IMPROVEMENTS IN SCREW-CUTTING MACHINERY
Year: 1878

page_text: LETTERS PATENT to Henry Emanuel Russell, of New Britain, Connecticut,
United States of America, now of 8, Southampton Buildings, London, for
the Invention of "IMPROVEMENTS IN SCREW-CUTTING MACHINERY."
Sealed the 19th July 1878, and dated the 15th May 1878.
PROVISIONAL SPECIFICATION left by the said Henry Emanuel Russell at the
Office of the Commissioners of Patents on the 15th May 1878.
HENRY EMANUEL RUSSELL, of New Britain, Connecticut, United States of
America, now of 8, Southampton Buildings, London. " IMPROVEMENTS IN SCREW-
CUTTING MACHINERY."
This Invention relates to screw-cutting machinery, and has especial reference to
the means by which a screw blank is held in the jaws of a screw-cutting machine,
so that it will not slip in the said jaws during the operation of cutting a thread
upon it.
The said improvements are particularly intended for use in that class of screw
machines which are used for making machine or fine threaded screws, and in which
is employed a die for cutting the thread instead of a chasing tool, although the
said improvements are applicable to any description of screw-cutting machine.
In screw-cutting machines which have a die for cutting the thread it is necessary
that the blank should be held in the jaws of the spindle with a very severe
gripe.
În machines heretofore used for this purpose the holding pressure has been
applied to opposite sides of the screw head, and to the shank directly under the
head in the line of the transverse axis. The result has been that many heads are
crushed, particularly those whose nicks happen to stand while held in a plane
parallel or approximately so with the plane of the faces of the jaws. Again, if the
metal of the blank is not of uniform density, or if the jaws do not exert an equal
degree of pressure, the axis of the blank is liable to be thrown out of line with the
Povice Gd1

page_text: axis of the cutting die. Moreover, the extreme pressure which is exerted upon the
blanks frequently causes adhesion of the same to one of the jaws after they open
to discharge a blank, thereby exposing the machine to injury when the feeding
fingers come into action to introduce the succeeding blank to the spindle.
The purpose of this Invention is to provide means for holding a screw blank in
the jaw spindle of a screw-cutting machine by pressure applied against the top
surface of the blank head in the direction of its longitudinal axis, in combination
with pressure applied mainly against the bevelled surface of the under side of the
head.
In practising, the said Invention I provide two levers somewhat similar to the
ordinary jaws for holding blanks. They are mounted in the spindle head upon
strong fulcrum pins, and work in recesses or slots. The rear ends of these levers
are connected by links of equal length, having a common hinge pivot in a sliding
central bar. This bar passes through a collar, and between the end of this collar
and the face of a nut on the end of the bar is arranged a coiled spring, the tension
of which can be increased by screwing up the nut, but whose tendency is always
to pull the said central bar in a direction which will bring the links more nearly in
a straight line, and consequently tend to set the rear ends of the said levers further
apart.
The front ends of the said levers are furnished with hook-shaped clamps of
hardened steel. These clamps hold the screw blank by the under side of the head
against a seat or socket, in which the top side of the blank head is seated. For
this purpose the inner edges of the clamps are so constructed as to form sections of
a hollow cone, or are otherwise shaped to conform to the bevelled or conical shape
of the under side of the head, and each embraces a portion of the usual conical
under portion of the head. This seat is set in a hollow cylinder or other suitable
guide to keep it centrally in the said spindle, and it is capable of a slight movement
longitudinally.
A spring may be applied in any convenient inanner to give it an impulse forward
when the seat is released from the force which has pressed it backward. This seat
serves a threefold purpose; that is to say, it forms one of the members of the clamp
to hold the screw blank; its concave or recessed face acts in combination with theso
'members to centralize the blank, and it serves by its movement forward under
the impulse of the said spring to eject the finished screw when the same is to be
"discharged from the spindle.
In a machine provided with this Invention a forward movement is given at the
proper times to the aforesaid bar by any suitable device. The effect will be that
the ends of the longer arms of the said levers will be brought nearer together, and
'the hooked clamps will open. The feeding mechanism now inserts a blank, so
that its head will bear against the seat, and. the said bar being thereupon moved
rearward by the action of the spring or by other suitable means, the jaws of the
holding clamps are moved toward each other, and engaging as above described
with the bevelled under portions of the head force the blank against the seat, and
carry it and the seat backward until the said seat comes to a solid bearing. The
blank is by this means firmly kept from slipping in the spindle by pressure applied
against the top surface of the head of the blank, in combination with pressure
applied in the opposite direction against the under side of the head.
In a modification of this Invention the seat is immovable, and the ejection of the
screw is effected by a pin, which occupies the axis of the seat and projects beyond
the face of the seat in consequence of the pressure of a spring. When a blank is
inserted into the spindle this pin is pushed backward, and bears with the full
pressure of the spring behind it against the blank's head.
When the holding clamps open to release the screw the said spring and pin act
'to throw out the screw.
In some instances the members or parts which are to bear against the under side
of the head may be arranged to move in a line transversely with the longitudinal

