Improvements in Die Heads for Screw Cutting and in the Method of Operating the same.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Die Heads for Screw Cutting and in the Method
of Operating the same.
I, WILLIAM JOHN SMITH, of The Geometric Drill Company's Factory, West-
ville, Connecticut, United States of America, Engineer, do hereby declare the
nature of this invention to be as follows:-
This invention relates to improvements in die heads for screw cutting and
to the method of operating the same.
The object of the present invention is to produce a simple and easily operated
device capable of application to either a hand or mechanically operated turret
cutting machine, whereby a screw of any desired length may be accurately cut,
and in which the cutting operation can automatically be stopped when a screw
of any predetermined length has been cut; without the complication involved
when the stop mechanism is located in the bore of the sleeve carrying the die
head.
By means of this invention a very considerable length of screw can be cut
continuously, and the cutting means be released and freed from the work by a
simple mechanism contained in the die head, operated by the relative move-
ments of the die head and the sleeve carrying the die head brought about by
the stoppage of movement of the carrying sleeve attached to and moving in
unison with the turret or other mounting and its slide. The stoppage of the
carrying sleeve its turret and slide being brought about by contact between
a part thereon and a fixed stop on the base in manner well understood amongst
engineers and machinists using such class of tools, whilst the die head con-
tinues its forward movement awhile that is to say the screw cutting or thread-
ing dies are mounted on a skeleton holder or carrier which is connected to a
locking and releasing sleeve by the intervention of a spring actuated cam
piece, the position of the cam piece determining the positions of the dies, in
the working or idle positions, whilst the cam ring is controlled by a locking
bolt actuated by a handle, and mounted on the sleeve.
The dies having been placed and adjusted to their correct working position
on the article to be threaded the work is revolved and is acted upon by these
dies and the threading proceeds to the desired adjusted extent, until the slide
carrying the turret and dies has reached the end of its travel which travel is
determined by the contacting of an adjustable screw rod or equivalent part
upon the slide with a fixed part on the base, or stationary support therefor,
carried by the bed of the machine.
I provide a skeleton carrier in the front of which are carrying parts which
form between them the slide ways for the holders to which the cutting
dies-say four in number-corresponding with the parts holding and guiding
them but this number of cutters, holders and guideway may be varied.
The hollow shank portion of the carrier into and through which the screw as

page_text: it is cut can pass and project according to the length of the work. This hollow
shank has mounted upon it a spring actuated cam piece and locking and releas-
ing sleeve, as well as a coiled spring and retaining ring kept in place by screws.
The spring serves normally to keep the locking sleeve pressed against the
cam piece.
The sleeve is entered in the example described into one of the holes in the
turret of the slide mounted on the bed.
The locking sleeve has mounted on it the crescent shaped index plate to be
described and on this is mounted the eccentric bolt capable of being partially
rotated by a handle formed with a slide way for a taper ended lock bolt which
enters one or other of two holes formed in the rear face of the index plate
when brought opposite them owing to the rear pressure exerted by the coiled
spring located behind and holds the handle and thereby the bolt in either of
its operative positions in its bolt hole in the rear face of the cam piece. The
acting end of this eccentric bolt is formed with its circular projecting end eccen-
tric to the stem on which it is mounted, when turned to right or left it will
bring the relatively greater or less diameter, or extent of projection, of the cam
end against the end of the recess it engages, in the cam piece and so regulate the
position of the cam grooves therein relatively to the projecting lugs or studs
on the rear face of the die holders engaged therein, thereby enabling two
positions of the cutting dies to be attained, and either at will, without the
necessity of deranging the general adjustment of the parts, when set for such
denths of cut.
Thus the one position of the handle-that to the right hand-viewing the
die head from the rear-holds the cutters in position for effecting the "rough-
ing" cutor shallower first cut and the other position-that to the left hand
will hold the cutters in position for effecting the deeper or finishing" cut in
the work.
A ring mounted on the shank and secured thereto by screws serves to retain
the cam piece in place relatively to the flange of the carrier.
Upon this ring is an abutment piece against which one end of the coiled
spring which is laid around a recess in the cam piece whilst the opposite end
of that spring abuts against a like piece on the cam piece.
The constant tendency of this spring is to cause the cam ring to rotate and
by its rotation to draw the studs outwards from the centre of the die-head and
away from the work, whilst any relative rotative movements of the parts is pre-
vented by reason of the feather keys formed on or secured to the shank and
engaging in correspondingly shaped recesses in the sliding sleeve.
