Method of and Apparatus for Bending Wood.
Year: 1896

page_text: Date of Application, 11th Apr., 1896-Accepted, 16th May, 1896
COMPLETE SPECIFICATION.
Method of and Apparatus for Bending Wood.
I, JOSEF POLKE of Kohlgasse 26 and 28 Vienna, 5/2, Austria Manufacturer,
do hereby declare the nature of the said invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to the production of wooden cylinders, particularly of such
as are used in the manufacture of barrels for barrel bodies or barrel blanks, and has
for its object an improved method of and apparatus for bending strips or scrolls
of wood, produced by a spiral cut from a log, into cylindrical form.
It is a well known fact, that many kinds of wood, particularly, for instance,
beechwood, when cut into a scroll by a spiral cut, made parallel to the axis of the
log, will not permit the unbending of such scrolls into the form of a cylinder of
larger diameter, without breaking in the direction of the fibre, even when the wood
is in a steamed state.
By my improved method and by means of the improved apparatus appertaining
thereto, I am enabled to unbend spiral scrolls, produced in the manner just
described of any, even the most brittle wood, into cylinders of any desired diameter,
without any breakage occurring.
According to my improved method I euclose the spiral scroll or sheet of wood,
as produced by a spiral cut parallel to the axis of the log, by a metal band of the
same, or nearly the same, width as the sheet of wood. This metal band, which
follows the windings of the wooden spiral, is at one of its ends formed into a hook
by means of which it is attached to the inner end of the wooden spiral. The
wooden spiral, thus enclosed and held at its inner end by the metal band, is, after
having previously been steamed or otherwise softened, placed into a cylinder or
drum, the inside diameter of which corresponds to the diameter of the cylinder
into which the wooden sheet is to be unbent. This cylinder or drum is provided
with a bar traversing its interior close to its inner surface and adapted to be moved
around the inside circumference of the drum. This bar is also provided with a
lip or with other means for holding the free end of the wooden spiral against the
inner surface of the drum. The free end of the wooden spiral being thus held, the
free end of the metal band enclosing it is passed through a slit, to the outside
of the drum, where traction is applied to the metal band. This traction is trans-
mitted by the metal band, the other end of which is hooked over the inner end of
the wooden spiral, to the latter, in consequence of which the free end of the
wooden spiral, that is to say the end which rests against the bar traversing the drum
and is thereby held down against the inner surface of the drum, will receive a
tendency to move around the inner surface of the drum as the wooden spiral is
unbent by the tractional force applied to it. This movement is, however, opposed
to a certain degree by the traversing bar against which the end of the wooden sheet
abuts. This resistance is produced by causing the said traversing bar to recede
around the drum in a slower measure than that of the traction applied to the
metal band. While the traction of the metal band causes an unbending of the
wooden spiral along the inner surface of the drum, a compression of the wood is
produced by the difference between the greater speed of the traction and the
slower yielding movement of the traversing bar. The result of this treatment of
the wood is. that the spiral is unbent into a cylinder or part of a cylinder of the
diameter of the drum without any risk of breaking or cracking the wood.

page_text: The apparatus for carrying into practice the above described method is shown in
the annexed drawing in which
Figure 1 represents the apparatus in side view, partly in section.
Figure 2 is an end view of the apparatus, also partly in section, and
Figure 3 is a plan view, partly in section.
In all figures similar letters of reference indicate corresponding parts.
A is the cylinder or drum which is mounted upon a frame B and which is provided
with a suitable slit in its side for the passage of the metal band C, said slit being
closed by a weighted trap a. Upon the extended frame B is fitted a slide B,
which receives its motion from a screw spindle b. The slide B' is provided with
any suitable device for holding the free end of the metal band C, for instance with
a lever-operated clamping device of the well known kind, as shown.
The traversing bar d is held in its position in the drum A by two dogs D at
either end of the drum, said dogs D being fixed to a spur-collar each, these two
spur-collars E turning upon the ends of the stationary drum A, rotated by two
worms E' in the manner to be hereinafter described.
