Improvements in the Manufacture of Imitation Wood Carvings, and the like, by Pressure and Apparatus therefor.
Year: 1896

page_text: Date of Application, 27th Oct., 1896
Complete Specification Left, 27th July, 1897-Accepted, 2nd Oct., 1897
Improvements in the Manufacture of Imitation Wood Carvings, and
the like, by Pressure and Apparatus therefor.
I, WILLIAM PHILLIPS THOMPSON, of 6, Lord Street, in the City of Liverpool,
Director of Engraved Wood Limited do hereby declare the nature of this invention
to be as follows:-
This invention has for its object the improvement and cheapening of the process
of making pressed wood carvings and in apparatus therefor. These carvings have
hitherto been made in the following manner: Wood is cut across the grain, that is so
that the grain shall stand vertically to the surface, a thin piece of veneer or similar
wood is glued to each side of the slab made in this manner and the slab is placed on a
steel die under a press and pressed into this steel die. In some cases the die is heated,
in other cases the wood is steamed before being placed in the die. Now these wood
carvings are costly to make because the dies are so expensive, large dies frequently
costing from £20 to £50 apiece. The carvings made are also somewhat weak are
liable to warp and only comparatively low relief can be obtained.
Now my invention is designed to overcome these and other evils. In place of using
ordinary dry wood I prefer to use wood artificially dried for the centre slab. I dry it
in the following manner. A cylindrical chamber formed preferably of the rings of an
old boiler has two dished air-tight doors one at each side. It is also provided with
a safety valve weighted to about one tenth of an atmosphere at the top and with a
pipe from the boiler to convey steam. Long balks of wood, preferably three to four
inches square in cross section are loosely piled in this chamber. The chamber is
surrounded by the flue from the boiler furnace or by a flue from any other furnace
and the furnace gases regulated so as to stand at from 130 to 200 Centrigrade
preferably about 170. The wood being placed in the apparatus the doors are closed
and steam is let in to about one pound on the square inch and the safety valve is
regulated so as not to much exceed this pressure. It is steamed in this apparatus,
the steam soon becoming superheated for about four hours after which the steam
is allowed to escape and cold air admitted. When sufficiently cool the wood is
withdrawn and cemented together in balks in the usual manner and cross cut into
slabs. In order to increase the strength of the panels especially when used for screens
or door panels I place a thin sheet of very malleable iron or homogeneous metal
between two equally thick slabs of cross cut wood and outside this the veneer.
It is then placed in the dies to be hereafter described and pressed in the press
until the dies have reached the required depth in the way well understood. It is
impossible to give the exact pressure required as it varies with every pattern and
every kind of wood, but the exact pressure required can be found by testing it on the
first panel or two and the operator need not spoil more than one or at most two pieces
of wood before he finds the right pressure to apply. In order to cheapen the cost
of dies and also to make dies which will produce a much deeper impression than

page_text: those at present employed, and also that will not cause the warping which the present
system causes I use two dies male and female instead of one die and the press surface.
These two dies are arranged so that the elevations of the one correspond to the
depressions of the other or dies of two patterns can be used in which no high relief
in one pattern is opposite the high relief in the other pattern. These two dies are
provided the one with holes and the other with long pegs at their extremities so as to
always exactly register one with another or in place of these pegs and holes, projecting
end or corner plates are attached to one die the other die fitting between these
end plates. By this means the two dies are made to exactly register. The mode
of making my dies differs entirely from the old plan of cutting them out of steel.
I form them of a mixture of lead & antimony with a little bismuth, nickel and arsenic ;
or use other composition that will melt at a reasonable low temperature that will
expand in cooling, that will be sufficiently hard and not too brittle, thus there are
several patent and other type metals which can be made to answer. I cast the die
in the following manner. A pattern of clay, plaster, wood, or other material the exact
design of the panel to be formed is placed below an inverted steel, iron, or other
tough metal box. This box can be either arranged to form part of the mould
or to be used over and over again in casting other moulds. If it form part of the
mould it has screwed projections, dovetail grooves, or the like in it to hold the cast
block perfectly secure. The metal is now run into the box through a suitable hole
means being provided for the air to escape. The air escape holes are then stopped
up and considerable pressure is applied in order to make an accurate casting. This
pressure can be applied in several ways either by running in from a high gate or by
pumping the metal into the mould under considerable pressure. This can be done
by melting the metal in an iron egg and driving in air under pressure, thus driving
the metal out of the egg into the mould or it can be pumped with an ordinary pump
or if the pattern on which the casting is formed is porous such as is the case with
plaster the pressure can be applied by causing a vacuum beneath the plaster by
means of an air pump or lastly all the holes can be stopped up and while the metal
is still fluid the flask or steel box can be pressed with great force down on to the
pattern. In this case I prefer to place an asbestos or other soft packing between
the edges of the box and the pattern so that it will compress and allow the box to
approach the pattern easier or I may use a combination of these plans. In some
instances where it is intended that great pressure should be applied in the formation
of the wood panels or a very large number of repeats have to be taken I form an
electro plated coating of steel or other hard metal on the surface of the pattern before
casting and then cast the type metal on the back of this electroplating afterwards
stripping the electroplating and casting together from the pattern. The pattern in
this case is well blackleaded first, or in some instances where great finish is not
required I am electro-plate a thin coating of hard metal on the cast die after casting.
The press I prefer to use resembles a copying press but I prefer to have two screws
along the centre instead of one and where an air pump is used the lower face of the
press or corresponding face (back) of the pattern is slightly grooved with numerous
grooves radiating to the central hole from which the pipe of the air pump proceeds.
The same air pump can be used for causing a strong air pressure in the egg and a
vacuum below the pattern if desired. When using a thin metal plate in the centre
of the panel a cement should be used which will adhere strongly both to the wood
and to the metal. The veneer or outside layer of wood may in some instances
be coated with copal varnish shellac or other waterproofing varnish a little
before pressing.
.
COUL
1000

