Improvements in Mills for Crushing and Grinding Berries, Grain, Coal, or other Substances.
Year: 1889

page_text: Date of Application, 15th Apr., 1889
Complete Specification Left, 17th Feb., 1890-Accepted, 22nd Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in Mills for Crushing and Grinding Berries, Grain,
Coal, or other Substances.
I HENRY COURTEEN, of Dean Cottage, Great Ponton, Lincolnshire, Agricultural
Engineer do hereby declare the nature of this invention to be as follows:-
My improvements consist in the employment of revolving grinders or crushers,
working inside other revolving grinders or crushers; both the inside and outside
ones revolve in or on fixed centres, except where in some cases the bearings are
controlled by springs weights or their equivalents, but the inner grinders or crushers
revolve eccentrically with regard to the outer ones. By preference I construct the
Mills in one of the following manners:
(1) I mount on bearings in suitable supports a hollow casing or cylinder, which
I distinguish as the outer grinder, the interior of which is provided with a suitable.
grinding surface whole or in sections. Fixed centrally to this outer grinder at the
exterior one on each side are two hollow round projections revolving in the above
named bearings. Inside the outer grinder and fixed on a spindle which passes
through the above named hollow projections, and which being eccentric to the outer
grinder runs in bearings having a different centre line to the first named bearings is
a grinder or crusher which I call the inner grinder at the periphery of which is a
suitable grinding surface whole or in sections. Both grinders are in work caused to
revolve by suitable pulleys or gearing, and the speed of the one may bear any
required relation to that of the other. The inner grinder may receive motion from
the outer grinder or vice versa by means of a driving pin or pins fixed in the sides of
the latter and passing through a slot or slots in the former, or by gearing connecting
one of the hollow projections or some other part of the outer grinder with the
spindle of the inner grinder, or both grinders may be driven by separate belts or
gearing, or one may take its motion from frictional contact with the other direct
or through material being operated on. In the outer grinder are suitable holes for
allowing the passage out of the mill of the ground or crushed material. These way
be made in the material itself forming the outer grinder, or wire gauze or perforated
sheet metal suitably supported and by preferance mounted in removable frames may
be employed. When wire gauze or perforated sheet metal is fixed at the circular or
annular part the grinding parts are in sectors to clear the gauze or sheet metal, and
the two grinders make an equal number of revolutions, but this disposition is not
necessary where the gauze or perforated sheet metal is only fixed in the sides of the
outer grinder. The berries, grain, coal, lime, slag, quartz, ore, or other material to
be ground or crushed is intro:luced into the mill through the before named hollow
projections or one of them by hand or by any suitable automatic or other arrange-
ment. When required, water or an air blast may be conducted by means of a
suitable pipe or pipes through one of the hollow projections or both to assist in
feeding the material to be operated upon or in its discharge when ground through
the holes or screening in the outer grinder. In work the material intro luced into
the outer grinder fulls to the lower part of it as it revolves, parts being cut away
from the inner grinder when necessary or clearance given in the outer grinder to
insure this, and is then caught between the convex or partly convex grinding parts
of the inner grinder and the concave or partly concave grinding parts of the outer
grinder, and crushed and ground owing to the grinding surfaces in consequence of
their relative eccentricity approaching each other as the mill revolves. By preference,
I make the revolving parts as heavy as convenient to increase the crushing power
by the momentum gained during revolution, and with this in view I also when
required fit a heavy circumferential rim to the outer grinder. When desired the

page_text: grinding parts may be mounted on springs or yielding substances. The bearings in
which the spindle of the inner grinder turns are by preference adjustable to permit
of regulating the distance from each other of the grinding parts of the inner and
outer grinders. These bearings may also when required be kept in position by
springs, or by pistons controlled by compressed air, or by weights, or by a pivoted
lever or levers adjustable or notched for carrying a weight or weights at varying
distances from the fulcrum according to the pressure required, or by a pivoted lever
or levers controlled by an adjustable spring or springs.
