NEW OR IMPROVED MACHINERY FOR THE MANUFACTURE OF META LLIC SCREWS AND SCREW BOLTS AND OTHER METALLIC ARTICLES HAVING SCREW THREADS UPON THEM
Year: 1884

page_text: I JOHN SHELDON of N° 3 Wyndham Road Birmingham in the County of
Warwick Mechanical Engineer do hereby declare the nature of the said invention
for "NEW OR IMPROVED MACHINERY FOR THE MANUFACTURE OF META LLIC SCREWS
AND SCREW BOLTS AND OTHER METALLIC ARTICLES HAVING SCREW THREADS UPON
THEM" to be as follows:-
My invention consists of machinery constructed as hereinafter described for
the manufacture of metallic screws and screw bolts and other articles having
screw threads upon them such for example as augurs and gimblets gas tubes and
the like.
My invention is particularly applicable to the manufacture of iron screws of the
kind commonly called wood screws and I will describe it in connection with the
manufacture of wood screws.
The
My new or improved machinery is constructed essentially as follows.
screw blank on the body of which a screw thread is to be formed is supported in
a pair of jaws or claws carried by a spindle to which spindle rotary motion is
communicated.
On each side of the axis carrying the blank is a roll the axes of the said rolls
and that of the rotating blank being parallel and situated in the same plane The
said rolls rotate in the same direction and the blank situated between then and
operated upon by thein rotates in an opposite direction and with the same surface
velocity as that of the rolls. Each of these rolls is divided into several sectors
preferably four and each sector is provided with one or more projecting ribs or
threads having the same inclination to the axis of the roll as the screw thread to
be produced has to the axis of the screw. The diameter of the roll is such that
the projecting ribs or threads on each sector are of a length equal to the length
of the screw thread to be made on the blank. The several projecting ribs or
threads on the sectors are of different figures in cross section. The first sector has
one rib or thread preferably V shaped which rib by its action produces a ✓ shaped
groove in the blank the displaced metal causing the elongation of the blank. The
second sector has one rib or thread which is preferably of a shape suitable to give

page_text: the groove a trough like figure that is to make the bottom of the groove flat. The
third sector has two ribs or threads the space between which corresponds to the
figure of the thread which has been roughly formed by the second sector. By
the operation of this third sector the screw thread on the blank is nearly perfected.
The fourth sector may have its whole acting surface covered with ribs or threads
having in cross section a figure the exact counter part of that of the screw thread
to be made on the blank. By the action of the last sector the screw thread on the
blank is perfected.
The rolls and the spindle and jaws carrying the blank are geared together so
that the blank rotates on its axis or performs a rolling motion between the two
rolls similar to that which the motion of the rolls tends to impart to it. The screw
produced has a thread the diameter of which does not exceed that of the blank
operated upon the metal displaced by the action of the rolls travelling longitudinally
and lengthening the blank instead of escaping radially and increasing the diameter
of the thread.
In order to make the groove between the threads of progressively greater depth
from its commencement to the point of the screw the ribs or threads on the sectors
may be slightly eccentric the end of shortest radius coming first into operation.
In forming the screw thread on the point of the blank which tapers rapidly the
impressing ribs or threads of the rolls must approach each other rapidly. This
may either be effected by cams operating on the bearings of the rolls or by a
rapid increase in the diameter of the sectors at the parts which operate on the ends
of the screws.
Instead of making only one projection or thread on the first and second sectors
two projections or threads' may be employed:. By the use of two projections or
threads on the first and second sectors one complete thread is formed on the blank
and one side of another thread on each side of the complete thread: The formation
of one complete thread and half threads on opposite sides of it does not interfere
with the travelling of the displaced metal longitudinally as herein before described.
Dated this twenty eighth day of February 1884.

