IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING BY MEANS OF CIRCULAR SAWS
Year: 1883

page_text: LETTERS PATENT to Archibald William McMurdo of Scotby near Carlisle
in the County of Cumberland for an Invention of "IMPROVEMENTS IN
;
PROVISIONAL SPECIFICATION left by the said Archibald William McMurdo
at the Office of the Commissioners of Patents on the 4th July 1883.
ARCHIBALD WILLIAM MCMURDO of Scotby near Carlisle in the County of
Cumberland "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING BY
MEANS OF CIRCULAR SAWS"
My Invention relates to apparatus or machinery by which circular saws are
operated the said saws moving forwards as they make the cut and my said
Invention has for its object to so arrange the said machinery or apparatus that
much smaller saws can be used than is possible with machinery or apparatus as
ordinarily arranged for this purpose. According to my said Invention instead of
causing the saw to be mounted upon a swinging holder I mount it upon a slider
capable of a longitudinal movement upon a suitable slide or bed-The apparatus is
arranged so that the rotatory motion is transmitted from a fixed shaft to the saw
by means of driving bands which are kept taut at all positions of the saw during
its travel-To effect this I provide a swing bar or bars or frame so arranged as to
be capable of oscillating upon the first motion shaft and it may be suitably
counterweighted-The first motion shaft is provided with a pulley which by
means of a band transmits motion to a pulley carried by a shaft at the outer end of
the oscillating frame and this in its turn by means of another band transmits
motion to the axle of the saw. The said outer end of the oscillating frame is
connected by rigid ties or bars with the axle of the saw or the slider in which it is
mounted, so that as the said slider moves along its slide as the saw makes its cut
(which movement may be effected by a rack and pinion or any suitable means) the
said oscillating frame turns about its centre and follows the motion so that the
bands are kept taut and give the rotatory motion to the saw during the whole of
its travel.

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Archibald William McMurdo in the Patent Office on the
1st January 1884.
ARCHIBALD WILLIAM MCMURDO of Scotsby near Carlisle in the County of
Cumberland "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING BY
MEANS OF CIRCULAR SAWS"
My Invention relates to Apparatus or Machinery by which circular saws are
operated the said saws moving forwards as they make the cut. According to my
said Invention instead of causing the saw to be mounted upon a swinging holder I
mount it upon a slider capable of a longitudinal movement upon a suitable slide or
bed. The apparatus is arranged so that the rotary motion is transmitted from a
fixed shaft to the saw by means of driving bands which are kept taut at all
positions of the saw during its travel. To effect this I provide a swing bar or
bars or frame so arranged as to be capable of oscillating upon the first motion
shaft and it may be suitably counterweighted. The first motion shaft is provided
with a pulley which by means of a band transmits motion to a pulley carried by a
shaft at the outer end of the oscillating frame and this in its turn by means of
another band transmits motion to the axle of the saw. The said outer end of the
oscillating frame is connected by rigid ties or bars with the axle of the saw or the
slider in which it is mounted so that as the said slider moves along its slide as the
saw makes its cut (which movement may be effected by a rack and pinion or any
suitable means) the said oscillating frame turns about its centre and follows the
motion so that the bands are kept taut and give rotatory motion to the saw during
the whole of its travel.
And in Order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
'
Figure 1 is a side elevation of an apparatus constructed or arranged according to
my Invention. Figure is an end elevation of the portion constituting the
mechanism carrying the belts and Figure 3 is an end elevation of the portion
constituting the parts carrying the saw the said portions being shown detached from
each other in the said figures 2 and 3.
.
The saw A is mounted upon an axle a carried by the slider B which is capable
of being mounted longitudinally in guiding grooves in the slide or bed C carried
by the framing D. The motion of rotation is transmitted to the saw by means of
the belts c and f. G is the first motion shaft which is driven by the pulley g from
any suitable motor. The frame H is capable of oscillating upon the said shaft G as
a centre and is counterweighted at g². The said shaft G carries a pulley g³ over
which the band f passes, the said band also passing over a pulley h carried by a
shaft at the outer end of the frame. H. A pulley h³ which may be in one with
the pulley h) is also provided on the shaft h² the band e passing over this pulley
and also over the pulley a² upon the axle a of the saw. The outer end of the
frame H is connected by the swivelling rigid bar I with the axle of the saw being
also capable of turning or swivelling thereon. The forward movement of the
slider B in its guides in the bed C may be effected by any suitable means such for
example as a rack and pinion movement resembling that of a planing machine or
it may be effected by means of a hand lever as at J. As the saw progresses with
its cut and is moved longitudinally the frame H follows the said Motion and thereby
the pulleys a² and g³ are kept at fixed distances from the pulleys h and h³ and the
bands e and fare kept taut as the saw moves along.

page_text: It will be evident that the oscillating frame may be arranged as a pendulous.
frame hung from an overhead shaft..
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
+
The combination of an oscillating frame a longitudinally guided saw and driving
and transmitting pulleys and bands all arranged substantially as and for the
purpose described and illustrated in the acccompanying Drawings.
In witness whereof I the said Archibald William McMurdo have to this my
Specification set my hand and seal this nineteenth day of December One thousand
eight hundred and eighty three.
ARCHIBALD. WILLIAM. M°MURDO. (L.S.)