Year: 1886

page_text: Date of Application, 12th June, 1886.
Complete Left, 12th Mar., 1887.
Complete Accepted, 19th Apr., 1887.
I CHARLES LEIGH CLARKE of 75 York Street Cheetham Hill Manchester in the
County of Lancaster Engineer do hereby declare the nature of this invention to be as
follows:-
This invention relates principally to the construction of that class of lathes known
as "capstan lathes" wherein the tool carriers revolve upon a kind of capstan so as to
present different tools as may be required, but a portion of the said invention which
relates to the cutting of screws is also applicable to other descriptions of screw cutting
lathes.
The first part of the invention relates to the tool carriers the object being to enable
the same to be set nearer to or further from the centre of the capstan head without
disturbing the position of the tool in the carrier and also to provide a ready means of
moving and fixing the capstan head so as to present the tool required and hold it
firmly in place.
This I effect by cutting parallel diagonal slots in the foot of the tool carrier
through which the bolts or set screws pass, which attach the carrier to the capstan
head, so that by loosening the nuts or screws the tool carrier can be set to the required
position without disturbing the tool.
The capstan head is provided with a series of notches into one of which takes a
spring catch constructed as follows.
A projection is formed upon a curved lever pivotted to the slide which latter is
also provided with a projection bent upwards so as to leave a space between it and
the curved lever into which works a sliding wedge or shoe piece. This shoe piece
is attached by a pin to a second lever which is pivotted to the curved lever above
named and provided with a spring bearing against the said curved lever in such
a way that the wedge or shoe piece is held tightly between the projection on the
slide and the curved lever, and the projection on this lever is consequently held firmly
in one of the notches in the "Capstan head," and the required tool is kept in position.
The capstan head may also be made adjustable vertically for cutting angular faces.

page_text: The second part of my invention (which is also applicable to other forms of lathe)
relates to an arrangement for cutting a screw upon an article up to a shoulder or a
certain fixed distance on a cylindrical piece.
For this purpose the chasing tool is required to travel longitudinally at a certain
speed for a certain fixed distance whilst the article revolves against it and then to stop
and instantly travel back whilst the revolution of the article is at the same time reversed.
The traversing to-and-fro of the tool I effect in the usual manner but the reversing
of the motion of the spindle I obtain as follows.
Upon the running spindle of the lathe I key a double cone pulley running between
two internal cones inside the rims of two grooved driving pulleys which run in
opposite directions and slide upon the spindle. These pulleys are both moved by one
double lever so that as one is moved into contact with the double cone the other
is moved out of contact and thus the spindle is driven forwards or backwards
according as one or other of the cones is moved into or out of gear. These grooved
pulleys are connected to a lever which lever is actuated by a sliding piece provided
with a pin running against a cam surface or in a groove on a drum cast to the face of
a toothed wheel which is driven by a spur pinion on the end of the lathe spindle.
As this cam revolves it causes the lever to hold either one or other of the pulleys
into gear with the cone, but as soon as the chasing tool has reached the required limit
an inclined part of the cam or groove acting on the lever causes the latter to put the
other pulley into gear with the cone and thus reverse the motion of the spindle whilst
the traverse of the chasing tool is at the same time reversed also.
I prefer to fix the cam surface in a groove in the periphery of the drum so that it
may be removed and another substituted according to the length of screw required.
By employing two tool carriers both attached together and working on one slide
two screws may be cut at the same time one upon each end of the same cylinder.
Dated this 11th day of June 1886.
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicant.