page_text: I JOHN SHELDON of No. 3 Wyndham Road, Birmingham in the County of
Warwick Mechanical Engineer, do hereby declare the nature of 'my invention for
NEW OR IMPROVED MACHINERY FOR THE MANUFACTURE OF METALLIC SCREWS
AND SCREW BOLTS AND OTHER METALLIC ARTICLES HAVING SCREW THREADS UPON
THEM and in what manner the same is to be performed to be particularly
described and ascertained in and by the following 'statement :-
My invention consists of machinery constructed as herein after described for the
manufacture of metallic screws and screw bolts and other articles having screw
threads upon them, such for example as augurs gimlets, gas tubes and the like.
My invention is particularly applicable to the manufacture of iron screws of the
kind commonly called wood screws and I will describe it in connection with the
manufacture of wood screws.
My new or improved machinery is constructed essentially as follows. The screw
blank on the body of which a screw thread is to be formed is supported in a
pair of jaws or clams carried by a spindle to which spindle rotary motion is
communicated.
On each side of the spindle carrying the blank is a roll the axes of the said rolls
and that of the rotating blank being parallel and situated in the same plane. The
said rolls rotate in the same direction and the blank situated between them and
operated upon by them rotates in an opposite direction and with the same surface
velocity as that of the rolls. Each of these rolls is divided into several sectors
and each sector is provided with one or more projecting ribs or threads having the
same inclination to the axis of the roll as the screw thread to be produced has to
the axis of the screw. The diameter of the roll is such that the projecting ribs or
threads on each sector are of a length equal to the length of the screw thread to
be made on the blank. The several projecting ribs or threads on the sectors are of
different figures in cross section. The first sector has one rib or thread preferably
V shaped which rib by its action produces a V shaped groove in the blank, the
displaced metal causing the elongation of the blank. The second sector has, one
rib or thread which is preferably of a shape suitable to give the grooves, a trough
like figure, that is, to make the bottom of the groove flat. The third sector has
two ribs or threads the space between which corresponds to the figure of the
thread which has been roughly formed by the second sector. By the operation of
this third sector the screw thread on the blank is nearly perfected. The fourth
sector may have its whole acting surface covered with ribs or threads having in
cross section a figure the exact counter part of that of the screw thread to be made
on the blank. By the action of the last sector the screw thread on the blank is
perfected.
i
The rolls and the spindle and jaws carrying the blank are geared together so
that the blank rotates on its axis or performs a rolling motion between the two rolls
similar to that which the motion of the rolls tends to impart to it. The screw
produced has a thread the diameter of which does not exceed that of the blank
operated upon the metal displaced by the action of the rolls travelling longitudinally
and lengthening the blank instead of escaping radially and increasing the diameter
of the thread.
'S!
In order to make the groove between the threads of progressively greater depth
from its commencement to the point of the screw, the ribs or threads on the sectors
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page_text: forming the screw thread on the point of the blank, which tapers rapidly, the
impressing ribs or threads of the rolls must approach each other rapidly. This
may either be effected by cams operating on the bearings of the rolls or by a rapid
increase in the diameter of the sectors at the parts which operate on the ends of
the screws.
:
Instead of making only one projection or thread on the first and second sectors
two projections or threads may be employed. By the use of two projections or
threads on the first and second sectors, one complete thread is formed on the blank
and one side of another thread on each side of the complete thread. The formation
of one complete thread and half threads on opposite sides of it does not interfere
with the travelling of the displaced metal longitudinally as herein before
described..
I will now proceed to describe with reference to the accompanying Drawings
the manner in which my invention is to be performed.
Figure 1 represents in side elevation and Figure 2 in plan machinery containing
my improvements; Figure 3 is an elevation of the front end of the machinery and
Figure 4 an elevation of the rear end of the machinery. The other Figures
represent parts of the machinery drawn to a larger scale than Figures 1, 2, 3 and 4
and also an illustrative diagram.
The same letters of reference indicate the same parts of the machinery in the :
several Figures.