page_text: axis of the spindle, and the seat may be arranged to have a forward movement,
and in the line of the axis of the spindle.
The screw blank may be held by clamping pressure applied against the top and
under sides of the head, whether to effect such result one of the members of the
clamp is stationary and the other is movable, or whether both members have a
movement relatively to each other to permit the insertion of a blank and the
holding of it in the manner above described after it has been inserted.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Emanuel Russell in the Great Seal Patent Office on the 12th
November 1878.
HENRY EMANUEL RUSSELL, of New Britain, Connecticut, United States of
America, now of 8, Southampton Buildings, London. "IMPROVEMENTS IN SCREW-
CUTTING MACHINERY."
This Invention relates to screw-cutting machinery, and has especial reference to
an apparatus or device by which a screw blank is held in the jaws of a screw-cutting
machine so that it will not slip in the said jaws during the operation of cutting a
thread upon it.
The said improvements are particularly intended for use in that class of screw
machines which are used for making machine or fine-threaded screws, and in which
is employed a die for cutting the threads instead of a chasing tool, but the said im-
provements are applicable to any description of screw-cutting machinery.
In screw-cutting machines which have a die for cutting the thread it has been
necessary that the blank should be held in the jaws of the spindle with a very
severe grip.
In machines heretofore used for this purpose the holding pressure has been applied
to opposite sides of the screw head, and to the shank directly under the head in the
line of its transverse axis. The result has been that many heads are crushed, par-
ticularly those whose nicks happen to stand while held in a plane parallel or
approximately so with the plane of the faces of the jaws. And if the metal of the
blank is not of uniform density, or if the jaws do not exert an equal degree of
pressure, the axis of the blank is liable to be thrown out of line with the axis of the
cutting die. Moreover, the extreme pressure which is exerted upon the blauks
frequently causes adhesion of the same to one of the jaws after they open to dis-
charge a blank, thereby exposing the machine to injury when the feeding fingers
come into action to introduce the succeeding blank to the spindle.
The purpose of this Invention is to provide a clamp for holding a screw blank in
the jaw spindle of a screw-cutting machine by pressure applied against the top
surface of the blank head in the direction of its longitudinal axis in combination
with pressure applied mainly against the under side of the head.
In the accompanying Drawing,-
Figure 1 is a front view of the said apparatus shewing the jaws closed and holding