(2) In a second form of the mill I employ for the outer grinder a pan somewhat
similar to that of the ordinary. mortar mill having friction rolls underneath and at
sides when required and revolving on a suitable central toe in an adjustable step. A
crosspiece is mounted above the pan on suitable uprights. Fixed in this crosspiece
and descending downwards is a spindle or shaft the lower end of which fits a circular
recess or hole in the centre of the pan. A portion of the shaft between the bottom of
the pan and the crosspiece is eccentric with its bottom end and on this portion revolves
the inner grinder. Motion is given to the two grinders by suitable bevil or other
gearing; they may be connected by a driving pin or pins or they may be connected by
suitable gearing. In the latter case I prefer to use a gear-ring on the pan or outer
grinder in cog with one on the inner grinder. When preferred I make the vertical shaft
to revolve instead of being a fixture, the inner grinder being fixed to the shaft and suit-
able modifications made in the pan and other parts. The material operated upon is
crushed and ground between the grinding parts of the two grinders as in the mill first
described it is fed into the pan or outer grinder by hand or automatically at or near
the part where the two grinders are farthest apart. The crushed and ground material
is discharged through holes or screening in the outer grinder. When the mill is required
for the wet grinding process water may be introduced at any suitable point, but by
preference through the vertical shaft and in such a manner as to lubricate the interior
parts and wash grit away from them, the ground material being carried away by the
water. When preferred 1 employ two or more inner grinders, with corresponding
alterations in the mill, instead of one.
:
(3) A third form of the mill is somewhat similar to the mill first described, but one
side or both of the outer grinder is open in one or more places to receive the material
to be operated upon which fed inwards by hand or automatically. The opening or
openings are partly covered by plating or screening, a suitable place being left
uncovered for feeding, whilst at the lower part an opening or openings may also be
left uncovered to allow exit of the crushed and ground material. By preference I
make the inner grinder in the form of a frustrum of a cone, or of a double frustrum
or of a sheave, the interior of the outer grinder being formed to correspond, and the
grinding surfaces of the latter being parallel or not with those of the former as may
be preferred. In a mill of this form I employ by preference an automatic feed
constructed substantially as follows: an oscillating sloping tray is suspended by
flexible hangers similar to those employed in threshing machines, the hangers being
attached to a suitable frame. At the end of this tray is a hopper provided with an
adjustable door for the passage of material to the tray. Fixed to or in connection
with the tray is a spindle sliding in a bearing fixed in a suitable position. On this
spindle is a collar or projection. A spiral spring is placed on the spindle between the
collar or projection and the fixed bearing. On the outer grinder is a suitable cam
path actuating directly or by means of a lever or other mechanism the spindle
carrying the spiral spring, and, as the mill revolves causing the tray to be pushed
away when desired at the same time compressing the spiral spring. An abrupt step
in the cam path allows the spindle to shoot forward by the recoil of the compressed
spring, the tray moving simultaneously and delivering a supply of material inside the
mill. A modification of this feeder can be used with the other mills.
(4) A fourth form of inill is similar to the third described but one side of the outer
grinder is entirely open, and the central projection on the other side is lengthened, or
a suitable spindle takes its place, and double bearings are by preference provided on

page_text: the same side to carry the lengthened projection or spindle. The spindle of the inner
grinder is also carried by preference in two bearings placed on one side of the mill.
With this form of mill I use when preferred two or more inner grinders instead
of one.
Having now described four mills embodying my improvements I hereby declare
that I do not confine myself to one or other of the forins described, but employ any
suitable modification, or embody in one mill features appertaining to two or more of
those described or features hereinafter described. The outer and inner grinders of
these mills revolve by preference in the same direction, but may revolve in opposite
directions if desired. In the mills revolving vertically the two grinders may be
arranged to elevate the material being operated upon by holding it between opposite
grinding parts, or by means of indentations on their surfaces, so that material too
coarse to pass out of the outer grinder may be operated upon again. The grinding
parts may be smooth, corrugated, or of any form suitable to the work to be done,
and may be bevilled or chamfered off in any required direction. When desired
apply direct motive power to one of the grinders only, the other being set in motion
by frictional contact either direct or through the material being operated upon. The
mill axes may be set at any angle with the ground, instead of horizontal or perpen-
dicular. When the two grinders are connected by gearing, and adjustable or
yielding bearings are used, kept in position by springs, pistons and compressed air,
or by a pivoted lever or levers, I by preference make the bearings of the spindle of
the inner grinder to be moveable in a line of the radius of the centre of the cog
wheel driving it or connecting its motion with that of the outer grinder the supports
or levers carrying them being pivoted on the axis of the said cog wheel or on a
support in line with this axis; or 1 make the bearings of the outer grinder moveable
in a line of the radius of the centre of the cog wheel connecting its motion with that
of the inner grinder. When desired I mount on a suitable part of the mill frame a
crane for the purpose of hoisting or lowering various parts of the mill.
Dated this Thirteenth day of April 1880
COMPLETE SPECIFICATION.
Improvements in Mills for Crushing and Grinding Berries, Grain,
Coal, or other Substances.
I HENRY COURTEEN of Dean Cottage, Great Ponton, Lincolnshire do hereby
declare the nature of the said 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 improvements in the construction and arrangement of mills
for grinding and crushing, wherein crushers or grinders, revolving in similar planes
one within the other, and eccentrically disposed in relation to one another, are
employed, the material under operation being crushed or ground between the periphery
of the inner grinder and the internal peripheral portion of the outer grinder. It also
relates to improvements in the devices employed for feeding the substance to be
operated upon between the crushers or grinders.
According to my invention, I employ by preference two crushers or grinders,
revolving in similar planes one within the other, and mount each centrally upon a
shaft or axis supported in bearings, situato outside, and not forming a part of or
revolving with such crushers or grinders.
The crushers or grinders are caused to revolve eccentrically in relation to one
another, by disposing their shafts or axes upon different centre lines for this purpose,
and in those cases where the outer crusher or grinder consists of a cylinder or casing
with closed ends, I mount it upon hollow trunnions or axes, and pass the shaft or axis
of the inner grinder through one or both of such hollow trunnions, so that the

page_text: onter grinder may revolve freely, notwithstanding it has closed ends, and is traversed
by such shaft.
The material to be operated upon may in some cases be fed into the mill through
such hollow trunnions, which may also admit a water pipe, or be in connection
with a fan, if desired, to assist in feeding and discharging the material under
operation.
In some cases I construct the outer crusher or grinder with one end open, in lieu of
both ends enclosed, and in this case prefer to make the inner grinder in the form of a
frustrum or frustrums of a cone, (splayed out or flanged or not around its edge as
herein after described,) the interior of the outer grinder being of corresponding shape.
The crushers or grinders employed may be arranged to rotate either in a vertical, hori-
zontal, or angular plane, and I prefer that both the inner and outer grinders should be
rotated by positive motive power applied thereto, (as distinguished from one grinder-
being rotated merely by frictional contact with the other, or with the material under
operation). The grinders may be driven at equal or different speeds, and in similar or
reverse directions, (but preferably in a similar direction,) either independently of each
other, or by means of gearing, or driving pins connecting them, as herein after
described.
I prefer that the bearings of one or both grinders should in most cases be connected
with adjustable levers, screws, springs, weights, or their equivalents, in order that the
distance between the acting faces of the crushers or grinders, and consequently the
maximum size of the crushed material, may be regulated or varied, or the grinders
permitted to yield or move apart for the passage between them of any extra hard
foreign body, and in those arrangements hereinafter described wherein adjustable or
yielding bearings are employed and the grinders connected or driven by a counter-
shaft and gearing, I provide means whereby such bearings may be adjusted or shifted,
without disturbing or interfering with the proper engagement of the teeth of the
gear wheels.
;
Various feeding arrangements may be employed in connection with my invention,
such as feed shoots, vibrating or not, creeper or worm feeds, and the like, but I prefer
to employ the arrangement of automatic feed hereinafter described.
I will now proceed to describe my invention more particularly, having reference
to the accompanying drawings, (illustrating various arrangements and modifications
embodying the same,) in which similar letters refer to corresponding parts in all the
figures.
Figures 1, 2 and 3, (Sheet 1,) represent in transverse vertical section, elevation,
and plan, respectively, a crushing or grinding mill, consisting of an outer crusher or
grinder A, enclosed on each side, and provided with hollow trunnions B rotating in
the bearings C, and an inner grinder D, revolving upon a shaft E eccentrically situate
in relation to the grinder A, which shaft E passes through the hollow trunnions Band
rotates in the bearings F situate outside the grinders.
The outer grinder A is here shewn as constructed in the form of two pans or dishes,
each provided with a heavy external annular flange A' at the line of contact, and
secured together by bolts, (not shewn in my drawings,) passing through these flanges.
This heavy flange adds to the momentum and assists the crushing power of the mill,
and I prefer in all cases to make the revolving parts as heavy as practicable for this
purpose.
Positive motive power is shewn as imparted to both the grinders A and D from
the countershaft G, which carries the driving pulley H, and gear wheels I and K,
such gear wheels engaging with other gear wheels L and M, mounted respectively
upon the hollow trunnion B of the outer grinder A, and the shaft E of the inner
grinder D. By varying the relative proportions of the gear wheels, the grinders A
and D may be caused to rotate at various relative speeds. In order to permit the
regulation of the distance between the acting surfaces of the grinders, I have here
shewn the bearings of the shaft E of the inner grinder D, as carried by the levers NN,
which have as their fulcrum the countershaft G. These levers are connected at their

page_text: free extremities, and their position is regulated by the adjusting screw O. If desired
in lieu of adjusting the inner grinder D, the outer grinder A may be made adjustable,
and its hollow trunnions B carried in bearings on the levers N, as will readily be
understood.
In either case it is essential that the fulcrums or pivots of the levers N should be
situate upon the countershaft G, or centre line thereof, since this arrangement will
ensure the countershaft, and the axis or shaft of the adjustable grinder carried by the
levers N, being always maintained at an equal distance apart, and consequently secure
the proper working of the gearing connecting said shafts, when such shaft or axis is
adjusted to a different position. In lieu of the adjusting screw O, springs, sliding
weights, or their equivalents, may be connected with or mounted upon the levers N,
so as to permit the grinders to move apart, and have a certain amount of play or yield,
in case some extra hard foreign body should pass between them; in this case however,
(ie. when springs, weights, or their equivalents are employed,) suitable adjustable
stops or catches, to engage with the ends of the levers, should be provided, in order
that the grinders may be prevented from approaching one another more closely, and
reducing the material to a finer condition, than desired.
The material to be operated upon is fed from the hopper P through one of the hollow
trunnions B, whence it falls to the bottom of the mill, and is crushed or ground between
the periphery of the inner grinder D, and the internal peripheral portion of the outer
grinder A, which constitute the acting surfaces of the grinders, and which, owing to
their relative eccentricity, approach each other during revolution. The crushed or
ground material is then discharged through the annular outlet aperture Q, situate in
the end of the outer grinder, and preferably covered by the screen R, into a suitable
delivery shoot or receptacle, which I have not considered it necessary to illustrate.
S is a pipe, also passing through one of the hollow trunnions B, for admitting water
into the mill when required.
In the modified arrangement illustrated in sectional elevation fig. 4, (Sheet 2,)
positive motive power is shewn as applied to the outer grinder A only, through the
driving pulley H upon the hollow trunnion B thereof; the inner grinder D, is, in
this figure, shewn as rotated merely by frictional contact with the outer grinder A, or
with the material under operation. I prefer, however, to rotate each grinder by
positive motive power applied thereto a more effective action being then obtained.
Although I have not considered it necessary to illustrate the same in every figure
of my drawings, I prefer that in this, and all modifications hereinafter described,
(except that illustrated in fig. 15), the bearings of the shaft or axis of the inner grinder
should be carried by pivotted adjusting lovers, weighted, or connected with springs,
and adjustings screws, or their equivalents; or such bearings may be connected direct
with springs, weights, pistons controlled by compressed air, or their equivalents. It
is obvious, also, that if desired the bearings of the outer, in lieu of the inner grinder,
may be made adjustable, and carried by pivotted levers, or connected with springs,
weights, or equivalent devices.
Fig. 5 Sheet 2, shews in sectional elevation, an arrangement of mill wherein positive
motive power is applied direct to each crusher or grinder, by means of the driving
pulleys H and H', mounted respectively upon the hollow axis or trunnion B of the
grinder A, and the shaft E of the grinder D. In this figure, the bearings of the inner
crusher or grinder D are carried by the rods T, of pistons U, sliding in cylinders V,
filled with compressed air, which forms a cushion for the pistons, and so acts after the
manner of a spring.