The machinery is driven from the middle hollow shaft or spindle a working in
bearings b on the base c of the machinery. Rotary motion is communicated to
this shaft or spindle a from a steam engine or other prime mover by a band driving
the fast pulley d; e is a loose pulley for throwing the machinery out of gear with
the prime mover as is well understood. The front end of the spindle a carries the
jaws or clams g by which the blank h on which a screw thread is to be made is
held and rotated. The shank or body of the blank h is supported by a vertical
support underneath it not represented in the Drawing. The jaws or clams g are
constructed and operated precisely as jaws or clams in other screw making
machinery are constructed and operated and I do not think it necessary to describe
their construction and operation. The blanks to be screw threaded are supplied to
the jaws or clams g from a hopper by means of feeding mechanism which I do not
think it necessary to describe as the said feeding mechanism and hopper are
commonly employed in other screw making machinery. The rear end of the shaft
or spindle a carries a pinion i which gives rotation to the shafts / and l by means
of the trains of toothed wheels herein after described. The shafts k,l work in
bearings at the tops of the uprights m, m turning upon the shafts n, n. The front
ends of the shafts k, 1 carry the rolls p, q; p, q. The said rolls p, q; p, q rotate in
the same direction, the blank h to be screw threaded by the action of the said rolls
turning in an opposite direction and with the same surface velocity as that of
the rolls.
Figure 5 represents in front elevation and Figure 6 in side elevation one of these
rolls drawn of the full size. The two rolls p, q, exactly resemble one another.
I will therefore only describe one of the said rolls.
The roll p, q is made up of the disc or carrier p fixed on the shaft driving it and
separate pieces or sectors q, q fixed to the disc or carrier p by means of screw bolts
screwed into the said pieces or sectors as will be understood by an examination of
the drawing. Two, three or more sectors may be employed. In the Drawings
I have represented machinery having three sectors and in the diagram Figures 7
and 8 I have represented four sectors. Each of the sectors q is provided with one
or more projecting ribs or threads, the said ribs or threads having the same
inclination to the axis of the roll as the screw thread to be produced has to the
axis of the screw. The diameter of the roll and the length of each sector is such
that the projecting ribs or threads on each sector are of a length equal to the
length of the screw thread to be made on the blank. In the elevation Figure 6
the upper rib or thread r is that which operates first upon the blank and the lower
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page_text: rib or threads is that which operates next upon the blank. The relation of the
ribs or threads on the sectors to one another will be understood by reference to
Figure 7 which is a diagram representing the cylindrical surface of four sectors
and the ribs or threads upon them opened out into a plane figure and Figure 8
represents sections of the several ribs or threads on the sectors with elevations of
the screw thread which they respectively produce and perfect. The diagram
Figure 7 is drawn to a scale double that of Figures 1. 2. and 4 and the sections
Figure 8 are drawn to a scale double that of Figure 7. The first of the sectors q
may have one or two ribs or threads marked but I prefer two and of a V shape,
which ribs by their action on the rotating blank produce V shaped grooves in the
said blank, the displaced metal causing the blank to elongate in the direction of
its smaller end. The second of the sectors q has one or two ribs or threads,
preferably two, marked s which are of a shape to give the V shaped grooves
formed by the first sector a trough like figure, that is, to make the bottom of the
grooves on each side of the rib, flat. The third of the sectors q has two ribs or
threads marked t the spaces between which ribs or threads correspond to the thread
which has been roughly formed by the second sector. By the operation of this
third sector the screw thread on the blank is nearly perfected. The fourth of the
sectors q may have its whole acting surface covered with ribs or threads u having
in cross section a figure the exact counter part of the screw thread to be made on
the blank. By the action of the last sector the screw thread formed on the blank
is perfected. When I use three sectors as represented in the several Figures of the
machinery I employ ribs or threads of the kind marked in the diagram r, t and u.
By combining in the first sector one of the angular ribs or projections with one
of the square ribs of the second sector of the kind marked s in the diagram, the
second and third sectors may be omitted. In this case the angular rib or projection
of the kind marked r makes an angular groove into which the adjacent rib of the
kind marked s takes after the blank. has performed one rotation and flattens the
bottom of the said groove, the figure of the thread being afterwards perfected by
the action of a sector having ribs of the kind marked u.
