Improvements in Scape-wheels for "Duplex" Watch-escapements, and the Manufacture of such Scape-wheels.
Year: 1894

page_text: Date of Application, 6th Mar., 1894-Accepted, 21st Apr., 1894
COMPLETE SPECIFICATION.
Improvements in Scape-wheels for "Duplex" Watch-escapements,
and the Manufacture of such Scape-wheels.
A communication from abroad by EDWARD AUGUSTUS LOCKE, of 6, Monmouth
Street, Brookline (Boston), in the State of Massachusetts, United States of
America, Manufacturer.
I, JOHN CORRY FELL, of the Firm of Fell and Wilding of 1 Queen Victoria
Street in the City of London, Chartered Patent Agent, do hereby declare the
nature of the said invention for "IMPROVEMENTS IN SCAPE-WHEELS FOR
66 'DUPLEX" WATCH ESCAPEMENTS AND THE MANUFACTURE OF SUCH
SCAPE-WHEELS," and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Heretofore the "scape-wheels" of all duplex escapements, except those the teeth
of which are laboriously shaped one by one by hand, have of necessity been made
of soft brass so as to provide for forming the "impulse teeth" in dies or for bending
them to bring them into their different plane as compared with the spur teeth or
"long teeth.'
Consequently such scape-wheels have had to be made comparatively
heavy, in order that the delicate long teeth might resist their contacts with the
balance-arbor, and are peculiarly liable to become bent, in the hauds of watch-
makers, so as to become inoperative.
The present invention consists primarily in a peculiarly constructed hard-metal
scape-wheel for duplex escapements, as a new manufacture, the same being adapted
to be cheaply made by machinery exclusively, with the highly desirable absolute
uniforinity thus obtainable, and at the same time to be made of exceedingly light
weight, so as to oppose less inertia to the movement of the train than machine-made
scape-wheels as heretofore constructed.
The invention further consists in a novel process whereby such superior scape-
wheels of shape-preserving hard-metal and of light weight may be manufactured
exclusively by machinery, and in a certain novel portion of such process, as herein-
after set forth and claimed.
A sheet of drawings accompanies this Specification as part thereof.
Figure 1 of these drawings comprises a face-view and a diametric section of a
circular blank produced by lathe-turning, illustrating the first stage of said
process; Figure 2 is a face-view illustrating its second stage;
Figure 3 is a face-view, with appended representations of milling cutters, in
dotted lines, illustrating the third and fourth stages of the process ;
Figure 4 is a face-view of the finished scape-wheel; and
Figure 5 is a fragmentary elevation. showing the scape-wheel in section on the
line 5-5 Figure 4.
Like reference letters and numbers refer to like parts in all the figures.
The blank A, Figure 1, is produced by lathe-turning, and consists of a flat
circular disc having a central hub-projection 1 and a concentric annular flange 2,
preferably on one and the same side of the body of the disc, which extends beyond
said annular flange in the form of a wide margin 3.
66
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The blank is next passed to a punch and die of the pattern indicated by Figure 2,
which represents their product. The blank as thus "roughed out" has the spokes
4 of the final product B, Figure 4, together with its rim 5, except the
peripheral surfaces of the latter, and also the long teeth 6 in rough; the latter
being formed from said margin 3, Figure 1, by removing the interdental portions
or cross

page_text: thereof; while said cross and-rim are formed by punching out portions of the body
of the disc, Figure 1, between said hub-projection 1 aud annular flange 2. The
latter, 1 and 2, are left untouched by the punch and die.
A number of roughed out blanks, Figure 2, are next assembled in a "stack," and
subjected to the action of one or more suitable milling cutters C, Figure 3, by
which the long teeth 6 are shaped as to the front and back of each tooth, and the
intermediate impulse teeth 7 are formed or completed, at one and the same pro-
gressive milling operation; said impulse teeth being cut from that portion of the
blank, Figure 1, which is provided with said annular flange 2, so as to project
above the plane of said long teeth to a second plane, as required in duplex escape-
ments, without any displacement of the metal of the teeth.
;
Functionless portions of said annular flange 2 remain on the long teeth, as at 2
in Figure 3. To remove these portions, each scape-wheel is next subjected to the
action of an annular milling cutter C, Figure 3. This cutter removes said
functionless portions of the flange 2 from two of the long teeth 6 simultaneously,
as illustrated in Figure 3, and thus rapidly completes the teeth of the scape-wheel.
The bore 9, Figure 4, of its hub 1, is next drilled, which completes the scape-wheel
as represented by Figure 4.
The product of the above process is distinguished from other machine-made
scape-wheels for duplex escapements by being of light weight and of! hard metal
as aforesaid, and furthermore by having impulse teeth which project bodily from
the periphery of the rim of the wheel and extend upward to a plane above that of
the long teeth by being of extra thickness or width from bottom to top, as seen in
Figure 5. D in this figure (Figure 5) represents an ordinary arbor on which the
improved scape-wheel is mounted, E a balance-arbor parallel therewith, and Fa
middle portion of the balance-wheel.
i....
The improved :scape-wheel B is or may be adapted to co-operate with any
ordinary or improved balance-arbor and balance-wheel, and comprises, as shown in
the drawings, eight ordinary long teeth 6 and eight intermediate impulse-teeth 7;
all the teeth project from the periphery of a flat rim 8, said long teeth lying in the
plane of the rim, while said impulse teeth, being of greater thickness or width from
bottom to top as aforesaid, extend upward to a second plane according to the
requirements of duplex escapements; and said rim 8 is connected by a cross 4,
which is conveniently and preferably of the same thickness as the rim and long
- teeth, with a drilled hub 1, which is conveniently and preferably of the same
thickness as the impulse-teeth.
:
Said long teeth are thus adapted to engage successively with the balance-arbor
or a hub thereon and with its customary notch 10, and said impulse-teeth to engage
successively with an impulse-pallet 11, or its equivalent, carried by said, arbor in
customary manner.
The number of teeth of the improved scape-wheel may be increased or lessened,
the impulse-teeth may project downward instead of upward, and other like
modifications will suggest themselves to those skilled in the art.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
11
i.
(1.) As a new manufacture, a hard-metal scape-wheel, for duplex escapements,
having long teeth in the plane of its rim, and intermediate impulse-teeth, of greater
thickness or width from bottom to top as compared with said long teeth, projecting
bodily from the periphery of said rim, and extending upward to a second plane as
required, substantially as hereinbefore specified.
(2.) The method of making hard-metal scape-wheels, for, duplex: escapements,
which consists in providing a blank with a hub-projection an annular flange and a
wide margin external to said flange by lathe-turning; producing the cross and rim,
except as regards the peripheral surfaces of the latter, and, also roughing out the
long teeth, by a punching operation; cutting all the teeth in the, stack by cuts
17

page_text: extending inward through said flange; milling off the functionless remnants of said
flange; and, finally, drilling the hub of the wheel, substantially as hereinbefore.
specified.
(3.) In making hard-metal scape-wheels for duplex escapements, the method of
forming the teeth which consists in providing the blank with an annular flange and
a wide margin external to such flange by a lathe-turning operation, roughing out
the long teeth from said margin by punching, and cutting all the teeth in the stack
by cuts extending inward through said flange, substantially as hereinbefore
specified.
Dated at London 28th February 1894
FELL & WILDING,
Agents for the Applicant.