A NEW OR IMPROVED GRINDING MILL
Year: 1876

page_text: LETTERS PATENT to Alexander Anderson, Manager of the Northern Agri-
cultural Company, Aberdeen, North Britain, and David Thusk, of the same
Place, Engineer to said Company, for the Invention of "A NEW OR IMPROVED
GRINDING MILL,"
Sealed the 23rd February 1877, and dated the 2nd September 1876.
PROVISIONAL SPECIFICATION left by the said Alexander Anderson and
David Thirsk at the Office of the Commissioners of Patents on the 2nd
September 1876.
ALEXANDER ANDERSON, Manager of the Northern Agricultural Company, Aber-'
deen, North Britain, and DAVID THIRSK, of the same Place, Engineer to said
Company. "A NEW OR IMPROVED GRINDING MILL."
This Invention has reference to a new or improved construction of conical mill
for grinding grain or other substances generally, and to the mode of arranging,
fitting, and securing the cutters or cutting surfaces, or part thereof, in a more simple
and portable manner, for repairing or sharpening and renewing the same, than has
been the case with conical grinding mills heretofore
And the nature and novelty of the Invention consist in making the internal
revolving cylinder with cutters on its outer surface or perimeter of a conical shape
(as for instance, the dimensions are about 36 inches long, 27 inches in diameter at
largest end, and 24 inches in diameter at smallest end) firmly keyed on a strong
horizontal shaft, running in bearing blocks on a suitable bed frame. This conical
cylinder is preferably twelve sided, and has a dovetail slot running from the larger
to the smaller end of each. The slots are slightly tapered for the reception of
portable cutters, one in each of the twelve sides of the cylinder, the external
surface of the cutters forming a circle or cone when the twelve segments are to-
gether, and they are kept in their place by a wrought-iron flange sciewed by bolts
to the largest end of the cylinder, the taper of the dovetail feather and groove other-
wise keeping them firm in their places.
The outer cutting part of the above cylinder works in the hollow internal cutting
part of a half cylinder of a corresponding conical shape (or the same as the external
cutting part of the internal cylinder) formed with a number of segment-shaped
cutters placed, equally divided, in the half outer case or fiame, similar to the staves
[Price 6d1

page_text: of a cask. When all are placed in position and fitting each other, each segment
forms a dovetail to the other, the whole being fixed by a key or cotter driven in at
the extreme side or end of the half circle against a dovetailed snug or joggle, one
or two keys tightening up the whole set of cutters; provision being made for
securing them endways by a ring cast or secured on to the internal part of the
cylinder, at the widest end of the cutters, the wedge shape of the cutters other-
wise keeping them in place all along and at the other end. These external
and internal cutting surfaces of both cylinders are cut with teeth suitable for grind-
ing the particular kind of material that may require to be ground in the mill.
The internal half cylinder is suspended by four regulating screws passing through
the top of the frame or otherwise, and turned by a hand wheel, so that it can be
raised or lowered to suit the quality or fineness of the material to be ground. This
internal half cylinder is preferably fitted endways between two flanges cast or
secured on frame. The material is fed in at an opening at the small end on the top,
preferably by a spout, but for some materials, a hopper and shutter might be
required, as in ordinary use, and the ground material can be delivered at the side or
wide end of the machine. And although the axis of the conical cylinder has been
described as placed horizontally, it is to be understood that it may also be fitted to
work vertically or at an angle as preferred for the particular purpose or material
being ground.
The improvements essentially consist in the mode and means of arranging, fitting,
and fixing the external and internal cutters in their cylinders in the simple and
portable manner described, so that they can be put in and removed, and replaced by
any form of cutters, suitable for the material to be ground, simply and quickly
without interfering with the main working parts of the machine, also in the conical
arrangements for the cutters, above described, in segments of circles; all of which
render the machine, by a small expenditure of time and labour, adaptable for any
grinding purpose, and when the grinding surfaces are worn, admit of their being
replaced in the simplest manner and with the smallest possible loss of time.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Anderson, and David Thirsk, in the Great Seal Patent
Office on the 2nd March 1877.
ALEXANDER ANDERSON, Manager of the Northern Agricultural Company, Aber-
deen, North Britain, and DAVID THIRSK, of the same Place, Engineer to said Com-
pany.
"A NEW OR IMPROVED GRINDING MILL"
Our said Invention has reference to a new or improved construction of conical
mill for grinding grain or other substances generally, and to the mode of arranging,
fitting, and securing the cutters, or cutting surfaces, or parts thereof, in a more simple
and portable manner for repairing or sharpening and renewing the same than has
been the case with conical grinding mills heretofore.
And in order that the nature, novelty, and mode of performing our said Inven-
tion may be properly understood, we shall now proceed to describe the several
Figures on the Sheet of Drawings which we have hereunto appended for the
purpose of showing the best modes and means we are at present aware of for putting
the Invention into effect or practice, the same reference letters indicating the same
or like parts in all the Figures where shown.
Figures 1, 2, and 3 are respectively longitudinal and transverse sections, and a
sectional plan, with the cover removed, of a grinding mill constructed in accordance
with and illustrative of one modification of our said Invention or improvements,
suitable for grinding broken bones into a coarse granular state for making manure,
or maize, or beans, pease, or oil cake into a similar condition for the food of animals,
or other such substances into a granular state.
•
Figure 4 is an inside view of the hollow semicircular cover or case E, showing

