IMPROVEMENTS IN MACHINERY FOR THE MANUFACTURE OF SCREWS
Year: 1883

page_text: LETTERS PATENT to Henry Harris Lake of the firm of Haseltine Lake
"
"
Com-
and Co Patent Agents Southampton Buildings London for an Invention of
IMPROVEMENTS IN MACHINERY FOR THE MANUFACTURE OF SCREWS
municated to him from abroad by the Harvey Screw Co, (Incorporated)
of Jersey City, New Jersey, United States of America
PROVISIONAL SPECIFICATION left by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 12th February 1883.
"
HENRY HARRIS LAKE of the firm of Haseltine, Lake, and Co, Patent Agents,
Southampton Buildings, London, IMPROVEMENTS IN MACHINERY FOR THE
MANUFACTURE OF SCREWS," [A communication to him from abroad by the
Harvey Screw Co, (Incorporated) of Jersey City, New Jersey, United States of
America]
This Invention relates to machines for rolling the threads of screws, in contra-
distinction to cutting the same, and is chiefly designed to improve the machinery
described in the Specification of Letters Patent dated A.D. 1881 No. 4,445, parts
of the present Invention being applicable to other machines for rolling screw
threads, and for other purposes.
In the machinery to which the said former patent relates the thread of the
screw is formed by the combined action of a curved stationary die, and a cylindrical
rotating die upon a blank introduced between the dias, and rolled along the face of
the stationary die by the friction of the rotating die. The two dies have. their
adjacent or working faces formed with parallel ridges at the proper angle of
inclination with the plane of motion of the rotating die operating upon the blank,
so that as it passes between the two dies the ridges on the faces of the dies will
impress the body of the blank, and raise a spiral rib thereon, the said spiral rib
forming the thread of the screw.
Heretofore, in this class of machines, the faces of the two dies have been
substantially equidistant from each other from top to bottom, that is at right

page_text: "
"
that
angles across their face so that the thread produced would be of equal diameter
throughout and thus make what is commonly called a blunt-pointed screw
is to say, the thread will terminate on the cylindrical body of the blank.
The object of the present Invention is principally to adapt this class of machines
" that is to
to the making of what are commonly called "gimlet pointed screws
say a pointed screw in which the spiral rib which forms the thread is continued
from the body down onto the point, so that the point of the screw will present the
appearance of the point of the instrument commonly called a "gimlet," the similarity
of the two points giving to the screw the name "gimlet-point" and which, because
of such gimlet-like point, readily enters the wood without necessarily boring a hole
in advance for the introduction of the screw.
According to this Invention.I shape the adjacent or working faces of the dies to
correspond in transverse section to the longitudinal or axial section of the screw to
be produced, that is to say the working faces of the dies are constructed to approach
each other on that portion where the point of the screw is formed, and I continue
the inclined ribs on the faces of the dies over these inwardly extended or approaching
surfaces, whereby the spiral rib on the blank will be continued to the point; other
-details of construction comprised in the said Invention are more particularly herein-
after pointed out.
In describing this Invention reference is made to the machine described in tho
Specification of the former patent hereinbefore referred to, that is, a machine
which employs three curved stationary dies and three corresponding rotating
cylindrical dies, the adjacent surfaces of the several dies provided with the inclined
ridges so as to gradually operate upon the blank to produce the thread, the first
partially forming the thread, the second porforming additional work, and the third
completing the thread. In practice it is found advantageous to cause the first and
last of the series of dies to perform the threading of the point; to this end the
face of the stationary curved die near its lower edge is gradually drawn inward
from the point where the blank enters, to the point of its exit, and the revolving
die has the lower part of its working face correspondingly and gradually increased
in diameter from the point where the blank is first taken, so that the reduction of
the point, and the formation of the rib thereon, are gradually effected as the blank
is rolled between the two dies.
Passing from the first pair of dies into the second pair, the thread on the body
of the screw that is above the point is further advanced, but without action upon
the pointed portion thence passing to the third pair of dies, which are also
constructed with their lower edges gradually approaching each other, and with the
inclined ribs continued as in the first pair of dies so as to complete the point and
deliver the screw finished.
