Improvements in Saws.
Year: 1889

page_text: Date of Application, 26th Aug., 1889
Complete Specification Left, 27th May, 1890--Accepted, 26th Aug., 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. WIRTH & Co., of Frankfort-on-the-Main, in
the Empire of Germany, acting as agents of Ottstadt & Co., of Kostheim-on-
the-Main, Manufacturers, and Richard Wirth, of 42, Hermannstrasse, Frank-
fort-on-the-Main, Engineer, both in the Empire of Germany.]
Improvements in Saws.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of this invention to be as follows:-
This invention has been suggested by the difficulty, when making the dove-tails
that serve to connect the sides of a box, chest or the like in entirely detaching the
small blocks to form the dove-tail grooves, after they have been severed laterally
from the sides of the dove-tails by sawing. If the said blocks were to be detached
by sawing it was necessary to make in the midst of a plate of wood a saw-cut at an
acute angle to an existing saw-cut.
To enable the saw to commence the cutting wherein the whole difficulty herein-
before referred to has indeed consisted, the blade of the saw is made quite pointed
at the lower end but the necessary strength is imparted thereto, and a point of
application is provided for a tractive force, by a second blade which forms one piece
with the first-mentioned blade and is at the same angle to the latter as will be
formed by the cut to be made with the existing cut, and which is continued below
the point where the teeth begin. To this part is applied the power which moves
the blade.
In a saw for cutting out oblique tenons the two blades are at a right angle to each
other. A small plate serves for accurately guiding the saw.
Another saw,
which is designed to cut the small blocks away so as to form the
grooves between straight dove-tails, has two blades arranged at an acute angle to
each other, a small plate serving as a guide.
The last-mentioned saw cuts off the entire basis of the dove-tail block in one cut,
whilst the aforesaid saw for cutting out oblique tenons must be started twice.
A saw which obviates this inconvenience in the severing of the small blocks to
form grooves between oblique dove-tails, has a toothed projecting part provided on
the blade which, when the work is supported on an inclined plane, will at the end of
the cut bear closely upon the basis of the opposite side, thus cutting off the last
remainder at the bottom.
In this case the guide piece forms a continuous strip and the blade is of equal
breadth throughout.
In order to form a dove-tail groove by means of the saws above described three
cuts were necessary that is to say, two cuts for severing the sides with an ordinary
saw, and one cut with the new saw to detach the bottom part.
A saw blade can be constructed which performs the entire work in one stroke for
straight dove-tails, and in two strokes for oblique dove-tails.
If a plain blade, provided with a toothed edge which forms a straight line from
one end to the other is moved at an acute angle to the said line while the work
remains stationary, the teeth can make a straight cut of the length corresponding to
the distance of the last tooth at one end of the cutting edge from a line extending in
the direction of the movement and passing through the last tooth at the other end
of the said cutting edge. Such a blade may be held in a frame by means of the
upper and lower ends of a strip constituting the rear part of the saw and extending
in the direction of the aforesaid movement, and also the upper end of two other
strips.

page_text: Now the relative movement of the said teeth and their action upon the plate of
wood to be sawed does not change in case the plain saw blade is bent at three places
so that the edges are parallel with the direction of the movement and if the latter
remains the same.
EL
In the present case the blade is bent in such a manner that the cross-section of
the three strips, whose lower extremities include the whole cutting edge of the blade,
will correspond to the boundary line of the dove-tail groove to be cut. The strip
which forms the rear part of the saw and the small strip at the upper end in front
are adapted to bear upon the heads of the neighbouring dove-tails and thus constitute
guide for the saw. As the latter is moved downwardly the teeth of the first of the
aforesaid three strips will cut a side of the dove-tail, then the teeth of the next strip
will cut the bottom of the dove-tail groove and finally the third toothed strip will
entirely sever the small block. In order to obtain an easy movement and a cleaner
cut in the corners of the groove the corresponding teeth may be somewhat steeper
than would otherwise be necessary.
It is intended to use this saw in a frame which will dove-tail the entire edge of a
box in one stroke. The saws are firmly secured to the transverse bar of the frame
through the medium of the ends of the above-mentioned strips.
Another saw which will perform the same work as the one that has just been
described with some practical advantages is of symmetrical shape and inay be
regarded as being composed of two lower halves of saws of the kind above
mentioned.
With this saw the two flanks of a dove-tail groove are sawed at the same time,
commencing at the edge of the board. This obviates the splintering of the last chip
or piece which sometimes occurs when the above-described saw is employed. The
cutting of the bottom part of the groove is likewise effected from both sides. Instead
of arranging the two series of teeth at the edges so that they will meet in the middle
of this bottom one series is suitably made to terminate somewhat deeper whilst the
other series extends a little over the former. In this manner is obtained the necessary
space for the sharpening, and the last chip or piece is cut off clean with greater
certainty. In this case it is preferable that the teeth shall terminate at an acuter
angle.
In the case of oblique dove-tails it is impossible to make the grooves in one saw-
cut, by reason of the different angles which the flanks of the dove-tail form with
the surface of the board. The board must be moved to the saw upon two inclined
feed tables. These have two series of teeth arranged upon planes which are at a
right angle to each other, but which do not differ essentially from those above
described.
The saw blades hereinbefore described are all composed of several planes which
are at an angle to each other, and the transverse section of which corresponds to the
shape of the saw-cut. But there is nothing to prevent the selection instead of the
planes, of cylindrical surfaces of any desired curvature whose axis extends in
the direction of the movement of the saw.
By this means it is rendered possible to make the transverse section of the saw
blade of any shape, composing it of straight or curved lines, with or without corners.
Thus the most general form of the saw blade is obtained that is to say, one which
will cut any desired profile in one stroke. The shape of the saw blade required for
this purpose is characterized by the conditions that the generating lines of the blade
shall be those formed by the desired curve of the cut, whose axis is in the line of
motion, and in which the series of teeth extends in a line which is inclined to the
generating lines of the saw.
In order to obtain a saw which is adapted to make a cut of an irregular shape, a
straight blade made of suitable shape may be bent in a number of places of its width
in the direction of the movement of the saw, and the surfaces thus formed may not
be plain but cylindrical.
With a saw of this kind a fresh cut is preferably commenced by teeth the ground
line of which forms a very acute angle with the axis.
:

