Improvements in Chucks for Drills and the like.
Year: 1893

page_text: Date of Application, 9th May, 1893
Complete Specification Left, 9th Feb., 1894-Accepted, 10th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Chucks for Drills and the like.
1, CARL SCHARENBERG, Manufacturer, of 31 Fuerbrengerstrasse, Berlin, in the
Empire of Germany, do hereby declare the nature of this invention to be as
follows:-
This invention for improvements in chucks for drills and the like has for its
object to construct a chuck which shall be readily adjustable for wear, convenient
to manipulate, of great simplicity, of small cost, and certain in action.
In a chuck constructed according to this invention the jaws, of which there are
preferably three-slide in cylindrical and radial holes in the front part of the jaw
box which is bored out large enough to receive the largest article to be clamped.
Wedge shaped grooves or cam races are cut in the sides of the jaws and work in
conjunction with eccentric wedge shaped projections on the end face of an operating
head which is adapted to rotate on the centre part of the jaw box and is retained in
position by the enlarged front part of the jaw box and a nut screwing on the back
part of the jaw box and secured by a set screw. The back part of the jaw box is
coned axially to receive a coned driving pin formed with a shoulder so that by
screwing the nut back against the shoulder the chuck is forced off the driving pin.
The wedge shape of the operating surfaces admits the parts being readily adjustable
for wear as the projections do not extend to the bottoms of the grooves. The
operating head is rotated by a suitable key.
Dated this 9th day of May 1893
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Chucks for Drills and the like.
I, CARL SCHARENBERG, Manufacturer of 31 Fuerbrengerstrasse, Berlin, in the
Empire of Germany 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 for improvements in chucks for drills and the like has for its
object to provide a chuck which shall be certain in action and convenient in
manipulation and readily adjustable for wear of the clamp cheeks besides being of
greater simplicity and of less cost.
The chuck is shown on the annexed drawing:-
Fig. 1 shows an elevation (view).
Fig. 2 is a cross section on the bent line y-y of Fig. 3.
The remaining figures show details.
The tool consists essentially of the jaw box a the three jaws bb b, the ribbed
operating head c and the clamping nut d. The jaw box a is provided with the
three radial bored holes e which are equidistant from each other and serve for the
reception of the jaws b. At the lower part there is a central hole f to receive
the drill and at the upper part a thread h is cut and a conical boring h' in which
fits the head of the spindle i. The clamping jaws (Figs. 2, 3 and 7) are short
cylindrical pieces of steel of round or other section, the inner ends 6' of which are
[Price 8d1

page_text: wedge shaped and which are also provided on their upper surface with wedge
shaped eccentrically cut grooves b². The head c has on its under surface three
eccentrically arranged, and in section, wedge shaped ribs k, k, k, which engage in
the grooves 6 of the clamping jaws. The operating head c fits loosely on the
threaded spindle of the jaw box and is then, by means of the clamping nut d
which is screwed on the thread, pressed firmly by its ribs in the grooves of the
jaws. The clamping nut itself is fastened by a set screw l. With small chucks
one groove for each jaw is sufficient; with larger ones two are used. In
accordance therewith the ribbed body e carries three or six ribs; in the latter case
each two ribs are concentric to each other.
In order to clamp a drill of any desired size the ribbed body is turned axially by
a suitable key, so that by virtue of the eccentric direction of its ribs k, the jaws b
are forced out of the jaw box a. The drill g is then inserted in the opening f
and the operating head c turned hack tightly by the same key. The edges of the
wedge shaped clamping jaws 6' are thereby pressed against the shank of the drill
which, by ineans of their radial and vertical position, is clamped quite centrally and
perfectly securely.
g
In this chuck the ribs k do not fit quite to the bottom of the grooves 6*. Should
therefore after long usage any wear of the side surfaces of these grooves and ribs
take place a firm contact between the two can at once be effected by loosening the
set screw slightly and screwing up tightly the clamping nut d by means of the
before mentioned key, thus forcing the ribbed body deeper into the grooves b².
The spindle fitting into the bore of the threaded shank, and which connects
the chuck with the machine, is provided just above its conical end and over the
clamping nut d with an enlarged shank so that by turning the nut against it the
-chuck may be easily loosened. This has hitherto been effected by striking the side
with a hammer which, in the case of firmly fixed spindles, could not always be done
without damage, that is, bending the material.
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
.ciaim is :-
1. A chuck for drills and the like comprising jaws b actuated by a rotating
-operating head c provided with eccentrically arranged ribs k working in the
grooves b for their reception, made deeper than the ribs and wedge shaped, with
the object that by means of a clamping nut the operating head, and thereby the
jaws, may after tightening be still more firmly clamped, and also that with any
wear an adjustment by the clamping ring may be effected.
2. The use with the chuck described under Claim 1 of a nut d with a set screw l
for the adjustment of the operating head c and the loosening of the carrying
spindle i.
Dated this 9th day of February 1894.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.