Improvements in Crushing and Pulverizing Mills or Machinery.
Year: 1897

page_text: Date of Application, 23rd Mar., 1897-Accepted, 8th May, 1897
COMPLETE SPECIFICATION.
Improvements in Crushing and Pulverizing Mills or Machinery.
I PETER BUTLER BRADLEY, of Hingham, County of Plymouth, State
of Massachusetts, one of the United States of America, Manufacturer, 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 that class of crushing or pulverizing mills wherein the
material is crushed by the impact of one or more rolls travelling upon an annular
die or ring, the roll having an axial rotation as well as a rotation about the vertical
axis of the ring or die.
In some instances the crushing effect is due entirely to the weight of the roll,
which travels over a substantially horizontal wearing face of the die or ring, and
in other instances the crushing is effected by the centrifugal force developed by
rotation of the roll or rolls within the ring or die.
This invention has for its object the production of a crushing mill wherein
advantage is taken of the weight of the roll and also of the centrifugal force
developed by its rotation, whereby the crushing effect due to the full weight
of the roll or rolls is very materially increased by the centrifugal force developed
thereby.
While it is preferable to use three rolls, as shown in the drawings, as thereby a
better balancing and more even operation of the mill is attained, it will be obvious
that I may employ more than three rolls, if desired, or I may use a less number,
without departing from the spirit and scope of my invention.
Fig. 1 is a top or plan view of a crushing or pulverizing mill embodying my
invention, the greater portion of three rolls being shown in dotted lines, the upper
part of the surrounding casing being omitted.
Fig. 2 is a vertical sectional view thereof taken on the line x-x, Fig. 1, and
Fig. 3 is a sectional detail showing the lubricating device for the roll supporting
spindle.
The circular pan or mortar A, having an upturned, substantially conical centre A¹,
is secured in suitable manner to a base or foundation A*, said pan or mortar having
an annular inwardly inclined face a shouldered at its inner lower circumference
at a', to form a seat for the annular die or ring B, which may be either continuous
or in section.
Between the ring or die and the circular wall a³ of the pan a continuous or
sectional wedge portion C is inserted, upturned at c to form a curb and secured by
suitable bolts e to the pan, rigidly retaining the ring or die B in its place on the
seat a.
The upper or wearing face 6 of the ring or die B is inclined inwardly and down-
wardly, as shown in Fig. 2, and forms a track for one or more crushing rolls D,
three such rolls being shown in Fig. 1.
As shown in Fig. 2, each roll is composed of a heavy, substantially concavo-
convex casting d, to the periphery of which a removable tire d' is secured by a.
retaining ring d² and bolts d³, though the rolls may be made of a solid casting if
more convenient.
The convex side of the central portion d of the roll is turned inwards, and the
roll as a whole is inclined towards the vertical axis of the ring or die, as clearly
shown in Fig. 2, the form shown for the interior of the roll being adapted to bring
the centre of gravity thereof as near the centre of the mill as possible.

page_text: ·
It is obvious that the nearer the centre of gravity of the roll is brought to the
centre of the mill, and the lower down such centre of gravity is located the greater
will be the force required to hold the roll erect, and consequently the mill can be
run at a higher speed than would be otherwise possible, and more of the centrifugal
force can be utilized in grinding.
This high speed is attained before there is any material pressure due to centrifugal
force brought upon the roll carrier, and up to this point all the centrifugal force can
be utilized in crushing.
Each roll is provided with an outwardly extended boss or hub d to receive a shaft
or spindle e upon which the roll rotates, the shaft having a collar e¹ to rest on the
internal shoulder d³ in the hub, while a ring do, shown in Fig. 2, as screwed to the
hub outside of the collar retains the roll in position on the shaft when the mill is
at rest or running slowly.
The outer end of the shaft or spindle e is extended into and through a rocking
head and reduced and threaded at e to receive a nut e* which holds the
shaft firmly in the head, and through the latter is passed a transverse trunnion
pin having bearings for its projecting ends in the bifurcated end of a
radial arm, oil ducts 8 being provided, closed by suitable screw plugs 9,
Fig. 2.