page_text: Between the teeth of the cutting edge may be provided a gap or gaps the depth
of which is approximately equal to that of the thickness of the wood to be cut, for
the purpose of preventing the jamming of the saw blade when cutting an acute
re-entering angle. The two series of teeth can be arranged to cut in such a manner
that the point of the profile will also be clean after the saw has been long in use,
and sharpened several times. A wide gap is provided to enable the sharpening of
the uppermost teeth.
Dated this 26th day of August 1889.
HASELTINE, LAKE & Co.,
45. Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Saws.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and Co. Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 was suggested by the difficulty experienced in making the dove-tails
that serve to connect the sides of a box chest or the like in entirely detaching the
small blocks to form the dove-tail grooves after they have been severed laterally
from the sides of the dove-tails by sawing. If the said blocks were to be detached by
sawing it was necessary to make in the midst of a plate of wood a saw cut.
The invention is illustrated in the accompanying drawings, the Figures of which
are hereinafter referred to.
Figures 8 to 11 show in side elevation and perspective two forms of saw blades
which are suitably constructed for this work.
The whole of the difficulty herein before referred to consisted in getting the saw to
commence its cutting action. According to this invention I accomplish this by
making the blade of the saw s quite pointed at its lower end the necessary strength
being imparted thereto and a point of application provided for a tractive force by a
second blade s which forms one piece with the first-mentioned blade s and is at the
same angle to the latter as the cut to be made will form with the existing cut, and
which is continued below the point where the teeth begin. To this part is applied the
power which moves the blade.
Figures 8 and 9 represents a saw for cutting out oblique tenons as shown in
Figures 12 and 14. In this saw the two blades and stare at right angles to
each other. A small plate t serves for accurately guiding the saw.
Figures 10 and 11 show a saw which is designed to cut the small blocks away so
as to form the grooves between straight dove-tails, as shown in Figures 13 and 15.
The two blades s and s¹ form an acute angle to each other, a small plate t serving as
a guide.
The last mentioned saw cuts off the entire basis of the dove-tail block in one cut,
whilst the saw shown in Figures 8 and 9 must be started twice.
Figures 16 and 17 show a saw which obviates this inconvenience in the severing
of the small blocks to form grooves between oblique dove-tails. On the blade is
provided a toothed projection which, when the work is supported on an inclined
plane, as shown in Figure 18, bears at the end of the cut closely upon the basis of the
opposite side, thus cutting off the last remainder at the bottom
In this case the guide-piece t forms a continuous strip and the blade sis of equal
breadth throughout.
In order to form a dove-tail groove by means of the saws above described three cuts
were necessary, that is to say-two cuts for severing the sides with an ordinary saw,
and one cut with the new saw to detach the bottom part.
A saw blade can be constructed which performs the entire work in one stroke for
straight dove-tails, and in two strokes for oblique dove-tails.

