Improvements in Turning Lathes for Special Forms.
Year: 1896

page_text: Date of Application, 11th Jan., 1896-Accepted, 9th May, 1896
COMPLETE SPECIFICATION.
Improvements in Turning Lathes for Special Forms.
I, CHARLES ARTHUR ALLISON, Patent Agent, of 52 Chancery Lane, Loudon
in the County of Middlesex, do hereby declare the nature of this invention
(which has been communicated to me from abroad by The Garvin Machine Company
of No. 9 Laight Street in the City, County and State of New York, United
States of America), and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
SPECIFICATION.
"
This invention relates to machines for turning forms of desired outline from a
continuous bar of stock, and especially that class of such machines in which are
incorporated two sets of cutting tools to act on the stock from opposite sides of the
axis thereof, which is the plane of movement of the stock; and it consists of
certain novel features of construction for producing various advantageous results,
as hereinafter fully set forth.
In the accompanying drawings the machine is illustrated as follows:-
Figure 1 is a side elevation partly in vertical central section through the spindle
and chuck, showing the stock in position to be operated upon and the articles which
have been reduced therefrom. Means for cutting off these pieces of finished work
are not fully shown in this figure.
Figure 2 is a plan view of a portion of the machine shown in Figure 1 including
a piece of work as it appears in the process of reduction to the desired form.
Figure 3 is a view of the machine from the right hand end thereof as to Figures 1
and 2, showing the cutting off mechanism and other parts.
2
Figure 4 is an end view partly in vertical section, taken through the centre of
the tool-operating screw, showing the roughing and finishing tools, and the means
for their adjustment relatively to the stock to be operated upon, and other parts.
Figure 5 represents an end view and Figure 6 a side view of a modification in
the form of the cutter..
Similar letters of reference indicate similar parts in each of the figures.
The class of work which this machine is particularly designed to perform is that
in which a large portion of the work is turned off to produce forms as for example
hubs, which are in size and diameter within the limit of the original diameter of
the stock used.
:
In the operation of the machine the bar of stock S is passed through the hollow
spindle or mandrel A revoluble in suitable bearings and is held by the chuck C, as
best seen in Figure 1.
The chuck is provided with a differential screw consisting of an external and
internal thread on and in the plug a, these threads being of different pitch and
having corresponding threads in the body of the chuck C, and on the plug 6 that
bears on the jaw c, said plug & being kept from revolving with the plug a by the
screw, which enters a groove in the side of the said plug b. The set-screws c
bear through the opposite side of the chuck head, upon the opposite jaw of the
chuck, being thus adapted to thrust same forward, or, by their withdrawal, to allow
it to be drawn out to increase the capacity of the chuck.
The plug b bears on the jaw c at a point centrally between the respective
bearing-points on the jaw c¹ of the set-screws c³ c, so as to allow the jaw c to adjust
itself to the stock.

page_text: -
The tool-blocks B and E are cross-slides, and are gibbed to the slide-block Z,
and are operated in adjusting and feeding the tools by a right-and-left screw D.
This screw has, a direct connection with, and bearing in, the cross-slide E, but with
the slide B its connection is by means of the externally-threaded nut G, which is
screwed into the slide B, the external thread of the said nut being the reverse of
the internal, by reason of which turning the nut G will operate the slide B
independently of the opposite slide E, for the reason and purpose which will be
hereinafter stated.
The roughing tool consists of a number of cutters R, the cutting edges of which
may be of any desired form, but which are preferably, when allowable, square.
As to the form of the cutting-edges of the roughing tool, however, they should
approximately conform to the shape of the work to be turned, in order that they
shall reduce the stock so that a comparatively small cut of the finishing or forming
tool, on the part reduced by the roughing tool will form and finish the work after t
the roughing tool shall cease to cut. It is preferable that, as shown in Figure 2,
the roughing tool shall take off sections of the stock, turning grooves into the bar,
and leaving flanges between, which annular flanges are turned off by the finishing
tool; by reason of which construction the shavings of both tools are "broken up,"
or removed in narrow sections.