While this class of machines by which the thread is formed step by step is
preferred, the whole work of forming the thread on the screw and continuing it
onto the point may be produced by a single pair of dies: again while the stationary
curved die and the revolving cylindrical die are preferable, the work may be dono
on dies having straight parallel surfaces, the blank rolled between the two, and
one of such dies may be stationary and the other movable, or both may be movable,
that is both may have reciprocating motion imparted to them to cause their
surface to roll the blank along between them.; this part of the Invention is
therefore not to be understood as limited to any particular construction or arrange-
ment of dies, it only being essential that the adjacent or working faces of the dies
between which the blank is rolled shall approach each other at that edge where
the point is formed, and the inclined ridges on the faces of the dies continued onto
these projecting surfaces, so as to continue the spiral rib of the body down onto
the point of the blank.
A second feature of this Invention which relates particularly to the employment
of two or more revolving cylindrical dies, with corresponding stationary curved
dies, consists in making the dies adjustable with relation to each other, that is to
say, in order to make a free delivery from one pair of dies to the next, and avoid

page_text: mechanism for making the transfer as in the said former machine, the dies are set
with relation to each other so that the blank passes from between the first directly
into the space between the second, and so from the second into the third.
As it would be difficult to construct the machine with the dies rigidly fixed in
their relative position to each other, so that the space between one pair of dies
and the next would be of precisely the diameter of the blanks, the bearings which
support the movable dies are made adjustable in the frame of the machine by
means of set-screws, so that the dies may be moved toward or from each other, as
occasion requires. The fixed dies are also made adjustable on the frame of the
machine whereby they may be adjusted to conform to the revolving dies. This
adjustment of the dies with relation to each other constitutes the second part of
this Invention.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Harris Lake in the Great Seal Patent Office on the 11th August
1883.
HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co Patent Agents
Southampton Buildings, London, "IMPROVEMENTS IN MACHINERY FOR THE
MANUFACTURE OF SCREWS a communication to me from abroad by the Harvey
Screw Company (Incorporated) of Jersey City, New Jersey, United States of
America
"
This invention relates to machinery for forming the threads of screws, by the
combined action of a curved stationary die and a cylindrical rotating die, upon a
blank introduced between the said dies and rolled along the face of the stationary
dio by the friction of the rotating die which machinery is an improvement upon
that described in the specification of former Letters Patent dated October 12th
AD. 1881 No 4445.
The machinery described in the said former specification consisted principally in 1
the combination of two or more pairs of dies, the first of the said pairs of dies being
arranged to form a comparatively shallow groove in the path of the thread around
the shank of the blank and the next pair of dies being arranged to make the said
groove deeper, either to the extent of finishing the thread, or partially finishing it.
preparatory to subjecting the blank to the action of a third pair of dies, and so on
until a thread of the desired depth is formed; also the faces of the dies were
vertically parallel to each other, so that the thread would be formed on the blank
of an equal diameter throughout, and thus, so far as the operation of the dies were-
concerned, would only produce a blunt-pointed screw.
The object of the present invention is principally to adapt the rolling operation
of forming the thread, to the making of "gimlet-pointed" screws, that is to say,
screws in which the end of the body is reduced or drawn into a pointed shape, and
the spiral rib which forms the thread is continued from the body down around
this contracted or conical shaped point, producing a point substantially like that of
a "gimlet" and from which such a screw takes its name.
The said invention comprises dies between which the blank is rolled, the faces
of the said dies having parallel ridges formed thereon at the proper angle of
inclination with the plane of their motion and being equidistant from each other
from the upper side of one to near the lower side of the other, the lower portion
of the said faces being inclined toward, or gradually approaching, each other, the
said gradually approaching or inclined portion having ridges formed thereon,
which will impress upon the pointed portion of the blank in a similar manner to
the ridges of the parallel portion of the dies on the body, and thereby continue
the spiral rib from the body down onto the reduced or conical pointed part of the
blank thereby producing a gimlet-pointed screw, the said invention also comprises
the combination with the said dies of improved feeding mechanism whereby blanks
are delivered to the rolling dies at a positively predetermined time as more fully
hereinafter described.
In the accompanying drawing
Figure 1 is a top view or plan of the rotating and stationary dies in their proper
relation to each other.
Figures 2, 3 and 4 are transverse sections through the working faces of the
dies.
Figure 5 is an under-side view of the rotating die, showing the segments for
forming the gimlet-point.