In the arrangement shewn in sectional elevation fig. 6, (Sheet 2,) both the inner
and outer grinder rotate at the same speed, positive motive power being imparted from
the outer to the inner grinder, by means of the driving pin W, secured to the outer
grinder A, and passing through a slot X in the inner grinder D. In this and other
arrangements wherein the discharge apertures are formed in the periphery of the outer
grinder, in lieu of in its ends, I provide recesses Y, corresponding with such discharge
apertures, around the periphery or acting surface of the inner grinder, the object of
these recesses Y being to prevent lumps of the material under operation from being

page_text: forced through the gauze or screen R covering the discharge apertures, when the
acting surfaces of the grinders, owing to their relative eccentricity, approach one
another during revolution. When, as in this figure, the outlet apertures extend the
full width of the inner grinder, and the corresponding recesses Y extend in the
direction of the axis of the inner grinder, and are not in the form of uninterrupted
grooves or channels encircling the periphery of the same, the grinders must revolve
at equal speeds. In all cases prefer to protect the gauze or screen R by an inner
screen of stouter material R¹, as shewn, which should however be placed in contact
with the gauze or screen R, in lieu of some little distance therefrom, (as shewn by
error in the drawings,) since, when the two screens R & R' are situate apart, material
too coarse to pass through the screen R, may pass through the screen R³, and collect
between the screens, when it cannot well be removed.
In the sectional elevation figure 7, the outer grinder A is represented as open on
one side, and provided with one trunnion B only, which trunnion is secured to the
extremity of the shaft B¹ carried in the bearings C. Or in lieu of the shaft B', the
trunnion B may be prolonged and carried in the bearings C. The inner grinder D
is in the form of a frustrum of a cone, and the interior of the outer grinder A
corresponds in shape thereto. The material is fed between the grinders at P1, where
their acting faces are farthest apart. In arrangements of this kind, wherein the inner
grinder is of conical form, and the interior of the outer grinder corresponds in shape,
the adjustment or regulation of the distance between the acting faces of the grinders,
may be effected by moving one of the grinders, either in the direction of its axial line,
or in a direction perpendicular thereto, as found most convenient, and 1 shall herein-
after describe and illustrate a simple method of adjusting the crushers or grinders, by
moving them in the direction of their axial line.
Figs. 8 & 9, Sheet 3, represent, in sectional elevation and plan, an improved automatic
feed device, combined with an arrangement of mill consisting of an outer grinder A
enclosed on each side, and mounted on hollow trunnions, and an inner grinder D in
the form of a frustrum of a cone, the interior of the outer grinder being of corre-
sponding shape.
In this arrangement, the material passes into the mill through the aportures Q
in the side of the outer grinder A, which are in the form of curved slots, concentric
with the axis of such grinder. Z is a vibrating tray held suspended by the flexible
hangers a a, and situate beneath a feed hopper P. 6 is a rod or spindle, sliding
in bearings or guides cc, suitably connected at one extremity with the vibrating
tray Z, and carrying at its other ond a friction roller d, which engages with a
cam path e, formed around the circumference of the outer grinder A. f is a
spring surrounding the rod b. The cam path has an abrupt depression e¹ formed
therein, corresponding with one of the inlet apertures Q, or a series of abrupt
depressions e¹ may be employed, corresponding in number with the number of
said inlet apertures. In the drawings, the friction roller of the rod b is shewn as
situate within one of the depressions e'. As the outer grinder A revolves, this
friction roller d will be caused to leave this depression, and, through the rod b,
force the vibrating tray Z away from the mill, compressing at the same time the
spring, by the collar fixed to the rod b. When another depression in the cam
path comes opposite the friction roller d, the rod or spindle will be shot back by
the recoil of the spring f, and the vibrating tray restored to its original position
with a smart jerk, and caused to project its contents through the aperture Qin
the mill. The depressions in the cam path, and the apertures Q, must of course
bo so arranged and timed, as that the vibrating tray will deliver its contents only
when opposite one of these apertures. These apertures Q also serve for permitting
the discharge of the crushed or ground material from the lower part of the mill.
Figs. 10, 11, & 12, Sheet 4, illustrate in sectional elevation, side elevation, and
plan, respectively, an arrangement of mill combined with a slightly modified automatic
feed arrangement.
