Improvements in the Production of Slabs and Blocks for Electrical Insulators and other purposes, and Apparatus to be used in the Manufacture thereof.
Year: 1891

page_text: Date of Application, 2nd Mar., 1891
Complete Specification Left, 2nd Jan., 1892-Accepted, 6th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Production of Slabs and Blocks for Electrical
Insulators and other purposes, and Apparatus to be used in the
Manufacture thereof.
To ALEXANDER MCLEAN of 10 Stonor Road, West Kensington in the County
of Middlesex, Manufacturer, do hereby declare the nature of this invention to be
as follows:-
The object of this invention is to produce slabs or blocks of a material suitable
for various purposes, and especially for use as electric insulators, and which may be
pierced to receive and hold screws, and for other purposes, and otherwise worked,
without chipping, disintegrating, and laminating; and the invention also consists in
the arrangement and construction of apparatus to be employed in the manufacture
of such blocks or slabs.
In carrying out this invention, I take chippings of stone of the formation known
as the great or inferior oolite, and grind up these chippings to fine powder.
I next take Portland cement which has received an extra grinding, and I
intimately mix it dry with the powdered stone in the proportions of two parts of
stone to one part of cement.
When thoroughly mixed dry, 1 work the material up with water in the usual
quantity, and then subject the pasty mass to great pressure in porous moulds in the
press to be hereafter described.
This mixture of stone and Portland cement produces slabs or blocks which can
be bored or pierced with a suitable tool for any purposes that may be required,
without chipping, disintegrating, or laminating, a result which renders it extremely
suitable for insulating slabs for switches, and insulators generally for electrical
purposes.
The material, when mixed in different proportions, say, three of powdered stone
to one of cement, may also be used for other purposes, as, for instance, blocks for
building, as the color is good; it is harder than the natural stone; will "work" as
well as the stone; and will not be subject to deterioration from the effects of the
atmosphere of large towns, to the same extent as the natural stone.
To produce the slabs or blocks, the material in the wet state is placed in a
mould consisting of a rectangular frame of the required size, which is placed upon
or against a flat plate, with a sheet of cotton fabric and a sheet of felt between
them. The filled mould is then conveyed to a hydraulic press in which the material
is subject to enormous pressure.
The felt provides a number of fine channels by which the water can pass freely
away without carrying with it the fine particles of cement etc.
The apparatus consists of a main or foundation casting, which rests upon a
concrete bed, and contains a hydraulic ram. Four threaded bars or guides are
secured to the casting, on which a head slides vertically. The position of this head
on the guides is regulated by means of nuts, according to requirements. This head
also contains a hydraulic ram, the plunger of which has two diameters, as will be
hereafter explained.
The plunger carries a cross head, pendent from which are four adjustable threaded
rods, which project through the head, and are provided at their lower ends with
hooks or projections.
Nuts on the rods determine the amount of motion given to the cross head under
certain circumstances. A plate is fitted to the head so as to be capable of slight
axial motion, & the plate is formed with a series of slots with enlarged circular
ends, through which slots the rods from the head pass. The enlarged circular portions

page_text: are of sufficient diameter to allow the nuts to pass through, but by bringing the
narrow portions of the slots opposite the nuts (the plate is moved axially by a
handle), the movement of the head is arrested when the nuts strike against the
plate.
A block is carried by the ram, and is provided with a trough all round, intended
to catch the water pressed from the material in the mould while under treatment,
and convey it outside the press, for which purpose the trough is provided with
suitable pipes. Upon the block is placed a block of such dimensions that it will
accurately fit into a rectangular frame. This frame will form the sides of the
mould, of which the block will be the bottom. The frame is formed externally with
a groove into which the catches of the pendent rods enter when the mould placed
in the press.
A perforated sheet of metal is placed on the top of the block, with a sheet
of felt upon it, a piece of some suitable (preferably cotton) fabric being laid over
the felt.
The frame is next placed in position, and suitably supported, and when filled, the
mould is pushed into the press. The ram in the foundation casting will of course
be in its lowest position, and the position of the hooks (which will be regulated by
the plate, the nuts bearing against its underside) will be such, that they will freely
enter the groove in the mould frame, as it is pushed into the press.
When the mould is in position, the plate on the head is moved to permit the
passage through it of the nuts, and the ram in the head is set to work. The frame
will thus be drawn up against the underside of the head, and securely held
there. A sheet of felt may be placed over the mould, to ensure a perfect joint
between it and the head.
The main ram is next set to work, and the material in the mould is subjected to
enormous pressure, the water running out in all directions.
When the pressure is completed, the action of the ram is stopped, and the next
operation is to get the compressed material out of the mould.
To effect this, the plate on the head is first moved axially to bring an obstruction
into the path of the nuts; water, is let into the ram cylinder, above the larger
diameter of the plunger, and the ram is forced slowly down, taking with it the
mould frame, which is pushed down by the rods nearly onto the block. The
distance the frame is forced down is regulated by the nuts striking against the plate.
The object of the plate is to keep the frame at a sufficient distance off its seat at
top or bottom, to obviate friction, and allow it to be readily moved in and out of
the press.
When the frame is at the desired position, the main ram is slightly lowered, and
the block and frame with the material are pushed out of the press onto a suitable
table.
The sheet of fabric and felt is then removed from the top, and the block of
material is pushed onto an apparatus of any convenient construction, by which
it can be turned upside down, in order to remove the fabric, felt, and perforated
metal plate. The frame and block are then taken back to a filling table on the
other side of the press by a hydraulic or other crane, or by hand, preparatory to
the mould being refilled.
The block of material produced is then pushed onto another table, from which it
is removed by hand, and taken to a drying shed or store.
Dated this 2nd day of March 1891.
NEWTON & SON,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Production of Slabs and Blocks for Electrical
Insulators and other purposes, and Apparatus to be used in the
Manufacture thereof.
ALEXANDER MCLEAN, of 10 Stonor Road, West Kensington, in the County
of Middlesex, 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 this invention is to produce slabs or blocks of a material suitable
for various purposes, and especially for use as electric insulators, and which may
be pierced to receive and hold screws, and for other purposes, and otherwise worked
without chipping, disintegrating, or laminating, and the invention also consists in
the arrangement and construction of apparatus to be employed in the manufacture
of such blocks or slabs.
In carrying out this invention, I take chippings of stone of the formation known
as the great or inferior oolite, and grind up these chippings to fine powder.
I next take Portland cement of commerce, and subject it to an extra grinding.
and I intimately mix the cement, dry, with the powdered stone, in the proportions
of two parts of stone to one part of cement.
When thoroughly mixed dry, I work the material up with a suitable quantity
of water, and then subject the pasty mass to great pressure in porous moulds in the
press to be hereafter described.
This mixture of stone and Portland cement produces slabs or blocks which can
be bored or pierced with a suitable tool for any purpose that may be required, and
which will hold screws without chipping, disintegrating or laminating; a result
which renders it extremely suitable for insulating slabs for switches, and insulators
generally for electrical purposes.
"
The material, when mixed in different proportions, say, three of powdered stone
to one of cement, may also be used for other purposes, as, for instance, blocks for
building, as the colour is good; it is harder than the natural stone; will "work
as well as the natural stone; and will not be subject to deterioration from the
effects of the atmosphere of large towns to the same extent as the natural stone.
To produce the slabs or blocks, the material in the wet state is placed in a mould
consisting of a rectangular frame of the required size, which is placed upon
or against a flat plate with a sheet of cotton fabric and a sheet of felt between
them. The filled mould is then conveyed to a hydraulic press, in which the
material is subjected to enormous pressure.
The felt provides a number of fine channels by which the water can pass freely
away without carrying with it the fine particles of cement &c.
In the accompanying drawings,
Fig. 1, Sheets I & II, represents in side elevation, partly in section, my complete
apparatus, the right hand half being on Sheet I, and the left hand half on
Sheet II.
Fig. 2, Sheet 111, is a plan view of the feed end or right hand half of the
apparatus.
