Improvements in Chucks for Holding Tools in Boring, Tapping, and like Machines.
Year: 1893

page_text: Date of Application, 23rd May, 1893
Complete Specification Left, 13th Feb., 1894-Accepted, 17th Mar., 1894
Improvements in Chucks for Holding Tools in Boring, Tapping,
and like Machines.
A communication from abroad by ALFRED AMES FISHER, Manufacturer, and
WILLIAM G. NELSON, Mechanic, of 471 and 473, Eighteenth Street,
Brooklyn, in the State of New York, United States of America.
I, JOHN MAGRATH KELLY, of 20 Cheapside, in the City of London, Merchant,
do hereby declare the nature of this invention to be as follows:-
This invention relates to chucks and has especial reference to drill chucks and
others of the class used in machines for boring tapping and similar purposes.
In machines of the character mentioned, the chuck is usually rigidly fitted to the
drive spindle and consequently when employed for tapping, it becomes necessary as
the tap approaches the bottom of the machine to prevent the tap from striking the
bottom and receiving the full power transmitted through the spindle, which would
result in the breaking of the tap, or the derangement of the driving mechanism.
Even the exercise of the greatest care does not avoid these. difficulties and
therefore it has been found expedient to provide a chuck in which the tool holder
is held by friction to the inner end of the spindle and is adapted to yield under a
predetermined force to remove the strain from the chuck and its actuating
mechanism.
Another great drawback to the form of chucks now in use, is the tendency of the
meeting surfaces of the two-part chuck to wear unevenly thereby throwing the
point of the tool out of centre to the great detriment of the work and the liability
of breaking the tool.
The object of my invention is to overcome these difficulties and especially to
provide a two-part chuck whose meeting surfaces form bevelled seats, which
always insures the perfect centering of the tool.
The inner end of the drill spindle is provided with an enlarged head suitably
recessed to receive the inner end of the chuck and provided at the base of the
recess with an inwardly inclined seat..
From the face of the head project suitable pins and said head at points between
these pins is provided with threaded holes for a purpose hereinafter stated.
When
The tool holding part of the chuck consists of a cylindrical or other socket piece
into which the shank of the tool is inserted in the usual manner, and said socket is
preferably made square at its inner end and is provided with a collar. A hard
rubber, paper, or fibrous friction piece is fitted upon the inner squared end of the
socket piece and is securely held by screws passing through it and entering the
collar the said friction piece being of disc form and having its opposite faces flat
and parallel for a portion of its width and its remaining surface tapered on both
sides to impart to the edge of the friction piece a V-shape in cross section.
the two parts of the chuck are in position the flat face of the friction piece will
find a seat against a corresponding surface at the base of the recess in the head and
the bevelled surface will be seated against the bevelled or inclined portion of said
head. The opposite bevelled face of the friction piece will also he engaged by a
similarly formed inwardly tapered seat on the inner face of a clamping disc, the
said disc having also its inner face recessed to receive the collar on the socket
piece and having a flange provided with holes some of which are adapted to receive
the pins before referred to for locking the two parts of the chuck against lateral

