Year: 1888

page_text: I, ROBERT JAMES PRATT, of Greenbush Heights, in the County of Rensselaer and
State of New York, United States of America, Civil Engineer, 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 :-
My invention relates to certain new and useful improvements in or relating to
Chucks, and presents a construction of simple and durable character, economical in
point of manufacture, readily manipulated and of especial efficiency in operation.
In the accompanying drawings, I have illustrated two modifications, each embodying
the main features of the invention.
Figure 1 represents, in side elevation, one of these modifications.
Fig. 2 represents a like view with the jaw-adjusting sleeve removed.
Fig. 3 represents a longitudinal section of the chuck, some of the interior parts
being shown in elevation.
Fig. 4 represents a front end elevation of the parts shown in Fig. 2.
Fig. 5 represents a like view with the chuck jaws removed.
Fig. 6 represents in end elevation and section the chuck jaws and spring.
Fig. 7 represents in perspective one of the chuck jaws.
Fig. 8 represents in end elevation the eccentric which operates the jaws.
Fig. 9 represents in perspective the follower which transmits power from the eccentric
to the jaws.
Fig. 9ª represents in side elevation a modified arrangement of chuck jaws spring and
follower.
Fig. 10 represents in side elevation another form or modification of my invention.
Fig. 11 represents a longitudinal section of the same, some of the parts being shown
In elevation.
Fig. 12 represents a front end elevation.
Fig. 13 represents a cross section through the eccentric.
Fig. 14 represents in perspective the clamping jaws and
Fig. 15 represents a wrench or key for operating either form of the chuck.
Similar figures of reference indicate similar parts throughout the several views.
The main body or stock 1 of the chuck consists desirably of a malleable iron
casting, preferably of cylindrical form and suitable finish, and is cored or reamed out
so as to form a longitudinal passage 16. The body 1 is also drilled transversely, as
shown, for the reception of an eccentric pin, turned from a single piece of metal, the
ends 18, 20 of said pin constituting gudgeons having bearings in the walls of the main
body 1, so as to be revoluble therein. These gudgeons are substantially flush with the

page_text: exterior surface of the main body of the chuck, thereby obviating any liability of
accidentally turning the pin and loosening the eccentric grip after the said grip has
been set, as hereinafter described. The cam surface or eccentric portion proper 19,
of the pin is located entirely within the passage 16, and designed to impart a small
longitudinal movement to a jaw-actuating follower, having a stem 17, fitting closely
within the passage 16.
The main body of the chuck is somewhat reduced in diameter at its forward end 6,
for a portion of its length, and said reduced portion 6, is provided with equidistant
slots, and is also provided with an external screw-thread adapted to engage with an
internal screw-thread upon an adjustable sleeve 2, said sleeve having a milled
periphery 3. Within the slots or recesses of the reduced portion 6 of the chuck
extend the wings 11, 14, 15 of the follower, and upon these wings rest respectively
the jaws 7, 8, 9. Said jaws are preferably of the particular construction illustrated
in the drawing, having V-shaped edges parallel with each other and adapted to grasp
and securely hold between them with a uniform and even bearing a drill or other
article. The jaws are provided with bevelled recesses, having overlapping projection 21
said recesses being designed to receive and retain a band spring 10, whose function is
to release the jaws from contact with the tool or other article and hold them in a
distended position, as indicated in Figs. 2, 4, and 6, when the chuck setting mechanism
is released. One of the jaws as 8, is provided with a pin projection 22, within its
recess, and against said pin abut the ends of the spring 10, thereby locking the spring
in place with respect to the jaws, and preventing its ends from slipping out from the
recess, which would interfere with the proper action of the jaws. At their forward
ends the jaws are provided with a bevelled or inclined outer surface 24, and the sleeve 2
is narrowed or bevelled at its forward end to correspond therewith, whereby a move-
'ment of the sleeve toward the main body 1 of the chuck will cause the jaws to approach
each other.
The end or gudgeon 20, of the eccentric pin is drilled at 4, and a transverse
opening 5 sawed in said end thereby forming a cavity for the reception of the shank
and wings 27, of the wrench or key which sets and releases said eccentric. The main
body of the wrench may be cheaply and expeditiously produced from a corresponding
length of rod metal, which is drilled at its upper portion for the reception of the
crossbar 26, and is turned so as to taper in the direction of its length, as indicated at
25, the wings being formed by suitable cutting tool.
The parts of my invention being constructed and arranged as described, the operation
thereof is as follows:-
The sleeve 2 is revolved by hand so as to travel towards the left with respect to
Fig. 1, thereby permitting the jaws (7, 8, 9) to separate under the influence of the
spring 10, until said jaws assume the position indicated more clearly in Fig. 6. The
drill or other article is then inserted in the opening made by the jaws, and the sleeve 2
thereupon revolved so as to travel toward the right, the effect of this movement being
to cause the jaws to approach each other and adjust the position of the article to be
held. If the article to be held by the chuck be comparatively small that is having a
diameter or distance across its axis of say less than three sixteenths of an inch, sufficient
pressure may be obtained by thus turning the sleeve 2 by hand to securely grip it in
the chuck, but if the article be of a diameter or distance across its axis say exceeding
three sixteenths of an inch then I apply that which is hereinafter referred to as the
'secondary grip' or 'lock.' For this purpose I insert the wings 27 of the wrench
within the opening 5 of the eccentric pin and revolve said wrench and pin, the eccentric
portion 19 forcing the stem 17 of the follower outward. This movement is imparted
through the medium of the wings 11, 14 15, of the follower to the jaws 7, 8, 9, forcing
the inclined surfaces 24 against the incline 23 of the sleeve 2, and thereby causing the
jaws to grip the drill or other article with greatly increased power and at the same
time by correspondingly increasing the pressure against the inner inclined surfaces of
the sleeve 2, to securely 'lock' the said sleeve 2, in the position into which it was
moved for imparting that which. under such circumstances constitutes the 'primary
grin.'

page_text: After the chuck is thus set the wrench is removed and there are no projecting parts
from the eccentric whereby said eccentric can be instantly or accidentally operated so
as to release the tool.
In removing from the chuck a drill or other article the eccentric is first released by
means of the wrench, whereupon the sleeve may be operated to permit a separation of
the jaws.
Referring to the drawings illustrating the second form of construction of my
invention, it will be seen that the main body or stock is provided with a longitudinal
tapering passage 29, whereby it may be secured upon the operating shaft or spindle,
an internal rectangular passage or chamber 31 within which is located the actuating
cam, and a passage within which is adapted to fit closely the jaw actuating
follower 33.
The stock is also provided with a transverse passage for the reception of an eccentric
pin, the ends 34 and 35 of said pin constituting gudgeons, having bearing surfaces in
the walls of the stock, so as to be revoluble therein. 36 represents a cam button
mounted eccentrically upon the pin, and designed to impart a small longitudinal
movement to the said jaw actuating follower 33.
*The main body of the chuck is somewhat reduced in diameter at its forward end for
a portion of its length and said reduced portion is provided with diametrically opposite
slots or recesses 37 and 38 and is also provided with an external screw-thread adapted
to engage with an internal screw thread upon an adjustable sleeve 30 the said sleeve
having a milled periphery 31.
Upon the follower 33, rest the interlocking jaws 39 and 40 of the peculiar
construction shown. The interior surfaces of these jaws are provided with a series of
teeth 41, having inwardly inclined V-shaped edges alternating with recesses conforming
to the contour of the corresponding teeth on the other jaw, the relative positions of teeth
and recesses on the jaws being such that a tooth of one jaw registers with a recess of
the other jaw. It will be noticed that the apex of the angle formed by the sides of the
teeth, and the apex of the angle formed by the sides of the recesses, are in the same
line. Consequently when a tool is clamped between the jaws a solid backing or
clamping surface is presented by each jaw, thereby preventing the interlocking jaws
from cutting into or mutilating the drill or other tool.