page_text: Improvements in the Manufacture of Imitation Wood Carvings, and
the like, by Pressure and Apparatus therefor.
I, WILLIAM PHILLIPS THOMPSON of 6 Lord Street in the City of Liverpool, Director
of Engraved Wood Limited, 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:-
This invention has for its object improvements in and cheapening of the process
of making pressed wood carvings and in apparatus therefor. These carvings have
hitherto been made in the following manner. Wood is cut across the grain, that is,
so that the grain shall stand vertical to the surface. It is then treated with a
toughening solution and a piece of veneer is glued to each side of the slab made in
this manner. The slab is placed on a steel die under a press and pressed into this
steel die. In some cases the die is heated, in other cases the wood is steamed before
being placed in the die. Now these wood panels are costly to make, because the dies
are so expensive, large dies frequently costing from £20 to £50 apiece. The carvings
made are also somewhat weak, are liable to warp, and only comparatively low relief
can be obtained.
Now my invention is designed to overcome these and other evils. In place of using
ordinary dry wood I prefer to use wood artificially dried for forming the centre slab.
I dry it in the following manner. A cylindrical vessel formed preferably of the rings
of an old boiler has two dished air-tight doors one at each end. It is also provided
with a safety valve weighted to about one-tenth of an atmosphere at the top and with
a pipe from the boiler to convey steam this pipe having a stop cock. Long balks
of wood preferably at least three or four inches square in cross section are loosely
piled in this chainber. The chamber is surrounded by the flue from the boiler furnace
or by a flue from any other furnace and the furnace gases are regulated so as to stand
at from 130 to 200 degrees Centigrade, preferably about 170. The wood being
placed in the apparatus the doors are closed and steam is let in at about 1lb. on the
square inch and the safety valve is regulated so as not to much exceed this pressure.
A still lower pressure will do if desired. It is steamed in this apparatus, the steam soon
becoming superheated for about four hours after which the steam is allowed to escape
and cold air admitted. When sufficiently cold the wood is withdrawn and cemented
together in balks in the usual manner and cross cut into slabs. In order to increase
the strength of the panels especially when used for screens or door panels I place a thin
sheet of wire gauze malleable iron or homogeneous metal between two slabs of cross
cut wood and outside this the veneers or in place of a thin sheet of metal I may place
a wirework device or even single wires or bars arranged so as to occupy those parts
of the surface of the slab which are least pressed. The iron can be first embedded
in the slab if desirable. The slab with the iron embedded in it is then placed
between dies hereafter described and pressed in the press until the dies have reached
the required depth in the way well understood. It is impossible to give the exact
pressure required as it varies with every pattern and every kind of wood, but the
exact pressure required can be found by testing it on the first panel or two and the
operator need not spoil even a single panel if he is careful before he finds the right
pressure to apply. In order to cheapen the cost of dies and also to make dies which
will produce a much deeper impression than those at present employed and also that
will not cause the warping which the present system causes, I use two dies one male
and the other female instead of one die. These two dies are arranged so that the
elevations of the one correspond to the depressions of the other, though in some cases
I may use two different patterns in which case however I take care that no high

