US1418175A

US1418175A - Timing mechanism

Info

Publication number: US1418175A
Application number: US430015A
Authority: US
Inventors: Wolfgang E Schwarzmann
Original assignee: American Bosch Magneto Corp
Current assignee: Ambac International Corp
Priority date: 1920-12-11
Filing date: 1920-12-11
Publication date: 1922-05-30
Anticipated expiration: 1939-05-30

Description

UNITED STATES PATENT OFFICE.

WOLFGANG E. SCHWARZMANN, 0E LONGMEADOW, MASSACHUSETTS, ASSIGNOR TO,

AMERICAN BOSCH MAGNETOCORPORATION, OF NE JV YORK, N. Y., A CORPORATION or New YORK.

TIMING MECHANISM.

Specification of Letters Patent. Patent d pl 30 1922 Application filed December 11, 1920. Serial No. 430,015.

T 0- all whom it may] concern:

Be it known that I, WOLFGANG E. SonwAnzMANN, a citizen of the United States, residing at Longmeadow, in the county of Hampden, State of Massacl'iusetts, have invented certain new and useful Improvements infTiming Mechanism; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to adjustable timing devices for magnetos, and particularly one adapted to be carried by the interrupter housing of the magneto.

An ignition system almost invariably provides variable timing; periods to suit different speed and load conditions imposed upon the engine with which it is assocated. To that end, the mechanical interrupter-of the magneto or sparking coil has an adjustable member towhich is attached .a timing member connected by an adjusting rod or wire to the control lever on the steering wheel or post of an automotive vehicle or a convenient part of a stationary organization. Heretofore, it has been customary to fasten a timing arm to the adjustable member of the illterrupter by a screw or other securing means for rigidly connecting them together, but in such arrangement the adjusting pull on the control. lever is applied at a single point of the periphery of theadjustable member'and sometimes causes the adjustable memberto bindfin its bearing, particularly if a decided increase in the rcsistai'icedevelops in the bearing.

her to be located on one side or the other of the adjustable member of the interrupter, or

above or below it, or at some intermediate point, in order that the control lever may be attached to it most con eniently, The adjustable member ordinarily in the form. of a ring carrying cams which areperiodically engaged by the dcflectable element of a pair of contact carrying elements. These cams are accurately positioned and fastened in the adjustable member, or cam' ring,by the manufacturer of theinterrupter, and therefore, the engine builder is frequently inconvenienced in installing the magneto or the adjusting rod or wire. To meet this difli culty, the adjustable member or cam ring of the interrupter has been provided with slots into a selected one of which is set a lug carried by the timing ring surrounding the cam ring, and to the timing ring is attached a timing arm connected to the rod or wire, as above stated. While this arrangement provides for several positions of connection, it does not, however, provide for universal relative angular adjustabillty of r i the timing ring and cam ring, and it also requires a thicker adjustable member to provide for the slots. This results as before, in a single point of application of the adjusting pull to the adjustable member. Furthermore, the timing ring is not'positively prevented from working off iromthe adjustable member inan axial direction as a result of the continual vibration to whichit is subjected by the engine.

The timing ring is usually rigid or into-- gral with the timing arm, both having a common radial slit to permit a certain amount of flexing of the ring halves and the arm portions on each side of the slit in the arm. A clampingscrew is used to flex the parts so as to clamp the ring halves upon the periphery of the cam ring. The pres sure thus applied by the timing ring upon the cam ring forces the lattelf' out of the true circular shape and a uniform result can never be produced due to theeccentricity of the rings upon the contraction of the split timing ring; Furthermore, such timing ring can grip the cam ring at only two points, or but a few points, around its circumference instead of substantially the whole circumference or periphery thereof. Such structure cannot meet the requirements I I i of providing a connection adaptedfor all It is often necessary for tlie'tinnngi 1nem'' desired/angular relations between the timing arm and the adjustable interrupter element nor the precise cooperation necessar ily required in a magnetobetween the stationary and rotatable elements of theinterruptera Vith the above in view and with the object of producing a simpler, cheaper and more e'tlicient device, I have in accordance with one part of my invention, devised an adjustable timing device comprising an annular band parted or split along a radius thereof and having radially extending portions at said parting between which is placed an end of a timing arm and to whichsuch end of the arm is attached by suitable securing" means, the latter acting to ti hten the band about the cam ring on the inter rupter housing in any relative angular position, the forces, acting to cause the band to tighten, being equally applied to the ra dially, extending portions substantially along a plane tangential to the periphery of the cam ring at the point or line of parting so that the binding stress will be imposed upon the band along its circumference with a resultant uniform distribution of pressure along the contacting surfaces of the band and cam ring, and with a tendency to shorten the circumferential length of the band so as to cause the inner end of the timing arm to be forced radially inwardly against the periphery of the cam ring to more effectively, positively maintain the timing arm and cam ring in adjusted relation.

