Improvements in Grinding Mills.
Year: 1891

page_text: Date of Application, 28th Sept.. 189:-Accepted, 14th Nov., 1891
Improvements in Grinding Mills.
We ALEXANDER MCGREGOR of Albion Iron Works Leigh in the County of
Lancaster Engineer, and HENRY BURCH of the same place Draughtsman, 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 has for its object improvements in that class of grinding mills in
which the grain or other material to be operated upon, is passed between two metal
discs; the one fixed to the frame of the mill, and the other secured to a horizontal
shaft and made to revolve at an adjustable distance from the fixed one; a portion
of such improvements being also applicable to mills which have a roller, or rollers,
instead of discs.
The nature of our said invention and the manner in which the same is to be
performed or carried into practical effect will be readily understood on reference
to the 9 sheets of drawings marked with figures and letters of reference corresponding
with those in the following explanation thereof.
According to the first part of this invention we construct the frame of the mill
in the manner shown in Fig. 1, Sheet 1 of the drawings and place the fly wheel U
between the bearings V and W, the bearing W being extended or carried inside
the driving pulley X almost to its centre in order to form a good support for same,
and the plate e¹ cast to or so secured as to form a part of the frame. Figs. 1B, 1º,
and 1P (Sheet 2) are elevations and plan view of the form of the frame so con-
structed; and a modification of the form but with the same object in view is shown
in Fig. 1, (Sheet 3).
The face of the plate e is rebated and turned, machined or otherwise truly
constructed so as to be an accurate support for the cover or case N, which
forms the grinding chamber, and has a concentric tubular bearing N¹, with
renewable pipe bushing P, for supporting the outer end of the main driving shaft c.
The next part of our invention (see Sheet 4 of the drawings) relates to an
improved construction of the grinding, rubbing, or cutting surfaces of the grinding
discs, with the object of rendering them more effective in operation, and at the
same time much more durable than the discs in ordinary use for that purpose.
On the flat, or slightly dished surface, of the ring or plate which forms the
grinding disc, (see Sheet. 4) are a series of raised zigzag ribs, radiating from the
central part to near the periphery, and having both sides square or nearly so
with the face of the disc. The top of these zigzag ribs forms one level surface
or nearly so having rectangular corners or cutting edges on either side of each
rib. When the edges on one side of the zigzag ribs are worn off, if the grinding
disc is made to rotate in the contrary direction, the opposite or sharp zigzag edges
come into operation. By the time these opposite edges are worn off, the first used
edges become sharpened and by again reversing the direction of motion, they are
brought into use. This change in the direction of the motion of the disc may be
continued until the ribs are almost worn down to the flat part of the plate.
In Fig. 1, Sheet 1, of the accompanying drawings, a represents the revolving
grinding disc, carried by the plate or wheel b, on the main shaft c, and facing the
stationary disc d which is fixed to the plate e previously described as forming part
of the main frame.
Fig. 2 Sheet 4 is an elevation of a grinding disc showing the arrangement of the
zigzag ribs; an enlarged scale section of a rib shown at f Fig. 4. The zigzag
form of the ribs may be at a greater or less angle than that shown in the elevation,
or the angles may be rounded off in the form of corrugations.
As a modification of this part of the invention we make use of a disc having a

page_text: series of raised rings on its face as shown in Fig. 24, which arrangement also
admits of the disc being made to rotate in either direction.
In order to still further add to the endurance of the grinding discs they may
be formed as shown in the half section Fig. 5, that is, with corresponding ribs on
both sides of the same plate so that when one side is worn away, the disc can be
reversed and the other side or duplicate set of ribs brought into action.
Although we have shown and described the zigzag ribs as having a square or
cutting edge on both sides we do not confine ourselves to this arrangement; and
the ribs may be formed with one edge rounded or bevelled-off and with only the one
side forming a cutting edge.
In order to assist in leading the material under operation to the grinding discs,
and at the same time to subject it to a preliminary crushing process we make use
of ribbed cones as shown in Fig. 3, Sheet 4, and 6 and 7 Sheet 5, the external
cone g being formed in one with the revolving disch and the internal cone i in one
with the fixed discj; the grain or other material to be operated upon, being fed in
through the opening k (Fig. 6) in the upper part of the fixed, or internal conc. Or
the cones may be made separate from the grinding discs and secured to the revolving
wheel and fixed plate independently, but in either case we prefer to form the ribs
on them in the manner shown in the drawings, so that they may be equally effective
in leading the material to the grinding discs when revolving in one direction as
when revolving in the other.
The ribbed discs may be used in conjunction with any other description of cone
or barrel; or the material to be operated upon may he fed direct into the central
opening of the disc without the intervention of cones or other preliminary breakers.
In order to facilitate the reduction of the grain or other material into flour, we
form the outer part of the discs, say for one eighth of an inch or more from their
periphery, of a series of fine radial grooves as shown in Figs. 2, 2 and 3, Sheet 4,
having a face level with the top of the zigzag or otherwise formed ribs; so that
the material after having been cut into fine particles by the action of the ribs is
rubbed into flour, before being finally discharged at the periphery of the discs.
The next part of this invention relates to the manner of feeding the grain or other
material into the grinding surfaces of the mill.
To the bottom part of the hopper n Figs. 1 Sheet 1 and 1³ Sheet 3 we form or
secure a swan-neck case o, surrounding the feeding spout p, and secured at the back
of the plate el. To the underside of this case o we form or fix a lug or boss 9 which
carries a pin r, on which is placed an upright levers, used for communicating a
reciprocating motion to the feeding spout p. In order to actuate this lever we
make use of an arrangement (shown separately in Fig. 14, Sheet 1) in which the
excentric t, which is placed loose on the main shaft c, is in such position as to be
always engaged with the upright lever s. On the side of this eccentric we form
clutch teeth or pins which gear into corresponding teeth or holes at the side of a
sliding clutch u, which has the rotary motion of the shaft imparted to it, but is
capable of being moved endways by a lever, or other suitable appliance, so as to
give motion to the eccentric, or not, as desired.
As a modification of the manner of actuating the lever, we sometimes make use
of an eccentric as shown in Fig. 12, Sheet 6, which has the same rotary motion as
the shaft, but is capable of being shifted endways on the same. We form one side
of this eccentric with a cone v, which tapers from the eccentric w, to a concentric
part so that by moving it endways on the shaft, either the eccentric or the con-
centric part may be brought into line with the upright lever, and the motion imparted
(or arrested) to the feeding spout.
In order to ensure the upright levers being actuated by the eccentric with as
little friction as possible, and at the same time without any backlash jar or looseness,
we form the part of the lever which engages the eccentric, of two pieces of spring
steel y or other suitable material one on either side as shown in Fig. 11; these
pieces being bolted or otherwise secured to the main part of the lever, and are
adjustable for wear and tear.

page_text: According to a modification of the arrangement for giving motion to the feeding
spout, we form or secure a tubular bearing A, Figs. 8 and 9, Sheet 6, on the under-
side of the case O, and make use of an upright shaft B, having an eccentric or
crank C, which fits into a hole in the underside of the feeding spout D; and by the
revolution of the shaft gives a motion to the feeding spout which corresponds with
the motion of the eccentric or crank C. In order to actuate this upright shaft we
make use of friction wheels, the one being a collar or roller E secured to the main
shaft of the mill, and the other in the form of a disc F, secured to or forming a
part of the upright shaft, and with its underside touching the periphery of the
roller E. In order to arrest the motion of the feeding spout we make use of an
eccentric lever G, or other suitable contrivance, so as to slightly raise the disc F,
and prevent the face of it from touching the roller E.
With the object of giving a fast or slow motion to the feeding spout, according
as may be best suited to the material which is being operated upon, the roller E,
can be moved endways on the main shaft, and thus engage with a larger or smaller
diameter of the face of the disc F.
According to a further modification of this part of our invention, we make use
of an arrangement shown in Fig. 10; and in addition to the vibratory motion given
to the feeding spout H, we make the outer end of the same capable of being raised
or lowered: and in order that the vibratory motion may cease when the feeding
spout is raised to its highest position, we form the crank 1, which actuates it
inclined, until its upper end becomes concentric with the upright shaft of which it
forms a part. The upright shaft may be placed under the feeding spout and driven
by friction wheels in the manner previously described; or it may be as shown
in Fig. 10, placed to the side of the feeding spout, and driven by a cord or other
suitable appliance.
It will be understood that the case o can be dispensed with and either of the
shaking arrangements be supported by a bracket or other suitable means.
