Improvements in Taps for Use in Forming Screw-threads in Articles or Objects being Operated upon in Lathes or Screwing Machines or other Machines.
Year: 1897

page_text: Date of Application, 3rd July, 1897
Complete Specification Left, 4th Apr., 1898-Accepted, 2nd July,
1898
Improvements in Taps for Use in Forming Screw-threads in
Articles or Objects being Operated upon in Lathes or Screwing
Machines or other Machines.
I, RICHARD KILBURN, of 138, Church Lane, Gorton, Manchester, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention consists in improvements in taps for use in forming screw-threads in
articles or objects being operated upon in lathes or screwing machines or other
machines.
The principal object of my invention is the provision of taps which can be released
and withdrawn from the threads formed by means of them without being unscrewed
from such screw-threads and shall be efficient, simple in construction and cheap to
maintain in working condition.
According to my invention, I provide in the construction of a tap, two or more dies
or cutters mounted in a holder and capable of being slidden or moved therein, so as
to be capable of being moved into and out of position to form screw-threads in the
articles or objects to be operated upon. The holder in which the said dies or cutters
are mounted is arranged so as to be capable of being slidden lengthwise in or upon a
socket capable of being mounted in the lathe or screwing machine or other machine
in which the tap is to be employed, and the said holder may in some cases be
arranged to be capable of being turned to some extent in relation to the said socket
as well as of being moved longitudinally therein or thereon. In conjunction with the
said dies or cutters, a spring or springs is or are provided to move the said dies or
cutters out of the position which they occupy when forining screw-threads in the
articles or objects to be operated upon. A separate spring may be provided in
conjunction with each die or cutter, or one spring may be arranged to act in con-
junction with two or more dies or cutters and if, as is convenient in the construction
of a tap of comparatively small size, two dies or cutters capable of being moved or
slidden transversely in the holder in which they are mounted be employed, the spring
employed to move such dies or cutters out of position to form screw-threads in articles
or objects, may conveniently be placed between the said dies or cutters and arranged
to act upon both of them. In order that the said dies or cutters may be moved into
position to forn screw-threads in the articles or objects to be operated upon, I provide
a rod or support or two or more rods or supports connected together or arranged to be
moved by the same or similar means, and arrange such rod or support or rods or
supports so that it or they shall be capable of being moved lengthwise in the socket
above mentioned. The said rod or support or rods or supports may, in any case in
which it may be preferable to so arrange it or them, be arranged so as to be capable
of being caused to turn about its or their own axis or axes or about the axis or centre-
line of the tap. The said rod or support or rods or supports is or are arranged to act
when moved in one way upon the said dies or cutters by means of inclined or other
suitably shaped parts formed upon such rod or support or rods or supports or upon

page_text: the dies or cutters, or other suitable means so as to move such dies or cutters against
the force exerted upon then by the spring or springs employed in conjunction there-
with. In order that when moved into position to form screw-threads in articles or
objects to be operated upon by the tap, the said dies or cutters may be held in such
position, I provide upon such dies or cutters or upon the rod or support or rods or
supports used therewith, or both upon such dies or cutters and the said rod or support
or rods or supports, parts which are so formed that serving as means by which the
said dies or cutters may bear against the said rod or support or rods or supports, they
shall prevent the spring or springs above mentioned or pressure exerted upon the
cutting edges or parts of the dies or cutters and tending to force such dies or cutters
out of position to form screw-threads in articles or objects, from having any tendency
to move the said rod or support or rods or supports in relation to such dies or cutters.
The inclined faces or other suitably shaped parts or other means by which the said
rod or support or rods or supports acts or act upon the dies or cutters above mentioned
in moving them into position to form screw-threads in the articles or objects to be
operated upon, are so formed that they serve also as means by which the springs
aforesaid, in moving the said dies or cutters out of the position which they occupy
when in use in forming screw-threads, may move the said rod or support or rods or
supports, if the said dies or cutters or the said rod or support or rods or supports or
both such dies or cutters and rod or support or rods or supports be moved so that the
parts of such dies or cutters and rod or support or rods or supports, which are in
contact when such dies or cutters are in position to form screw-threads in articles or
objects to be operated upon, are no longer in contact. A collar capable of being
slidden or turned upon the socket above mentioned and connected or caused to act
in any suitable manner to or upon the rod or support or rods or supports above men-
tioned or any other suitable means may be provided to enable such rod or support or
rods or supports to be moved in order that the dies or cutters may be brought into
and held in position to form a screw-thread in an article or object to be operated
upon.
When a tap constructed according to my invention is screwed into a hole in an
article or object to be operated upon so as to form a screw-thread therein, and
the longitudinal movement of such tap in relation to such article or object or
the movement of such article or object in relation to such tap or the relative
movement of both such tap and article or object is arrested by a previously moving
part or previously moving parts arriving against a suitable stop or stops, the dies or
cutters of the tap continuing to screw themselves into the said article or object will
move the holder in which they are mounted in relation to the socket aforesaid so as
to move out of contact with the rod or support or rod or supports aforesaid, the parts
by which the dies or cutters when in position to form screw-threads in an article or
object to be operated upon bear, against such rod or support or rods or supports, and
when the said holder has been so moved the spring or springs above mentioned
moving the said dies or cutters will cause such dies or cutters to be disengaged from
the screw-thread which they have formed in the said article or object, so that the tap
may be withdrawn from or have removed from it the said article or object without
any unscrewing of such tap or article or object being requisite. In moving the said
dies or cutters so as to disengage them from the screw-thread which they have
formed in an article or object operated upon by such dies or cutters the spring or
springs aforesaid will move the abovementioned rod or support or rods or supports in
a direction opposite to that in which it or they was or were moved in placing the
said dies or cutters in position to form a screw-thread in such article or object and
in order that the said spring or springs may more easily move the said rod or
support or rods or supports in such direction, preferably provide a spring or
springs to assist such spring or springs aforesaid in so moving such rod or sup-
port or rods or supports. After the tap has been removed from the article or
object, in which a screw-thread has been formed thereby, or after the article or
object in which a screw-thread has been formed has been removed from such tap, the
dies or cutters of such tap are replaced in position to form a screw-thread by the

page_text: holder in which they are mounted and the rod or support or rods or supports above
mentioned being moved in directions opposite to those in which they were moved in
order that the dies or cutters might be disengaged from the article or object in which
a screw-thread was formed thereby. The rod or support or rods or supports above
mentioned may be and is or are preferably so formed that besides embracing or
bearing against the dies or cutters of the tap in holding them in position to form
screw-threads in articles or objects to be operated upon, it or they shall bear against
the holder in which such dies or cutters are mounted and so support and protect such
dies or cutters from injury.