In this fig., positive motive power is shewn as imparted to both grinders through
the countershaft Gand gear wheels L
KL f. M
Ը

page_text: bearings F of the grinder D are formed in the extremities of the links N¹, which
have their pivots upon the said countershaft, (or centre line thereof) and the position
of these links N' may be adjusted or regulated by the adjusting screws O¹, carried
by the lugs O attached to the framing of the mill. These pivotted links N', take
the place and serve the purpose before referred to, of the pivotted levers N, illus-
trated in figures 2 & 3. The vibrating feed tray Z, is here shewn as mounted upon
the vibrating arm a', pivotted or hinged at all. The upper portion of this arm a¹
is bent over at 6, and carries the friction wheel d, which engages with the cam
path or projection e extending partially around the circumference of the outer
grinder A. f is a spring or equivalent, which exerts its force to maintain the
mouth of the vibrating tray close to the inlet aperture Q. Z' is a guide trough,
in which the discharge end of the vibrating feed tray slides. The action of this
modified feed arrangement is similar to that of the arrangement described with
reference to figs. 9 & 10, Sheet 3, the vibrating tray Z being moved away from the
mill by the action of the cam path e, and returned smartly to its original position
by the contraction of the spring when the termination of the cam path e arrives
at the friction roller d. g is a stationary gate or cover, bearing against, and extending
partly around, the side of the outer grinder A. This gate or cover g is so disposed
and arranged as to cover the apertures Q when they reach the bottom of the mill.
By means of a convenient adjusting screw h, the distance of this gate from the
apertures Q, and consequently the maximum size of the material allowed to pass
out of them, may be regulated. It will be obvious that with slight modifications
the automatic feeding devices above described may be equally well employed in
conjunction with mills wherein one end of the outer grinder is entirely open or
unenclosed, or wherein the feed takes place through a hollow trunnion.
or
In fig. 13, Sheet 5, is illustrated an arrangement of inner grinder D in the form
of a frustrum of a cone, and outer grinder A of corresponding interior shape,
wherein the edge of the inner grinder D is splayed or bevelled outwards, or formed
with an annular flange D'. This flange D' exerts a further grinding action upon
the substance under operation, as it passes out of the mill between such flange
and the lower edge or lip A" of the outer grinder A, and the maximum size of
the crushed material may be regulated to a nicety, by approaching such flange D¹
to, or receding it from, the lip or edge A", which can readily be effected by moving
the inner grinder D in the direction of its axial line, by any suitable arrangement,
such as an adjustable wedge, (as illustrated in fig. 23 Sheet 7,) or an adjusting
screw or lever.
In this figure, also, the well known arrangement of worm
creeper food is illustrated as applied to the hollow trunnion B of the grinder A.
Fig. 14 shews an arrangement similar to fig. 13, except that the worm feed is
dispensed with, and the shaft of the grinder D passes through the hollow trunnion B,
and has its bearings on each side of the outer grinder, in lieu of one side thereof,
as in fig. 13. are adjusting and lock nuts, for permitting the adjustment of
the inner in regard to the outer grinder in the direction of its axial line. By an
error in the drawing, the hollow trunnion B of the grinder A is represented as
carried in one bearing only, which unless of unusual length will not give sufficient
steadiness-it is obvious that the trunnion B should be prolonged, and provided
with a second bearing C, the shaft E of the grinder D being of course prolonged also.
Figs. 15 & 16, represent in sectional elevation and plan, a modified arrangement,
wherein inner and outer crushers or grinders, revolving in a vertical, in lieu of a
horizontal plane, as in the previous arrangements described are employed.
A is the outer grinder, mounted on the vertical shaft or axis B₁, supported at its
lower end in the footstep bearing (". In this arrangement two rotating eccentrically
disposed inner grinders D D are represented, each mounted upon a shaft E which
rotates at its upper portion in fixed bearings, (not shewn in the drawing). Positive
motive power is imparted to all the grinders through the gear wheels L, M, & M",
mounted upon their respective shafts or axes as shewn. R is a cylindrical screen,
through which the ground material has to pass in order to escape through the delivery
apertures Q. kk are guide or guard plates, hinged at 7 to the screen, (or if desired.

