IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING OR CHASING THE THREADS OF SCREWS OR WORMS
Year: 1865

page_text: LETTERS PATENT to Joseph Green, of Leeds, in the County of York,
Machine Maker, for the Invention of "IMPROVEMENTS IN MACHINERY
OR APPARATUS FOR CUTTING OR CHASING THE THREADS OF SCREWS OR
WORMS."
Sealed the 22nd September 1865, and dated the 24th March 1865.
PROVISIONAL SPECIFICATION left by the said Joseph Green at the
Office of the Commissioners of Patents, with his Petition, on the
24th March 1865.
I, JOSEPH GREEN, of Leeds, in the County of York, Machine Maker, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
MACHINERY OR APPARATUS FOR CUTTING OR CHASING THE THREADS OF SCREWS OR
WORMS," to be as follows:-
The Invention consists in mounting a carriage or slide upon a lathe bed or
gantry of the ordinary kind. Upon this carriage or slide I place the fast and
loose headstocks of the lathe, which may be either cast upon or fastened to it.
The spindle of the fast headstock of the lathe is connected at its extreme end
with suitable gearing to the driving wheel, and upon it are cut worms or
threads. One part of the spindle having the worms or threads in one lateral
direction or towards the right hand, and the other part having them in the

page_text: contrary direction, or towards the left hand. On the side of the lathe bed
opposite to the cutting tool a rocking shaft is supported between brackets
fixed at each end of the machine. At the end of the rocking shaft, where the
loose headstock is mounted in the lathe, I attach a lever which may be worked
either by hand or foot, and which, by working it upwards and downwards,
causes the rocking shaft to vibrate or rock or partially turn. At the other
end of the rocking shaft I place adjustable half nuts, so arranged that when
the rocking shaft is moved in one direction by the lever one of the half nuts
will fit within the right-hand thread of the spindle of the fast headstock, and
cause both the fast and loose headstocks, and the carriage on which they are
mounted to traverse one way on the bed or gantry, whilst by turning or
moving the rocking shaft in the contrary direction the other half nut will fit
within the left-hand thread of the spindle, and cause the headstocks and
carriage to traverse the lathe in a contrary direction. On any convenient
part of the rocking shaft I place an adjustable lever, which is connected by a
jointed rod to a slide rest which holds the cutting or chasing tool; this tool
holder is mounted on a slide attached to the lathe bed, and can be brought up
to the screw to be cut, and also moved laterally so as to adjust it to the
length of cut required. The slide rest or tool holder is stationary, whilst the
screw or other article is being cut or chased, the screw or other article traversing
in front of the tool by the traverse of the carriage and headstocks. I so adjust
the position of the half nuts, and the connection of the adjustable lever and
jointed rod to the slide rest or tool holder, that when the rocking shaft is
actuated the half nuts will cause the lathe to traverse laterally first in one
direction and then in the opposite direction, whilst the lever and connecting
rod from the rocking shaft will also cause the slide rest or tool holder, and
the tool or chaser fixed upon it, to move in and out of contact with the screw
or other article to be cut or chased.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Joseph Green in the Great Seal Patent Office on the
23rd September 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
GREEN, of Leeds, in the County of York, Machine Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of March, in the year of our
Lord One thousand eight hundred and sixty-five, in the twenty-eighth year of

