U.S. patent number 3,645,458 [Application Number 05/006,842] was granted by the patent office on 1972-02-29 for vibrating grinding mill.
Invention is credited to Hideharu Tobe.
United States Patent |
3,645,458 |
Tobe |
February 29, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
VIBRATING GRINDING MILL
Abstract
A miniature grinding device for grinding small samples which
comprises an electrically driven vibratory structure including an
eccentrically weighted shaft, a frame supported on said shaft, one
or more cylindrical grinding chambers secured to said frame and an
axially aligned free-moving grooved rod or roller in each chamber,
each said rod having a size slightly less than the inside volume of
each chamber.
Inventors: |
Tobe; Hideharu (Meguroku,
Tokyoto, JA) |
Family
ID: |
26343275 |
Appl.
No.: |
05/006,842 |
Filed: |
January 29, 1970 |
Foreign Application Priority Data
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|
|
|
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Feb 7, 1969 [JA] |
|
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44/8705 |
Feb 27, 1969 [JA] |
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44/16844 |
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Current U.S.
Class: |
241/175; 366/110;
366/209 |
Current CPC
Class: |
B02C
17/14 (20130101) |
Current International
Class: |
B02C
17/00 (20060101); B02C 17/14 (20060101); B02c
017/14 () |
Field of
Search: |
;241/137,153,175,184,199,284,291 ;51/164.5
;259/DIG.42,56,75,91 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Spruill; Robert L.
Claims
I claim:
1. A grinding apparatus for producing a finely divided powder of a
sample material, comprising:
vibratable means operative to oscillate uniformly and including at
least one cylindrical chamber for reception of the material to be
ground, with a grooved rod axially disposed within said at least
one cylindrical chamber;
a platform operative to support said vibratable means;
spring means disposed between said platform and said vibratable
means so that the vibratable means normally rests on said spring
means in a position of equilibrium;
a pair of support means spaced apart from one another, each support
means comprising a rigid portion, a resilient beam extending in
both directions from said rigid portion, and a pair of rigid stands
for supporting the ends of said resilient beam, each support means
being disposed so that said resilient beams are parallel with a
rotary shaft, between the undersurface of said vibratable means and
said platform; and
said rotary shaft being a motor-driven shaft rotably supported
transversely with respect to said vibratable means, with an
unbalanced weight being disposed on said shaft.
2. A grinding apparatus according to claim 1 wherein said at least
one cylindrical chamber is separable into two parts by a joint of
elastic material having a T-shaped cross section.
3. A grinding apparatus according to claim 1 wherein said
vibratable means comprises first and second cylindrical chambers,
each chamber having a grooved rod axially disposed therein.
Description
This invention relates to miniature apparatus for grinding
relatively small amounts or samples of material into finely divided
powder, and more particularly to such apparatus for use on a desk,
in a chemical laboratory, a hospital, a school classroom, et
cetera.
A desk grinding mill of compact size is widely used, but the
mechanism is limited because of its small size, resulting in
difficulties in producing finely divided powder.
The present invention has solved the problems and disadvantages of
the known device, and has for its object to provide a grinding
apparatus for producing the finest powder of a sample material
effectively, regardless of its limited mechanism.
According to the present invention, there is provided a grinding
apparatus for producing a finely divided powder from a sample
material, comprising a vibratory structure arranged to oscillate
over a uniform cycle, one or more cylindrical chambers in which the
material is loaded for grinding, mounted in the vibratory
structure, and a grooved grinding rod or roller axially located in
each chamber and of a size slightly less than the internal volume
of each said chamber.
The invention will now be more particularly described by way of
example, with reference to the accompanying drawings, in which:
FIG. 1 is a plan view of an apparatus in accordance with the
invention, parts being broken away to reveal the internal
construction.
FIG. 2 is a front elevation of the apparatus illustrated in FIG.
1.
FIG. 3 is an end elevation of the apparatus illustrated in FIG.
2.
FIG. 4 is a plan view of a support for the apparatus constructed in
one piece.
FIG. 5 is a front view of the support illustrated in FIG. 4, parts
being broken away.
FIG. 6 is a schematic view of an example of a grooved grinding rod
constructed in accordance with the invention.
FIG. 7 is a Table of data, showing the differences in achievement
between the apparatus in accordance with the invention and prior
art apparatus.
FIG. 8 is a Rosin-Rammler Grain Distribution Diagram.
A vibratory frame 1 is supported on a base 12 by means of a coiled
spring 7 of relatively weak strength (FIG. 3). The entire weight of
the frame 1 concentratedly rests upon the coiled spring 7, and the
frame 1 is further provided with a pair of supports 8 of elastic
material, such as rubber, which supports are placed transversely at
each extreme side of the frame 1. Each support 8 advantageously
comprises a central rigid portion 9, (FIGS. 4 and 5), a resilient
beam 10 of square section horizontally extending in both directions
from the central portion 9, and a pair of stands 11 accepting the
resilient beam 10, the support per se being constructed in one
piece. The rigid portion 9 is securely fixed on the undersurface of
the frame 1, and the stands 11 are attached to the base 12, by
means of fastening screws 17 through bushings 18.
Transversely of the vibratory frame 1, a shaft 2 is rotatably
supported in bearings 4, which is driven by an electric motor 6
through a flexible coupling 5, and which is provided with an
eccentric weight 3, causing centrifugal motion when the shaft 2 is
driven.
A cylindrical chamber 13 in which the material to be ground is
placed, is detachably mounted in the vibratory frame 1 in parallel
with the shaft 2, the number of which chamber is determined as
appropriate. In the example illustrated, two chambers are provided,
each being placed in parallel with the rotatory shaft 2. Each
chamber 13 is supported with its bottom end held insertedly in a
ring-shaped projection 19 formed on the inside wall of the frame 1,
and the other end held by a fixing screw 14 arranged progressively
in relation to the chamber 13.
Preferably, the cylindrical chamber may be separable into two
parts, coupled by means of a joint 20 of elastic material having a
T-shaped cross section. The fixing screw 14 is prevented from
undesired relaxation by means of a coiled spring 22, and a handle
21 is provided so as to secure and release the cylindrical chamber
13.
Located in each chamber 13 is a grooved rod or roller 15, the
groove 16 being axially engraved on the surface of the rod, as
illustrated in FIG. 6. The grooved rod 15 is located in the chamber
13 in coexistence with the material to be ground into powder.
Modifications to the grooved rod specifically described and
illustrated can be of course made without departing from the
invention. For example, other forms of groove, such as a helix,
could be engraved. In the example illustrated the rod 15 has six
straight line grooves 16 which are parallel with each other.
Regardless of the form of grooves, the rod or roller per se is
required to be situated in parallel with the shaft 2.
The operation of the invention is as follows.
The motor 6 is energized to rotate the shaft 2, causing the frame 1
to fluctuate substantially at uniform cycle by dint of the
centrifugal action brought about by the eccentric weight 3 on the
shaft 2, whereby the material contained in the cylindrical chamber
13 is frictionally ground by impact of the grooved rod 15 against
the inside wall of the chamber, the groove serving as pockets for
the material.
The vibratory frame 1 concentratedly rests upon the coiled spring 7
with equilibrium, and is further provided with the supports 8 on
each extreme side, particularly supported by the resilient beams 10
arranged in parallel with the rotary shaft 2, so that the resisting
force of the supports 8 is substantially uniform at any selected
time, in relation to the centrifuging force applied to the frame 1,
thereby imparting to the frame 1 the stable vibrations of uniform
cycle, and hence the material is effectively compressed and reduced
to powder between the inside wall of the chamber 13 and the grooved
rod 15.
The chamber 13 consisting of two separable parts will be of
particular value in the case when the powder thus produced is
removed from the chamber, thus eliminating the problem of product
residues in the chamber 13.
The remarkable advantages of the invention are seen from the
contrasted data shown in FIGS. 7 and 8. The data shown in FIG. 7 is
derived from the experiment in which the grinding apparatus employs
a rod having six straight line grooves as illustrated in FIG. 6,
whereas the contrasted data is from the apparatus using a
grooveless rod, i.e., a cylinder-shaped rod. It is evident that the
apparatus according to the invention is predominant when the
conditions are the same. In FIG. 8 the Rosin-Rammler Grain
Distribution Diagram is shown, in which the material is quartz
(SiO.sub.2) of 10 g. respectively, the particulars of which are as
follows:
Graph Kind of Apparatus Working Hours (min.)
__________________________________________________________________________
I motor-driven mortar 20 II manual mortar 12 III apparatus
according to the invention 0.5
__________________________________________________________________________
In the graph depicted, the Y-axis is "multiplied weight on a net,"
expressed in percentage, and the X-axis is "degree of grain" in
terms of micron.
It follows from the graphs that the apparatus according to the
invention can produce more finely divided powder in a shorter
period of time than any other.
As has been described and illustrated, the apparatus according to
the invention comprises a vibratory frame arranged to fluctuate
over a uniform cycle, one or more cylindrical chambers in which the
material is loaded for grinding, the chamber being mounted in the
vibratory frame, and a grooved rod axially located in each chamber,
and, as a result, it is adapted for accessible use, such as on a
desk, in a chemical laboratory, a hospital, a school classroom, et
cetera, particularly ensuring that it can grind a small amount of
material into fine powder.
The advantages of the present invention, as well as certain changes
and modifications of the disclosed embodiment thereof, will be
readily apparent to those skilled in the art. It is the applicant's
intention to cover all those changes and modifications which could
be made to the embodiment of the invention herein chosen for the
purposes of the disclosure without departing from the spirit and
scope of the invention.
* * * * *