The rolls p, q; p, q are adjusted and supported with the required nicety by
means of the adjusting screws w, w. These screws which work in screw boxes
formed near the summits of the strong brackets x, x on the base of the machine
bear against the arms or levers y, y turning upon the centres y², y² and carrying
near their upper ends rollers y³. These rollers y bear against the plain parts or
carriers p, p of the rolls p, q; p, q and maintain the said rolls at the required
distance apart.
In order to make the groove between the threads of the screw of progressively
greater depth from its commencement to the point of the screw the ribs or threads
on the several sectors are made slightly excentric the ends of the said ribs or threads
of shortest radius coming first into operation.
In order to form the screw thread on that part of the blank near its point where
the diameter of the blank rapidly diminishes the impressing ribs or threads of the
rolls must approach each other rapidly. This may be effected by means of cams
made to operate on the bearings of the rolls but I prefer to effect it by means of an
excentric 22 (see Figure 5) formed on the disc or carrier p of the roll near the point
at which the last sector terminates. These excentrics coming on the rotation of
the rolls against the bearing rollers y³, y³, the rolls pq; p q are made to approach
each other at the required times and to the required extent. The mechanism by
which the point of the blank is turned into a conical figure before the rolls p, q;p,q
operate upon it is the same as that employed in other screw making machines. This
mechanism is represented in the side elevation Figure 1 and plan Figure 2 but is
omitted in Figures 3 and 4. The said mechanism constitutes no part of my
invention and by its omission in Figures and 4 the essential and novel parts of
the machinery are more clearly exhibited.
In some kinds of wood screws the screw thread and the depression between the
convolutions of the thread; have the relation represented on a large scale in

page_text: Figure 9; that is, the thread of the screw has the same diameter as that portion of
the blank unoperated upon excepting at the end where the diameter of the thread
rapidly diminishes. The depression or groove between the convolutions of the
thread is shallow at the part nearest the head of the screw and gradually deepens,
its depth remains uniform until it approaches the point of the screw where it
rapidly increases, reducing the diameter of the screw to a point. In other words
the body of the screw (the thread being removed) first tapers from the original
diameter of the blank; then is cylindrical for the greater part of its length, and
finally rapidly tapers near the end to a point.
In making screws of this kind I prefer to employ rolls of the kind illustrated by
the said Figure 9 in which Figure the finishing sector marked u in Figures 7 and 8
is represented in contact with the finished screw. The roll represented is not
cylindrical but increases in diameter from the part which is nearest the head of
the blank towards the end. The exact sectional figure of the roll is represented in
Figure 10. On a roll of this kind the impressing ribs or projections herein before
described are made. When rolls of this kind are employed they do not require to
be made to approach each other during rotation as described with respect to the
rolls p, q in the several Figures and the said rolls consequently do not require the
eccentrics p2 Figure 5.
Rolls of the kind represented in Figures 9 and 10 may also be used for making
other kinds of screws besides screws of the kind shown in Figure 9, the section of
the roll without the impressing ribs or projections corresponding to the section of
the screw without its thread. In all cases where the rolls are of the kind last
described with reference to Figures 9 and 10 the mechanism for making the rolls
approach each other during rotation is dispensed with.
The hopper and feeding mechanism for supplying the blanks to the machine
I have marked with the letter f to distinguish them from the more essential and
novel parts of the machinery. The required motions of the hopper and feeding
mechanism are taken from a pulley on the shaft k by means of the band f2.
The clams g are operated through the hollow spindle a in the ordinary way.
