage from the vacuum diaphragm.

Spring washers

25 and 22 hold down plate 18 and provide electrical contact with distributor housing.

Stepped cam 21 rotates independently of plate 18 and is advanced in response to engine speed by means of a titgntrifugal advance mechanism located beneath the plate In FIGURE 2 rotatable breaker arm 1 is pivoted on pin 3, which is fixedly mounted on breaker mounting plate 24. Rotatable breaker arm 1 is actuated from cam 21 through rubbing block 2, and is held down on pin by means of washer 26 and spring clip 27. Breaker arm 1 is electrically grounded by conductor 15 and carries contact point 4.

The fixed spring breaker arm 5 is secured to breaker mounting plate 24 by means of bolt 10 and nut 12. Breaker arm 5, containing contact point 6, is electrically insulated from mounting plate :by means of Teflon or nylon insulators 7 and 9. Electrical current is provided to breaker arm 5 through conductor 20, as shown in FIGURE 1.

Point arm return spring 8 is also secured to mounting plate 24 by means of bolt 10 and nut 12. Return spring 8 is grounded to mounting plate 24, but is electrically insulated from breaker arm 5.

Movement of fixed spring breaker arm 5 is restricted by Teflon or nylon insulator 13, which insulator is connected to mounting plate 24 by means of nut 14.

In operation, cam 21 rotates clockwise at a speed one half of engine speed, causing the rotatable breaker arm 1 to close the primary coil circuit from conductor 20 through bolt 10, to fixed spring contact arm 5, to point contacts 6 and 4, to rotatable breaker arm 1, and hence to ground through conductor 15. The condenser 16- is placed between conductor 20 and ground 15 to minimize point arcing. When the rubbing block 2 leaves the high point of cam 21 the contact points 6 and 4 separate, breaking the circuit, due to the greater spring tension in return spring 8 over the spring tension in spring contact arm 5. When rotatable breaker arm 1 and rubbing block 2 reach the low point of cam 21, the contact points 4 and 6 open and the spring contact arm 5 is restricted by stop 13. The cycle is repeated for each cylinder in turn.

The performance is equally effective if the primary current is fed through the rotatable breaker arm 1 to contacts 4 and 6 through fixed spring contact arm 5 to ground. In this event the rotatable breaker arm must be electrically insulated from pivot pin 3 and from rotor 21, while the fixed spring arm 5 is grounded.

FIGURE 3 shows the projection of pin 3 below mounting plate 24, which pin engages a hole in plate 18. Prior to securing with screw 23, mounting plate 24 may be rotated about pin 3 in order to adjust point gap in the open position.

FIGURE 4 shows the cam 21 in elevation. The upper portion is cylindrical and slotted for mounting of the distributor rotor. The cam 21 is provided with lobes equal in number to the engine cylinders. If two sets of point assemblies are employed on the same cam, the number of lobes is halved. The lobe contour is gradually increased in radius in the direction of rotation to the high point. The trailing edge of the lobe is relieved to a negative angle or curve, to permit gradual return of the moveable contact arm 1 to the low point of the cam.

While embodiments of the present invention as herein disclosed constitute preferred forms, it shall be understood that other forms may be adopted.

What is claimed is as follows:

1. A breaker point assembly mounted on the vacuum advance plate in a distributor, comprising; a pivot pin and a pair of spaced lugs located in spaced relationship to a rotatable cam mounted in said distributor; a rotatable breaker arm pivotally mounted on the pivot pin and bearing against the cam, through a rubbing block fixedly mounted on arm, the arm having a contact point fixedly attached, which is part of the primary electrical circuit; a contoured cam with number of lobes equal to the number of engine cylinders, the cam causing an alternate opening and closing of the contact points; a spring bearing against the rotatable breaker arm holding it against the rotating cam; a fixed spring contact assembly fixedly attached to one of the spaced lugs and electrically insulated therefrom, consisting of a spring steel element carrying an electrical contact point, which forms a part of the electrical circuit mentioned above, the spring steel element being increasingly tensioned by the rotatable breaker arm during the contact phase and resting against an insulated stop in the return position, the insulated stop being fixedly mounted on the other spaced lug of the breaker assembly; the primary electrical circuit being electrically connected to the fixed contact assembly and the rotatable breaker arm being grounded to the distributor body.

2. A breaker point assembly as described in claim 1 adapted to be bodily installed as a unit on the vacuum advance plate of a distributor, comprising; a support plate apertured to receive a fastening means for securement to said vacuum advance plate, said support plate having a pivot pin and a pair of spaced lugs located in spaced relationship to the rotatable cam mounted in the distributor, the support plate being rotatable about the axis of the pivot pin by engagement with a hole in the vacuum advance plate, serving as a means of adjusting the point 4 gap prior to securing the supportplate with the holddown screw.

3. In a breaker point assembly and distributor as described in claim 1, a cam with a stepped contour, which acts against the rubbing block of the rotatable breaker arm causing a gradual closure of the point gap, tensioning of the spring steel element of the fixed contact assembly, and sudden opening of the point gap at the step in the cam contour; the step in the cam being relieved to a negative angle or curve allowing the breaker arm to return to the low point of cam in a controlled path and hence reducing the impact on the cam.

4. In a breaker point assembly as described in claim 1, a spring holding the rotatable point arm against the cam, which spring has a tension greater than the tension in the spring steel element of the fixed contact assembly, causing the point arms to separate immediately the pressure of the cam on the rubbing block of the rotatable contact arm is relieved.

5. Two breaker point assemblies as described in claim 1, the rotatable contact arms bearing against a contoured cam with number of lobes one half the number of engine cylinders causing an opening and closing of the contact points; the primary electrical circuit being electrically connected to the fixed contact assemblies, and the rotatable breaker arms being grounded to the distributor body.

6. A breaker point assembly mounted on the vacuum advance plate in a distributor, comprising; a pivot pin and a pair of spaced lugs located in spaced relationship to a rotatable cam mounted in said distributor; a rotatable breaker arm pivotally mounted on the pivot pin and in sulated therefrom, bearing against the cam through a rubbing block fixedly mounted on arm and insulated therefrom, the arm having a contact point fixedly attached, which is part of the primary electrical circuit; a contoured cam with number of lobes equal to the number of engine cylinders, the cam causing an alternate opening and closing of the contact points; a spring bearing against the rotatable breaker arm holding it against the rotating cam, which spring is electrical insulated from the distributor body; a fixed contact assembly fixedly attached to one of the spaced lugs, consisting of a spring steel element carrying an electrical contact point, which forms a part of the electrical circuit mentioned above, the spring steel element being tensioned by the rotatable breaker arm during the contact phase and resting against a grounded stop in the return position; the primary electrical circuit being electrically connected to the rotatable breaker arm and the fixed contact assembly being grounded to the distributor body.

7. Two breaker point assemblies as described in claim 6, the rotatable contact arms bearing against a contoured cam, being insulated therefrom, the cam having one half the number of lobes as engine cylinders and causing the opening and closing of contact points; the primary electrical circuit being electrically connected to the rotatable contact arms and the fixed spring contact assemblies being grounded.

References Cited UNITED STATES PATENTS 1,255,846' 2/1916 Appel 200-30 2,133,413 10/1938 Arthur 200-19 2,938,085 5/1960 Andrews 200-27 FOREIGN PATENTS 765,242 1/1957 Great Britain.

ROBERT K. SCHAEFER, Primary Examiner.

H. BURKS, Assistanlt Examiner.

U.S. Cl. X.R. 200-27