Improvements in Fret-sawing Machines.
Year: 1891

page_text: Date of Application, 7th Oct., 1891
Complete Specification Left, 7th July, 1892-Accepted, 10th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Fret-sawing Machines.
We JAMES MCHARDY of Fairfax House Chiswick Scientific Expert and
WALKER GEORGE DE FORGÉS GARLAND of East Molesey Manufacturer do
hereby declare the nature of this invention to be as follows :-
This invention which relates to improvements in fret-sawing machines is carried
into practice by providing plunging rods of such a form as will preclude the
possibility of their turning in their bearings while at work, and casting either in
the rigid parts which carry them, or separately, such bearings as shall admit of a
sliding up and down motion.
Such bearings may be cast in wood, for example, by boring the wood with a
hole somewhat larger than the plunger which is to be used, but widened at each
end and provided with a key-way: a metalic, core, exactly of the shape of the
plunger, being inserted, the space is filled up with metal, and on the core being
withdrawn, the bearing will be ready for work.
The table of the said fret saw shall be erected, conjointly with the clearance-
frame, upon an upright, capable of carrying all the necessary parts, and having
upon it such cramp or cramps, and other necessary parts, as shall render it possible
to fix the machine to a bench, or table, and if necessary make it rigid with the
floor:
Plungers, to work the saw, moving in the before described bearings, being
provided above and below the table, their upward motion may be procured by a
spring of any suitable kind, whilst their downward motion may be procured by a
centric pulley attached to or connected with the lower plunger, and an eccentric
pulley, driven couveniently, by the power transmitted from the feet in any suitable
manner. To the said eccentric pulley, a small fly-wheel may be united so as to
procure- momentum without a heavy fly wheel for the foot-drive; and any other
parts, found necessary or expedient in carrying these improvements into practice,
may be added, or the driving may be achieved by means of slots, cranks levers &c.;
just-as the tension upon the saw may be regulated in any suitable manner.
·
Instead of the common treadle and crank-drive (which of course may be
applied if preferred-)-we intend to construct a treadle-drive somewhat similar to
that of a bicycle, working a wheel made of wood, glass or any suitable material,
from which the motion will be transmitted by chain, belt, cog and pinion or any
suitable gear. The bearings of the said bicycle-drive will be so constructed as to
be capable of being carried by the single upright, which, as before explained, is
capable of receiving all bearings and: parts which are required, (even a bicycle
saddle pillar) and consequently forms a leading feature in these improvements.
Dated this 5th day of October 1891.
JAMES M'HARDY.
WALKER GEORGE DE FORGÉS GARLAND.

page_text: the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
This invention which relates to improvements in fret sawing machines, is carried
out as follows;
A single piece of material of suitable dimensions is provided with a cramp capable
of fixing the whole to a table or bench in the vertical position.
A suitable foot is so attached as to allow for the varying heights of tables or
benches. For reference we shall call this said upright and attachments above
mentioned, A.
Upon the upper end of A, a suitable table or small saw-bench is fixed and from
any convenient point below the said table a frame piece is carried back, up and,
forward, so as to end over the centre of the saw-bench. The end of this said frame
is prepared by boring a hole (or otherwise) capable of receiving a plunger of such
a shape say square or octagonal-as shall preclude the possibility of its turning.
The bearing for this plunger is most easily formed by pouring in the white metal
upon a core corresponding suitably in size to the plunger. This said plunger is
drawn in the upward direction by a spring, and at its lower extremity it is
provided with a clip for retaining the upper end of the saw which extends down-
wards through the saw bench.
On one side of A (the above described single upright) at a suitable_distance
below the saw-bench a bearing similar to that above described is provided in such
a position as to carry the lower plunger exactly in a line with the upper one.
This said plunger is also provided with a clip to hold the saw by its lowest
extremity.
On the lower end of this plunger a pulley wheel is attached; and at a point still
lower an eccentric pulley runs in the same line upon a spindle carried by a bearing
in A. The said pulleys having a belt upon them, it follows that when the eccentric
pulley revolves it will convey an up and down motion to the plunger.
That is to say; when the eccentric releases the plunger the said plunger will be
actuated in the upward direction by the spring which raises the upper plunger and
in the downward direction by the tightening or downward motion of the eccentric
pulley.
On the same spindle with the eccentric pulley a small fly-wheel is attached which
being actuated by a multiplied motion from a larger driving wheel will supply
momentum without the encumbrance of a heavy driving-wheel.
The driving wheel is preferably actuated after the manner of a bicycle but the
principal advantage we claim is that any bearings or parts we may require, may
all be attached to the single upright A, which in turn may be readily attached to
any table or bench.
Fig. 1-Side elevation of the said invention.
The single unsightl
11

page_text: -A plunger cut across
-metal cast into a prepared hole upon a core or mandrel of the same shape and
size as e.
y-The wood or other material retaining or containing the bearing upon the
main upright.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that
what we claim is ;
1. That construction of a fret sawing machine which enables us to attach all
parts of the said machine to a single upright, as particularly hereinbefore
described.
2. That construction of the slide or plunger-bearings which enables us to cast
them in their required places.
3. The application of an eccentric pulley for driving the saw.
4. The application of a small fly wheel as particularly herein set forth.
5. The application of a bicycle or any suitable drive to fret sawing machines
constructed in such a manner as that all parts are attached to a single upright as
hereinbefore suggested.
Dated this 5th day of July 1892.
JAMES MCHARDY.
WALKER GEORGE DE FORGÉS GARLAND.