In Figure 1 the drum A is shown as containing a wooden spiral which bas
already been partly unbent, while its other part, still retaining the spiral form, is
enclosed by the metal band C and is held at its end by the hook c of the metal
band C, the other end of the wooden sheet resting against the bar d and held down
by the projecting rib or lip d¹ of the latter.
In order to keep the wooden cylinders produced in this manner in the form given
to them, until they have been dried or undergone further treatment, I employ the
following device. Into an anunlar recess, with which the drum A is at either end
provided, is placed a strong hoop segment g, so that one of its ends is situated just
above the slit in the drum A through which passes the metal band C. The hoop
segment g extends around the inside of the drum so far that there remains between
its ends an open space somewhat larger than the dogs D which carry the bar d.
This arrangement permits that the hoop segments may be removed from the
drum A. over the bar d and the dogs D, together with the wooden cylinder which
is, for this purpose also left sufficiently wide open at its ends. Inside of and
parallel to each of the segments g a second similar segment g' is rigidly attached to
the former by outside lugs h in such manner that a double hoop segment is formed
having a free annular space, open to the inside of the drum A and wide enough to
fit the thickness of the sheet or board to be unbent.
These double hoop segments being placed into the recess provided in either end
of the drum A, and temporarily fixed in their proper position by any suitable
means, for instance by clamps has indicated in the drawing, the sheet or board as
it is being unbent from the wooden spiral in the described manner will enter the
free space formed between each pair of hoop segments, so that the ends of the
wooden cylinder produced in the apparatus will appear provided with an inside
and an outside hoop formed by the segments. When the wooden spiral, which
must have a predetermined length, has been quite unbent into the form of a
cylinder, that is to say when the ends of the sheet or board have arrived at or
nearly at the ends of the hoop segments, the wood is clamped to the segments by
means of clamps " in order to fix both in their proper position, whereupon the
open wooden cylinders may be removed endwise together with the hoop segments.
For facilitating this removal the segments may be provided with suitable handles
or grips gll as shown.
The two movements for operating the described apparatus, viz. the traction upon
the metal band C and the rotation of the dogs D with the bar d around the drum
may be produced by any known suitable mechanical means. As, however, in the
treatment of different kinds of wood, or even of similar kinds of wood of different
qualities it may become necessary to alter or vary the relative speeds of the
two movements, I employ, by preference, the mechanism shown in the annexed
drawing.
The screw spindle b, which operates the slide B', carries the power pulley I and

page_text: another fast pulley i, which drives the loose pulley upon a shaft k.
l
This loose
pulley may be coupled with the shaft k by means of a clutch . The shaft k
carries a friction wheel m which is attached thereto by a groove and feather so
that its position upon the shaft k may be adjusted.
The hub of the friction wheel m is formed into an extended sleeve at the end of
which is provided a grip ring n, which engages into an annular recess of the hand
wheel o.
The hand wheel o is provided with inside screw thread, by means of
which it is adjustable upon a threaded sleeve p which is rigidly attached to the
bearing of the shaft k.
Thus, by turning the haud wheel o upon the rigid sleeve p the friction wheel m,.
which is coupled to the former by the aforesaid grip ring n, may be longitudinally
adjusted upon the shaft k. When the driven loose pulley is connected with the
shaft k by its clutch ', the friction wheel m will drive the larger friction wheel r
which, when the shaft k is disconnected from the pulley 1, may also be used as a
hand wheel.
The friction wheel r is keyed fast upon a shaft s which is adjustable in its
bearings and is at v provided with a spring for pressing the friction wheel r against
the wheel m. The shaft a drives, by means of the spur wheels and ta shaft u,
which again drives the two shafts e, e, by means of the bevel gears el, el. Upon
'the shafts e, e are keyed the worms E¹, E' which gear into and drive the spur
collars E, E turning upon the ends of the drum A, where they are guided between:
fixed collars wo, w.
