IMPROVEMENTS IN ENDLESS OR BAND SAWS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office of
the Commissioners of Patents on the 28th June 1881. A communication
from abroad by Henriette Tuyssuzian, formerly Delong, of Paris, in the
Republic of France.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ENDLESS OR BAND SAWS." A communication
from abroad by Henriette Tuyssuzian, formerly Delong, of Paris, in the Republic
of France.
This Invention relates to certain improvements hereinafter described in the
construction of endless or band saws, whereby they are rendered more adapted for
cutting fret or open work in metal and other materials.
The band saws or endless saws employed for cutting fretwork as heretofore
constructed, present no solution of continuity, so that their application is confined
to cutting external lines or curves, as it is not possible to pass these saws through
holes drilled at any point on a metal plate, for example, as is done when reciprocating
saws are employed.
According to this Invention this disadvantage is obviated by cutting a band or
endless saw, and hooking or joining together the two ends in such a manner as to
restore it to the form of an endless saw.
Important advantages are hereby secured; for example, the saw is enabled to
enter holes drilled in the material at any desired point of the curve or line along
which it is desired to cut, and it is also rendered possible to cut fretwork in plates
of considerable thickness, an operation which could not be performed with
reciprocating saws having necessarily a limited stroke, whereby the parts holding
the saw are rendered liable to strike the work.
The junction of the two extremities of the saw is effected by means of a hook or
interlocking joint.
A portion of the saw near each extremity is reduced in thickness in such a
manner that when the two extremities are superposed or laid together as herein-
after described, the two combined do not exceed the thickness of the remaining
part of the saw. Portions of the back and front at the extreme ends are also
cut away so as to leave narrow tongues at each extremity of tho saw, and these
tongues are provided on opposite sides relatively to each other snugs or hooks
hereinafter referred to.

page_text: In the thin portions hereinbefore described, at the extremities of the saw, there
are formed at equal distances from the tongues two longitudinal slits or openings.
presenting bevelled or inclined surfaces at the edges nearest the ends of the saw,
corresponding exactly to the snugs on the tongues herein before described. The
opposite edge of each opening is also bevelled or inclined, but at a much more acute
angle, so as to form a recess in the side of the saw for the reception of the extreme
end of the corresponding tongue, which is suitably reduced in thickness towards the
extremity in order to enable it to lie well within the said recess.
In order to set up the band saw, that is to say, to join the two ends together.
the two tongues are introduced simultaneously into the two corresponding openings,
and.the ends of the saw are pressed together laterally in such a manner as to cause
the snugs on the tongues to engage with or hook on to the bevelled edges herein-
before described in the said openings, and the thin ends of the tongues then lie
in the inclined recesses in the sides of the saw. When the parts are in this position
the two extremities of the saw cannot bo separated either by considerable strain in
the direction of its length, or by a diminution of the tension.
In order to disconnect the ends of the screw, it is simply necessary to separato
the hooked and bevelled edges by applying lateral pressure, and at the same time
drawing the extremities apart in opposite directions.