IMPROVEMENTS IN AUTOMATIC LATHES
Year: 1883

page_text: LETTERS PATENT to Frank Wirth of the firm of Wirth and Company
Patent Solicitors, at Frankfort on the Main, in the Empire of Germany for
an Invention of IMPROVEMENTS IN AUTOMATIC LATHES a communication
from Eduard Heinrich Freter a person resident at Roedelheim near Frankfort
on the Main in the Empire of Germany
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office
of the Commissioners of Patents on the 25th May 1883.
"
FRANK WIRTH, of the firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Main, in the Empire of Germany,
IMPROVEMENTS IN
AUTOMATIC LATHES." A communication from Eduard Heinrich Freter a person
resident at Roedelheim near Frankfort on the Main in the Empire of Germany.
The said invention relates to an automatic machine tool or lathe, particularly
applicable to the production of screws.
The machine consists of a bed upon which rests a hollow head-stock rotated by
a belt and coned pulley from a convenient driving power.
Upon the head stock shaft is fixed an eccentric and pawl engaging into a ratchet
wheel, which by a suitable counter shaft and gearing, operates a shaft passing
through the saddle under two sliding tool rests.
Upon this transverse shaft are two grooved cams, one under each rest, into which
project pins, one from each sliding tool rest respectively. The grooves in the said
cams are so formed as to bring forward and retire the tool rests to and from the
work or wire, successively, the one to shape out the screw and bead, and the other
to cut the screw off when complete.
On the front end of the head stock spindle is fixed a chuck provided at its centre
with two sliding jaws, to grip the wire or rod passed through the head-stock. The
said jaws are pressed together so as to grip the wire by a cam lever projecting
beyond the rim of the chuck and passing through a slot in a semicircular movable
rim. Another projecting lever is fitted to the chuck and is provided with a few
teeth where it engages into the movable rim. Any movement then of the second

page_text: lever moves the sliding rim and consequently the other cam lever, pressing or
releasing the dies so as to grip and set free the wire, according to the direction of
movement.
As the head-stock revolves these levers are arranged to strike upon two sliding
pieces, brought into action, when required, by a lever and cam motion upon the
transverse shaft under the tool-rest saddle. The wire is thus alternately gripped
and released at the commencement and end of the operation. When released the
wire rod is fed forward through the hollow spindle by a known weight and pulley
feed.
The foregoing apparatus provides an automatic feed, an alternate automatic grip
and release in the head-stock, and an automatic alternate movement of two
slide tool-rests to shape and cut off the finished screw. The screwing apparatus
is as follows :-
The screw cutting dies are held in the mouth of a hollow spindle, carried in
another head-stock, face to face with the first, and provided with a loose pulley
and friction clutch, so that it can be rotated by a belt when the clutch is in gear.
When the screw is being cut the die spindle is held at rest, by a projecting lug,
the clutch being out of gear. The clutch is automatically thrown into gear and
the die spindle revolved in the same direction as that of the wire, but at a faster
speed, in order to disengage the dies after the screw has been cut.
The die spindle can slide forward towards the head-stock and is brought back
by the re-action of a spiral spring.
To effect the automatic action of this screwing tackle a geared wheel is fixed on
the aforesaid transverse shaft under the tool-rest slides, and by a suitable train
operates a cam wheel, upon which are a series of fingers to effect the successive
operations.
The die spindle is connected with a parallel rod by a suitable fork so that they
move together. The rod is fixed over the afore-said last wheel of the train and is
provided with a projecting lug against which the cam fingers operate. As the
wheel rotates the die-spindle is first pushed forward so as to push the wire back in
the head stock to the exact length of screw required. After the wire is gripped
in the chuck, the dies are again thrust by a second finger on to the end of the rod
so as to bite with the thread, which then screws itself along the rod, the projecting
lug of the die spindle still resting on a catch and preventing rotation.
A further finger on the revolving wheel now pushes the spring pressed catch
from under the lug and at the same time the friction clutch on the die spindle is
put into gear. The dies thus disengage themselves and the spindle is drawn back
by a spring or other suitable means. The cutting tool then comes forward and
cuts off the finished screw.
The whole process is then again repeated.
The grooved cams operating the slide rests, the projecting lug on the die spindle,
and the automatic gearing, may be changed or adjusted to produce any desired
variations in the form and size of the screws.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frank Wirth in the Great Seal Patent Office on the 24th November
1883.
IN
FRANK WIRTH, of the firm of Wirth and Company, Patent Solicitors, at
Frankfort on the Main, in the Empire of Germany "IMPROVEMENTS
AUTOMATIC LATHES."-A communication from Edward Heinrich Freter a person
resident at Roedelheim near Frankfort-on-the-Main in the Empire of Germany
The said invention relates to an automatic machine-tool or lathe, particularly
applicable to the production of screws.
In order that the said invention may be clearly understood, and the method
of carrying the same into effect, I now proceed to describe the same, reference
being bad to the drawings hereto attached and to the letters and figures marked
thereon.
Like letters refer to similar parts in the different figures.
Figure 1 is a plan and Figure 2 an elevation of the complete lathe.
Figure 3 is a detail of the eccentric pawl feed.
Figure 4 is a detail of the gripping chuck.
Figure 5 is a detail of the cain or finger wheel P
Figure 6 is a cross section of the saddle and tool rest.
Figure 7 is a plan and Figure 8 an elevation of the saddle cam shaft J.
Figure 9 is a detail of the lug and detent on the die spindle.
Figure 10 is a detail of a pin movement operating the gripping chuck.
Figure 11 is a detail of the detent v.
Figure 12 is a detail of the weight and pulley feed to the wire.
The hollow spindle A rests in the bearing blocks B (thus constituting a hollow
headstock) so that it can be rotated by means of the stepped or coned pulley C
and a belt, either from power shafting or direct from a motor.
The eccentric D ends in a pawl, engaging into the teeth of the ratchet wheel E,
so that every rotation of the spindle A moves the ratchet wheel E to the extent of
one tooth.
On the front end of the spindle is screwed the chuck F. Figure 4 shows this
chuck after removal of the plate which closes it in front, and which has in the
centre a small hole for the wire to be operated upon.
The lever h, free to turn around an axis, is situated in a recess a, the depth of
which equals the thickness of the lever. At the end nearest to the axis this lever
is expanded into a circular boss, thus pressing together the sliding jaws b b which
hold the wire, led through the hollow headstock A B. This boss is not circular
all round, but flattened at one part, as shown in the drawings; when the flattened
part is exactly over the jaws bb, the latter are no longer pressed together and can
be more or less pushed apart.
Another lever, which rests in a projection d on the circumference of the
chuck, is supplied at one end with a toothed segment.
Around the chuck is placed the semi-circular moveable rim or half-ring, held
by the transverse-piece c and the projection d, so that it can move on the chuck to
and fro. This half-ring is supplied at one side with a forked piece g, engaging
he lever h, so that when the latter is moved, a corresponding motion of the half-
ing is effected. It is supplied with holes o at one end, into which engage the
eeth of the segment of the lever h¹; thus by a movement of this lever the half-
ing is also moved.
Under the holders H, which are on the slide rest G, are to be screwed
he tools.

