Year: 1888

page_text: Date of Application, 25th Aug., 1888
Complete Specification Left, 3rd May, 1889-Accepted, 22nd June, 1889

page_text: its centre but are blunt in the middle so as to form together a blunt stud Z Figure 5
at the centre but which does not project beyond the cutting edges.
- This blunt stud Z prevents the cutter from penetrating into the bark w² and
wood w Figure 5 but if in the forward motion of the stem a branch-stump or other
excressence w³ comes in contact with the cutter, it will be cut off.
If however it is also desired to remove the bark by means of this cutter, it is
only necessary to incline the axis of the cutter towards the axis of the stem as shewn
at Figure 5. The blunt stud Z in this case also prevents the cutter from penetrating
into the wood w and serves as guide.
It will be seen that by this inclination of the cutter this will first cut off all
protuberances off the stem and then, as this advances beyond the centre of the
cutter, this will cut off the bark w².
The spindle of the cutter can, by its connection with the lever pivotted at 1
Figure 1, be made to assume a greater or less angle in order to cut off more or less
of the bark. It is however advantageous, only to cut off the outer hard part of the
bark by the rotary cutter.
In order to completely remove the bark with the least possible loss of wood, I
employ revolving disc-brushes mm² m² m³ constructed of a hard elastic material
using by preference steel wire or steel lamin which revolve upon axes nn and are
driven by pullies and which either rest with their entire weight, or partially
balanced, upon the stem so as by their rotation to scrape off the bark, but which do
not attack the wood to an appreciable extent.
There may be one, two, three, or more of such brushes; it is also of advantage,
after having passed the stem under such brushes that revolve in one direction; to
pass it under brushes revolving in the contrary direction, as shewn at Figure 1.
The roller which is connected by levers and links to the spindle of the cutter kas
also the inclined plates gq (which are omitted for the sake of clearness in plan) to
the disc brushes mm have for their object to raise the cutter k and brushes mm¹
automatically to the required height on the introduction of the tree stem.
Dated this 25th day of August 1888.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Machine for Cutting the Bark off Tree Stems and Wood Blocks.
I, LUDWIG PIETTE of Pilsen, Bohemia, Engineer 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 machine for cutting the bark off tree stems
and wood blocks which I will proceed to describe with reference to the drawings
accompanying my Provisional Specification in which Fig. 1 shews a side view of the
machine partly in detail and partly broken off; Fig. 2 shews a plan, Fig. 3 a section
on line Fig. 1. Fig. 4 a section on line y y Fig. 1. Fig. 5 shews a view
to an enlarged scale of the cutter k; Figs. 6 and 7 shew the action of the guide
rollers.
The revolving rollers a a¹bbced carrying the tree stem have their axes
inclined relatively to each other, as shewn, so that the stem is not only made to
revolve upon its own axis, but is at the same time moved forward.
The axes of these guide rollers are inclined at an angle a to the horizontal line,
as shewn at Fig. 7; they revolve in one and the same direction and touch the stem
with the circless and tu which may be considered as parts of oblique helical
surfaces which, in combination, form the screw thread of an imaginary female screw,
the pitch S of which is equal to the distance between the points of contact r and t,
S
and whose diameter D=
S cotanu a.