page_text: Figure 6 is a front view of the rotating die, illustrating the method of adjusting
the segment,
Figure 7 is an end view of the segment.
Figure 8 shows a pointed blank.
.
Figure 9 is a partial plan drawn to a reduced scale of the frame, illustrating the
method of adjusting the rotating dies with relation to each other.
Figure 10 is a section through the dies, showing the radial adjustment of the
Begments.
Figures 11, 12, and 13 are detached views illustrating the feeding devices.
The best form of machine for producing gimlet-pointed screws by this method
of rolling, has three cylindrical rotating dies, and three correspondingly curved
stationary dies.
In the drawing A indicates the first cylindrical rotating die and A¹ its curved
stationary die, B the second rotating cylindrical die and B' its curved stationary
die, and C the third cylindrical die and C' its curved stationary die. The depth
of these dies corresponds substantially to the length of the threaded portion of
the longest blank to be threaded therein. A side view of one of these dies,
say A, is shown detached in Figure 6. The rotating and stationary dies are each
formed with parallel ridges of metal upon the faces at the proper angle of incli-
nation with the plane of motion of the rolling dies, as in the said former
specification the ridges of the first pair forming a comparatively shallow spiral
groove in the blank, the ridges of the next pair deepening that groove, and the
ridges of the third pair completing the groove, which raises and forms the spiral
rib or thread on the blank as in the said former specification. Instead of making
the surfaces of the pair of dies vertically parallel, the space between the dies of one
or more pairs is contracted at the bottom or lower portion, as seen in Figures 2
and 4 which represent vertical sections through the first and third pair of dies;
this contraction should be gradual until at an advanced point the surfaces of this
part of the two dies come substantially together.
This contraction is best made by introducing into both the rotating and
stationary die the segments a and a' Figure 2. These segments occupy an extent
equal to about one fourth of the circumference of the rotating dies.
A recess b is cut in the under surface of the dies and the segment a, made to fit
that space, but preferably the recess in the die is slightly deeper than the thickness
of the segment; the outer surface of this segment as seen in Figure 5, is excentric
to the surface of the die itself, so that starting substantially flush with the surface
of the die as at d, Figure 5, it gradually increases its projection until at the
opposite end e it reaches substantially half way across the space between the dies.
The working surface of this segment is inclined from its upper edge downward,
as seen in Figure 7, the inclination being gradual from the starting point d to the
end e.
This working surface of the segment or pointing portion of the die is
provided with ridges inclined at the proper angle, and operating as a continuation
of the inclined ridges on the upper portion of the dies. The segment is adjusted in
its recess so that the ridges on the segments as they commence their operation upon
the blank continue the formation of the spiral rib from the body down to the
point, and thereby produce the "gimlet pointed" shape. This adjustment of the
segments is best made by means of set-screws e' through a disc f fixed to the under
side of the die, the said set-screws bearing against the under side of the segments,
the surplus space above the die being filled with thin strips of metal, paper, or
other suitable material, so that by the introduction or removal of such strips and
the adjustment of the set-screws e¹ the segments may be adjusted into their proper
relation to the die. This adjustment of the segments adapts the dies to rolling
different lengths of screws that is to say, for a longer screw the segment will be
lowered, and for a shorter screw it will be raised.
The curved stationary dies are provided with corresponding segments, as seen in
broken lines Figure 1. The extreme inclination of the surface of the segments.

page_text: corresponds to the pointed portion of the screw to be formed by them, or the
operation to be performed upon the blank.
The rotating dies are adjusted or arranged with relation to the circular die as
seen in Figure 1, so that the starting point d of the segment on the rotating die
will coincide with the starting point d' of the segment in the curved die, and so
that the blank h (see Figure 1) introduced at the proper time will be received by
the said segments at their starting point or at the point where they are substantially
flush with the surface of their respective dies. The revolution of the rotating dio
being in the direction indicated by the arrow, the blank h, will be rolled along the
surface of the dies, as described in the said former specification, and during this
rolling operation the pointed end will be gradually operated upon by the inclined
surfaces of the segments, and drawn into a pointed shape with the spiral groove
continued to the point, as seen in Figure 2.
