A CERTAIN IMPROVEMENT OR CERTAIN IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING SCREWS
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
WHITWORTH, of Manchester, in the County Palatine of Lancaster, Machinist,
send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth;
by His Royal Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Twenty-seventh day of February, in the fourth year
of His reign, and in the year of our Lord One thousand eight hundred and
thirty-four, did, for Himself, His heirs and successors, give and grant unto
me, the said Joseph Whitworth, my executors, administrators, and assigns, Ilis
especial license, full power, sole privilege and authority, that I, the said Joseph
Whitworth, my exécutors, administrators, and assigns, or such others as I, the
said Joseph Whitworth, my executors, administrators, or assigns, should at any
time agree with, and no others, from time to time and at all times hereafter
during the term of years therein expressed, should and lawfully might make,
use, exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "A CERTAIN IMPROVEMENT OR CERTAIN IMPROVEMENTS IN
MACHINERY OR APPARATUS FOR CUTTING SCREWS;" in which said Letters Patent
is contained a proviso, obliging me, the said Joseph Whitworth, by an instru-
ment in writing under my hand and seal, particularly to describe and ascertain
the nature of my said Invention, and in what manner the same is to be per-
formed, and to cause the same to be inrolled in His Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, 1, the said
Joseph Whitworth, do hereby declare that the nature of my said Invention
and the manner in which the same is to be performed, are particularly
described and ascertained in and by the following description thereof, reference
being bad to the Drawings hereunto annexed, and to the letters and figures
marked thereon (that is to say):-
:-
My Invention of certain improvements in machinery or apparatus for
cutting screws consists in an improved construction of stock or frame for
holding the cutters or dies which form the thread, and in the mode of forcing
up the dies or cutters simultaneously for cutting the screws; and, secondly, in
the improved construction of a machine, by which cutters acting upon a similar
principle may be made to produco threads upon cylindrical shafts of the length
and diameter required, by the power of a steam engine or other moving power.
The means by which the dies can be made to move simultaneously admit of
considerable variation in the arrangement and construction of the parts by
which that result is attained; I have therefore shown in the accompanying
Drawings several different methods of obtaining that result, which although
different in detail, effect the same movement of the cutters or dies.
Figure represents the external appearance of one of my improved con-
struction of hand stocks, with the dies shewn in their proper places; Figure 2
is an edge view of the same. Figure 3 exhibits the interior of the stock, the
cover of ne box being removed to expose the parts, and shewn reversed
at Figure 4; Figure 5 is a longitudinal section, taken through the middle of
the stock, when complete, us in Figure 2. a, a, a, are the dies, accurately
fitted into grooves formed partly in the box b, b, and partly in the cover c, c.
which enables them to slide in radial directions; d is a wheel placed within
the box, and turning in a circular recess formed in the box and cover. This
wheel has oblique teeth cut in its periphery; and c is a tangent screw intro-
duced into a cylindrical recess, also partly in the box and partly in the cover.
The threads of this screw take into the teeth on the edge of wheel d, and,
consequently, on giving rotation to the screw o the wheel d is driven round.
Three excentric curved recesses ff.f, are cut in the interior of the wheel d,
which curves respectively bear against the back parts of the dies a. . It will
be perceived that by turning the tangent screw e the wheel d will be driven
round, and that, by the smaller radio of the curves coming against the backs
of the dies a, they will be simultaneously forced inwards.
The improved construction of machine or engine for cutting screws by
power is shewn in the Drawings at Figure 6, which is a plan or horizontal
representation of the machine; Figure 7, a longitudinal elevation of the

page_text: same, partly shewn in section; and Figure 8, an end view, in which several
Figures similar letters point out corresponding parts.
