Improvements in and connected with Veneers for Casks or Barrels.
Year: 1897

page_text: Date of Application, 18th Oct., 1897-Accepted, 2nd Apr., 1898
COMPLETE SPECIFICATION.
Improvements in and connected with Veneers for Casks or Barrels.
I, CARL WITTKOWSKY, of 121A, Potsdamer Strasse, Berlin, Kingdom of Prussia,
German Empire, 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: -
This invention relates to an improved method of manufacturing veneers for
casks or barrels and has for its object to effect various improvements in the con-
struction of the same, as also to overcome various obstacles hitherto experienced
in the manufacture.
It has already often been tried to manufacture a cylindrical barrel-mantle, or a
barrel or cask mantle of varying diameter by rolling the said mantle from a con-
tinuous piece of wood produced from the stem of a tree by a circular cut around
said stem.
This method however, only was possible when the grains of wood run parallel
to the longitudinal axis of the cask.
The manufacture of barrels or casks in this way produced very often cracks or
splits in the wood and further a barrel or cask with the mantle formed from a
rolled piece of wood of this description could, further, owing to the natural con-
traction and expansion of the wood not be kept constantly tight, as no means
existed to hinder said expansion and contraction in a mantle having its grain
running parallel to the longitudinal axis.
This contraction and expansion would, however, be no disadvantage, if a barrel
mantle could be produced, in which the grain followed the circumference of the
mantle. Here, however, the difficulty was met with, that the grain of the wood
does not allow of expansion on the outer side and contraction on the inner side,
especially if the thickness of the wood is in accordance with the size of the barrel.
In all the cases herein before mentioned it was impossible to obviate the continual
cracking and splitting of the wood.
It should also be borne in mind, that the mantle to be produced does not consist
of a single veneer having a thickness of say ½-1 mm, but of a board or plate,
having a thickness of 6-10 mm or even more.
To roll boards of this thickness in such manner, that the grain runs perpen-
dicular to the longitudinal axis of the barrel, has not been attained up to now
and the object of my invention, therefore, is to overcome the obstacles that have
been in the way of the purpose in question.
In order to make my invention more clear, I refer to the accompanying drawing,
in which similar letters denote similar parts throughout the different views, and
in which:
Figure 1 is a vertical section through a bending machine having two pressing
rollers (c and d) and two bending rollers (a and b):
Figure 2 is a front-view of the two pressing- and heating-rollers;
Figure 3 is a view similar to Figure 2 and showing the rollers ed of Figure 1,
Figures 4, 5, 6, 7 and 9 show longitudinal sections through preliminarily curved
wangan lates

page_text: 17
Cross
In order to better explain my invention, I will give to all the veneers, the grains
of which run across the longitudinal axis of the cask to be formed the term
veneers (marked "e" in Figures 5, 6, 7 and 9), and to all the vencers, the grains
of which run parallel to the longitudinal axis the term "intermediate parallel
vencers" (marked "7" 6, 6 and 9).
To produce a good barrel therefore, the following conditions must be fulfilled:
The cross veneer must not break during the rolling process, consequently the
same must have sufficient solidity in the direction of the longitudinal axis, that it
is impossible for same to come apart in separate rings.
To fulfill these conditions and in carrying my invention into practice, I first
unite to one plate by means of a suitable cementing medium the veneers which I
subsequently intend to roll, in such manner that the inner and outer surface of the
plate consist of cross vencers and the intermediate veneers of the plate of parallel
veneers, see Figures 5 and 6.
The aforesaid manner of arranging the vencers in a cross direction, and uniting
them to a board, is based upon the known fact, that a tension of wood in the direc-
tion of its grain is only possible to a very small extent, whereas its compression in
this direction much greater. The tension and compression of the intermediate
parallel vencers offers no difficulty, whatever.
Proceeding to describe the manufacture of the mantle, I will state, that in order
to avoid unduly straining the grain of the wood by the subsequent rolling process,
it is advisable to impart beforehand to the plates a curved shape, as showif in the
drawing Figures 4-7.
The veneers which are to form the plate, are united under pressure by means
of press-inoulds.
In these press-moulds the veneers become well united under great pressure and
by a simultaneous application of heat. I thus attain a curved plate of a radius
much larger than the one obtained by the subsequent rolling process.
!!
I have now produced a plate, the surface" cross veneers of which have obtained
perfect solidity by the insertion of intermediate parallel veneers, so that the two
surface cross veneer are completely prevented against breaking, on the bending
of the board. The necessary strength and durability of the mantle is thus obtained
and the board may be bent into the proper oylindrical shape, without losing the
least of its resistability in either direction.
Taking into consideration the before mentioned properties of the wood, the rolling
of the plates is now possible for the reason that the compression of the wood (on
hending the preliminarily curved plate into cylindrical shape) is conveyed to the
intermediate parallel veneer or veneers, and to the inner surface cross vencer, whilst
on the other hund the outer surface cross veneers undergo a tension within admis-
sable limits, as in consequence of the particular location of the intermediate
parallel veneer or veneers and of the compressability of the same, the neutral
bending zone is transposed from its usual (middle) position, Figure S, to a position
located between snid usual position and the outer surface-cross-veneer. In order to
obtain and to facilitate the aforesaid tension and flexibility of the outer surface
cross veneer for the rolling process I employ the following method. I first moisten
the outer surface of the plate in any suitable manner and then direct a jet of steam
against it. This takes place before the united plate is passed through the bending
machine, which is subsequently effected in the manner shown in Figures 1-3.
I prefer to make use of four rollers for the bending, a, b, c and d the fourth
roller d being arranged below the middle one & to prevent a tearing of the grain
of the outer veneer.
These two rollers and are heated and form the pressing rollers, whilst and b
are the two bending rollers, and e is a strap which facilitates the passing of the
plates through the rolling machine.
The combined process of employing a plate consisting of veneers crossed, united,
and dried, before steaming, and rolling them between four rollers in the aforesaid
manner, (two of said rollers being heated), has also two other advantages.

page_text: Firstly Trials have frequently been made to unite veneers in a curved or rolled
state by glue, but in such cases the veneers were wound around a drum and were
united whilst in that rolled position.
It was necessary under these conditions to keep the whole surface of the veneers
a long time under pressure upon or against the drum, until the glue became dry,
and it is obvious that this said method must cause a great loss of time, and this
must absolutely exclude a manufacture of barrels on a large scale, by means of
such method.
By my improved method, however, as compared hereto, I give to the plate of
veneers the desired shape or diameter by means of a special process, after their
having been united and dried, and thus effect the manufacture of the cylinder in
one or two minutes.
Further my improved rolling process, has the second advantage, that by adjusting
the rollers a and b, cylinders of any optional diameter may be obtained. I may
also employ three rollers, but I do not prefer this construction.
As herein before mentioned, barrels of varying shape, both cylindrical or bulged,
may be produced by my improved process.
In conclusion I wish it to be understood that I do not limit myself to any especial
shape of the barrel mantle, nor to the use of heated rollers. My invention consists
in the new fact or discovery, that it is possible to roll veneers to a cylinder, the
grains of which run across the longitudinal axis of the cylinder, by uniting the
said veneers to a plate, in such manner, that between the surface veneers, inter-
mediate vencers are located or arranged, said intermediate veneers having their
grain running parallel to the longitudinal axis, and that it is possible, to steam
and roll the said plate after the same has been united and dried; by which
means (.e. by means of my invention), I attain the bending of the plate without
any excessive straining of the wood or the tearing of the grain of such veneers.
I have found that for the uniting of veneers to a plate, it is preferable to employ
heated moulds, and a cementing medium, which becomes waterproof under heat
and pressure, but I do not limit myself to this system of uniting veneers, as any
other cementing medium or glue may be employed for this purpose.
Further I do
not limit myself, that only the grains of the two inner and outer surface veneers
shall run across the longitudinal axis of the cylinder, as shown in Figures 4 and 5,
but another veneer or veneers, the grains of which run in the same direction, may
be located as well next to, or adjoining the said surface veneers, as shown in
Figure 6 or located between the intermediate parallel veneers, as shown in
Figure 7.
It is only indispensable that the inner and outer surface vencer run with the
grain across the longitudinal axis and that one or more intermediate veneers, (the
grains of which run parallel to the longitudinal axis) are located between them.
Having now particularly described the nature of my said invention, and in what
manner the same is to be performed, I declare that what I claim is:-
1. The method of manufacturing veneer-mantles for barrels and casks, con-
sisting in uniting at least two vencers having the same direction of grains, with at
least one veneer arranged between said two and having its grain running perpen-
licular to the grains of said two former veneers, subjecting the veneer-plate thus
formed after its having been united and dried to the action of a jet or steam, and
finally bending the said plate under heat and pressure, in such a manner, that the
grains of the said two former veneers run around the mantle, for the purpose as
described.
2. The method of manufacturing veneer-mantles for barrels and casks, con-
sisting in uniting at least two veneers having the same direction of grains, with at
least one veneer arranged between said two and having its grains running perpen-
dicular to the grains of said two former veneers; moistening the vencer-plate thus
formed, after its having been united and dried; subjecting the said plate to the
action of a jet of steam, and finally bending it under heat and pressure, in such a

page_text: manner, that the grain of the said two former veneers run around the mantle, for
the purpose as described.
3. The method of manufacturing veneer-mantles for barrels and casks, con-
sisting in uniting in a curved state at least two veneers having the same direction
of grains, with at least one vencer arranged between said two and having its grain
running perpendicular to the grains of said two former ones; moistening the curved
veneer board thus formed, subjecting it to the action of a jet of steam, and finally
bending it under heat and pressure, in such a manner, that the grains of the said
two former veneers run around the mantle, for the purpose as described.