IMPROVEMENTS IN CIRCULAR SAWS
Year: 1879

page_text: LETTERS PATENT to Peter Jensen, of 33, Chancery Lane, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN CIRCULAR SAWS," A
communication from abroad by William Augustus Torrey, of Montclair, in the
State of New Jersey, United States of America.
ANA
PROVISIONAL SPECIFICATION left by the said Peter Jensen at the Office of
the Commissioners of Patenta on the 19th June 1879.
"IMPROVE-
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex.
MENTS IN CIRCULAR SAWS." (A communication from abroad by William Augustus
Torrey, of Montclair, in the State of New Jersey, United States of America.)
The saw teeth are of two kinds, one tooth is adapted to plane one side of the
saw cut, 'the next tooth is adapted to remove the wood from the saw cut, the
third tooth is like the first, but it acts to plane the other side of the saw cut.
These teeth alternate around the saw, and the present improvement relates to
the combination of the peculiar teeth herein described, and also to the peculiar
shape that is given to the circular saw plate itself. The saw plate is not of uniform
thickness, the edge of the saw is the thickest, and it is ground so that the thick-
ness gradually decreases from the teeth towards the centre, and then increases
again in thickness, so that the portion of the saw that is clamped between the
collars of the saw arbor is the same thickness as the saw at the teeth, and has
parallel surfaces for the clamping collars to act upon; this prevents the saw
springing and cutting irregularly.
The cutting or planing teeth are elliptical at the ends, and bevelled on the
sides so as to form planing tools that smooth the sides of the saw cut, and the
cutting edges are the same shape at both sides of the point so that the saw can
be revolved in either direction. One of these teeth has its cutting edge at one
face of the saw, and the next similar tooth is at the other face of the saw.
The intermediate teeth which clear out the saw kerf are each made with two
chisel edges formed at the angles of the tooth, the end of the tooth is slightly
concave, and it is wider than the base of the tooth. The edges of this tooth are
nearly radial to the centre of the saw, and are at an inclination to the face of the
B&W, one edge being inclined one way, and the other inclined the other way.
The cutting teeth and clearing teeth acting in either direction, the saw can be
used twice as long as other saws by simply reversing it upon the arbor, and
bringing the other cutting edges into action.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Peter Jensen in the Great Seal Patent Office on the 19th December
1879.
PETER JENSEN, of 33, Chancery Lane, in the County of Middlesex. "IM.
PROVEMENTS IN CIRCULAR SAWS." A communication from abroad by William
Augustus Torrey, of Montclair, in the State of New Jersey, United States of
America.
The saw teeth are of two kinds, one tooth is adapted to plane one side of the saw
cut, the next tooth is adapted to remove the wood from the saw cut, the third tooth
is like the first, but it acts to plane the other side of the saw cut,
These teeth are alternately placed around the saw, and the present improvement
relates to the combination of the peculiar teeth herein described, and also to the
peculiar shape that is given to the circular saw plate itself. The saw plate is not
of uniform thickness, the edge of the saw is the thickest, and it is ground so that
the thickness gradually decreases from the teeth towards the center, and then
increases again in thickness so that the portion of the saw that is clamped between
the collars of the saw arbor is the same thickness as the saw at the teeth, and has
parallel surfaces for the clamping collars to act upon; this prevents the saw
springing and cutting irregularly.
Figure 1 shows the section of the saw and represents the edge 1 as the same
thickness or nearly so as the central portion 2, the intermediate portions are
concave at each side so as to be thinner at 3, 3; Figures 2 and 3 are edge views of
portions of the improved saws, and Figures 4 and 5 are side elevations of portions
of the same.
The cutting or planing teeth a are elliptical or pointed at the ends, as shown by
dotted lines at Fig. 4, and bevelled on the sides so as to form planing teeth that
smooth the sides of the saw cut, and the cutting edges are the same shape at both
sides of the point, so that the saw can be revolved in either direction. One of
theso teeth has its cutting edge at one face of the saw, and the next similar tooth
is at the other face of the saw.
The intermediate teeth b which clear out the saw kerf are each made with two
chisel edges formed at the angles of the tooth; the end of the tooth is alightly
concave at 4, and it is wider than the base of the tooth. The edges of these
cleaning teeth are nearly radial to the center of the saw, and are filed at an
inclination to the surface of the saw, one edge being inclined one way, and the
other inclined the other way.
The cutting and clearing teeth acting in either direction, the saw can be
used twice as long as other saws by simply reversing it upon the arbor, and
bringing the other cutting edges into action.
The saw may be made entirely of the clearing teeth b, or of the clearing teeth b
and cutting teeth a, alternating in sets of two or more of each kind.
What is claimed and to be secured by Letters Patent is,—
First. The clearing teeth b having concave ends and the edges of the teeth inclined,
so that the base of each clearing tooth is narrower than the cutting end, as set
forth.
Second. The saw formed of the teeth a and b, the cutting teeth a having oval or
pointed ends and bevelled on each cutting edge, and the cleaning teeth 6 having
concave ends with cutting edges at their outer angles, and the base of the teeth
being narrower than the outer ends, as set forth.
Third. The circular saw plate having the central portion and the edge of nearly
uniform thickness, and with the intermediate portions made thinner by grinding,
substantially as set forth.

page_text: Fourth. A circular saw having cutting teeth that are rounded at the ends and
beveled in opposite directions, and intermediate cleaning teeth that are widest at
their outer ends, substantially as set forth.
In witness whereof, I, the said Peter Jensen, have hereunto set my hand
and seal, this Eighteenth day of December, in the year of our Lord One
thousand eight hundred and seventy nine.
Dambb
IONADA