page_text: The upper part ƒ of the slide rest (Figure 6) is moveable by means of the
handle, and the whole slide-rest is moveable on the dove-tailed saddle U.
Figure 7 is a plan of this saddle seen from underneath.
On the axle J are fixed the bevel-wheel K, the grooved cam L, and the gearing
wheel M.
To the bottom of the slide rest G is fixed a pin l, the free end of which engages
into the groove of the cam L, so that a revolution of the latter effects a to-and-fro
movement of the saddle corresponding to the groove. The wheel M gears into the
wheel R and the revolution of the former is transmitted by the latter to the
wheel R', and then to the wheels R, R, and P. The wheels R, R¹, R¹¹ freely
revolve around axes which are situated on the lathe-bed, and the wheels R¹ and
P on axes situated on the second adjustable headstock B¹.
When a revolution of the axis A, by means of the pawl D, effects a partial
revolution of the ratchet wheel E, this rotation is transmitted by the bevel-wheel K¹
(which is fixed to the same axis J' as the ratchet wheel E) to the bevel-wheel K
and thence to the wheel P.
To the shaft J (Figure 7) are further fixed two cams Q (Figures 6, 7, and 8)
which, when rotated, press upon the levers R, which are free to turn around an
axis (Figures 6 and 10), thus lifting the sliding pieces S, situated in the saddle U,
and moveable upwards or downwards. These sliding pieces are supplied with
small pulleys at their upper ends, and, as soon as the pressure from the lever R
(or the cams Q respectively) decreases, they are pressed back by springs.
When one or the other of these sliding pieces is lifted by the lever R, resistance
is offered to the lever h (or ¹ respectively) which rotates with the chuck F,
whereby the chuck is either closed or loosened; that is to say, it is closed when the
lever strikes against the respective sliding piece, but when the lever h¹ finds the
respective resistance, the chuck is loosened, because with the lever his moved
the half-ring r, and thus the lever h as well, so that the pressure exerted by the
latter upon the jaws bb is taken off, and the latter are set free.
The screw cutting dies in spindle W rest on the second head-stock B' B' and can
be pulled forward in the direction of the arrow, but, as soon as set free, they are
brought back into their former position by springs.
On the second head-stock rests also the pulley T with a hollow axis free to
turn around the die spindle W, but not moveable sidewards. There is further
situated on the die spindle W, also with hollow axis, moveable sidewards, but not
free to turn, the friction plate V. Around the end of this axis is the groove n.
Into the groove n engages the fork m fixed to the parallel rod O which is
moveable to and fro on a fixed rest and guided by slots p p.
From the underside of the rod O projects a lug q. On the die spindle W is a
projecting lugt to which is screwed the piece g' having a projection and being
adjustable (Figures 1 and 9). By this lug t the die spindle, in its usual position,
rests upon the catches u and v, which are moveable around an axis and situated on
a fixed rest.
The catch u engages with the rod O by a joint so that the same, when the
latter is pushed from right to left, moves away from under the lug t and g¹
respectively.
The piece is leaf-shaped and has a slot in the shape of an obtuse angle
(Figure 11), and rivetted or otherwise fixed to it, is a detent, so that in this
position the cutting dies are prevented from rotating.
To the wheel P are fixed the cam x and the axle Z which is supplied with
the pins w, w¹, and w¹¹, or these parts and the wheel P may be formed in one solid
piece.
By means of the apparatus shown in Figure 12, which we do not claim as novel,
the wire is fed along in the hollow head-stock spindle.
On one slide rest is placed the shaping tool and on the other the tool for cutting
off the finished pieces.
The transfer shaft J is common to both slide-rests and the construction is

