Improvements in Tool Holders for Boring, Drilling, and like Machines.
Year: 1897

page_text: Date of Application, 31st July, 1897-Accepted, 18th Sept., 1897
Improvements in Tool Holders for Boring, Drilling, and like
Machines.
I, CHARLES JUNGE, of Lincoln Chambers, 75 Chancery Lane, London, W.C.,
Consulting 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 relates to improvements in tool holders for boring, drilling,
shaping and like machines.
In the accompanying drawings,
Figure 1 shows an elevation of an improved tool holder;
Figure 2 is a plan,
Figure 3 a vertical section, and
Figure 4 a horizontal section of the same.
Figure 5 represents an elevation of the cutter holder, and
Figures 6 to 10 are cross sections showing the tool holder with cutters arranged
in various manners.
In the improved tool holder the turning power of the machine or of the breast
borer or drill is first transmitted to the co-axial screw S, which passes through the
locking nut M closing the upper end of the cylinder C which contains the cutter
holder B and acts against the head of the latter. The cutter holder is split up
lengthwise into several spring branches by a number of grooves or slots N which
are in connection with each other. Between these spring branches the cutters R
are retained.
In order to secure the cutters firmly to the holder, the latter is
provided on the lower part of its surface with sliding faces F which are gradually
reduced towards their lower end and work against corresponding inner guide
faces A at the lower end of cylinder C in such a manner that when screw S is
turned the spring branches of the holder B are forcibly pressed together, thereby
fixing the cutters immovably in the said grooves or slots N. The aforesaid sliding
faces prevent the cutter holder from turning in the cylinder C, so that we turning
power of the boring or like machine will be transmitted to the screw S, nut M
and cylinder C, while pressure is only exerted upon the cutter holder B to prevent
it, as before stated, from turning in the cylinder C and for securing the cutter..
The upper part of the spring branches of the cutter holder is weakened by faces L
in order to increase the elasticity of said branches.
As will be seen from Figures 6 to 10, the number, the arrangement and the
breadth of the cutters may be adapted to the work in hand; their breadth need
not be of the same diameter as the cylinder which carries the cutter holder, but
depends solely on the diameter of the holes to be bored or drilled.
When the improved tool holder for boring and shaping machines is to carry
only a single cutter, the latter is inserted as shown in longitudinal section
Figure 11, and in cross section Figure 12, not into the grooves or slots N, but into

page_text: the central bore connecting such grooves or slots. In order to increase the friction
between the inner wall of the bore and the surface of the cutter the latter is
suitably roughened.
The cutters, which may be moved forward in the improved tool holder in
proportion to the wear, are sharpened, for instance when there are three cutters,
by forcing two of them backwards into the holder and securing them in position
by tightening the screw S, thus enabling the single projecting cutter to be
sharpened without trouble; afterwards the other two may be sharpened in a
similar mauner. The improved tool holder is not only used for boring or drilling,
but may equally well serve for shaping and for countersinking holes. When used
for shaping gudgeons and conical ends, as represented by Figures 13 to 15, the
cutters should not work with their outer edge, but with their inner edge.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is:
An improved tool holder for boring, drilling, shaping and like machines, con-
sisting of a cutter holder B having a number of, spring branches with taper sliding
faces Fat the lower end, bearing against corresponding guide-faces A in the inner
side of the cylinder C receiving the said cutter holder and a co-axial, screw S
which passes through the lock nut M at the upper end of the said cylinder and
ncts against the head of said cutter holder, thus pressing the spring branches of
the latter together, substantially as herein described and shown in the drawings:
Dated this 30th day of July 1897.
sin
CHARLES JUNGE.