IMPROVEMENTS IN GRINDING OR CRUSHING MILLS
Year: 1884

page_text: I JOSEPH THOMAS ANDREWS of Tottenham in the County of Middlesex Engineer
do hereby declare the nature of said Invention for "IMPROVEMENTS IN GRINDING
OR CRUSHING MILLS" to be as follows:→
My Invention relates to that description of grinding mill in which corn and
other substances are ground between a hard metal rotating grooved or fluted
grinding roller or barrel and a stationary concave surface of like material and
consist principally in an improved construction of the concave and in the means
or mode of regulating or adjusting the distance between the grinding surfaces.
In carrying out my Invention I employ a conical or tapered grinding or crushing
roller or barrel similar in construction to those usually employed and keyed on a
shaft or spindle rotated in the ordinary manner but instead of employing therewith
a concave or stationary grinding surface of a uniformly tapering form from one end
to the other as at present I employ a concave which is uniformly tapered for only
a portion of its length from the delivery end towards the feeding end of the mill
the remaining portion (i.e. that at the feed end) however not being parallel with the
grinding roller but being such that a tapered space is provided between the roller
and the concave at the feeding end of the mill which will readily admit of the
material to be crushed or ground entering between the grinding surfaces The
distance between the grinding surfaces is regulated or adjusted by a longitudinal
movement of the concave or the barrel or both which may be effected by the
following arrangement. I mount the concave on the frame of the mill so as to
rendor it capable of being slidden or moved longitudinally in the direction of the
axis of the grinding roller. This movement of the concave may be effected by
meaus of a rack fitted to or formed on the concave and made to gear with a pinion
fast on a shaft or spindle mounted in a bearing or bearings in the frame of the mill
and provided with a hand wheel or other convenient means for imparting rotatory
motion to the said pinion. Or instead of sliding the concave longitudinally tho
grinding roller may be moved along its spindle or the spindle itself be adjusted
longitudinally in its bearings or if desired both the roller and the concave may bo
made adjustable longitudinally. The bearing of the concave on the roller at each
end is made parallel with the shaft through a distance equal to the extent of travel.
The delivery end of the concave is provided with a spout which when the concave
is moved slides along a stationary spout or shoot fixed to the frame of the
mill thereby preventing waste of the ground material. In order to facilitate the

page_text: mounting of the grinding roller truly on its shaft and also to reduce friction I
provide the roller with soft metal bushes which may be readily bored out to fit
the shaft truly. These bushes may be made to project outside the ends of the
roller so as to rotate against the frame of the mill instead of causing the ends
of the roller to bear against the frame or cover as is usually the case, whereby
friction is greatly reduced and when the bushes become worn they may be readily
renewed.
Instead of providing the usual separate apparatus between the feeding hopper
and the cover of the grinding roller for separating extraneous substances from the
material to be ground I provide the feeding hopper, with a feeding shoe containing
a perforated plate upon which the material placed in the hopper falls and to which
a shaking or jogging motion is imparted from the spindle of the grinding roller by
means of a cam or eccentric and suitable connecting rods. The material is thus
fed to the mill in regulated quantities whilst any nails or other foreign substances
pass over the perforated plate and is guided thence down a spout or shoot to the
exterior of the mill.

page_text: COMPLETE SPECIFICATION,
I JOSEPH THOMAS ANDREWS of N° 16 Catherine Grove Devonshire Road
Greenwich do hereby declare the nature of said invention for "IMPROVEMENTS
IN GRINDING OR CRUSHING MILLS" 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 that description of grinding Mill in which corn and
other substances are ground between a hard metal rotating grooved or fluted
grinding roller or barrel and a stationary concave surface of like material and
consists principally in an improved construction of the concave and in the means
or mode of regulating or adjusting the distance between the grinding surfaces.
In carrying out my Invention I employ a conical or tapered grinding or crushing
roller or barrel similar in construction to those usually employed and koyed on a
shaft or spindle rotated in the ordinary manner but instead of employing therewith
a concave or stationary grinding surface of a uniformly tapering form from one end
to the other as at present I employ a concave which is uniformly tapered for only
a portion of its length from the delivery end towards the feeding end of the Mill
the remaining portion (i.e. that at the feed end) however not being parallel with
the grinding roller but being such that a tapered space is provided between the
roller and the concave at the feeding end of the Mill which will readily admit of
the material to be crushed or ground entering between the grinding surfaces The
distance between the grinding surfaces is regulated or adjusted by imparting a
longitudinal movement to the concave which may be effected by any suitable
mechanical means and for which purpose I mount the concave on the frame of
the Mill so as to render it capable of being slidden or moved longitudinally in the
direction of the axis of the grinding roller.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer
to the several figures on the annexed sheet of drawings the same lotters of reference
indicating corresponding parts in all the figures.
Figure 1 is a longitudinal horizontal section of so much of a grinding Mill as
will be necessary to illustrate my invention and Figure 2 is a transverse section
of the delivery end of the Mill.
A is the grinding roller fast on the shaft or spindle B which is fitted to rotate
in bearings in the framing C of the Mill.
In order to facilitate the mounting of the grinding roller truly on its shaft, and
also to reduco friction, I provido the roller with soft metal bushes which may be
readily bored out to fit the shaft truly. These bushes may be made to project
outside the ends of the roller so as to rotate against the frame of the Mill instead
of causing the ends of the roller to bear against the frame or cover as is usually
the case, whereby friction is greatly reduced, and when the bushes become worn
they may be readily renewed-This grinding roller rotates in a concave grinding
surface or counterpart D which according to my Invention is fitted to slide longitu-
dinally in the frame C, for which purpose it is provided with lugs or projections à d¹
bearing upon projections c c' on the said frame,

page_text: The longitudinal movement of the concave D may be effected by any suitable
mechanical means. I have shewn in my drawings a rack e, fitted to or formed on
the lug d' on the concave, and made to gear with a pinion f fast on a shaft or
spindle g mounted in a bearing h, on the frame of the Mill, and provided with a
hand wheel for imparting rotatory motion to the said pinion The bearing of the
concave on the roller at each end is made parallel with the shaft through a distanco
equal to the extent of its travel as shewn at a, and the grinding surface of the
concave from the delivery end to about the centre of its length is made of a
tapering form corresponding to the taper of rotating barrel A, whilst the other
portion of the surface towards the feeding end of the Mill is made of a different
taper whereby a tapered opening or space m is provided between the grinding
surfaces at the feeding end of the Mill to facilitate the entrance of the material
to be ground.
Instead of providing the usual separate apparatus. between the feeding hopper
and the cover of the grinding roller for separating extraneous substances from the
material to be ground I. provide the feoding hopper with a feeding shoe containing
a perforated plate upon which the material placed in the hopper falls and to which
a shaking or jogging motion may be imparted from the spindle of the grinding
roller by means of a cam or eccentric and suitable connecting rods. The material
is thus fed to the Mill in regulated quantities whilst any nails or other foreign
substances pass over the perforated plate and is guided thence down a spout or
shoot to the exterior of the Mill.
The delivery end of the concave is provided with a spout k which when the
concave is moved slides along a stationary spout or shoot b fixed to the frame of
the Mill thereby preventing waste of the ground material.
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
In mills for grinding or crushing corn and other substances the employment in
combination with a rotatory conical grinding barrel, of an adjustable concave
grinding surface or counterpart, constructed and arranged to operate substantially
in the manner and for the purpose hereinbefore described and illustrated by the
accompanying drawings.