Milling-cutters.
Year: 1890

page_text: Date of Application, 4th Sept., 1890-Accepted, 25th Oct., 1890
Milling-cutters.
I, CHARLES C. TYLER, of No. 15 Chestnut Avenue, in the City of Waterbury,
County of New Haven, State of Connecticut, one of the United States of America,
Watch-tool Maker, do hereby declare the nature of my invention for MILLING-
CUTTER, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention relates to milling-cutters for cutting the teeth of gears and pinions ;
the object being to furnish a cutter for said purposes having superior qualities and
adapted to be produced with precision and economy.
In the drawing accompanying this Specification,
Fig. 1 is a side elevation, drawn on an enlarged scale, of a partly-formed milling-
cutter made according to my invention: and it illustrates in part the method of forming
by compression the cutting teeth on the cutter.
Fig. 2 is an edge view, partially in section, further illustrating my improvements.
Fig. 3 is a side elevation, on a smaller scale, of a complete milling-cutter.
Similar characters designate like parts in all the figures.
In making my improved milling-cutters, I ordinarily use an over-size blank, only
approximately shaped, and reduce the same to the required size simultaneously with
and by the forming of the teeth on said blank. By this means, in making smaller
cutters, for which my said improvement is more particularly adapted, the blanks may
be first cut out by means of cutting dies from sheet-metal of suitable quality, and
afterward cut or toothed," without any other intermediate preparation than forming
therein the usual central hole for the cutter-carrying arbor. By this method or process
I am able to produce my improved milling-cutters of a high quality and precision, at
a very low cost, and very uniform in size and shapo.
The instrumentality by means of which I ordinarily practise my invention, consists
of a tooth-forming compressor-tool, T, having on its working face, 20, a conforma-
tion coinciding with the form of tooth to be made. This tool, when making circular
cutters of a required size from an over-size blank, is always limited in its working
stroke to stop at a certain precise distance from the centre of the cutter.
In another application for British Letters Patent, I have described a machino
suitable for operating said tooth-forming tool for the making of the cutters. The
cutting-tooth formed by said tool has a substantially uniform cross-sectional dimension
throughout the length thereof, and is set or formed on the cutter to have a decreasing
radius from the point backward therefrom, one tooth extending from its own point
backward toward the cutting-face of the next succeeding tooth.
The operation of forming a tooth consists in the compression of the blank, unheated
and in its natural condition, by a suitable instrumentality, in a direction cross-wise to
the line of the points of the cutting-teeth, and at such an angle thereto as is proper
to form the required relief or "backing-off" for the tooth, by a movement of the said
tool in a direction parallel to the cutting-face of the tooth formed by said movement.
This having been done once, as at 12, the blank is advanced (relative to such
instrumentality) and another compression similarly effected. When an over-size
blank is used, as shown in Fig. 1, the line 45 of the final compression extends from
the root, 39, of the tooth 40, upward and forward to the intersection, 41, with the
line, 13, of the points of the cutting-teeth; and beyond point 41 to the periphery, 44,
of the blank. The blank is now advanced through the arc (or space) from point 39
to point 41, Fig. 1, and the operation repeated. It will then be seen that the true
size of the cutter is a line extending through the points, 41, of the cutting-teeth;
and that the position of these points is determined by the angle of said line 45,
and by the distance through which the blank is advanced between the successive
compressions.

page_text: It has been customary, hitherto, to make cutters of this class of sheet-metal, by
first cutting out and contrally perforating the blank, and then shaping the teeth by a
delicate and expensive process of milling off the superfluous metal. In my improved
sheet-metal cutter herein described, the said surplus of peripheral metal is not removed,
but is disposed around the cutter on the sides thereof, in the form of laterally-
projecting rings, substantially as shown, whereby the bases of the entting-teeth are
broadened, while the middle portions of the disk remain of a flat form, and
unchanged in character.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
The improved milling-cutter herein described, it consisting in a disk having
cutting-teeth substantially as described on the periphery thereof, and ordered by
the surplus peripheral metal disposed into Interally-projecting rings, whereby the bases
of said teeth are broadened, substantially as set forth.
Dated this 17th day of July 1900
CHARLES C. TYLER.