IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING SCREW THREADS
Year: 1882

page_text: "
LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in the
County of Middlesex Gentleman for an invention of "IMPROVEMENTS IN
MACHINERY OR APPARATUS FOR CUTTING SCREW THREADS Communicated
to him from abroad by William Dunderdale Forbes of Bridgeport in the State
of Connecticut United States of America
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 26th May 1882.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING SCREW
THREADS" A Communication to me from abroad by William Dunderdale Forbes
of Bridgeport in the State of Connecticut United States of America
The object of this Invention is to make a Screw cutting tool instrument or
apparatus which can be used to advantage and with facility for cutting screw
threads on pipes rods etc of large diameter.
For this purpose a Cylindrical casing is provided with a hub into which and
the casing is introduced the pipe or like article to be threaded or have Screw.
thread cut upon it the pipe being secured to the said hub by set screws or other
convenient means.
A die carrying ring is provided threaded externally and adapted to the internal
screw thread of the said casing and has teeth on its periphery the screw thread
being cut into these teeth An elongated pinion having teeth adapted to those on
the periphery of the said ring is contained within a suitable formed chamber
formed on the cylindrical casing the journals of the pinion having bearings in the
ends of the said chamber while one of the Journals extends beyond the casing for
receiving a suitable handle.
A threading die which may be made either in the form of a continuous ring
with screw cutting projections or in segmental sections is held in the die-carrying
ring by and between an internal flange in the same and a cap which is screwed
into the ring the cap being serrated externally so that it can be firmly grasped
CD 11

page_text: by the hands when it has to be screwed tight or being otherwise prepared to
receive a suitable instrument by which it can be easily turned The die is prevented
from turning in the ring by projections on one and recesses in the other or by any
other appropriate device.
It will be understood that the pitch of the screw thread on the die holding ring
must necessarily be the same as that of the screw cutting dies.
Supposing the pipe or rod to be operated upon to have been introduced into the
casing and its hub above referred to its end bearing against the threading die or
dies the pinion is turned so as to rotate the ring and in rotating the same must
necessarily traverse the interior of the casing to an extent during each revolution
determined by the pitch of the thread the dies conséquently cutting on the pipe
or rod a thread corresponding in pitch with that of the thread on the ring.
Within the casing there is a hollow cylindrical projection on which the die
holding ring fits snugly, but so as to slide freely this projection serving as a shield
to prevent the metal cuttings due to the threading of the pipe from gaining access
to the threaded interior of the casing as the die carrying ring traverses within the
same. In like manner the flange of the screw cap as it overhangs the casing
prevents the cuttings from gaining access to the thread of the same the shields in
both cases preventing obstructions of the thread and permitting the die carrying
ring to freely enter and to be as freely withdrawn from the casing According to
a convenient modification the die carrying ring has teeth on its periphery but
instead of cutting the screw thread on the teeth it is cut in the interior of the ring
a corresponding thread being cut on the cylindrical projection within the casing
The plan first described is however preferable as in the tool or apparatus last
alluded to the cuttings from the pipe or rod can gain access to the threaded interior
of the ring.
According to another modification the lead screw on the die carrying ring and
outer casing is dispensed with a lever being hung to the casing and the short arm
of this lever acting on the die carrying ring to press the dies on to the end of the
pipe until several threads have been cut thereon when the ring is released from
the control of the lever the threads which have been cut serving as lead threads
to guide the dies in continuing the operation.
In another arrangement the rotating die carrying ring is dispensed with the
die being adapted to a pocket in the casing and the pipe being carried by a ring
which is toothed on the periphery for adaptation to an elongated pinion and has
a threaded hub adapted to a lead screw in the casing Or the arrangement may be
further modified in which the dies are carried by a rotating ring but in this case
the ring is actuated by a worm wheel and has no longitudinal movement the pipe
being carried by a sliding frame to the end of which is swivelled a ring threaded
for adaptation to a lead screw on the holding ring D-When the thread is being
cut this ring is locked to the framing by a spring pin but when it is desired to
rotate the said ring without imparting any longitudinal movement to the frame
the pin is withdrawn so as to release the auxiliary ring from the frame so as to
permit the said ring to turn with the aforesaid holding ring-This is resorted to
when it is desired to cut the pipe in which case a cutting tool is adapted to a recess
in the latter ring a threaded opening in the tool receiving a screw stem having a
head which is operated by a pin introduced through an opening in the cover plate
of the said ring.
In this apparatus the dies are furnished at the rear ends with rounded heads
adapted to rounded recesses in the holding ring these dies bearing on abutments
when the ring is turned forward but being free to swing upwards when the ring
is turned backwards-In this case the pipe is free from the control of the dies and
can be removed longitudinally from the apparatus.
After the removal of the pipe the dies may be restored to position for acting on
a new pipe by partially turning the cover plate and its pins acting on the dies the
cover plate being slotted where the confining screws pass through the same so that
the necessary movement of said plate is permitted,

page_text: According to a modification of this die and die holder the holding ring has for
each die two rounded openings the die facing in one direction and being adapted
to one opening when the tool is constructed for cutting right hand threads but
facing in the opposite direction and being adapted to the other opening when the
tool is intended for cutting left hand threads-In this modification also an
additional bearing abutment is provided.
The means for securing the pipe or rod to be operated upon to the framing
comprise a pair of jaws guided in slots in the former and each having a threaded
opening to which is adapted a screw journaled in the framing
Each screw has a pinion and to these pinions are adapted spring pawls carried
by rings at the ends of a yoke the rings being journaled on the stems of the screws
and the yoke having a handle so that by vibrating this yoke the pinions and screws
will be operated and the jaws tightened on the pipe or rod
Each aforesaid pawl consists of a cylindrical block adapted to an opening in the
ring and free to slide therein radially to a limited extent under control of the
spring.
The inner end of the cylindrical block has a bevelled rib adapted to the teeth of
the before mentioned pinion and the outer end has a handled stem projecting
through the ring last referred to so that by grasping this stem the block can be
withdrawn radially until its rib is clear of the teeth of the said pinion the block
being then reversed and allowed to again spring into place whereupon on again
vibrating the yoke the screws will be turned in the opposite direction and the
holdings jaws retracted.
The same principle may be applied to a tool for turning the operation pinion or
for other similar purposes.-The ring in this case instead of forming part of a yoke
has a projecting handle or handles and the pinion bas a central angular opening and
is confined laterally to the said ring by a cap.
According to another arrangement of the apparatus, the die carrying ring has
two lead screws, the one screw being righthanded, and the other lefthanded. The .
flange of the cylindrical casing in this case is adapted for the reception of nuts
adapted to either of the lead screws, so that either right or lefthand threads can be
cut upon the pipe or rod thus the dies will consequently cut a righthandthread
upon the pipe but by removing the nut; and substituting another therefor, adapted
to engage with the lead screw, the dies upon the rotation of the holdingring will
cut a lefthand thread upon the pipe or rod.
My improved screw cutting tool instruments or apparatus is well adapted to the
threading of largepipes such as are used for oilwells, owing to the facility with
which the die carrying ring or pipe carrying frame can be rotated by turning the
pinion
Another advantage is the operation without any necessity for griping the pipe in
a vice or other retaining device for the threading of the pipe may be accomplished
while it is simply resting on any support which may be at hand.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
25th November 1882.
"6
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman 'IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING SCREW
THREADS" a communication to me from abroad by William Dunderdale Forbes
of Bridgeport in the State of Connecticut United States of America
The object of this Invention is to make a screw-cutting instrument which can be
used to advantage and with facility in cutting screw threads on pipes rods and the
like of large diameter.
And in Order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figure 1 is a front view partly in section of one form of the instrument.
Figure 2 a longitudinal section on the line 1. 2 Figure 1.
Figure 3 a detached view of part of Figure 1.
Figure 4 an exaggerated perspective view of part of the instrument,
Figure 5 a sectional view of a modified form of instrument,
Figure 6 a sectional view of another modification
Figure 7 a section of a further modification.
Figure 8 an end view of the same.
Figure 9 a sectional view of a modified instrument of the same class as that
shewn in Figures 7 and 8.
Figures 10 and 11. views of the opposite ends of the instrument shewn in
Figure 9.
Figure 12 a view of part of the instrument Figure 9 constructed for either right
or left hand cutting.
Figure 13 a section of an instrument adapted for cutting either right or left
hand threads.
Figure 14 an end view partly in section of a ratchet lever adapted for use in
connection with the instruments and
Figure 15 a perspective view of part of said lever
I will first describe the instrument shown in Figures 1. 2. 3 and 4
A is a cylindrical casing provided with a hub a into which and into the casing
is introduced (as indicated by dotted lines in Figure 2) the pipe x to be threaded
the said pipe being secured to the hub by set screws w or otherwise.
The die-carrying ring D is threaded externally and adapted to the internal screw
thread of the casing A and has teeth on its periphery as shewn in Figure 1 the
screw thread being cut into these teeth as best observed in the edge view Figure 4.
An elongated pinion B (an external longitudinal view of which is shown in
Figure 3) having teeth adapted to those on the periphery of the ring D is contained
within a chamber in a projection b of the casing A the journals of the pinion
having bearings in the ends of the said projection as shown in Figure 2 and
one of the journals extending beyond the casing as at y for receiving a suitable
handle.
The threading-die E which may be made either in the form of a continuous ring
with screw-cutting projections e or in segmental sections, is held in the ring D
by and between an internal flange f in the same and'a cap G which is screwed
into the ring the said cap being serrated externally so that it can be firmly
grasped by the hands when it has to be screwed tight or being otherwise formed
to receive a suitable instrument by which it can be easily turned The die is
prevented from turning in the ring by projections on one and recesses in the other
or by any other appropriate device.
It will be understood that the pitch of the screw-thread on the die-bolding ring
must necessarily be the same as that of the screw-cutting dies.

page_text: Supposing the pipe x to have been introduced into the casing A and its hub a
as shown by dotted lines in Figure 2 its end bearing against the die or dies E the
pinion B is turned so as to rotate the ring and in rotating the ring must necessarily
traverse the interior of the casing to an extent during each revolution determined
by the pitch of the thread the dies consequently cutting on the pipe x a thread
corresponding in pitch with that of the thread on the ring.
There is within the casing a hollow cylindrical projection m on which the die
holding ring D fits snugly but so as to slide freely this projection serving as a shield
to prevent the metal cuttings made during the threading of the pipe from gaining
access to the threaded interior of the casing as the die carrying ring traverses
within the same. In like manner the flange p of the screw cap G as it overhangs
the casing prevents the cuttings from gaining access to the thread of the same the
shields in both cases preventing obstructions of the thread and permitting the
die-carrying ring to freely enter and to be as freely withdrawn from the casing.
In the modification shewn in Figure 5 the die-carrying ring D has teeth on its
periphery as before described but instead of cutting the screw-thread on the teeth
it is cut in the interior of the ring a corresponding thread being cut on the
cylindrical projection m
The plan first described is however preferable as in the instrument shewn in
Figure 5 the threaded interior of the ring is exposed to the cuttings from the pipe.
In the modification shown in Figure 6 the lead screw on the die-carrying ring
and outer casing is dispensed with a lever P being hung to the casing and the
short arm of this lever acting on the die-carrying ring to press the dies on to the
end of the pipe until several threads have been cut thereon when the ring is
released from the control of the lever the threads which have been cut serving as
lead threads to guide the dies in continuing the operation.
In the modification shewn in Figures 7 and 8 the rotating die-carrying ring is
dispensed with the die being adapted to a pocket in the casing A and the pipe
being carried by a ring which is toothed on the periphery for adaptation to an
elongated pinion and has a threaded hub adapted to a lead screw in the casing,
Figures 9. 10 and 11 show a modification in which the dies are carried by a
rotating ring D but in this case the ring is actuated by a worm wheel B' and has
no longitudinal movement the pipe being carried by a sliding frame J to the end
of which is swivelled a ring s threaded for adaptation to a lead screw on the ring D
When the thread is being cut this ring is locked to the frame J by a spring pin t
but when it is desired to rotate the ring D without imparting any longitudinal
movement to the frame J the pin is withdrawn so as to release the rings from the
frame and permit the said rings to turn with the ring D This is resorted to
when it is desired to cut the pipe in which case a cutting tool q is adapted to a
recess in the ring a threaded opening in the tool receiving a screw stem r having
a head which is operated by a pin introduced through an opening in the cover
plate H of the ring D
In this instrument the dies e are furnished at the rear ends with rounded heads w
adapted to rounded recesses in the ring D these dies bearing on abutments w¹ when
the ring is turned forward but being free to swing upward in the direction of the
arrows when the ring D is turned backward In this case the pipe is free from the
control of the dies and can be removed longitudinally from the instrument
After the removal of the pipe the dies may be restored to position for acting on
a new pipe by partially turning the cover plate H, pins c on the latter acting on
the dies and the cover plate being slotted where the confining screws pass through
the same so that the necessary movement of the said plate is permitted
In Figure 12 is shewn a modification of this die and die holder the ring D having
for each die two rounded openings the die facing in one direction and being
adapted to one opening when the tool is constructed for cutting right hand threads
but facing in the opposite direction and being adapted to the other opening when
the tool is intended for cutting left hand threads. In this modification also an
additional abutment w³ is provided.

page_text: The means for securing the pipe to the frame J comprise a pair of jaws K guided
in slots in the frame and each having a threaded opening to which is adapted a
screw k journalled in the frame J
Each screw has a pinion g and to these pinions are adapted spring pawls carried
by rings i at the ends of a yoke L the rings being journalled on the stems of the
screws k and the yoke having a handle L' so that by vibrating this yoke the pinions
and screws will be operated and the jaws tightened on the pipe
Each pawl consists of a cylindrical block adapted to an opening in the ring i and
free to slide therein radially to a limited extent under control of the spring-The
inner end of the said cylindrical block has a bevelled rib h' adapted to the teeth of
the pinion g and the outer end has a handled stem h² projecting through the ring i
so that by grasping this stem the block can be withdrawn radially until its rib ¹
is clear of the teeth of the pinion g the block being then reversed and allowed to
again spring into place whereupon on again vibrating the yoke the screws k will
be turned in the opposite direction and the jaws K retracted
The same principal may be applied to a tool for turning the operating pinion B
or for other purposes such a tool being shewn in Figures 14 and 15 The ring i in
this case instead of forming part of a yoke has a projecting handle or handles ¿¹
and the pinion g has a central angular opening and is confined laterally to the
ring i by a cap i³
In the instrument shown in Figure 13 the die carrying ring D has two lead
screws the screw M being right handed and the screw N left handed-The flange m
of the casing A in this case is adapted for the reception of nuts adapted to either of
the lead screws so that either right or left hand threads can be cut upon the pipe.
Thus as shown by full lines in Figure 13 the nut is adapted to the lead screw M
and the dies will consequently eut a right hand thread upon the pipe but by removing
the nut and substituting therefor a nut such as is shown by dotted lines adapted
to engage with the lead screw N the dies upon the rotation of the ring D will cut
a left hand thread upon the pipe.
The improved screw cutting instruments are well adapted to the threading of
large pipes such as are used for oil wells owing to the facility with which the die
carrying ring or pipe carrying frame can be rotated by turning the pinion. Another
advantage is the operation without any necessity for gripping the pipe in a vice or
other retaining device for the threading of the pipe may be accomplished while it
is simply resting on any support which may be at hand
The instruments may be used for the threading of rods of large diameter as well
as pipes
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is-
.
The combination in die stocks of the following elements namely first a casing A
adapted to be secured to the object to be threaded second a threaded die-carrying
ring having teeth on its periphery and a screw thread adapted to a corresponding
thread in the casing and third an elongated pinion having teeth adapted to those
of the die-carrying ring all substantially as set forth-Also the various arrange-
ments or modifications of the apparatus hereinbefore described with reference to
the several figures of the accompanying Drawings
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this twenty fourth day of November One
thousand eight hundred and eighty two
J. HENRY JOHNSON (L.S.)