An Improved Grinding or Pulverizing Mill.
Year: 1891

page_text: Date of Application, 20th Apr., 1891
Complete Specification Left, 22nd Feb., 1892-Accepted, 26th Mar., 1892
PROVISIONAL SPECIFICATION.
An Improved Grinding or Pulverizing Mill.
I, WILLIAM HENRY COWARD of Newark House, Railway Place, Bath, in the
County of Somerset, Engineer, do hereby declare the nature of this invention to be
as follows:-
My invention relates to an improved mill for grinding or pulverizing ores and
other hard substances; and it consists essentially in the combination, with a
cylinder rotating on a horizontal axis and provided with internal pockets or cups,
(as described in the Specification of previous Letters Patent dated the 27th day of
March 1889 No. 5286) of a stationary shoe or grinding block resting upon the
internal periphery of the cylinder and fixed upon a shaft mounted in a swivel
bearing and pressed upon by a spring or weight, as described in respect of the edge
runner mentioned in any aforesaid Specification for which the grinding shoe is a
substitute, the shoe being prevented from rotating with the cylinder by an arm
fixed to the shaft. The grinding surface of the shoe approximately corresponds in
form to the circumferential curvature of the cylinder, the leading end of the shoe
being bevelled in such form as to conduct the material to be operated on between
the grinding surfaces. Both of these surfaces, which are preferably curved in the
transverse direction, the cylinder concavely and the shoe convexly, are fluted or
grooved in such manner that the grooves cross each other at about right angles so
as to render the grinding action more efficient.
Dated this 20th day of Auril 1891
W. H. COWARD.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.
COMPLETE SPECIFICATION.
An Improved Grinding or Pulverizing Mill.
1. WILLIAM HENRY COWARD of Newark House, Railway Place, Bath, in the
County of Somerset, 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:-
My invention relates to an improved mill for grinding or pulverizing ores and
other hard substances, and it consists essentially in the combination, with a cylinder
rotating on a horizontal axis and provided with three sets of internal pockets or
cups, of stationary shoes or grinding blocks resting upon the internal periphery of
the cylinder, said shoes being fixed upon shafts passing out through apertures in
the opposite sides of the cylinder and each mounted in a swivel bearing and pressed
upon by a spring or weight, the shaft being prevented from rotating by an arm
fixed to it and bearing on an abutment. The grinding surface of the shoe
approximately corresponds in form to the curvature of the cylinder, the leading
end of the shoe being bevelled in such form as to admit the material to be operated
on between the grinding surfaces which are fluted or grooved, to render the grinding
action more efficient.
The grinding surfaces of the cylinder are constructed in sections and the apertures
in the sides of the cylinder are closed by stationary covers to which are connected
the feed hopper and the exhaust respectively, as hereafter described.
Reference is to be had to the accompanying drawings, forming part of this
Specification wherein Figure 1 is an axial vertical section, and Figure 2 a transverse
vertical section, of the improved mill. Figure 3 is a face view shewing the lever

page_text: arms by which the grinding shoe is prevented from rotating and the spring by
which it is loaded.
A is the drum driven by peripheral spur gearing and supported by two sets
of rollers J, one set at each side, upon which rest the hollow trunnions I at the two
sides of the cylinder. BB are the grinding shoes or blocks, each fixed on a shaft D
which passes through the hollow trunnion I of the cylinder and is anchored at the
outer end in a bearing E capable of swivelling on lateral gudgeons e pivoted in
lugs F so as to permit of angular motion of shalt D in a vertical plane. The shaft
is guided in this motion by a slide block in guides G and is pressed upon by a
spring I whose tension is regulated by screws. The rotation of the shaft is
prevented by lever arms K fixed rigidly to the shaft and terminating in set screws k
by which they may be made to bear accurately on the base plate.
9
As shown in the drawing, there are two of these grinding shoes resting side by
side within the cylinder and attached to separate shafts passing out through the
opposite trunnions I. The cylinder is provided with three sets of internal peripheral
cups CCC, the cups of the middle set C which pass between the grinding shoes,
being twice the size of those of the side sets C C.
The grinding faces of the shoes are made of hardened steel with transverse
grooves towards the rear part of the grinding face, said grooves being set a little
(say 1 inch) out of square to avoid shaking the shoe too much and improve the
grinding action whilst the leading portion of the grinding face is longitudinally
grooved and bevelled as at to allow the material to get beneath it.
grinding faces are bolted to the shoe so as to be readily replaced when worn.
grinding surface of the cylinder is formed of transversely grooved chilled iron
segments let into grooves or seats reserved for them in the circumference of the
cylinder.
These
The
The shoe is bevelled and pointed at the back part B¹ so as to tip the material
falling on it into the cups. R is a shoot fixed above the shoc to convey the material
falling thereon to the front of the shoe.
The hollow trunnions I are closed by stationary covers fitting within them and
provided with apertures to give passage to the shafts D. Upon the one cover L is
a feed hopper M, whilst to the other cover is connected an inverted funnel shaped
spont communicating with an upwardly extending exhaust pipe P, so that air
drawn in at the hopper M will pass across the shower of partially ground matters
falling from the cups C C and out at the spout O. The air thus performs a
winnowing action and the upward direction of the spout causes everything but the
fine particles to fall back into the machine, so that no sieves are required to separate
the coarse from the fine matters.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what I
claim is.
1st. A grinding mill consisting in the combination with a drum provided with
sets of internal cups and with a transversely grooved peripheral grinding surface,
of a stationary grinding shoe fixed to a shaft passing out through a hollow trunnion,
said shaft being anchored in a pivoted bearing vertically guided and spring or
weight pressed and prevented from rotating by a lever arm bearing against a fixed
abutment, as specified.
2nd. The herein described grinding mill consisting of the drum provided with
three sets of cups, and two shoes placed side by side and fixed to shafts passing
through opposite trunnions anchored, guided, loaded and prevented from rotating,
as described.
Dated this 20th day of February 1892.
W. H. COWARD.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.