Year: 1887

page_text: Date of Application, 18th Oct., 1887
Specification Accepted, 13th Jan., 1888
I, JOHN JOHNSTON, of Hartford, Connecticut, one of the United States of America,
mechanical 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 :-
This invention is suitable for use in a lathe, or in a bolt cutter, or in a scrow
machine, or in a chucking machine, or in any other place where a chuck is required.
Figure 1, of the drawings, is a vertical longitudinal view of the chuck, showing
the upper half in diametric section. Figure 2 is a plan view of the chuck, showing
only the exterior thereof. Figure 3 is an exterior elevation of the face of the chuck.
Figure 4 is a vertical lateral section on the line x, x, of Figure 2. Figure 5 is a
perspective fragmentary view of the spindle, and of half the chuck plate, the other
half being a counterpart of the half shown, and being integral therewith, and being
united to the broken-away half of the bifurcated end of the spindle. Figure 6 is a
perspective view of the right hand half of the upper slide; and the left hand half is
a counterpart thereof, except that it has no place for a screw. The lower slide is a
counterpart of the upper slide. Figure 7 is a perspective view of the upper jaw;
and the lower jaw is a counterpart of it. Figure 8 is a longitudinal section of a
modified form of the sliding collar.
The numeral 1 indicates the spindle. It is bored through its axis, for the reception
of the rod or wire to be clasped by the chuck; and its end is bifurcated, and each of
those bifurcations terminates in two perforated lugs, as indicated in Figure 5. The
chuck plate 2 is cast with the spindle, and with the four lugs projecting forward from
its inner face, as far as the plane of its outer face. The collar 3 slides on the spindle 1,
and thus works the bell-crank lever 4, and a corresponding dever in the diametrically
opposite side of the spindle. These two levers are pivoted between the upper and
the lower pair of terminal lugs, of the spindle, respectively, and their longer ends
work between the bifurcations of the spindle being forced toward each other by the
inclined planes on the inside of the collar, and being forced from each other by the
spring 5, and a corresponding spring fixed in the opposite side of the spindle. The
shorter end of the lever 4 is pivoted between the links 6 and 6, and the other lever is
pivoted between two other corresponding links. The inner end of the link 6 works
in the socket in the ledge 7, of the upper slide 8, and the inner end of the link 6

page_text: works in a corresponding socket in a corresponding ledge on the other half of that
slide while the inner ends of the other two links work in corresponding sockets in
corresponding ledges on the lower slide 9. The jaws 10 and 11 are preferably provided
with the removable dies 12 and 13, which may have any form desired, and may be
changed at will. The right handed screw 14 turns with its unthreaded part in the
bearing 15 of the slide 8, and with its threaded part in the half-nut 16 of the jaw 10;
while the left-handed screw 17 turns in corresponding places in the slide 9, and the
jaw 11, respectively. These two screws are joined by a square tenon on the inner
end of one of them, and a square mortise in the inner end of the other, so as to turn
always uniformly together. The bushing 18 is preferably shrunk upon the bifurcated
part of the spindle 1, to provide a continuous journal for revolution in the journal
box 19.
The chuck plate 2 may be fixed to the spindle instead of being cast therewith; and
the four lugs, which furnish fulcra for the levers, may be integral with the chuck
plate, so that when the chuck plate is removed from the spindle, it will carry the lugs
and the levers along with it. The modified sliding collar shown in Figure 8, differs from
that shown in Figure 1 in having its working inclined surfaces adjustable to variant
degrees of inclination, so as to give a variable movement to the jaws. This end is
reached by providing a pivoted arm Figure 20, the inclined surface of which works
the lover 4, and which is adjustable to different inclinations by the set screw 21; and
by providing a duplicate of the same arrangement in the opposite side of the collar.
Instead of the lever 4 being pivoted between two links, it may have its shorter
end bifurcated, with the link 6 pivoted between its bifurcations, and working in a
socket in a ledge projecting from the middle wall of the slide 8, into the space
between those bifurcations. The corresponding levers on the other side of the chuck
may likewise be bifurcated and work but one link instead of two.
The mode of operation is as follows:-The jaws are adjusted to receive wires or
rods of variant sizes, by turning one of the screws and thus turning both of them, so
as to change the position of the jaws in the slides. When the jaws are open the slides
are slightly apart. Then the wire or rod is inserted in the jaws, and the collar is
moved by any proper means towards the chuck plate. That movement forces inward,
the longer ends of the levers, and thus forces the inner ends of the links to approach
each other, and to press the slides together into contact. The jaws are carried
with the slides and thus firmly clasp the inserted rod or wire between them. When
that article is to be removed from the chuck, the collar is moved back, and the
springs press the longer ends of the levers apart, and thus open the jaws.
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. The combination of the collar 3; the lever 4; the link 6; and the slide 8 ; all
constructed and arranged so that a movement of the collar depresses the slide;
substantially as described.
2. The combination of the slides 8 and 9; the jaws 10 and 11; and the screws 14
and 17; all constructed and arranged so that the jaws may be adjusted mutually and
equally, relatively to the slides, by turning either or both of the screws; substantially
as described.
3. The combination of a sliding collar, provided with two inner inclined planes ;
two bell crank levers, worked by that collar; two links, worked by those levers, and
two jaws worked by those links; all substantially as described.
fourth day of Santambar 1887