There are handles secured in the cam piece to rotate it by hand, or in the
rotation of the turret (to bring the successive cutting tools into operative posi-
tion) the projection or stem comes in contact with the slide or a fixed part
thereon and in the continued movement of the turret this stem is held, thus
moving the cam ring relatively to the die holders and to the locking sleeve
bringing all parts into position for operation on the work and locking them so.
Screws secure the cutters in their holders.
The adjustment of the depth of cut of the dies is effected by varying the
positions of the inclines or grooves relatively to the studs and this change of
position is effected by releasing the screw nuts which are secured in the pro-
jecting ends of bolts."
These bolts have heads which are countersunk into holes formed in a crescent
shaped plate which plate is located in the groove in the sleeve and the stems
of these bolts thence pass through sleeve and through the index plate to receive
the nuts.
These bolts and nuts serve to clamp the three parts tightly together in their
adjusted position the adjustment being assisted by the position of the index
point relatively to the index graduations cut or mounted on the periphery of
the flanged part,

page_text: By this arrangement of the crescent shaped plates I obtain a broader base for
the bearing of the bolts heads and nuts on the parts to be clamped.
In operation the die head having been placed in position in the hole in the
turret and the work having been brought up to the cutting dies these dies
perform their function on the rotating rod, to be screwed, until the desired cut
has been completed, when a part on the travelling slide held in adjusted position
by a lock screw comes in contact with a stop within the base on the bed causes
the motion of the slide to be arrested and thereby arresting the motion of the
turret and consequently of the sleeve with the parts affixed to it, but by reason
of the hold of the cutters on the threads of the work, being screwed and the
continued rotation of that work, the cutters, their holders the carrier and the
attached cam piece continue to be moved forward, until the extent of their
movement relatively to the now arrested sleeve becomes sufficiently great to
separate the eccentric end of the bolt from its bolt hole putting meanwhile the
spring in compression. As soon as this bolt is thus released the spring is free
to expand and to rotate the stop piece and cause the cam ring to be partially
rotated thereby drawing outwards from the centre the lugs or studs and with
them the attached holders and cutters free from the work.
By these means I am enabled to dispense with the presence of any tripping
or stop mechanism for releasing the cutters from the work at the completion of
the cut within the sleeve or tool proper thereby leaving a perfectly free way
for any required length of screwed stem to pass therethrough, avoiding the
inconvenience which arises from the clogging of such stop mechanism when so
internally placed and also I can dispense with the holes usual for securing
such internal stop parts.
Dated the 4th low of Databan 1900
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.
Improvements in Die Heads for Screw Cutting, and in the Method
of Operating the same.
I, WILLIAM JOHN SMITH, of The Geometric Drill Company's Factory, West-
ville, Connecticut, United States of America, Engineer, do hereby declare the
nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
This invention relates to improvements in die heads for screw cutting and
to the method of operating the same.
The object of the present invention is to produce a simple and easily operated
device capable of application to either a hand or mechanically operated turret
cutting machine, whereby a screw of any desired length may be accurately cut,
and in which the cutting operation can automatically be stopped when a screw
of any predetermined length has been cut, without the complication involved
when the stop mechanism is located in the bore of the sleeve carrying the die
head.
By means of this invention a very considerable length of screw can be cut
continuously, and the cutting means be released and freed from the work by a
simple mechanism contained in the die head, operated by the relative move-
ments of the die head, and the sleeve carrying the die head, brought about by
the stoppage of movement of the carrying sleeve attached to and moving in

page_text: unison with the turret, or other mounting, and its slide. The stoppage of the
carrying sleeve, its turret and slide, being brought about by contact between
a part thereon and a fixed stop on the base, in a manner well understood amongst
engineers and machinists using such class of tools. whilst the die head con-
tinues its forward movement awhile, that is to say, the screw cutting or thread-
ing dies are mounted on a skeleton holder, or carrier. which is connected to a
locking and releasing sleeve, by the intervention of a spring actuated cam
piece, the position of the cam piece determining the positions of the dies, in
the working or idle positions, whilst the cam ring is controlled by a locking
bolt, actuated by a handle, and mounted on the sleeve.
