Improvements in Machines for the Manufacture of Screws.
Year: 1887

page_text: Improvements in Machines for the Manufacture of Screws.
I, JOHN HASKINS LADD, of 116 Queen Victoria Street, in the County of Middlesex,
Manufacturer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement:
This invention relates to the class of machines for forming the screw-threads of
screws or bolts, in which the blank is rolled between two flat dies, the working surfaces
of which are provided with series of parallel ribs inclined in relatively opposite
directions.
The chief feature of the said invention consists in the provision of means for giving
to one of these dies, which I will hereinafter term the quick-moving die, several to-
and-fro endwise movements while the other die which I will hereinafter term the slow-
moving die, is making a single endwise movement. Another feature of the said
invention is the provision of means for gradually narrowing the space between the
two dies while they are thus moved. By these means the screw-thread is impressed
upon the body of a screw-blank during a prescribed number of forward and backward
movements of the quick-moving die, the blank being fed into the space between the
dies at one end of the slow-moving die, then rolled back and forth a prescribed number
of times along the working surface of the slow-moving die, and finally discharged,
after the screw-thread is formed, from the end of the slow-moving die opposite that
to which it was fed.
The said invention, moreover, comprises certain improvements in the construction of
the machine, and in the mechanism for feeding in the screw-blanks.
In the accompanying drawings, I have shown a machine constructed according to
my present improvements.
Figure 1 is a plan or top view of the said machine, showing the dies in the positions
which they occupy when about to commence the rolling operation.

page_text: Figure 2 is a longitudinal vertical section on the line æ, a, Figure 1:
Figure 3 is a transverse vertical section on the line y, y, Figure 1.
Figure 4 is a side view of the cams hereinafter referred to.
Figure 5 is a plan or top view of the dies, illustrating their relative positions when
in the act of seizing a blank at the commencement of the rolling operation.
Figure 6 is a transverse vertical section on the line,, Figure 5, the feed-ways or
chute and the blank which has just been seized by the dies being shown in elevation.
Figure 7 is a plan or top view of the portion of the machine in which the dies are
supported, showing the dies in the positions which they occupy at the termination of
the rolling operation, and
Figure 8 is a vertical section on the line, o, Figure 7.
The machine illustrated in the drawings has a substantial horizontal frame A, provided
with legs or standards at its corners, whereby it is supported upon, and secured to, a
suitable bench or base.
.
The driving shaft B is horizontal and has its bearings in the box B at the top of
the side A¹ of the frame A, and in the box B2 at the top of the standard a¹ which is
cast upon, or attached to, the horizontal bed or table a.
The driving pulley B³ is fixed upon the projecting outer end B' of the driving shaft. B.
At its inner end, the driving shaft is provided with the crank B, from which recipro-
cating motion is imparted, by means of the pitman C, to the carriage C. This carriage
is provided on its under side with the tongue which is seated in the horizontal
groove formed in the frame A. The said carriage C¹ is held down in its place by
means of the cap C bolted to the top of the side A2 of the frame A.
The carriage has secured therein the die D, the flat vertical surface of which is
provided with a series or system of parallel inclined ribs d.
The part of the bed a adjoining the side A2 of the frame A, is suitably slotted to
afford the necessary clearance for the moving parts of the machine.
A pinion fixed on the driving shaft B gears with the spur-wheel 6' fixed on the
horizontal cam-shaft E, which has its bearings in the box Eat the top of the side A¹
of the frame A, and in the box E2 at the top of the standard a² which is cast upon, or
attached to, the bed a.
Upon its inner end, the cam-shaft E is provided with a cam e. arranged to act upon
a roller e mounted upon a cam-pin or stud inserted in the arm, which is connected
with the carriage F, carrying the die . This die is provided upon its working surface
with a series of parallel inclined ribs. The carriage F is provided upon its under
side with a tongue F", which is slightly diagonal or inclined relatively to the working
surface of the die, and which is seated in a correspondingly diagonal or inclined
groove formed in the top of the horizontal plate G. This plate is supported upon
the bed a and is made adjustable thereon toward and from the side A2 of the frame A,
by means of the horizontal adjusting-bolts H, HP passed through the side A' of the
said frame and inserted into the plate G.
The plate G is to be rigidly secured, in any position to which it may be adjusted, by
means of the clamping screws h, h, which are provided with large collars or washers,
and are passed through holes in the plate G and inserted into the bed a, the holes in
the plate G being made large enough to permit the required range of adjustable
movement of the said plate G.
The vertical side of the carriage F is also diagonal or inclined relatively to the
working surface of the die f, as shown, and may be provided with a correspondingly
diagonal or inclined bearing along which it can slide; or, as shown in the drawings,
it may have a bearing against a series of anti-friction rollers i, fitted to rotate in
vertical bearings formed in the plate G and in the cap G' bolted to the top of a rib G
which is cast in one piece with, or attached to, the said plate G. The cap G¹ extends
over the top of the carriage F and holds it down in its seat.
The movement of the carriage F toward the driving shaft, which, for convenience,
is herein termed its forward movement, is effected by the rotation of the cam e. Its
return movement is effected by the retracting spiral spring J, which is connected at
one end to the hook Jat the lower end of a vertical arm Jinserted in the under side

page_text: of the carriage F, and extending downward therefrom through a suitable slot in the
The opposite end of the spring J is connected to the frame A.
bed a.
The limit of the backward movement of the carriage F is regulated by means of an
adjustable abutment screw J³ inserted horizontally through the end A³ of the frame A,
against the end of which screw the carriage F strikes at the termination of its backward
movement.
In will be seen that the lie secured in the carriage F makes one forward excursion
during each revolution of the cam-shaft E, and, at the end of its forward excursion, is
instantly retracted to its former position by the backward pull of the spring J; and
that, while making its forward excursion, the working surface of the die by reason
of the diagonal or inclined bearing afforded for the diagonal or inclined side of the
carriage F, moves in a slightly diagonal direction and thus gradually approaches the
plane in which the die D reciprocates; it will also be seen that the driving shaft B is
so geared to the cain-shaft E that it will make several revolutions while the said, cam-
shaft is making one revolution; and that, at each revolution of the said driving shaft B,
there is imparted from it, by means of its crank B and the pitman C, a forward and
backward movement to the carriage C carrying the die D.
The said driving shaft and cam-shaft are to be so geared together as to impart to
the die D'any required number of forward and backward movements while the die
is making one forward and backward movement. By the use of the gearing shown in
the drawings, the die D makes three forward and backward movements while the
die is making one forward and backward movement.
For convenience of adjusting the range of movement of the carriage C carrying the
die D, the crank B is provided with a radial slot for the reception of the crank-pin B6,
which is coupled to the forward end of the link or pitman C. The said crank-pin is
provided with a suitable shoulder, and is to be secured, in any position to which it may
be adjusted, by means of the jam-nut B'.
Various kinds of feed mechanism may be employed for feeding the blanks to the
machine. That shown in the drawings consists of the inclined ways or chute K., down
which the blanks, hanging by their heads, slide by their own gravity to the horizontal
part K of the said ways, which, as will be seen, is in alignment with the space between
the working surfaces of the two dies.
:
As a measure of precaution, although it will not, in all cases, be necessary, the
forward end of the carriage F is provided with the dividing finger F³, the point of
which, just before the carriage F completes its forward movement, enters the space
between the lowermost blank of the row of blanks in the ways, and the blank behind
it, and separates the lowermost blank from the blank behind it, and ensures its passage
from the lower end of the inclined portion of the ways to the forward end of the
horizontal portion of the ways, where it is in position to be transferred to the delivery
end K of the ways.
This transfer is effected by means of the sliding transferrer L provided with a cam-
pin which is arranged to he acted upon by the cam I mounted on the cam-shaft E.
The transferrer is a horizontally-sliding plate provided with suitable bearings and
sliding in a path parallèl with, and adjoining, the plane in which the face of the die 1)
reciprocates. By the rotation of the cam 7, the transferrer is drawn forward a little in
advance of the forward 'movement of the carriage F, in order to afford time for the
lowermost blank in the ways to reach the horizontal part of the ways, in front of the
end of the transferrer."
The transferring movement of the transferrer is effected by the retracting spring M,
one end of which is secured to a hook m inserted in the under side of the bed and
the other end to the hook on the lower end of the arm L³ projecting downward from
the transferrer L.
The limit of the backward movement of the transferrer L is determined by means
of an adjusting screw M which is inserted transversely through the arm L³, and.comes
against a shoulder forming a portion of the bed a.
The timing, of the moving parts in such that, when the die D makes its first
backward movement, after the disc has completed its backward movement a

page_text: blank N arrives in the position in which it is represented in dotted lines in
Figure 1. The result is that the shank of the said blank is caught between the
back end of the working surface of the die D and the forward end of the working
surface of the die f, as shown in Figure 5, and, by the backward movement of the die 1),
is rolled backward a prescribed distance along the face of the die f. The return move-
ment of the die D rolls the blank forward along the face of the die f, but, in the
mean time, the die has performed a portion of its forward movement, and the blank
is, therefore, retained between the faces of the two dies, instead of being rolled clear of
the die f, as it would have been if the said die 'had remained stationary. During the
succeeding backward and forward movements of the die D, the blank is rolled backward
and forward along the surface of the die f, until finally, at the end of the third backward
movement of the die D, when the screw-thread has been completely formed, the die
has moved so far forward that the finished screw is rolled off the back end of the die /;
and drops through an opening in the bed a upon the bench below, or into a receptacle
placed in position to receive it.
During these backward and forward movements of the die D, while the die f
is making its forward movement, the working surface of the said die gradually
approaches the plane in which the working surface of the die D moves; therefore,
during both the backward and the forward rolling movements of the blank upon the
surface of the die f, the oppositely inclined ribs upon the surfaces of the two dies are
gradually pressed deeper and deeper into the surface of the shank of the blank, until
finally a spiral thread is formed thereon of the desired depth, and of a shape corre-
sponding in cross section to the cross section of the spaces between the ribs of the dies.
It will be seen that both the backward and the forward movements of the die D are
rendered effective in impressing the thread upon the blank, by reason of the steady
approach of the die ftoward the plane in which the die D reciprocates; and it will
also be seen that the slow movement of the die in one direction, during the
reciprocating movements of the die D, (allowing the blank to be fed against the
forward end of the die f, and to be rolled back and forth along the surface of the said
die and to be finally discharged from the end of the said die opposite that to which
it was fed) permits the employment of comparatively short dies, which are inexpensive
in their construction, and easily replaced when worn..
Having now particularly described and ascertained the nature of the said invention,
and in what manner the same is to be performed as communicated to me by my foreign
Correspondent I wish it understood that I claim :-
First. A machine for the manufacture of screws, wherein ribbed dies are employed
between which the blanks are rolled, and one of which has two or
more reci-
procating or to-and-fro endwise movements imparted to it whilst the other die is
making a single endwise movement, with or without means for narrowing the space
between the dies during the rolling operation, for the purposes above specified.
Second. The combination, substantially as herein set forth, of two reciprocating dies
having their opposed surfaces suitably ribbed, means for giving to one of the said dies
a prescribed range of slow endwise movement in one direction and means for giving
in the same time to the other of the said dies two or more relatively rapid reciprocating
movements, for the purpose of rolling a screw-thread upon the body of a blank
introduced into the space between the two dies.
Third. The combination, substantially as herein set forth, of two reciprocating dies
having their opposed surfaces suitably ribbed, means for guiding the movements of
the said dies in planes slightly diagonal or inclined to each other, means for giving to
one of the said dies a prescribed range of slow endwise movement in one direction,
means for giving in the same time to the other of the said dies two or more relatively
rapid reciprocating movements, and means for feeding in the blanks, whereby a spiral
groove is impressed in the body of a blank fed into the space between the two dies and
is gradually deepened during the backward and forward movements of the quick-
moving die as the width of the space between the surfaces of the two dies gradually
diminishes.

page_text: Fourth. The combination, substantially as, and for the purposes, set-forth, of the
reciprocating die D, means for guiding the same and means for imparting a prescribed
range of reciprocating motion to the die-block or carriage in which it is secured, the
die, the carriage F, means for guiding the same in a path slightly diagonal or inclined
to the surfaces of the die f, means for imparting a slow forward movement to the
carriage F, and means for imparting a quick backward movement thereto, and the
adjustable abutment screw J³ for limiting the range of backward movement of the said
carriage F.
Fifth. In combination with the reciprocating dies D, /, the adjusting plate G for
regulating the position of the diagonal guide for the carriage F relatively to the plane
of motion of the die D, substantially as, and for the purpose, set forth.
Sixth. The combination, with the carriage and die ; of the cam e, the arm e
engaging with the said can and connected with the said carriage, and the retracting
spring J, substantially as, and for the purposes, set forth.
Seventh. The combination, with the die D and carriage C₁ of the pitman C, the
radially-slotted crank-arm B, and the adjustable crank-pin B, substantially as, and
for the purposes, set forth.
Eighth. The combination, substantially as set forth, of the reciprocating dies D, /,
the transferrer L, the ways K' for supporting a screw-blank in front of the end of the
transferrer and in alignment with the space between the working surfaces of the dies,
and means for, at the proper time, imparting end wise movement to the said transferrer
in a path parallel, or nearly parallel, to the plane of movement of the dies, for the
purpose of transferring the blank sidewise to the delivery end K2 of the said ways K',
and presenting it in position to be caught between the corners of the dies and rolled
into the space between the said dies.
Ninth. The combination, with the reciprocating dies D, /, the inclined ways K, the
horizontal ways K and the transferrer L, of the cam and the retracting spring M,
substantially as, and for the purpose, set forth.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant,