Improvements in Double-action Gang-saws.
Year: 1898

page_text: Improvements in Double-action Gang-saws.
I, JOHANNES HEYN, of 6B, Grabower Street, of Stettin, in the Kingdom of
Prussia, German Empire, Engineer, do hereby declare the nature of this inven-
tion to be as follows:.
This invention relates to double action gang-saws and has for its object various
improvements in the construction of the same.
In order to make my invention more clear, I refer to the accompanying
drawing, in which similar letters denote similar parts throughout the several
views.
Saws, which by means of a crank are set in reciprocating motion, so-called
gang-saws, are either arranged horizontally and bear the name of horizontal gang-
saws, or are vertically arranged as employed in a gang-saw-mill and the like.
In the case of horizontal gang-saws, the teeth are, as a rule, in the form shown
in Figure 1 and always cut in two directions in such manner that the teeth
between a and b cut or operate when the saw is actuated in the direction indicated
by the arrow d, whereas the teeth between b and c cut or operate when the saw
moves in the direction indicated by the arrow e.
This result, in the case of horizontal gang saws is, as known, brought about
by the saw receiving a rocking movement in the saw frame on account of the
slides being at a slight angle to the frame, the action being such, that when
the teeth from a to 6 are in use, or, more precisely, are cutting, the teeth from
b to c are lifted from the cutting surface, and inversely when the teeth from b
to c are cutting, then the teeth from a to b are lifted from the cutting surface.
The points of the saw teeth are, however, always in a straight line f-g.
Vertical gang-saws have the teeth arranged, as shown in Figure 2, or, more
precisely, in such manner, that they cut only when the saw descends in the
direction of the arrow h.
In these vertical gang saws the points of the teeth of the saw are also in a
straight line ik, the saw is however so suspended in the gang saw frame, that
it deviates, at an angle lik from the upright line i 7 this deviation, as known,
being for the purpose of lifting the points of the saw teeth from the cutting
surface upon the upward movement of the saw.
The object of my improvements and the object of the present invention is to
produce a saw which shall cut both in a horizontal and in a vertical direction.
and without the necessity of guiding the saw at an angle, as herein before stated
to be requisite in the case of horizontal gang saws.
For this purpose the points of the teeth of my improved saw are no longer arranged
in a straight line, as hitherto, but the line of the teeth point of the one half of the
saw, forms with the line of the teeth points of the other half of the
saw the angle n o p (Figures 3 & 4). The saw is so suspended in the gang saw
frame, that the two teeth-point-lines o p and n o either form an equal or approxi-

page_text: .
mately equal angle nog or por with the upright line q r, that is to say the
angle noq should approximately or entirely equal the angle po r.
It will be therefore clear, that when the saw is operating in a downward direc-
tion or in the direction of the arrow s as shown in Figure 3, the upper teeth on
the line on will cut (or come into operation), whilst the under teeth upon the
line o p must be lifted from the cutting surface, and inversely, when the saw
moves in an upward direction from bottom to top, .e., in the direction of the
arrow t, the teeth of the line op must then come into operation, or cut, and, as
a consequence of this, the teeth of the line on must be lifted from the cutting
surface (Figure 4).
The practicability and success of my improved saw will be quite clear, from
the fact that the same (at one revolution of the crank actuating the, saw) makes
two cuts, whereas in the case of the one-level-saw shown in Figure 2 of the old
kind, the saw would only make one cut.
Also when the saw is equally fed forward, the new form of saw will only
receive one half the amount of tension or load, as in the case of the old form of
saw shown in Figure 2.
My improved saws can therefore be manufactured of less thickness, from which
it is clear that the loss of wood by the lesser width of the cut is therefore
reduced.
Or, should it not be an important factor to reduce the loss of the amount
of wood by cutting, but rather to obtain a higher efficiency, then, if each saw
(Figures 2 & 3) is put into operation at an equal load, my improved forms of
construction of saws, as illustrated in Figures & 4 would show approximately
double the efficiency of the old saws, as the new saws make two cuts at each
revolution of the crank.
The advantages of my improved saws as compared to the saws hitherto known
and shown in Figure 1, consist firstly, that the new saws need not perform the
rocking movement occasioned by the inclined guides, said rocking movement
having, as is known, a great many disadvantages.
The most suitable degree of inclination for the angle n o p, Figures 3 & 4,
is of course dependent upon the kind of wood to be cut and the length of each
feeding motion, or more precisely, the length which the blade is arranged to
advance at each stroke.
Also it will be clear, that the lines no and o p need not necessarily be quite
straight, the same may either be inclined or may form a curve.
Also in the form of the teeth used are optional and are also dependent upon
the kind of wood to be cut etc.
It is also desirable to arrange the stroke of the saw somewhat longer than
the thickness of the tree stem, although it is true, that this cannot always be
effected.
In Figures 3 & 4 the stroke of the saw is shorter than the diameter of the tree
stem A the same is also the case in Figures 5 & 6, whilst in Figures 3 & 4 the
longitudinal recess or slot o at the point where the teeth change, their direction
is so short, that the said slot o does not project beyond the tree stem. If,
however, as in Figures 5 & 6, the slot vw is so long, that the same partly pro-
jects beyond the tree stem A, this is for the purpose of allowing the saw-dust
which accumulates in the slot vw, Figures 5 & 6, being ejected or discharged
in the direction of the arrow s, Figure 5, or in the direction of the arrow t
(Figure 6).
The longitudinal slots vw, Figures 5 & 6, can, however, be so arranged that
they only project beyond one edge of the tree stem.
Also it should be mentioned, that when the lines no and op, as above stated,
are curved in form that then these lines need not form an angle, whereby it will
be clear, that the whole of the saw can follow part of the circumference of a
very wide circle, as shown in Figure 7, in the form of a curve B C and forming
a tangent with the sides of the angle n o p.

page_text: It has been above stated that the new double action gang saw need not have
a reciprocating movement; this is also the case, for the reason that, as will be
clear, the teeth of the saw must, at the change of the stroke, be lifted from the
cutting surface immediately the same are not cutting, even when the teeth are
led straight, that is to say, when the guides are not at an angle to each other.
It is, however, not impossible to impart also to my improved saws a reciprocating
movement, in which case, the teeth of the saw would be twice lifted from the
cutting surface, the first time on account of the new shape of the saws, as herein-
before described and illustrated in Figures 3, 4, 5 & 6, and the second time by
the action of the reciprocating guides of the saw.
That the 10th 1
19ne
I, JOHANNES HEYN, of GB, Grabower Strasse, of Stettin, in the Kingdom of
Prussia, German Empire, Engineer, do hereby declare the nature of this inven-
tion 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 double action gang-saws and has for its object various
improvements in the construction of the same.
In order to make my invention more clear, I refer to the drawing sent in with
Provisional Specification, in which similar letters denote similar parts through-
out the several views.
Saws, which by means of a crank are set in reciprocating motion, so-called
gang-saws, are either arranged horizontally and bear the name of horizontal gang-
saws, or are vertically arranged as employed in a gang-saw mill and the like."
In the case of horizontal gang-saws, the teeth are, as a rule, in the form shown
in Figure 1 and always cut in two directions in such manner that the teeth
between a and b cut and operate when the saw is actuated in the direction indicated
by the arrow d, whereas the teeth between b and c cut or operate when the saw
moves in the direction indicated by the arrow e.
This result, in the case of horizontal gang saws is, as known, brought about
by the saw receiving a rocking movement in the saw frame on account of the
slides being at a slight angle to the frame, the action being such, that when
the teeth from a to b are in use, or, more precisely, are cutting, the teeth from
b to care lifted from the cutting surface, and inversely, when the teeth from b
to e are cutting, then the teeth from a to bare lifted from the cutting surface.
The points of the saw teeth are, however, always in a straight line f-g.
Vertical gang-saws have the teeth arranged, as shown in Figure 2, or, more
precisely, in such manner, that they cut only when the saw descends in the
direction of the arrow h.
In these vertical gang saws the points of the teeth of the saw are also in a
straight line ik, the saw is however so suspended in the gang saw frame, that
it deviates. at an angle ik from the upright line this deviation, as known,
being for the purpose of lifting the points of the saw teeth from the cutting
surface upon the upward movement of the saw.
The object of my improvements and the object of the present invention is to
produce a saw which shall cut both in a horizontal and in a vertical direction

