Improvements in Machines or Apparatus for Cutting Screw-threads.
Year: 1899

page_text: Date of Application, 2nd Oct., 1899-Accepted, 23rd Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Machines or Apparatus for Cutting Screw-threads.
I, JOHN B. SIMONDS, residing at 119, Capitol Avenue, Hartford, County of
Hartford, State of Connecticut, United States of America, Tool Maker, do hereby
declare the nature of this invention, and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement-
My invention relates to a device for cutting screw threads and is particularly
adapted for use in the many forms of turret head screw lathes or other metal
working machines, in which the stock and tools are fed toward each other in the
same axial line during the cutting operation.
The object of my invention is to provide a device having the cutting die formed
of separable sections, which will be securely and positively held in proper align-
ment during the cutting operation and instantly released and separated when
a predetermined length of thread has been cut, thus allowing a rapid withdrawal
of the tool from the stock upon which it has been operating. Further to provide
positive automatic means for operating the sections of the die both in their open-
ing and closing movements.
To this end my invention consists, in the device as a whole, in the combination
of the parts, and in the details of such parts and their combination as hereinafter
described and more particularly set out in the claims.
Referring to the drawings:-
Fig. 1 is a plan view of the device.
Fig. 2 is an end view of the parts shown in Fig. 1 looking from the left.
Fig. 3 is an edge or side view.
Fig. 4 is a sectional view on the line - of Fig. 1.
Fig. 5 shows a plan view of a modified form of the device.
Fig. 6 is an end view of the device shown in Fig. 5 looking toward the cutting
dies.
Fig. 7 is a plan and end view of a portion of a metal working machine showing
my improvement attached to the turret, to illustrate its operation.
In the accompanying drawings the letter a denotes the base or support, ter-
minating at one end in a hollow shank b suitably formed to be inserted and held
in a tool holder such as is provided in the turret of an ordinary lathe. This sup-
port a has near its forward end an angular slideway a¹ adapted to control the
movement of and retain the slide blocks C, C', insuring the latter against all
movement whatever except in a line at right angle to the stock. A portion of
the base a, between the slide blocks and below and in the rear of the cutters is
cut away as at a² allowing free egress to chip or other waste material liable to
collect and clog the operation of the device.
Cutter sections d, d, are secured to these slide blocks in any suitable manner
as by screws e, e, the slide blocks being preferably mortised to provide a firm seat
for the cutter sections. The slide blocks with their cutter sections, when allowed
free movement, are forced apart along the slideway al by springs f, f¹, co-opera-

page_text: ting with a spring plug 2, the latter being of sufficient length to extend
within the slide blocks. acts both as a supplemental guide and stiffener for the
blocks. It will be readily seen from this construction and arrangement of the
slide-blocks and opening springs that, the instant the trip-block hereinafter des-
cribed, releases the slide-blocks, there is absolutely nothing to prevent an instan-
taneous and unrestrained separation of the slide-blocks and cutter sections.
Levers g, g, pivoted to the support a, and having ball and socket connections
with the slide blocks c, c respectively, confine the latter, with the cutter sections
to certain positions. The exact position and adjustment of the slide blocks and
cutters however, is determined by the position of the adjustable stop plates h, h³,
co-operating with the trip block k. These plates have a lateral adjustment on
their respective levers, slideways being provided in the levers, in which the plates
are moved and adjusted as by screws 2. The inner edges of the plates are cut
away, abrupt shoulders being thus formed as at 3. When the cutter sections
are in their closed or cutting position the shoulders ³ rest against the trip block k
a firm and rigid connection being thus formed to hold the cutters against separa-
tion
A trip lever i pivoted to the support as at i¹, and having an extension 22, trans-
mits the proper movements to the trip-block k, through the medium of a stud k¹.
This trip-blockk, moves in a suitable slideway formed in the support a, and is
normally forced forward to engage the shoulders 3 of the stop-plates, by the
spring bearing against the trip-lever i.
The letter denotes the closer. It consists of a spring pressed plug, mounted
within a suitable retainer in the support and provided with a cone shaped head
adapted to engage and force apart the levers g, g, together with the stop-plates.
upon coming in contact with a suitable cam surface. As will be readily seen, as
soon as the stop-plates are forced apart a sufficient distance, the trip-block under
the action of the spring 3, will be forced forward to engage and lie between the
shoulders 73.
In the modified form of my invention shown in Figs. 5 and 6, the base or sup-
port I, has slide-blocks 23 and operating levers 4 5 mounted upon it in the same
manner as in Fig. 1. The stop-plates 6 7 in this form, are integral with the
levers 4 5. The cutter sections 8 9 are mounted in suitable slideways formed in
the slide-blocks and are moved and adjusted by screws 10 11. Set screws 12 13
are employed to lock the cutter sections after they are once properly adjusted.
The trip-block 14, has an extension 15, underlying the stop-plates and pro-
vided with guide-slots 16 17. Pins 18 19 fast in the under side of the stop-plates
project within these slots and thus form a positive guide for the levers 4 5 in their
opening and closing movements.
It is obvious that in either of the forms shown, cutter sections forming dies of
various sizes may be used. The attachment and adjustment of these cutter sec-
tions being easily and quickly made, a device is obtained which may be used for
cutting threads of various sizes and of different pitch, a single device doing the
work which would ordinarily require several separate and costly tools.
The operation of the device is as follows:-
Referring to Fig. 7. The cutter sections being closed, the hollow shank of the
tool is inserted and clamped in one of the tool holders of the turret A, which is
adapted to be moved or fed toward the stock B, until the required work has been
nerformed upon said stock, then retracted and revolved until a second tool has
been brought into proper position to he fed toward the stock. As the turret and
tool are moved forward, the stock B is rotated rapidly and as it comes in contact
with the cutting die, a thread is formed upon the stock. When a predetermined
length of thread has been cut the extension 2 of the trip lever i comes in con-
tact with an adjustable stop m. located at a fixed point on the machine. The
trip block is forced from between the shoulders of the stop-plates and the cutter
sections, being absolutely unrestrained as to outward movement, are instantly

