Improvements in Screw Cutting Turret Heads.
Year: 1889

page_text: Date of Application, 24th Sept., 1889-Accepted, 1st Feb., 1890
COMPLETE SPECIFICATION.
Improvements in Screw Cutting Turret Heads.
A communication from abroad by JAMES AMBROSE BEORER, of Mishawaka, St. Joseph,
County Indiana, in the United States of America, Machinist.
I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents, 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 turret machines for threading bolts in
which a turret or die carrier consisting of upper and lower opening and closing
halves or jaws, is provided with thread cutting dies or chasers arranged in sets at
proper intervals around its periphery, said jaws being provided with mechanism
whereby they may be moved at will, to open to release, or close to engage, the bolt
while the machine is in operation.
The object of the invention is to provide, in a single machine, means by which
various sizes and pitches of screws can be cut rapidly and without stopping the
machine.
This turret with die carrying jaws capable of opening and closing may be
stationary during operation and the bolt be caused to revolve or the bolt may be
fixed and the turret caused to revolve. The machines whereby the required rotary
motion is produced is common and well known.
Fig. 1 is a perspective view of turret mounted on lathic.
Fig. 2 is a perspective view of turret mounted on ways.
Fig. 3 is a longitudinal section through .
Fig. is a longitudinal section perpendicular to r―x.
Similar numbers refer to similar parts throughout the several views, in which
1 designates a tubular sleeve post (preferably of cast iron) secured by bolts or other
suitable devices to the proper portion of an ordinary lathe or screw cutting machine.
2 designates the upper of the opening and closing jaws of the turret (also preferably
of cast iron: 3 is its cap secured thereto by the countersunk screws 4, and 5 are its
screw cutting dies of variously predetermined sizes, preferably of an even number,
arranged in sets radially around its periphery and adjusted by the screws 6.
7 designates the lower of the opening and closing jaws of the turret (also preferably
of cast iron) arranged to slide on the sleeve post 1 and held in position by the guide
stop pins (preferably of steel) secured to upper turret jaw 2. 9 are its dies
corresponding with and directly opposite to the dies 5 of the upper turret jaw 2 and
are correspondingly arranged around its periphery and adjusted by the screw 10 and
adapted to co-operate with their corresponding and opposing dies 5 in the upper
turret jaw 211 is its cap secured by the countersunk screw 12.
The cross-piece 13 slides up and down only in the slots 14 and has its reduced
ends loosely inserted into the annular grooves 15 formed in the turret jaw cap 11.
The joint bolt 10 is secured thereto by the nut 17. The links 18 are pivoted at
their bottom ends to the bolts 16 by the pin 19, and at their top or upper ends to
the operating handle 20, by the pin 21, said operating handle 20 being pivoted to the
fulcrum 22 (by the pin 31), said fulcrum 22 being also arranged to slide a limited
distance in slot 24. This arrangement consitutes the opening and closing mechanism
of the invention.
The fulcrum 22 also has its reduced ends inserted in the annular groove 23, and
is held in its fixed diametrical position relative to the post 1 by the slots or
notches 24 formed thereon and is free to move up and down therein a limited
distance

page_text: A stop pin 25 is provided fitting the hole 26 formed in the turret cap 3 at the
same radial distance from its centre as the hole 27, formed in end of fülcrum 22 and
coinciding with the radial centre line of each of the pairs of dies 5 and 9 for the
purpose of permitting the turret to be rotated and maintaining it in a fixed position
whilst using any one pair of the series of dies in threading a bolt of corresponding
diameter. The reduced ends of the fulcrums 22 and 13 inserted in the annular
grooves 23 and 15, hold the upper and lower jaws of the turret in their proper
radial position and at the same time permit the simultaneous rotation of the upper
and lower turret jaws 2 and 7 and their attachments.
