Title:
IMPROVED CAM FOLLOWER ROLLER STRUCTURE FOR DISTRIBUTOR CONTACT BREAKER ARM
United States Patent 3575579
Abstract:
Ignition point means having a conventional multilobe cam. The cam follower comprises a plurality of independently rotatable discs of plastic such as nylon, so that the effects of nicks and wear on the cam follower are substantially eliminated.
US Patent References:
Combined timer and distributer
Lang - October 1920 - 1356532
Ignition device
Bowlus - August 1923 - 1464307
Circuit controller for semaphore signal mechanisms
Leake - September 1924 - 1507493
Eccentric control
Barbarou - November 1934 - 1982603
Electric switching device
Gachet et al. - July 1938 - 2124694
Combined timer and distributer
Lang - October 1920 - 1356532
Ignition device
Bowlus - August 1923 - 1464307
Circuit controller for semaphore signal mechanisms
Leake - September 1924 - 1507493
Eccentric control
Barbarou - November 1934 - 1982603
Electric switching device
Gachet et al. - July 1938 - 2124694
Application Number:
04/883894
Publication Date:
04/20/1971
Filing Date:
12/10/1969
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
74/569
International Classes:
H01R39/60; H01R39/00; H01H19/62; H01H3/00
Field of Search:
200/6 (B)1/ 200/21,22,27,30,31,33.2,37.1,38 (B)/ 200/38 (B)1/ 200/38 (C)/ 200/38 (C)1/ 200/153.11,153.12 74/567,569
US Patent References:
Primary Examiner:
Scott J. R.
Parent Case Data:
This application is a continuation-in-part of prior copending application, Ser. No. 616,910, filed Feb. 17, 1967 now abandoned.
Claims:
I claim
1. In a set of ignition points for internal combustion motors having a spring-loaded breaker arm secured at one end, having a contact point at its free end and having electrical insulator means intermediate these ends to engage the camshaft of said motor, an axle mounted on said arm, said insulator means comprising a plurality of rotatable plastic wheels rotatably mounted independently of each other on said axle adapted to engage said cam.
2. Apparatus as in claim 1 wherein said discs are removable and replaceable.
1. In a set of ignition points for internal combustion motors having a spring-loaded breaker arm secured at one end, having a contact point at its free end and having electrical insulator means intermediate these ends to engage the camshaft of said motor, an axle mounted on said arm, said insulator means comprising a plurality of rotatable plastic wheels rotatably mounted independently of each other on said axle adapted to engage said cam.
2. Apparatus as in claim 1 wherein said discs are removable and replaceable.
Description:
This invention relates to improved ignition points for automobiles. According to this invention, the conventional rubbing block of solid plastic material of a conventional set of ignition points is replaced by a rotatable element made of plastic electrical insulating material. Many species of the rotatable element are presented.
In the prior art, a rigid rubbing block is used on the spring-loaded lever arm to engage the lobes of the camshaft, to thereby open the points and thus interrupt the electrical current going to the various spark plugs.
The use of a plastic rubbing block has some serious disadvantages, such as excessive wear of the plastic especially if dust or grit gets into the distributor housing. This affects the timing of the engine. To reduce the heat obtained from the rubbing action of the plastic block on the rapidly rotating camshaft, it is conventional practice to apply a lubricant or grease on the cam surface. Such lubricants tend to evaporate because of the rubbing action of the block on the relatively hot camshaft, thereby affecting the spark obtained at the points.
It is an object of this invention to provide ignition points having no rubbing action between the ignition lever spring element and the camshaft.
It is another object to provide an ignition point set of long life, great efficiency and requiring substantially no maintenance.
It is another object of the invention to maintain accurate timing by substantially eliminating wear on the cam follower by making the cam follower of a plurality of independently rotatable discs or wheels.
Another object of the invention is to provide new and improved cam follower means comprising a plurality of wheels mounted on a bracket which is then mounted on the breaker arm.
These and other objects of this invention will become apparent upon reading the following descriptive disclosure taken in conjunction with the accompanying drawing of several illustrative embodiments thereof and in which:
FIG. 1 is a plan view of a set of ignition points showing a pair of plastic wheels as the engagement contact between the spring lever element or breaker arm and the camshaft.
FIG. 2 is a section view taken on line 2-2 of FIG. 1 and showing the pair of spaced-apart wheels secured to an axle fixed to the breaker arm.
FIG. 3 is a plan view of an embodiment using a plurality of plastic discs or wheels as the engagement contacts between the breaker arm and the camshaft and showing a manner of securing the discs in a curved breaker arm by use of a suitable bridge plate.
FIG. 4 is a section view taken on line 4-4 of FIG. 3.
