Improvements in Forming Screw Threads on Continuous Lengths of Wire.
Year: 1888

page_text: Date of Application, 1st Feb., 1888
Complete Specification Left, 1st Nov., 1888
Complete Specification Accepted. 21st Dec., 1888
Improvements in Forming Screw Threads on Continuous Lengths
of Wire.
I WILLIAM HENRY DORMAN of The Hawthorns, Newport Road Stafford, in the
county of Stafford Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN FORMING SCREW THREADS ON CONTINUOUS LENGTHS OF WIRE to
be as follows:-
My Invention consists in forming a screw thread on the surface of a continuous
wire by means of pressure, that is to say, raising one thread up out of the solid
material instead of cutting it as is the method at present in use.
The wire, on the surface of which, it is desired to form the thread, being coiled on a
spool, is fed through a pair of guide rolls, which prevent it from revolving, but at the
same time feed it forward at the desired speed. The guide rolls are placed directly in
front of a pair of concentric dies, so that the wire, immediately after passing through
these rolls, enters and passes between the dies.
The dies consist of a roller, and of a ring, arranged concentrically.
On the circumference of the roller, and the interior surface of the ring are formed
indentations, such that, when a wire is passed between them while they are in motion,
it receives the impression of a screw thread.
To the dies, a rotating movement is imparted by means of suitably arranged
gearing.
The rotative movement and the relative velocities imparted to the dies respectively,
cause them to roll round the wire, which is, at the same time, fed forward between
the dies at a speed proportionate to the pitch of the screw it is desired to raise.
After leaving the dies, the wire with the thread now raised upon it, is carried
forward and again coiled upon a spool suitably arranged for that purpose.
In my invention, as above described, the wire does not revolve, but the dies roll
round it.

page_text: I
may,
however cause the wire to revolve in passing through the dies, the direction
and velocity of the revolution of the dies respectively being varied accordingly.
Instead of concentric dies, as above described, I may also use two or more rollers
with screw threads formed on their surfaces, acting on the surface of the wire and
raising the thread as above described.
11
Improvements in Forming Screw Threads on Continuous Lengths
of Wire.
1, WILLIAM HENRY DORMAN of The Hawthorns, Newport Road, Stafford, in the
county of Stafford, Engineer do hereby declare the nature of this invention and in
what manner the same is to be perforined, to be particularly described and ascertained
in and by the following statement :-
My invention consists in forming a screw thread on the surface of a continuous
wire by means of a rolling pressure, that is to say, forming the thread partly by
depressing & partly by raising it, out of the solid material, instead of cutting it out,
as is the method at present in use.
The wire upon which it is desired to form the thread, is fed through a pair of guide
rolls which prevent it from revolving, but at the same time feed it forward at the
required speed. The guide rolls are placed directly in front of a pair of rolling dies,
so that the wire, immediately after passing through these rolls; enters and passes
between the dies.
The dies consist of a roller and of a ring, arranged one within the other. To the
dies a revolving movement around their own axes respectively is imparted, by means
of suitably arranged gearing, and at the same time by means of the rotation of the
frame that carries them, the revolving dies are made to travel round the wire. On
the circumference of the roller and the interior surface of the ring, are formed.
- indentations, such that when-a-wire of suitable size-is- passed between-the-roller and
the ring while they are in motion, it receives the impression of a screw thread.
The wire is fed forward between the rolling dies at a speed properly proportioned
to the pitch of the screw, it is desired to form.

page_text: My invention is illustrated by the accompanying drawings in which :-
Fig. 1 is a side elevation of the machine.
Fig. 2 is a plan.
Fig. 3 is a front elevation.
Figs. 5 & 6 are a front elevation and section respectively of the thread raising
apparatus, shewing the roll and ring in position, and the gearing for driving the
same.
Figs. 7 & 8 are a front elevation and section respectively, of the frame for carrying
the thread-raising arrangement.
Fig. 9 is a sido elevation of the roll, shewn in position within the ring, the latter
partly in section.
