IMPROVEMENTS IN MACHINERY FOR THE MANUFACTURE OF SCREWS."
Year: 1876

page_text: LETTERS PATENT to William Charles Stiff, of Birmingham, in the County of
Warwick, Merchant and Manufacturer, and Abraham Bowen, of Birmingham,
aforesaid, Mechanical Engineer, for the Invention of "IMPROVEMENTS IN
MACHINERY FOR THE MANUFACTURE OF SCREWS."
PROVISIONAL SPECIFICATION left by the said William Charles Stiff and
Abraham Bowen at the Office of the Commissioners of Patents on the 4th
October 1876.
"
WILLIAM CHARLES STIFF, of Birmingham, in the County of Warwick, Merchant
and Manufacturer, and ABRAHAM BOWEN, of Birmingham, aforesaid, Mechanical
Engineer. IMPROVEMENTS IN MACHINERY FOR THE MANUFACTURE OF SCREWS."
Our Invention has reference to that method of manufacturing screws in which
the rod, bar, or blank to be converted into a screw is operated upon by rolls having
screw threads formed on them, by the action of which screw-threaded rolls screw
threads are impressed or formed upon the rod, bar, or blank operated upon by
them.
Our said Invention consists in the construction and arrangement of the parts
of the said machinery herein-after described, whereby the efficient working of the
machinery is more effectually secured than in like machinery as ordinarily
constructed.
We employ a series of three rolls of large diameter compared with the diameter
of the rods, bars, or bolts to be screwed. The said rolls have the required screw
threads formed upon them. Two of the said rolls are mounted in fixed bearings,
their axes being parallel and by preference in the same horizontal plane. The
other or third roll is situated over the other two, its axis being in a plane midway
between the planes in which the axes of the lower rolls are respectively situated.
The bearings of the upper roll are not fixed, but are capable of sliding vertically in
slides formed in the framing of the machine. The rising and falling motion of the
top roll is produced by a shaft situated over it, the said shaft carrying excentrics,
the clips of which being connected with the bearings of the said roll give the
required rising and falling motion to the said roll on the rotation of the shaft
carrying the excentrics. The said shaft is geared to the principal shaft of the

page_text: machine by toothed gearing, which gives one rotation to the excentric shaft to
three rotations of the rolls. We do not limit ourselves to that proportion.
The motion of the rolls is effected as follows-The principal shaft of the machine
carries a crank, the pin of which engages in a hole in the middle of a vertical plate,
having in it three holes situated equidistantly from each other and from the middle
hole in which the crank pin of the principal shaft engages. The end of the axis
of each roll has a crank, the pins of which cranks enter the three holes respectively
of the said plate. The cranks on the axes of the lower rolls are of the same length
as the crank on the end of the principal shaft, but the crank of the upper roll is
capable of lengthening and shortening itself to accommodate the rising and falling
of the said upper roll. This lengthening and shortening of the crank of the upper
roll is effected by fixing the crank pin on a slide which works in a groove in the
crank, and by the motion of the said slide in the said groove the crank pin can
take a position at a greater or less distance from the axis of the roll. The crank
pin on the said slide of the upper roll engages in one of the holes in the plate
carried by the crank on the principal shaft in the same way as the crank pins of
the lower rolls engage in the other two holes.
The action of the machine is as follows:-Rotation being given to the principal
shaft, its crank gives a like rotation to the three rolls through the plate carried by
it, in the holes in which plate the crank pins of the three rolls engage. At the
same time the principal shaft through the gearing described communicates a slow
rotation to the shaft of the excentrics, thereby slowly raising and lowering the top
roll. The lengthening and shortening of the crank of the top roll permits of the
roll rising and falling without its rotary motion being affected. The bar or bolt
to be screwed is introduced by preference in a cold state between the rolls when
the top roll is at its highest point. The descent of the top roll causes the bar or
bolt to be grasped by the three rolls, by which a rotatory motion is given to it and
the screw threads on the rolls impressed upon it. On the ascent of the top roll the
screw rod or bolt may be removed from the machine.
The lengthening and shortening of the crank of the top roll may be effected in
other ways than the one described, for example, the crank pin may be fixed in the
hole in the plate carried by the crank of the principal shaft, and engage in a slot
or groove in the crank on the top roll with the same effect.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Charles Stiff and Abraham Bowen in the Great Seal
Patent Office on the 29th March 1877.
WILLIAM CHARLES STIFF, of Birmingham, in the County of Warwick, Merchant
and Manufacturer, and ABRAHAM BOWEN, of Birmingham, aforesaid, Mechanical
Engineer. "IMPROVEMENTS IN MACHINERY FOR THE MANUFACTURE OF SCREWS."
Our Invention has reference to that method of manufacturing screws in which
the rod, bar, or blank, to be converted into a screw is operated upon by rolls having
screw threads formed on them, by the action of which screw-threaded rolls screw
threads are impressed or formed upon the rod, bar, or blank operated upon by
them.
Our said Invention consists in the construction and arrangement of the parts of
the said machinery herein-after, described, whereby the efficient working of the
machinery is more effectually secured than in like machinery as ordinarily
constructed.
We employ a series of three rolls of large diameter compared with the diameter
of the rods, bars, or bolts to be screwed. The said rolls have the required screw
threads formed upon them. Two of the said rolls are mounted in fixed bearings,
their axes being parallel and by preference in the same horizontal plane. The
other or third roll is situated over the other two, its axis being in a plane midway