It is found advantageous to omit any operation upon the pointed portion of the
blank in its passage between the second pair of dies, and to complete it in the
third pair, and thus the operation is represented in the drawing. The third pair
of dies CC, are each provided with segments c c¹, corresponding with the
segments a, a¹ of the first pair of dies, and in substantially the same relation to
each other, differing only in the fact that the ridges in their faces are of sufficient
depth and sharpness to finish the point, as seen in Figure 4.
It is desirable and economical to first point the blanks, as seen in Figure 8,
because it causes less strain upon the dies as well as upon the metal of the blank,
that is when the entire drawing, reducing or pointing is performed by the dies
themselves, yet the end of a cylindrical blank introduced. between the dies as before
described, and rolled through the same, will be reduced, shaped, and threaded, us
hereinafter described.
Two segments are illustrated in the rotating dię by which it will be understood
that but two blanks will be operated upon in a full revolution of the rotating die,
but a greater or less number of segments may be introduced.
By suitable adjustment between the respective pairs of dies the blank being
rolled between one pair readily passes from the space between one pair into the
space between the next without the intervention of the mechanism employed
according to the said former specification, but to do this it is necessary that one
rotating die shall stand so near the next that the spiral groove formed by the first
pair of dies will be engaged by the corresponding rib on the next rotating die. To
facilitate this adjustment of the rotating dies with relation to each other, the
shaft a² of the first die, and the shaft c² of the third die are arranged in bearings D,
which bearings are fitted in a recess in the frame, slightly greater in extent than
the diameter or width of the bearing, so that the said bearings may have a certain
amount of play or movement toward or from the centre shaft 62 as seen in 4
Figures 9 and 10; through the frame from each extreme and toward the respective
bearings D, the set screws are introduced, which bear the one against one
bearing, and the other from the opposite direction against the other bearing; these
screws tend to force the said bearings and the shafts which they carry toward the
centre shaft; thus by turning the screws in one direction the extreme rotating 4
dies will be forced respectively toward the central rotating die, or vice-versa, as
occasion may require, until the proper adjustment or relation of the respective dies
is attained
On the side of the bearings opposite the screws thin strips of metal are introduced
against which the bearings will be forced, or set-screws may be introduced from 5
that side if preferred.
To make a nice adjustment of the working surface of the segments with relation
to the general surface of the die in which they are set, the back of the segment is
made inclined from the top downward and inward, and from the upper side of the
die near each end of the segments an adjustable screw a³ is introduced, its lower 5
end extending down in rear of the inclined back of the die, as seen in Figure 10,

page_text: the lower end of the screw being tapered to correspond with the incline on the
back of the die, hence by forcing either of the set-screws a³ downward, its inclined
end will bear against the inclined surface of the die, and acting like a wedge will
force that end of the die outward to make its projection beyond the surface of the
body of the die greater. To reduce this projection the screw must be withdrawn
and the segment pressed inward.
Instead of using the set-screw, a key and wedge may be employed. This
adjustment greatly facilitates the proper setting of the segment, as by it either
end may be readily adjusted without affecting the other end. Instead of making
the back of the die inclined throughout, the segments may be constructed with
seats corresponding with the tapered end of the screw.
Although the machine is described as having two pairs of the series of dies for
forming the gimlet point, the first and third, the invention is not to be understood
as limited to such an arrangement, as the gimlet point may be formed entirely in
one pair of the series, say the first or last.
In this class of screw-threading machines it is desirable that an automatic feed
shall be provided, and such a feed must be positive in its action in order to
introduce the blank at a certain predetermined time. To this end a feed is
produced, illustrated in Figures 11 and 12. The usual feed channel E is employed,
which is supplied by the well known "Sloane" or other device which will deliver
the blanks to the channel with their head uppermost, and so that through the said
channel the blanks will be guided to the proper point. Across this channel at its
end is a cut-off m, which consists of a bar properly guided, its outer end being
connected with a lever F hung upon a fulcrum G below, and provided with a
suitable spring H, the tendency of which is to draw the said lever inward and hold
the cut-off m, across the channel as seen in Figure 11.
From the shaft a² or from any other part of the machine, a vibratory movement
is imparted to the lever F, here represented as effected by a cam I on the shaft a²,
operating outward against the lever F so as to withdraw the cut-off m, as indicated
in broken lines Figures 11 and 12 as this cut-off is withdrawn from the foot of
the column of blanks the lowest blank will be thrown down by the weight of the
blanks behind it, until it comes into a position forward of the cut-off, and against
a pusher n, as seen in Figure 13, this pusher n, stands in line with a transverse
continuation o of the channel E, the said transverse channel o leading directly into
the space between the stationary die A' and its rotating die A as seen in Figure 11.