page_text: Figure 2 is an exterior view partly in longitudinal section, shewing the jaws in
the same position.
Figure 3 is an exterior view, with one of the jaws partially cut away to show the
discharger.
Figure 4 is a sectional side view shewing the said jaws opened to receive a
blank.
Figure 5 illustrates a modification of the said apparatus, herein-after described.
Like letters indicate corresponding parts throughout the Drawing.
A, A, are two levers somewhat similar to the ordinary jaws for holding screw
blanks. They are mounted in the spindle head upon strong fulcrum pins a, and
work in suitably-shaped recesses or slote. The rear ends of these levers are con-
nected by links b, b, of equal length, having a common hinge or pivot c in a sliding
central bar B. This bar passes through a collar d, and between the end of this
collar and the face of a nut e on the end of the bar is arranged a coiled spring C,
the tension of which can be increased by screwing up the nut e, but whose tendency
is always to pull the said central bar B in a direction which will bring the links b, b,
more nearly in a straight line, and consequently tend to increase the distance
between the rear ends of the levers A, A.
The front ends of the levers A, A, are furnished with clamp jaws f,f, of hardened
steel. These jaws are designed to hold the screw blank by the under side of the
head against a seat bearing or socket, in or against which the top side of the blank
head rests when the same is held in the said jaws. For this purpose the inner edges
of the jaws are shaped or formed to conform to the shape of the under side of the
screw head whether the same is conical or otherwise, and each jaw embraces a
portion (preferably slightly less than one-half) of the under portion of the screw
head.
In Figure 2 I have shewn a seat or bearing / properly shaped to receive the top
of the screw head. In this instance it is shown concave to accommodate a "round
headed screw. This seat is set in a hollow cylinder or chamber i or other suitable
guide to keep it centrally in the said spindle, and it is capable of a slight movement
longitudinally. This cylinder is formed or fixed on the cross bar which is secured
to the front of the apparatus by screws i².
A spring k may be applied in any convenient manner to give the seat h
a forward impulse when this seat is released from the force which has
pressed it backward. This seat serves a three-fold purpose; that is to say,
it forms one of the parts or members of the aforesaid clamp to hold the screw
blank; the face acts in combination with the parts or members f.f, of the said
clamp to centralize the blank, and it serves by its movement forward, under the
impulse of the spring k, to eject the finished screw when the same is to be discharged
from the said apparatus. But if desired this spring may be dispensed with, the
screw blanks then simply falling out of the clamp when the jaws are opened.
In a machine provided with this Invention a forward movement is given at the
proper times to the aforesaid bar B by any suitable device. The effect of this move-
ment will be that the ends of the longer arms of the said levers A, A, will be brought
nearer together and the hooked jaws f.f, will open as shown in Figure 4. The
feeding mechanism with which the said machine is provided now inserts a blank
so that its head will bear against the seat h, and the bar B being thereupon
moved rearward by the action of the spring C or by other suitable means, the jaws
ff of the said clamp are moved toward each other and engaging as above described
with the under portions of the head, force the blank against the seat h and carry it
and the seat backward until the said seat comes to a solid bearing. The blank is
by these means firmly kept from slipping in the spindle by pressure applied
against the top surface of the head of the blank, in combination with pressure
applied in the opposite direction against the under side of the head.
The advantages of this method of holding a blank in the spindle of a screw
machine are that the head is not crushed and the nick is left uninjured. The form
of the seat in connection with pressure applied in this manner tends to centralize
the blank, and by reason of the great extent of frictional holding surface such

page_text: extreme pressure is not necessary as would be required if the blank were held in
griping jaws as heretofore constructed; therefore there will be no sticking of the
screws in this improved clamp when the same opens to release or discharge them.
When the jaws f. f, are opened the spring seat h throws the screw outward in a
well understood manner.
In Figure 5 I have shewn a modification of this discharging or ejecting device.
In this instance the seat h is immovably fixed or formed on the cross bar i, and the
ejection of the screw is effected by the pin m which occupies the axis of the seat
and is caused to project beyond the face of the seat by the pressure of the spring k.
When a blank is inserted into the spindle this pin is pushed backward and bears
with the full pressure of the spring behind it against the blank head.
When the holding jaws open to release the screw the said spring and pin act to
throw out the screw in a well understood manner.
Having thus fully described my said Invention and the manner of performing the
same, I wish it understood that although I have shown and described a spindle in
which the hook-faced jaws move in the arc of a circle and carry the blank in so
moving against a seat, it is evident that the construction and arrangement of the
parts or members which co-operate to form the clamp for holding the blank by
pressure applied against the top and the under sides of the head may be greatly
varied; for instance, the parts or members which bear against the under side of the
head may be arranged to move in a line transversely to the longitudinal axis of the
spindle, and the seat may be arranged to have a forward movement and in the line
of the axis of the spindle; furthermore the screw blank may be held by clamping
pressure applied against the top and under sides of the head, whether one of the
members of the clamp is stationary and the other is movable, or whether both mem-
bers have a movement relatively to each other to permit the insertion of a blank
and the holding of it in the manner above described after it has been inserted; and
I further wish it understood that I claim,-
First. The method of holding a screw blank in the spindle of a screw-cutting
machine during the operation of cutting the thread on the blank, which method
consists essentially in the employment of a clamp so applied to the head of the
blank as to exert pressure upon the top and under sides of the head in the manner
above specified.
Second. The combination of a seat for the head of the blank to abut against,
with clamping devices co-operating therewith to exert pressure against the under
side of the screw blank as above specified.
Third. The combination of a seat having a concave or recessed face with the
cylinder or chamber, and with clamping devices arranged to press against the under
side of the head of the blank whose head has been placed against such seat, whereby
the blank is adjusted centrally in the spindle as above set forth.
Fourth. The combination with the aforesaid apparatus or device for clamping the
head of a screw blank of a spring ejector for discharging the screw from the spindle
after the jaws are opened as above specified.
In witness whereof, I, the said Henry Emanuel Russell, have hereunto set
my hand and seal, this Fourth day of June, in the year of our Lord One