FIG. 5 is a front view of another embodiment of the invention.
FIG. 6 is a top view of the embodiment of FIG. 5.
The electrical contact points are separated at the time a cam lobe engages a curved surface of a plastic or other electrical insulator disposed in the spring-loaded breaker lever arm. The curved surface is preferably a plurality of rotatable disc surfaces made rotatable by frictional contact with the surface of the cam of the camshaft.
The discs are constantly rotating in a random manner so that wear and consequent mistiming of the engine are substantially eliminated. It is impossible to wear grooves in the discs as in a single roller or pad.
However, if by any unforseen circumstance, one rotatable element of this invention becomes nonrotatable, the ignition points of this invention are still operable by the other discs for effecting an opening of the points by the action of a bearing curved surface upon an angular cam lobe of the camshaft.
As a solid roller, as in the prior art, rotates in contact with the multiedged cam, it will tend to develop wear spots or longitudinal grooves when the sharp cam edges contact the roller. In applicant's device, since the discs are free to rotate relative to each other, this groove wear will be randomly distributed among them so that nicks or grooves in one or more discs will be compensated for by the other discs which will have an integrating or averaging effect.
Referring to the drawings, FIG. 1 to 2 thereof, there is shown one form of this invention using a stationary axle having a pair of spaced-apart rotatable plastic wheels thereon. In this form of the invention, a conventional breaker arm 10, having a spring 11, is provided with a suitably located aperture 12. A metal axle 13 is passed through aperture 12 and is fixedly secured to the breaker arm 10 as by welding or other means. The integral axle 13 is preferably provided with opposed end sections 14 of reduced diameter and of a length sufficient to suitably pass through centrally apertured plastic wheels 15, 15' so as to extend beyond said wheels. The wheels 15, 15' are made of suitable plastic such as nylon or the like and are of a predetermined diameter to produce rapid and efficient opening of the electrical points 16. One manner of securing the respective wheels 15, 15' to the ends of the axle 13 is to peen over the axle extremities to from a flange 16'. Other conventional methods of securing the wheels 14 to axle 13 as by cotter pins, caps, etc. may be used to make the wheels or discs easily replaceable.
The wheels 15 ride on the cam 17 in such a manner that as the wheels pass over a cam lobe 18, the ignition points 16 are suitably opened to interrupt the current. If desired, bearings may be used on axle sections 14 to reduce wear.
FIGS. 3 and 4 illustrate an embodiment of this invention wherein the rotating elements are a plurality of plastic discs 30 disposed in a modified breaker arm 21. As shown in FIG. 3, the integral breaker arm 21 is provided with a suitably located integral semicircular section 22. The opposing sides of the breaker arm 21 are flat. A pair of flat bridge plates 23 are secured as by rivets 24 to the respective sides of the breaker arm 21, so as to bridge the semicircular section 22. The plastic discs 30 are rotatably disposed on an axle 25, the ends of the axle being press fitted or otherwise fixedly secured in a suitable aperture disposed in a bridge plate 23. The discs 30 are spaced from one another by use of spacers or washers 31. Such a separation of the discs 30 permits them to be air cooled at all times and if for any reason a disc 30 becomes nonrotatable, it will not effect the overall operation of the remaining discs which remain rotatable.
FIGS. 5 and 6 show another embodiment of the invention having a plurality of wheels 33, 34, etc. which are rotatably mounted by means of axle 35 on a bracket 36. The bracket is adapted to be slid over the end of the breaker arm 37 past the contact 38 and to be clamped onto the arm by means of the locking screw 39.
The wheels 33, etc. bear against the distributor cam 17, as illustrated in FIG. 6. They may be used in addition to the existing rubbing block 41 which rides on the cam, or they may be used without the rubbing block.
In the prior art, a rigid rubbing block is used on the spring-loaded lever arm to engage the lobes of the camshaft, to thereby open the points and thus interrupt the electrical current going to the various spark plugs.
The use of a plastic rubbing block has some serious disadvantages, such as excessive wear of the plastic especially if dust or grit gets into the distributor housing. This affects the timing of the engine. To reduce the heat obtained from the rubbing action of the plastic block on the rapidly rotating camshaft, it is conventional practice to apply a lubricant or grease on the cam surface. Such lubricants tend to evaporate because of the rubbing action of the block on the relatively hot camshaft, thereby affecting the spark obtained at the points.
It is an object of this invention to provide ignition points having no rubbing action between the ignition lever spring element and the camshaft.
It is another object to provide an ignition point set of long life, great efficiency and requiring substantially no maintenance.
It is another object of the invention to maintain accurate timing by substantially eliminating wear on the cam follower by making the cam follower of a plurality of independently rotatable discs or wheels.