page_text: and without the necessity of guiding the saw at an angle, as hereinbefore stated
to be requisite in the case of horizontal gang saws.
For this purpose the points of the teeth of my improved saw are no longer arranged
in a straight line, as hitherto, but the line of the teeth point of the one half
of the saw, forms with the line of the teeth points of the other half of the
saw the angle n o p (Figures 3 & 4). The saw is so suspended in the gang saw
frame, that the two teeth-point-lines op and n o either form an equal or approxi-
mately equal angle no gor por with the upright line q r, that is to say the
angle should approximately or entirely equal the angle po r.
It will be therefore clear, that when the saw is operating in a downward direc-
tion or in the direction of the arrow s as shown in Figure 3, the upper teeth on
the line on will cut (or come into operation), whilst the under teeth upon the
line op must be lifted from the cutting surface, and inversely, when the saw
moves in an upward direction from bottom to top, .e. in the direction of the
arrow t, the teeth of the line o p must then come into operation, or cut, and, as
a consequence of this, the teeth of the line on must be lifted from the cutting
surface (Figure 4).
The practicability and success of my improved saw will be quite clear, from
the fact that the same (at one revolution of the crank actuating the saw) makes
two cuts, whereas in the case of the one-level-saw shown in Figure 2 of the old
kind, the saw would only make one cut.
Also when the. saw is equally fed forward, the new form of saw will only
receive one half the amount of tension or load, as in the case of the old form of
saw shown in Figure 2.
.
My improved saws can therefore be manufactured of less thickness, from which
it is clear that the loss of wood by the lesser width of the cut is therefore
reduced.
Or, should it not be an important factor to reduce the loss of the amount
of wood by cutting, but rather to obtain a higher efficiency, then, if each saw
(Figures 2 & 3) is put into operation at an equal load, my improved forms of
construction of saws, as illustrated in Figures 3 & 4 would show approximately
double the efficiency of the old saws, as the new saws make two cuts at each
revolution of the crank.
The advantages of my improved saws as compared to the saws hitherto known
and shown in Figure 1, consist firstly, that the new saws need not perform the
rocking movement occasioned by the inclined guides, said rocking movement
having, as is known, a great many disadvantages.
The most suitable degree of inclination for the angle no p, Figures 3 & 4,
is of course dependent upon the kind of wood to be cut and the length of each
feeding motion, or more precisely, the length which the blade is arranged to
advance at each stroke.
Also it will be clear, that the lines no and o p need not necessarily be quite
straight, the same may either be inclined or may form a curve.
Also the form of the teeth used are optional and are dependent upon the kind of
wood to be cut etc..
It is also desirable to arrange the stroke of the saw somewhat longer than the
the thickness of the tree-stem, although it is true, that this cannot always be
effected.
In Figures 3 & 4 the stroke of the saw is shorter than the diameter of the tree
stem A the same is also the case in Figures 5 & 6, whilst in Figures 3 & 4 the
longitudinal recess or slot o at the point where the teeth change, their direction
is so short, that the said slot o does not project beyond the tree stem. If,
ás in Figures 5 & 6, the slot v w is so extended, that the same partly pro-
jects beyond the tree stem A, the saw-dust which accumulates in the
slot vw, Figures 5 & 6 can be ejected or discharged in the direction of the
arrow s. Figure 5, or in the direction of the arrow t, Figure 6.

page_text: The longitudinal slots vw, Figures 5 & 6, can however, be so arranged that
they only project beyond one edge of the tree stem.
Also it should be mentioned, that when the lines no and o p, as above stated,
are curved in form, that these lines need not then form an angle, whereby it will
be clear, that the whole of the saw can follow part of the circumference of a
wide circle, as shown in Figure 7, in the form of a curve B C and form
a tangent with the sides of the angle n o p
It has been above stated that the new double action gang saw need not have
a reciprocating movement; this is also the case, for the reason that, as will be
clear, the teeth of the saw must, at the change of the stroke, be lifted from the
cutting surface immediately the same are not cutting, even when the teeth travel
in a straight direction, that is to say, when the guides are not at an angle to each
other.
It is, however, possible to impart also to my improved saws a reciprocating
movement, in which case, the teeth of the saw would be twice lifted from the
cutting surface, the first time owing to the new shape of the saws, as herein-
before described and illustrated in Figs. 3, 4, 5 & 6, and the second time by the
action of the reciprocating guides of the saw.
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. A double action gang saw, in which the straight or curved lines of the
points of the two inversely operative rows of the teeth of the saw, form an anglen op
for the purpose of lifting the one row of teeth from the cutting surface when the
other row of teeth is cutting, substantially as described.
2. A modified form of the gang saw, characterised in Claim 1, in which con-
struction the angle n o p is substituted by a curve B C (Figure 7), substantially
as described.
3. In connection with the gang saws characterised in Claims 1 & 2, the arrange-
ment of a slot vw (Figures 5 & 6) between the two rows of saw teeth, the said slot v w
being adapted to project either beyond one or beyond both edges of the tree
stem for the purpose of effecting the discharge of the saw-dust, substantially as
described.
T
... 000
ROBERT
DEISSLER,
Agent for the Applicant, 31A, Luisen Strasse, Berlin, N.W., Germany.