The next part relates to the manner of adjusting the grinding surface of mills at
the proper distance apart for the work it is desired to perform. The main shaft C,
Figs. 1, Sheet 1, 1 Sheet 3, and 13 Sheet 7, is capable of being moved endways in
the ordinary manner and the revolving. disc is pressed towards the fixed one by
means of the adjusting screw J, forcing the wearing block K against the end of the
main shaft; the discs being forced apart by means of a spiral spring on the main
shaft. The screw box L, which carries the adjusting screw J, is kept in position
by the pressure of a pair of springs sufficiently strong to withstand the resistance of
the material which is being operated upon.
According to this part of our invention we form the front cover or case N with a
tubular bearing N, Fig. 13, Sheet 7, having a renewable pipe bushing P, to support
the end of the main shaft as described in the first part of this invention; and on
either side of this bearing we form tubes or recesses Q, in which the springs M for
keeping the screw box Lin its position, are placed.
As a modification of this part of our invention, we sometimes bolt or otherwise
secure the screw box firmly to the end of the bearing in the front cover or case N,
and make use of a single spring M as shown in Fig. 14; the spring being adjusted
to the required pressure by means of the bolt R which passes through the adjusting
screw.
A further modification of this arrangement is shown in Fig. 15, in which the
spring M is placed in a recess or chamber formed within the adjusting screw itself.
In either of these modifications, the screw box being secured firmly to the end of
the bearing is available for retaining the pipe bushing P in its place; also the
bolts Z which secure the screw box are convenient for retaining the plate S
(Fig. 14) in its position at the inner end of the bearing, the object of this plate
being to prevent the oil which flows from the bearing, from passing into the grinding
chamber.
In Figs. 1 Sheet 1 and 1
waste oil from the inner end
Sheet 3, an arrangement is shown for conducting the
of the bearing to the dish T. which is placed in a

page_text: position where it will also catch the oil from the outer end of the bearing and from
the pressure block K.
.
We do not confine ourselves to the particular manner of securing the screw box
to the end of the tubular bearing and it may be secured in any convenient manner;
or it may be cast to or formed in one with the tubular bearing. Or as a modifica-
tion the adjusting screw may be formed in one with the pipe bushing P, the latter
being screwed for the whole or a portion of its length and the tubular bearing.
having an internal screw thread to receive the same.
Fig. 154, Sheet 7, shows the application of the single spring arrangement to
those mills which for cheapness, or other reasons, may be constructed without
the bearing for the outer end of the shaft. In this case the screw box is
formed in one with the cover or case N, or it may be secured thereto by bolts or
otherwise.
·Fig. 15³, and 15º, Sheet 8, is a modification, of the single spring arrangement in
which the screw box L' is telescopic and forms a bearing for the outer end of the
shaft. In order to maintain this screw box securely in position, and at the same
time admit of its giving way for the passage of any foreign substance between the
discs we form the screw box with a flange L2, which faces a similar internal
flange N¹ formed in the tubular bearing which is cast to or formed by the cover or
case N; the spiral spring s¹ tending to press the flange L' away from the flange N',
but being held under the necessary adjustable compression by the nut L³ which is
screwed around the screw box L'.
:
Fig. 15, is a similar arrangement of telescopic screw box as applied to those
mills formed without the bearing for the outer end of the shaft.
Figs. 16, 17, and 18 Sheet 9 show a further modification of the adjusting arrange-
ment which is applicable more particularly to that class of mills provided with
rollers instead of discs.
At the end of the sliding frame 1 which carries the roller 2, we form a recess
to receive the head of the screw bolt 3, which according to this arrangement acts
as the adjusting screw and is prevented from turning by the head fitting in the
recess in the sliding frame, or it may be a square neck to the part that passes
through the frame, or any other suitable means, so that the bolt is prevented from
turning, but at the same time free to move endways in the sliding frame. On this
screw bolt we place a spiral spring 4 with one end pressing against the sliding
frame, and the other end against the nut 5, which is adjustable on the screw so as
to give the necessary compression to the spring, the nut being secured by a lock
nut as shown on the drawing, or other suitable means.
In order to move the sliding frame so as to give the necessary adjustment to the
roller we make use of the handwheel 6, the boss of which is tapped to fit the screw
bolt, and the outside of the same is turned or otherwise formed to fit in the bearing 7
on the fixed frame of the machine. In order to secure the handwheel when the
necessary adjustment has been obtained, we make use of a hinged cap 8 and tighten
the same on the boss of the wheel by means of the bolt and wing nut 9, or other
suitable contrivance.