From the foregoing construction résults that the speed of the bar d which is
attached to the spur collars E, E by the dogs D may at will be raised or slackened
by adjusting the position of the friction wheel m upon the friction wheel r by
means of the hand wheel o, and that in this manner a lesser or greater compression
may be given to the wood. It further results that, when circumstances require it,
the bar d may also be shifted by hand, by uncoupling the clutch and using the
friction wheel r as a hand wheel.
As has been stated, the wooden cylinders produced in the apparatus are
open, in order to permit their removal from the drum A together with the hoop
segments g. g.
When these hoop segments are taken off, the wooden cylinder will close by its.
own elasticity, for which reason the interior diameter of the drum A must be made
correspondingly larger than that which the finished, that is closed cylinder is to
have.
Having now particularly described and ascertained the nature of my said.
invention and in what manner same is to be performed, I declare that what I
claim is:
1. An improved method of unbending wooden spirals into cylindrical form,.
consisting in placing a metal band around the previously steamed or otherwise.
softened wooden spiral and attaching one end of said metal band to the inner end
of the wooden spiral, placing said spiral into a stationary drum of approximately
the diameter of the cylinder to be formed, unbending the wooden spiral by exerting
a traction upon the free end of the metal band passed to the outside of the drum,.
and, at the same time, producing a compression of the wood by causing the free
end of the spiral to abut against an obstruction in the drum, adapted to yield to the
unbending movement at a speed slower than that of the unbending movement.
caused by the traction of said metel band; substantially as described.
2. An apparatus for carrying into practice the herein described method of
unbending wooden spirals into cylindrical form, formed by the combination with a
stationary drum (A) adapted to receive the wooden spiral, of a metal band (C).
adapted to be attached to the inner end of the wooden spiral, to be passed with its
other end to the outside of the drum (A) and to exert a traction upon the inner
end of the wooden spiral, and of a bar (d) forming an abutment for the other end.

page_text: of the spiral and adapted to be moved around the inside of the drum (A);
substantially as set forth.
3. In apparatus of the kind herein described for unbending wooden spirals into
cylindrical form, the combination with the drum (A), the metal band (C) and the
bar (d) of two cog collars (E, E) carrying the bar (d) and adapted to be rotated
upon the drum (A,) and of means for exerting a traction upon the metal band (C);
substantially as described.
4. In apparatus of the kind herein described for unbending wooden spirals into
cylindrical form, the combination with the drum (A) and the metal band (C) of a
bar (d) having a projection or a lip (d') adapted to hold the wood against the
interior surface of the drum (A); substantially as described.
5. In apparatus for unbending wooden spirals into cylindrical form, the com-
bination with the drun (A) adapted to receive the wooden spiral, of the metal
band (C) adapted to exert a traction upon the spiral, of means for presenting a
yielding obstruction to the unbending of the spiral, and of double hoop seg-
ments (9 g) adapted to be inserted and held in the ends of the drum (A) and to
receive between them the edges of the wood as it is bent into cylindrical form ;
substantially as set forth.
6. In apparatus of the kind herein described for unbending wooden spirals into
cylindrical form, the combination with the drum (A) and the metal band (C) of a
slide (B1) adapted to grip the free end of the metal band (C), and of a screw
spindle for operating said gripping slide (B1); substantially as described.
7. In apparatus of the kind herein described for unbending wooden spirals, the
combination with the drum (A), the metal band (C) and the bar (d) of a friction
wheel (m) adjustable upon its shaft, a second friction wheel (r) adapted to be
driven by the wheel (m), and of an intermediate train of gearing for rotating the
cog collars (E, E) upon the drum (A) from the said wheel. (r); substantially as
described.
Dated the 11th day of April 1896.
PHILIP M. JUSTICE,
London, Chartered Patent Agent,
For the Applicant.