page_text: between the planes in which the axes of the lower rolls are respectively situated.
The bearings of the upper roll are not fixed but are capable of sliding vertically in
slides formed in the framing of the machine. The rising and falling motion of the.
top roll is produced by a shaft situated over it, the said shaft carrying eccentrics,
the clips of which being connected with the bearings of the said roll give the
required rising and falling motion to the said roll on the rotation of the shaft
carrying the eccentrics. The said shaft is geared to the principal shaft of the
machine by toothed gearing, which gives one rotation to the eccentric shaft to three
rotations of the rolls. We do not limit ourselves to that proportion.
The motion of the rolls is effected as follows:- The principal shaft of the
machine carries a crank, the pin of which engages in a hole in the middle of a
vertical plate having in it three holes situated equidistantly from each other and
from the middle hole in which the crank pin of the principal shaft engages. The
end of the axis of each roll has a crank, the pins of which cranks enter the three
holes respectively of the said plate. The cranks on the axes of the lower rolls are
of the same length as the crank on the end of the principal shaft, but the crank of
the upper roll is capable of lengthening and shortening itself to accommodate the
rising and falling of the said upper roll. This lengthening and shortening of the
crank of the upper roll is effected by fixing the crank pin on a slide which works
in a groove in the crank, and by the motion of the said slide in the said groove the
crank pin can take a position at a greater or less distance from the axis of the roll.
The crank pin on the said slide of the upper roll engages in one of the holes in the
plate carried by the crank on the principal shaft in the same way as the crank pins
of the lower rolls engage in the other two holes.
The action of the machine is as follows:-Rotation being given to the principal
shaft its crank gives a like rotation to the three rolls through the plate carried by
it in the holes, in which plate the crank pius of the three rolls engage. At the
same time the principal shaft through the gearing described communicates a slow
rotation to the shaft of the eccentrics, thereby slowly raising and lowering the top
roll. The lengthening and shortening of the crank of the top roll permits of the
roll rising and falling without its rotatory motion being affected. The bar or bolt
to be screwed is introduced by preference in a cold state between the rolls when the
top roll is at its highest point. The descent of the top roll causes the bar or bolt to.
be grasped by the three rolls, by which a rotatory motion is given to it and the
screw threads on the rolls impressed upon it. On the ascent of the top roll the
screwed rod or bolt may be removed from the machine.
The lengthening and shortening of the crank of the top roll may be effected in
other ways than the one described, for example, the crank pin may be fixed in the
hole in the plate carried by the crank of the principal shaft and engage in a slot or
groove in the crank on the top roll with the same effect.
We will now describe with reference to the accompanying, Drawings the manner
in which our Invention may be performed.
Figure 1 represents in side clevation a machine for the manufacture of screws
containing our improvements, and Figure 2 is a cross section of the machine taken
on the dotted line A, A, Figure 1, the top roll of the machine being represented at
its highest position; Figure 3 is an end clevation of the machine taken at the
right-hand end of the machine, Figure 1; Figure 4 is a part elevation of the middle
standard or upright of the machine and the driving gear of the rolls, the said
Figure 4 being taken on the line B, B, Figure 1, looking towards the threaded rolls;
and Figure 5 is a longitudinal section of the same; Figure 6 is a plan front
elevation and side elevation of the crank pin and slide by which the top threaded
roll is driven; in Figures 4, 5, and 6 the positions of the cranks and crank pins
of the driving mechanism are different from the positions of the corresponding
parts in Figure 1.
The same letters of reference indicate the same parts in the several Figures of
the Drawings.
a, b, c, are the three threaded rolls of the machine, a, b, being the pair of bottom

