IM- PROVEMENTS IN MACHINERY FOR MANUFACTURING SCREWS
Year: 1876

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, for the Invention of "IM-
PROVEMENTS IN MACHINERY FOR MANUFACTURING SCREWS." A communication
from abroad by the American Screw Company (Incorporated), of Providence,
Rhode Island United States of America.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 18th December 1876.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN MACHINERY FOR MANU-
FACTURING SCREWS." A communication from abroad by the American Screw
Company (Incorporated), of Providence, Rhode Island, United States of America.
My improvements are applicable to machines for manufacturing either wood
screws or fine-thread screws, but are especially useful in connection with machines
for finishing fine-thread screws in which the threads are cut by dies.
In machines of this class, which are sometimes called die threaders, it is necessary
that the jaws shall gripe the screw blank with excessive force, to prevent the
turning of the blank in the jaws under the action of the dies upon its shank. It
results from this excessive gripe that the finished screw sometimes sticks in one of
the jaws when they are opened and will not fall therefrom by its own gravity. It
thus becomes necessary to provide positive means for dislodging the screw from the
jaw. This has heretofore been accomplished by a stationary plate or plates in front
of the jaws, such plates having been so arranged as to bisect the path swept by a
blank adhering to either of the jaws when the jaws open. Such stationary plates
however are necessarily placed at a considerable distance aside from the position
occupied by the blank when the jaws are closed, in order to be out of the way of
the dies which in cutting the thread approach close to the front of the jaws.

page_text: My Invention comprises a movable discharger or striker which at the proper
time sweeps across the front of the open jaws, and then immediately retires to its
normal position behind a shield.
In its forward motion my striker serves to knock out a screw which may be
sticking in either of the open jaws and then returns to a position where it is
entirely out of the way of the dies.
In fine-thread machines it is customary to lubricate the blank with oil; this is
usually effected by a jet of oil directed upon the blank immediately in front of the
dies. By the revolution of the dies, or of the blanks, or of both, as the case may
be, the oil is thrown off by centrifugal force and carries with it chips or cuttings.
My shield prevents this oil and the chips from reaching the striker and adhering
to it. Oily chips adhering to the striker while at rest would be thrown from the
striker in the direction of the jaws by the shock of the sudden movement which
the striker makes, and would be liable to be thrown into and adhere to the inside
of the jaws, in which position they would prevent the jaws from taking a proper
gripe of the next screw, or might indeed cause the breaking of the jaws.
For the successful use of the striker therefore it is required that its place of rest
shall be beyond the range of motion of the flying oil and chips, or that it shall be
protected by a shield which intercepts such oil and chips. My Invention includes
therefore as one of its elements a shield organized in relation to the striker and
the other parts of the machine, in the manner and for the purpose described.
The accompanying Drawing illustrates the said Invention.
Figure 1 is a front clevation of that portion of a fine-thread machine with which
my Invention is immediately connected, showing the front of the jaws and the
jaw stock, the upright portion of the frame of the inachine which supports the jaw
stock showing my striker, together with the mechanism which actuates it and the
shield which protects it, a portion of the latter being cut away to more clearly
exhibit the parts behind it.
Figure 2 is a similar elevation, showing the position assumed by the parts_when
the jaws after having been fully opened have commenced to close. In this Figure
the front part of the arun e is represented as cut away for the purpose of exhibiting
the interior of the chamber in which the bolt latch slides.
Figure 3 is a side elevation of the jaw stock and of the uprights in which it is
supported, affording a side view of the striker and of the mechanism which operates
it, and also of the shield, a portion of the latter being broken away as before to
exhibit more clearly the parts behind it.
Figure 4 is a longitudinal horizontal section through the line, x, on Figure 3,
showing the toggle joint for working the jaws.
The Drawing illustrates my Invention applied to a fine threader in which the
jaws do not revolve, but open and close in a horizontal plane. In this machine the
screw blank is griped in stationary jaws and a revolving die cuts the thread upon
its shank. The die and the feeding mechanism are not shown in the Drawings as
they have nothing to do with my Invention, which relates solely to the discharge
of the finished screw froin the jaws. In this case the motion to operate my striker
is borrowed from one of the jaws.
The Drawing exhibits a portion of the bed plate A of a fine threader and the
uprights a and a which support the jaw stock in which the swinging jaws c and c¹
are pivoted. The jaw c in its opening movement pushes against the end of the
lower arm of a rocking elbow which is provided with a friction roller d³, and is
maintained against the outer edge of the jaw c by the spring d. The upper arm e
of the rocker is furnished with a bolt latch held outward by a spiral spring f¹ and
pushed upward against the upper side of the chamber which contains it by the
flat spring The upper part of the beveled edge f³ of the bolt latch forms a
shoulder which engages the end of the arm e. This shoulder prevents the bolt
from yielding inwardly, except when a downward pressure is exerted upon the
beveled edge f³ of the bolt latch, as is the case when the arm e moves upward

