IMPROVE- MENTS IN OR APPLICABLE TO THE CONSTRUCTION OF MILLS FOR GRINDING FLINT, STONE, BONE, GLAZE, AND OTHER LIKE SUBSTANCES
Year: 1884

page_text: I, WILLIAM BOULTON, of Providence Foundry, Burslem, in the County of
Stafford, Engineer, do hereby declare the nature of my Invention for "IMPROVE-
MENTS IN OR APPLICABLE TO THE CONSTRUCTION OF MILLS FOR GRINDING FLINT,
STONE, BONE, GLAZE, AND OTHER LIKE SUBSTANCES" to be as follows:-
This Invention relates to certain improvements in or applicable to the con-
struction of mills for grinding flint, stone, bone, glaze, and other like substances;
special objects of the improvements being to reduce the pressure of the heavy
grinding stones or runners upon the paved bottom of the pan, and to cause part of
such pressure to be transferred to and borne by the footstep of the upright
revolving shaft, and to reduce the power required in new or existing pans to
properly grind such materials.
Existing arrangements of such grinding mills comprise a large pan generally
made of wood or iron of any required diameter and the bottom of which is paved
with hard stones. Centrally within this pan there is placed an upright shaft
which is revolved by suitable gearing, and is provided with laterally extending
and depending arms by means of which large grinding stones or runners (some
weighing from about 20 to 30 cwt. each) are propelled over the paved bottom of
the pan. The material to be ground is introduced into the pan with a proper
proportion of water, and as the heavy stones are revolved or propelled over the
paved bottom of the pan, the material is pulverized between them.
Such arrangements are very disadvantageous in that the paved bottom of the
pan has to bear all the pressure exerted by the said runners or heavy stones, and
this is very destructive to the wear of the bottom of the pan, and of the stones,
and of the gearing, and moreover the power required to effect the operation of the
machine is excessive.
As hereinbefore referred to, it is a special object of the present improvements
to remedy these defects in the manner referred to, vizt, by reducing the great
pressure of the grinding stones upon the paved bottom of the pan by causing
part of it to be transferred to and borne by the footstep of the upright revolving
shaft.

page_text: In adapting the improvements to existing arrangements of grinding mills I
attach to or provide the revolving arms thereof (and which may be either the
existing or usual arms or new arms) with cross bars, brackets, or other equivalent
appliances which may be screwed or otherwise secured to such arms, and which
are also connected to the slug iron for the purpose of supporting one or more spiral
or other springs or their equivalent, and when constructing a new mill I make the
arms of a corresponding or equivalent formation to afford like or equivalent
provision for carrying or supporting the said spring or springs. The large
grinding stones or runners are connected to these springs by suspending them by
grappling irons or like means such as screwed pins secured in holes drilled in the
stones, and the screwed pins whether directly connected to the stones or to the
grappling irons pass up through the said springs, and facility is afforded by
the provision of nuts or like means above the said cross bars for regulating the
pressure of the stones or runners on the paved bottom of the pan, so that more or
Jess of the weight of the said stones may be transmitted to and borne by the
footstep of the upright shaft. The provision of this facility is of great advantage,
as when the pan is charged with rough material a greater degree of crushing power
is required for a time, and as the larger pieces pass between and under the grinding
stones or runners the latter are caused to rise and release the springs giving more
crushing power, and as the material gets more finely ground it does not require so
much weight, and the runners fall and the springs take part of the weight, which
can thus be regulated with great facility by means of the above referred to
improved arrangement, and also by means of raising and lowering the footstep.
If-it-is-wished to drive_the_mill faster, the bottom may be paved concave to more
evenly spread the material to be ground, or, if the centrifugal force is-too-great,
stops may be fixed against the outer casing to guide the material moro to the
centre. And to further facilitate the free action of the stones or runners in rising
'or falling I suspend a kind of cradle or frame carrying rollers so as to lessen the
friction between the stones and the said depending or hanging arms which propel
the runners within the pan.
Dated this 17th day of April 1884
DAY, DAVIES & HUNT,
321, High Holborn, W.C.,
Agents for the Applicant.

