IMPROVEMENTS IN MACHINERY FOR POLISHING, GRINDING, AND EDGING SLABS, OF MARBLE, SLATE, AND OTHER MINERALS
Year: 1867

page_text: the County of Middlesex, for the Invention of "IMPROVEMENTS IN
MACHINERY FOR POLISHING, GRINDING, AND EDGING SLABS, OF MARBLE, SLATE,
AND OTHER MINERALS."-A communication from abroad by Stinson
Hagaman, of Weisport, Carbon County, State of Pennsylvania, United
States of America.
Sealed the 8th February 1868, and dated the 11th September 1867.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents, with his Petition, on the
11th September 1867.
1, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE
MENTS IN MACHINERY FOR POLISHING, GRINDING, AND EDGING SLABS OF MARBLE,
SLATE, AND OTHER MINERALS," to be as follows:-
The machine for grinding and polishing slabs of marble, slate, and other
minerals consists of a frame of any suitable material in the horizontal bars
whereof are mounted the bearings of a vertical shaft; on this shaft is mounted
a wheel of suitable dimensions of pumicestone or other suitable grinding
material, or coated with the same or with emery powder, as may be desired;
said shaft is also provided with a driving pulley, by means of which motion is
[Price Sd.1

page_text: imparted to the apparatus from any source of power. On the frame are
arranged bearings for any desirable number of small vertical shafts arranged
at equal distances from the driving shaft. These shafts can slide up and
down in their bearings, and on top of each is mounted a disc, within the
surface whereof a rectangular or other incline is arranged, in which the slab
to be ground or polished is placed and held by a set screw. The lower end of
each shaft rests on the small arm of a lever or treadle, whereby the shaft can
be raised or lowered at will. By placing a slab on one of the discs and raising
its shaft by the lever the upper surface of the slab can be brought against the
under surface of the grinding wheel, and by revolving the latter the face of the
slab will be ground as desired. An adjustable sleeve on the disc shaft secured
by a set screw acts as a stop and gauges the height of the shaft. These disc
shafts may be stationary or revolved by the aid of toothed wheels taking into
a pinion mounted on the driving shaft, where they all revolve in a direction
opposite to that of the disc shaft and polishing wheel. A set of discs for
holding slate may also be arranged above the polishing wheel so as to be
brought against the upper surface thereof.
I will now proceed to describe a modification of the above machine which
I have found convenient to use for grinding and polishing school slates, and it
will be readily understood that the same or any part thereof may also be
applied to grinding and polishing slabs of marble and other mineral, though
I have found the machinery just described the most convenient for that purpose.
The parts of the polishing machine are disposed in a frame provided with a
vertical shaft mounted in suitable bearings, and receiving a slow motion through
appropriate gearing from any source of power; an upper and a lower disc are
set upon the shaft as an axis, which revolve with it. A number of vertical
shafts also pass through the discs sliding loosely therein, and rest at their
lower extremities on springs, which have one end secured to the under side of
the lower disc, and are provided at their free ends with friction rollers, which
run upon a track; this track can be raised or lowered at will to regulate the
pressure of the springs upon the lower ends of the small spindles, thereby
regulating the pressure of the slates against the rubbing bed. On the upper
end of each vertical shaft is mounted a disc, in which a mortise of size and
shape required is arranged to hold the slates to be ground; or the same object
may be obtained by adjustable clamps disposed on, said discs; these mortises
or moulds are to be removable for the purpose of fixing and changing the
slates. Each vertical shaft also carries a pinion, which takes into a stationary
toothed segment provided with internal gearing. By this means as the centra
shaft is revolved the vertical shafts are carried round the central shaft as a

