IMPROVED APPARATUS OR MECHANISM ESPECIALLY APPLICABLE FOR FILING AND SHARPENING SAWS
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Edward Goddard Durant at the
Office of the Commissioners of Patents, with his Petition, on the
31st January 1871.-A communication from abroad by William
Tucker and Prince Snell, of Fiskdale, Massachusetts, in the United
States of America.
I, EDWARD GODDARD DURANT, of Cockspur Street, Charing Cross,
Westminster, in the County of Middlesex, Manufacturer, do hereby
declare the nature of the said Invention for "IMPROVED APPARATUS OR
MECHANISM ESPECIALLY APPLICABLE FOR FILING AND SHARPENING SAWS," to be as
follows:-
--
This apparatus consists of certain arrangements of wheel gear and
adjustment arrangements whereby circular files or tools may be made
to operate in any suitable position upon the saw required to be treated.
Arrangements being also provided for moving the saw up to its work
and in such degree as may be suitable to the size and form of the teeth
of the saw to be operated upon.

page_text: such guide allowing a carriage for the file or tool to be adjusted in
position by a set screw which secures the said carriage to the guide
plate. The carriage has a bearing for a spindle, to which wheel gear
is attached, by which (on turning a handle connected to such spindle)
motion is given to a circular file or tool, which by the arrangements
aforesaid may be varied in position according to the angle of the tooth
of the saw.
The guide plate is provided with indicator marks for
denoting the position the carriage is to assume in accordance with the
"hook" of tooth. In consequence of the carriage being made with a
bottom plate upon which another plate slides a set screw can be used to
adjust the position of the circular file or tool to a point nearer to or
farther away from the saw according as the depth of tooth may require.
The wheels of the wheel gear can be altered in position and the angle of
the file or tool varied so as to give the desired bevil to the edge of the
saw tooth, an indicator being provided to determine the angle of the
bevil. The frame is provided with stiff springs which support jaws
where a grooved rack can be moved by the action of toothed wheel gear
by means of a suitable handle and pall. The jaws can be adjusted to
the thickness of the saw blade by means of dogs and set screws, the saw
being attached to the grooved rack by small dogs or other suitable
means. The number of teeth to the inch is regulated by having several
different wheels to act with the handle and pall in the rack arrangement,
such wheels being from time to time interchanged according to the
number of teeth to the inch of the saw to be treated. The file or tool is
centred on its spindle and held in position by means of a cone nut.
The whole apparatus can be held in a vice or screwed to a bench when
in use.
The above details are subject to modification in the practical
application thereof, but the following are some important points in the
Invention, namely (in reference specially to saws) :-The circular file
or tool (double countersunk by preference); jaw pieces with capacity
for adjustment parallel with the plane of the saw according to the
varying thicknesses of the blades; in combination with the spring jaw
pieces, the screw clamps or dogs for bringing the jaw pieces to the
required relative adjustments; the carriage having a sliding adjustment
to and from the work, and an adjustment in a horizontal plane to give
more or less "hook" to the teeth, such carriage having a tool stock
capable of adjustment for varying obliquity of teeth; the combination

page_text: of a crank shaft and a concentric sleeve shaft, the former carrying the
driver wheel and the latter furnishing an adjustable stock carrying the
driven pinion and the tool mandrill; driver pinion formed as a hollow
spherical segment, admitting in its concavity a point of the rim of the
rotating tool or file; the grooved rack (or toothed feed bar with a
groove); an arrangement for acting intermittently upon the grooved
rack (or toothed feed bar) which impels the saw plate.