The pusher n has a reciprocating movement imparted to it by means of a cam L
on the shaft a, through a lever M, or otherwise. At the proper time the pusher n
is withdrawn from the foot of the channel E, as seen in Figure 11, at the same
time the cut-off euters between the blank which stood against the pusher and the
next in the column, so as to cut off that column; and the blank so delivered stands
in the channel forward of the pusher as seen in Figure 11, when next the pusher
advances as seen in broken lines Figure 11, it pushes the blank forward through
the channel o, into the proper position, and at the proper time to be taken by 'the
rotating die and carried along between it and the stationary die.
In order that the blank may be forced in front of the pusher, the forward end
of the cut-off is inclined as shewn, so that as it enters in rear of the first blank it
will force that first blank down in front of the pusher, and in order that the
pusher may ensure the delivery of the blank into the space between the two
dies A. A¹ its forward end is inclined as shewn so as to bear upon the blank, and
by its wedge shape tend to force it forward and into the said space between the
dies.
The pusher lever, like the lever F, is provided with a spring P, the tendency of
which is to draw the pusher outward to receive the blank.
By this simple arrangement the blank is positively delivered without danger of
interruption in the feed, or of introducing the blank out of line, the movement
of the pusher to deliver the blank being positive.
Having thus fully described the said invention as communicated to me by my

page_text: foreign correspondents and the manner of performing the same I wish it understood
that I claim.
First. A rotating cylindrical die, and a stationary curved die for forming the
threads of screws, in which dies the working faces for impressing the thread upon
the body of the blank present parallel ridges at the proper angle of inclination
with the plane of motion of the rotating die, the lower portion of the said faces
being inclined toward, or gradually approaching, each other, and the said inclined
portion of the faces being provided with properly inclined ridges whereby the rib
formed on the blank will be continued from the body of the blank down to the
pointed or contracted portion thereof, substantially as described and for the purposes
specified.
Second. A rotating cylindrical die and a stationary curved die for forming the
threads of screws, in which dies the working faces present parallel ridges at the
proper angle of inclination with the plane of motion of the rotating die, a segment
arranged in the lower portion of both the rotating and the stationary dies, the
said segment presenting a face excentric to the working face of the said dies, and
inclined to the vertical plane of the said face of the dies, the said segments
gradually approaching-each other, and the said inclined portion of the faces being
provided with properly inclined ridges whereby the rib formed on the blank will
be continued from the body of the blank down to the pointed or contracted portion
thereof, substantially as described and for the purposes specified.
Third. A rotating cylindrical die and a stationary curved die for forming the
threads of screws, in which dies the working faces present parallel ridges at the
proper angle of -inclination with the plane of motion of the rotating die, a segment
arranged in a recess in the lower part of each of the said dies, the said recess being
of greater depth than the thickness of the segment, the face of the said segudents
gradually approaching each other, and having upon their faces properly inclined
ridges, whereby the rib formed on the body of the blank will be continued there-
from down to the pointed or contracted portion of the blank, and the said segments
being made adjustable radially in the said recesses, substantially as described and
for the purposes specified.
Fourth. In a machine for rolling screw threads, two or more pairs of dies, each
pair consisting of a rotating die and a stationary curved die, the respective pairs of
dies having the ridges on their working faces at the proper angle of inclination
with the plane of motion of the rolling die, one of the said rotating dies being
made adjustable with relation to the next, substantially as described and for the
purposes specified.
Fifth. The combination of a rotating cylindrical die, and a corresponding
stationary die, baving upon their working faces parallel ridges at the proper
angle of inclination with the plane of motion of the rolling die, a feed channel E,
a transverse continuation o of the said channel leading to the space between the
dies, a cut-off m, and a pusher n, with mechanism substantially as described for
imparting movement to the said cut-off and pusher, the said pusher being inclined
upon its working face substantially as described and for the purposes specified.
In Witness whereof I the said Henry Harris Lake have hereunto set my hand
and seal this Tenth day of August in the year of our Lord One thousand eight
hundred and eighty three