The finishing tool F is of the exact form that will shape the stock into the
desired finished form, thus completing the work. During the process of the
reduction of the stock, this finishing tool will operate on the surplus metal in form
of annular flanges left between the grooves made by the roughing tool, until the
roughing tool shall have finished its part of the work, when the roughing tool will
be withdrawn by turning the externally-threaded nut G and thus withdrawing the
slide B. This nut G, for the purpose of its operation, has attached thereto a
handle g, which is limited in its movement, and held firmly in its set positions by
the piston h, which is adapted to engage with holes z, in the face of the cross-slide B.
These parts just described are shown in Figures 1, 2, and 4.
The roughing tool is shown in Figures 1, 2, and 4, and as therein shown, the
cutters are shown to be clamped onto the tool-holder and cross-slide B, by means
of T-bolts and adjustable to and from its work by means of the nuts on the
ends of the hook-bolts J¹ set onto the tool-holder and moveable laterally with the
cutters. The annular flanges J2, on the said nuts, engage with the cutters forming
the compound roughing tool, by entering grooves J³ formed in the under edges of
said cutters, thus forcing same forward or back upon the revolution of said nuts on
said hook-bolts.
The radial adjustment of the finishing tool F as well as its attachment and
lateral adjustment on the tool-holder, is effected by the set-screws f¹, several in
number, bearing on the beyelled edges of the bracket Y by which the finishing tool
is carried; the looseness of the bracket in the tool-holder being sufficient to
permit any required adjustment by the set-screws. The finishing tool is sharpened,
when dulled by use, by grinding on its end; and for that reason, is of the
uniform shape required, being corrugated on its side for its whole length; so
that the shape of the cutting edge will not be altered by shortening it in
sharpening.
The right-and-left cross-feed screw D is driven by worm-gearing, which is itself
preferably driven from the machine. The journal-box i of the worm-shaft I,
having vertical movement in its housing, is shown in Figure 4. The worm is held
in mesh with its gear d¹ by means of the swinging-hook d that hooks outo the
journal-box i. Connected with the hook d is the rod r having an upwardly
projecting arm with which the adjustable stop s contacts, and, by its forward
movement, releases the box i and allows the worm to drop out of engagement.
This stop preferably consists of a bolt in a T-slot s', and should be adjusted to
cause the worm to drop out of engagement at the time the roughing tool shall have
performed its part of the work of reducing the stock, thus causing the tools to stop
cutting when the roughing tool should be withdrawn to a safe distance by means of

page_text: the externally-threaded nut G, as above described. The finishing tool will then
be operated by means of the crank N, or by a suitable wheel, on the screw D, until
it shall have turned off the annular flanges left by the roughing tool; and if
necessary, until the finishing tool shall have taken a light finishing cut over the
entire surface of the piece. Of course, on starting a new cut, the roughing tool
will be readjusted by means of the nut G to its original position.
This
While the operation of turning a piece of work is going on, the piece last formed
runs in the jaws K. and L. which act as a steady head for that purpose.
steady-rest in which the stock runs, is made necessary in this machine by reason of
the fact that when one of the tools, bearing on opposite sides of the stock, is
withdrawn, the pressure of the other tool still bearing on its side of the work
would obviously, without a steady-rest to prevent such result, throw the work out
of its true position and cause inaccuracies in shaping it. At the same time a saw k
carried in a frame that slides on the bar m, and is driven by the pitman.n
actuated by the crank-wheel o' on the shaft o, is cutting off the piece of finished
work from the bar of stock. As the process of the formation of a new piece is
going on at the same time that a piece already formed is being cut off, the jaws H
and J are so adjusted as to form a steady-head to steady the work under the saw,
as shown in Figure 3, being operated in adjusting by the right-and-left screw.v.
In practice, the operation of the reciprocating saw just described, is found to be
satisfactory, but it is evident that a circular saw operated preferably from the
machine, by suitable mechanism, to perform the same function, might be substituted
in its stead, without, in any material measure, departing from the spirit of this
invention.
After the finishing of each piece and the cutting off of one as described, the
machine is stopped and the jaws K and L are tightened on the place at which they
have acted as a steady-rest. The jaws of the chuck C are then opened and the
bar of stock is pulled out to the required distance to bring into position before, the
tools sufficient stock from which to form another piece. The chuck is then
tightened on.the stock, the jaws K and L are opened and carried forward and
closed on the piece just formed for the purpose of acting as a steady-head. To
prevent any accidental slipping of the stock that would impair the accuracy of its
position, on each presentation of a new portion to be operated upon, it will be
observed that either the jaws of the chuck or the jaws K and L are always
tightened on the bar of stock or on the work attached thereto, and that the
tightening or loosening of either is always done on one or the other of the
extremities of the movement that will now be described, the jaws K and L being
opened and closed by the right-and-left screw M.
