Improvements in Pulverizing Machines.
Year: 1897

page_text: Date of Application, 20th July, 1897 --Accepted, 20th Nov., 1897
COMPLETE SPECIFICATION.
Improvements in Pulverizing Machines.
I, JOHN CALHOUN CLARK, Manufacturer, residing at Atlanta, in the County of
Fulton, State of Georgia, United States of America, 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 certain new and useful improvements in crushing mills,
and it consists substantially in such features of construction arrangement and
combinations of parts as will hereinafter be more particularly described.
The invention has reference more particularly to that class of crushing mills
in which suspended rods or shafts having crushing rollers at their lower ends are
operated to swing outward by centrifugal force to effect a crushing of the material
between the surfaces of the rollers and that of a ring or disc supported in an
adjacent position within a pan or basin wherein the rollers are supported. The
object of the present invention is to provide an increased effective crushing
surface in mills of the same size as heretofore, as well as a more perfect and rapid
crushing of the material. A further object of the invention is to simplify and
cheapen the cost of the mill, to materially lessen the wear of the parts and to
render the mill of easy control. These objects are attained by the means illus-
trated in the accompanying drawings wherein Figure 1 is a vertical elevation in
part section of a centrifugal crushing mill constructed and arranged in accordance
with this invention.
Figure 2 is a top plan view of the revolving plate or disc from which the roller
shafts are suspended, three of such shafts being represented in position thereon.
Figure 3 is a transverse sectional view of the said revolving plate or disc.
Figure 4 is a sectional plan view on the line - Fig. 1; and
Figure 5 is an enlarged part sectional view in detail of one of the crushing rolls,
showing the manner of fastening the plow to the underside thereof, & Fig. 6 is
an enlarged view of the bearing of the shaft 30, hereinafter referred to.
This improved crushing mill is capable of a great many different embodiments,
but for all general purposes it has been found that the construction and arrange-
ment of parts substantially as herein shown fully answers the purposes and gives
good results in practice. Thus 1. represents an ordinary pan or basin of suitable
depth and diameter, and which is provided interiorly with an annular rim or
shoulder 2, upon which partially rests the underside of an annular grinding ring
or die 3, that is held in place by means of fastening screws 4, passing
through the side of the basin at intervals and entering the said ring or die as
shown. These said screws 4 first pass through the wall of an outer casing 5
surrounding the pan or basin 1 so as to leave an intermediate space or chamber 6.
The said outer casing is supported in position upon suitable masonry or other
support at 7, and it is held in rigid position by means of rods 8, passing through
a flange 9 of the casing, and extending down and secured to a suitable base (not

