Improvements in Apparatus for Cutting Teeth in Wheel Blanks or the like.
Year: 1893

page_text: Date of Application, 13th May, 1893
Complete Specification Left, 12th Feb., 1894-Accepted, 17th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Cutting Teeth in Wheel Blanks
or the like.
A communication by CONRAD M. CONRADSON of Madison, in the County of Dane
and State of Wisconsin, United States of America, Mechanical Engineer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323 High Holborn, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this inven-
tion to be as follows:-
This invention has for its object an apparatus for cutting teeth in wheels. Gear
blanks are usually bored, faced and turned on the outside in a lathe before being
cut in a gear cutting machine; but under the present invention it is proposed to
bore and face the blanks on the two sides in any suitable manner and then cut the
teeth and finish the outside simultaneously by the use of a special gear cutter.
In carrying the invention into effect, a rotary gear cutter is provided, having two
cutting bits adapted to rotate in unison, one of said bits conforming in shape to the
curved sides of two teeth and the intervening base, and the other bit conforming in
shape to the ends of the teeth, whereby the teeth and intervening base are shaped,
dressed and finished at one operation. This invention also comprises the combi-
nation, with side and top face gear cutters conforming in shape to the sides and ends
respectively of the teeth to be cut, of a common carrier for the same, the said
cutters being arranged thereon to simultaneously cut the side and top faces of the
gear teeth.
CM 1002
WM. P. THOMPSON & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Cutting Teeth in Wheel Blanks
or the like.
A communication by CONRAD M. CONRADSON of Madison, in the County of Dane
and State of Wisconsin, United States of America, Mechanical Engineer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.J.M.E., of the Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool and 6 Bank Street
Manchester both in the County of Lancaster and 323 High Holborn in the County
of Middlesex, Civil Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
This invention has for its object an apparatus for cutting teeth in wheels. Gear
blanks are usually bored, faced and turned on the outside in a lathe before being cut
in a gear cutting machine; but under the present invention it is proposed to bore
and face the blanks on the two sides in any suitable manner and then cut the teeth
and finish the outside simultaneously by the use of a special gear cutter now to be
described in detail in connection with the accompanying drawings, in which,

page_text: Figure 1 is a longitudinal sectional view of the improved cutter as it appears at
work; and
Figures 2 and 3, similar views, illustrating slight modifications in the construction
or arrangement of the same.
A, indicates a shaft or arbor journalled in suitable bearings and adapted to be
rotated in the same manner as in the ordinary form of gear cutting machines.
Mounted upon this shaft or arbor and keyed or otherwise rigidly affixed thereto,
is the improved cutter B, which, in the preferred form, as shown in Figure 1,
comprises the progressive cutting heads C, D and E, and a finishing cutting head F,
which latter is designed to give to the teeth the desired form and final dressing.
The cutter comprising the cutting heads C, D, E and F, may be made of a single
integral piece of metal as shown in Figure 1, or the bits may be made separate as
indicated by dotted lines in said- figure, and keyed or otherwise rigidly secured
upon the shaft or arbor, so that under all circumstances the different parts of the
cutter must be rotated or revolved in unison.
The cutting head C, which first acts upon the blank, cuts a V-shaped notch in
the periphery of the wheel, while the cutting head D, which is narrower than the
cutting head C, works in further toward the centre of the gear blank and enlarges
the opening made by the cutting head C.
The cutting head E more nearly resembles in form the space between the teeth,
and enlarges the opening or notch previously formed by the cutting heads C
and D.
The part F is provided with a central cutting bit a of a form in cross section
corresponding exactly to the space between two teeth, and with cutting bits or
shoulders and c of different sizes located respectively on opposite sides of the
central cutting bit a.
The cutting bit 6 works upon the end of the teeth and removes a portion of the
inetal therefrom, while the cutting bit c operates upon the end of the tooth
previously operated upon by bit b, and gives to the end of the tooth the finishing
dressing. These bits or shoulders b c are made of different sizes and arranged to
act successively upon the end portions of the teeth in order that the operations of
cutting and dressing the ends may be rendered gradual instead of throwing the
entire work upon the single bit or cutter c, as is done under the arrangement shown
in Figure 3.
From this construction it will be seen that the single tool accomplishes at one
and the same time the forming and dressing of the sides and the ends of the teeth,
and also the base or that portion between two adjacent teeth, a result not hitherto
accomplished.
The construction shown in Figure 1, and just above described, is particularly
useful in cutting heavy gears where it is not desired to throw the entire work of
cutting, shaping and dressing the teeth upon the single cutting head F, the action
of the progressive cutting heads C, D and E rendering the work of the cutting
head F easier than if the latter were compelled to do the entire work itself.
For lighter work, however, it is proposed to omit the progressive cutting
heads C, D and E, and employ simply the cutting head F, as shown in Figure 2;
the said cutting head under such an arrangement being provided with the central
cutting bit a and the cutting shoulders or bits b and c.
If desired, the cutting shoulder & may be omitted and only the cutting bit a and
the shoulder c be employed. Under this arrangement, which is illustrated in
Figure 3, the cutting bit c may be set away from the cutting bit a the distance of
a tooth, and may be made either integral with the cutting bit a or separate there-
from; but in any event it must be so arranged as to rotate in unison therewith in
order that the operation of shaping and finishing all parts of the tooth may be
accomplished at one and the same operation.
It is admitted that it has been proposed to employ in the manufacture of gear
wheels separate and independent male and female cutters wholly disconnected from
cach other, the former adapted to cut on the radial centre lines of the space and

page_text: give form to its sides up to the pitch line of the gear, and the latter (the female
cutter) adapted to work on the radial centre line of a tooth and finish the form of
both sides of the tooth down to the pitch-line.
It is also admitted that in order to make a fly cutter or a very fine pitch or gear
tooth such as used for watches, it has been proposed to make a template of such
form as to fill a space and a half of each of the neighbouring teeth. To such
constructions as these no claim is made.
Under both of these plans, however, to which allusion has been made, it is necessary
to go completely over the gear wheel at least two times in order to give the desired
form to the teeth, whereas under the construction and arrangement according to the
present invention the wheel is rendered complete, that is to say, its teeth and
intervening, spaces are shaped, dressed and finished all at one operation, a result
which it is believed has not heretofore been accomplished.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is-
1. A rotary gear cutter provided with two cutting bits adapted to rotate in
unison, one of said bits conforming in shape to the curved sides of two teeth and the
intervening base, and the other bit conforming in shape to the ends of the teeth, all
substantially as shown and described, whereby the teeth and intervening base are
shaped, dressed and finished at one operation.
2. In a gear cutter, the cutting head F provided with a central bit a and the
different sized cutting shoulders or bits b and c located upon opposite sides of the
central bit and adapted to act successively upon the end of each tooth.
3. In a gear cutter, the combination, with the cutting head F having the
bits a b and c, of the progressive cutting heads C, D and E, the said cutting
heads C, D, E and F being adapted to rotate in unison, all substantially as shown
and described.
4. The combination, with side and top face gear cutters conforming in shape to
the sides and ends respectively of the teeth to be cut, of a common carrier for the
same, said cutters being arranged thereon to simultaneously cut the side and top
faces of the gear teeth substantially as described.
Dated this 10th day of February 1894.
WM. P. THOMPSON & Co.,
Agents.