page_text: the internal angled or scroll ribs E¹ for conducting the partially ground material
from a back part of the cutting case F to the front of the entering side of this case
E, which is secured over the internal revolving grinding barrel A, A¹, S, by the
screw bolts E¹¹ to the top of the main frame C.
Figures 5 and 6 are respectively an end and an outside face view of one of the
minding segments S, shown detached to a large scale of the revolving conical bariel
A, A', S, which has the whole of its outer cutting or grinding surface formed or
built of these segments S, as seen in Figures 1 and 2.
Figures 7 and 8 are respectively an end and an inside view, showing the cutting
face of one of the segments T, which form the internal cutting surface of the
stationary semicircular case F, and shown also to a large scale detached therefrom,
to show its construction and the form of the teeth t
Figures 9 and 10 are corresponding end and inside face views of a narrow wedge
or cutting segment T¹, preferably driven in along the feeding-in edge f of the case
E after all the segments are placed in it, so as to secure them. This wedge T¹ is
secured by a screw f" at the large end after being driven in, and it has its cutting
teeth t¹ formed at a much greater angle than in the other segments S, T, to assist
in feeding in the material to be ground at the entering side f, and every alternato
tooth 8 of the segments S is cut away at the feeding-in end s¹ below the hopper E³
for this purpose. All these cutting segments S, T, and T¹, Figures 5 to 10, forming
the grinding surfaces of the revolving conical barrel A, A¹, S, and hollow case F,
are or may be formed of chilled cast iron, or hardened or tempered steel, or of
other know mixtures of these with tin or other metal. The cutting surface or
teeth are formed on these segments S, T, T¹, by sharp angled or spiral ridges 8 and t
along or across them, formed with angled grooves between, leaving the ridges nearly
radial or vertical and sharp along the outer cutting edge, like saw or ratchet teeth
in cross section, as seen in Figures 1 to 10.
Referring to Figures 1, 2, and 3, the body of the internal revolving barrel or
cylinder A, A, is formed of cast iron, with a strong turned conical outer circum-
ferential web A, and strong ends and eyes A', by which it is keyed to its carrying
and driving shaft B, revolving in bush bearings C¹ in the main open hollow or cast-
iron box frame C, secured by the screw bolts C to the stone or other suitable
foundation D The grinding barrel A, A¹, works within the opening C" of the frame
C, and the fast and loose driving pulleys B' of the shaft B, within the other
opening C and a fly wheel B¹¹ on the extreme outer end of the shaft and frame
B, C.
The essential improvement or novelty of the Invention consists in making or
building the outer cutting or grinding surface of the conical barrel or cylinder
A, A', of long tapered or conical stave-like segments S (shown in Figures 5 and 6)
as say twelve in circumference for such a grinding mill as that shown in the
Drawings, with a barrel A, A³, about thirty-six inches long, twenty-four inches in
diameter at the small feeding-in end, and twenty-seven inches in diameter at the
large discharge end, and which is found to answer well for the purposes described;
but a greater or less number of segments may be used. These new or improved
segments S are each secured by a dovetail feather S¹¹ on their back or inner side,
tightly fitted and inserted into a corresponding dovetail groovo S¹, planed or cut
longitudinally in the centre of each twelfth division of the circumference or body A
of the conical barrel A, A1, the groove and feather S¹, S", being slightly tapered in
the width, widest at the large end from which the segments S are driven in, with
their backs bearing on the body A until all their edges bear on each other and their
ends coincide with the large end A¹, or a recess there for bolting on the wrought
iron ring A which secures all the segments S in position and prevents them from
slackening back; the tight fitting of the tapered or angled edges of the dovetail
feathers and grooves otherwise keeping all the segments firmly in position. When
the segments S are put together on the barrel A, A², they cover the whole of its
outer circumference with their cutting teeth or surface. This conical cutting or
grinding barrel A, A¹, S, so fitted, works in the semicircular hollow internal cutting

