IMPROVEMENTS IN BACK GUIDES OR SUPPORTS FOR BAND SAWS
Year: 1879

page_text: LETTERS PATENT to Charles Denton Abel, of Southampton Buildings, Chancery
Lane, in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
BACK GUIDES OR SUPPORTS FOR BAND SAWS." A communication from abroad
by Carl Pfaff, of Vienna, in the Austrian Empire.
Sealed the 29th July 1879, in pursuance of an Order of the Lord Chancellor, and
dated the 25th January 1879.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 25th January 1879.
CHARLES DENTON ABEL, of Southampton Buildings, Chancery Lane, in the
County of Middlesex. "IMPROVEMENTS IN BACK GUIDES OR SUPPORTS FOR BAND
SAWS." [A communication from abroad by Carl Pfaff, of Vienna, in the Austrian
Empire.]
It is necessary to guide or support band saws both on their entrance into and
exit from the material operated upon, such guiding or support being required at the
side but more particularly at the back edge of the saw, so as to act against the
outward pressure exerted in sawing. As the back edge is necessarily exceedingly
thin great difficulty has hitherto been experienced in affording an efficient and
durable back support, as by the exceedingly rapid action of the blade against the
support this becomes rapidly cut or worn, even when such support is made in the
form of rollers whose axes are at right angles to the saw blade, and which are
rotated by the motion of the latter.
According to the present Invention the above inconvenience is obviated by con-
structing such back support of a rotating body so formed and placed that while it
offers a considerable extent of surface for the back edge of the saw to bear against,
such surface is continually changed by the rotation of the body produced by the
motion of the saw blade. For this purpose the said body is constructed as a roller
whose axis is slightly inclined to the line of the band saw, and is at the same time
slightly to one side thereof, and in order to provide for the contact of the back edge
of the saw along the whole length of the roller the surface of the latter is made
with such a curvature that an oblique line drawn thereon at the same angle to its
axis as the angle which the latter forms with the band saw shall be straight and lie
in a plane parallel to such axis. The roller may be supported in the above described
position in any convenient manner that will afford it perfect freedom to rotate.
Pains 71

page_text: By preference it is mounted on lathe centres in an adjustible bracket, the upper
centre pin being adjustible in the bracket and secured in position by a setting
screw. For the purposes of lubrication a small channel may be conveniently formed
centrally through the upper centre pin and the roller.
_It_will_be_seen_that_owing to the pressure of the band saw being exerted against
_the_roller_slightly_to_one_side_of_its_axis_and_obliquely thereto it will cause_the_
gradual rotation of the roller as it travels past it.
If-desired-two-or-more-such-rollers-may-be-applied-in-combination-as-supports-or-
guides to the saw.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Denton Abel in the Great Seal Patent Office on the 30th
July 1879.
CHARLES DENTON ABEL, of Southampton Buildings, Chancery Lane, in the
County of Middlesex. "IMPROVEMENTS IN BACK GUIDES OR SUPPORTS FOR BAND
SAWS."
A communication from abroad by Carl Pfaff, of Vienna, in the Austrian
Empire.
It is necessary to guide or support band saws both on their entrance into and
exit from the material operated upon, such guiding or support being required at the
side but more particularly at the back edge of the saw, so as to act against the
outward pressure exerted in sawing. As the back edge is necessarily exceedingly
thin great difficulty has hitherto been experienced in affording an efficient and
durable back support, as by the exceedingly rapid action of the blade against the
support this becomes rapidly cut or worn, even when such support is made in the
form of rollers whose axes are at right angles to the saw blade, and which are
rotated by the motion of the latter.
According to the present Invention the above inconvenience is obviated by con-
structing such back support of a rotating body so formed and placed that while it
offers a considerable extent of surface for the back edge of the saw to bear against,
such surface is continually changed by the rotation of the body produced by the
motion of the saw blade. For this purpose the said body is constructed as a roller
whose axis is slightly inclined to the line of the band saw, and is at the same time
slightly to one side thereof, and in order to provide for the contact of the back edge
of the saw along the whole length of the roller the surface of the latter is made
with such a curvature that an oblique line drawn thereon at the same angle to its
axis as the angle which the latter forms with the band saw, shall be straight and lie
in a plane parallel to such axis. The roller may be supported in the above described
position in any convenient manner that will afford it perfect freedom to rotate.
By preference it is mounted on lathe centres in an adjustible bracket, the upper
centre pin being adjustible in the bracket and secured in position by a setting screw.
For the purposes of lubrication a small channel may be conveniently formed centrally
through the upper centre pin and the roller. It will be seen that owing to the
pressure of the band saw being exerted against the roller slightly to one side of its
axis and obliquely thereto it will cause the gradual rotation of the roller as it travels
past it.
If desired two or more such rollers may be applied in combination as
supports or guides to the saw.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews the mode of setting out with approximate accuracy the configu
ration of a roller for the purposes of the said Invention, the proportions of which
will however vary according as the inclination of the axis a, a, may vary. The
circles x1, x2, &c., on plan, Fig. 2, correspond to the dotted sectional lines x, x², &c.
on Fig. 1; Fig. 3 shews a front view and Fig. 4 a side view of a suitable framing
for the roller, which is shewn in vertical section in Fig. 3. The line a, a, represents
the axis of the roller A and the line b, b, the direction of the band saw and its line
of contact with the roller, the curvature of which is such that a line drawn upon
its surface in the direction of b, b, will be a straight line, so that the back edge of
the saw will be in contact with its surface along its entire length. It will be scen
that by the downward motion of the saw blade a slow rotary motion will be
imparted to the roller A owing to the oblique direction in which the saw blade acts
upon it, whereby a fresh surface will be continually presented to the saw blade, thus
preventing the surface of the roller from becoming grooved by its action. Fig. 5
T
1
The
Fig. 1 shews the mode of setting out with approximate accuracy the configu
ration of a roller for the purposes of the said Invention, the proportions of which
will however vary according as the inclination of the axis a, a, may vary.
circles x1, x2, &c., on plan, Fig. 2, correspond to the dotted sectional lines x1, x², &c.
on Fig. 1; Fig. 3 shews a front view and Fig. 4 a side view of a suitable framing
for the roller, which is shewn in vertical section in Fig. 3. The line a, a, represents
the axis of the roller A and the line b, b, the direction of the band saw and its line
of contact with the roller, the curvature of which is such that a line drawn upon
its surface in the direction of b, b, will be a straight line, so that the back edge of
the saw will be in contact with its surface along its entire length. It will be scen
that by the downward motion of the saw blade a slow rotary motion will be
imparted to the roller A owing to the oblique direction in which the saw blade acts
upon it, whereby a fresh surface will be continually presented to the saw blade, thus
preventing the surface of the roller from becoming grooved by its action. Fig. 5
phews a part front view of a band saw machine to a smaller scale with the before

page_text: described Invention applied thereto. The lateral guides for the band saw may be
of any known arrangement.
Having thus described the nature of the said Invention, and in what manner
the same is to be performed, as communicated to me by my foreign correspondent,
I claim,
The use.for guiding or supporting-the-back edge of a band-saw of one-or-more-
rollers or rotating bodies whose axis of rotation is slightly inclined to the direction
-of-the-band-saw,-and-which-is-or-are-so-constructed-and-arranged as to receive a
rotary motion from the motion of the band saw, substantially as and for the purposes
herein-described.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Twenty-fourth day of July, in the year of our Lord One'
thousand eight hundred and seventy ninc.
CITTAR T
ADRI
CHAR. D. ABE
BEL.
15.)