Taps constructed according to my invention may be so constructed as to be capable
of being used to first partially form a screw-thread in an article or object operated
upon thereby and then to complete the formnation of a screw-thread therein. The
arrangements and apparatus employed to enable the dies or cutters of taps constructed
according to my invention to be used first to partially form a screw-thread in an
article or object and then to complete the formation of a screw-thread therein will
necessarily be different in different cases according to the manner in which the dies
or cutters employed in the taps are constructed and arranged.
In one mode of enabling a tap constructed according to my invention to be used
first to partially form a screw-thread in each article or object operated upon thereby
and then to complete the formation of a screw-thread therein, I arrange the rod or
support or rods or supports employed in the tap so that it or they may be turned
about its or their own axis or axes or the axis or centre-line of the tap as well as
inoved longitudinally therein or arrange the holder in which the dies or cutters of the
tap are mounted so that it may be turned as well as moved longitudinally in relation
to the socket on or in which it is mounted and form the rod or support or rods or
supports or the dies or cutters or both the rod or support or rods or supports and the
dies or cutters with parts so shaped that by changes being made in the relative
positions of such rod or support or rods or supports and dies or cutters, the dies or
cutters may be set in position either to partially form or to completely form screw.
threads in the articles or objects operated upon. A scale and index or other device
or devices of any suitable kind may be provided to, indicate the different relative
positions of the said dies or cutters and rod or support or rods or supports and a
detent capable of sliding in a groove or grooves or other suitable device may be
provided to retain the dies or cutters and rod or support or rods or supports in any
relative positions in which it may be necessary or desirable to retain them. The
turning of the said rod or support or rods or supports or holder may be effected by
any suitable means such as by a finger or collar being formed on or connected to such
rod or support or rods or supports or holder and arranged in any convenient position
in or upon the tap so as to be readily moved as may be necessary or desirable from
time to time by the person using the tap.
In another mode of enabling a tap constructed according to my invention to be
used first to partially form a screw-thread in each article or object operated upon
thereby and then to complete the formation of a screw-thread therein, the rod or
support or rods or supports employed in the tap may be provided with movable parts
capable of being moved laterally or longitudinally in relation to the other parts
thereof, so that the dies or cutters with which the said rod or support or rods or
supports is or are employed may be moved and held thereby into and in different
positions from time to time and the movement of the said movable part or parts of
the said rod or support or rods or supports may be effected by any suitable means
operated by means of a finger or collar or other suitable device or devices provided
in any convenient position or positions in or upon the tap and connected to a
filling piece or filling pieces or cam or cams or wedge or wedges or other suitable
device or devices capable of being used to move or modify the position of the said
movable parts of the rod or support or rods or supports aforesaid in relation to the
other parts thereof.
In another mode of enabling a tap constructed according to my invention to be
used first to partially form a screw-thread in each article or object operated upon

page_text: thereby and then to complete the formation of a screw-thread therein, besides
employing in a tap a rod or support or rods or supports provided with movable parts
capable of being moved so as to modify the positions of the dies or cutters with
which they are used and providing means to move such movable parts, I construct
the holder in which the dies or cutters of the tap are mounted so that a part or parts
of it may be moved in relation to the other part or parts either by the means pro-
vided to move or modify the positions occupied by the movable part or parts of the
said rod or support or rods or supports or by any other suitable means.
In another node of enabling a tap constructed according to this part of my inven-
tion to be used first to partially form a screw-thread in each article or object operated
upon thereby and then to complete the formation of a screw-thread therein, the dies
or cutters employed in the tap are provided with parts capable of being moved into
and secured by means of wedges or filling pieces or other suitable means operated
in any suitable way, in different positions in relation to the parts upon which such
parts are mounted.
In another mode of enabling a tap constructed according to my invention to be
used first to partially form a screw-thread in each article or object operated upon
thereby and then to complete the formation of a screw-thread therein, which is
applicable to a tap in which one rod or support is employed in conjunction with two
dies or cutters capable of being slidden transversely in the holder in which they are
mounted, the rod or support employed in the tap is made capable of being turned in
the interior of the tap as well as moved longitudinally therein and so made capable
of moving the dies or cutters with which it is employed into and holding them in
different positions as may be necessary or desirable from time to time. The turning
of the said rod or support may be effected by any suitable means such as by a finger
or collar being formed on or connected to such rod or support and arranged in any
convenient position in or upon the tap so as to be readily moved as may be desirable
from time to time. A scale and index or other suitable device to indicate the
position of the dies or cutters and any suitable detent or other device or devices to
retain the dies or cutters in any position in which they may be placed may be
provided.
Taps constructed according to my invention may be arranged to form single-
threaded or double-threaded or other screws in the articles or objects operated upon
thereby.
The dies employed in a tap constructed according to my invention may be arranged
so as to be readily replaced by others so that holes of different diameters may be
tapped or formed with screw-threads or so that screw-threads of different pitches
may be formed at different times in the articles or objects operated upon by such
tap.
Dated in Canne
11007
Improvements in Taps for Use in Forming Screw-threads in
Articles or Objects being Operated upon in Lathes or Screwing 4
Machines or other Machines.
I, RICHARD KILBURN, of High Bank, Gorton, Manchester, in the County of
Lancaster, formerly of 138, Church Lane, Gorton, Manchester, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention and in what

page_text: manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
My invention consists in improvements in taps for use in forming screw-threads in
articles or objects being operated upon in lathes or screwing machines or other
machines.
The principal object of my invention is the provision of taps which can be released
and withdrawn from the threads formed by means of them without being unscrewed
from such screw-threads and shall be efficient, simple in construction, and cheap to
maintain in working condition.