The upper and lower jaws 2 and 7 and their attachments are subject to a motion.
of translation along the turret sleeve 1, which, in the operation of closing or
advancing the jaws and their dies, is limited by the amount of end clearance of the
guide pin S from the plate 11, and in the reverse operation of opening or receding,
by the amount of eccentricity or throw of the band lever 20, the amount of throw
being equally divided between both upper and lower jaws 2 and 7 and adjusted by
the clearance between the bottom jaw plato 11 and the collar of turret post 1, the
hand lever being permitted to drop a portion of its swing till contact is obtained
between the lower turret.jaw plate 11 and post collar 1. The remaining portion of
the throw is taken up by the springs 28, thus raising the upper jaw 2 and relieving
or disengaging the dies 5 and 9 from the bolt operated upon. The operation of the
attachment is as follows: When it is desired to thread a revolving bolt of a diameter
corresponding with one of the pairs of the series of dies the stop pin 25 is removed
and the turret is revolved till the pair of dies suited to the blank or rod to be
threaded are in their working position opposite the bolt; the stop pin is reinserted
into the holes 26 and 27, thus maintaining the turret in position. The blank or rod
is rotated at a suitable velocity by means of any convenient rotating head by which
it is held, the said head being secured to a lathe or scrow machine spindle. The
turret upper and lower jaws 2 and 7 are closed till the guide pins contact with the
cap 11 by means of the operating handle 20 and its toggles IS, thus bringing the
upper and lower dies 5 and 9 into their proper threading position, and consequently
the same radial distance apart from the centre of the bolt operated upon, in which
position the entire turret jaws 2 and 7 are suspended by the fulcrums 22, resting
and held in position by the notches 24 on post 1. The carriage carrying the
turret is moved or fed to and along the blank till the requisite length of its surface
is threaded the operating handle is dropped into its horizontal position, thus
opening the dies and permitting the turret to be withdrawn without reversing the
rotation or stopping the machine, and at the same time permitting a free exit of the
cuttings through the radial channel or groove 29 on a line with the cutting dies.
It is obvious that, no matter what the size of the blank to be threaded, the operation
can be performed without loss of time in stopping the machine by simply rotating
the turret in the manner hereinbefore described, and bringing the proper dies into
operation. Grooves 29 formed on the inner surface of the upper and lower turret.
jaws 2 and 7 and the opening 30 formed in the turret post I are provided for the
purpose of permitting a long bolt to pass through and between the turret jaws and
post whilst being threaded.
It is obvious that an upper and a lower single cutting tool such as is used in the
ordinary screw cutting lathe may be substituted for the threading dies hereinbefore
described without departing from the spirit of the invention. If such cutting tools
are used the turret carriage must be provided with a self acting feed screw or other
suitable device, such as is used in the ordinary screw cutting machine.
It is sometimes desirable to mount the turret on a revolving spindle or mandril
and hold the bolt fixed. This does not involve any change in the invention but only
additional parts whereby the jaws may be opened or closed while the turret is in
revolution around the axis of one or another of its threading dies. That additional
mechanism will now be described, the structure of the turret being unchanged. In
this case the tubular turret sleeve post 1 and its supporting mechanisin is mounted

page_text: by means of an angle plate 32, as shown in Fig. 1, upon the face plate 33 of an
ordinary lathe, the axis of the turret post and the axis of the lathe being in exact
intersection.
The operating handle 20 is made short because there is no occasion for touching
it with the hand and it is provided with a rod 34 which extends from its connection
with said handle 20 in a direction parallel or thereabouts with the axis of the lathe
and at its outer extremity it is jointed to a clutch collar 35 which is adapted to slide
on the lathe spindle or some part co-incident therewith, and be controlled by an
ordinary forked clutch lever. An endwise movement of said 34 moves the handle 20
and the links 18 to effect the movement of the turret jaws precisely as though moved
by the hand applied directly to tlie handle 20, and as will be readily understood this
movement can be effected as readily while the turret is revolving with the latho
spindle as while at rest.
When the turret is adapted to be mounted on the spindle of a lathe it will be
desirable to prevent the stop bolt 25 from being thrown out by the rotation of
the turret and said pin may then be provided with the case 36 and retaining
spring 37.
It is known that previous to the present invention turrets without movable jaws
but having various sizes of threading dies arranged around their peripheries, have
been used in connection with screw cutting machines, and such a combination is
therefore not claimed broadly, but,
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1st. In a screw cutting turret head, the combination of a turret post with its upper
and lower opening and closing turret jaws and their cutting dies arranged around
their peripheries and mechanism for operating the said jaws, substantially as and for
the purpose described.
