IMPROVEMENTS IN SAWING MACHINERY
Year: 1856

page_text: by the Act.)
PROVISIONAL SPECIFICATION left by James Braby at the Office of
the Commissioners of Patents, with his Petition, on the 6th August
1856.
I, JAMES BRABY, of the Borough Haymarket, Newington Causeway, in
the County of Surrey, Wheelwright, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN SAWING MACHINERY," to be as follows:-
My Invention of improvements in sawing machinery relates to improvements
in the construction and operation of various parts of the saw bench of that
description of sawing machinery in which an endless belt of steel with a
serrated edge is employed as the instrument for cutting.
The saw table or bench is furnished with an adjustable centre block, which,
being mounted in a slot or groove, may be moved to and fro therein, and is
provided with an arm for holding the block or piece of timber, which may
then be cut into segments of circles of any given radius within the capacity
of the holding arm.
The timber to be cut is placed on the bench or table in front of the endless
saw, and is kept against the saw by means of the holding arm, which, as the
saw cuts away, is drawn forward, by means of chains and weights or by springs.
When the saw is intended to cut planks from a straight balk of timber of any
considerable length, the timber is drawn forward against the saw (as the latter
cuts) by means of a weighted chain or cord.

page_text: Another improvement consists of an improved construction of fence, which
is moved forward when required by means of a parallel motion. The face of
the fence may be made of various forms, or provided with blocks of various
shapes; for instance, it may have a concave surface suitable for receiving a
block of wood for cutting the felloes of wheels, which block may then be
moved forward by hand in the requisite curve, and the holding arms of the
centre block dispensed with. By constructing the fence with an inclined or
irregularly shaped face, straight diagonal lines or irregular curves may be cut,
and tenons, bevelled or square, may be produced.
When a long length of timber is to be operated upon care must be taken
to keep it tightly pressed against the fence. This object is effected by means
of a spring pressure roller attached to the end of a spring lever, which is
mounted in the screw or socket of the centre block which carries the holding
arm, so that by turning the centre block the spring roller may be made to
.bear more or less strongly against the side of the timber.
-
The next improvements relate to the working of the saw, and consist in the
following contrivances for steadying and guiding the endless saw, and com.
pensating for any stretching or elongation of the belt in consequence of
increased temperature while in operation. The endless saw belt is actuated
by passing over two large pullies, the peripheries of which being made slightly
conical, have a tendency to throw the cutting edge of the saw out of the right
line. To remedy this evil, the saw belt is made to pass over two guide pullies,
one placed above and the other below the bench. The surfaces of these
pullies being made perfectly cylindrical, will correct the evil above mentioned,
and will not only guide or direct the cutting edge of the saw, but will steady
the blade, by preventing the vibration. In order to compensate for any
elongation in the endless saw, in consequence of increased temperature during
the operation of cutting, a tension pulley properly weighted is made to press
against the belt.and tighten it on the driving drums.
It is almost unnecessary to say that the improved sawing machinery with
these improvements adapted thereto is applicable to cutting every description
of wood, stone, and metal, and all kinds of irregular forms and shapes may be
cut thereby.