Fig. 3, Sheet IV, is a front elevation of the press, showing the mould in section.
Fig. 4, Sheet V, is a sectional elevation of the press, taken at right angles to
Fig. 3.
Fig. 5, Sheet VI, is a plan, taken on the line of Fig. 4;
and
Fig. 6 is a plan of the main ram head taken on the line Y y of Fig. 4.
Fig. 7, Sheet II, is a plan view of a reversing apparatus, and
Fig. 8, Sheet III, is a cross section of a carriage with the mould and plunger
therein.
A is a mixing platform, below which is placed a hydraulic ram B. In front of

page_text: the ram, and parallel with the front of the platform, is arranged a railway C'
to receive a carriage D, on which is placed a mould E, to be filled with the mixed
material to be formed into slabs or blocks.
“Centrally of this railway, and at right angles thereto, and opposite to the ram, is
a table F, which I may term the spreading table, onto which the moulds are
pushed by the ram B, and the material which has been thrown in, may be spread
evenly by the attendant, who will also place the felt and fabric on the top of the
spread material.
G is a hydraulic press, which consists of main or foundation casting G, carried
on a concrete bed, and containing a hydraulic ram G. Secured to the casting G,
are four threaded bars or guides H, on which a head G2 slides vertically. The
position of this head G2 on the guides H, is regulated by means of nuts H',
according to requirements. This head contains a hydraulic ram G³, the plunger
of which carries a cross head I, having four pendent adjustable threaded rods 1',
which project through the head G2, and are provided at their lower ends with
hooks or projections (see Fig. 3).
Nuts on the rods determine the amount of motion to be given to the cross
head under certain circumstances. Fitted on the head G, so as to be capable of
slight axial motion, is a plate I, which is formed with a series of slots having
enlarged circular ends, through which slots the rods I from the head pass. The
enlarged circular portions are of sufficient diameter to allow the nuts 13 to pass
through, but by bringing the narrow portions of the slots opposite the nuts (the
plate is moved axially by a handle .J -see Figs. 3 & 5), the movement of the head
is arrested when the nuts strike against the plate.
K is a block, which is secured to the ram G, and practically forms the ram head.
This block K (see Fig. 6) is provided with a trough K' all round, intended to
catch the water pressed from the material in the mould while under treatment, and
convey it outside the press, for which purpose the trough is provided with suitable
pipes K. The block is maintained in a position central of the press by the lugs K³,
which fit against the guides H (see Fig. 6). Upon the block is placed a block L
of such dimensions that it will accurately fit into the rectangular mould E, and this
block L constitutes, in effect, the plunger of the ram G₁. The mould E is composed
of a rectangular frame, formed with an external groove, to receive the catches or
hooks 12 of the pendent rods I' as seen in Figs. 1, 3, 4.
15 are bars or rods secured to, and forming lateral continuations of the hooks I².
These bars or rods serve to support the mould E as it passes to and from the press,
from or to the spreading and receiving tables.
M is a table onto which the slab of concrete or other material which has been
formed, is, with the mould E and block L, pulled from the press G by a chain in
connection with the ram M', below the table, or in other convenient manner; or
the mould may be pushed out of the press by the incoming mould.
N is a reversing apparatus, consisting of two side plates N set apart a distance
a little more than the width of the slabs or blocks to be made, and having
runners Nat top and bottom. The side plates may be strengthened by cross
pieces, and they are pivotted at the centre of their length to a pair of standards N2.
The apparatus is provided with a screw clamping device N by which the slabs,
when slidden onto the runners, will be securely held while the apparatus is being
turned over for a purpose to be presently explained.
O is a table on which the slab of concrete is eventually brought, prior to its
being taken away to be stored.
Pis a hydraulic crane, suitably connected to the press G, and by which the
empty moulds E, with the blocks L, may be moved from one end of the.press to
the other, as required, by means of dogs and suitable chains, or otherwise.
The operation of the apparatus, to produce a slab or block, will be as
follows:-
A mould E, with its block L, is placed on a carriage D at one end of the
railway C (where it may be filled), and is brought in front of the ram B.