Fig. 10 is a section of the intermediate gears.
Fig. 11 is an elevation of the pivot for carrying the roll.
Figs. 12 & 13 are a front elevation and section respectively shewing a modification
of the arrangement of the roll and ring, with the gearing for driving the same.
Figs. 14 & 15 are a front elevation and section respectively of a modification of the
roll and ring to be used with the arrangement shewn in Figs. 5 & 6, 7 & 8, 10 & 11,
and in place of the roll and ring shewn in Fig. 9.
Fig. 16 is a view shewing the worm fand friction screws f².
The same letters refer to the same parts in all the figures.
"A" is the main frame of the machine, which may be fixed to a suitable bench or
table.
In the upper portion of this main frame are bearings B, B¹ in which a hollow
shaft C revolves, driven by the band-pulley D.
Fixed upon the main frame A-concentrically with the hollow shaft C is a pinion or
toothed wheel F through which the hollow shaft C'passes. Upon the front end of the
hollow shaft C which projects beyond the pinion F, is mounted the frame G which
contains the mechanism for forming the thread.
At the opposite or rear end of the hollow shaft C is secured a toothed wheel H
which, in conjunction with the intermediate wheels I and J mounted on the frame A,
drives the wheel K secured upon the horizontal shaft L.
The shaft L revolves in the bearings M, M, upon the frame A and carries upon the
one end a worm N which gears with the worn wheel O.
The worm wheel O is fast upon the vertical spindle P upon the lower end of which,
a gear wheel is also fixed. Gearing into the wheel Q is a similar wheel R carried
by another vertical spindle S. The two spindles P & S revolve in long bearings T & U
which are mounted in vertical grooves of rectangular section formed in the opposite
sides of the portion V of the main frame A, which stands up in front of the frame G.
On the upper ends of the spindles P and S are secured the wire feeding rolls W & X
which are formed with grooves around their circumference.
The grooves are formed with small projections or teeth, to cause them to grip the
wire. The feed rolls W & X are pressed together upon the wire by means of pressure
screws acting on the long bearings T & U.
Upon the rear end of the shaft L is secured a worm "b" which gears into a worm
wheel c.
The worm wheel c is formed on the hollow shaft c¹ revolving in the bearing d on the
main frame A.
Through the hollow shaft c', another hollow shaft "7" passes, which carries the
driving plate & pins g that give motion to the reel "
e.
ג:
On the other end of the hollow shaft g is fixed the worm "f." Sunk in the
substance of the worm "f" are screws which bear upon the end of the hollow
shaft c' and draw the driving plate g against the opposite end of the shaft c¹.
The pressure of the screws on the shaft c¹ is equalized by the intervention of
springs and a revolving washers. The worm """ gears with a worm wheel / fast
upon a shaft i revolving in the bearing j.

page_text: દઃ
"
Upon the shaft i, and revolving with it, is a cam k, which acts on a bell-crank
lever, pivotted at m and by means of the rod " n "which passes through the
hollow shaft g, causes the reel e to travel to and fro, so that the finished wire lies
regularly from side to side as the reel revolves.
A guide o assists to secure regularity in the winding.
The frame G on which is carried the thread raising mechanism, is mounted on, and
revolves with the hollow-shaft C.
On the back of the frame G is a gear wheel "p" meshing into the fixed pinion F,
and is secured to a short spindle q, which revolves in a bearing
frame G.
tr.
" formed in the
Attached to the spindle "g" is a pinion s which gears with the toothed-ring t. The
ring t revolves in a circular recess in the frame "G, and in which it is retained by
the ring cover vand screws
20,"
The geared ring t carries the ring or external die-roll
formed, upon the wire, hereinafter more particularly described.
by which the thread is
At the back of the frame G, opposite to the wheel p, and gearing with the fixed
pinion F, is another gear wheel b₁ secured to one end of the spindle d', which revolves
in a bearing e' in the frame G.
On the other end of the spindle d' is the pinion which gears with the wheel g³,
which is secured to the wheel h³, and revolves with it upon the pivot fixed to the
frame Gat j¹.
The wheel gears with the wheel A¹ to which is attached the internal rolling die l¹
which is further hereinafter described.
The wheel and the roll ', both revolve together upon the pivot "m¹" carried by
the frame G at "n¹."
.
The ring "y" and roll are made of hardened steel, and have upon their acting
circumferences, spiral teeth or threads or screw forming indentations of a pitch or
distance apart, and of a shape, and at an angle suitable for producing the required
thread upon the wire when the latter is fed forward by the feed rolls W & X.
The action of the machine is as follows:-A coil of wire of suitable diameter for the
screw desired, is drawn down at one end (for a distance rather more than enough to
reach from the rolling dies to the reel) sufficiently small to allow it to pass between the
dies without touching them.
This small end of the wire is passed between the rolling dies and through the
hollow-shaft C, and made fast to the reel "e." The hollow shaft C is set in motion,
movement is communicated by the train of gearing already described, to the
spindles P & S, and the feed rolls W & X are made to revolve in the direction
required, to feed forward the wire into the machine. The wire is gradually carried
through between the rolling dies, which, by means of the spiral threads above
mentioned, form upon it a screw thread along the whole length of wire.
The worm upon the shaft L drives the worm wheel c in the direction required for
winding on the finished wire, and at a speed greater than that required to be given to
the reel "e," the object being that, as the reel is driven by a friction mechanism, a
constant strain may be kept on the wire, so as to coil it up tightly on the reel, and to
aid the action of the feed rolls W & X in feeding the wire through the machine.
The amount of strain upon the wire is capable of adjustment by increasing or
decreasing the amount of friction in the frictional driving mechanism by means of
the sunken screws already mentioned. The worm ""revolving in the same
direction, and at the same speed as the reel "e" by means of the intervening
mechanism already described, causes the reel "e" to travel to and fro across the path
of the wire, so that the finished wire Z is wound evenly upon the reel.
As the frame G carried on the hollow shaft C revolves around the centre of the
wire, it carries around with it the entire mechanism including the roll and the
ring "y"
The wheel "p" upon its spindle "q" is thus carried around the fixed pinion F,
into which it gears, and the pinion s at the front end of the spindle "q" gearing into
the toothed ring t, gives motion to the die ring "y."

page_text: In the same manner the wheel 6 upon its spindle d', also gearing into the fixed
pinion F, gives motion through its train of wheels ƒ¹, g³, h¹, and k¹ to the die roll .
Now, by properly proportioning, upon the principles well known to mechanics, the
diameters and numbers of teeth in these two sets of gearing, the roll and the
ring "y" are made to roll around the wire as it is supplied by the feed rolls W and X,
with a minimum of rubbing or twisting action.
It has been found in practice that to produce the best result, the angle of the
thread in the dies should be such that, during one revolution of the frame G, the
thread advances a distance equal to half the pitch of the screw desired, and the feed
given to the wire by the feed rolls W & X for one revolution of the frame G should
also equal half the pitch of the thread upon the wire.
The distance apart of the threads in the die, is equal to
threads on the screw.
the distance apart of the
and the ring y² have the
cutting plain and separate
of a screw-the distance
In the modification shewn in Figs. 12 and 13, the roll
threads or teeth or screw forming indentations formed by
grooves around their circumferences, and not in the form
apart of these grooves is equal to the distance between the threads required to be
raised upon the wire.
The roll and the ring y² are set in the frame G₁ at angles such that the teeth
upon each shall lie at the same angle as the angles of the thread required to be raised
upon the wire.
The interior circumference of the ring y² where the teeth are formed, is somewhat
bell-mouthed, to allow of the wire keeping a straight line as it passes between the
roll and the ring.
The trains of gearing that drive the roll and the ring y² are similar to those
already described, and shewn in Figs. 5 to 11, except that the pinion s the ring t¹,
the wheel ², and the wheel 2 Figs. 12 & 13, must be bevel gears to suit the angle
of inclination given to the roll and ring.
