US1478188A - Generation of gear teeth - Google Patents

Description

Deve. 18 1923." 1,478,188

H. E. TAYLOR GENERATION 0F GEAR TEETH originalfiled July 24. 1928 2 sheets-sheet wazig/,TOR I ffl-@M .flTTvoR/VEY atented Dec. l, i223, l

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HERBERT'EDGAR TAYLOR, 0F COVEN'IYRY, ENGLAND.

GENERATION OF GEAR TEETI-I.

Original application filed July 24, 1923, Serial No. $53,453. Divided and thisiapplcation filed October 17, 1923. Serial No.. 668,969.

To @ZZ whom t may 00a-cera: ln carrying out the invention, the arm A,

Be it known that I, HERBERT Encan by means oiz the shaft A2 is pivotally mount- 55 TAYLOR, a subject of the King of England, ed upon a fixed part B, which latter, howresiding` at Covent-ry, in the county of Warever, isv adjustable in relation to the axis ot 5 wick, England, have invented certain new the blank to be acted upon, Lengthwise and usetul Improvements in the Generation upon the arm A are guide members A3 for ol Gear rleeth (for which l have: filed in a slide C on which are mounted the tool 60 Great Britain application No. l99,463, dated holder C2 and tool D of rack form. he

March 22, 1922), of which the following is a direction ot motion of the slide C is lengthspeciication. wise of the arm A, that is, radially of the `This invention relates to the generation pivot axis, and its relative sliding moveof those gear teeth which extend in inv'clute ments are controlled by means ci a cam car'- 65 curves along the'blank and are ot uniform ried bythe xed part B and engaging a stud f normal pitch vfrom end to end as described in or roller C3 or the like, on the slide C.

my application, Ser. No. 653,453, filed July Any suitable type of cam may be adopted 24, 1923, of which this is a division. The obto control the movement of the slide radially ject of he invention isto provide an imand in the construction illustrated it is` con- 70 proved method of generation. stituted by the Aformation of a suitably The invention comprises a method for curved slot E2 in a plate E which is carried generatin 0 O'ear teeth fora'gear system havby the fixed part B' in a plane parallel to v Ab c l u n n ing as its basis a crown wheel whose teeth that 1n which the arm A swings, and is inextend along involutev curves and are ot terehangeable with other equivalent plates uniform normal pitch Jfrom end to end, and arranged to suit the various sizes of gears consists in rolling the gear blank in the path to be cut, and in accordance with the disit would follow if meshed with the said tance of the pivotal axis of the arm A from basic crown wheel, while acting upon it by the axis of the blank upon which the tool means of a tool of rack form which sweeps B acts. The roller C upon the slide C en- 80 out an involute curve Corresponding` to the gages in the cam slot E2 and ensures positive curve of the teeth on said basic crown wheel. reciprocations ot the slide, and preferably, Prefembly the e001 i5 @a1-fied by a Slide although a simple roller C3 is shown, its armovable along an arm which oscillates about rangement would be of a known kindV adapta xed point, during which oscillation the ed to avoid a grinding effect on the cam. @5 slide is acted upon by a cam which varies the t will be seen that the curved slot E2 dit'- acting radius of the tool in such manner ters but slightly from the arc of a circle inasthat, instead of moving in the are of the cirmuch as the axis of the shaft A2 iS located at cle, it traces out the desired involute path. a position such that a curve struck from For cutting double involute gears two of it would conform very closely to the inthese slides are employed, and when approvolute curve which it is desired to produce. priately mounted form a double cutting A slight stop is provided at E3 in the cam 14) head, each slide being actuated by approslot, and the portion seen to the left of this priate mechanism. in the drawing is the acting part which The manner ot carrying out the invention forms the involute curve, while the portion is illustrated in the accompanying drawings, to the right is an extension concentric with in which the axis of the shaft A2 and merely provided Figure l is a front elevation of the tool to allow for the swing of the arm At.

holder, the point of the tool moving in a To operate the slide-carrying arm A, it is plane parallel to the paper. extended upon the side ot a pivot A2 remote Figure 2 is a part-sectional side elevation from the slide C, and for constructional reaof Figure l, sons this extension is separate from the arm Figure 3 is a part plan view as seen from A andV is constituted by another arm A4 fixed above, and to the shaft A2 at some distance from the slide Figure 4 is a view similar to Figure l, C. At the free end A5 of the arm A4 it is but showing an alternative form of cam. connected by means of a link (not shown) to -any appropriate form of driving mech@ anism. Y l e The tool with `its actuating mechanisn is adapted to be used upon a machine in which the blank is arranged to rotate upon its own aXis and also to perform a rolling motion around an axis corresponding to that of the standard crown wheel or equivalent thereofY with which it would be adapted to gear.

The embodiment of the invention as above described is of a simple form and can be constructed in a sturdymanner adapted to reduce wear and to avoid slackness, and is suitable for CuttingY single or double involute gears i. e., those in which the teeth incline one way only, or two ways forming chevrons) but it is to be understood -that the manner of operating the slide andthe arrangement Vof the mechanism therefor is not limited to the construction above described.

Thus, for example, as shown 1n Figure t, the cam may be constituted by an annular disc F coaxial with the point of oscillaticn of the arm A, and the acting part of its outer periphery may be shapedv in the manner above described for the curved slot E2. Rollers Gr, G2 upon the slide C would engage opposite sides of the cani F to cause the movement of the slide, and one'of these rollers G2 would be pressed by the spring G3 against the cani to Vfollow up the movements of the slide and prevent 'any ,shake in it. y Y

XVhere double involute teeth are to be cut, two oscillatingtool holders, as above described, are employed, one to thek eii'ect the Vpart of the tooth having the right-,handed sweep,v and therother for the left-handed sweep,l cach holder .being located about an appropriate axis ot' oscillation to effect this. The movementy of both tools would be timed so that they and their tool slides cleared one another throughout their respective travels. Y

What I claim as my invention and desire to secureLetters Patent of the United States Y l. The'r method ofV 'Generating bevel Gear b C 2D teeth, the sides of which describe Vcurves on' the pitch cone, which consists in giving a tool, having the shape of a tooth of the basic crown gear of the system, an oscillatory'cut-v ting motion across the face of the blank and simultaneously moving` said tool towards and away from its aXis of osciliatiomwhile giving the blankthe rotary and rolling motions a tool, representing a tooth of said crown gear, an oscillatory motion at right angles to said curves and simultaneously varying.

the radius of said oscillatory motion to cause the toolto follow said curves instead of circular arcs.

3. rlhe method ocutting bevelgears dac# cording to the generating system and soV that the teeth are longitudinally curved Vacross the face of the blank in other than circular arcs and are of uniform normal pitch 'from end to end, which consist in giving the blank, in addition to a rotation on its own axis, a rolling motion'about the axis of theimagif nary crown gear forming the basis of the-A system to which the gear being Vcut belongs, and givingthe tool,which has the shape of the teeth or said imaginarycrowngear, an oscillating cutting motion across the 'aceot the blank and simultaneouslyvarying the length of thel radius of oscillation.V

In testimony whereof I aihx mysignature.

HERBERT EDGAR, friiYLoa.

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