page_text: On the top of the block L is placed a perforated metal plate, and this is covered
by a sheet of felt, and a sheet of some suitable (preferably cotton) fabric. The
concrete is mixed on the platform A, and sufficient to fill the mould is thrown in.
The ram B is then set to work to push the filled mould onto the table F, where the
concrete may be evenly spread in the mould by the attendant, who places a sheet
of the cotton fabric on the top of the concrete, and over it, so that it will extend
on all sides beyond the mould (unless it be permanently attached to the press, which
is preferable), a sheet of felt.
During this time, the ram B will be withdrawn, and another mould will be
brought into position to be filled, and forced forward by the ram. When this
takes place, the first mould will be pushed into the press G, the hooks 12 and
the bars or rods I³ entering the grooves in the sides of the mould, and the
position or height of the hooks and bars being regulated by the slotted plate [*
and the nuts I³.
When the mould is in position, the plate 1 is moved axially by the handle J, so
that the nuts I can pass through the enlarged portions of the slots, and the
mould E is drawn up against the underside of the head G2 by the action of the
ram G (the water acting on the underside of a piston connected therewith); a
tight joint is made by means of the felt.
The main ram is now set to work, forcing the block L into the mould E, and
compressing the material therein to the required extent, the liquid or moisture
issuing at the bottom and top.
The slab having been formed, the pressure is relieved, and the mould E is forced
down below the surface of the block L by the hooks I and bars I³, under the
action of the ram G³ (the water being admitted above the piston in connection
therewith), leaving the slab exposed. The plate I and nuts 13 will regulate, as
before (but in the contrary direction), the amount of movement given to the
inould E.
The mould E, with the block L, and the slab, is then pulled out of the press onto
the table M by means of a chain and hook connected with the ram M', or in any
other convenient manner.
The sheet of fabric (and the felt, if separate from the press) is now removed
from the top of the slab, a board is placed thereon, and the slab on its perforated,
plate is pushed into the reversing apparatus N, and is firmly clamped down by the
clamping device. The apparatus N is then turned over, suitable stops heing
provided to support the ends of the frame, and the clamp is released.
The slab can now be pushed out on the board (which rests on the runners) onto
the table O, where the perforated plate, the sheet of felt, and the fabric, are
removed, and the slab is taken away on the board to dry and set.
After the slab is placed in the apparatus N, the mould E and block L are taken
up by the crane P, and transferred to one of the carriages D, to be refilled. The
carriages D are so formed that the frame E will be supported at a higher level
than the block L, but not so high as to clear the block, which will be moved with
and by the frame in a horizontal direction.
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 :-
1. The use, in the production of slabs or blocks suitable for insulating and other
purposes, of powdered stone of the great or inferior oolite formation, and extra
ground Portland cement, as set forth.
2. Producing slabs or blocks, suitable for insulating and other purposes, from
concrete composed of powdered stone of the great or inferior oolite formation, and
extra ground Portland cement, in or about the proportions given, and subjected to
great pressure, to ensure perfect consolidation of the blocks, as set forth.
3. Apparatus for producing slabs or blocks, and consisting of a mixing platform
with hydraulic ram, moulds for receiving the material to be pressed, a hydraulic

page_text: press formed with two rams, means for conveying the filled moulds to the press, a
reversing table, a table (with hauling means) to receive the mould and compressed
material as they leave the press, and means for conveying the mould to the filling
end of the apparatus, all substantially as herein shown and described.
4. A press consisting of a foundation casting containing a hydraulic ram, an
adjustable head containing a second ram, arranged to work in both directions, a
crosshead connected to this ram, adjustable pendent rods carrying supporting pieces,
moulds for containing the material to be compressed, provided externally with
grooves to receive the supporting pieces, and means for ensuring the exit from the
mould of the liquid, and for retaining the solid matter in the mould, all substantially
as herein shown and described.
Dated this 2nd day of Januam 1802
NEWTON & SON,
Agents for the Applicant.