page_text: similar in both, but one part is without the cog wheel M, and the other without
the bevel wheel K.
The action in the cutting of a shaped piece or a screw is as follows:-
Suppose the chuck F is open; that is to say, the jaws bb are not pressed
together by the lever h, the wire, the nearer end of which has been turned
according to the desired length of the screw (exclusive of head), is, by means of
the feed, moved forwards until it strikes against the cutting dies in the spindle W.
At this moment the pin w¹¹ of the axle Z moves before the projection g¹, which is
screwed to the die spindle W and pushes the same a little forward, whereby at the
same time, the wire is pushed back to the exact length of screw to be made. Now
the respective sliding piece in the saddle is lifted, and offers resistance to the
lever h, which rotates with the chuck F, whereby the wire is firmly grasped in the
chuck. The sliding piece with the little pulley then goes back, and, by means of
the grooved cam, the slide rest with the shaping tool is moved against the wire.
While the wire is being turned off to the required thickness for the next screw,
the cutting apparatus is pressed firmly against the wire by means of the second
and longer pin w', so that the cutting apparatus grasps the rotating wire which
screws itself into the cutting apparatus; thus the thread is cut, and the head of the
screw, and also the length of the next screw turned, by means of the shaping tool
on the slide rest.
During the cutting of the thread, the cutting dies are pulled forward, and as the
lugt (and g respectively) does not leave the catch v, the latter still prevents the
rotation of the shaft and die spindle.
When the screw is cut the slide rest with the tool recedes.
In the meantime the pin w of the axle Z has entered the angular slot of the
catch v, induces a movement of the latter, and makes it pass away from under
the projection t (and g¹ respectively).
At the same time by means of the cam of the wheel P the parallel rod O is
pushed forwards, the projection of the cam pressing against the lug q.
Thereby the friction plate V is pushed into the loose pulley T and the die
spindle W rotates now at a considerably higher speed than the head-stock spindle A,
as the pulley T is connected by a belt with the power-shafting or direct to a
motor; thus the cut screw screws itself out of the cutting dies, and the spindle W is
then drawn back into its former position by the before mentioned springs.
The cam of the wheel P has now passed away from under the projection of the
parallel rod O, and this rod is also brought back into its former position by a
spring. Now the friction plate V sets the pulley T again free. The pin w having
left the slot of the catch the latter is again, by means of a spring (pushed
partly under and partly over the lug t) and the whole mechanism is in its former
position.
Now by a second groove the other slide rest with the cutting tool is pressed
against the wire and the finished piece (the screw in this case) detached from
the wire.
Then the whole process is repeated and so on.
The grooved cams, which induce the motion of the slide rest, are exchangeable,
thus the movements of the slide rest can be varied according to the grooves. The
projection g¹ screwed to the die spindle W is adjustable to regulate the length of
the screw threads.
The second head-stock B' B' is adjustable on the bed of the lathe and also
the wheel R through which the revolution of the wheel R¹ is transmitted to the
wheel R¹¹¹
Having now fully described the nature and objects of the invention communi.
cated to me by my correspondent be it known that what is claimed is :-
First. An automatic lathe consisting of: the hollow headstock spindle A in
combination with the eccentric and pawl D, the stepped pulley C, the chuck F,
the sliding rests G G, the die spindle W with the lug t and projection g¹, the loose
pulley T, the friction plate V, the parallel rod O, the catches u and v, the ratchet

page_text: wheel E, the shaft J, the bevel wheels K. K', and the gearing wheels M, R, R¹, R",
R, and P, the latter with the cam x and the axle Z which is supplied with the
pins www, substantially as described.
Second. In an automatic lathe :-
(a) the chuck F, consisting of a circular piece with a recess a, in combi-
nation with the moveable rim or half-ring r, the levers and the jaws b b.
(b) the slide rest consisting of the pieces f, G, and U, (Figure 6) the
axle Jin combination with the bevel wheel K, the grooved cam L, the gearing
wheel M, the cam pulleys QQ, the levers R, and pieces S, substantially as
described.
In witness whereof I, the said Frank Wirth; have hereunto set my hand and
seal this twenty first day of November in the year of our Lord One thousand
eight hundred and eighty three.
FRANK WIRTH
(L.S.)