page_text: part T of the stationary or non-revolving corresponding hollow semi-conical cylinder
or case F, that is, corresponding to or nearly fitting the external cutting part S of the
internal cylinder A, A, T, and formed by a number of longitudinal segmental plates T
with their angled or scroll cutting teeth t, in this case formed on the inner surface
(as seen particularly in Figures 7 and 8) and placed equi-distant within the portable
semicircular or conical case F, carried in the lower part of the space C¹¹ of the frame
C, somewhat similar to the staves of a cask. When all these segments T are thus
placed in position in this case F, edge to edge, each segment forms a securing
dovetail to the other at T, while the whole are bound or fixed by the wedge
shaped segments T¹, Figures 9 and 10, but it might be by one or more keys or
.cotters driven in at the extreme sides or edges of the half circle of segments T,
where there are fixing dovetail flanges or snugs f. f, projecting inwards, against
one of which at the feeding-in side below the hopper E the wedge or key T¹ acts
to tighten up the whole set of segmental cutters T, provision being made for
securing them endways by an internal projecting rim F, cast or secured on to the ]
inner wide end of the semicircular case F, in which the cutting segments when thus
secured form an internal conical cutting surface all round it; the wedge shape of
the cutters otherwise keeping them in place all along their edges T, and at the
other end.
•
The external and internal cutting surfaces S, T, of the internal revolving conical
cylinder A, A¹, S, and external stationary semicircular case F, T, are cut with
teeth t, as herein-before described, or otherwise varied as to pitch or shape suitable for
grinding the particular kind of material that may require to be ground in the inill.
The internal half conical or cylindrical case F, T, is suspended within the recess
C" of the main frame O by four or more strong screw links G passed up through 2
the frame C from the ends of the strong springs H, carrying the case F by bearing
blocks F working down through guides C³ in the ends C of the recess C₁ in the
frame C; the raising or lowering of the screw links and grinding case F, T, being
effected by the regulating screw nuts g, or it might be screw wheels above the frame
C, and by the four (or more) pinching screws and jamb nuts at h in the cover E
acting in the reverse direction to the springs H, thus regulating the distance
between the cutting surface of the internal grinding barrel A, A¹, S, and the cutting
surface of the case F, T, to suit the quality or fineness of the material to be ground;
but the links G might be attached to bearers or levers attached to or acting on the
movable case F, T, instead of the springs for giving the like regulating action.
This lower or outer halt conical or cylindrical case F with its internal cutting
segments T is preferably fitted endways between the two flanges C cast or secured
on the inner end C' of the main frame C The. material is fed in through an opening
and hopper E on the cover or top case E, or it might be by a spout or hopper with
shutter, according to the requirements of the material being ground, and such as are
in ordinary use for other constructions of grinding mills. The ground material
after being so fed in at the narrow end and space E, and ground by passing through
between the grinding surface S of the revolving cone, and that T, T¹, of the lower
case F is by the angular form of the teeth gradually screwed to and delivered at
the wide end FS of the case F by a lateral or end spout J, J', into elevators or bags,
or other receptacles as required. And although the axis B of the revolving conical
cylinder A, A¹, S, has been described and shown as placed horizontally, it is to be
understood that it may also be fitted to work at an angle, or even vertically when
preferred, to suit any particular place, purpose, or material to be ground.
The improvements essentially consist in the mode of arranging, constructing, and
fitting or fixing the external and internal cutters or segments S and T, T', in the
revolving cone A, A, and in the stationary case F in the simple and portable
manner described, so that they can be put in and removed and replaced by others
in a very short time with any desird form or fineness of teeth 8,'t, or cutting surface
suitable for the material to be ground without interfering with the main working
parts of the machine.
Although the surface or body of the conical barrel A, A', has been shown solid, it

page_text: is to be understood that it may be made in rings or discs keyed on the shaft B;
and, although it has been shown as round, it will be obvious that it may be made
polygonal where the segments S bear on it, and these made flat on their back to
suit the flat faces of the barrel. The grinding segments S, T, may when desired be
also secured to the cylinder A, A¹, and case F, by bolts with countersunk heads or
nuts, instead of or in addition to the dovetail grooves, or feathers, or edges S¹, S¹, T¹,
without sacrificing their portability or ease of attachment and removal
Having now described the nature of our said Invention and the manner of
performing the same, we have to state that we do no restrict ourselves to the
precise details herein described or delineated, but what we consider novel and
original and therefore claim as the Invention secured to us by the herein-before in
part recited Letters Patent is,—
First. The general arrangement or construction of. a conical grinding mill,
substantially as herein described in reference to and shown in the accompanying
Drawings, or any mere modification thereof
Second The constructing and fitting of the cutters or grinding surfaces of conical
grinding mills in portable segments of hard cast steel, iron, or other metal, substan-
tially in the manner and for the purposes and advantages herein described and
shown in the accompanying Drawings, or any mere modification thereof.
Third. The fitting and securing of the cutting segments S to the revolving barrel
A, A¹, by dovetail slots and feathers S¹, S, substantially in the portable manner
and for the purposes herein described and shown in the accompanying Drawings, or
any mere modification thereof.
In witness whereof, we, the said Alexander Anderson and David Thirsk, have
hereunto set our hands and seals, this Twenty-seventh day of February,
in the year of our Lord One thousand eight hundred and seventy-seven.
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
ALEX. ANDERSON (L.S.)
DAVID THIRSK.
(L.B.)