Another object of the invention is to provide new and improved cam follower means comprising a plurality of wheels mounted on a bracket which is then mounted on the breaker arm.
These and other objects of this invention will become apparent upon reading the following descriptive disclosure taken in conjunction with the accompanying drawing of several illustrative embodiments thereof and in which:
FIG. 1 is a plan view of a set of ignition points showing a pair of plastic wheels as the engagement contact between the spring lever element or breaker arm and the camshaft.
FIG. 2 is a section view taken on line 2-2 of FIG. 1 and showing the pair of spaced-apart wheels secured to an axle fixed to the breaker arm.
FIG. 3 is a plan view of an embodiment using a plurality of plastic discs or wheels as the engagement contacts between the breaker arm and the camshaft and showing a manner of securing the discs in a curved breaker arm by use of a suitable bridge plate.
FIG. 4 is a section view taken on line 4-4 of FIG. 3.
FIG. 5 is a front view of another embodiment of the invention.
FIG. 6 is a top view of the embodiment of FIG. 5.
The electrical contact points are separated at the time a cam lobe engages a curved surface of a plastic or other electrical insulator disposed in the spring-loaded breaker lever arm. The curved surface is preferably a plurality of rotatable disc surfaces made rotatable by frictional contact with the surface of the cam of the camshaft.
The discs are constantly rotating in a random manner so that wear and consequent mistiming of the engine are substantially eliminated. It is impossible to wear grooves in the discs as in a single roller or pad.
However, if by any unforseen circumstance, one rotatable element of this invention becomes nonrotatable, the ignition points of this invention are still operable by the other discs for effecting an opening of the points by the action of a bearing curved surface upon an angular cam lobe of the camshaft.
As a solid roller, as in the prior art, rotates in contact with the multiedged cam, it will tend to develop wear spots or longitudinal grooves when the sharp cam edges contact the roller. In applicant's device, since the discs are free to rotate relative to each other, this groove wear will be randomly distributed among them so that nicks or grooves in one or more discs will be compensated for by the other discs which will have an integrating or averaging effect.
Referring to the drawings, FIG. 1 to 2 thereof, there is shown one form of this invention using a stationary axle having a pair of spaced-apart rotatable plastic wheels thereon. In this form of the invention, a conventional breaker arm 10, having a spring 11, is provided with a suitably located aperture 12. A metal axle 13 is passed through aperture 12 and is fixedly secured to the breaker arm 10 as by welding or other means. The integral axle 13 is preferably provided with opposed end sections 14 of reduced diameter and of a length sufficient to suitably pass through centrally apertured plastic wheels 15, 15' so as to extend beyond said wheels. The wheels 15, 15' are made of suitable plastic such as nylon or the like and are of a predetermined diameter to produce rapid and efficient opening of the electrical points 16. One manner of securing the respective wheels 15, 15' to the ends of the axle 13 is to peen over the axle extremities to from a flange 16'. Other conventional methods of securing the wheels 14 to axle 13 as by cotter pins, caps, etc. may be used to make the wheels or discs easily replaceable.
The wheels 15 ride on the cam 17 in such a manner that as the wheels pass over a cam lobe 18, the ignition points 16 are suitably opened to interrupt the current. If desired, bearings may be used on axle sections 14 to reduce wear.
FIGS. 3 and 4 illustrate an embodiment of this invention wherein the rotating elements are a plurality of plastic discs 30 disposed in a modified breaker arm 21. As shown in FIG. 3, the integral breaker arm 21 is provided with a suitably located integral semicircular section 22. The opposing sides of the breaker arm 21 are flat. A pair of flat bridge plates 23 are secured as by rivets 24 to the respective sides of the breaker arm 21, so as to bridge the semicircular section 22. The plastic discs 30 are rotatably disposed on an axle 25, the ends of the axle being press fitted or otherwise fixedly secured in a suitable aperture disposed in a bridge plate 23. The discs 30 are spaced from one another by use of spacers or washers 31. Such a separation of the discs 30 permits them to be air cooled at all times and if for any reason a disc 30 becomes nonrotatable, it will not effect the overall operation of the remaining discs which remain rotatable.
FIGS. 5 and 6 show another embodiment of the invention having a plurality of wheels 33, 34, etc. which are rotatably mounted by means of axle 35 on a bracket 36. The bracket is adapted to be slid over the end of the breaker arm 37 past the contact 38 and to be clamped onto the arm by means of the locking screw 39.
The wheels 33, etc. bear against the distributor cam 17, as illustrated in FIG. 6. They may be used in addition to the existing rubbing block 41 which rides on the cam, or they may be used without the rubbing block.