page_text: axis, and at the same time revolve each round its own axis. Upright shafts,
two, three, or more in number, are arranged in the framing at equal distances
from the central shaft, and outside the discs above mentioned, on the upper
ends of which shafts are mounted grinding wheels of different but graduated
grade of grit. Motion is given to the shafts by means of belts or by any
other suitable method, so that they have a greater velocity than the central
shaft, and the slates are pressed by the springs against the surfaces of the
grinding wheels. Sleeves are fitted to slide on the vertical shafts beneath the
discs, which may be secured as desired by the aid of set screws; nuts are also
arranged around these shafts directly below the sleeves. so that when the set
screw is loosened the sleeve can be accurately adjusted by means of the nuts,"
thereby regulating the pressure of the springs upon the slates lying in the
discs and pressing them against the grinding surfaces of the wheels. The
grinding wheels may also be made adjustable on their shafts. by the like or
any appropriate device. The slates are only intended to revolve around the
shaft as an axis while subjected to the grinding operation, and for this
purpose the terminal points of the interna! gearing of the segment or ring are
vertically beneath the points of the peripheries of the grinding wheels which
the discs first strike, and finally quit the said grinding wheels. For the
purpose of bevilling or edging the slates they are introduced between guides
and slid along the bottom piece until they reach emery wheels mounted on
vertical shafts. The emery wheels receive their motion from a driving wheel
or from any suitable source of power, and have their edges beveled; they are
also adjustable to enable the edges of the slates to be ground to the thickness
required.
Although the shafts just above are described as vertical, and the wheels as
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Melville Clark in the Great Seal Patent Office
on the 9th March 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of September, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year.

page_text: of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Alexander Melville Clark, Her special licence, that I, the said
Alexander Melville Clark, my, executors, administrators, and assigns, or such
others as, I, the said Alexander Melville Clark, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MACHINERY FOR POLISHING, GRINDING, AND EDGING SLABS OF
MARBLE, SLATE, AND OTHER MINERALS," a communication to me from abroad
by Stinson Hagaman, of Weisport, Carbon County, State of Pennsylvania,
United States of America, upon the condition (amongst others) that I, the
said Alexander Melville Clark, my, executors or administrators, by an instru-
ment in writing. under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and immediately.
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, 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, reference being had to the Sheet of Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to say)
This Invention relates to a machine for polishing, grinding, and edging slabs
of marble, slate, and other minerals.
In the accompanying Drawings, Figure 1 is a side elevation, and Figure 2
a detail horizontal section of this Invention, as applied to the polishing of
slabs of marble, slate, and other minerals: Figure 3 is a plan or top view of
this Invention as applied to the polishing of school slates, and Figure 4 is a
side elevation thereof; Figure 5 is a horizontal section thereof at line 2, x, of
Figure 2 Figure 6 is a side elevation of the edging apparatus; and Figure 7
is a sectional view of the bevel or edging wheels. Similar letters on Figures
1 and 2 of the Drawings relate to similar parts.
A is a frame of any suitable material, in the horizontal bars whereof are
bearings for the vertical shaft B. On shaft B is mounted a wheel C of suitable
dimensions of pumicestone or other suitable grinding material, or coated with
the same or with emery powder as may be desired. Motion is imparted to
the driving pulley D from any source of power. On frame A are arranged
bearings for any desirable number of small vertical shafts E, arranged at equal