page_text: The tree stem is caused to rotate by the rotation of the rollers, and as it rests
upon the circles rs and tu, which form parts of a helix as stated, it will at the same
time be advanced thereby at a speed which will depend upon the proportion between
the diameter D' of the stem and the diameter of the helix D, and consequently if
D' be constant, the advance will entirely depend upon the angle a,
cotang a.
as D=
S
tang a
=S
At each revolution of the guide rollers the tree stem will revolve to an extent
equal to s. If the diameter D¹ of the stem were equal to the diameter D of the
helix the forward motion would be equal to the pitch S; but as it is smaller, the
forward notion will be reduced in proportion to the ratio between the diameter of
the helix, and that of the stem, being equal to S
D¹
D.
a and
If therefore stems of different diameters are to be operated upon without varying
the speed of forward feed, it must be rendered possible to vary the angle
consequently the imaginary diameter D of the helix, in order that the proportion, D
may be maintained constant.
D¹
This alteration of the angle a is effected by means of toggle levers and screw gear
as shewn on Fig. 1 of the drawings. By imparting a greater or less inclination to
the rollers, the axial motion of the stem can also be increased or decreased.
For this purpose the bearings of the rollers are mounted upon plates, one end of
each plate of which is rotatable upon the axes gg gg of the worm gear while the
other end is connected to the toggle levers that are actuated by the screw i through
rods connecting them all together, so as to simultaneously raise or lower tho said ends
of the plates.
The stem v passes under the rotary cutter whose shaft is driven by bevil gear,
being arranged to slide with a feather through the tubular-shaft-of-the bevil wheel.
The cutter rests with its weight upon the stem, or it may be pressed down by an
additional weight. The cutting edges of the revolving cutter k do not pass through
its centre but are blunt in the middle so as to form together a blunt stud Z Fig. 5
at the centre, but which does not project beyond the cutting edges.
This blunt stud Z prevents the cutter from penetrating into the bark w² and wood w
Fig. 5, but if, in the forward motion of the stem, a branch stump or other
excressence w¹ comes in contact with the cutter, it will be cut off..
If however it is also desired to remove the bark by means of this cutter, it is
only necessary to incline the axis of the cutter towards the axis of the stem as shewn
at Fig. 5. The blunt stud Z in this case also prevents the cutter from penetrating
into the wood w. and serves as guide.
It will be seen that, by this inclination of the cutter, this will first cut off all
protuberances off the stem and then as this advances beyond the centre of the
cutter this will cut off the bark wo".
The spindle of the cutter can, by its connection with the lever pivotted at 1,
Fig. 1, be made to assume a greater or less angle in order to cut off more or less of
the bark. It is however advantageous only to cut off the outer hard part of the
bark by the rotary cutter.
In order to completely remove the bark with the least possible loss of wood, I
employ revolving disc brushes mm² m² m³ constructed of a hard elastic material,
using by preference steel wire or steel laminae, which revolve upon axes nn and are
driven by pullies oo, and which either rest with their entire weight, or partially
balanced, upon the stem so as by their rotation to scrape off the bark, but which do
not attack the wood to an appreciable extent.
There may be one, two, three or more of such brushes; it is also of advantage,
after having passed the stem under such brushes that revolve in one direction to
pass it under brushes revolving in the contrary direction, as shewn at Fig. 1. The
roller P which is connected by levers and links to the spindle of the cutter k, as also

page_text: the inclined plates (which are omitted for sake of clearness in plan) to the disc
brushes mm have for their object to raise the cutter and brushes mm
automatically to the required height on the introduction of the tree stem.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed I. declare that what I
claim is-
:-
1. In machinery for cutting the bark off tree stems and wood blocks, the use of
rollers for both revolving and feeding forward the steins, the axes of such rollers
being inclined more or less, according to the size of the stems, such inclination being
adjusted by means of suitable gearing so as to render the axial forward motion of
the stems practically constant, notwithstanding the varying diameters thereof, sub-
stantially as herein described.
2. In machinery for cutting the bark off tree stems and wood blocks, the use of
rotary face cutters, the central part of which is formed without teeth so as to limit
the extent to which the cutter penetrates into the bark, such cutter when placed
with its axis perpendicular to the surface of the stem, being made only to cut off the
branches and excressences, while when placed with its axis more or less inclined,
the cutter is made also to remove the bark more or less, substantially as herein
described.
3. In machinery for cutting the bark off tree stems and wood blocks, the use of
revolving disc brushes of hard elastic material, preferably steel wire or laminae, for,
removing the bark from the wood without appreciably attacking the latter, substantially
as herein described.
Dated this 2nd day of M. 1000
ABEL & IMRAY,
Agents for the Applicant.