page_text: Her reign, did, for Herself, Her heirs and successors, give and grant unte
me, the said Joseph Green, Her special licence that I, the said Joseph
Green, my executors, administrators, and assigns, or such others as I, the
said Joseph Green, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN MACHINERY OR APPARATUS FOR CUTTING OR CHASING THE THREADS OF
SCREWS OR WORMS," upon the condition (amongst others) that I, the said Joseph
Green, my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
:-
NOW KNOW YE, that I, the said Joseph Green, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and to
the letters and figures marked thereon (that is to say)
This Invention consists in mounting B carriage or slide upon a lathe bed
or gantry of the ordinary kind, upon which are placed the fast and loose
headstocks of the lathe, which may be either cast upon or fastened to it. The
spindle of the fast headstock is connected at its extreme end by means of
suitable gearing to the driving pulleys; and upon this spindle are cut worms
or threads in one lateral direction, or towards the right hand, and the other
part having them in the contrary direction, or towards the left hand.
In the accompanying Drawing Fig. 1 is a plan view and Fig. 2 a
sectional view of a machine constructed according to this Invention; Fig. 8
is another sectional view taken in the line 1, 2, of Fig. 1.
A is the fast and B the loose headstock connected to the carriage; C is
the spindle upon which are cut the two threads D, D', one being a right-
handed and the other a left-handed screw. At the back of the lathe bed a
rocking shaft E is supported by the brackets F fixed at each end of the
machine. At one end of the rocking shaft is attached a lever G, which may
be worked either by the hand or the foot, but in the Drawing it is shewn as a
hand lever. By working this lever G upwards or downwards the rocking.
shaft E will partially turn on its axis. At the other end of the rocking shaft

page_text: are two bent arms H and H¹, one of them is bent downwards towards the
upper part of the spindle. D, and the other is bent upwards towards the under
part of the spindle. Each of these bent arms holds a half nut K, the thread
of which is similar to the thread of the spindle with which it is in contact.
When the rocking shaft E is turned by lifting the lever G, the bent arm H
will fit within the thread D¹ of the spindle C of the fast headstock, and will
cause both the fast and loose headstocks and the carriage on which they are
mounted to traverse on the bed or gantry of the lathe in the direction of the
arrow, whilst by lowering the lever G, and thereby turning the rocking shaft.
in the contrary direction, the other half nut H will fit within the threads D
of the spindle, and cause the headstocks and carriage to traverse the lathe in
a contrary direction. The threads D are much finer in pitch than the others
D', consequently, when working, the return of the carriage will, by reason of
the coarser pitch of the thread D¹, be quicker than when acting with the fine
pitch, which is in use while the cutting operation is being performed. On
some convenient part of the rocking shaft is placed an adjustable lever L,
which is connected by a jointed rod M to a slide rest which holds the cutting
or chasing tool. The slide rest or tool holder is mounted on a slide N attached
to the lathe bed, and is connected by the adjustable lever L and jointed rod M
to the rocking shaft, so that when the latter is actuated it will cause the slide
rest or tool holder, and the tool or chaser fixed upon it, to move in and out of
contact with the screw or other article to be cut or chased. The slide rest or
tool holder is stationary whilst the screw or other article is being cut or chased
on the spindle or other article, which is caused. to traverse in front of the tool
by the traverse of the carriage and headstocks caused by the half nuts H
and H. It also rests upon a slide Q which moves in a lateral direction.
O is a handle for giving a lateral movement to the slide rest by means of the
two bevil wheels and worm acting upon the slide Q for the purpose of adjusting
the tool holder to the length of the cut required, and P is the hand wheel or
handle for adjusting the loose headstock B by means of the ordinary worm.
R, R, are two gearing wheels, also fast to and moving with the fast headstock A,
and to allow of their gearing always being in connection with. the driving
pulleys S, S, they gear into the broad toothed wheel T, and thereby allow of
their traverse with the headstock A. The threads D¹ on the spindle will
require to be changed for different cuts of thread required. For this
purpose the spindle is taken out and a cylinder of a different thread is put
upon it, and fastened by a pin W, and a suitable nut inserted. in the bent
arm H.
X is an index wheel, with a pointer Y, and is for the purpose of
regulating the depth of cut by means. of the worm and handle Z. The

page_text: half nuts K are held in position by the heads of screws bracing both the bent
arm H and H¹ and part of the nut.
Having now described my Invention of improvements in machinery or
threads of screws or worms, and
apparatus for cutting or chasing the threads of screws
having explained the manner of carrying the same into effect, I claim as the
Invention secured to me by Letters Patent, as aforesaid, mounting the fast
and loose headstocks of a lathe upon a carriage which is capable of being
moved on the bed of the lathe as herein set forth.
In witness whereof I, the said Joseph Green, have hereunto set my
hand and seal, the Twenty-second day of September, in the year
Lord One thousand eight hundred and sixty-five.
JOSEPH GREEN. (L.S.)