US1021506A - Circuit-breaker for magnetos and the like. - Google Patents

Description

R. H. CUNNINGHAM.

CIRCUIT BREAKER FOR MAGNETOS AND THE LIKE.

APPLICATION FILED FEB. s, 1911.

1,021,506. v Patented Mar. 26, 1912.

witwwoeo 4 (1 W00 14 foz 3513 Gr mm 12135 W' Application filed February 8, 1911.

UNITED STATES: PATENT orrrcn.

'RICHA -BD n. CUNNINGHAM, on NEW r onx, N. Y.

CIRCUIT- IB REAKER FOR MA GNETOS AND THE LIKE.

To all whom it may concern:

Be it known that I, Ric-HARD Hoorn CUN- NINGHAM, a citizen of the United States, residing at- New York city, in the borough of Manhattan and State of New York, have invented certain new and useful Improveobject the provision of a novel circuit breaking mechanism which is adapted to make and interrupt the circuit through the primary of the magneto at proper and regular intervals, no matter what the speed of. the engine, or of the armature of the magneto,

' may be.

In devices of this character as heretofore constructed, it has been customary to depend solely upona spring or springs as the brate.

means of maintaining two contact points or elements normally in opposition; co-acting devices being provided which are intended to break contact between said points at given intervals when the'armature shaft, upon which the device is usually mounted, is rotated. The difliculty encountered herem in, however, is that the parts involved necessarily have some weight and hence some inertia. Furthermore each spring has a definite periodicity at which it tends to vi- Hence, when the said shaft is rotating at very high speed, the spring, even if made quite strong, in order that it may urge the points into contact after they have been separated by the impingenient'of a moving part against a fixed part or parts,

is still unreliable owing to its periodicity,

an'dthe use of a powerful spring is further obviously objectionable for many reasons, such for example, as increased friction and Wear and tear on the device.

I have devised means whereby the action of centrifugal force may be employed to effect the desired contact between the points in question, and prefer to. supplement this action by that of a verylight spring sothatthe contact points or,v elements will be normally maintained in contacting relationship "at all times except when'they are forcefully Specification of Letters Batent.

Patented-Mar. 26,1912.

Serial No. 607,269.

driven apart by devices provided for that purpose. Furthermore, while when the shaft carried parts are being rotated at a relatively low speed, and hence while the light spring aforesaid will be amply strong enough to effect such closure, the centrifugal action will not be very material, and the wear will be correspondingly diminished; but as the speed of rotation ofthe parts is increased, this centrifugal action becomes more and more pronounced, so that in effect I have provided a variable pressure contactclosing mechanism; These and other objects of my invention will be hereinafter referred to and more particularly pointed out in the appended claims.

In the drawings which form a parthereof, and in which like reference characters designate'likc parts throughout the several views: Figure 1 is an elevation of a preferred form of my invention. Fig. 2 is a horizontal section of the same taken on the line 11-11 of Fig. 1. Fig. 3 is a fragmentary vertical transverse section of the same taken on the line lII -III of 1.,

Referring to the drawings, a cylindrical frame or ring 1 is mounted upon a suit-able casing 2 which is adapted to be secured to -the magneto frame in any suitable manner,

said cylindrical frame having .an extension 3 whereby the same may be oscillated in the usual manner. One extremity of the armature 4 which is centrally disposed with respect to the said casing and ring preferably carries an armature trunnion 6 which may be mounted upon suitable ball bearings 7, in the manner shown in Fig. 2. In so far as the present invention is concerned, how'- ever, the manner of supporting the armature is immaterial, so that the same willbe but briefly referred to. The trunnion forming element 6 is recessed interiorly for the reception of a circuit breaker support 8, the hub 9 of which fits neatly into the element 6 and is hence carried and rot-ated thereby; being secured thereto in any suitable manner. The body of .thissupportispreferably a'circular disk, and upon this disk are mounted the rotative' elements ofthe circuit breaking mechanism'towhich this invention relates. Substantially central-1y disposed upon thesupporting disk a bracket 11 of bronze or other suitable material which .is

insulated. fromfthe diskfby an insulating washer, v 12,. being secured thereto in; any

suitable manner, as for" exampleb'y'mea'ns of a bolt or screw 13, whichis threaded into usual lock nut 18 and the contact point 17 is adapted for contact with a similar point or element 19 which is carried by an operatingpart or lever 20, upon one extremity of such part. This operating part is preferably a lever of the first-class, andis pivoted at 21 to the support or base 10, being in electrical communication therewith. An important feature of my invention is involved,

in the construction of this lever,'the short 7 arm 22 of which is preferably so positioned .with respect to the long arm 23 of the lever that a right line passing through the center of gravity of arm 22 and the pivotal axis is angularly disposed with respect to a right line passing through the center of gravlty of arm 23 and the said pivotal axis, such short arm being relatively heavier than said long arm, the'latter being preferably quite thin. The contact element 19 is secured to the free endof arm 23. .At the outer extremity of arm 22 is mounted a normally .non-revoluble cylindrical member 24 which is preferably nicked as at 25at intervals around the peripheral surface thereof, said nicks being adapted for the reception of the extremity of a leaf-spring 26. This spring is secured to the lever in any suitable manner as by means of a screw 27, and has its other extremity 28 adapted for engagement witlra in 29, which projects laterally from the 'sur ace of the base 10. I prefer to notch the'pin 29 as at 30 for the reception of this spring to prevent lateral displacement of the latter; An axially disposed stud orbolt 31 extends through bracket 11, insulati'n Washer'12 and an insulating sleeve 32 whic ispositionedwithin the cap 9; this belt being threaded into the hub of a; disk 33 so that when. screwed firmlyinto position it tends to draw all of the parts in question firmly .together. Bolt 31 further serves as means for conducting current -from the bracket 11 to the disk'33 and this disk is electrically connected in any suitable manner, as by means of aset screw 34, with a; lead 35 which preferably extends the usual fashion to the primary coil of the magneto. The periphery of the disk 33'may be insulatedly spaced from the wall of the recess in the element 6 by a r' 36 of insulating material, while the outer surface of the said disk is correspondingly insulated from the trunnion forming element 6 by means of an-insulating washer. 37. .It will hence be I seen that current maybe led' into disk 33 from lead 35 and will thence traverse stud 31, bracket 11, screw 16, and the contact elements or .points 17 and 19, provided the erable to have a sliding engagement betweenthese parts rather than a rolling contact and have for this reason notched the said roller and adapted it to be held'by the spring 26 inthemanner above described; As the cam engaging portion of the roller becomes worn,

the roller may be shifted around to afford a new engaging surface. 7

The operation of the device is as follows: When the revoluble part of the magneto, to wit, the armature is rotated, current will be generated in the usual manner inthe mag-- neto primary coil. Rotation of the armature'will correspondingly rotate the support 1 10 and thereby cause a surface of the member 24 to successively impinge against cams 38. This action will periodically forcibly separate the contact points 17 and 19 and thereby periodically ,lnterrupt the flow of current through the primary. Spring 26 is preferably \a very light one so that it normally tendsto press contacts 17 and 19 lightly together. By reason, however, of the dispositionof' the arm 22 and by reason, further of the fact that this arm and relatively heavier parts, 2'. e., the member 24 and its stud, carried thereby, will tend under the influence of centrifugal force to swing outwardly about the pivotal axis of the lever and will thereby normally forcethe contact points more firmly into engagement with each other.' When the member 24 encounters a cam 38 the contact elements-will be separated in spite of this combined action of the spring and centrifugal force; but the arrangement in question is a particularly efficacious one in View of the fact that as the speed of rotation is increased the tendency-of the contact carrying lever or operating part to move into circuit closin Y position is increased. To the best of my edge, heretofore, in devices 'of this character springs have been relied upon solely for the urpose'oi efiectingrthe closure of circuit,

I ut this fconstruction is open to several objections and subject to disadvantages, in

that whilethe spring is able to effect contact fair-1y uniformly so long as the speed points of rotation is not greafi this closing action is seriously interfered withwhe'n the speed of rotation of the parts is veryfln'gh, and since under such conditions the spring, 1111- less a very heavy one be employed, is not powerful enough normally to close the contacts when the same have been forced apart by the impingementof a roller or the like the said upon one of the operating cams,

roller encountering a second cam before the lever has had time to move to circuit closin position; or at least before the contact have been well pressed together to afford a proper closureqof circuit. When in order to obviate this difficulty the spring or springs have been'made strong, the friction and wear and tear upon the mechanism have been, of course, materially increased. Furthermore, since every spring has a cer-' p tain periodicity of vibration, when the parts are rotating at great speed, thischaracteristic of the spring will in turn tend to interfere with the pro er closure of the circuit. Obviously, also, 0 osure solely by spring action is not positive; and by devising a mechanism of the character in question in which the action of centrifugal force. is

I claim is:

1. In a circuitbreaker, a supportrotatable about an axis and adapted to be carried upon the extremity of a shaft, a bracket carried by said support, a contact elementadjustably mounted in said bracket, a lever of the first class pivotally connected to said support, said lever having one arm thereof heavier than the other, a part adapted. to contact with the fixed element carried by the lighter arm of said lever beingadapted to be rotated about its pivoted axis by centrifugalfo'rce when the sup ort is rotated, and said contact elements eing thereby. normally held in contact, and means for separating said elementsat determined intervals durinlgnthe rotation of said support.

. 2. a. circuit breaker, a 'su port rotatable about an axis and adapte to be carried upon the extremity of a shaft, a bracket carried by said support, a contact element adjustably mounted in said bracket, iii-lever ofthe first class pivotally con'n'ected to said support, said lever having one arm thereof weighted heavier than the otherfia part adapted to cont'a aforesaid, said li hter arm of the lever, said lever being adapted to be rotated about its pivotal axis ct, with thecontact element by centrifugal force when the supportiS rotated and saidcontact elements being thereby normally held in contact, means for separating said elements at determined intervals part being carried by the 1 during the rotation of said support, and" rom said means for insulating said lever bracket.

3. In an electric circuit controlling device,

a rotatable support, a lever of the first class ivoted thereupon, contacting means operable by said lever, one of the' arms of said lever being weighted heavier than the other,

said lever being rotatable-about its pivotal axis into its circuit closing position bythe action of centrifugal force when said support is rotated, a spring attached-to said lever and normally urging said lever into the said. circuit closing position, the 'action of said spring bein centrifugal action a oresaid, and means for forcing said lever into open circuit position.

4. In an electric circuit controlling device, a rotatable support, a lever of the first class pivoted thereupon, contacting n'ieans ope r' able by said lever, one of the arms of said lever being weighted heavier than the other,- .'said lever being rotatable about its pivotal axis intoits circuit closing position by the action of centrifugalforce when said sulpport is rotated, a spring attached to said ver normally urging said lever into the said circuit closing position, the action of said spring being supplemented by the centrifsupplemented by the ugalaction'aforesaid, and-means for forcing said lever into open-circuit osition, said means comprising a springeld notched roller carried by said lever and a cam relatively fixed with respect to said support. In witness whereof, I subscribe my signature, inhe presence of two witnesses.

LRICHARD H. CUNNINGHAM. Witnesses 'Wamo M. Ciamrm, WrLLm u C. LANG.

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