Year: 1887

page_text: Date of Application, 30th June, 1887
Complete Left, 27th Mar., 1888
Complete Accepted, 4th May, 1888
I, JAMES THOMAS STAPELTON, of York House, Spring-Head Road, Northfleet, in
the County of Kent, French Millstone Manufacturer do hereby declare the nature of
this invention to be as follows
The object of my invention is to construct bed millstones for grinding cements and
other hard substances in such a manner that they may be more durable than those
now in use.
I construct the inner portion of the millstone of a mixture of cement and pieces
of burrstone roughly cubical and about one inch in length. This inner portion is
star-shaped and has ten projecting edges on its outer circumference equally distant,
with the sides sloping away equally inwards from the projections and meeting at an
obtuse angle. The outer portion of the millstone is formed of ten skirt burrs fitting
into the ten recesses of the inner portion. The surface of each skirt burr slopes for
a short distance down to the edge of the next skirt burr reckoning in order of
revolution, so that the front edge of each skirt burr forms the back edge of a
master furrow. The joint between two skirt burrs is in a tangential line with the
projection on the inner portion of the millstone, and the circumference of a circle
drawn round the centre of the millstone at a distance of about three and one-half inches
from that centre.
I use ten projections and ten skirt burrs and recesses in preference, but I do not
limit myself to that number.
DOLL 3
AT
1007

page_text: Improvements in Bed Mill Stones for Grinding Cements, Coprolites,
and other Hard Substances.
· I, James ThomaS STAPELTON of York House, Spring Head Road, North Fleet in
the County of Kent, French Millstone Manufacturer 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:-
The object of my Invention is to construct bed millstones for grinding cements
and other hard substances in such a manner that they may be more durable and
require less labour and attention while they are in use.
I construct the inner portion of the Bed Millstone of a mixture of cement and
pieces of burrstone roughly cubical or oblong and of any suitable length. This
inner portion is star shaped and has ten projecting points on its outer circumference,
equally distant with the sides sloping away equally inwards from the projections and
meeting at an obtuse angle.
The outer portion of the Millstone is formed of ten skirt burrs made of the stone
commonly known as "French Millstone" fitting into the ten angles of the inner
portion.
The joint of each two burrs forms the back or deep edge of each Master furrow.
The joint between the skirt burrs is in a line which is tangential to the circumference
of a circle drawn round the centre of the Millstone at a distance of about three and
one half inches from that centre, and passes through the point on the star shaped
inner portion.
I use ten projections and ten skirt burrs and ten Master furrows in preference,
but I do not limit myself to that number.
And in order that my invention may be more fully understood and carried into
practice I will now proceed to describe the same with reference to the accompanying
drawing which shews a plan of the Invention.
The innor star shaped portion F of the Bed Millstone is constructed of a mixture
of cement and pieces of Burrstone or of any other easily wearable substance or
composition. The outer portion of the Bed Millstone A A. . . . is constructed of
ten or any other number of skirt burrs fitted into the ten anglos B B . . . . of the
inner portion.
The joint of each two burrs forms the back or deep edge of each Master
Furrow CC....
When the cement or other substance to be treated is being ground it issues through
the eye of the Runner Stone and falls upon the inner portion F of the Bed Millstone
from thence it is carried on to the skirt burrs A. A... by the centrifugal force
developed by the runner and is ground and falls off at the ends of the furrows.
When the grinding surfaces aro working the greatest grinding power will be
impressed on those parts of the stones which are at the greatest distance from the

page_text: centre hence, the Bed Millstone will have a tendency to wear unevenly and cause
the Bed Millstone face to slope from the centre towards the circumference but in my
invention this difficulty is overcome as the central portion is so selected as to he
more easily ground away than the outer portion hence the Bed Millstone will wear
down perfectly flat if the correct ingredients are used for the manufacture of the said
inner portion.
The star shaped central portion may be made of any required thickness and
hence the Bed Millstone made by my invention will last much longer than the
ordinary stono.
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
The construction of a Bed Millstone in which the centre portion is made of some
easily wearable substance or composition to obviate the disadvantages caused by the
centrifugal force developed substantially as hereinbefore set forth and illustrated in
the accompanying drawing.
Dated this
day of
1888.
CASTLE SMITH,
"Invention Office,'
54, Fleet Street, London, E.C.,
Agent for the Applicant.
CASTLE SMITH,
"Invention Office,"
54, Fleet Street, London, E.C.,
Agent for the Applicant.