In
According to my invention, I provide in the construction of a tap, two or more
dies or cutters mounted in a holder and capable of being slidden or moved therein,
so as to be capable of being moved into and out of position to form screw-threads in
the articles or objects to be operated upon. The holder in which the said dies or
cutters are mounted is arranged so as to be capable of being slidden lengthwise in or
upon a socket capable of being mounted in the lathe or screwing machine or other
machine in which the tap is to be employed. In conjunction with the said dies or
cutters, a spring or springs is or are provided to move the said dies or cutters out of
the position which they occupy when forming serew-threads in the articles or objects
to be operated upon. A separate spring may be provided in conjunction with each
die or cutter, or one spring may be arranged to act in conjunction with two or more
dies or cutters and if, as is convenient in the construction of a tap of comparatively
small size, two dies or cutters capable of being moved or slidden transversely in the
holder in which they are mounted, be employed, the spring employed to move such
dies or cutters out of position to form screw-threads in articles or objects, may
conveniently be placed between the said dies or cutters and arranged to act upon
both of them. In order that the said dies or cutters may be moved into position to
form screw-threads in the articles or objects to be operated upon, I provide a rod or
support, and arrange such rod or support so that it shall be capable of being moved
lengthwise in the socket above mentioned. The said rod or support is arranged to
act when moved in one way upon the said dies or cutters by means of inclined or
other suitably shaped parts formed upon such rod or support or upon the dies or
cutters, or other suitable means, so as to move such dies or cutters against the force
exerted upon them by the spring or springs employed in conjunction therewith.
order that when moved into position to form screw-threads in articles or objects to be
operated upon by the tap, the said dies or cutters may be held in such position, I
provide upon such dies or cutters or upon the rod or support used therewith, or both
upon such dies or cutters and the said rod or support, parts which are so formed that
serving as means by which the said dies or cutters may bear against the said rod or
support, they shall prevent the spring or springs above mentioned or pressure exerted
upon the cutting edges or parts of the dies or cutters and tending to force such dies
or cutters out of position to form screw-threads in articles or objects, from having
any tendency to move the said rod or support in relation to such dies or cutters.
The inclined faces or other suitably shaped parts or other means by which the said
rod or support acts upon the dies or cutters above mentioned in moving them into
position to form screw-threads in the articles or objects to be operated upon, are so
formed that they serve also as means by which the springs aforesaid, in moving the
said dies or cutters out of the position which they occupy when in use in forming
screw-threads may move the said rod or support, if the saiddies or cutters be moved,
so that the parts of such dies or cutters and rod or support which are in contact when
such dies or cutters are in position to form screw-threads in articles or objects to be
operated upon, are no longer in contact. A collar, capable of being slidden or turned
upon the socket above mentioned and connected or caused to act in any suitable
inanner to or upon the rod or support above mentioned or any other suitable means,
may be provided to enable such rod or support to be moved in order that the dies or
cutters may be brought into and held in position to form a screw-thread in an article
or object to be operated upon.

page_text: When a tap constructed according to my invention is screwed into a hole in an
article or object to be operated upon so as to form a screw-thread therein, and the
longitudinal movement of such tap in relation to such article or object or the
movement of such article or object in relation to such tap or the relative movement
of both such tap and article or object is arrested by a previously moving part or
previously moving parts arriving against a suitable stop or stops, the dies or cutters
of the tap, continuing to screw themselves into the said article or object, will move
the holder in which they are mounted in relation to the socket aforesaid so as to
move out of contact with the rod or support aforesaid, the parts by which the dies or
cutters, when in position to forin screw-threads in an article or object to be operated
upon, bear against such rod or support, and when the said holder has been so moved
the spring or springs above mentioned moving the said dies or cutters will cause such
dies or cutters to be disengaged from the screw-thread which they have formed in the
said article or object, so that the tap may be withdrawn from or have removed from
it the said article or object without any unscrewing of such tap or article or object
being requisite. In moving the said dies or cutters so as to disengage them from the
screw-thread which they have formed in an article or object operated upon by such
dies or cutters the spring or springs aforesaid will move the above mentioned rod or
support in a direction opposite to that in which it was moved in placing the said
dies or cutters in position to form a screw-thread in such article or object and in
order that the said spring or springs may more easily move the said rod or support in
such direction, I preferably provide a spring or springs to assist such spring or springs
aforesaid in so moving such rod or support. After the tap has been removed from
the article or object in which a screw-thread has been formed thereby, or after the
article or object in which a screw-thread has been formed has been removed from
such tap, the dies or cutters of such tap are replaced in position to form a screw-
thread, by the holder in which they are mounted and the rod or support above
mentioned being moved in directions opposite to those in which they were moved in
order that the dies or cutters might be disengaged from the article or object in which
a screw-thread was formed thereby. The rod or support above mentioned may be
and is preferably so formed that besides embracing or bearing against the dies or
cutters of the tap in holding them in position to form screw-threads in articles
or objects to be operated upon, it shall bear against the holder in which such dies or
cutters are mounted and so support and protect such dies or cutters from injury.
In the accompanying drawings throughout all the figures of which the same
letters of reference are employed to indicate corresponding parts, Fig. is a side
elevation, Fig. 2 is a plan, and Fig. 3 is an end elevation of one form of tap.
constructed according to my invention.
Fig. 4 is a side elevation and Fig. 5 is an end elevation of a ring or collar serving
as part of the means of moving into working position the dies or cutters of the tap
illustrated in Figs. 1, 2 and 3.
Fig. 6 is a side elevation, Fig. 7 is a plan and Figs. 8 and 9 are end elevations of
the socket in or upon which the movable parts of the tap illustrated in Figs. 1, 2
and 3 are mounted.
Fig. 10 is a side elevation, Fig. 11 is a plan and Figs. 12 and 13 are end
elevations of the holder in which the. dies or cutters of the tap illustrated in
Figs. 1, 2 and 3 are mounted.
Fig. 14 is a plan and Fig. 15 an elevation of the dies or cutters employed in the tap
illustrated in Figs. 1, 2 and 3 and indicating by dotted lines the spring placed
between such dies or cutters.