The trunnion pin fl is preferably at right angles to the shaft or spindle e and
in Fig. 1 is shown as headed at one end, and threaded.at the other to receive a
retaining nut f*, and the roll, shaft and head f can rock bodily on the trunnion
pin as a fulcrum.
The inclined position of the rolls towards the vertical axis of the mill render them
much more easily operated than would be the case if they were mounted on horizontal
or vertical shafts, and the centrifugal force developed by the rotation of the rolls
increases the pressure exerted upon the ring or die B, instead of being wasted in
friction as in the ordinary edge runner or Chilian mill.
Referring to Fig. 2, the central portion A' of the pan A has mounted therein,
in a long bearing 10 and a threaded bearing 15, a vertical standard or post g,
extended through a rotatable hub provided with one or more radial arms h, to each
of which a roll is pivotally connected or jointed as has been described.
At its lower end the hub his shouldered to engage the top of the bearing 10,
and a stirrup 2 shown in Fig. 2 as screwed upon the upper end of the hub, has
mounted therein a step ³ which rests upon the top of the post g and sustains the
hub and its attached parts, forming an end bearing.
To prevent the hub and its attached parts from rising, a collar g¹ is screwed
upon the threaded end 9² of the post g, and a lubricant may be admitted to
the step bearing by a suitable passage or duct 20 in the step ³ protected by a
cap 22.
Forged iron bars or links * are shown in Fig. 1 as interposed between the
arms and held in place by the trunnion pins f¹, to give the necessary strength
and rigidity to the revolving roll carrier, comprising the hub h¹ and its roll
carrying arms h.
A sheet iron web W is secured to the carrier arms enclosing the upper portion
of the rolls and serving as a hood to prevent the material from being thrown out
of the mill.
It is desirable to adjust on account of wear and to retain the rolls at about
the same angle when in operation, so that they will track or travel in the same
path on the die B, and herein I have accomplished this by raising or lowering the
roll carrier.
g
The post is threaded at 93 to engage the threaded bearing 15, and a worm-
wheel is secured to the post, in mesh with a worm gº, on a shaft 9 provided
with a suitable hand wheel g', Fig. 1.
By turning the shaft g" the post g will be raised or lowered the required amount,
and the carrier will be thereby adjusted as desired.
I have shown one of the links or bars has provided with an opening to

page_text: receive the shank * of a depending plow k, held in place by a suitable set
screw, the plow or stirrer acting to throw the material up onto the die B as
it rotates above the bottom of the pan A and within the die.
Obviously a plow or stirrer could be attached to each link, or to any other part
of the roll carrier, or the plow or plows may be dispensed with altogether.
A perforated screen S surrounds the mill, extending upwardly from the curb c
to the inclined casing M, which supports a suitable shield M₁ of any usual or
suitable construction, and outside of and a short distance from the screen S an
imperforate casing M2 surrounds the mill.
A feed chute K opens into, the interior of the mill, the screen S and shield M²
being brought up to the chute at each side, and suitably secured.
The material to be crushed is fed through the chute and falls upon the
die B, around which it is distributed by the action of the rolls, and by the plows
if used.
to
The roll carrier is provided with a driving pulley H, secured to the hub h¹,
which rotation is communicated by a belt, not shown, from a suitable source of
power, the carrier moving the rolls about the vertical axis of the mill, while the
rolls rotate on their own shafts or spindles e.
The material is crushed upon the die by the weight of the rolls and also by the
centrifugal force developed thereby, the jointed connections between the rolls
and roll carrier permitting the variation in inclination due to inequalities in the
grinding path.
The whole mass of material in the pan partakes of the rotary motion generated
by the rolls and is thrown outwardly against the screen S, through which those
particles sufficiently fine will pass, and if worked dry the screened material will
pass through openings 80, Fig. 2, into a pit or receptacle below the mill, the
shield M² preventing the escape of dust, etcetera.
If water is used the pulverized material which passes through the screen S will
be caught in the surrounding trough N, see dotted lines Fig. 2, and led away
through a suitable discharge spout N¹.
In the latter case the shield M2 is omitted and the openings 80 may or may not
be closed as desired.
Whether the wet or dry process be used the particles of material too coarse to
pass through the screen S will fall back into the mill to be again acted upon by
the rolls.
The arms h are provided each with a flange or shed he above and within the
trunnions f¹, to protect the latter from water or dirt which might run down upon
the inner side of the hood or web W.