2nd. In a screw cutting turret head, the combination of a turret post with its upper
and lower opening and closing turret jaws and their corresponding pairs of dies
adjustably secured around their peripheries, substantially as and for the purpose
described.
3rd. In a screw cutting turret head, the combination of the receding and
approaching turret jaws mounted and moving freely on a suitable supporting post,
with their corresponding pairs of cutting dios arranged around their peripheries and
having their cutting faces turned inwardly, substantially as and for the purpose
described.
4th. In a screw cutting turret head, the combination of an upper receding and
approaching turret jaw with a similar lower turret jaw mounted and adapted to
rotate on a suitable post, said upper and lower jaws having radial grooves formed on
their inner surfaces coincident with radial centres of cutting dies, substantially as and
for the purpose described.
5th. In a screw cutting turret head, the upper and the lower receding and approaching
turret jaws mounted and adapted to rotate on a suitable post, said jaws having radial
grooves formed on their inner surfaces and arranged in opposite pairs to coincide
with openings formed in turret post in line of centres of cutting faces of dies,
substantially as and for the purpose described.
6th. In a screw cutting turret head, the combination of an upper receding and
approaching turret jaw and its guide pins secured perpendicularly to its inner
surface, with a lower receding and approaching turret jaw, the latter being provided
with guide holes formed therein to loosely receive said guide pins, substantially as
and for the purpose described.
7th. In a screw cutting turret head, the combination of an upper receding and
advancing turret jaw and its guide pins secured perpendicularly to its inner surface
with a similar lower turret jaw provided with guide holes to freely receive said guide

page_text: pins, said jaws arranged to be rotated simultaneously, substantially as and for the
purpose described.
8th. In a screw cutting turret head of the character described, the combination of
an upper turret jaw and its cap secured thereto, and an upper cross-head arranged
to slide, in guides formed in turret post and having its projecting ends inserted into
an annular groove formed between the surfaces of the said turret jaw and its cap,
with a lower turret jaw, cap and cross-head of like construction and toggle links
connecting said cross-heads for opening and closing said jaws, substantially as and
or the purpose described.
9th. In a screw cutting turret head, the combination of an upper receding and
advancing turret jaw and a lower receding and advancing turret jaw with their
expanding springs contacting witli inner surfaces of said jaws, substantially as and
for the purpose described.
10th. In a screw cutting turret head, the combination with turret posts, the
turret jaws and their cross-heads of the character described of an interchangeable
stop pin arranged to be inserted into stop holes formed in top turret cap and top
cross head, substantially as and for the purpose described.
11th. In a screw cutting turret head of the character described, the combination
with the post 1, fulcrum 22, carrying turret cap 3, and its upper disengaging jaw 2,
having adjustable dies 5 arranged around its periphery and adjusted by the screws 6,
of the lower disengaging turret jaw 7 and its cap 11, said jaw 7 having adjustable
.dies 9 arranged around its periphery, and adjusted by screws 10, and means
for opening and closing the jaws, substantially as and for the purpose described.
12th. In a screw cutting turret head, the combination with the upper disengaging
turret jaw 2 and its cap 3 mounted on post 1, and having the guide pin 8 secured
thereto and their springs 28 encircling said pins of the lower disengaging turret jaw 7
and its cap 11, said jaw provided with holes to loosely receive said guide pins and
limited in its motion by its cap 11, connecting with end of said guide pins, sub-
stantially as and for the purpose described.
13th. In a screw cutting turret head, the combination of the turret post and its
upper and lower disengaging jaws with the cross piece sliding in the slots 14 and
having its ends inserted in the annular groove 15, the links 18 hinged to bolt 16 by
the pin 19 on their lower ends, and on their upper ends to the bandle 20 by the
pin 21 and handle fulcrumed by the pin 31 to the fulcrum 22 sliding in notches 24
formed on the turret post 1, and having its ends inserted in grooves 23 formed on
cap 11, all substantially as and for the purpose described.
Dated this 24th day of September 1889.
PHILIP M. JUSTICE.