page_text: twisting strain while the other holes receive threaded bolts or screws which engage
the holes in the head as shown.
From this description it will be understood that the two main parts of the chuck
are securely clamped together by screwing the disc to the head and the frictional
contact between the spindle and socket piece is such that the two move together as
one piece until the strain or resistance upon the tool overcomes the frictional
contact and allows the spindle to slip upon the friction piece carried by the socket.
As the socket which carries the tool also carries the bevelled friction piece and
this piece works upon the bevelled seats before mentioned, it is manifest that
whatever there may be between this piece and its seats may be compensated for by
adjusting the clamping disc and that owing to the bevelled arrangement of the
friction piece and its seats the tool is also properly centred, a feature that is not
capable in those chucks where the discs are plain flat pieces of uniform thickness
which, after slight wear must be built up by inserting wedges or other pieces to
properly centre the tool.
In a modified form which forms a part of this invention the enlarged head is
provided with an internal screw thread and with guide pins only, such pins
engaging with holes in the clamping disc. This disc is also provided with inner
and outer shoulders respectively and with an outwardly extending sleeve portion,
the sleeve holder being confined between the socket holder and an outer nut.
This nut has a flange portion externally threaded and adapted to engage the
threads on the interior of the head and it has a cylindrical portion or sleeve fitted
over the sleeve of the clamping disc and provided with recesses which may be
engaged by a spanner or other tool for operating it so that this clamping disc is
forced tightly against the friction piece. The socket piece or holder is made of
the usual form and has a head into which the shank of the tool is adapted to be
fitted.
The socket piece is provided with an annular groove and the collar of the socket
piece is provided with a recess in which is seated a pin adapted to engage with said
groove and having a spring bearing upon it.
Dated the 23rd day of May 1893.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Chartered Patent Agent,
For the Applicant.
COMPLETE SPECIFICATION.
Improvements in Chucks for Holding Tools in Boring, Tapping,
and like Machines.
A communication from abroad by ALFRED AMES FISHER, Manufacturer, and
WILLIAM G. NELSON, Mechanic, both of 471 and 473, Eighteenth Street,
Brooklyn, in the State of New York, United States of America.
1, JOHN MAGRATH KELLY of 20 Cheapside, in the City of London, Merchaut,
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 chucks and has especial reference to drill chucks and
others of the class used in machines for boring, tapping and similar purposes.
In the accompanying drawings
Fig. 1 is a longitudinal sectional view of a chuck embodying the invention, said
chuck holding a tapping tool.
Fig. 2 is a longitudinal section of the body or driving spindle part of the chuck.
Fig. 3 is a perspective view of the tool holding part of the chuck.
Fig. 4 is a longitudinal section of a modified form of chuck, said chuck having

page_text: a tool holder which is shown in elevation, and Fig. 5 is an end view of same with
the tool holder removed.
In machines of the character mentioned the chuck is usually rigidly fitted to the
drive spindle and consequently when employed for tapping it becomes necessary as
the tap approaches the bottom of the machine to prevent the tap from striking the
bottom and receiving the full power transmitted through the spindle, which
would result in the breaking of the tap, or the derangement of the driving
mechanism. Even the exercise of the greatest care does not avoid these difficulties
and therefore it has been found expedient to provide a chuck in which the tool
holder is held by friction to the inner end of the spindle and is adapted to yield
under a predetermined force to remove the strain from the chuck and its actuating
mechanism.
Another great drawback to the form of chucks now in use is the tendency of the
meeting surfaces of the two-part chuck to wear unevenly thereby throwing the
point of the tool out of centre to the great detriment of the work and the liability
of breaking the tool. The object of this invention is to overcome these difficulties
and especially to provide a two-part chuck whose meeting surfaces form bevelled
seats, which always ensures the perfect centering of the tool.
i
Referring to Figs. 1, 2 and 3, A represents a drill spindle or driver to which the.
chuck is to be attached. The inner end of this spindle is provided with an enlarged
head a suitably recessed at Fig. 2, to receive the inner end of the chuck and
provided at the base of the recess with an inwardly inclined seat as shown
particularly in Fig. 2. From the face of the head a project suitable pins ², and
said head at points between these pins is provided with threaded holes 63 for a
purpose hereinafter stated.
The tool holding part of the chuck consists of a cylindrical or other socket B
into which the shank of the tool is inserted in the usual manner, and said socket is
preferably made square at its inner end and is provided with a collar B'. A hard
rubber, paper, or fibrous friction piece C is fitted upon the inner squared end of
the socket, and is securely held by screws passing through it and entering the
collar B1, the said friction piece being of disc form and having its opposite faces 2
and 3 flat and parallel for a portion of its width and its remaining surface tapered
on both sides at 5 and 6 to impart to the edge of the friction piece a V shape in
cross section. When the two parts of the chuck are in position the flat face 2 of
the friction piece C will find a seat against a corresponding surface at the base of
the recess in the head a and the bevelled surface will be seated against the
bevelled or inclined portion & of said head. The opposite bevelled face 6 of the
friction piece C will also be engaged by a similarly formed inwardly tapered seat c
on the inner face of the clamping disc D, the said disc having also its inner face
recessed at d to receive the collar B' on the socket piece B, and having a flange e
provided with holes g and h, the former being adapted to receive the pins 62 for
locking the two parts of the chuck against lateral twisting strain while the holes h
receive threaded bolts or screws which engage the holes in the head a as
shown.
From this description it will be understood that the two main parts of the chuck
are securely clamped together by screwing the disc D to the head and the frictional
contact between the spindle A. and socket is such that the two move together as
one piece until the strain or resistance upon the tool overcomes the frictional
contact and allows the spindle to slip upon the friction piece carried by the socket.
As the socket which carries the tool also carries the beveled friction piece C and
this piece C works upon the beveled seats before mentioned, it is manifest that
whatever there may be between this piece and its seats may be compensated for by
adjusting the clamping disc and that owing to the beveled arrangement of the
friction piece and its seats the tool is also properly centred, a feature that is not
capable in those chucks where the discs are plain flat pieces of uniform thickness
which, after slight wear must be built up by inserting wedges or other pieces to
properly centre the tool.