page_text: forced apart, and out of engagement with the stock, as shown in dotted outline.
The turret now retracts and during its revolution the cutter sections now open
are reset as the closer plug is forced upward by a cam surface n located on the
turret slide o.
From the construction of the device as here shown, it will be readily seen that
the timeing of the opening of the die may be adjusted to a nicety. Moreover the
cutting die being located at the extreme front of the device and having its cutter
sections movable in a line at right angle to the axis of the stock, allows the cut-
ting of a thread of uniform and full depth even up to a shoulder on the stock.
It is evident that other means than these shown herein may be employed to
secure the instant opening of the cutter sections and I do not wish to limit myself
to the exact means here shown, as any means for instantly releasing and opening
the several sections of the die without otherwise altering their position with rela-
tion to the support, will come within the scope of my invention.
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 :
1. In combination, in a screw cutting tool, a support, a sectional cutting die,
movably mounted in the support, and means for automatically and instantly
separating the sections of the die.
2. In combination, in a screw cutting tool, a rigid support, a sectional cutting
die mounted in the support and movable only in a line at right angle to the axis
of the stock operated upon, means for effecting an instantaneous, unrestricted
and direct outward movement of the sections of the die, and means independent of
the opening mechanism for closing the sections of the die.
3. În combination, in a screw cutting tool, a rigid support, a separable cutting
die mounted in the support and movable only in a line at right angle to the axis
of the stock operated upon, means for rigidly locking the sections in their closed
position, means for effecting an instantaneous, direct and unrestricted outward
movement of the sections of the die, and means independent of the locking and
opening mechanism for closing the die.
4. In a screw cutting tool, in combination, a rigid support, a separable cutting
die having a plural number of cutter sections mounted in the support and movable
only in a line at right angle to the axis of the stock operated upon, each inde-
pendently adjustable with respect to a common locking device, a trip device
adapted for locking and instantaneous releasing actions with respect to the cutter
sections, and means independent of the locking and releasing mechanism for
closing the cutter sections.
5. In combination, in a screw cutting tool, a support, a slideway formed in the
support, slide-blocks carrying cutter sections adapted to be moved along the slide-
way, levers for moving the slide-blocks having ball and socket connections there-
with, and automatic means for permitting an instantaneous and unrestrained
movement of the levers and appurtenant mechanism.
6. In combination, in a screw cutting tool, a support, slide-blocks carrying cut-
ter sections movably mounted in the support, levers for moving the slide-blocks,
a trip block, adjustable stop-plates mounted on the levers and adapted by their
position to determine the position of the slide-blocks and their cutter-sections.
and automatic means independent of the trip-block for forcing the levers and
appurtenant mechanism to their closed position.
7. In combination, in a screw cutting tool, a support, slide-blocks carrying
cutter sections movably mounted in the support, means for adjusting the cutter
sections, a trip-block adapted for locking and instantaneous releasing actions with
respect to the cutter sections, stop-plates adapted to engage the trip-block, to lock
the levers and appurtenant mechanism, and means independent of the trip mechan-
ism for forcing the cutter sections to their closed positions.

page_text: 8. In combination, in a screw cutting tool, a support, slide-blocks movable in
the support and provided with cutter sections mounted in position to have a full
and unobstructed field of operation on their work, means for permitting an in-
stantaneous direct and unrestricted movement of the slide-blocks and their cut-
ter sections from their working to their open position in a line at right angle
only to the axis of the stock operated upon, and means independent of the releas-
ing mechanism for forcing the slide-blocks and their cutter sections to their
closed position.
9. In combination, in a screw cutting tool, a rigid support, slide-blocks carry-
ing cutter sections movably mounted in the support and having movement only
in a line at right angle to the axis of the stock, levers controlling the movements
of the slide-blocks and having ball and socket connections therewith, automatic
means for locking or instantaneously releasing the levers and appurtenant parts,
and means independent of the locking and releasing mechanism for resetting the
die.
10. In combination, in a screw cutting machine, a rigid support, cutter sec-
tions movably mounted in the support, a movable trip mechanism adapted for
locking and instantaneous releasing actions with respect to the cutter sections,
and means interposed between the trip mechanism and cutter operating mechan-
ism for independently adjusting the several cutter sections.
Dated at Hartford, Connecticut, this 12th day of September 1899.
JOHN B. SIMONDS.
D. Young & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.