The length axially of the article turned and to be removed from the stock is
determined by the extent of movement of the sliding carriage W, which forms the
support for the jaws K, L, serving to pull out the bar of stock by means of the
sliding carriage, and for the jaws H J that serve to sustain the work in the operation
of the cutting-off device. The sliding carriage W and its attached parts, are to be
moved back and forth by means of a rack U and pinion V, which is geared with a
crank or a suitable wheel; the said carriage having an appropriate guide on a
bolster Z, which is attached to the bed or frame of the machine.
The sliding carriage W is constructed to engage with the screw-threaded bar T,
and the latter has stops p q, preferably in the form of the nuts thereon, to co-act
with a lug t, which is integral with or attached to the sliding carriage for regulating
the adjustment of the carriage.
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:
1. In a turning lathe for special forms, the combination of a hollow revoluble
mandrel and a chuck thereon adapted to receive a continuous bar of stock, tool
blocks with tools adapted to act on the stock from opposite sides of the axis thereof,

page_text: a screw rod with a right and left hand member respectively engaging one of the
tool blocks for its adjustment in relation to the stock, a roughing tool on one
member of said tool blocks adapted to groove the stock circumferentially, a finishing
tool on the other member of said tool blocks adapted to remove the surplus metal
intermediate of said grooves of the stock and a steady-rest adapted to receive and
support the stock during the operation of the respective tools, substantially as and
for the purposes herein described.
2. In a turning lathe for special forms, a chuck composed of the two jaws which
are set diametrically opposite to each other in the head thereof, a differential screw
mechanism composed of a hollow plug having an external thread engaging with an
internal thread in a chuck head and having an internal thread of different pitch
from its external thread, engaging with an external thread on a secondary plug
inside of said hollow plug and bearing on one of said jaws, and a screw set into
said chuck head and bearing in a groove cut longitudinally of said interior plug.
to hold the same from revolving with said hollow plug during its operation, in
combination with a means for receiving and actuating a bar of stock through the
medium of the chuck and a steady rest adapted to receive and support the stock
during the operation of the roughing and shaping tools, said tools being located at
a point intermediate of the chuck and steady rest, substantially as and for the
purpose herein described.
3. In a turning lathe for special forms, the combination of the hollow revoluble
mandrel, the chuck thereon adapted to receive and actuate the bar of stock, the
rougbing tools and finishing tools adapted to act on the stock from opposite sides
therecf, a cutting off device on the machine frame adapted to operate simultaneously
with the roughing and finishing tools for separating successively from the stock
the finished article and a means for adjusting the stock in relation to said tools
and cutting off device, substantially as and for the purpose herein described.
4. In a turning lathe for special forms, the combination of the hollow revoluble
mandrel, the chuck thereon adapted to receive and actuate the bar of stock, the
roughing tools and finishing tools adapted to act on the stock from opposite sides
thereof, the cutting off device on the machine frame adapted to operate
simultaneously with the roughing and finishing tools for separating successively
from the stock the finished articles, the two sets of jaws for receiving the stock,
the sliding carriage supporting said jaws and a means for regulating the extent of
movement for said carriage, substantially as and for the purpose described.
5. In a turning lathe for special forms, a roughing tool and finishing tool
mounted on opposite slides and operated or fed forward by a right and left screw
engaging with the slides, the engagement with one of said slides being through a
nut which is also externally threaded and which is screwed into the slide, whereby
said nut is adapted to operate said slide independently of the turning of said right
and left screw, substantially as shown and described.
6. In a turning lathe for special forms, having a hollow spindle and a chuck
adapted to carry and drive the bar of stock to be operated on, tools for forming the
work and jaws operated by a right and left hand screw said jaws and screw being
mounted on a slide parallel with the axis of the hollow spindle and chuck, said
slides being actuated by a suitable mechanism and governed in its movements by a
Jug attached to said slide and by stops attached to the stationary part on which
the slide moves and adapted to contact with said lug, substantially as shown and
described.
Dated this 11th day of January 1896
ALLISON BROS.,
Agents for the Applicant.