page_text: I CHARLES LEIGH CLARKE of 75 York Street Cheetham Hill Manchester in the
County of Lancastor 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 relates principally to the construction of that class of lathes known
as Capstan lathes' wherein the tool carriers revolve upon a kind of capstan so as to
present different tools as may be required, but a portion of the said invention which
relates to the cutting of screws is also applicable to other descriptions of screw cutting
lathes.
The nature of my said invention and the manner in which the same is to be carried
into practical will be readily understood on reference to the annexed sheet of drawings
and the following explanation thereof.
Fig. 1. is a detached plan view of one of the tool carriers.
Fig. 2 is a plan view of part of the capstan head and spring catch hereinafter
referred to.
Fig. 3. is a side elevation of so much of a complete lathe as is necessary to illustrate
my invention and
Fig. 4. is a diagrammatic development of the cam surface hereinafter mentioned.
The first of the invention relates to the tool carriers a, a Fig. 1, the object being
to enable the same to be set nearer to or further from the central line of the capstan
head b,b (Fig. 2) without disturbing the position of the tool c, c in the carrier a, a
and also to provide a ready means of moving and fixing the capstan head b, b so as to
present the tool required and hold it firmly in place.
This I effect by cutting slots d,d in the foot of the tool carrier a, a through which
the bolts or set screws pass, which attach the carrier to the capstan head b, so that
by loosening the nuts or screws the tool carrier a a can be set to the required position
without disturbing the tool c, c.
The capstan head b, b (Fig. 2) is provided with a series of notches e, e into one of
which takes a spring catch constructed as follows.
A projection, is formed upon a curved lever g,g pivotted to the slide h, h which
latter is also provided with a projection i, i bent upwards so as to leave a space
between it and the curved lever g, g into which works a sliding wedge or shoe
piece k,k. This shoe piece k, k is attached by a pin to a second lever 1, which is
pivotted to the curved lever g,g above named and provided with a spring m, m
bearing against the said curved lever g,g in such a way that the wedge or shoe
piece k, k is held tightly between the projection i, i on the slide h, h and the curved
fever 9.9
and the projection ff on this lever is consequently held firmly in one of
the notches e, e in the "capstan head," and the required tool is kept in position.
The capstan head may also be made adjustable vertically for cutting angular faces.

page_text: The second part of the invention (which is also applicable to other forms of lathe)
relates to an arrangement for cutting a screw upon an article up to a shoulder or a
certain fixed distance on a cylindrical piece.
For this purpose the chasing tool is required to travel longitudinally at a certain
speed for a certain fixed distance whilst the article revolves against it and then to stop
and instantly travel back whilst the revolution of the article is at the same time
reversed.
The traversing to-and-fro of the tool I effect in the usual manner but the reversing
of the motion of the spindle I obtain as follows.
Upon the running spindle n, n Fig. 3. of the lathe I key a double cone pulley o, o
running between two internal cones inside the rims of two grooved driving pulleys p, p,
which run in opposite directions and slide upon the spindle n, n.
These pulleys are both moved by one double lever q, q so that as one is moved into
contact with the double cone o, o the other is moved out of contact and thus the
spindle n, n is driven forwards or backwards according as one or other of the internal
cones pp is moved into or out of gear. These grooved pulleys p,p are connected by
a double lever q, q to a lever r, which lever is actuated by a sliding piece s, s pro-
vided with a pin t, running against a cam surface u, u (or in a groove) on a
drum v, v cast with or attached to the face of a toothed wheel ww which is driven
from a spur pinion on the end of the lathe spindle.
As this cam u, u revolves it causes the levers 7, 9 and r, r to hold either one or
other of the pulleys pp into gear with the cone o, o but as soon as the chasing tool
has reached the required limit an inclined part u, u of the cam or groove acting on
the lever, causes the lever 7,7 to put the other pulley into gear with the cone 0,0
and thus reverse the motion of the spindle nn, whilst the traverse of the chasing tool
is at the same time reversed also.
I prefer to fix the cam surface u¹, u₁ in a groove in the periphery of the drum so
that it may be removed and another substituted according to the length of screw
required.
By employing two tool carriers both attached together and working on one slide
two screws may be cut at the same time one upon each end of the same cylinder.
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 :-
First. The construction substantially as described and illustrated for adjusting the
tool carrier.
Secondly. The combination with a capstan head having circumferential notches of
a spring catch lever and its adjuncts (or its equivalent) substantially as hereinbefore
described and illustrated by the drawings annexed.
Thirdly. The construction of apparatus substantially as herein before described for
reversing the direction of revolution of the lathe spindle when chasing screws up to a
shoulder or fixed point.
Dated this 11th dow of Mauch 1007
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicant.