Improvements in Drill-chucks.
Year: 1896

page_text: Date of Application, 14th Apr., 1896-Accepted, 16th May, 1896
Improvements in Drill-chucks.
I, DAVID WEIR, of 80 Pearl Street, Hartford County of Hartford, and State
of Connecticut, United States of America, Tool Maker, do hereby declare the
ature 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:-
The object of my invention is to provide a drill-chuck which is adapted to
ecurely hold a twist-drill or a like tool with either a cylindrical straight shank or
tapered shank, the chuck-jaws automatically adapting themselves to the form of
he drill.
To this end my invention consists in the details of the several parts making up
the chuck-jaws and their operating mechanism, and the combination of such parts
as more particularly hereinafter described and pointed out in the claims.
Referring to the accompanying drawing:
Figure 1 is a detail side view of the chuck with parts broken away to show
construction.
Figure 2 is a detail view in central lengthwise section of the chuck.
Figure 3 is a detail view in cross section of the chuck taken on the plane denoted
by line x-x of Fig. 1.
Figure 4 is a detail view of the chuck-jaw, shoe and the link forming part of the
drill-clamping mechanism.
In the accompanying drawing the letter a denotes the chuck-body as a whole,
terminating at one end in a cone b and having a stem c of smaller diameter than the
cone, said stem being threaded to receive a cap d. This stem may be provided
with an axial socket e into which the tapered end of a drill-spindle may be inserted
for the purpose of holding the chuck, or the stem may be elongated and tapered to
fit a socket in a drill-spindle, it being merely essential that the chuck-body shall be
provided with some means for attachment to a spindle.
In the form of the device as shown, three radial jaw sockets f are formed in
the substance of the chuck-body, these sockets opening through the periphery of
the cone and being regularly disposed at even intervals about the axis of the
chuck-body.
In the space between the back of the cone b and the face of the cap d on the
stem of the chuck-body, a sliding ring g is fitted, the periphery of the ring having
a screw-thread which meshes with the screw-thread on the inner surface of the
sleeve, this sleeve being held between a shoulder on the cap d and another
shoulder on the conical shell i. The sleeve is held against lengthwise movement
on the chuck-body but is free to rotate, the outer surface being knurled or
roughened to afford a proper grasp for the hand.
In each of the jaw-sockets there is located a jaw k having a holding face k¹ and
fitted closely but sliding freely in the jaw-socket. The back of the jaw for a
considerable part of its length from the nose back is tapered to conform to the
slope of the surface of the cone, and on this part of the jaw there is mounted a
bearing piece or shoe l, a rounded bearing about midway of the shoe resting in a
properly shaped socket k³ to enable the jaw to tilt on the shoe, the outer surface of
which is in sliding contact with the inner surface of the shell i. By this construction
of the parts, the jaw is enabled to rock on the bearing piece or shoe and locate the
grasping face k' either parallel to or at an angle with the axis of the chuck-body,

page_text: the position of the jaw being determined by the shape of the drill-shank introduced
between the jaws when the latter are opened.
Each jaw is connected to the ring g by means which permit the free rocking
movement of the jaw but cause it to be moved lengthwise along the chuck-body in
conformity with the sliding movement of the ring, which sliding movement is
imparted by a rotary movement of the sleeve as described. The specific
connecting means in the present instance consist of a link m united to the ring g by
means of a pivot n and having a flat rounded head m¹ which fits within a rounded
socket in the chuck-jaw.
Each jaw-socket in the cone 6 is preferably broadened near the surface of the
cone, and shoulders are formed for the support of the shoe, which is broader than
the chuck-jaw.
The shoe l, being connected to the jaw k, by the rounded bearing engaging the
socket 3 in the back of the jaw, in which it loosely fits, operates to hold the jaw
from dropping radially inward into the drill-socket in the chuck-body. This
function of the broadened shoe resting as it does on the shoulder is clearly
illustrated in Fig. 3 of the drawings, and this feature of my improvement is of
value in increasing the facility with which the tool can be used.
The shell is preferably provided with a left hand screw and is screwed upon the
front end of the cone, to which it is fastened by interengaging threads, although
other means of fastening may be provided. The cap d is also provided with a
thread, preferably left handed, and engaging a thread on the stem.
The operation of the device is as follows:-
The chuck having been secured to a drill-spindle the ring.g is run back by a
rotary movement of the sleeve and the jaws k are drawn inward until the distance
between their holding faces is sufficient to enable the shank of a drill to be
inserted; a reverse rotary movement of the sleeve h then feeds the ring g along
the stem of the chuck-body and thrusts the chuck-jaws outward until the faces k¹ of
the chuck-jaws encounter the surface of the drill-shank aud' bind thereon, the loose
mounting of each jaw on the shoe on which it can rock lengthwise and the pivotal
connection of the jaw with the ring which permits the rocking movement, aiding to
cause the jaw to automatically adjust itself in proper position to bind firmly upon
the shank of the drill whether the latter is cylindrical or tapered.
The pivotal connection of the ring and jaw by means of the liuk, and the angular
position of the latter with reference to the centre line of the jaw, gives a leverage
by means of which an extremely firm grasping action of the jaw is obtained by the
combination of the parts as described.
It is obvious that the particular means by which each jaw and bearing piece or
shoe is united so as to permit a rocking action between the parts, may be varied,
and also that the special construction of the link and its means of connection to the
jaw and the sleeve may be varied without departing from the main feature of the
invention, which is not limited to the specific and particular construction of
the parts as described; other means within the skill of the artisan being obviously
applicable in the embodiment of the main feature of the invention which resides in
the tilting jaw with the bearing piece and the pivotal connection between the jaw
and the jaw-feeding mechanism substantially as herein before described.
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. In a drill-chuck, in combination, a chuck body having jaw-sockets, a bearing
piece having a tapered bearing surface and fastened to the chuck-body on which it
is firmly held against rotation, lengthwise sliding jaws located in the sockets, a
rocking shoe interposed between the back of the jaw and the bearing piece fast to
the chuck-body, jaw-feeding mechanism and pivotal connecting means uniting each
jaw, and the jaw-feeding devices, all substantially as described.
2. In combination, in a drill-chuck, a chuck-body having radial jaw-sockets,

page_text: reciprocating jaws mounted in said jaw-sockets, a rocking shoe interposed between
the back of each jaw and the inner face of a non-rotary conical shell fast to the
chuck-body, a sliding ring having a peripheral thread, a rotary sleeve mounted on
the chuck-body and with an interior thread engaging the thread on the sliding
ring, and a link pivotally connecting the ring and each chuck-jaw, all substantially
as described.
3. In a drill-chuck, in combination, a chuck-body having radial jaw-sockets,
reciprocating jaws mounted in said jaw-sockets, a rocking shoe interposed between
the back of each jaw and the inner face of a conical shell fast to the chuck-body,
the said shoe having a socket in the chuck-body broader than the socket for the
chuck-jaw, means for loosely connecting the bearing piece and the chuck-jaw and
holding the latter against any radial movement independent of the shoe, a sliding
ring mounted on the chuck-body and having a peripheral thread, a rotary sleeve
mounted on the chuck-body and held between fixed shoulders thereon with an
interior thread engaging the thread on the sliding ring, and a link pivotally
connecting each chuck-jaw and said sliding ring, all substantially as described.
4. In combination, in a drill-chuck, a chuck-body terminating at one end in a
coue, said cone having radial jaw-sockets extending through its periphery,
shoulders in each of said jaw-sockets as a bearing for a shoe, a conical shell fitting
and secured to the conical end of the chuck-body, a cap secured to the other end of
the chuck-body and having an inward facing shoulder, a rotary sleeve held
between said shoulder. on the cap and the end of the shell, a plural number of
chuck-jaws each located in its respective socket and having a holding face and a
rounded socket in the tapered back of the jaw, a shoe having a rounded projection
fitting said socket in the jaw with a space between the shoe and the back of the
jaw whereby a rocking action of the parts upon each other is permitted, a rounded
socket in one end of each jaw near its inner end, a link pivoted to a sliding ring at
one end and having on the other end a rounded head fitting the said socket in the
end of the chuck-jaw, and the sliding ring having a peripheral thread fitting the
thread on the inner surface of the rotary sleeve, all substantially as described.
Dated the 16th day of January 1896.
DAVID WEIR.
D. Young & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicant.
DAVID WEIR.
D. Young & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicant.