Improvement in Chucks or Face Plates for Machine Tools.
Year: 1895

page_text: Date of Application, 3rd Dec., 1895-Accepted, 11th Jan., 1896
COMPLETE SPECIFICATION.
Improvement in Chucks or Face Plates for Machine Tools..
I, FRIEDRICH ZINZEN, Mechanical Engineer, of 18, Wagnerstrasse, Düsseldorf,
in the German Empire, 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 appliances for fixing pieces of work concentrically in
Irilling machines and other machine tools. The object of the improvement is, to
fix pieces of work concentrically and securely in less time than can be done with
the means generally employed.
In the accompanying drawings
Fig. 1 is a side elevation, Fig. 2 a face view, and Fig. 3 an axial section of a
chuck embodying my invention.
Fig. 4 represents a modification.
The appliance chiefly comprises a circular plate a and cheeks k guided in the
said plate so as to be capable of approaching its centre or receding from the
same.
The said cheeks or claws k are provided with screw-nuts m through which pass
radial screw spindles s adapted to turn in bearings s¹ and s³.
The front or inner
end of each spindle s carries a small bevel-wheel z adapted to gear into the bevel
wheels of the adjoining spindles, so that by turning one of the screw spindles, the
said bevel wheels are caused to turn simultaneously in alternate directions; that
is to say, one to the right, the next to the left, and the next following again to
the right. Consequently, two of the screw spindles have right hand threads, and
the others left hand threads.
By thus providing the front ends of the spindles with bevel wheels gearing
into each other, the motion of the cheeks or claws is rendered simultaneous and
uniform; and the cheeks may be caused to advance from the circumference of the
disc towards the centre until they touch each other; consequently the face plate
can be used for very large and for very small pieces.
Although the drawing shows a chuck with 4 spindles and 4 cheeks, six or more
may be employed; but if they are all to be turned from the same centre, an even
number of spindles must be chosen, otherwise the tooth wheels would prevent them
from turning. If it is desired to use an uneven number of screw spindles and
cheeks, one or more of them must remain without a bevel wheel, or one or more
bevel wheels are set out of gear.
This case is represented by Fig. 4 which shows three screw-spindles. Two of
the cheeks are propelled towards the centre of the plate simultaneously, while
the third remains free and must be set separately. In this manner it is possible
to fix the piece of work concentrically to the chuck or face-plate, or excentrically;
and the use of a large toothed ring or of excentric grooves is avoided.
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 fastening or centering appliance for chucks or face plates, comprising in
its construction a set of screw spindles carrying at their inner extremities small
bevel-wheels ≈ gearing with one another, and cheeks provided with screw nuts m,

page_text: the said screw spindles having alternately right and left hand threads, the whole
being adapted and constructed to operate substantially as described with reference
to Figs. 1 to 3, and for the purpose specified.
2. A fastening or centering appliance for chucks or face-plates, comprising in
its construction two sets of screw spindles, one set carrying at their inner ends
small bevel wheels gearing one into the other so as to ensure the simultaneous
motion of the whole set, while the spindles of the second set can be turned
independently of the others, substantially as described and for the purpose
-specified.
Dated this 2nd day of December 1895.
FAIRFAX & WETTER,
433, Strand, London, Agents.