Year: 1886

page_text: Date of Application, 5th June, 1886.
Complete Left, 31st Dec., 1886.
Complete Accepted, 1st Feb., 1887.
We JOHN CROMBIE and JAMES CROMBIE both of Middlesborough on Tees in the
County of York Contractors do hereby declare the nature of our said Invention to be
as follows:-
Our Invention relates to the means or process of constructing or laying down cement
concrete for pavements, floors or the like and has special reference to the concrete
composed of Portland Cement as a matrix mixed with the annealed slag or conunon
slag of blast furnace fire-brick, granite or other suitable material reduced to small
pieces in the usual manner. Paving or flooring formed of concrete is generally laid
down in one continuous surface covering the whole area of the floor or pavement with
the result that the removal of any part of the floor or pavement whether for the purpose
of renewal or for access to drain pipes or other connnections underlying the concrete
is a matter of difficulty, the concrete at that part being first broken up and afterwards
replaced by fresh concrete and forming a patch. In other cases where the paving or
flooring is laid down in flags or slabs these flags or slabs are first moulded and allowed
to set firm, as for instance in the contractors yard, and are afterwards laid down in
their places in the pavement or floor in the usual manner of paving slabs.
Our object is to supersede these methods of laying down concrete pavements or floors
and to substitute therefor a method of constructing the said pavement, floor, or other
surface in detached slabs or flags moulded or cast and left to set firmly in the positions
which they are intended to occupy as part of the concrete pavement floor or other
surface and by making the detached slabs or flags of convenient dimensions to facilitate
the removal of any part of the pavement and floor as compared with the present system
of a continuous surface, as well as to construct the pavement or floor of detached slabs
without the labour and expense and loss of time involved in the usual method of
moulding the slabs or flags in close moulds and allowing them to set firmly before
placing them in position. Concrete pavements and floors constructed according to
our invention are also better able to resist abrasion or wear and tear of traffic.
In carrying out our Invention we first cover the area to be flagged witha layer of sund,
fine ashes or other porous material suitable for absorbing moisture and for forming a bed

page_text: for the concrete to repose on; we then arrange on this bed a system of moulds by
means of moveable moulding boards which divide up the area into the intended number
of slabs and in order to lay the slabs in close contact with the permanent boundaries
of the concrete pavement or floor such as walls or curbing stones the moulding boards
are laid out so as to correspond with these permanent boundaries and to make
up with them moulding boxes for the intended number of slabs which are
cast or moulded in a state of plasticity in the moulding boxes so formed. In the
process of setting the water or moisture contained in the concrete to make it plastic is
drained off through the sand or other porous material forming the bed of the concrete
instead of being retained in the concrete as is the case when the slabs are cast in the
usual close moulds employed in concrete works; this means of absorbing the moisture
from the concrete allows the slabs to set firmer and in less time with a better surface
for resisting abrasion, the slabs also obtain a uniform support from the layer of sand or
equivalent material forming the bed on which they repose. In order to accelerate the
process of casting slab after slab in close proximity without the slabs adhering to each
other or to curb stones or other surfaces with which they are in contact we pack the
moulds or frames with card-board or other equivalent material so as to form an internal
lining to each mould so that when the mould is withdrawn the card board is left
adhering to the concrete slab and prevents adhesion in the case of the next slab being
cast or moulded in contact with it and prevents the slabs from adhering to curb stones,
walls or other permanent boundaries thus a mould may be formed by moulding boards
fitting up to the edges of adjoining slabs or of curb stones or other vertical surfaces; a
simple arrangement would be to fine moulding boards transversely between the
longitudinal curb stones of the path of street to be payed or the walls of a yard or room
with one or more divisions of boards fixed between the transverse boards according to
the intended dimensions of the slabs or flags, the curb stones or their equivalents
enclosing the outside moulds when one slab is cast the division board is removed and
the slab next adjoining is then cast in contact with it and so on through the series
included between the transverse boards from curb stone to curb stone or from wall to
wall, these flags are then allowed to set or harden sufficiently to retain their shape
before removing the transverso boards. Instead of proceeding with the next transverse
series of slabs which would involve the removal of one of the transverse boards we omit
this series of slabs and proceed to the next the intermediate series being constructed
to alternate with the original series; in this way a whole pavement or floor may be
laid down and ready for use in not more than the time required for the construction
and setting of two adjoining series of slabs. In cases where the slabs have to be cast
in frames without card board or other similar non-adhesive packing we prefer to
construct the frume of the mould with wood and line it with iron, as by this combina-
tion of wood and iron we avoid the tendency of the concrete to adhere to the wood,
and frames so constructed are well adapted to retain the form of a true square or any
other figure required for a good contact of the slabs.
J. HENRY JOHNSON,
47, Lincoln's Inn Fields, London, W.C.,
Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in Laying Down or Constructing Concrete Pavements,
Floors, or the like.
We, JOHN CROMBIE and JAMES CROMBIE of Middlesbrough-on-Tees in the County
of York, Contractors, 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 :—
Our Invention relates to the means or process of constructing or laying down
concrete pavements, floors, or the like surfaces, and has special reference to the
treatment of concrete usually employed as a substitute for ordinary paving flags such
as the concrete composed of Portland cement as a matrix mixed with other material
such as raw or annealed blast furnace slag, fire bricks, granite, whinstone, or the like
material reduced to small pieces.
Pavements, floors, or the like surfaces when formed of such concrete are usually
laid down in one continuous surface covering the entire area, with the result that the
removal of any part of the pavement or floor, whether for the purpose of renewal or
for access to drain pipes or other connections usually underlying pavements or floors,
can only be effected by breaking through the concrete which when afterwards
repaired is filled in with fresh concrete which forms a patch with the old concrete. Or
if the concrete is laid down in separate slabs or blocks the process usually employed
involves the labour, delay, and expense of first moulding the concrete into separate
slabs or blocks, as for instance in the contractors yard, and when they are sufficiently
set to be handled, of laying them down in their intended positions in the pavement
or floor.
The object of our invention is to supersede these methods and to substitute therefor
an improved process which combines the advantages of both the above described
systems, that is to say, the concrete is laid down in the plastic state as in the case of
forming one continuous surface, but is moulded into any required arrangement of
separate slabs or blocks any one of which can be afterwards reinoved and replaced or
another substituted therefor independently of the rest.
In carrying our invention into effect we first cover the area to be flagged or paved
with a layer of sand, fine ashes, or other porous material suitable for absorbing or
draining off moisture and for forming a bed upon which the concrete may be allowed
to set without penetrating into spaces or interstices sufficiently to adhere to its bed,
as would be the case when the bed is formed of broken stones or coarse concrete, our
object being to provide a porous non-adhesive bed suitable for the concrete to repose
on when hard; we then arrange on this bed moveable moulding boards which divide
up the area as the process proceeds into a system of moulds corresponding to the
intended number and arrangement of slabs or blocks of concrete.
In the process of setting the water or moisture contained in the concrete to make
it plastic drains off or is absorbed into the layer of sand or other porous material
which forms the bed under the concrete instead of being retained in the concrete as
in the case of casting the slabs in the usual close moulds employed in concrete works.
This method of absorbing the moisture from the concrete causes the slabs to set firmer
and in less time with a harder and better surface for resisting abrasion and the wear
and tear of traffic, the slabs also obtain a uniform support by being cast in the soft
state upon a layer of sand or similar finely divided material which forms their bed
3

page_text: and which is also practically non-adhesive to the concrete so that any
lifted up without disturbing the material which forms its bed.
slab can be
And in order that our invention may be fully understood we will refer to the
accompanying drawing in which a¹ a³ a³ are separate slabs moulded in position by the
following process; the principal moulding boards are fitted in between the curb
stones or other permanent boundaries c c², ¹ being auxiliary moulding boards
fitting in between the principal boards as required to make up each frame or box
when the slab a' is cast, the auxiliary board d' is removed to and slab a² is then
cast, the auxiliary board d is then removed and slab a³ is cast. In order to prevent
each slab from adhering to any adjoining slab or surface we pack the moulding boards
and other surfaces with card-board or other similar material so as to form a thin
non-adhesive lining or packing round the inside of the mould so that when the slab is
cast card-board packing adheres sufficiently to the soft or plastic concrete to retain its
position and to prevent its contact with fixed surfaces or other slabs with which it
would unite so as to resist its subsequent removal; instead of packing the card-board
up to the moveable moulding hoards it may be packed up to the slab after these
boards are removed so long as actual contact between two adjoining slabs is prevented
by means of the card-board packing.
In order to render the process of casting the slabs as continuous and rapid as
possible, instead of waiting until one set of slabs a¹ a² a³ between two principal
moulding boards are sufficiently set to retain their form without the support of these
boards, we leave these boards in position and proceed to cast another set of
slabs at a aby precisely the same process as already employed in the case of
slabs and so on leaving a space A so as not to remove the principal moulding
boards in each case but removing the auxiliary ones; we afterwards fill up the
alternate spaces A, B, &c. with slabs in the same way except that the auxiliary
moulding boards are fitted in between the sides of the slabs already laid down which
in such cases serve the purpose of the principal moulding boards as described with
reference to casting the set of slabs a¹ a³ a³ or u² u uº.
Where curb stones or other permanent boundaries such as walls are already fixed
in position these are made use of as outside framing between which the principal
moulding boards are fitted, but if it be desirable to also mould the curb stones in
position as well as the slabs we provide outside moulding boards e¹ e as substitutes
for the fixed curb stones or other permanont boundaries and after the slabs are cast,
employ auxiliary moulding boards ff by which means the curb stones may be cast
in suitable lengths between the outside edges of the previously moulded slabs and the
outside moulding board which is moved away from the slabs to the required distance
corresponding to the intended width of the curb stones.
In order to procure clean and sharp edged slabs of concrete, we prefer to line the
moulding boards with wrought iron in every case in which the moulding board comes
into direct contact with the plastic concrete which adheres more to wood than to iron.
It is obvious that the above described process of manipulating the moulding boards
and the precise order in which the slabs are moulded can be varied according to
circumstances without departing from the nature of our invention.
Having now particularly described and ascertained the nature of our invention and
by what means the same may he carried into effect we declare that what we
claim is :-
In laying down concrete pavements or the like surfaces the means and process for
casting the concrete in separate slabs or blocks substantially in the manner and for the
purpose as herein before described.