page_text: I, WILLIAM BOULTON, of Providence Foundry, Burslem, in the County of
Stafford, Engineer, do hereby declare the naturo of my Invention for "IMPROVE-
MENTS IN OR APPLICABLE TO THE CONSTRUCTION OF MILLS FOR GRINDING
FLINT, STONE, BONE, GLAZE, AND OTHER LIKE SUBSTANCES," 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 cortain improvements in or applicable to the con-
struction of mills for grinding flint, stone, bone, glaze, and other like substances;
special objects of the improvements being to reduce the pressure of the heavy
grinding stones or runners upon the paved bottom of the pan, and to cause part of
such pressure to be transferred to and borne by the footstep of the upright revolving
shaft, and to reduce the power required in new or existing pans to properly grind
such materials.
Existing arrangements of such grinding mills comprise a large pan, 1, similar or
substantially similar to that illustrated on the annexed drawings, and which is
generally made of wood or iron of any required diameter, and the bottom of which
is paved with hard stones, 2. Centrally within this pan there is placed an upright
shaft, 3, which is supported by a footstep, 4, and is revolved by suitable gearing, 5,
and is provided with laterally extending and depending arms, 6, 7, by means of
which large grinding stones or runners, 8, (some weighing from about 20 to 30 cwt.
each) are propelled over the paved bottom, 2, of the pan. The material to be
ground is introduced into the pan, 1, with a proper proportion of water, and as the
heavy stones, 8, are revolved or propelled over the paved bottom, 2, of the pan, the
material is pulverized between the stones, 8, and the said paved bottom, 2.
Such arrangements are very disadvantageous in that the said paved bottom of
the pan has to bear all the weight of and pressure exerted by the said runners or
heavy stones, 8, and this is very destructive to the wear of the said bottom of the
pan, and of the stones, and of the gearing, and moreover the power required to effect
the operation of the machine is excessive.
As hereinbefore referred to, it is a special object of the present improvements to
remedy these defects in the manner referred to, vizt. by reducing the great pressuro
of the grinding stones, 8, upon the paved bottom, 2, of the pan, by yieldingly
suspending them and causing part of such pressure to be transferred to and borne
by the footstep, 4, of the upright revolving shaft, 3.
On the accompanying drawings, Fig; 1 represents in plan view, and Figs, 2,
and, 3, in sectional elevation, the application of the present improvements to such
an arrangement of grinding mills as is hereinbefore referred to, but I wish it to be
understood that such improvements are also in like manner applicable to other
arrangements of such grinding mills.
The section in Fig, 2, is taken through about the line a-b, Fig; 1, the right
hand half looking in the direction of the arrow, c, and the left hand half looking in
the direction of the arrow, d.
As aforesaid, 6, represents the usual revolving arms; 7, the usual depending arms
for propelling the stones, 8, and 9, is the usual slug iron.
In adapting the present improvements to such an arrangement, I attach to the
said revolving arms, 6, (and which may be either the existing or usual arms, or new

page_text: arms,) or to the boss, 10, thereof, radial or outwardly extending cross bars, brackets,
or other equivalent supporting means, 11, which may be screwed or otherwise
secured to such arms, 6, or to such boss, 10, and which are or may be also connected
to the slug iron, 9.
In the arrangement illustrated in Figs; 1, to, 3, the supporting brackets 11, are
shown as connected to the slug iron, 9; but in the sectional arrangement illustrated
in Fig; 4, a supporting bracket, 11, is simply screwed (or it may be otherwise
secured) to the existing arm, 6, and provided with a vertically adjustable bar or
extension, 11*, overhanging the stone, 8, it is intended to carry, and without being
connected to the slug iron.
Such brackets, 11, 11%, or such other equivalent means as may be used, thus
afford means of supporting one or more spiral or other springs, 12, or other
equivalent yielding contrivances, and to these springs or equivalent supporting and
yielding contrivances the large grinding stones or runners, 8, are connected by
being suspended therefrom by grappling irons, 13, or like means such as pins, 14,
secured in holes drilled in the stones 8, and by other suitable connections, 15, which
pass up through the said springs 12, and socket piece, 21; and facility is or may
be further afforded by slots, 16, in the supporting brackets 11, 11x, for shifting or
adjusting the position of the stones; and by the provision of nuts, 17, or like
means above the said cross bars or brackets, and socket piece for regulating the
pressure of the stones or runners on the paved bottom of the pan, so that more or
less of the weight of the said stones may be transmitted to and borne by the
-footstep, 4, of the upright shaft, 3. The provision of this latter facility is of great
advantage, as when the pan-is-charged with rough material a greater degree of
crushing power of the grinding stones or runners is required for a-time, and as tho
larger pieces pass between and under the said stones or runners the latter aro
caused to rise, and being then less supported by the springs they give more
crushing power, and further as the material gets more finely ground up it does not
require so much weight, and this is obtained as desired by the then more extended
springs, 12, taking part of the weight off the runners, the crushing force of which
can by these means be regulated with great facility, and also by means of raising
and lowering the footstep.
To further facilitate the free action of the stones or runners, 8, in rising or
falling, I suspend by chains or other suitable means, 18, a kind of cradle or
frame, 19, carrying rollers, 20, so as to lessen the friction between the stones and
the said depending or hanging arms, 7, which propel the runners within the pan.
If it is wished to drive the mill at a specially fast rate, the bottom may be
concavely paved to more evenly spread the material to be ground; or, if the
centrifugal force is too great, stops may be fixed against the outer casing, 1, to
guide the material more to the centre.
In constructing a new mill, the revolving arms may be otherwise made of an
equivalent formation to that hereinbefore described, the present improvements
having more particular reference to the application of suitable means similar or
substantially similar in their action or effect to those herein before described, than
to any particular means to be employed in attaining such object, which may
obviously be effected by other means equivalent to those hereinbefore described.
Having now particularly described the nature of my said Invention and in
what manner the same is to be performed, I declare that what I claim is
1. The herein before described improvements in or applicable to the construction
of mills for grinding flint, stone, bone, glaze, and other like substances, such
improvements consisting in yieldingly suspending the heavy grinding stones or
runners from extensions or connections of the upright revolving shaft, for the
purposes of reducing their pressure upon the paved bottom of the pan, and trans-
ferring part of such pressure to the said upright shaft and causing it to be borne
by the footstep thereof, substantially as described.

page_text: 2. The application to such mills for the purposes stated of the hereinbefore
described brackets 11, 11*, or other equivalent means of support, springs 12, or
other equivalent yielding means of suspension, and grappling devices, 13, or other
equivalent means of connection to the stones.
3. The further combination therewith, of the chains or equivalent means of
suspension, 18, cradle or other form of bearing frame, 19, and friction rollers, 20,
between the depending propelling arms, 7, and runners, 8, for lessening the friction
between such parts.
Dated thie 3rd day of December 1884
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C.,
Agents for the Applicant.