Fig. 16 is an elevation of the face which one of the dies or cutters illustrated in
Figs. 14 and 15 presents to the other of such dies or cutters.
Fig. 17 is an elevation of one face of the other of the said dies or cutters.
Fig. 18 is a side elevation and Fig. 19 is an end elevation of the spring employed
in conjunction with the dies or cutters illustrated in Figs. 14 and 15, Fig. 20 is a
plan, Fig. 21 is a side elevation and Fig. 22 is an end elevation of a rod mounted
within the socket illustrated in Figs. 6, 7, 8 and 9 and the holder illustrated in

page_text: Figs. 11, 12 and 13 and serving as part of the means by which the dies or cutters
illustrated in Figs. 14 and 15 are moved back into and held in working position
after being disengaged from screw-threads which they have formed.
Fig. 23 is a side elevation and Fig. 24 is an end elevation of a spring employed to
assist in moving in one direction the rod illustrated in Figs. 20, 21 and 22.
Fig. 21 is a side elevation and Fig. 21 is an end view of a pin or key employed
with the collar or ring illustrated in Figs. 4 and 5.
Fig. 7 is a side elevation and Fig. 7 is an end view of a stud inserted in the
socket illustrated in Figs. 6, 7, 8, and 9.
In the tap illustrated in Figs. 1, 2 and 3 (a) (a) are two dies or cutters, (b)
is a holder in which the dies or cutters (a) are capable of being slidden to and
fro, and (c) is a socket in which the holder (b) is mounted so as to be capable
of being slidden lengthwise. Each of the dies or cutters (a) is formed at its.
end (a) with cutting parts or teeth adapted to form screw-threads of the character
required to be formed in the articles or objects operated upon thereby and is arranged
so as to fit into and be capable of being slidden lengthwise in slots formed at
opposite sides of the holder (b), and is formed with a cavity (a2) against one end of
which bears a spring (d) which being placed between the two dies or cutters (a)
so as to be half in the cavity (a2) of each die or cutter (a) tends to move
each of the said dies or cutters (a) so as to bring the ends (a¹) on which
the cutting parts or teeth are formed towards each other and serves when the
tap is in use to withdraw the dies or cutters (a) from the screw-threads
which they have formed in the articles or objects operated upon. The holder (b)
is mounted in the socket (c) so as to be capable of being slidden lengthwise
therein for a distance limited by means of a stud (cs) screwed into the socket (c) and
projecting into a groove (60) formed in the holder (6) and the holder (b) is provided
with a key (61) which, projecting into a groove (cl) formed in the socket (c) prevents
the holder (b) from being turned in the socket (c). In the socket (c) is mounted a
rod or support (e) which projects along the interior of the holder (b) and is capable of
being slidden lengthwise in the socket (c) and holder (b). A spring (k) placed in the
interior of the socket (c) and surrounding the rod or support (e) and bearing at one
end against a collar (e) formed upon the rod or support (e) and at the other end
against a collar (c) formed in the interior of the socket (c) tends to assist in moving
the rod or support (e) in the direction indicated by the arrow A. A screw (e) which
is passed through a ring or collar (f) capable of being slidden lengthwise of the
socket (c) and is made to pass through a slot (c) in the socket (c) and through a
slot (68) formed in the holder (b) and is screwed into the rod or support (e) serves to
prevent such rod or support (e) from being turned in the socket (c) and holder (b) and
also serves to connect the said ring or collar (f) to the rod or support (e) so that the
ring or collar (f) may be used as a means of moving the rod or support (e) lengthwise
in the socket (c) and holder (b). The length of the slot (c) in the socket (c) through
which the screw (e³) passes, serves to limit the extent to which the rod.or support (e)
may be moved lengthwise. The rod or support (e) is formed at one end with
projecting parts (es) between which is a notch capable of receiving the dies or
cutters (a). The dies or cutters (a) are provided with dovetailed ribs (a) engaging
with corresponding grooves in the holder (b). In order that the dies or cutters (a)
'may be inserted in the notch between the projecting parts (es) upon the end of
the rod or support (e) one of such dies or cutters (a) is provided with a
dovetailed rib (a) at one end only so that it may be inserted in the said
notch after the other die or cutter (a) has been placed in position. therein. The
dovetailed rib (6) of the die or cutter (a) which has only one dovetailed
rib, and one of the dovetailed ribs (a) of the die or cutter (a) which bas
two dovetailed ribs serve as projections to act in conjunction with the projecting
parts (e) of the rod or support (e). Each of the projecting parts (es) is provided with
a face (e) which is parallel to the length of the rod or support (e) and with a face (e)
which is inclined to the length of such rod or support (e). The faces (e¹) which aie
parallel to the length of the rod or support (e) serve to hold the dies or cutters (a) in

page_text: position to form screw-threads in articles or objects when the holder (b) in which
the dies or cutters (a) are mounted is pushed into the socket (c) in the direction
indicated by the arrow A and the rod or support (e) is moved in the socket (c) in the
direction opposite to that indicated by the arrow A. The inclined faces (e) serve at
times to enable the spring (d) acting upon the dies or cutters (a) to move the
rod or support (e) in the direction indicated by the arrow A and so when the rod or
support (e) is moved in the direction opposite to that indicated by the arrow A the
inclined faces (e) serve as means by which the dies or cutters (a) may be replaced in
position to form screw-threads in the articles or objects operated upon.
When the tap illustrated in Figs. 1, 2 and 3 is in use and the dies or cutters screw
themselves into an article or object operated upon and the movement of the tap in
relation to such article or object or the movement of such article or object in relation
to the tap or the movements of the tap and article or object in relation to each other
is or are made to cease by means of an adjustable stop or adjustable stops pro-
vided in any suitable place or places in the machine in which the tap is employed,
the dies or cutters (a) continue to screw themselves into the said article or object
for a little time and by so doing cause themselves and the holder (b) to be moved in
relation to the socket (c) and rod or support (e) so that such dies or cutters (a) are
moved out of contact with the faces (e¹) of the projecting parts (e") of the rod (e)
and into contact with the inclined faces (e) thereof and then the spring (d) moving
the dies or cutters (a) to disengage them from the screw-threads which they have
formed causes them to act upon the inclined faces (e) and move the rod or support (e)
in the direction indicated by the arrow A so that such spring (d) may move the
said dies or cutters (a) clear of the screw-threads which they have formed and
enable the separation of the tap from the article or object operated upon to be
effected without any unscrewing. When the tap is to form another screw-thread the
attendant in charge of the machine in which the tap is employed moves the rod or
support (e) in the direction opposite to that indicated by the arrow A and moves the
holder () in the direction indicated by the arrow A and so causing the inclined
faces (e) upon the projecting parts (e") to act upon the dies or cutters (a) moves such
dies or cutters (a) back into position to form screw-threads in articles or objects and
brings the faces (e¹) into position to hold the said dies or cutters (a) in such position.
