DIVIDING KNIFE MEANS FOR A SAW MACHINE

LAME DEDOUBLEUSE SUR MACHINE DE SCIERIE

English Abstract

Abstract of Disclosure

A dividing knife means for a saw machine, consisting of at least
one dividing knife located in the saw machine after the sawing
blade , as viewed in the sawing direction of the log , keep-
ing the saw cut open. The dividing knife is a flange rotating
about its axis and of which a segment acts as a part spreading
the saw cut. Therefore, the rotation of the dividing knife reduces
the friction arising by the contact of the log and the dividing
knife. It has specifically been a problem in connection with fixed
dividing knives of prior art that the dividing knife cannot be made
very thick because, acting as a fixed wedge, it impedes the
progress of the log through the machine.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A dividing knife means for a saw machine, consisting of at least one
dividing knife, located in the saw machine after the saw blade as viewed in
the sawing direction of the log, keeping the saw cut open, wherein the
dividing knife is a flange rotating about its axis, a segment of it acting
as a part spreading the saw cut.


2. Dividing knife means according to claim 1, wherein the dividing knife is
freely rotatable about its axis.


3. Dividing knife means according to claim 1, wherein the dividing knife
has been controlled to rotate in an advantageous relation to the forward
speed of the log.


4. Dividing knife means according to claim 1, wherein the dividing knife is
movable on its axis.

Description

i~120~L


D;viding knife means for a saw machine


The present invention concerns a dividing knife means for a saw
machine, consisting of at least one dividing knife located, as
viewed in the direction in which the log is being ripped, after the
saw blade and holding the saw cut open.
1.
Known in the art are elongated fixed dividing knives mounted after
the saw blade as viewed in the direction of sawing. The function of
dividing kn;ves of this kind is to keep the saw cut open, but their
problem ;s that the dividing knife cannot be made very thick in
relation to the thickness of the saw blade, because as a fixed
wedge it impedes the passage of the log through the machine. Eow-
ever, a dividing knife which is too thin compared with the thick-
ness of the saw blade leaves the saw cut so narrow that the saw
blade tends to rub against the log also with parts other than its
cutting edges, for instance with its sides. This in turn causes
heating of the blade and reduction of its rigidity, whereby the saw
cut wil.] be inaccurate and the dimensional accuracy of the sawn
timber deteriorates. In short logs, the saw cut may in fact become
so pinched that the progress of the log in ehe direction of sawing
stops. Particularly problematic are the dividing knives of prior
art in conjunction with curved sawing, in which case the saw blade
or blades due to the crookedness of the log that i.s being sawn are
subject tc a lateral pressure, as viewed in the sawing direction,
against the fixed dividing knife, the friction arising therefrom
retarding the progress through the machine of the timber that is
being processed.

The obJect of the invention is to eliminate the drawbacks menti.on-
ed. The di.viding knlfe of the invention is characteri.zed in thaw
the dividing knife is a flange rotatabl.e about its axis and a seg-
ment thereof serving as a part .spreading the saw cut. By the aid of
the invention, the rotary motion of the dividing knife wi.ll reduce
the friction resulting from the contact between the log and the
.,,,~ ' I

L4

dividing knife, whereby it becomes possible to use thicker dividing
knives than those Tcnown in the art and to achieve for the operation
of the saw blade a wlder saw cut than beFore. Rotating dividing
knives may be used on one side or on both sides of the saw cut.

An advantageous embodiment of the invention is characteriæed in
that the dlviding knire is freely rotatable about its axis. Thus,
the dividing knife derives its rotation from the friction between
tlle saw cut and the dividing knife.

Another embodiment of the invention is characterized in that the
dividing knife has been contro]led to rotate in an advantageous
relation to the speed at which the log is progressing. Therefore
the dividing knife cannot obstnlct the progress of the log; on the
contrary, it aids the forward feeding of the log.

A third embodiment of the invention is characterized in that the
dividing knife is movahle on its shaft. Ilereby the setting of the
dividing knife is adjustahle with ease fGr different sawing opera-
tions, to be proper1y positioned for the saw cut.

The inven,ion is described in the following by the aid of an
example, reference being made to the drawing attached, wherein

Fig. 1 presents the control and working members of a sawing
machine, viewed oh]iquely from above.

Fig. 2 shows the d;v;ding knife means, viewed along the line II-II
in Fig. 1.

The dividing knife means of the sawinK n~achine consists of three
dividing knives 1 above each other, ]ocated in the saw n~achine, as 'i
viewecl in the sawing direction of the ]og 2, after the saw blade 3
and keeping the saw cut open. The dividing knife is a flange rotat-
ing bolt its axis 4 and a segment of which acts as a part
spreading the saw cut.


Since the dividing knives l are rotating about their axis 4, they
reduce the friction caused hy the contact between the loo. and the
dividing knife, whereby thicker dividing kn;ves than those in use
at present can be used and a wider saw cut than before can be
achieved for the operation of ,he saw blade.

It is obvious to a person skilled in the art that different embodi-
ments of the invention may vary within the scope of the claims
presented below. For instance, dividing knives ean be used, as in
the example, on both sides of the saw cut or only on one side of
the saw cut. The number of dividing knives l may vary from one to
several.