In order to protect the head f and the parts adjacent thereto from flying material
or water it is surrounded by a curved shield S*, extending around the sides of and
beneath the head and enclosing the outer end of the hub d', while an end cap S₁
engages the outer end of the shield and rests its upper edge on the head, permitting
the latter to rock freely, the shield S* being attached to the arm h.
If the cap S¹ be removed a current of air will be drawn in at the outer end or
opening of the shield S*.
This current is due to the fact that rotation of the radial arms of the driver
causes, by their fan like action, air to be forced outwards within the shield M', and
into the outer open end of the shield S*.
Not only this, but the rotation of the roll about the spindle causes a suction at
the inner, lower end of the shield S*, aiding in drawing the current of air inwards,
and the current passes out at the inner end of the shield, effectually keeping all
dust away from the working joints and journals about the head.
It is necessary to lubricate the roll shafts or spindles e and in Fig. 2 I have
shown in dotted lines a convenient mode of supplying lubricant, the same being
shown in section in Fig. 3, the spindle e being bored throughout its length at es,
into which a solid lubricant in stick form as L50 is inserted, the lubricant being
pressed towards the inner end of the spindle by a spring s.

page_text: As shown in Fig. 3, I attach a loose plunger or pistons to the lower end of the
spring to bear against the lubricant.
A screw plug in the outer end of the spindle maintains the spring in place,
and as the lubricant melts little by little the expansion of the spring s continually
urges it forward.
Other means for lubrication may be employed if desired but I have found that
the means herein shown and described are very efficacious and avoids waste of
lubricating material.
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 I
claim is :-
1. In a crushing machine, a rotatable carrier having a radial arm, a rocking head
mounted therein, a spindle extended inwardly from the head, a curved shield
extended around the sides of and beneath the head, a removable end cap mounted
on the end of the shield, and enclosing the outer portion of the head, permitting
the latter to rock a roll on the spindle, and an annular die upon which the roll
travels, substantially as described.
2. In a crushing mill, a rotatable carrier, a rocking head mounted thereon, a
spindle secured to the head and having a longitudinal bore to receive lubricant,
means to force the lubricant towards the inner end of the spindle, and a roll
mounted rotatably on the spindle, substantially as described.
3. In a crushing mill, an annular die, one or more rolls adapted to rest and travel
thereupon, and a rotatable carrier for the rolls having mounted fixedly thereupon a
conical closed portion extending outside of the rolls and towards the outer ends of
the axes thereof to prevent scattering of the material during the operation of the
mill, substantially as described.
4. In a crushing mill, a rotatable carrier having a radial arm, a spindle pivotally
connected at its outer end with said arm, a roll rotatable on the spindle, an annular
die upon which the roll travels, and a curved shield extending beneath the spindle
between the roll and the arm and attached to the latter, the rotation of the carrier
and the roll inducing a current of air through the shield, to keep the working parts
free from dust, substantially as described.
5. In a crushing mill, an annular die having an inwardly and downwardly
inclined upper face, a roll inclined towards the centre of the mill and adapted to
rest and travel upon said face, and having its inner side convex to thereby bring
the centre of gravity of the roll low down and near the centre of the mill, to relieve
the strain upon the roll support and increase the pressure upon the die, and means to
support the roll and carry it around the die, substantially as described.
6. In a crushing or pulverizing mill, a rotatable carrier having a radial arm,
a rocking head mounted in said arm, a spindle extended inwards from the head, a
protective shield for said head and spindle, and rigidly attached to the arm, the
shield surrounding said head and spindle, a roll rotatable about the spindle, means
to retain the roll thereon, and an annular die upon which the roll rests and is
adapted to travel, substantially as described.
7. In a crushing mill, an annular die having an inclined upper face, a roll
adapted to rest and travel upon said face, the body portion of the roll being
concavo-convex, the convex surface being inward, and inclined towards the centre
of the mill, to thereby bring the centre of gravity of the roll low down and near
the centre of the mill, and means to support the roll and carry it around the die,
substantially, as described.
Dated the 22nd day of March 1807
WM. BROOKES & SON,
55 & 56 Chancery Lane, London, Agents for the Applicant.