The jaws are provided with perforations 43 adapted to receive and retain a spring 44,
whose function is to release the jaws from contact with the tool and hold them in a
distended position, when the chuck, setting mechanism is released. At their forward
ends the jaws are provided with a beveled or inclined outer surface and the sleeve 30
is narrowed or beveled at its forward end to correspond therewith, as in the preceding
form of the invention, whereby a movement of the sleeve towards the main body of the
chuck will cause the jaws to approach each other and interlock, clamping the drill or
other tool between them.
The eccentric is operated as before by the wrench or key shown in Figure 15.
In the arrangement of chuck jaws, spring and follower which is shown at figure 9*
and which is equally applicable to the two forms of chuck shown, the springs 10° take
the place of the spring 10 as herein before described. These springs 10ª are secured
by entering slits formed respectively in the jaws and wings of the followers as
shown.
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. A chuck consisting of a main body portion having a hollow interior and screw-
threaded at its forward end, said forward end being provided with slots or recesses,
clamping jaws located within said recesses and inclined or beveled at their forward
ends, a follower for operating said jaw, an eccentric or cam for actuating said follower
and an internally screw-threaded sleeve having a tapering aperture and engaging with
the external screw-thread of the main body, substantially as described and illustrated
in the accompanying drawing.

page_text: 2. A chuck, consisting of a main body portion, having a hollow interior and screw-
threaded at its forward end said forward end being provided with slots or recesses,
clamping jaws located within said recesses and inclined or beveled at their forward
ends, a follower consisting of a stem fitting said hollow interior and side wings which
operate the clamping jaws, an eccentric or cam for actuating said follower and an
internally screw-threaded sleeve having a tapering aperture and engaging with the
external screw-thread of the main body, substantially as described and illustrated in
the accompanying drawing.
3. A chuck, consisting of a main body portion, having a hollow interior and screw-
threaded at its forward end, said forward end being provided with slots or recesses,
spring-distended clamping jaws located within said recesses and inclined or beveled at
their forward ends a follower for operating said jaws, an eccentric or cam for actuating
said follower and an internally screw-threaded sleeve having a tapering aperture and
engaging with the external screw-thread of the main body, substantially as described
and illustrated in the accompanying drawing.
4. A chuck consisting of a main body portion having a hollow interior and screw
threaded at its forward end said forward end being provided with slots or recesses
clamping jaws located within said recesses and inclined or beveled at their forward
ends, a spring or springs for distending said jaws, a follower consisting of a stem
fitting said hollow interior and side wings for operating the clamping jaws, an eccentric
or can actuating said follower and an internally screw-threaded sleeve having a
tapering aperture and engaging with the external screw-thread of the main body
substantially as described and illustrated in the accompanying drawing.
5. In a chuck the combination with the clamping jaws of a spring for distending
them, said jaws being provided with recesses having overlapping flanges for the
reception and retention of the spring and one of the jaws having a projection against
which the ends of the spring abut substantially as described and illustrated in the
accompanying drawing and particularly at figure 6 thereof.
6. In a chuck, the combination with the main body portion, sleeve, clamping jaws,
and follower, of an eccentric or cam having its shaft journaled in the walls of the
main body of said chuck and substantially flush therewith, said eccentric shaft having
at one end an aperture for the reception of an adjusting key or wrench, substantially
as described and illustrated in the accompanying drawing.
7. In a chuck, the combination with the main body portion, sleeve, clamping jaws,
and follower, of the eccentric or cam described consisting of a single piece of metal,
having at its central portion a cam projection, and at its opposite ends bearings or
gudgeons adapted to turn within the walls of the main body of the chuck one of said
gudgeons being slotted transversely for the reception of an operating key or wrench,
substantially as described and illustrated in the annexed drawing.
8. In a chuck, the spring-distended clamping jaws each of said jaws being provided
with a series of teeth having inwardly inclined V-shaped edges alternating with a
series of recesses, conforming to the contour of the corresponding teeth on the other
jaw, and the apex of the angle formed by the sides of the teeth and the apex of the
angle formed by the sides of the recesses being in the same plane, substantially as
described.
JT1000