US2685623A - Ignition circuit breaker - Google Patents

Description

H. L. FUSTON IGNITION CIRCUIT BREAKER Aug. 3, 1954 Filed Aug. 19, 1950 INVENTOR: HOWARD L. FUSTON Patented Aug. 3, 1954 UNITED STATES PATENT OFFICE IGNITION CIRCUIT BREAKER Howard L. Fuston, Oak Park, Ill. Application August 19, 1950, Serial No. 180,431

8 Claims.

This invention relates in general to an ignition circuit breaker and is more particularly described as a removable and a replaceable ignition breaker point assembly which can be applied to and removed from the timing mechanism of an internal combustion engine Without materially changing the timing positions of the parts and by maintaining the time relation substantially constant at all times durin the operation and use of the circuit breaker.

Circuit breakers now commonly used with internal combustion engines have a cam with the desired number of cam lobes firmly attached near the end of the cam shaft and connected to turn with the cam shaft. On another part of the distributor or magneto, an arm is pivoted intermediate its ends so that when one end of the arm is engaged by the cam a contact on the other end of the arm is separated from a stationary ignition contact. The arm oscillated by the cam is held against the stationary contact by means of a spring which tends to hold one end of the arm in the path of the cam and the contact at the other end of the arm in engagement with the stationary contact. The amount the oscillating arm is raised or lifted determines the distance the ignition contacts are separated and this distance is called the point gap.

Each time the ignition point or contacts are separated, spark is furnished to the combustion chamber of an engine cylinder. The delivery of the spark must be at the proper time to ignite the fuel in the combustion chamber and to correctly time the breaking or separation of the igni on points, called timing the ignition breaker, requires highly trained labor, and often times, very ex pensive technical machines.

' When these i nition points are damaged and must be replaced with new points, the old points are removed from the parts mentioned and new points are inserted, then properly spaced or the point gap set, and correct timing of the circuit breaker obtained. As these points are installed upon a part which does not always remain at the same distance from the center of the cam or from the center of the cam shaft, it is a highly technical job to obtain proper gap setting when new points are installed and to correctly time the circuit breaker.

Most of the distributors and magnetos are located on the internal combustion engine to which they are applied in such a location that it is practical to try to replace damaged points withoutnrst removing the circuit breaker from the engine.

An important object of this invention is therefore to provide a mechanical factory point assembly which has the point gap properly set at the factory so that this factory point assembly may be applied after the damaged points are removed without the need of highly skilled labor.

Another object of this invention is to provide a point assembly in which the timing of the circuit breaker is not changed, when it is desired to replace damaged ignition points, thereby eliminating the necessity of using highly skilled labor and often times expensive technical machinery for retiming the circuit breaker.

Another object of the invention is to provide a point assembly that has desired ignition point gap set at factory which may be quickly and easily installed in a distributor or magneto, thereby saving much labor and providing for the sav ing of time that the engine is out of operation.

A further object of the invention is to provide a factory connected assembly of parts and points which may often be used when old points are damaged, to replace the damaged points without the necessity of removing the distributor or magneto from the engine, the replacement point assembly being so designed, that it may be easily and quickly applied to and removed from the dis tributor whenever it is necessary to replace the damaged points in a circuit breaker without the need of highly trained technical labor or expensive technical machines.

Other objects of the invention will appear in. the specification and will be apparent from the accompanying drawings in which,

Fig. l is a perspective View of an ignition breaker point assembly in accordance with this invention;

Fig. 2 is a top plan view of the point assembly structure shown in Fig. l; and

Fig. 3 is a sectional view of the construction shown in Fig. 1.

Referring now more particularly to the drawings, a cam ii! is attached by a stud or screw at or near the top of a cam shaft 22 which rotated by an engine to which it is applied in a well known manner. The cam usually has a number of projections or lobes depending upon the number of cylinders of the engine and other operating conditions.

Surrounding the cam is a plate I l having a pivot it extending upwardly therefrom upon which a lever i8 is mounted for oscillation. One end 23 of the lever extends toward and in the path of the cam lobes, and the other arm 22 of the lever carries an ignition point contact 24 adapted to make engagement with a stationary ignition point contact 26 mounted upon an adjustable bracket 23 secured to the plate i l as by a stud 33 and electrically insulated therefrom by an insulating pad 32 so that a conductor 34 may extend from the contact 26 or the supporting bracket thereof. The lever is pressed by a spring 36 so that the two contacts 24 and 26 are normally in engagement and one arm of the lever is in the path of the cam lobes and the contacts are separated each time this arm is engaged by one of the cam lobes and the contacts are returned to engaging position by the spring 36 after the high points of the cams are past. when the two ignition points are held together by the spring, a current flows through these points and a spark occurs when the oscillating arm point which is grounded is actuated by one of the'rotating cam lobes.

The plate it may be actuated slightly forward or rearward by mechanical device whose power is generally but not necessarily derived from the vacuum pressure of'the internal combustion engine. In all circuit breakers now commonly used, the ignition points are located on a plate or a part which is not snugly fit around the cam shaft, so that the plate or part is not forced to remain always at the same distance from the center of the cam shaft. When the cam shaft and the part in question are originally installed in a distributor or magneto, great care is used to have the cam shaft and the cam rotate truly in the exact center of the plate or part in question so that the points located on this part are so positioned that all the cam lobes will separate the oscillating lever the exact distance it is necessary to separate the points to give the best spark to the combustion chamber of the engine cylinder, and at the exact time the spark is to reach the fuel in the cylinder.

If the cam shaft does not continue to run true or if the bushings or sleeves become worn, then the untrue movement of the cam shaft causes a cam lobe to oscillate the lever 18 too early or too late to result in the delivery of a spark to the combustion chamber of an engine at the exact time desired, thereby adversely affecting the eiliciency and power of the engine. The same thing occurs if for any reason the plate It in question does not always remain in the correct desired location because of the relative adjustment of the plate in a circuit breaker casing 40 in which it is normally mounted. If the plate is moved in the casing relative to the center of the cam shaft if, the cam lobes will move the lever It a different distance than it is intended to be moved, thereby correspondingly varying the spark caused by the breaking of the ignition points.

The present invention provides means for correcting and overcoming these objections by mounting the supporting plate [4 not in connection with the circuit breaker casing as has been the practic heretofore, but by connecting a collar 42 at the center of the plate l 4, the collar having an opening 44 which fits snugly around the cam shaft, thereby forcing it to remain the same distance from the cam shaft at all times regardless of whether or not the cam shaft pursues a true course .of travel. attached to the plate M and forces the plate I4 to run true with the cam shaft (or upon a circular portion of the cam itself, if desired) at all times.

To provide means for permitting this part to The collar is firmly Ji l) follow any untrue movement of the cam shaft and yet not to rotate with the cam shaft, a floating type of mounting is used which comprises a timing bracket 45 attached by fastening bolts or screws 43 to the breaker casing 40 with a projection 50 extending inwardly therefrom. This projection is in the form of a narrow tongue with parallel sides adapted to be seated in a slot 52 extending inwardly from the outer edge of the plate 14 and preferably in a radial direction therein. This timing bracket may be made in various shapes so long as it will allow free movement in or out and up or down of the plate [4 but will not allow the plate 14 to rotate with the cam shaft.

With this construction, the plate It may be raised or lowered and it may be moved relatively inward or outward with respect to the casing, but since it is mounted upon the cam shaft (or upon the cam itself), the relative spacing of the lever 18 and its contact arm 2!: is always the same and the separation of the breaker points it and 25 remains constant.

After the timing bracket 46 is properly located in the ignition breaker assembly and the point gaps properly set at the factory or by expert means on the plate Id, the entire point gap assembly (plate and points) be quickly removed when the ignition pcints are damaged or worn and a new assembly (plate and points) can be quickly and easi y installed. without disturbing the original timing of the circuit breaker in any manner, as timing bracket is not disturbed after originally properly installed, and this replacement of damaged. points does not require highly trained skilled labor or expensive technical equipment, it is simply the substitution of one point assembly for another one of the same kind.

With this construction, a greatly improved manner of making the circuit breaker for internal combustion engines is provided greatly reducing the time and expense of replacing and installing damaged ignition points in a circuit breaker, thereby permitting an engine to be more quickly returned to useful service and also saving time and expensive technical equipment which is ordinarily required to replace damaged ignition points and retime the circuit breaker. This equipment is particularly designed and intended for use either as original equipment upon the ignition breakers now commonly used or as an attachment which may be applied thereto. While it requires skilled technical labor to apply an ignition breaker point assembly consisting of the circuit breaker mounting plate and the timing bracket mounting to an existing circuit breaker casing installation, the subsequent connection or substitution of another point assembly requires no skilled labor, only the removal of the first assembly applied in the casing and the substitution of another similar point assembly thereto.

