Year: 1889

page_text: Date of Application, 13th Dec., 1889-Accepted, 18th Jan.,
1890
Fig. 8 is a piece of a straight or band saw provided with similar teeth.
Similar letters refer to similar parts in the several views.
The teeth are so formed as to make a perfect shaving cut and hence in making the
kerf they take out shavings instead of breaking the chips into sawdust. The heel of
each tooth is therefore, nearly as far from the centre of the saw as the point―
the angle of the clearance from the line of the cut being only about one or
two degrees.
On one or both sides of each tooth, there is a rib a a which extends from the point
to the heel, or towards it, and is longest in line with the cut, and the outside edges
or corners are beveled off as at b. b. or rounded as shown in Fig. 7. These ribs a a
have each a flat surface that is nearly or quite parallel with the sides of the saw and
projects beyond them one-hundredth of an inch or more. They may be put on both
sides of the same tooth as shown in Figs. 1 and 4 or on one side of one tooth and on
the opposite side of the next etc. as shown in Figs. 2. 3. 5 and 6.
The prime object of beveling or rounding the corners bb is to cause the points or
cutting edge of the teeth to remain sharp and operative a much longer time than they
would with a sharp right angle corner, and also to cause the teeth to cut more freely
and require less power to accomplish a given amount of work.
In applying this form of teeth to the band or straight saw, Fig. 8, the ribs may be
made on both sides of the saw tooth, or on one side of each, as in the circular saw
described but in either case it is preferable to bevel or round the outside corners on
the back of each tooth at b b for the reasons herein above stated.
In other saws there is a point on one or both sides of the cutting edge of each
tooth that widens the kerf for the purpose of preventing the lumber from pressing
against the body of the saw. This is called the "set." With this mode of enlarging
the kerf, it is necessary to slant the back of the tooth at a sufficient angle to break the
chip into sawdust, or the saw is liable to follow the grain or
run out of parallel.
"
In our saw the kerf is enlarged by the ribs, a, a, which effectually prevent it
dodging sideways when it comes in contact with knots or cross grains and enables
us to slant the backs of the teeth at so slight an angle from the line of the cut as to
produce shavings instead of sawdust without causing it to run out of a straight
ine.
"
"

page_text: The ribs a a may be shorter than the back of the tooth when required, and in
some kinds of work may be required to be more prominent on the point or cutting
end than on the back end, but should be beveled or rounded on the outer edge or
corner, at b, b, in order to give durability to the point of the tooth and ease
of cut.
The front of each tooth is made concave with a groove or channel a' for the purpose
of producing a more acute angle on each side of the front or cutting end. By this
device the side edges of the teeth keep sharp for a longer time and the shavings and
dust are less liable to slide out sideways between the saw and the lumber.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A saw provided with teeth whose backs have a clearance of less than three degrees
angle from the line of cut on one or both sides of which are ribs a, a, whose corners
are rounded or bevelled as at b, b, substantially as specified.
2. A saw tooth provided with a rib on its side, a flat surface and bevelled or
rounded corners on its top, extending from the cutting point backward towards the
heel, substantially as specified.
3. A saw-tooth provided with a groove or channel a' extending from the cutting
point down towards the bottom of the throat, substantially as specified.
4. A saw tooth provided with a rounded or bevelled cutting edge, substantially as
specified.
Dated thin 12th day of D
1000
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.