page_text: 1,2
In the modified form illustrated in Figs. 4 and the enlarged head a is provided
with an internal screw thread a¹ and with pins only suen pins projecting from a
shoulder of same and engaging with holes in a flange of the clamping disc D. This
disc is also provided with inner and outer shoulders m m respectively and with
an outwardly extending sleeve portion n, the sleeve holder being confined between
the socket B and a nit R.
The nut R has a flange portion r externally threaded and adapted to engage the
threads on the interior of the heal a and it has a cylindrical portion or sleeve S
fitted over the sleeve of the clamping disc and provided with recesses t which may
be engaged by a spanner or other tool for operating it so that the clamping disc is
forced tightly against the friction piece C. The socket piece or tool holder T is
made of the usual form and has a bead T'as shown into which the shank of the
tool is adapted to be fitted. The socket piece is provided with an annular groove v
and the annular collar B' of the socket piece B is provided with a recess in which
is seated a pin wadapted to engage with said groove and having a spring w
bearing upon it as shown.
Having particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, as communicated to me from
abroad by my foreign correspondent, I declare that what I claim is :-
1st. In a chuck, the driver having a recessed head provided with an inclined or
tapered seat, a tool holder having a friction piece adapted to enter said head and
provided with tapered edge fitting said seat, a clamping piece having a tapered or
beveled seat adapted to receive a corresponding beveled or tapered portion on the
opposing face of the friction piece, and means for uniting the clamping piece to
the driver, substantially as herein described.
2nd. In a chuck, the combination of the body piece for attachment to the driver,
having a recessed head with beveled seat, said head having the projecting pins,
holes, a socket carrying the tool and provided with a collar, a friction piece
secured to said collar and having its faces oppositely beveled, a clamping piece
having a recess for said collar and a beveled seat, said clamping piece having also
holes to receive the pins on the body piece, and screws or bolts for securing the
body piece and clamping piece together, substantially as herein described.
3rd. A two-part chuck having a friction piece with beveled edges between its
adjoining faces the driving portion having a recessed heal a clamping disc located
within the head having an inner face beveled to fit the corresponding face of the
friction piece, and a nut slidable upon the clamping disc and adapted to enter
the recessed head and bear upon the clamping disc with equal pressure on all
sides.
4th. In a chuck the driver with its recessed head having a shoulder and
internally threaded entrance, a socket for the tool-holder having a friction piece
by which motion is transmitted from the driver to the driven portion, a clamping
disc adapted to enter the head of the driver and bear against the friction piece,
and a nut engaging the threaded entrance of the recessed head of the driver and
adjusting the clamping disc whereby the latter bears with equal force on all sides
of the friction piece substantially as herein described.
5th. In a chuck, the driver with its recessed head having internal shoulder
and internally threaded entrance, a socket for the tool-holder having a collar B
and friction piece by which the motion of the driver is communicated to the
socket, a clamping disc adapted to enter the recessed head an bear against the
friction piere, having a flange, shoulders m m and sleeve a slidably mounted upon
the socket, and a nut mounted upon the clamping disc to bear against one of its
shoulders and provided with an externally threaded flange adapted to engage the
internally threaded entrance to the recessed head of the driver, whereby when the
nut is turned the clamping disc is adjusted with equal force against all sides of
the friction piece, substantially as herein described.
6th. In a chuck, a driver having a recessed head, a driven portion having a

page_text: socket provided with a friction piece and annular collar having a recess, a spring
actuated pin in said recess a clamping disc inclosing said collar, and a nut threaded
in the recessed head of the driver and bearing against the clamping disc.
Dated this 12th day of February 1894.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Chartered Patent Agent,
For the Applicant.