Improvements in Grinding, Crushing, and like Machines.
Year: 1898

page_text: Date of Application, 2nd July, 1898-Accepted, 6th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in Grinding, Crushing, and like Machines.
I, CARL HOFMANN, of 66, Klosterstrasse, Breslau, in the German Empire, Mer-
chant, 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 grinding, crushing, and the like machines of the ball
and ring type, and its object is to construct a machine which will have great
efficiency and which will maintain its efficiency unimpaired even after a long
period of work.
The improved machine is illustrated in the annexed sheet of drawings which
will be referred to hereinafter, and in which Figure 1 represents the machine in
longitudinal section; Figure 2 shows it in transverse section; and Figure 3 is a
view of one of the balls.
The frame work and the driving mechanism of the machine may be the same
as is usually employed in grinding machines of a similar type.
a is a casing consisting of two side plates between which the ring c is securely
held in place. Contained within the casing and capable of rotating therein is a
vertical disc or wheel b provided with a convenient number of pockets compart-
ments or recesses d. The balls e are placed within alternate compartments.
Upon the rotation of the disc the empty compartments effect the mixing and circu-
lation of the material to be crushed while the balls in the alternate compartiments
effect the crushing, grinding or pulverising.
The balls'e are preferably of the oval shape shown in Figures 1 and 3, and the
inner surface of the ring c is correspondingly curved. I have found that these
oval balls wear very uniformly and retain their oval shape even after a long
period of hard work. In cases where spheres or cylindrical balls' have been
used it is found that they soon vary in shape, and that, consequently, the
machine, which has been constructed for a certain form of ball, has its efficiency
impaired.
In my improved machine, however, as the machine is provided at the start
with oval balls' which remain oval, the efficiency is not perceptibly decreased.
It is preferred to feed the machine at its highest point and periodically. This
may be done by the device illustrated. The hopper f is arranged over the
machine and contains the hollow rotary cylinder g which may be driven from the
main shaft q. This cylinder is slotted or is provided with an opening at one or
more points, so that when it occupies the position shown in Figure 2 it receives
material from the hopper. Upon the rotation of the cylinder the supply from
the hopper is cut off and when the opening h comes over the outlet 7 of the
hopper, the contained material is emptied into the machine.
The outlet i of the machine is arranged a little above the lowest point of the
machine so that some of the material is always in the casing and only that which
is properly ground or pulverised makes its exit.
If the machine is to be used for liquid or semi-liquid or fluid substances the

page_text: outlet will have to be arranged at a definite distance from the bottom.
plastic or dough like materials the outlet may be placed lower down.
For
When a material has to be ground into dust or to a fine powder a ventilator or
air propeller or blower may be arranged for circulating fresh air and for drawing
off the finished product. For this purpose the outer edge of the ring may
be channeled as shown at k, and the exhaust or opening through which the air is
drawn is arranged at 7 at the lowest point of the casing. The outlet i is of course,
dispensed with. Air and dust are drawn from the interior of the casing through
the opening o in the upper part of the ring, and pass through the chamber k
around the ring and out through the opening . The inlet for the material has,
in this case, to extend down to and almost in contact with the edge of the disc b.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In a crushing, pulverising, or similar machine of the type set forth, a rotary
dise provided with a suitable number of compartments of which alternate ones
contains balls or their equivalents, constructed and arranged substantially as and
for the purpose herein before described and as illustrated by the accompanying
drawings.
2. In a crushing, pulverising or similar machine of the type set forth, the com-
bination with a rotary disc of oval 'balls' substantially as and for the purpose
herein before described and as illustrated by the accompanying drawings.
3. A grinding, pulverising, or similar machine, constructed and arranged sub-
stantially as herein before described and as illustrated by the accompany drawings.
W. E. HEYS & SON,
Agents for the Applicant.