A, A, A, is the bed or frame of the machine, constructed somewhat like
the bed and slide frame of a lathe, with fixed standards B, B, in which
the main shaft C revolves, and at the same time slides longitudinally. A
toothed wheel D is connected to the shaft C by a key passed through its
boss, which key takes into a longitudinal groove cut along the shaft,
and shewn in Figure 7; hence it will be perceived that though the wheel
D is so connected to the shaft as to communicate rotary motion thereto,
yet the shaft is permitted to slide longitudinally within the boss of the
wheel D. Rotary motion is given to the wheel D by a pinion E fixed
upon the auxilliary shaft F, F, which shaft is supported in bearings with
plummer blocks on a lateral frame G, G, shewn best in the horizontal view,
Figure 6. This auxilliary shaft has two pullies H and I turning freely upon
it, and to each of these pullies a clutch box is affixed, with a sliding clutch K
between them, and a tumbling lever L, for the purpose of locking either of
the pullies to the shaft, in order that the shaft may be turned in contrary
directions, as circumstances may require. This part of the machine will be
best understood by reference to the detached Figure 9, which is a partial cle-
vation of the auxilliary shaft and its appendages. From the pullies II and I
bands M, M, one of them being crossed, extend to corresponding pullies fixed
upon a shaft N above, which shaft, being driven by the power of a steam
engine or any other first mover, gives rotary motion through the bands M, M,
in contrary directions to the pullies H and I, and, according to the position in
which the trip lever L is placed, as shewn by dots in the last-mentioned Figure,
so will the shaft be locked to one of the pullies, and be made to revolve in
either direction, or the clutch being in the central position and unlocked from.
either pulley, the shaft will remain quiescent. The box or holder containing:
the screw dies is shewn at P in Figures 6, 7, and 8; it is fixed to a frame Q;
which is capable of being slidden upon the edge rails of the bed A, A, and of
being made fast to the bed by screw bolts. The dies contained in this box are
worked upon a similar principle to those described under the first head of the
Invention, but their construction is in a slight degree varied, as will be here-
after explained. The blank shaft or cylindrical piece upon which the screw is
intended to be cut is shewn at R in Figures 6, 7, and 8, one end of it being
made fast in the universal chuck holder S, which is fixed to the end of the
main shaft C, by the rotation and sliding longitudinal movement of which shaft
the screw blank is passed through the dies, and thereby the worm or thread is
cut round its surface. The progress of the main shaft C in its longitudinal

page_text: movement is dependant upon a leading screw T, the axis of which is coincident
with the axis of the main shafts, and they are connected together at their
extremities by the end of the scrow T being inserted into a socket in the cud
of the main shaft, confined therein by a flange and collar, as shewn by dots in
Figure 7, thereby allowing the shaft to revolve independantly of the screw T.
The screw T passes through a screw box U, which box turns freely in the neck
of the bearing V, and is made to revolve by the toothed wheel W fixed upon
it, the object of which is that rotary motion may be given to the screw box Ụ
instead of turning the screw T itself, in order that the screw with the shaft C
may be made to slide longitudinally. By this contrivance, a screw T of any
convenient pitch of thread may be employed to conduct tho main or sliding
shaft for cutting any desired pitch of screw upon the black shaft R, and tho
progress longitudinally of the screw T and sliding shaft C, which determines
the rake or obliquity of the screw or thread to be cut upon the shaft, may be
regulated by varying the diameters of the train of wheels connected to the
auxilliary shaft F and wheel W. which tho scrow box U is driven, for
according to the rotary speed of the screw box U so will the guide or lending
screw T and the shaft C he made to advance longitudinally, and as the rotary
speed of the screw box is increased or diminished so will the rake of the screw
be more or less obliquely cut upon the blank shaft R. In order to limit the
extent to which the screw thread shall be cut by the dies upon the blank shaft.
adjustable stops X, X, are placed upon a sliding bar, which advances with the
sliding shaft, and at the proper times, according to their adjustment; these
stops act upon the trip lever L and throws it over, so as to move the clutch
and reverse the direction of the longitudinal movement.
Figure 10 shews the internal construction of the box or frame containing the
dies or cutters a, a, a, the stems of which, in this instance, fit in cylindrical holes
formed radially in the inner ring piece shewn detached at Figure 11, and the
hinder parts of the stems of the dies are acted upon by the curved excentric
recesses, y. y. y, formed in the outer ring of the box, as shown in Figure 10.