The dies having been placed, and adjusted to their correct working position
on the article to be threaded, the work is revolved, and is acted upon by these
dies, and the threading proceeds to the desired adjusted extent, until the slide
carrving the turret and dies has reached the end of its travel, which travel is
determined by the contacting of an adjustable screw rod, or equivalent part
upon the slide, with a fixed part on the base, or stationary support thereof,
carried by the bed of the machine.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shows by a vertical section the construction of a die head according
to the invention.
Fig. 2 is an external view of Fig. 1.
Fig. 3 is a front view of the same, showing the dies in their working position.
Fig. 4 is a similar view to Fig. 2 but with the dies in their released position,
and spring open to release the work.
Fig. is a cross section taken on the line A, B, of Fig. 2.
Fig. 6 is a side view, partly in section of the die holder or skeleton carrier.
Fig. 7 is an end view of the same.
Fig. 8 is a face view of the cam plate or cam ring.
Fig. 9 shows a perspective view to a smaller scale of a turret lathe operated
by hand with one of the improved die heads mounted thereon.
Figs. 10, 11, 12 and 13 show details illustrating parts of the mechanism
separately.
a is the skeleton carrier (shown separately in Figs. 6 and 7) in the front of
which are the carrying parts 1, 2, 3, 4, which form between them the slide ways
for the holders b, to which the cutting dies (here shown as four in number) 5, 6.
7, 8, corresponding with the parts holding and guiding them, but this number of
cutters, holders and guideway may be varied.
a¹ is the hollow shank portion of the carrier into and through which the screw
as it is cut can pass and project according to the length of the work.
This hollow shank has mounted upon it the spring actuated cam piece c, and
the locking and releasing sleeve d, as well as the coiled spring o. and retaining
ring f. This ring f is kept in place by screws fl f¹, one of which is seen in
Fig. 2. The spring e serves normally to keep the locking sleeve d pressed
against the cam piece c.
The sleeve d is entered in the example illustrated into one of the holes A¹ in
the turret A of the slide B mounted on the bed A (see Fig. 9).
The locking sleeve d has mounted on it the crescent shaped index plate m
(shown separately by Fig. 12) to be described, and on this is mounted the eccen-
tric bolt, capable of being partially rotated by handle g¹, and this handle g¹
is formed with a hole which forms a slideway for a taper ended lock bolt g²,
which enters one or other of two holes, m, m2, formed in the rear face of the
index plate m, (best seen in the separate view Fig. 12) when brought opposite
them, owing to the rear pressure exerted by the coiled spring g, located behind,
and holds the handle gl and thereby the bolt g, in either of its operative positions
in its hole in the rear face of the cam piece c. The acting end of this eccen-
tric bolt ༡ is formed with its circular projecting end g³ eccentric to the stem on

page_text: which it is mounted when turned to right or left it will bring the relatively
greater or less diameter, or extent of projection, of the cam end g³ against the
end of the recess it engages, in the cam piece c, and so regulate the position
of the cam groove c, c therein relatively to the projecting lugs or studs 62, 63
on the rear face of the die holders bengaged therein, thereby enabling two
positions of the cutting dies to be attained, and either at will, without the
necessity of deranging the general adjustment of the parts, when set for such
depths of cut.
Thus the one position of the handle-that to the right hand-viewing the
die head from the rear-holds the cutters in position for effecting the " rough-
ing cut" or shallower first cut, and the other position-that to the left hand
will hold the cutters in position for effecting the deeper or finishing cut in
the work.
33
h is a ring mounted on the shank and secured thereto by screws entered
into holes 3, 3, and this ring serves to retain the cam piece e in place relatively
to the flange a² of the carrier a. Upon this ring his the abutment piece h¹
projecting into the recess against which abuts one end of the coiled spring i
which is laid around this recess in the cam piece c whilst the opposite end
of that spring abuts against the like piece on the cam piece.