page_text: relief in one pattern shall be opposite a high relief in the other pattern. These two
dies are provided at their ends one with projections and the other with portions cut
away to fit these projections so that they shall exactly register one with the other or
projecting ends or corner plates are attached to one die as guides or guards, the other
die fitting between or against these guards. By this means the two dies are made to
exactly register. The mode of making my dies differs entirely from the old plan
of cutting them out of steel or iron. I form them of a mixture of lead and antimony
with a little tin, bismuth, and arsenic, the proportions I have used being about 70
of lead 25 of antimony, 2 of tin, 2 of bismuth and 1 of arsenic. I have also sometimes
added a little nickel and copper, these being first melted in a separate crucible before
being added to the other material. There are several hard type metals however which
can be used for this purpose, the main desideratum being a hard metal not too brittle
which shall expand in cooling and melt at a reasonably low temperature.
My invention is illustrated by aid of the accompanying drawings, in which
Fig. 1 is a cross section of a frame pattern and back plate ready for casting.
Fig. 2 back view with the back plate removed.
I form a pattern A of plaster, wood, gutta percha, or waterproof composition, and a
stout iron frame-work B. The pattern the exact size and contour of the panel to be
hereafter made is coated with blacklead and slightly projects into the frame when
clamped. on the same. The joint between the pattern and the frame is made water-
tight. An extremely thin film of copper is electro-deposited all over the surface of the
pattern and over this a thick coating of iron, this coating of iron being also allowed
to attach itself to the lower part of the inside of the frame, the rest of the frame
being coated with paraffine to prevent electro-deposition thereon. The back plate C
is now added and the wide gate D placed in position. The mould is heated to about
130 degrees Centigrade and the type metal cast therein. When it is cold or in some
cases before casting such as when gutta percha is used the pattern is stripped off.
The back plate and the frame-work are generally planed level before casting.
The registering guards are attached to the iron portion of these dies. When
the back plate forms a permanent part of the mould its interior surface and that of the
mould is made as rough as practicable so as to give the type metal greater chance of
adhesion, but in some instances dovetail holes can be cast or otherwise formed in the
metal for this purpose. In some instances however I may have the back plate not a
permanent portion of the mould but simply a perfectly flat planed plate clamped
against the face of the iron frame before casting. When the type metal is cold or
even before it is cold, but is only soft, the back plate is removed by a blow of a
hammer and a surface of type metal remains practically level with the back of the
frame. This can be planed or scraped level if desirable before the mould is used in
the press. In order to prevent the formation of air bubbles in the casting I use a
high broad gate and in some instances especially when casting on a naked plaster
cast I exhaust the air from behind the cast. This is especially useful when a plaster
cast is used without a film of iron or copper. In all instances I find it desirable that
the metal shall be cast under pressure (a high gate is the simplest form) but an iron
egg containing the metal out of which the metal is driven by driving in air under
pressure can be used if desirable. Where a very large number of repeats are required
the electric deposition of iron or other hard metal is necessary, but where only a small
number say a dozen or twenty are required and the mould can then be broken up I
use a naked wooden or plaster pattern and use the type metal surface bare or coated
afterwards with a slight film of iron. When done with, the metal can be melted
off out of the iron frame and both it and the iron frame used for making other dies.
It will be obvious that when an electro-type film is used the backing of type metal
is used purely to fill up the space and that therefore almost any material that would
accomplish this purpose and be sufficiently hard or tough can be used in its place,
thus various forms of paste amalgam which after a time set hard, cement and other
like material can replace the type metal. In practice however these are not so
satisfactory as type metal. In my Provisional Specification I described a press for
pressing the metal while in the liquid state, I have found however in practice that

page_text: this while suitable is not necessary as employing a high gate is all that is required.
These moulds are applicable not merely for imitation wood carvings but for pressing
wood pulp, paper pulp and other materials so as to form embossed wall papers and
other decorations.
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 improved stove and process for treating wood therein for making imitation
wood carvings and the like by pressure, substantially as herein described.
2. In the formation of imitation wood carvings the combination with the wood
placed on end and veneer of a backing or strengthening of metal placed in position
in the wood before the latter is pressed.
3. In the manufacture of pressed wood carvings the combination with blanks
formed of wood on end with veneer surfaces of male and female moulds registering
with each other substantially as described.
4. The improvement in the construction of embossing moulds for the purposes
described which consists in forming them of type metal or other like material such
as described enclosed in an iron, steel or other hard tough metal box and with or
without an electro-deposited film substantially as described.
5. In a mould for ornamenting wood by pressure an electro-deposited surface
of iron or other hard tough metal backed up by other material substantially as
described.
Dated the 26th day of July 1807
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Agents for the Applicant.