When the faces (el) hold the dies or cutters (a) in position to form screw-threads in
articles or objects the dies or cutters (a) are unable to transmit to the faces (e¹) any
force tending to move the rod or support (e) lengthwise and the spring (d) causing
the dies or cutters (a) to bear upon the faces (e¹) prevents the spring (k) from moving
the rod or support (e) in the direction indicated by the arrow A.
The movement of the holder () in the socket (c) is so limited by means of the
groove (b) and the stud (c) that when the dies or cutters (a) and holder (b) are
moved in the direction opposite to that indicated by the arrow A the dies or
cutters (a) shall only just be taken out of contact with the faces (e¹) of the projecting
parts (e) and into contact with the inclined faces (e) thereof and the movement of
the rod or support (e) in the socket (c) is so limited by means of the slot (c') and
the screw (e) that such rod or support (e) can not be moved so far in the direction
indicated by the arrow A as to pass out of engagement with the dies or cutters (a).
A tap constructed according to my invention and capable of being used to first
partially form a screw-thread in an article or object operated upon thereby and then
to complete the formation of a screw-thread therein is illustrated in Figs. 25, 26, 27,
and 28 of the accompanying drawings.
Fig. 25 is a side elevation, Fig. 26 is a plan, and Fig. 27 is an end elevation of the
said tap, and Fig. 28 is a transverse section through such tap taken upon the plane
indicated by the line (B) (B) of Figs. 25 and 26, but with a pin or key which appears
in it shown in elevation so as to be clearer.
Fig. 29 is a side elevation, and Fig. 30 is an end elevation of a ring or collar which
being turned enables the dies or cutters of the tap to be adjusted in position.
Fig. 31 is a side elevation, and Fig. 32 is an end elevation of one of two adjustable

page_text: rings or collars in engagement with either of which the ring or collar illustrated in
Figs. 29 and 30 may be placed.
Fig. 33 is an end elevation, and Figs. 34 and 35 are side elevations at right
angles to each other of the other of the said two adjustable rings or collars into
engagement with either of which the ring or collar illustrated in Figs. 29 and 30
may be placed, Fig. 34 also showing a set-screw inserted in the ring or collar
shown in such figure.
Fig. 36 is a side elevation, Fig. 37 is a plan and Fig. 38 is an end elevation of the
socket in or upon which the various movable parts of the tap are mounted and
Fig. 36 also shows a key inserted in such socket.
Fig. 39 is a side elevation, Fig. 40 is a plan and Fig. 41 is an end elevation of a
holder which is mounted in the socket illustrated in Figs. 36, 37, and 38, and a key
which is inserted in the said holder.
Figs. 42 and 43 are side elevations at right angles to each other of one of the
dies or cutters which are mounted in the holder illustrated in Figs. 39, 40
and 41.
Fig. 44 is a side elevation and Fig. 45 is an end elevation of a spring employed in
conjunction with the dies or cutters mounted in the holder illustrated in Figs. 39, 40
and 41.
Fig. 46 is a side elevation, Fig. 47 is a plan and Fig. 48 is an end elevation of a
rod provided with holding faces or cams which is mounted in the socket illustrated
in Figs. 36, 37 and 38, and in the holder illustrated in Figs. 39, 40 and 41 and serves
as means by which the dies or cutters in the said holder may be adjusted into and
held in position to form screw-threads in the articles or objects to be operated upon,
and,
Figs. 49 and 50 are side elevations at right angles to each other and Fig. 51 is an
end elevation of a key or pin inserted in the rod illustrated in Figs. 46, 47 and 48
and serving to place it in connection with the ring or collar illustrated in Figs. 29
and 30 and also as means to move the said rod lengthwise.
In the tap illustrated in Figs. 25, 26, 27 and 28 (a) (a) are two dies or cutters,
(b) is a holder in which the dies or cutters (a) are capable of being slidden to and
fro, and (c) is a socket in which the holder (b) is mounted so as to be capable of
being slidden lengthwise. Each of the dies or cutters (a) is formed at its end (a¹)
with cutting parts or teeth adapted to form screw-threads of the character required
to be formed in the articles or objects to be operated upon thereby, and is arranged
so as to fit into and be capable of being slidden lengthwise in slots formed at opposite
sides of the holder (6) and is formed with a cavity (a²) against one end of which
bears a spring (d) which, being placed between the two dies or cutters (a) so as to
be half in the cavity (a²) of each die or cutter (a) tends to move each of the said
dies or cutters (a) so as to bring the ends on which the cutting parts or teeth are
formed towards each other and serves when the tap is in use to withdraw the dies
or cutters (a) from the screw-threads which they have formed in the articles
or objects operated upon. Each die or cutter (a) is provided with a notch (a³)
into which projects the end of a rod (e) which is formed with holding faces or
cams (e¹) which when the rod (e) is turned in the direction indicated by the arrow C
will move such dies or cutters (a) so that the distance between the cutting parts
or toothed ends (a¹) of such dies or cutters shall be increased. The rod (e) is also
formed with a projection (e²) of a radius equal to the distance from the centre line
of such rod (e) to the sinallest part of each of the cam faces (e¹) thereof and
ordinarily serving to prevent the dies or cutters (a) from being so moved by the
spring (d) that their cutting parts or toothed ends (a¹) are brought too close
together and also serving to prevent the dies or cutters (a) from being accidentally
removed from the holder (b). The rod (e) is placed in the socket (c) and the
holder (b) is placed upon the rod (e) and in the socket (c). In the socket (c) is
formed a key-way or slot (c¹) through which a key (1) is inserted into a slot
formed in the holder (b) so as to be fixed in such holder (b). The key (61) pro-
jecting into the key-way or slot (c¹) in the socket (c) and being of the same width
B

page_text: as and somewhat shorter than such key-way (c) prevents the holder (b) from being
turned in the socket (c), but permits it to be moved lengthwise therein for a
distance sufficient to enable the notches (a³) of the dies or cutters (a) to be placed
upon or withdrawn from the holding faces or cams (e¹) of the rod (e), but not
sufficient to allow the projection (e²) to be withdrawn from the notches (a³) of the
dies or cutters (a). In order that the rod (e) may be turned in the socket (c) but
prevented from being moved lengthwise therein during the ordinary use of the tap,
and in order that it may be moved longitudinally therein in order to allow the dies or
cutters (a) to be removed from the tap as will be hereinafter explained, a pin or
key (e) is inserted into such rod and made to project through a slot (c²) formed
partially around the socket (c) and is provided with a head (e) which engages with a
groove (1) formed lengthwise of the interior of a ring or collar (f) which is placed
upon and capable of being turned upon and moved lengthwise of the socket (c). The
turning of the ring or collar (f) upon the socket (c) is limited by means of the pin
or key (es) and slot (c2) and in order to indicate the limits of the movement ordinarily
required to be given to the ring or collar (f) upon the socket (c) and to provide
means to render it easy to turn such ring or collar (f) in order to move the dies or
cutters (a) into particular positions as will be hereinafter explained, rings or
collars (g) (h) are mounted upon the socket (c) and secured in position thereon by
means of set-screws (g¹) (h¹) respectively and respectively provided with
notches (92) (h) and the ring or collar (f) is provided with a projection (f) which
may be placed in engagement with the notch (2) in the ring or collar (g) and with
a projection (3) which may be placed in engagement with the notch (2) in the
ring or collar (), the placing of the projection (f) in the notch (92) or the placing
of the projection (f³) in the notch (2) being accomplished by the ring or collar (f)
being turned into the required position upon the socket (c) and then moved thereon
in the direction indicated by the arrow A or in the opposite direction. The slot (c2)
in the socket (c) is near one end formed with an enlargement (c³) so that when the
pin or key (e³) is turned by means of the ring or collar (f) or otherwise so as to pass
into such enlargement (c³) the rod (e) may be moved in the socket (c) in the direc-
tion indicated by the arrow A so far that the projection (e²) upon such rod (e) shall
be withdrawn from the notches (3) of the dies or cutters (a) which can then be
withdrawn from the holder (b) to be sharpened or recut or replaced by others. The
socket (c), holder (b) and rod (e) are respectively formed with holes (c), (2) and (e)
which, when the pin or key (e) is brought into the enlargement (c³) of the
slot (c2) have their centre lines in one straight line directed towards the key (61)
in the holder (b) so that when the pin or key (e³) is in the said position a drift
or pin may be passed through such holes (c), (62) and (e) and enable the
key (6¹) to be driven out of the holder (b) and socket (c) so as to enable
the holder (b) to be removed from the socket (c) and the rod (e) to be removed
from the socket (c) and the holder (b). The rings or collars (f) (g) (h) are
preferably provided with milled ribs on their circumferences so as to be more
readily turned as may be requisite from time to time and the socket (c) is
provided with a key (5) in order that it may be more readily held in the lathe
or screwing machine or other machine in which the tap is to be employed.
It is obvious that the two holding surfaces or cains (e¹) of the rod (e) must be alike
and have their corresponding parts at equal distances from the centre line of such
rod (e) and that the distances from the parts of the dies or cutters on which
the said holding faces or cams (e¹) bear to the teeth or cutting edges upon the
ends (a) of such dies or cutters must be so arranged that the teeth or cutting parts
of the two dies or cutters (a) shall be equidistant from the axis or centre-line of the
tap in all the various positions into which the rod (e) may be turned.
In preparing or setting the tap illustrated in Figs. 25, 26, 27 and 28, for use, the
rod (e) is turned by means of the ring or collar (f) into such position that the smallest
parts of the holding faces or cams (e¹) thereof are brought into line with the parts (a4)
of the dies or cutters (a) in conjunction with which they are respectively employed
and the holder (b) is moved in the socket (c) in the direction indicated by the arrow A

page_text: o that the said parts (at) of the dies or cutters (a) are brought into engagement
with the holding faces or cans (el) of the rod (e) and then the ring or collar (f) is
urned so as to cause the holding faces or cams (e¹) of the rod (e) to act upon the dies
or cutters (a) and move them so as to separate their parts (a¹) so far as may be
necessary to enable the articles or objects to be operated upon to have screw-threads
of the required diameter forined in them and then the ring or collar (g) or the ring or
collar (h) is turned into and secured in such position upon the socket (c) that the
projection (f) or the projection (f³) as the case may be, of the ring or collar (f) may
be placed in engagement with the notch (92) or the notch (h2) and if it be desired to
form screw-threads in the articles or objects to be operated upon by means of two
successive cuts or operations, the other ring or collar (h) or (g) as the case may be
may be turned and secured upon the socket (c) in such position that when the second
cut is to be performed upon an article or object, the projection (f³) or (2) as the case
may be, may be brought into engagement with the notch (h) or (92) in such ring or
collar (h) or (g) as the case may be, when the rod (e) has been turned so as to place
the dies or cutters (a) in position to perform such second cut.