The constant tendency of this spring is to cause the cam ring c to rotate
and by its rotation to draw the studs 62 outwards from the centre of the die
head and away from the work, whilst any relative rotative movements of the
parts a and d is prevented by reason of the feather keys a³, a formed on or
secured to the shank a¹ and engaging in correspondingly shaped recesses in the
sliding sleeve d.
c, care handles secured in the cam piece for operating it to rotate it by
hand, or in the rotation of the turret (to bring the successive cutting tools into
operative position) the projection or stem comes in contact with the slide or a
fixed part thereon, and in the continued movement of the turret this stem is
held, thus moving the cam ring relatively to the die holders and to the locking
sleeve, bringing all parts into position for operation on the work and locking
them so.
k, kare screws for securing the cutters in their holders b. The adjustment
of the depth of cut of the dies is effected by varying the positions of the inclines
or grooves e, e¹ relatively to the studs 62, and this change of position is effected
by releasing the screw nuts 6, 6, which are secured in the projecting ends of
bolts c, c. These bolts have heads which are countersunk into holes formed
in a crescent shaped plate 7, which plate is located in the groove in the
sleeve and the stems of these bolts thence pass through sleeved and through
the index plate m and out to receive the nuts c, c.
These bolts and nuts serve to clamp the three parts l, d and m tightly together
in their adjusted position, the adjustment being assisted by the position of the
index point m' relatively to the index graduations cut or mounted on the peri-
phery of the flanged part of d at a³.
By this arrangement of the crescent shaped plates, I obtain a broader base for
the bearing of the bolts, heads and nuts on the parts to be clamped.
In operation the die head having been placed in position in the hole in the
turret and the work having been brought up to the cutting dies, these dies
perform their function on the rotating rod, to be screwed, until the desired cut
has been completed, when a part on the travelling slide represented here by
the screwed stem A³, held in adjusted position by a lock screw Aº, comes in
contact with a stop (not shown) within base A on the bed A*, causes the motion
of the slide A2 to be arrested and thereby arresting the motion of the turret,
and consequently of the sleeve d, with the parts affixed to it, but by reason of
the hold of the cutters on the threads of the work, being screwed, and the con-
tinued rotation of that work the cutters, their holders b, the carrier and the
attached cam piece c continue to be moved forward, or to the left hand of the

page_text: drawings, until the extent of their movement relatively to the now arrested
sleeved, becomes sufficiently great to separate the eccentric end of the bolt
from its bolt hole 8, putting meanwhile the spring e in compression. As soon
as this bolt g is thus released the spring i is free to expand and to rotate the
stop piece and cause the cam ring c to be partially rotated, thereby drawing
outwards from the centre the lugs or studs and with them the attached
holders and cutters free from the work.
By these means I am enabled to dispense with the presence of any tripping
or stop mechanism for releasing the cutters from the work at the completion of
the cut, within the sleeve, or a tool proper, thereby leaving a perfectly free way
for any required length of screwed stem to pass therethrough, avoid the
inconvenience which arises from the clogging of such stop mechanism when so
internally placed, and also I can dispense with the holes usual for securing
such internal stop parts.
,, Figs. 11 and 12 are air holes, and serve to release the air pressure which
is caused by the locking of the tool or by the two parts coming together into
locked position, as at y y, which shows open or unlocked position of the tool.
2,2, Figs. 11 and 12 are dowel pin holes to secure the bolt heads and to pre-
vent the same from turning while the nuts are being turned to clamp the parts
together.
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. A die head for screw cutting in a lathe or screw cutting machine
characterized by its cutters, their holders a hollow skeleton carrier for the
holders, a spring actuated cam ring controlling the motions of those holders,
being mounted on a locking and releasing sleeve provided with a lock adapted
to engage and hold in adjusted position the cam ring and cutting and cutter
holding parts controlled by it, during cutting and as soon as the adjusted extent
of cut is complete, and the further movement of the slide in which the locking
parts are mounted is prevented by a stop, the cutter carrying holder and releas-
ing parts are carried forward for a limited distance against the pressure of a
spring, until the lock becomes disengaged therefrom and the cutting parts are
automatically released from the work.
2. In a die head such as described in Claim One, the combination therewith
of a locking means between the cam ring controlling the cutter holders and the
sleeve or main support characterized by the bolt being adjustable in either of
two temporarily fixed positions for the "roughing" and "finishing" cuts, respec-
tively without disturbance of the general adjustment of depth of cut, and by
such locking means being combined with a general adjustment capable of
instant actuation by simply loosening the nuts of holding bolts connecting
clamping plates which clamp the adjustable parts together."
3. The general arrangement and combination of the parts of a die head and
the method of operating the same for the purpose of automatically releasing the
cutters from the work as soon as an adjustable part on the slide of the machine
comes in contact with a stop, substantially as set forth.
Dated 20th, da.. T1000
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.