page_text: Figures 4, 5 and 6 shows this saw blade in elevation in nine sections and in a
developed state, that is to say the form of a cut and filed sheet or plate in the first
stage of the manufacture of the saw.
If the saw represented in figure 6 is moved in the direction of the chain lines while
the work remains stationary the teeth wil make a straight cut of the length of
b+c+d. In this case the saw blade is held at the upper and lower ends of a strip a
and at the upper end of the strips cand e in a frame.
Now the relative movement of the said teeth and their action upon the wood to be
sawed does not change in case the plain saw blade is bent at three places so that the
edges are parallel with the direction of the movement and if the latter remains
the same.
Figures 4 and 5 show the blade bent in such a manner that the cross-
section of the three strips bd forms the boundary line of the dove-tail groove to
be cut. The strips a and e bears firmly upon the heads of the neighbouring dove-
tails and thus constitute a guide for the saw. As the latter is moved downwardly
the teeth of the strip b will cut a side of the dove-tail, then the teeth of the next
strip c will cut the bottom of the dove-tail, groove and finally the strip d will entirely
sever the small block. In order to obtain an easy movement and a cleaner cut in the
corners of the groove the corresponding teeth may be somewhat steeper than would
otherwise be necessary.
It is intended to use this saw in a frame which will dove-tail the entire edge of a
box in one stroke. The saws are firmly secured to the transverse bar of the frame
through the medium of the ends of the above-mentioned strips a, c, e.
Figures 1 to 3 illustrate a saw which will perform the same work as the one that
has just been described with some practical advantages. This saw is symmetrical in
its shape and may be regarded as being composed of two lower halves of saws of the
kind above mentioned.
Figure 3 shows the form of the plane finished sheet Figures 1 and 2 that of the
finished saw.
With this saw the two flanks of a dove-tail groove are sawed at the same time
commencing at the edge of the board. This obviates the splintering of the last chip or
piece which sometimes occurs when the above-described saw is employed. The cutting
of the bottom part of the groove is likewise effected from both sides. Instead of
arranging the two series of teeth at the edges so that they will meet in the middle
of this bottom one series is suitably made to terminate somewhat deeper as shown in
the figure, whilst the other series extends a little over the former. In this manner is
obtained the necessary space for the sharpening and the last chip or piece is cut off
clean with greater certainty. In this case it is preferable that the teeth shall terminate
at an acuter angle.
Figures 25 to 30 represent a saw for cutting out oblique dove-tails.
It is impossible to make the grooves in one saw cut by reason of the different
angles which the flanks of the dove-tail form with the surface of the board. The board
must be moved to the saw upon two inclined feed tables. These have two series of
teeth arranged upon planes which are at a right angle to each other, but which do not
differ essentially from those above described.
The saw blades herein before described are all composed of several planes which are
at an angle to each other, and the transverse section of which corresponds to the shape
of the saw cut. But there is nothing to prevent the selection, instead of the planes
of cylindrical surfaces of any desired curvature whose axis extends in the direction of
the movement of the saw.
By this means it is rendered possible to make the transverse section of the saw
blade of any shape, composing it of straight or curved lines, with or without corners.
Thus the most general form of the saw blade is obtained that is to say one which will
cut any desired profile in one stroke. The shape of the saw blade required for this
purpose is characterized by the conditions that the generating lines of the blade shall
be those formed by the desired curve of the cut, whose axis is in the line of motion,
and in which the series of teeth extends in a line which is inclined to the generating
lines of the saw.

page_text: In Figures 22, 23 and 24 is represented an example of such a saw blade which is
adapted to make a cut of any irregular shape such as shown in Figure 23. A straight
blade made of suitable shape may be bent in a number of places of its width in
the direction of the movement of the saw, as shown by the chain-lines in Figure 24
the strips b, c, d e f g being generally cylindrical surfaces. This saw blade also
shows at the same time how some difficulties in the construction can be overcome.
With a saw of this kind a fresh cut is preferably commenced by teeth the ground line
of which forms a very acute angle with the axis.
At a gap is provided the depth of which is approximately equal to that of the
thickness of the wood to be cut for the purpose of preventing the jamming of the saw
blade when cutting an acute reentering angle. At K is shown how the two series of
teeth can be arranged to cut one above the other in order to get the point of the
sawed profile cleau after the saw has been long in use and sharpened several times.
p is a wide gap to enable the sharpening of the uppermost teeth.
Having now particularly described and ascertained the nature of the said
invention and in what, manner the same is to be performed as communicated to me
by my foreign correspondents I declare that what I claim is :-
First. A saw for making dove-tail grooves, which consists, of two blades bent at an
angle to each other, one of these blades carrying a series of teeth extending obliquely
to the common axis of the blades, whilst the other blade contained below the com-
mencement of the teeth serves for introducing the saw into an existing cut and as a
point of application of the force more especially at the beginning of the cut.
Second. A saw blade which is bent around parallel axes that form an angle with
the ground line or ground lines of the saw teeth, in such a manner that the transverse
section of the blade is like the contour of a dove-tail groove.
Third. A saw blade which represents in end view the shape of the desired curve
of the cut and in which the ground-line or ground-lines of the saw teeth extend
obliquely to the axis that is to say which have a rising part.
Dated this 27th day of May 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.