When the dies or cutters (a) are in engagement with the holding faces or cams (e¹)
of the rod (e) and the rod (e) has been turned into the position requisite to separate
the parts (a) of such dies or cutters (a) to the extent requisite and the tap is
in use in the formation of a screw-thread in a hole in an article or object
the formation of
or object will continue
screw-thread in such article
a
until the relative movement of the tap in relation to such article or object or of the
said article or object in relation to the tap or the movements of the tap and article or
object in relation to each other is or are arrested by a stop of any suitable kind but
preferably readily adjustable in position which is provided in the machine in which
the tap is employed and then the teeth or cutting parts of the dies or cutters (a)
screw themselves into the article or object
continuing for a very little time to
operated upon will be moved and move with them the holder (b) in the direction
opposite to that indicated by the arrow A so that such dies or cutters (a) being
moved out of engagement with the holding faces or cams (e¹) of the rod (e) will
be disengaged from the screw-thread which they have formed so that the tap
may be withdrawn without being unscrewed from the article or object in which a
screw-thread has been formed. Then the ring or collar (f) being turned by the
attendant in charge of the machine so as to again bring the smallest parts of the
holding faces or cams (e¹) of the rod (e) into line with the parts (a) of the dies
or cutters (a) which are kept by the projection (e²) in position to be engaged by
the said holding faces or cams (e) the holder (6) is moved in the socket (c) by
the attendant in the direction indicated by the arrow A so that the dies or
cutters (a) are again brought into engagement with the holding faces or cams (e¹)
of the rod (e) and the ring or collar (f) is turned again in the direction indicated
by the arrow C so as to set the dies or cutters in position to form a screw-thread in
another article or object or to perform a second cut in the article or object in which
a screw-thread has been partially formed by one cut of the dies or cutters (a) as may
be requisite from time to time.
Fig. 52 is a front elevation of a tap constructed according to my invention similar
to that illustrated in Figs. 25, 26, 27 and 28 but with four dies or cutters instead of
two and adapted for forming screw-threads of larger diameter than those for the
formation of which the tap illustrated in Figs. 25, 26, 27 and 28 is intended.
Fig. 53 is a longitudinal section of the said tap illustrated in Fig. 52 but with two
0 of the dies or cutters, central rod, two pins or keys and a set-screw shown in side
elevation so as to be clearer and also with dotted lines indicating a spring situate in
front of the plane on which the section is taken.
The four dies or cutters of the tap illustrated in Figs. 52 and 53 may readily be
formed from steel bars and are mounted in grooves forined in a holder (b) and are
5 each formed at the end (a¹) with teeth or cutting parts to form screw-threads of the
character required in the articles or objects operated upon and at the other end with
faces (a) to bear against the cam-surfaces (e¹) of the rod (e) which are four in

page_text: number and with notches (a) in engagement with each of which is placed a pro-
jection (2) formed upon one of four blocks (i) each of which is capable of being
slidden lengthwise of one of four holes formed in the holder (b) and each in
communication at one side with one of the grooves in which the dies or cutters (a)
are placed. Four springs (d) are provided to move the dies or cutters (a) towards
the axis or centre-line of the tap and each of such springs (d) bears at one end
against the block (i) employed in conjunction with the die or cutter (a) with
which it is used and at the other end against the plug () screwed into the
holder (b) to close the outer end of the hole in which such block (i) and
spring (d) are placed. The holder (5) shown in Figs. 52 and 53 is provided with
a cover-plate (63) secured thereto by means of screws (64) and serving to retain
the dies or cutters (a) in the holder (b) and such cover-plate (63) is also provided
with a central projection (e²) of a radius equal to or very slightly larger than the
distance from the centre-line of the rod (e) to the smallest parts of the holding
faces or cams (e¹) of such rod (e) and serving like the projection (e²) shown in
Figs. 46, 47 and 48 to hold the dies or cutters (a) with which it is used when they
are moved by the springs (d) used therewith towards the centre-line of the tap in. a
position in which they can be re-engaged with the smallest parts of the holding
faces or cams (e¹) of the rod (e). It is obvious that the projection (e2) in the tap
illustrated in Figs.. 52 and 53 may be provided either on the cover-plate (63) as
shown in the drawing or upon the rod (e). Except in so far as I have already
described the tap illustrated in Figs. 52 and 53 and in that the use of the cover-
plate (63) which is obviously removable renders it unnecessary for the rod (e) to be
capable of being moved at any time lengthwise in the socket (c) and in that the
movement of the holder (b) in the socket (c) is limited by means of a pin (65) and
slot (c) provided for the purpose instead of by the key (b¹) and in that it is un-
necessary for the key (6¹) in such tap to be removed from the holder (b) in order to
enable such holder (b) to be removed from the socket (c), the tap illustrated in
Figs. 52 and 53 is in construction, arrangement, and use, similar to that illustrated
in Figs. 25, 26, 27 and 28.
It is obvious that by more than one notch being provided in one or other or each
of the rings or collars (g) (h), the taps illustrated in Figs. 25, 26, 27, and 28, and
Figs. 52 and 53 can be readily arranged to form screw-threads by more than two
successive cuts or operations and that instead of the ring or collar (f) being provided
with projections (f) (f³) and the rings or collars (g) (h) being provided with notches
to receive the projections on the ring or collar (f), the ring or collar (f) might be
provided with notches to be placed in engagement with projections formed in the
rings or collars (g) (h).
The provision of the means hereinbefore described as provided in the taps illus-
trated in Figs. 25, 26, 27, and 28, and Figs. 52 and 53, by which the dies or
cutters () of a tap constructed according to the forms of my invention which are
illustrated by the said figures can be moved so that their cutting parts or teeth may
be moved into and held at different distances from the axis or centre-line of the tap
at different times as may be requisite in the use of such tap enables such tap to be
used in the forination of screw-threads of different diameters at different times and
also enables the dies or cutters to be once or oftener recut when worn, either for use
in the formation of screw-threads of one diameter or once or oftener for use in the
formation of screw-threads of one diameter and then once or oftener for use in the
formation of screw-threads of smaller diameter.
The holders (b) in the taps illustrated in Figs. 25, 26, 27, and 28 and Figs. 52 and
53 and the holder (b) and rod-(e) in the tap illustrated in Figs. 1, 2 and 3 are so
formed that the dies or cutters (a) of such taps are when in operation supported by
bearing either upon the holders (6) in which they are mounted or upon parts which
bear upon such holders (6) and so such dies or cutters are held firmly and supported
against being bent or strained by the strains to which they are subjected in the use of
the taps.
-
A scale or scales may be arranged in conjunction with one or more or all of the

page_text: collars (f) (g) (h) of either of the taps illustrated in Figs. 25, 26, 27 and 28 and
Figs. 52 and 53 to facilitate the movement of the dies or cutters into particular
positions.
It is obvious that in the taps illustrated in Figs. 12 and 3 and Figs. 25, 26, 27
and 28 a separate spring (d) may be provided for each die or cutter, and in such cases
the springs employed may be placed at the sides of the dies or cutters on which they
act or in any other suitable position.
It is also obvious that either of the taps illustrated in Figs. 25, 26, 27 and 28 and
Figs. 52 and 53 may be used to form a screw-thread in a single operation instead of
by two or more operations and that in any case in which either of such taps is
intended to be always used in forming screw-threads in single operations and not by
two or more successive operations one of the collars (f) (9) may be dispensed with,
the one then used serving to enable the dies or cutters to be set with ease and cer-
tainty in position for forming screw-threads of the diameter requisite.
It is also obvious that the arrangements employed according to my invention may
differ considerably in different cases as may be convenient in practice, for instance the
rod (e) may be tubular and the dies or cutters (a) instead of being of the precise
forms hereinbefore described may be combined with any devices which may be con-
venient to provide for, facilitate or increase the possibility of adjustment to allow of
the recutting of the teeth or cutting parts of such dies or for other purposes as may
be desirable.
Taps constructed according to my invention may be made of any desirable size and
besides being made by the action of automatic devices to release themselves from the
screw-threads which they have formed so as to be capable of being withdrawn without
being unscrewed therefrom are simple in construction and cheap to maintain in work-
ing condition and when constructed in some forms are capable of being readily
adjusted to compensate for the wear of the dies or cutting tools or for forming screw-
threads in holes of different diameters and to form screw-threads of any desirable
degree of accuracy in diameter and when it may be requisite to do so to form screw-
threads of different diameters in different parts of the holes in which screw-threads
are to be formed.
Furthermore the changes in the length of the screw-threads formed by means of
taps constructed according to my invention being accomplished by means of stops of
any convenient kind arranged in any convenient parts of the machines in which such
taps may be employed and not by the adjustment of parts of the taps themselves are
capable of being very readily accomplished.
By different dies or cutters being provided for use in a tap constructed according
to any form of my invention such tap may be easily adapted to form a single screw.
thread or two or more screw-threads of any character, diameter or pitch which may
be requisite or desirable from time to time.
Furthermore the dies or cutters of taps constructed according to my invention
being arranged to be slidden transversely of the holders in which they are mounted are
disengaged from the screw-threads which they have formed without being turned
through arcs in relation to and injuring such screw-threads.
Taps made according to my invention may either be held stationary while the
articles or objects operated upon are caused to revolve or be caused to revolve while
in use.
As is clearly indicated by the accompanying drawings taps constructed according
to my invention may be made free from any parts projecting so as to be dangerous
in any way when such taps are caused to revolve.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
--
1. For forming screw-threads in articles or objects being operated upon in a lathe
or screwing machine, a tap constructed substantially as herein before described and
comprising the following nonts nomaly. (1) throad outting dinn

page_text: in a holder and held in working position by a rod or support against the pressure of
a releasing spring or releasing springs, (2) a holder for the said dies or cutters and
the releasing spring or springs used therewith, capable of longitudinal motion in
order that the dies or cutters may be released from the parts of the rod or support
aforesaid which hold them in working position, (3) a rod or support arranged in the
interior of the tap and provided with parts to bear against the said dies or cutters
and hold them in working position and with faces by means of which the dies or
cutters may be restored to working position, and (4) a collar or other means to enable
the said rod or support to be moved to act upon the said dies or cutters and move
them into working position.
2. Fer forming screw-threads in articles or objects being operated upon in a lathe
or screwing machine or other machine, a tap constructed substantially as herein before
described and comprising the following parts, namely:-(1) thread-cutting dies or
cutters mounted in a holder and held in working position by a rod or support against
the pressure of a releasing spring or releasing springs; (2) a holder for the said dies
or cutters and the releasing spring or springs used therewith, capable of longitudinal
motion in order that the dies or cutters may be released from the parts of the rod
or support aforesaid which hold them in working position; (3) a rod or support
arranged in the interior of the tap and capable of being moved lengthwise therein
and provided with parts to bear against the said dies or cutters and hold them in
working position and with faces by means of which the dies or cutters may be
restored to working position; and (4) a collar or other means to enable the said rod
or support to be moved lengthwise to act upon the said dies or cutters and move
them into working position.
3. For forming screw-threads in articles or objects being operated upon in a lathe
or screwing machine or other machine, a tap constructed substantially as hereinbefore
described and comprising the following parts, namely:-(1) thread-cutting dies or
cutters mounted in a holder and held in working position by a rod or support against the
pressure of a releasing spring or releasing springs; (2) a holder for the said dies or
cutters and the releasing spring or springs used therewith capable of longitudinal
motion in order that the dies or cutters may be released from the parts of the rod or
support aforesaid which hold them in working position; (3) a rod or support arranged
so as to be capable of being turned in the interior of the tap and provided with parts
to bear against the said dies or cutters and hold them in working position and with
faces which when the rod or support is turned may act upon the dies or cutters and
move them into working position, and (4) a collar or other means to enable the said
rod or support to be turned to act upon the said dies or cutters and move them into
working position.
4. For forming screw-threads in articles or objects being operated upon in a lathe
or screwing machine or other machine, a tap constructed substantially as herein before
described and comprising the following parts, namely:-(1) thread-cutting dies or cutters
mounted in a holder and held in either of two or more working positions by a rod or support
against the pressure of a releasing spring or releasing springs; (2) a holder for the said dies
or cutters and the releasing spring or springs used therewith, capable of longitudinal
motion in order that the dies or cutters may be released from the parts of the rod or
support aforesaid which hold them in working position; (3) a rod or support arranged
so as to be capable of being turned in the interior of the tap and provided with parts
to bear against the said dies or cutters and hold them in either of two or more working
positions and with faces which when the rod or support is turned may act upon the
dies or cutters and move them into the required working position; (4) a collar or
other means to enable the said rod or support to be turned to act upon the said dies
or cutters and move them into the required working position.
Dated this Second day of April 1808
HOWARD
CHEETHAM,
Manchester, Agent to the Applicant.