page_text: after the striker has completed its motion and returned to its normal position, as
will presently be described. The striker G is a thin metal plate swinging upon the
pivot g and provided with a shoulder for engaging the end of the bolt latch f
The spring gholds the striker in its normal position, as shown in Figures 1 and 2,
but yields to allow the striker to swing across the front of the jaws in obedience to
the action of the bolt latch fupon the shoulder g² when the rocker & is actuated by
the opening of the jaw c. A thin metallic plate his secured to the frame, and
projects across the front of the rocker and of the striker when the latter is in its
normal position, and thus operates as a shield and intercepts any flying oil or chips
and prevents them from adhering to the surface of the striker. In the Drawing
this shield is represented as partially broken away, for the purpose of exhibiting
the parts behind it.
The operation of my Invention is as follows:-When the jaws open, after the
dies have finished their work in cutting the thread, the jaw c pushes back the lower
arm of the rocker and the bolt latch acting upon the shoulder g² causes the striker
to swing across the front of the jaws, and thus knock out a blank which may be
sticking in either jaw. In its downward movement the bolt latch fultimately
slides off the edge of the shoulder g², as shown in Figure 2, when the striker is
immediately forced back to its normal position by the action of the spring g³. The
striker is thus brought back to its normal position while the jaws are still open.
When the next blank is presented to the jaws by the feeding mechanism the jaws
close upon it, and the rocker being relieved from the thrust of the jaw c assumes
its normal position in obedience to the action of the spring d. In its upward
movement the beveled edge f³ of the bolt latch f strikes against the end or
poriphery of the shoulder g³, and is thus forced downward and backward into the
hollow arm e. When the lower edge of the bolt latch has risen above the shoulder g³
the bolt latch darts out in obedience to the action of the spring f, and is then in
position to again act upon the shoulder g² and impart a swinging motion to the
striker when the jaws again open. It will be seen that the direction in which
the edge of the striker moves is that which is most favorable for the dislodgement
of a screw sticking in either jaw; that is, that the plane in which the jaws open
and close constitutes the chord of the arc swept by the edge of the striker.
In a fine threader having stationary jaws like those shown it is convenient to
borrow the motion of the striker from the jaws. As such machines work very
rapidly the discharging mechanism must perform its operation very quickly, and by
borrowing the motion from the jaws themselves, as shown, the mechanism for
actuating the striker may be more readily adjusted with reference to the time in
which it acts.
In applying my Invention to a machine having revolving jaws it may be necessary
to provide the striker with a positive motion. In such a machine the shield will be
equally important as a means of protecting the striker from becoming coated with
oil and chips.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,―
First. A striker as described having a reciprocating motion across the front of
the jaws in combination with a shield, behind which the striker rests during tho
time when it is not in operation.
Secondly. In a machine for manufacturing screws provided with stationary jaws
for griping a screw blank, the jaw c and the elbow rocker having the arms & and e,
the latter provided with a spring-bolt latch fin combination with a swinging
striker G provided with a shoulder gå for engaging the lower edge of the bolt
latch f, as and for the purposes described.
Thirdly. The bolt latch f in the rocking arm e and the swinging striker G
provided with a shoulder g² in combination with a spring g³, as and for the purposes
set forth.

page_text: Fourthly. The bolt latch f contained in the hollow arm e and provided with the
shoulder in combination with the spring f, as and for the purposes set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Eighteenth day of December, in the year of our Lord
One thousand eight hundred and seventy-six.
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