The
The rolls p, q; p, q are driven from the shaft a in the following manner.
pinion on the rear end of the shaft a gears with the toothed wheel 2. The
toothed wheel 2 gears with the toothed wheel 3. A pinion 4 carried by the axis of
the toothed wheel 3 gears with the toothed wheel 5, a pinion 6 on the axis of
which gears with the toothed wheel 7. The toothed wheel 7 is on one end of a
sleeve, the other end of which carries the toothed wheel 8. The toothed wheel 8
gears with the toothed wheel 10 fixed on the shaft 7 of the left hand roll Figure 4.
The roll on the right hand side Figure 4 is driven from the pinion 6 by means of
trains of wheels the counter part of those just described, that is, the said pinion 6
gears with the toothed wheel 72 on the end of a sleeve, the other end of which
carries the toothed wheel 8%. The toothed wheel 82 gears with the toothed
wheel 102 fixed on the spindle of the right hand roll (see Figure 4).
I will now briefly describe the action of the machinery.
The rolls p, q; P, q being adjusted and supported at the proper
by means of the screws w, w and rotatory motion being given to the shaft a, a
blank is fed into the machine and gripped and held by its head in the claws or
clams and is put into rapid rotatory motion. The blank is fed between the
rolls, when three or two sectors are employed, when those portions of the rolls
having no sectors upon them are opposed to each other, When four sectors are
employed the last portion of each of the fourth sectors is removed in order to allow
sufficient room between the rolls, when the said cut away parts are opposed to each
other, to permit of the introduction between them of the blank. By the rotation
of the rolls, the ribs or threads on the several sectors of the said rolls are in
succession made to operate upon the blank and produce a screw thread upon it,
the rapid rotation of the blank and the slow rotation of the rolls being so arranged
with respect to each other that the surface motion of the blank and that of the
soctors of the rolls is at the same rate. In other words the rate of rotation given
11
distance apart

page_text: to the blank is that which the rolls would tend to communicate to it if it had no
rotary motion of its own. After a complete rotation of the two rolls pq; p q, the
screw thread is formed and by the opening of the clams g the screw thus made is
removed from the machine in the ordinary way. The screw produced has a thread
the diameter of which does not exceed that of the blank from which it is made, the
metal displaced by the action of the rolls travelling longitudinally, thereby
lengthing the blank instead of escaping radially and making the thread of the
screw produced of greater diameter than the blank from which it is made.
Although I have described the method which I prefer to employ of making up
the impressing rolls p, q and which method of construction I find to answer well
in practice, yet the said rolls may be built up in other ways; or each roll may
consist of one piece of steel instead of being made up of the carrier p and the
sectors q, q. And although I have only described my invention as applied to the
manufacture of a screw of the kind called a wood screw yet my invention is
applicable to the manufacture of metallic screws and screw bolts in general and to
other metallic articles having screw threads upon them, such for example as augers,
gimlets, gas tubes and the like.
The application of my invention to the manufacture of metallic screws and screw
bolts and other metallic screwed articles differs in no essential respect so far as the
formation of the screw thread is concerned from the application of my invention to
the manufacture of wood screws herein before described, the size of the rolls and
the sectional figure of the ribs or projections upon them being varied to suit the
size of the screws and screwed articles to be wormed or screw threaded and the
configuration of the screw thread to be produced.
Articles other than screws may be fed into the machine by hand the hopper and
feeding mechanism and the pointing mechanism herein before described being in
that case dispensed with.
•
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-The new or improved machinery for the manufacture of metallic screws
and screw bolts and other metallic articles having screw threads upon them herein
before described and illustrated in the accompanying Drawings; that is to say,
machinery consisting essentially of a pair of rolls rotating in the same direction
and with the same surface velocity as the blank or article on which a screw thread
is to be made, the said blank or article having an independent rotation between
the said rolls in a direction contrary to that in which the rolls rotate, the said rolls
having on different portions of their acting surfaces projecting ribs or threads of
the kind and arranged as herein before described and represented, by the successive
action of which projecting ribs or threads a screw thread is formed on the blank or
article in such a way that the displaced metal travels longitudinally and the screw
thread made has a diameter not exceeding that of the blank or article operated
upon.