The arrangement shown in the Figs. 16, 17, and 18, Sheet 9, may be applied to
those mills having a roller and a concave, the recess for the head of the screw bolt
being formed in the concave, and the bearing for the boss of the handwheel formed
ou the fixed frame:
.
Fig. 19, shows the arrangement as applied to those mills in which the adjusting
screw is made to revolve, in which case we make use of a hinged nut and tighten
the same on the screw in the same manner as the hinged cap is tightened on the boss
of the handwheel in the before-mentioned arrangement.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is
;.
First.—In a grinding mill with metal discs; constructing the frame in the manner

page_text: shown and described with reference to Figs. 1, 1ª, 1º, and 1º, or the modification
shown in Fig. 1³.
Second. Forming the plate e' and the cover or case N, with accurate machined
or turned faces, in combination with the solid concentric tubular bearing and
renewable pipe bushing as described in reference to Figs. 1 and 1³.
Third. Forming the metal grinding discs, of rings or plates having zigzag ribs
as shown and described, or any mere modification thereof and having one or both
sides of the ribs square, or nearly so, with the face of the disc.
Fourth. The modification having the raised rings on the face of the disc as
described in reference to Fig. 2ª.
Fifth. Forming the metal grinding discs with corresponding sets of ribs formed
in the manner shown on Fig. 2 and 24 on each side of the plate as described in
reference to Fig. 5.
Sixth. Forming the metal grinding discs having the ribs as shown and described
in one with the internal or external cones as described in reference to Figs. 3, 6,
and 7.
Seventh. Forming the metal grinding discs, having the ribs as shown and
described on one or both sides of the plate in combination with separate cones,
formed in the particular manner described in reference to Figs. 3, 6, & 7.
Eighth. In a ribbed disc, forming the outer edge of a series of fine radial grooves,
as described in reference to Figs. 2, 2, and 3.
Ninth. The particular manner of actuating the feeding spout, with the upright
lever engaging the eccentric, as described in reference to Figs. 1, 14, and 1³, and
the arrangement for actuating the same by means of a sliding eccentric as described
in reference to Fig. 12.
Tenth. The modification of the arrangement for actuating the feeding spout as
described in reference to Figs. 8 & 9.
Eleventh. The further modification of the arrangement for actuating the feeding
spout as described in reference to Fig. 10.
Twelfth. The manner of maintaining the screw box for the adjusting screw
in position, having the springs enclosed on either side of the solid concentric
bearing in combination with the renewable pipe bushing as described in reference
to Figs. 1 and 13.
Thirteenth. In a grinding mill having a solid concentric tubular bearing (for
the outer end of the shaft) formed in one with the cover or case N, making
use of a removable screw box having a single spring as described in reference
to Fig. 14.
Fourteenth. The modification of the screw box, having the single spring
inserted in a recess formed in the adjusting screw as described in reference
to Fig. 15.
Fifteenth. The arrangement of a screw box with a single spring, and bolted
firmly to the end of the bearing carried by the case N, in combination with the
plate S forming the oil chamber as described in reference to Figs. 14 and 15.
Sixteenth. Forming or casting the screw box for the single spring arrangement,
in one with the tubular bearing which is carried by the case N. The modification
forming the adjusting screw in one with the pipe bushing P.
Seventeenth. In a grinding mill constructed without the bearing for the outer
end of the shaft; forming the screw box for the single spring arrangement,
either in one with the case N, or secured thereto, as described in reference
to Fig. 154.
Eighteenth. The modification of the spring arrangement wherein the screw box
is telescopic and forms a bearing for the outer end of the shaft as described with
reference to Fig. 15³.
Nineteenth. The modification of the same applied to those mills formed without
the bearing for the outer end of the shaft as described with reference to Fig. 15º.
Twentieth. The manner of adjusting the sliding frame of roller mills as
described in reference to Figs. 16, 17, & 18.

page_text: Twenty-first. The application of the same or a similar arrangement to that
described in reference to Figs. 16, 17, and 18, for adjusting the concave of mills
having a roller and a concave.
Twenty-second. The arrangement of hinged nut or screw box for tightening the
adjusting screw as described in reference to Fig. 19.
Dated this 26th day of September 1891.
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicants.