IMPROVEMENTS IN MACHINERY FOR SAWING STONE
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Frederick Samuel Stokes Darby
and William Frederick Hobrow at the Office of the Commissioners:
of Patents, with their Petition, on the 30th August 1873.
We, FREDERICK SAMUEL STOKES DARBY, of Searle's Terrace, Deptford,
in the County of Kent, and WILLIAM FREDERICK HOBROW, of Willes
Road, Kentish Town, in the County of Middlesex, do hereby declare the
nature of the said Invention for “IMPROVEMENTS IN MACHINERY FOR SAWING
STONE," to be as follows :-
This Invention consists in certain combinations and arrangements of
machinery whereby the saw frame is hung and motion given therto,
and other advantages obtained with greater simplicity and efficacy than
by the arrangements hitherto employed.
The machinery is supported by suitable framework provided with the
necessary uprights and braces, and which framework may be constructed
of wood or iron or of the same combined, as may be desired. The saw
frame is suspended at each corner by iron pendulum rods which are
connected at the top thereof to cross beams, which work up and down
between the corner uprights of the framework, the lower ends of the

page_text: pendulum rods being connected to the saw frame by suitable bearings
and joints as will be well understood. The two pendulums at the crank
end of the frame are formed of such a shape as to work clear of the
crank shaft by which motion is given to the saw frame, and thus give
the saw frame and saws an uniform lift at each end, and at every stroke
to allow sand and water to pass under the saws.
The before-mentioned cross beams with the requisite frame attached
thereto are suspended at each corner with chains, or fixed to the same
and passing round drums which are fastened to shafts, by turning which
latter the saw frame when working is lowered by worms which are
keyed on a shaft provided for that purpose. The worm shaft is turned
when the saw frame is in motion by a crank attached to a shaft in
connection with a rod and ratchet wheel.
The saw frame is lifted when the machine is at rest by raising the
pawl of the ratchet wheel and turning a winch by which the before-
mentioned worm shaft is turned by means of a band or chain. This
arrangement also enables the saw frame to be lowered to any required
height. Motion is given to the saw frame by a double crank shaft, tho
cranks being attached to the saw frame by connecting rods, and the
requisite joints and bearings on to the ends of the saw frame. A fly
wheel is fixed to the double crank shaft, the latter being held in bearings
which are fixed to the before-mentioned cross beams between posts.
Motion is imparted to the crank shaft by bevel gearing driven by a
band from the engine. A square shaft passes through the bevel wheel
and the cross beam to allow the saw frame to be moved up and down.
The machinery is thrown out of gear by mcans of a lever which
acts on the bevel wheel, the saw frame being thereby instantaneously
stopped.
By the arrangements above described the same length of stroke is
given to the saw frame at the top as at the bottom of the frame.
For the purpose of supplying sand to the saws the same is placed in a
box suspended from a beam and reciprocated by a crank movement, the
length of stroke to the sand box being regulated by fixing the crank pin
in various parts of the crank arm. Water is supplied through suitable
pipes.
The saws are fixed to plates and are tightened by means of screws
1199
.11 ..

page_text: being fastened to the end of the frame and to a sliding plate by which
arrangement various lengths of saws can be used, according to the
dimensions of the stone to be cut.
By removing the sand box and beam the stones to be cut can be
lifted to the height of the frame, and then lowered into the proper
position on the bed for being sawn, thus dispensing with the necessity for
a trolly to run the stones in and out. A double screw is used to keep
the saw frame level at each end.