The proportions of the trains of gearing must be such as to cause the roll and ring
dies to roll, as already described.
In this modification, the amount of the feed given to the wire for every revolution
of the frame G, must equal the pitch of the screw desired.
The modification shewn in Figs. 14 & 15 is to be used with the frame G, and its
trains of gearing as first described.
The teeth or screw forming indentations in the roll 13 and the ring y³ Figs. 14 & 15
are formed by separate ring grooves around their circumferences, and have no spiral
inclination. They are the same distance apart as the threads required upon the wire, and
the roll may be either parallel or taper, as may also the hole in the ring y³, where the
teeth are formed.
In all other respects this roll 13 and ring y³ are exactly similar to the roll and
ring y, and occupy the same place in the frame G.
The feed given to the wire for each revolution of the frame G is equal to the pitch
of the screw upon the wire.
Although I have described a method of carrying out my invention of forming a
screw on a continuous wire, by partly depressing & partly raising the thread out of
the material which operates with revolving dies rolling around the wire, I may also
use similar dies in a machine in which the ring and roll revolve on their axes only,
and the wire is made to revolve between them.
In a machine for this purpose so constructed, the rolling action on the surface of
the wire would be the same as in the machine already described, but the reel which
winds up the finished wire, and the swift that carries the un-threaded wire, would, in
that case have to be made to revolve.
Also, I may use instead of the rolling dies consisting of a roller, working within a
ring, two or more rollers with screw forming indentations, arranged around the wire,
and their peripheries acting upon it, and I may make these rollers either revolve
around the wire as well as revolve, on their own axes, or 1 may make them revolve
on their own axes only, and the wire revolve between them.

page_text: Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1st. On a continuous wire, the formation of a screw partly by depressing and
partly by raising the screw thread out of the material.
2nd. In a machine for the formation of a screw thread on a continuous wire-The
use of rolling dies consisting of a roller working within a ring between which the
wire passes, and which revolve upon their own axes respectively, and at the same
time revolve around the wire as a common centre, the exterior surface of the roller,
and the interior surface of the ring being furnished with screw forming indentations.
3rd. In a machine for the formation of a screw thread on a continuous wire-The
use of rolling dies consisting of a roller working within a ring between which the
wire passes and which revolve upon their own axes, the wire revolving between them,
the exterior surface of the roller and the interior surface of the ring being furnished
with screw forming indentations.
4th. In a machine for the formation of a screw thread on a continuous wire, the use
of two or more rollers which are arranged around the wire and revolve upon their
own axes, at the same time that they roll around the wire, and which have screw
forming indentations upon their peripheries.
5th. In a machine for the formation of a screw thread on a continuous wire, the use
of two or more rollers which are arranged around the wire, and revolve upon their
own axes, at the same time that the wire revolves between them. The rollers having
screw forming indentations upon their peripheries.
6th. In a machine for the formation of a screw thread on a continuous wire, the
combination of the rolling dies consisting of a roller working within a ring with feed
rolls the exterior surface of the roller and the interior surface of the ring being
furnished with screw forming indentations.
7th. In a machine for the formation of a screw thread on a continuous wire the
combination of the rolling dies, consisting of a roller within a ring, with feed rolls
and with a frictionally driven reel, the exterior surface of the roller, and the interior
surface of the ring being furnished with screw forming indentations.
8th. In a machine for the formation of a screw thread on a continuous wire, the
combination of two or more rollers, having screw forming indentations on their
peripheries, with feed rolls and with a frictionally driven reel.
9th. A machine for the formation, on a continuous wire, of a screw, partly by
depressing and partly by raising the screw thread out of the material, with thread
Forming dies or rollers, feed rolls, hollow spindle, frictionally-driven winding reel, and
arrangements for regularly laying the wire on the reel, substantially as described.
Dated this 31st day of October 1888.