An Improved Tool-holding Chuck.
Year: 1890

page_text: Date of Application, 17th Feb., 1890
Complete Specification Left, 11th Nov., 1890-Accepted, 13th Dec., 1890
PROVISIONAL SPECIFICATION.
An Improved Tool-holding Chuck.
1, JACOB GUTMANN, of Frankfort-on-the-Main, in the Empire of Germany, do
hereby declare the nature of this invention to be as follows:-
My invention relates to chucks or holders for boring tools and has for its object to
obtain an easy as well as an accurate centreing for the boring tool.
In carrying out my invention I employ a sphere or ball having conical-shaped holes
of different sizes formed therein to receive the shank ends of boring tools of various
sizes. This ball is placed between two half bearings which are adapted to be drawn
together so as to tighten them upon and grip the ball after the tool has been properly
centred.
Dated the 17th day of February 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Tool-holding Chuck.
I, JACOB GUTMANN, of Frankfort-on-the-Main, 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:-
My invention relates to chucks or holders for boring tools and has for its object to
obtain an easy as well as an accurate centering of the boring tool.
In carrying out my invention I employ a sphere or ball having conical-shaped holes
of different sizes formed therein to receive the shank ends of boring tools of various
sizes. This ball is placed between two half bearings which are adapted to be drawn
together so as to tighten them upon and grip the ball after the tool has been properly
centred.
In order to enable the invention to be fully understood I will describe the same by
reference to the accompanying drawing which is a vertical section of my improved
tool-holding chuck.
B is the sphere or ball provided with a conical hole in which is fitted the shank of a
boring-bit A.
C and D are screw-threaded bearings in which the ball B is held.
The centering of the boring-bit can be effected by knocking against the boring-bit
after it is set in motion or by putting the boring-bit into the punch mark of the object
to be perforated when it will centre itself.
In order to allow of the lateral adjustment of the boring-bit an opening G of
suitable diameter is provided in the lower half D of the bearing.
When the centering has been effected the ball B is secured in position by screwing
the parts C and D of the bearing tightly together in order to prevent any movement
of the ball relatively to the bearing whereby power may be transmitted from the
spindle to the boring-bit.
The tightening up of the two parts of the bearing is effected by means of pins E F
which for that purpose are inserted into suitable holes in the two parts of the
bearing.
By means of my improved tool-holding chuck I can effect the absolutely accurate
centering of the boring-bit and am enabled to execute the most accurate work in boring
in a simple and expeditions manner.

page_text: In some cases the ball B is provided with several holes of different sizes for instance
with four holes arranged at an angle of 90°.
When the ball is made sufficiently large holes for a whole set of boring-bits can be
provided so t
that when it is necessary to insert a new boring-bit the ball B need only
be turned round until the hole which corresponds in size with the shank of the bit to
be inserted appears opposite the opening G and it is in view of this advantage that I
have termed my improved tool-holding chuck the "Universal boring chuck."
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
claim is
1. A chuck for holding boring-bits and for accurately centreing the same, com-
prising a hall provided with holes of various sizes for receiving the shanks of boring-
bits the said ball being arranged in bearings the two parts of which after the centering
of the boring-bit has been effected being adapted to be drawn together so as to prevent
any movement of the ball independently of the bearing, substantially as hereinbefore
described.
2. The manufacture and use of the improved tool-holding chuck, substantially as
herein before described and illustrated in the accompanying drawing.
Dated the 11th day of November 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.