page_text: to some convenient part of the framework) and bearing with their free ends upon the
inner grinders D. The object of these guide or guard plates k, is to direct the material
under operation between the inner and outer grinders, so that they may exert their
crushing or grinding action upon it, and also to prevent lumps of material from being
forced through the screen R" by the grinders D, and thus damaging it. This arrange-
ment is adapted for wet grinding.
When the arrangement of gearing illustrated in this figure is employed, it is
necessary that the bearings of the respective grinders should be fixed and not
adjustable.
Figs. 17 & 18 represent in sectional elevation and plan, another modification of
horizontally rotating grinders.
In these figs. a single inner grinder D is employed, mounted on the shaft E,
(situate eccentrically as regards the shaft B',) and equal motion is imparted to both
inner and outer grinders, through the hereinbefore described arrangement of counter-
shaft G and gear wheels I, K, L, & M.
Circumferential outlet apertures QQ, protected by screens R, are provided in this
as in the previously described arrangement fig. 6, recesses Y, corresponding with the
outlet apertures Q, being formed in the inner grinder D for the purpose before
referred to. When the mill is intended to revolve slowly, the bottom of the outer
grinder has by preference a downward slope towards its acting surface, instead of
being horizontal as shown.
Figs. 19, 20, 21, & 22 Sheet 6, represent in sectional elevation various modifications
in the form of the crushers or grinders employed.
In fig. 19, the inner grinder D is provided upon its acting face with longitudinal
angular grooves m m. These grooves mm serve to elevate the material too coarse to
pass through the outlet apertures, and cause it to pass through the crushers or
grinders again. QQ are the outlet apertures, against which a scraper may be caused
to act if required.
In figs. 20 & 21, the inner grinders D are in the form of a series of frustrums from
different parts of a cone, placed centrally together so as to form grinders with a series
of steps therein, the outer grinder corresponding internally in shape.
In fig. 22, circumferential outlet apertures Q protected by screens R being employed,
corresponding annular grooves or recesses Y are formed around the inner grinder D,
for the purpose before described.
Figs. 23 & 24, Sheet 7, represent in sectional elevation and plan, an arrangement
somewhat similar to that illustrated in figs. 13 & 14, Sheet 5, except that the grinders
revolve in a horizontal, in lieu of a vertical, plane. The shaft E of the grinder D is
supported in the footstep bearing F, and moved upon its axial line, towards or from
the grinder A, by the adjustable wedge O. This method of adjustment may equally
well be applied to conical grinders rotating on horizontal axes as illustrated in
figs. 7, 8, 13, 14, 19, 20, 21, & 22.
Figs. 25 & 26, represent in elevation and plan an inner grinder D, one side of
which is provided with channels or grooves m³, which are preferable in cases where
the side or sides of the inner grinder fit closely against the sides of the enclosing
outer grinder, in order to permit the material fed in at the upper part or centre of
the mill to quickly descend along such channels or grooves to the bottom thereof.
In mills wherein the grinders revolve in a vertical plane, the grinders may be
caused to grip between their acting faces, and elevate so as to be operated upon again
material too coarse to pass through the outlet apertures, by so disposing the grinders,
that the point where their acting faces approach most closely, is situate at or near their
horizontal centre line, the grinders being rotated in such a direction as to raise the
material from the bottom of the mill to the said point where they approach most closely.
I prefer that the crushers or grinders should in all cases be constructed with the
well known detacheable or renewable acting surfaces, which acting surfaces may be
provided with teeth or projections if desired.
In conclusion I would observe that I do not claim broadly the employment or use in
combination of crushers or grinders revolving one within the other in similar planes,

page_text: and eccentrically disposed as regards each other, neither do I claim broadly effecting
the adjustment of the acting faces of the crushers or grinders, or allowing them to
yield or move apart by mounting the bearings thereof upon adjustable pivotted levers,
or connecting them with springs or weights, nor do I claim broadly an outer crusher
or grinder with closed ends mounted upon hollow trunnions, which serve for the
admission of the material, and may also admit water or may be in connection with a
fan, as I am well aware that such arrangements were known prior to my invention.
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 mills for crushing and grinding, the employment or use in combination..of
crushers or grinders revolving one within the other in similar planes upon central
shafts or axes situate upon different centre lines and carried in fixed or adjustable
bearings situate outside and not forming a part of or revolving with such crushers or
grinders, substantially as described and illustrated in my drawings.
2. A mill for crushing and grinding comprising crushers or grinders revolving.one
within the other in similar planes upon central shafts or axes situate upon. different
centre lines and carried in fixed or adjustable bearings, wherein each crusher or grinder
is rotated by positive motive power imparted direct thereto, (as distinguished from
rotating one grinder from the other by frictional contact,) substantially as described
and illustrated.
3. In mills for crushing and grinding, the employment or use in combination of
crushers or grinders revolving one within the other in similar planes and eccentrically
disposed in relation to each other, the outer grinder being mounted upon a central
hollow trunnion or trunnions supported in bearings, and the inner grinder upon a
central shaft passing through such trannion or trunnions and supported in bearings
situate outside such crushers or grinders substantially as described and illustrated.
4. In mills for crushing and grinding the employment or use in combination of
crushers or grinders revolving in similar planes one within the other upon central
shafts or axes situate upon different centre lines and carried in fixed or adjustable
bearings, the inner grinder being in the form of a frustrum of a cone provided on its
acting surface with longitudinal grooves, and the interior of the outer grinder of
corresponding conical shape, substantially as and for the purpose described and
illustrated in fig. 19 of my drawings.
5. In milis for crushing and grinding the employment or use in combination of
crushers or grinders revolving in similar planes one within the other upon central
shafts or axes situate upon different centre lines and carried in fixed or adjustable
bearings, the inner grinder being in the form of a series of frustrums of a cone, and
the interior of the outer grinder of corresponding shape, substantially as described and
illustrated in figs. 20 & 21 of my drawings.
6. In mills for crushing and grinding the employment or use in combination of
crushers or grinders revolving in similar planes one within the other, and eccentri-
cally disposed in relation to each other, the outer grinder having outlet apertures
around its circumference, and the acting surface of the inner grinder being provided
with recesses corresponding to such outlet apertures, substantially as and for the
purpose described and illustrated in my drawings.
7. In mills for crushing and grinding, the combination with an inner grinder of
conical form revolving within an outer grinder of corresponding internal shape and
open or unenclosed at one end, of a projecting annular flange 1) formed around the
inner grinder substantially as and for the purpose described and illustrated in my
drawings.
8. In mills for crushing and grinding, the combination with crushers or grinders
revolving one within the other in similar planes upon central shafts or axes supported
in bearings, of pivotted levers carrying the bearings for one of the grinders and
weighted or connected with springs or equivalent devices, and adjusting stops or
B

page_text: catches engaging with the free ends of such levers substantially as and for the purpose
described.
9. In mills for crushing and grinding the combination with crushers or grinders
revolving one within the other in similar planes and mounted upon shafts or axes
supported in bearings, of a countershaft and gearing connecting such crushers or
grinders, and adjustable levers or links carrying the bearings for one of the grinders
and having their fulcrums or pivots situate upon the countershaft or centre line
thereof, substantially as and for the purpose described and illustrated in my drawings.
10. In mills for crushing and grinding comprising crushers or grinders revolving
one within the other in similar planes upon shafts or axes supported in bearings,
connecting the bearings of one of such grinders with pistons working in cylinders
filled with compressed air, substantially as described and illustrated.
11. In mills for crushing and grinding, the combination and arrangement of parts
constituting automatic feed apparatus therefor, and consisting of a vibrating feed tray
carried by suitable supports, moved away from the inlet aperture of the mill by suit-
able connections from a cam path carried by a revolving part of the mill, and returned
to its original position by a spring or equivalent device, substantially as described.
12. In mills for crushing and grinding, the combination and arrangement of parts
constituting automatic feed apparatus, substantially as described and illustrated in
figs. &&9 Sheet 3 and figs. 10, 11 and 12, Sheet 4, of my drawings.
13. The general combination and arrangement of parts constituting machinery or
apparatus for crushing and grinding substantially as described and illustrated in my
drawings.
Dated this 17th day of February 1890.
E. P. ALEXANDER & SON, Fels. Inst. P.A.,
Agents for the Applicant..