While one design of this construction has thus been described in some detail, it should be regarded as an illustration or example rather than as a limitation or restriction of the invention, since various changes in the construction, cornbination and arrangement of parts may be made without departing from the spirit and scope of the invention.

I claim:

1. An ignition circuit breaker comprising a rotatable cam shaft, a cam fixed to and movable with the shaft and an ignition breaker point assembly comprising a plate and means mounting it directly upon but not rotatable with the cam shaft, the point assembly comprising a lever pivot on the plate having an arm to engage the cam and another arm moved by the lever when it is engaged by the cam, a breaker point mounted upon the plate and the last named arm and. adapted to be separated when the other arm of the lever is engaged by the cam, and slidably connected means between the plate and the casing for holding the plate against rotation with respect to the cam shaft upon which it is mounted.

2. In an ignition circuit breaker point assembly, a plate having a central opening and means mounting the plate to fit directly and closely upon a cam shaft rotatable therein, a slot extending inwardly from the outer periphery of the plate, a bracket for attachment to the inside of a circuit breaker casing having a tongue extending into the slot of the plate for preventing the rotation of the plate with respect to the casing but permitting a relative up and down and in and out movement.

3. In an ignition circuit breaker point assembly, a removable plate having a central mounting adapted to fit directly and closely upon a cam shaft to which the assembly is applied, a contact lever pivotally mounted upon the plate to engage a circuit breaker cam, fixed and movable contact points supported by the plate and lever respectively, and a timing bracket adapted to be secured to the inside of a circuit breaker casing and having a projection extending radially therefrom toward a cam shaft in the casing, the plate having a slot extending inwardly from the periphery and adapted to receive the projection from the bracket closely therein to permit a relatively inward and outwardly and up and down movement of the plate relative to the cam 01" cam shaft but preventing a relative rotation of the plate with respect to the cam or cam shaft.

4. In an ignition circuit breaker point assembly, a plate adapted to fit within a circuit breaker casing having a central mounting to fit directly and closely upon a cam shaft rotatable therein, a plate having a radial slot with parallel sides extending inwardly from the outer periphery thereof, and a firmly anchored timing bracket comprising a portion fixed to the inside of the casing with a projection adapted to extend from the inner periphery of the ignition breaker casing and fit closely in the slot of the plate and the bracket and its slot in fixed timing relation with respect to the cam, and an ignition breaker point assembly mounted upon the plate and comprising an operating lever and fixed and movable contact points.

5. In an ignition breaker, a rotatable cam shaft and a cam fixed thereon, a circuit breaker casing, a point assembly plate carrying ignition breaker means actuated by the cam, the plate having a central opening mounted directly upon the cam shaft to cause the point assembly plate to always follow the movement of the cam shaft and the cam, and means connecting the plate and the casing for limited sliding movement but preventing the plate from rotating with the cam shaft, thereby maintaining an even amount of separation of the contact points even though the cam shaft and the cam may fail to run true within the breaker housing and thereby prolong the services of the circuit breaker.

6. A circuit breaker construction, in accordance with claim 5, in which the point assembly plate has a slot in the periphery and the casing has a projection which extends into the slot permitting free movement of the point assembly plate with any inaccuracy of the cam shaft movement, and also up and down with respect to the plate, this construction at the same time permitting quick and easy removal of the plate to which the ignition parts are attached.

'7. A circuit breaker construction, in accordance with claim 5, in which there is a slot and bracket floating type of connection between the plate and the casing which transfer the pressure between the cam shaft and the surfaces whose purpose is to force the cam shaft to run true to the cam or cam shaft which thereby causes less wearing of the surfaces holding the cam shaft in its true position, thereby greatly increasing the length of time an ignition breaker will function properly.

8. A structure, in accordance with claim 5, in which the point assembly plate has a readily detachable and floating type of connection, comprising a slot and projection assembly between the edge of the plate and the inside of the casing whereby the plate and the circuit breaker assembly may be bodily removed and replaced to easily and quickly change a damaged point assembly without highly trained technical labor and with a minimum loss of time in which the circuit breaker is out of service.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,886,566 Mallory Nov. 8, 1932 FOREIGN PATENTS Number Country Date 211,174 Switzerland Nov. 18, 1940

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