US3076875A

US3076875A - Electrical apparatus

Info

Publication number: US3076875A
Application number: US89015A
Authority: US
Inventors: Richard B Clark
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1961-02-13
Filing date: 1961-02-13
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05
Also published as: GB937895A; ES274560A1

Description

Feb. 5, 1963 R. B. CLARK 3,076,875

ELECTRICAL APPARATUS Filed Feb. l5, 1961 IN V EN TOR. RICHARD B. CLARK lam/Mp3?! ATTO NEYS the housing of the United States Patent 3,976,375 ELECTRHCAL APPARATUS Richard l3. Clark, Eidney, My, assignor to The Bendix Corporation, Sidney, NY a corporation of Delaware Filed Fete. 13, 1961, Ser. No. 89,015 it) Claims. ((35. Nth-30) This invention relates to novel electrical apparatus, and more particularly relates to a novel ignition breaker assembly for a spark ignited internal combustion engine.

The invention has among its objects the provision of a novel ignition breaker assembly which is particularly characterized by its simplicity of construction.

A further object of the invention lies in the provision of an ignition breaker assembly which may readily be accurately adjusted by the use of simple tools such as screw drivers.

Yet another object of the invention lies in the provision of an ignition breaker assembly of such construction that it may be disassembled if necessary and one or more parts thereof, such as the breaker points, may easily be replaced.

The above and further objects and novel features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only, and are not intended as a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a fragmentary view in plan of a portion or" an internal combustion engine provided with an ignition breaker assembly in accordance with a first embodiment of the invention, the shaft of the engine bearing the cam for operatim the breaker being sectioned horizontally;

FIG. 2 is a view in side elevation of the breaker assembly of FIG. 1, the view being taken in the direction from right to left in FIG. 1, a portion of the engine upon which the breaker assembly is mounted being shown in section;

FIG. 3 is a view in section through the breaker assembly of MG. 1, the section being taken along the line 3--3 of FIG. 1; and

PEG. 4 is a fragmentary view in plan of an alternative embodiment of breaker assembly in accordance with the invention.

The improved breaker assembly of the invention is illustrated in connection with its use with an engine such as a two-cylinder, two-cycle engine of which a marine outboard engine is typical. it is to be understood that the ignition breaker assembly of the invention is not limited to such use, since it is obviously capable of use to advantage for making and breaking circuits in devices other than engines and when used in an ignition system may be employed with engines other than the type illustrated.

Te breaker assembly of the invention is an improvement upon prior breaker assemblies wherein a breaker lever is permanently atlixed to a contact-supporting bracket by a pivot pin. In such prior constructions an extension of the pivot pin serves rotatably to locate the bracket on a fixed part of the engine housing, and to permit adjustment of the bracket to permit a cam follower on the breaker lever to be adjusted toward or away from the axis of the cam which operates the breaker lever. in the described prior construction the bracket is held in the desired angular position by a screw threaded into engine and extending through an arcuate slot in an outer edge portion of the bracket.

in such prior breaker assemblies the pivot pin mounting the breaker lever is headed and is permanently aifixed to the bracket. The construction is such as not to allow the ordinary engine owner to disassemble the breaker assembly and to replace parts such as the breaker points thereon. Consequently, when one part of the assembly requires replacement, the complete breaker assembly must be replaced. Further, it is difiicult accurately to adjust the prior breaker assemblies in the manner described and to maintain the assembly in its desired adjusted position while the retaining screw therefor is being tightened.

In the breaker assembly in accordance with the present invention, the breaker lever is pivotally mounted upon a pivot pin, such pivot pin also serving as the means for retaining the bracket in adjusted position upon the fixed housing or supporting element. As a result, the construction of the breaker assembly is markedly simplified. The breaker assembly is provided with means whereby the bracket thereof may be accurately adjusted after the pivot pin has been loosened, and whereby the bracket may be forcibly held in the desired adjusted position upon the tightening of the pivot pin. in preferred embodiments of the breaker assembly, the breaker lever may be readily removed from the bracket so as to permit free access to the breaker points so that they may be more readily dressed or ground when required. in the illustrated alternative embodiment, the construction is such as to allow the contact points readily to be replaced after the breaker lever has been removed from the bracket.

The first embodiment of breaker point assembly in accordance with the invention, which is shown in FIGS. l, 2, and 3, is generally designated by the reference character 16. The assembly Ill is shown mounted upon a fixed housing portion 11 of an engine. A two-lobed cam .12 is shown fixed to a shaft 14, the assembly 19 and cam 12 being so located relative to each other that the breaker points of the assembly 10 are opened upon the passage of each lobe of the cam past the cam follower of the assembly. The construction shown is typical of a two-cylinder, two-cycle engine wherein the shaft 14 is the main shaft of the engine. Such engine is provided with a second breaker assembly, not shown, dis posed diametrically opposite assembly it) with respect to shaft i4. Each such assembly is operatively connected to energize the spark plug of the respective cylinder of the engine.

The assembly Tail includes a contact-mounting bracket 16 which may be made of a metal plate cut and bent to the appropriate shape. Bracket 16 has a fiat main body 17 which is adapted to lie upon the fiat upper or outer face of part 11 of the engine. The lower end portion of body 17 as it is shown in the drawings is provided on the right-hand edge thereof with an upstanding finger 19 upon which a fixed contact 2%) is mounted. In the first embodiment of the breaker assembly both the fixed contact 2;? and the movable contact 21, to be described, are permanently secured to their respective supports as by being riveted thereto. The movable contact 21, which is disposed generally in alignment with contact 29, is mounted adjacent the outer end of a first arm 24 of a breaker lever 22 made of electrically insulating material. Lever 2A is a first-class lever of generally l...-shape.

Lever 22 is pivotally mounted at substantially its midpoint upon a pivot pin or stud 25 which has its lower or inner end 26 threaded and threadedly engaged in a passage 27 in element ll. As s hown in FIG. 3, pivot pin 25 has a short circular cylindrical portion 29 thereon outwardly of or above its threaded portion 26. Portion 29 of the pivot pin extends through a hole 3! in portion 17 of bracket 16 so that the bracket may turn around portion 29 of the pivot pin as a bearing. Portion 29 is somewhat shorter in an axial direction than the thickaoraere ness of body 17 of the bracket. Outwardly of portion 29 the pivot pin is provided with a collar 31 which is fixedly secured thereto as by being made integral therewith. Collar 31 overlies the portion of body 17 of the bracket which surrounds hole 30 therethrough. It will be seen that when the breaker assembly is mounted on element 11 in the manner shown, a tightening of pivot pin 22 will cause body 17 of the bracket to be drawn tightly into engagement with the outer or upper surface of element'll. Contact between the body of the bracket and the element 11 is particularly concentrated in the region of the collar 31; such concentration of the holding force allows the bracket to be securely held in adjusted position upon the application of a no more than normal tightening torque to the pivot pin 25. The pivot pin 25 may conveniently be turned to tighten or loosen it as described by means of a screw driver engaged in a slot 35 in the outer end of the pin.

Outwardly beyond collar 31 the pivot pin 25 is provided with a circular cylindrical bearing portion 32 of appreciable length. Portion 32 of the pivot Pin is aceurately received within a journal bushing 34 which may be in the nature of an insert molded into the breaker lever 22.

The other arm of breaker lever 22 is generally designated 36. Such arm bears an inwardly facing short finger 37 which acts as a cam follower riding upon the outer surface of cam 12. The breaker lever may be provided with a felt 39 which surrounds the base of cam follower 3'7 and extends along the inner face of lever 22 wherein the felt is held by opposite bent arms 40 which are integral with a sheet metal felt holder 38 fixedly mounted on the lever.

At the other end of bracket 16, shown at the top in the drawings, the bracket is provided with a second upstanding finger 41, the main extent of which lies in a plane generally at right angles to the plane of finger 19. Finger 41 serves as a support for an insulated terminal generally designated 42 by means of which the movable contact 21 is electrically connected to the ignition cir- .cuit. The terminal 42 is an L-shaped metal member having a first arm 44 which lies inwardly of and parallel to the finger 41. Terminal 42 is secured to finger 41 by means of a screw 45 which extends in that order through an insulating washer 46, through a hole in finger 41, through an insulating washer 47, and through an end 52 of a leaf spring, to be described. The shank of screw 45 is electrically insulated from finger 41 by means of an insulating sleeve (not shown) disposed in the hole through finger 41 and surrounding the shank of the screw. Terminal 42 has an outer arm 49 to which a lead wire (not shown) from the ignition circuit may be attached.

The breaker lever 22 is constantly resiliently urged toward contact closed position, that is, counterclockwise in FIG. 1 by one or more leaf springs secured to the outer end of arm 24 and to finger 41. In the embodiment shown, two such springs are employed, an outer full length spring 50, which also serves as a current lead from terminal 42 to contact 21, and a short inner cantilever spring 51 which serves to reinforce spring 50. The ends of springs 50 and 51, shown at 52, are secured to linger 41 as above explained. The outer end of spring 50 is straight and lies along a face of arm 24 of the breaker lever. The shank of movable contact 21 extends through a hole in portion 54 of spring 50 and thus serves to attach such end of the spring to arm 24.

' Body 17 of the bracket is provided at a location outwardly of breaker lever 22 with a slot 55 .providedbetween two projecting ear portions 56. Supporting element 11 is provided with. two upstanding spaced generally parallel abutments 57 which provide a slot between them which is generally in alignment with-slot 55. The described slots, ears, and abutments provide gte aswtet br he b acket may be turned about pivot pin 25 a required small amount when the pivot pin is loosened, and may be held in a desired adjusted position until the pivot pin has been tightened. Such adjustment may readily be made by an operator with a screw driver in each hand. With one screw driver he loosens pivot ,pin 25 sufficiently to allow bracket 16 to be turned. He inserts the other screw driver 59 (FIG. 1) into the slot formed between cars 56 and abutments 57 and turns such screw driver to swing the bracket to the desired adjusted position. The second screw driver may be left in place or turned so as to oppose the tightening action of pivot pin 25 as the latter is being tightened.

In FIG. 4 there is shown a portion of a modified breaker assembly in accordance with the invention. The assembly of FIG. 4 is the same in all respects as that shown in FIGS. 1, 2, and 3 with the exception that the fixed and

movable contacts

20 and 21 thereof are removable from the finger 19 and the arm 24, respectively. Thus the contact 20 has a threaded shank 60 which extends through a hole in finger 19. Such contact is retained on the finger by a spring lock washer 6'1 and a nut 62. Contact 21' is similarly mounted on arm 24. A threaded shank 64 of such latter contact extends through a hole in arm 24. Contact 21 is retained in place by a spring washer 65 and a nut 66.

With the described construction of the breaker assembly of the invention, either of contacts 26) and 21 may be readily removed and replaced as required without the use of special tools. To allow such replacement of one or more contacts, the connection at terminal 42 is disassembled so as to allow the one or more leaf springs connected thereto to be removed. Such disconnection of the leaf spring allows the breaker lever 22 to be freely withdrawn axially from the unheaded pivot pin 25. When the breaker lever has been thus removed, either of contacts 20' and 21 may be removed by removing the nut and spring washer from its shank, followed by withdrawing the contact axially from its sup port. A new contact can readily be installed by a reverse procedure. The breaker lever is then again mounted on pivot pin 25 and the terminal 42 is reassembled so as to restore the parts, including the leaf spring or springs, to the positions shown in FIGS. 1, 2 and 3.

Although only a limited number of embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing specification, it is to be especially understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art. Thus, if desired, the lever 22 may be additionally held upon stud 25 by the provision of a snap or spring ring inserted in an annular groove adjacent the outer end of the stud so as closely to overlie the lever and to retain the lever against undue movement axially of the stud. The snap or spring ring, which may be a conventional internal tooth type, a ring made from round wire, or a hair-pin type retainer, may readily be applied and removed when desired.

What is claimed is:

1. In a spark ignition engine having a shaft driven in synchronism with the engine, a cam mounted on the shaft for rotation therewith, a fixed support having a flat surface disposed near and normal to the axis of the shaft, and a set of breaker points cooperating with the cam so that the points open and close in synchronism with the engine, the improved breaker point assembly which comprises a contact support-in the form of a bracket having a flat plate-like body lying upon the flat surface of the fixed support, an upstanding pivot pin extending througha hole in the body of the bracket generally centrallythroughsaid area of-contact with thesuppor-t'and synchronism with the engine, a cam for rotation therewith, a fixed support having a surface disposed near and having at least trial to the axis of the shaft, and

having a threaded inner end screwed into a threaded passage in the fixed support extending normal to the flat surface of the support, a collar fixedly secured to the pivot pin and overlying the body of the bracket so as to thrust the body forcibly against the fiat surface of the support and to retain it from turning about the pivot pin when the latter is tightened, the pivot pin having an outer portion extending a substantial distance outwardly of the collar, a breaker lever pivotally-mounted on the outer portion of the pivot pin, the breaker lever having a first, movable contact mounted thereon, the bracket having a second, fixed contact mounted thereon so as to confront the first contact, the breaker lever cooperating with the cam so as to be moved thereby so that the contacts periodically engage each other and are then moved apart. 2. In a spark ignition engine having ashaft driven in mounted on the shaft its general plane nora set of breaker points cooperating with the cam so that the points open and close in synchronism with the engine, the improved 'breaker point assembly which comprises a contact support in the form of a bracket having a plate-like body lying upon the said surface of the fixed support and having extended contact therewith, an upstanding pivot pin extending through a hole in the body of the bracket through said area of contact with the support and having a threaded inner end screwed into a threaded passage in the fixed support, a collar fixedly secured to the pivot pin and overlying the body of the bracket so as to thrust the body forcibly against said surface of the support and to retain it from turning about the pivot screw when the latter is tightened, the pivot pin having an outer portion extending a substantial distance outwardly of the collar, a breaker lever pivotally mounted on the outer portion of the pivot pin, the breaker lever having a first, movable contact mounted thereon, the bracket having a second, fixed contact mounted thereon so as to confront the first contact, the breaker lever cooperating with the cam so as to be moved thereby so that the contacts periodically engage each other and are then moved apart.

3. In a spark ignition engine having a shaft driven in synchronism with the engine, a cam mounted on the shaft for rotation therewith, a fixed support having a surface disposed near and having at least its general plane normal to the axis of the shaft, and a set of breaker points cooperating with the cam so that the points open and close in synchronism with the engine, the improved breaker point assembly which comprises a contact support in the form of a bracket having a body lying upon the said surface of the fixed support and having extended contact therewith, an upstanding pivot pin extending through a hole in the body of the bracket and having a threaded inner end screwed into a threaded passage in the fixed support, a collar fixedly secured to the pivot pin and overlying the body of the bracket so as to thrust the body forcibly against said surface of the support and to re- 4. Electrical apparatus as defined in claim 3, wherein 7 the outer end portion of the pivot pin is headless whereby the breaker lever may be withdrawn axially outwardly from the pivot pin, and comprising means for retaining the breaker lever against unwanted axial withdrawal from the pivot pin.

5. Electrical apparatus as defined in claim 4, wherein the means for retaining the breaker lever on the pivot pin is a spring which urges the lever toward contact-engaging position.

6. Electrical apparatus as defined in claim 5, wherein the spring is an elongated leaf spring which overlies and lies generally parallel to the lever with the width of the spring parallel to the axis of the pivot pin, and comprising means to connect a first end of the spring to the bracket and the second end of the spring to the breaker lever.

7. Electrical apparatus as defined in claim 6, wherein the breaker lever is a first-class lever having two generally oppositely extending arms, the pivot pin extends through the lever intermediate the length of the lever, the first contact is mounted adjacent the outer end of a first one of said arms, and comprising a cam follower on the second arm adjacent the outer end thereof, the spring being attached to the first arm adjacent the outer end of said arm.

8. Electrical apparatus as defined in claim 7, wherein the spring is connected at one end to the movable contact, and comprising an insulated terminal on the bracket, the other end of the spring being connected to the terminal, the spring acting as a current lead from the terminal to the movable contact.

9. Electrical apparatus as defined in claim 8, wherein the contact lever is generally L-shaped, the bracket has two upstanding projections thereon to which the fixed contact and the terminal, respectively, are attached, and the contact lever has only a small permissible angle through which it may be turned from engagement of the contacts and abutment of the lever with the terminal.

10. In an apparatus having a driven shaft, a cam mounted on the shaft for rotation therewith, a fixed support having a surface disposed near and having at least its general plane normal to the axis of the shaft, and a set of contacts cooperating with the cam so that the contacts open and close in synchronism with rotation of the shaft, the improved contact assembly which comprises a contact support in the form of a bracket having a body lying upon the said surface of the fixed support and having extended contact therewith, an upstanding pivot pin extending through a hole in the body of the bracket and having a threaded inner end screwed into a threaded passage in the fixed support, a collar fixedly secured to the pivot pin and overlying the body of the bracket so as to thrust the body forcibly against said surface of the support and to retain it from turning about the pivot pin when the latter is tightened, the pivot pin having an outer portion extending a substantial distance outwardly of the collar, a breaker lever pivotally mounted on the outer portion of the pivot pin, the breaker lever having a first, movable contact mounted thereon, the bracket having moved thereby so that the contacts periodically engage each other and are then moved apart.

References Cited in the file of this patent UNITED STATES PATENTS 2,290,078 Thomas July 14, 1942 2,519,976 Phelon Aug. 22, 1950 2,847,524 Slick Aug. 12, 1958

Claims

1. IN A SPARK IGNITION ENGINE HAVING A SHAFT DRIVEN IN SYNCHRONISM WITH THE ENGINE, A CAM MOUNTED ON THE SHAFT FOR ROTATION THEREWITH, A FIXED SUPPORT HAVING A FLAT SURFACE DISPOSED NEAR AND NORMAL TO THE AXIS OF THE SHAFT, AND A SET OF BREAKER POINTS COOPERATING WITH THE CAM SO THAT THE POINTS OPEN AND CLOSE IN SYNCHRONISM WITH THE ENGINE, THE IMPROVED BREAKER POINT ASSEMBLY WHICH COMPRISES A CONTACT SUPPORT IN THE FORM OF A BRACKET HAVING A FLAT PLATE-LIKE BODY LYING UPON THE FLAT SURFACE OF THE FIXED SUPPORT, AN UPSTANDING PIVOT PIN EXTENDING THROUGH A HOLE IN THE BODY OF THE BRACKET GENERALLY CENTRALLY THROUGH SAID AREA OF CONTACT WITH THE SUPPORT AND HAVING A THREADED INNER END SCREWED INTO A THREADED PASSAGE IN THE FIXED SUPPORT EXTENDING NORMAL TO THE FLAT SURFACE OF THE SUPPORT, A COLLAR FIXEDLY SECURED TO THE PIVOT PIN AND OVERLYING THE BODY OF THE BRACKET SO AS TO THRUST THE BODY FORCIBLY AGAINST THE FLAT SURFACE OF THE SUPPORT AND TO RETAIN IT FROM TURNING ABOUT THE PIVOT PIN WHEN THE LATTER IS TIGHTENED, THE PIVOT PIN HAVING AN OUTER PORTION EXTENDING A SUBSTANTIAL DISTANCE OUTWARDLY OF THE COLLAR, A BREAKER LEVER PIVOTALLY MOUNTED ON THE OUTER PORTION OF THE PIVOT PIN, THE BREAKER LEVER HAVING A FIRST, MOVABLE CONTACT MOUNTED THEREON, THE BRACKET HAVING A SECOND, FIXED CONTACT MOUNTED THEREON SO AS TO CONFRONT THE FIRST CONTACT, THE BREAKER LEVER COOPERATING WITH THE CAM SO AS TO BE MOVED THEREBY SO THAT THE CONTACTS PERIODICALLY ENGAGE EACH OTHER AND ARE THEN MOVED APART.