page_text: distances from shaft B. The shafts E can slide up and down in their bearings,
and on top of them is mounted a disc F. within the surface whereof a
rectangular or other incline is arranged. in which the slab to be ground or
polished is placed and held by a set screw a, as seen in Figure 2. The lower
end of each shaft rests on the small arm of a lever or treadle G, whereby the
shaft can be raised or lowered at will. By placing a slab on one of the discs F
and raising shaft E by lever G' the upper surface of the slab can be brought
against the under surface of the grinding wheel C. and by revolving the latter
the face of the slab will be ground as desired. An adjustable sleeve bon
shaft E secured by a set screw e acts as a stop, and gauges the height of the
shaft E. The shafts E may be stationary or revolve by means of the toothed
wheels d. d. meshing into pinion e mounted on shaft B, where they ali revolve
in a direction opposite to that of the shaft E and polishing wheel C. A set
of discs for holding slate may also be arranged above the wheel C. so as to be
brought against the upper surface thereof.
will now proceed to describe the modification of the above machine
which I have found convenient to use for grinding and polishing school slates,
and it will be readily understood that the same or any part thereof may also
be applied to grinding and polishing slabs of marble and other mineral, though
I have found the machinery just described the most convenient for the
purpose.
The following description refers to the Figures 3, 4, and 5 of the Drawings,
except when otherwise expressly mentioned. A is the frame in which the
parts of this polishing machine are disposed: B is a vertical shaft having its
bearings in A, and receiving a slow motion through appropriate gearing from
any source of power. An upper and a lower disc C. C. set upon the shaft B
as an axis revolve with it. A number of vertical shafts D, D, pass through
the discs C. C', sliding loosely therein, and rest at their lower extremities on
the springs F, F, which have one end secured to the under side of the lower
disc C. and are provided at their free ends with friction rollers B, which run
upon the track E. This track can be raised or lowered at will to regulate the
pressure of the springs upon the lower ends of the small spindles, thereby
regulating the pressure of the slates against the rubbing bed. as seen in
Figure 4. On the upper end of each shaft D is mounted the disc G, in which
a mortise of size and shape required is arranged to hold the slates to be
ground, or the same object may be obtained by adjustable clamps disposed on
said discs G these mortises or moulds are to be removable for the purpose of
fixing and changing the slates. Each shaft D carries a pinion c which meshes
into the stationary toothed segment provided with internal gear, as shown

page_text: in Figure 5; by this means as the central shaft B is revolved in the direction
of the arrow 1, Figures 3 and 4, the shafts D are carried round B as an axis,
and at same time revolve each round. its own axis in the direction of the
arrows 2, Figures 3 and 4. 1, 1, 1, are upright shafts, two, three, or more in
number, arranged in frame A at equal distances from the shaft B, and without
the discs C, C on the upper ends of these shafts I are mounted the grinding
wheels J, J. J2, of different but graduated grade of grit. Motion is given to
the shafts I in the direction of the arrow 3. Figure 3, by means of belts d, or
by any other suitable method, so that they have a greater velocity than shaft B,
and the slates are pressed by the springs F against the grinding surfaces of
wheels J, J', J. e, e, are sleeves sliding on the shafts D beneath the disc C,
and can be secured as desired by the set screws f: 9 are nuts arranged around
shafts D directly below the sleeves e, so that when the set screw is loosened
the sleeve can be accurately adjusted by means of the nuts g.. thereby regu-
lating the pressure of the springs F upon the slates lying in the discs G,
pressing them against the grinding surfaces of the wheels J. The grinding
wheels may be adjustable on their shaft I, by the like or any appropriate
device. The slates are only intended to revolve around the shafts D as an
axis while subjected to the grinding operation of the wheels J, J, J, and for
this purpose the terminal points of the internal gearing of segment or ring H
are vertically beneath the points of the peripheries of J and J, at which the
discs G first strike, and finally quit the said grinding wheels J, J', J². For
the purpose of beveling or edging the slates they are introduced between the
guides K, K, Figure 6, and slid along the bottom piece L until they reach the
emery wheels M, M, mounted on the vertical shafts m, m. The emery wheels
receive their motion from driving wheel N, or from any suitable source of
power, and have their edges beveled, as shown in Figure 5. They are also
adjustable to enable the edges of the slates to be ground to the thickness
required. Although the shafts m, m, are above described as vertical, and the
wheels M, M, as longitudinal, the arrangement may be reversed if desired.
Having described the nature of this Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is,--
First. The grinding wheels C in combination with the mortised discs F,
shaft E. sleeves b, and levers G, substantially as herein set forth and
described.
Secondly. The revolving grinding wheels J. J', J. substantially as described,
in combination with the discs G revolving on their own axis and around the
axis B, all as herein set forth.

page_text: Thirdly. The shaft D in combination with the springs F and annular
track E, in manner substantially as herein set forth and described.
Fourthly. The revolving beveled edged emery wheels M in combination
with the device for polishing and grinding slate in manner substantially as
and for the purposes above described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto
set my hand and seal, this Ninth day of March, in the year of our
Lord One thousand eight hundred and sixty-eight.
A. M. CLARK. (L.S.)