page_text: rolls, and c the top roll, the said top roll having the position with respect to the
bottom rolls a, b, represented in Figure 2. The axes a, b, of the lower threaded
rolls a, b, turn in fixed bearings in the uprights c, c, but the axis of the top
threaded roll c works in bearings d, d, capable of sliding vertically in guides
formed in the said uprights e, e, for the purpose of giving a rising and falling
motion to the said top roll, as herein-after explained. The rising and falling
motion of the top roll c is effected by a horizontal shaft parallel to the axes of
the rolls a, b, c, the said shaft f carrying eccentrics g, g, which act upon clips h, h,
the latter being connected to the rod i which passes through the sliding bearings
d, d, of the axis of the said top roll c. Motion is transmitted from the principal or
driving shaft working in the upright e and step bearing c³ to the shaft f
carrying the eccentrics g, g, by the following arrangement of gearing:-On the said
driving or principal shaft is a pinion l, which gears with a toothed wheel mon
the parallel shaft n. The shaft n of the toothed wheel m carries a pinion p, which
gears with a toothed wheel g on the shaft f of the eccentrics. By giving motion
to the shaft through the gearing l, m, p, q, a slow.rising and falling motion is
imparted by the eccentrics g, g, and clips h, h, and sliding bearings d, d, to the top
roll c, one rotation being given to the eccentric shaft f by the said gearing to three
rotations of the principal or driving shaft, and consequently three rotations of the
threaded rolls a, b, c.
The rotatory motion of the rolls a, b, c, is transmitted from the driving shaft / by
the following arrangement of parts. On the inner end of the said driving shaft
is a crank, the pin of which engages in a hole s in the middle of the circular
plate t. The said plate t has in it three equidistant holes marked respectively tº,
t3, t, (see Figure 4), and the end of the axis of each roll has a crank upon it, the
pins of which cranks enter the three holes t, to, t, respectively of the said plate t.
The crank of the axis of the roll a is marked a, and its pin a. The crank of the
axis of the roll bis marked 63, and its pin 6, and the crank of the top roll c is
marked c³, and its pin c. The three cranks a³, 63, c³, are of the same length, but
the pin c of the crank c³ is not fixed rigidly to the said crank, being formed on
the slide which works in a groove of in the said crank c³, as best seen in
Figures 4, 5, and 6. The crank c³ of the top roll is thereby capable of lengthening
and shortening itself to accommodate the rising and falling of the said top roll, the
crank pin by the motion of the slide e taking a position at a greater or less
distance from the axis c² of the said top roll c, according to the vertical height of
the said top roll c from the bottom rolls a, ს.
By an examination of Figures 4, 5, and 6, it will be seen that the arrangement
by which the lengthening and shortening of the crank cof the top roll c is effected
permits of the top roll e rising and falling without affecting the rotatory motion of
the said top roll, the said top roll rotating at the same speed as the bottom
rolls a, b.
Instead of effecting the lengthening and shortening of the crank c³ of the top
roll c by the arrangement described and represented, the same object may be
attained by fixing the crank pin c of the said crank c on the plate t, and causing
the said crank pin to engage in a slot or groove in the crank c³.
In this arrange-
ment the slide is dispensed with.
By the rotation of the principal shaft a like rotatory motion is transmitted
through the plate and cranks and crank pins a³, a, b, b, c³, c, to the three rolls
a, b, c, the top roll c being at the same time slowly raised and lowered by the
eccentrics and clips g, h, operated from the shaft f, and the latter driven by the
gearing herein-before described.
When the top rolle is at its highest point, as represented in Figures 1 and 2,
the bar, rod, or blank to be screwed, marked u in Figure 2, is introduced between
the three rolls a, b, c. By the descent of the said top roll c the bar, rod, or blank u
is grasped between the three rolls, by which a rotatory motion is communicated to
it and the screw threads on the said rolls impressed upon the said bar, rod, or
blank. On the ascent of the top roll c the screwed rod or bolt u may be removed

page_text: from the machine and another rod or blank introduced and screwed in the manner
described.
Having now described the nature of our Invention, and the manner in which the
same is to be performed, we wish it to be understood that we do not limit ourselves
to the precise details herein-before described and illustrated, as the same may be varied
without departing from the nature of our Invention; but we claim as our Invention
of improvements in that class of machinery for the manufacture of screws in which
a set of three screw-threaded rolls is used for impressing a screw upon the rod, bar,
or blank operated upon the top screw-threaded roll of the set of threaded rolls
having a rising and falling motion given to it, the construction and arrangement or
combination of the parts herein-before described and illustrated in the accompanying
Drawings for driving or giving a rotatory motion to the said set of screw-threaded
rolls of the machine, and for permitting of the top threaded roll rising and falling
without its rotatory motion being affected thereby, that is to say, giving a rotatory
motion to the said set of screw-threaded rolls by means of the cranks a³, 63, c³, on
the axes of the said rolls, the crank pins a, b, c, of the said cranks taking into
equidistant holes in a circular plate t driven in the manner described and illus-
trated, and lengthening and shortening the crank cof the top roll for permitting
of the rising and falling motion of the said top roll by making the crank pin c¹ of
the crank upon a slide c working in a groove in the said crank c³, or forming
the crank pin ct upon the plate t and causing it to work in a slot or groove in the
crank c³, substantially as hercin-before described and illustrated.
In witness whereof, we, the said William Charles Stiff and Abraham Bowen,
have hereunto set our hands and seals, this Twenty-eighth day of March,
in the year of our Lord One thousand eight hundred and seventy-seven.
Witness to the signature of
AL
W. C. STIFF.
(L.S.)
Witness to the signature or
William Charles
Stiff,
W. T. WHITEMAN.
Witness to the signature of
Abraham Bowen,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
W. C. STIFF.
(L.S.)
ABRAHAM BOWEN, (L.S.)