In accordance with another part of the invention the radially extending portions of the band have reinforcing return-bent portions which give increased thickness and rigidity to the radially extending portions.

As another part of the invention, whether or not the radially extending portions have, although preferably having, reinforcing portions, the timing arm has one or more tongues located between the radially extend in portions of the band and secured to such portions by suitable securing means. the latter serving as a common means for d rawing the radially extending portions toward each. other for a uniform tighteningot the band about the cam ring, as well as for securing such portions to the end, tongue or tongues of the timing arm and. for radially drawing the inner end of the tongue or tongues into iirmer engagement with the outer surface of the cam ring.

As another part of the invention, whether or not the radially extending portions have, although preferably having, reintorcing portions, the timing arm is slitted to provide flexible tongues to which the radially extend .ing portions of the band are secured so that as the tongues are tlexed by the securing means the radially ending portions of the hand are caused to mutually approach under balanced stresses acting in planes substazr tially tangential to the periphery of the cam ring so as to produce a uniform tightening of the band about the cam ring and an inward draw in a radial direction of the inner end of the tongue against the periphery ot the ram ring.

in the acci'nnpanying drawing illustratingpreferred and modified embodiments of the invention:

Fig. 1 is an end view in elevation of one form of device, constructed in accordance with myinvention, in connection with. a cam ring of a mechanical interrupter" Fig. 9- is a side view of the same: 7 plan view of the same; Fig. l is verse section of the same; F i

side view of the band; Fig. 6 is a view of a modified form of the band and timing arm in end elevation; Fig. 7 a top plan view thereof; and Fig. 8 is a sectional view.

Referring more particularly to the draw ing the adjustable timing device illustrated in F 1 to 5 inclusive, comprises a timingarm 1 having an aperture 2, in which may be connected the timing rod or wire leading to the steering wheel or other convenient accessible part of the vehicle, and having an end portion 3 preferably in the form of a tongue. The binding or clamping ring l is of annular form and is'cut, split or parted along a radius thereof so that the band may expand or contract. The band preferably has integral radially extending portions 5, at the point of parting, between which is located the tongue 3 of the timing arm, a securing means, such as a screw bolt 6, passing through suitable apertures provided in both of the radially extending portions 5, and the tongue 3 for rigidly securing said portions and tongue together, as is clearly shown in Fig. 1. Ea ch radially extendingportion preferably provided with a return-bent portion T folded back upon the portions 5 so as to form therewitha thickened and more rigid extension.

It will be apparent that the tongue is relatively thin so that the portions 5 may be located as practically near to each. other as possible whereby as the binding screw or bolt causes the members 5 to niuitual 2117])1'O2L0ll, the forces acting upon the band 4: to contact its size will not substantially in a plane tangential to the periphery of the cam ring 8 at the point or line of parting of the band 4-. It will further be noted that the securing bolt or screw serves both. purposes of tightenin the band upon the cam ring, by causing a relative approach of the portions 5, and securing the latter rigidly to the tongue 3 of the timing arm. It will be further noted that the band lis relatively thin so as to have substantial flexibility for the purpose hereinafter more fully shown.