page_text: shown) or otherwise.
Fitting into suitable threaded openings formed in the
upper edge of the outer casing at intervals, are the vertical rods 10, the lower
ends of which are threaded at 11 to screw into said openings and to the upper ends
of which rods the nuts 12 are applied. Surrounding each rod is a shell or tube 13,
the lower end of which rests upon the upper edge of the outer casing 5, and the
upper ends of these tubes or shells serve to receive and support an upper annular
ring 14, through which the upper ends of the rods 10 pass.
Depending from the said ring 14 is a screen 15 of suitable fineness and the
lower edge of which is secured to a flange 16 projecting from the upper edge of
the pan or basin 1; and surrounding the screen so as to leave an intermediate
chamber 16 is a thin metal cylinder or shell 17 extending all round the mill, as
does the screen and intermediate chamber. Thus is formed or constituted a
chamber which practically is a part of the space or chamber 6, between the basin
and the outer casing 5, and it will be understood that the fine material which
results from the crushing or grinding action of the rollers in the basin, passes
through the screen 15 into the chamber 16, and thence down and out through
the space or chamber 6, into a hopper 18 the lower end of which is in communica-
tion with any ordinary screw conveyor 19 for conducting the material away, to
any place desired. An exhauster communicates with a passage of said con-
veyor to any place desired. The construction and arrangement of parts thus far
described is substantially the same as has been used in crushing mills of former
construction, and while this or some equivalent embodiment is practically essential
to a proper working of this invention, it will nevertheless be understood that
it is not limited thereto in any manner whatever.
I will now proceed to describe the invention, and while certain preferred
embodiment of devices will be described it will be understood also that the inven-
tion is not limited to the details of construction and arrangement thereof. The
main purpose is to increase the grinding surface or capacity of the mill, and to
effect which is employed the simplest means possible, commensurate with strength
and rapidity of operation. Similarly as in some former mills of this type is
employed in line with the centre of the pan or basin 1, a vertical main operating
shaft 20, that is suspended in an upper bearing 21, and which passes through a
guide-bearing 22 and to this shaft rotation is imparted through the medium of
bevel gear wheels 23, 24, and a suitable driving shaft. Keyed or otherwise
secured to the said main shaft 20, so as to bring its upper surface about flush
with the upper surface of the ring 14, is a circular plate or disc 25 the diameter
of which about equals the inner diameter of the pan or basin 1 at its upper edge,
so as to enable the said plate or disc to rotate with the shaft 20 and just clear
the inner edge of the said upper ring 14. Pendant from the plate or disc where
it surrounds the main shaft is a sleeve or hub 26 which furnishes an extended
bearing and strengthens connection between the two, and the lower edge of the
said hub rests upon a collar 27 secured to the shaft at this point so as to maintain
the hub and disc in proper vertical position. The underside of the said plate
or disc is provided with radial strengthening ribs 28 which at their inner ends
are deep enough to extend to the lower end of the hub, but which gradually taper
off toward the edge of the disc as shown. The said circular plate or disc is
employed in this invention, as a support for the rods or shafts 30 of a series of
groups of grinding rollers 31, between the surfaces of which as well as the surfaces
of some of them and the grinding ring or die 3, the material is thoroughly and
effectively crushed or reduced. Each group of crushing rollers may be constituted
of any desired number, more or less as may be desired, and in this respect it will
be noted that I do not restrict myself.
For convenience of illustration I have shown three rollers to a group and have
shown three groups thus making nine rollers in all. It is the purpose in operation
that the periphery or grinding surfaces of the rollers of each group shall operate
against or upon each other to grind the material and that the surfaces of the outer
rollers a of each group shall also operate against or upon the grinding ring 3 at

page_text: the same time. To effect this action the outer rollers a of the several groups must
be carried outward against the ring 3 by centrifugal force, and in like manner
the inner roller b, of each group must be carried outward against the outer rollers
in a similar way, so as to constantly maintain the proper grinding effect. The
shafts 30 of each grinding roller 31, could be suspended from the circular plate
or disc 25 in many different ways and through the medium of variously con-
structed devices, and still be within the scope of this invention.
In order to enable the said devices (which will presently be described) to be
used as well as to effect the proper relative arrangement of the shafts and the
rollers, the said circular plate or disc is formed with a suitable number of equi
distant radial slots or openings 32 extending inward from the edge of the disc
to a point about midway between the central axis thereof; and also with half as
many similar slots or openings 33, each disposed in a position intermediate of two
of the first so as to alternate therewith, and being set back from the said first
named slots or openings with their inner extremities reaching quite near to the
central opening of the disc. Each of the said slots or openings 33, has leading
thereto in a direct line from the edge of the disc a narrower slot or opening 34,
to permit insertion of the shaft of the inner roller of each group prior to the
placing in position of the shafts of the outer rollers of the several groups. Imme-
diately adjacent the edges of each of the said slots or openings 32 and 33 the
plate or disc 25 is provided with a lug or projection 35, and between each pair
of these lugs are formed the threaded openings 36, which receive the ends of
screws 37, that secure in place the removable cap plates 38 which in part con-
stitute the bearings 381 for the trunnion-pins 39 resting on either side of the
openings 32 and 33 and serving as the swinging support of the shafts of the rollers.
The preferred devices for supporting the upper ends of the shafts, to which general
reference has heretofore been made, will now be specifically referred to. Supported
in each of the slots or openings 32 and 33, is a swinging cylindrical box 40 that
is formed a short distance from its upper end with an internal shoulder 41, and
which is enlarged or off-set at one side at 42 to produce a thickened portion through
which the said pin 39 passes with its ends resting in the bearings 381, as explained..
Each of these swinging boxes is bored out to receive a hollow brass 43 with a
flange 44 at the upper end resting upon the shoulder 41 within the box and upon
the upper end of the brass is an annular bearing surface (preferably a ball bear-
ing) 46, for the head 47 of the shaft 30. As shown there is an under facing
beneath the head of the shaft, consisting of a cast iron ring 48 which rests upon
the top of the brass; and also as shown, the internal diameter of the swinging
box at the top is sufficiently enlarged at 49 to slightly more than accommodate
the shaft head, and thus to form an oil-chamber above and surrounding the
said head. The cap 50 of the chamber is held in place by screws 51, and passing
through the cap centrally of the chamber but slightly out of contact with the
head 47, is a cock-head bearing in the form of a screw 51' and nut 52. Within
the lower threaded end of the swinging box works a follower 53 that surrounds
the shaft 30, and which is used to bear upon and compress a packing ring 54
into the lower end of the box beneath the lower end of the brass. It' will be
seen that the oil in the chamber will flow down around the sides of the working
parts or bearings, and that it will be retained by the said packing.
The grinding rollers 31. may be of any suitable configuration, but they are
preferably slightly conical and they are secured to their respective rods or shafts 30;
and in any suitable manner so as to rotate with said rods or shafts independently
of the rotation of the central or main operating shaft. It is evident that when
the latter shaft is operated the outer rollers a of each group will be carried out-
ward to grind the material between their surfaces and the surface of the grinding
ring 3.
At the same time the inner rollers will be carried against the outer
rollers and effect a similar grinding action, and they also thereby multiply the
number of grinding points as well as greatly increase the area of grinding surface.

page_text: As before stated I am not limited either to the manner of roller groups or to
the number of rollers in a group.
Suitable plows are employed to stir up the material in the pan or basin, and
as a convenient form they are made substantially of the shape of a curved shoe 56,
one of them being secured to the underside or lower end of each roller by means
of short rods or bolts 57, having tightening nuts 58 on their upper ends.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. The combination in a grinding mill, of a grinding ring and a rotary group
of grinding rolls acting upon each other to grind the material, each roll adapted
to swing outward by centrifugal force, and the outer rolls of the group also acting
upon the ring, substantially as described.
2. The combination in a grinding mill, of a grinding ring, and a series of rotatory
groups of grinding rolls, the rolls of each group being adapted to swing outward
by centrifugal force and acting upon each other to grind the material, and the
outer rolls of each group acting upon the ring, substantially as described.
- 3. The combination in a crushing mill, of a grinding ring, and a series of groups
of crushing rolls suspended from a common shaft, and each roll carried by a
shaft rotatable in a swinging bearing, the rolls in each group operating upon one
another, and the outer rolls thereof operating upon the grinding ring, substantially
as described.
4. The combination in a crushing mill having a grinding ring or die of a
rotatable circular plate or disc, a series of groups of swinging boxes suspended from
said disc, and independently rotating shafts turning in said boxes and each carrying
at its lower end a roller, the said rollers in each. group operating upon one another,
and the outer rollers thereof upon the surface of the grinding ring, substantially
as shown and for the purpose described.
5. The combination in a crushing mill having a grinding ring or die, of a
rotating circular plate having a series of slots or openings extending inward from
the edge equi-distant from each other, and another series of similar slots or open-
ings alternating with and set in from the first, swinging boxes suspended through
said slots in suitable bearings, independently rotating shafts working in the boxes
and each carrying at its lower end a grinding roller, the said rollers operating
upon one another in series and upon the surface of the ring, substantially as
described.
6. The combination in a crushing mill having a grinding ring or die, of a
rotating circular plate having a series of slots or openings arranged at equi-distant
points and extending inward from the edge of the disc, and also formed with
another series of similar slots or openings alternating with and set in from the
others and having continuations extending to the edge, swinging boxes working
in said slots independently rotating shafts working in the boxes and each carrying
at its lower end a grinding roller, the said rollers operating upon one another in
series and upon the surface of the ring, substantially as described.
7. The combination in a crushing mill having a grinding ring or die, of a
rotating circular plate having sets of slots or openings formed therein with the
slots of one set intermediate of those of the other set, lugs or projections on the
disc adjacent the edges of the slots swinging boxes suspended in bearings confined
between the lugs on opposite sides of the slots, independently rotating shafts
working in the boxes, and grinding rollers carried at the lower ends of the shafts
and operating upon cach other and upon the surface of the grinding ring, sub-
stantially as described.
8. The combination in a crushing mill having a grinding ring or die of a series
of groups of grinding rollers suspended from a common shaft and each having an
independent axis and carrying at its lower end a plow, the said rollers operating

page_text: upon one another and upon the surface of the ring by centrifugal force, sub-
stantially as shown and described.
1007
BOULT & WADE,
Agents for the Applicant.