There are also curved excentric ribs,,, placed parallel to the curved recesses
which act in notches cut in the under sides of the stems of the dies. It will
now be perceived that the inner ring being fastened to the frame Q. as shown.
in the section, Figure 7, with the outer ring sliding round upon it, that by
giving to the outer ring a partial rotary movement by means of a weighted
lever Y, the dies will be made to approach toward or recede from the centre.
Figure 12 shews the cover of the box removed. I would remark, that if it
should be thought desirable the frame Q with the box P and cutting dics
might be made to travel on the bed A, A, during the time the thread of the

page_text: screw is being formed on the screw blank R. In this instance shaft C and
screw blank R would revolve without moving longitudinally, and the frame Q
and dies be moved by a leading screw passed through a screw box on the
frame Q, the rotary motion of the leading screw would be communicated from
the shaft F in the same way as that described from the screw box U, or in any
other convenient manner.
Figures 13 and 14 are representations of another method of effecting the
same movement of the cutters or dies by inclined planes or wedge pieces
instead of the excentric grooves before described.
Figure 13 is a representation of the box or holder of the dies, the front plate
being removed; Figure 14 is a section of the same complete. y, y, are
wedge-shaped pieces, placed in mortices in the box or holder, the inclined
planes of which act against the ends of the stems or blocks containing the
dies; there are projecting pins or studs upon those wedge pieces, which work
in slots formed in the front plate, which is shewn detached in Figure 15. On
turning this plate partly round, the slots, by the connection with the wedge
pieces, will move them forward and force the dies inward.
Figures 16 and 17 are representations of another method of effecting the
simultaneous movement of the dies by means of levers, and which arangement
will also draw back the dies when required. y, y, are bent levers, the ends of
which work in grooves formed in the stems or holders of the dies. These levers
have their fulcrum on pins in the box or holder, their other ends having pro-
jecting studs which work in the slots in an outer ring, as before described; on
turning the ring partly round in the direction of the arrow the lever will be
made to force the dies forward, and on turning it the reverse way they will be
drawn back into the former position.
Figures 18 and 19 represent another method of obtaining the same move-
ment of the dies by means of screws and wheel and pinions. y, y, y, are
screws formed on the ends of the stems or holders containing the dies,
having bevelled pinions with screws cut in the bosses working upon them.
The bosses of the pinions are kept up to the inner ring by a groove and pin.
There is a longitudinal groove cut in the stems or holders, with pins
working in them to prevent their turning round. There is a bevelled toothed
wheel working on a projection on the inner ring, which wheel takes into the
several pinions, and on turning this wheel backward or forward the pinions
will be made to revolve, and by their movement will force outward or inward
the dies.
Having now described my improvements in machinery or apparatus for
cutting screws, it will be evident that the same is applicable to the cutting or

page_text: forming threads of various kinds of screws, particularly those used in latches,
vices, or jacks, and also to machinery or apparatus for screwing bolts, or for
forming what are called wood screws.
Lastly, I wish it to be understood that I claim particularly as my Invention
the manner of bringing the several dies forward simultaneously in their im-
proved stocks, holders, or frames by the means and for the purposes above
described.
In witness whereof, I, the said Joseph Whitworth, have hereunto set my
hand and seal, this Twenty-seventh day of August, in the year of our
Lord One thousand eight hundred and thirty-four.
JOSEPH (L.B.) WHITWORTII.
AND BE IT REMEMBERED, that on the Twenty-seventh day of August,
in the fifth year of the reign of His Majesty King William the Fourth, the
said Joseph Whitworth came before our said Lord the King in His Chancery,
and acknowledged the instrument aforesaid, and all and every thing therein
contained and specified, in form above written. And also the instrument
aforesaid was stamped according to the tenor of the Statute made in the fifty-
fifth year of the reign of His late Majesty King George the Third.
Inrolled the Twenty-seventh day of August, One thousand eight hundred
and thirty-four.