Referring to the embodiment illustrated in Figs. (3, 7 and S, the adjusting device coinprises a timing arn'i 9 having an aperture .O, for the reception of an end of a timing rod or wire leading to a convenient accessible part of the vehicle, and a slit ll. cut into one end of the arm so as to provide tongues 12 on each side of the slit, the tongues being capable of flexing under suitable stress, The l'GlZLtlVOl) thin and flexible band 13 preferably has integral radially extending portions 14; disposed in spaced parallel. relation and secured upon the outer surfaces of the tongues 12 by a suitable securing means, such as a binding screw or bolt 15 passing through and operative in suitable apertures provided in the portions 14: and tongues 12.

As the securing screw is operated the tongues 12 are flexed to mutually approach.

It will be noted that in both forms of dc vice shown the application of forces or stresses is divided equally bet-ween the radially extending portions since the stresses are applied simultaneously and inopposite di rections so that the binding or tightening effect of the band will be equally or uniformly distributed throughout the surfaces of contact between the band and the cam ring. The forces or stresses are applied close to the periphery of the cam ring so that as the ends of the band are drawn together these forces will not substantially along a plane tangential to the cam ring at the point or line of separation between the ends or radially extending portions of the band, so that the resultant forcesacting through the band will be substantially along the circumference of the band. As the band is contracted there is a tendency to shorten its circumferential length and hence is circular size whereupon the inner ends of the tongue 3 or tongues 12 are drawn inwardly radially against the surface of the cam, ring for firm engagement therewith, such engagement becoming greater upon the greater tendency to contract the band. In use, the band in expanded condition is placed over the cam ring and the tongue or tongues of the timing arm inserted between the radially extending portions of the band after which the securing means or screw is inserted in place. Just before tightening the securing means the timing arm and the band is rotated to any desired angular position with respect to the cam ring before contracting the band upon the cam ring, thus providing a universal adjustment of the device relative to the cam, ring, and hence, the interrupter elements. The screw is then tightened to contract the band about the cam ring and to cause the radially extending portions to bind with the tongue or tongues of the timing arm and to firmly engage the periphery of the cam ring, the securing means serving as a common means for both functions of contracting the band and of securing the timing arm to the radially extending portions of the band. Inasmuch as the band is relatively thin it will not offer resistance to flexing action so as to merely cause the band to contact at but a few points upon the periphery of the cam ring, but will have a tendency to deliver the forces along the band so that pressure is applied uniformly and evenly throughout the surfaces of contact between the band and my invention what prising an interrupter housing having a cam ring the combination of an annular band parted along a radius thereof and having radially extending portions at the parting thereof,a timing arm having an end there of between said portions and means for securing said portions to said end of said arm and for tightening said band about said ring.

2; In a timing device for magnetos comprising an interrupter housing having a cam ring, the combination of an annular band parted along a radius thereof and having radially extending portions at the parting thereof, a timing arm having an end thereof between said portions, saidportions having reinforcing return-bent portions, and means for securing said reinforced portions to said end of said arm and for tightening said band about said ring.

3. In a timing device for magnetos eomprising an interrupter housing having a cam ring, the combination of an annular band parted along a radius thereof and havingradially extending portions at the parting thereof, a timing arm having a tongue between said portions and means for securing said portions to said tongue and for tightening said band about said ring.

i. In a timing device for magnetos comprising an interrupter housing having a cam ring, the combination of an'annular band parted along a radius thereof and having radially extending portions at the parting thereof, a timing arm having a tongue located between said portions, said portions having reinforcing return-bent portions, and means for securing said reinforced portions to said tongue and for tightening said band about said ring. v

5. In a timing device for magnetos comprising an interrupter housing having a. cam ring, the combination of an annular bandv parted along a radius thereof and having radially extending return-bent portions at the parting thereof a timing arm having a tongue between said portions, and common means for moving said portions toward each other for tightening said band about said ring and for securing said portions to said tongue and in tightened position.

6. In a timing device for magnetos comprising an interrupter housing having a cam ring, the combination of an annular band parted along a radius thereof and having radially extending portions adjacentthe parting thereof, a slitted. timing arm having flexible tongues adjacent the slit thereof and located between said portions and means for securing said ends to said tongues and for fiexinv said tongues for tightening said band about said ring.

' In testimony whereof I aflix my signature.

WOLFGANG E. SC HWARZMANN.