IMPROVEMENTS IN TABLES USED FOR GRINDING, SMOOTHING, AND POLISHING PLATE GLASS
Year: 1877

page_text: LETTERS PATENT to Hamor Lockwood, of Bradford, near Manchester, in the
66
County of Lancaster, for the Invention of IMPROVEMENTS IN TABLES USED
FOR GRINDING, SMOOTHING, AND POLISHING PLATE GLASS"
Scaled the 4th May 1877, and dated the 9th February 1877
PROVISIONAL SPECIFICATION left by the said Hamor Lockwood at the
Office of the Commissioners of Patents on the 9th February 1877
HAMOR LOCKWOOD, of Bradford, near Manchester, in the County of Lancaster
"IMPROVEMENTS IN TABLES USED FOR GRINDING, SMOOTHING, AND POLISHING
PLATE GLASS"
This Invention relates to the construction of the tables used for grinding, smooth-
ing, and polishing plate glass Hitherto such tables have been made either of wood,
stone, or cast on, which has made them very expensive, and also difficult to get
them to a true and level surface in consequence of their large size, being from
about fifteen to twenty-seven yards square
My Invention consists in making such tables of concrete cement, composed of
Portland cement, burnt coal pit slag, and blue sand fiom copper mines
The mode in which I proceed to construct them is as follows -I make a frame-
work of tunber or other suitable material of the size and depth of table required
I then place a layer therein of the above ingredients mixed in about the following
proportions One hundredweight of heavy Portland cement to about two hundred-
weight each of burnt coal pit slag, and blue sand from copper mines, this layer is
beaten well down, and flattened with suitable tools I next place a second layer of
the same ingredients, but sieved or ground finer than the first, I then finish the top
by a layer (about an inch in depth) of Portland cement mixed with fine sand from
When the whole mass 18
copper mines, and smooth off to a true and level surface
set, the wooden framework can be taken away, which leaves it a solid block,
glass is then laid on in the ordinary manner, and the process of polishing and
the

page_text: grinding continued, These tables may be stationary and supported on a pedestal
or on pillais, or may be set on "trolleys," so as to be capable of being moved about
as required.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Hamor Lockwood in the Great Seal Patent Office on the 9th August
1877.
HAMOR LOCKWOOD, of Bradford, near Manchester, in the County of Lancaster.
"IMPROVEMENTS IN TABLES USED FOR GRINDING, SMOOTHING, AND POLISHING
PLATE GLASS”
This Invention relates to the construction of the tables used for grinding, smooth-
ing, and polishing plate glass Hitherto such tables have been made either of wood,
stone, or cast iron, which has made them very expensive and also difficult to get
them to a true level surface in consequence of then large size, being from about
fifteen to twenty-seven yards square
My Invention consists in making such tables of concrete cement, composed of
Portland cement, and other ingredients, such as burnt coal-pit slag or shale, broken
stones, brickbats, and sand
Such being the nature and object of any said Invention, 1 will now proceed to
describe in detail the manner in which the same is to be or may be performed or
caned into practical effect, and in order that the same may be clearly understood
1 have annexed hereunto a Sheet of Drawings illustrative thereof, and have
marked the same with figures and letters of reference corresponding with those in
the following explanation thereof*
The tables may be made in various forms, and the concrete may be made in
different proportions, but I prefer to build the tables up in the manner represented
in the Drawings, in which Fig 1 is a longitudinal section, Fig 2, a transverse
section, Fig 3, a plan view of a table made according to my Invention.
The table a, a, is supported upon four walls b, b, and a midfeather c, c, the
'walls b, b, being by preference countersunk into the back of the table as shown at
Figs 1 and 2
The mode in which I proceed to construct them is as follows -I make a frame-
work of timber or other suitable material of the size and depth of table required;
I then place a layer therein of concreto, and this layer is beaten well down and
flattened with suitable tools The foundation or body is to be made about four
inches thick in the following proportions, vizt Of four parts of rough burnt
shale, brickbats, or bioken stone, that will pass through a two inch mesh gauge
and two parts of sand and one part of good heavy Portland cement The second
layer is to be formed one inch thick as follows, vizt Of three parts of ballast as
above to pass through a thice quarter inch mesh gauge, and one part of sand, and
one part of heavy dark Portland cement inixed with a sufficient quantity of water.
The third layer is to be formed thi co-eighths of an inch thick, vizt, of clean granite
to pass an eighth of an inch mesh gauge, and one part of heavy daik Portland
cement, and a proper quantity of water The fourth and finishing layer is to be
formed with heavy dark Portland cement and water alone, and trowelled to a
perfectly straight, smooth, and true level surface The whole of the sand used to be
clean and sharp, and the water to be perfectly clean When the whole mass is set
the wooden framework can be taken away, which leaves it a solid block, as shown
in the Drawings, the glass is then laid on in the ordinary manner, and the process of
polishing and grinding continued These tables may be stationary and supported
on a pedestal or on pillars, or may be set on "trolleys" so as to be capable of being t
moved about as required.

page_text: Having now described the nature and object of my said Invention, together with
the manner in which the same is to be or may be performed or carried into practical
effect, I wish it to be understood that I clum as my Invention, the construction
of tables used for grinding, smoothing, and polishing plate glass from concrete
made with Portland cement and other ingredients, substantially as herein-before
particularly set forth.
In witness whereof, I, the said Hamor Lockwood, have hereunto set my hand
and seal, this Eighth day of August, in the year of our Lord One thousand
eight hundied and seventy-seven
HAMOR LOCKWOOD. (LS)