IMPROVEMENTS IN FRET SAW MACHINERY A PART OF WHICH IS APPLICABLE TO OTHER MACHINERY
Year: 1884

page_text: I GEORGE JACKSON, late of Dunedin, in the Colony of New Zealand, but now
of Melbourne, in the Colony of Victoria, Woodworker do hereby declare the
nature of my Invention for "IMPROVEMENTS IN FRET SAW MACHINERY A PART
OF WHICH IS APPLICABLE TO OTHER MACHINERY" and in what manuer the same
is to be performed to be particularly described and ascertained in and by the
following statement :—
My improvements in fret saw machinery relate, first, to the saw; second, to the
arms for supporting the saw; and third, to the bearings for supporting the spindle
around which the butt end of the arms are wound.
My improvement in fret saws consists in making them with an enlargement
at each end of sufficient size to form a shoulder for holding them in their
supporting arms.
My improvements in the arms for supporting fret-saws consist first in the
peculiar construction of the upper one, which is made of two lengths of wire each
of which is fastened at its base to the base board or table of the machine, and is
then coiled around its supporting spindle until it reaches the bearing, near its
outer end, when it is carried forward to the point of travel of the saw.
The two
forward ends of these wires are then twisted together, and one is allowed to project
a little farther than the other. This projecting part is bent slightly upward, and
is slit or slotted for the reception of the top end of the saw.
A check chain passes
around each of the forward ends of said wires to prevent them springing upwards
too far in the event of the upper arm which they constitute becoming accidentally
or intentionally disconnected from the saw. My improvements in the arms for
supporting fret saws consist, secondly, in the peculiar construction of the lower
arin which is made of two wires twisted together for a short distance at the one
end and then spread out for a distance of about two and a half to three inches, and
then brought together again, so as to form an oblong slot or hole for the guide or
crank block to slide in. One wire is carried out a little distance beyond the other
(as in the top arm) and beut slightly downward, and into this a slot is cut for
inserting the saw. The other ends of the wires are separately twisted or coiled
into the form of a spiral spring, and their ends fastened or inserted into the
base board, table, or stand. Into the spirals or coils pass a wood or metal
spindle.

page_text: My improvements in the bearings for supporting the spindle around which the
butt ends of the arms are wound, consists of wire twisted into the form of a spiral
of two or more coils, the hole formed in the spiral constituting the bearing. The
ends of these wires are bent over, and eyes are formed in their ends for the passage
of screws with which to fasten them to the table. This is the part of my Invention
which is applicable to other machinery beside fret saws.
Referring to my Drawings Figure 1 shews top view of a fret saw and its
attachments constructed according to this Invention. Figure 2 side elevation, and
Figure 3 view of same turned bottom upwards. Figure 4 shews my fret saw with
the enlargement at the end, and Figure 5 perspective of my novel bearings. The
two wires which form the upper arm are marked A and A¹, the latter having a
slit A at its extremity for the reception of the upper end of the fret saw B, the
enlargement B¹ on which, prevents its slipping through said slit. The two wires
which form the lower arm are marked C and C₁, the latter having a slit C at its
extremity for the reception of the lower end of the fret-saw B, which also has an
enlargement B to prevent its slipping through slit 02. A³ is the supporting
spindle for the upper arm, and A* the coiled wire bearings which support it.
A5 is the check chain herein before referred to. Cis the supporting spindle for
the lower arm, and C the coiled wire bearings which support it. C is the oblong
space for the passage of the crank block D to slide in. This crank block is worked
by the crank spindle D' which rests in coiled wire bearings D2, and is driven by
a strap or cord passing around pulley D³, and receiving motion by treadle or
otherwise as is well understood. D'D' are simply coiled wire collars to prevent
any lateral movement of the crank spindle.
Fret-saw machinery constructed according to this Invention is very cheap, easily
worked, and the saws can be connected and disconnected almost instantaneously.
Having thus described the nature of this Invention and the manner of
performing same I would have it understood that what I believe to be new and
therefore claim as my improvements in fret-saw machinery is :-
First. Constructing the upper arm of two wires coiled around a common spindle
twisted together at their projecting ends, and with a slit in one of them for the
reception of the saw substantially as herein described and explained.
Second. Constructing the lower arm of two wires coiled around a common
spindle and projecting forwards to the line of travel of the saw where the two
wires are twisted together and where the longest one has a slit in it to receive
the saw and behind which there is a slot between them for the travel of the crank
block substantially as herein described and explained.
Third. Constructing fret saws with an enlargement at each end to prevent
them from slipping through their bearings substantially as herein described and
explained.
Fourth. Constructing bearings for the spindles of fret-saw and any other
machinery of coiled wire substantially as herein described and explained.
Dated this Fourth day of April One thousand eight hundred and eighty-four.