IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING OR DRESSING STONE."
Year: 1870

page_text: LETTERS PATENT to Robert Girdwood, of Edinburgh, in the County
of Mid Lothian, North Britain, Merchant, for the Invention of
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING OR DRESSING
STONE."
PROVISIONAL SPECIFICATION left by the said Robert Girdwood at the
Office of the Commissioners of Patents, with his Petition, on the
18th March 1870.
I, ROBERT GIRDWOOD, of Edinburgh, in the County of Mid Lothian,
North Britain, Merchant, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CUTTING OR
DRESSING STONE," to be as follows, that is to say:-
This Invention relates in part to improvements in machinery or
apparatus of the kind described in the Specification of Letters Patent
granted to Andrew Mitchell, and dated 8th March 1869 (No. 704), and
in part to improvements also applicable to other kinds of machinery or
apparatus for cutting or dressing stone.

page_text: In applying the present improvements to a machine arranged for
operating with a transverse row of tools or cutters, so as to simulta-
neously dress the entire breadth of a block of stone, traversing longitu-
dinally beneath them, a strong transverse beam is provided, which is
made or fitted with a series of guides for the front ends of the several
cutter holders, the latter being jointed to blocks working in the guides.
This guide beam is carried by side frames, in connection with which it
can be adjusted by screws so that the guides may be set to the angle
required for the desired kind of cutting action. The side frames arc
fitted to the main frame standards, so that they can be raised or lowered
by screws or eccentrics for lifting the cutters out of work, or for ad-
justing the level at which they act. The back end of each cutter holder
is jointed to a rod swinging from a transverse horizontal shaft, which is
by preference directly over the guide beam, and for the purpose of
adjustment each rod is made in two pieces with a screw coupling and
reversed screw threads. The hammer blocks are fitted with a screw
adjustment upon levers which swing from a second transverse horizontal
shaft a little behind the first, and the levers are acted upon by short
levers on the same shaft, and worked by cams or wipers on a parallel
revolving shaft.
In some cases the hammer levers are connected by jointed links to the
pistons of air cylinders, the air in which is used as a spring to intensify
the force of the blows. The air cylinders are fitted with stop-cocks to let
out the air, and if this is done when a hammer is raised and the cock
then closed the hammer will be held up, so that any of the series may
when required be kept out of action. The cutter holders are arranged
without springs for returning them after each stroke, the progressive
motion of the stone effecting that object. A lining or bed of rubber or of
a fibrous or other suitable elastic material is interposed between the stone
and its carriage, and particularly between it and the part of the carriage,
which receives the endways strain of the cutting action. The slight
elasticity thus imparted to the stone improves the cutting action and saves
the cutters. The carriage is moved by a hydraulic cylinder, which in this
application presents important advantages over ordinary arrangements
of rack or screw, not being liable like them to derangement from sand
and dust, and admitting of a regulated strain being applied, and of the
movement accommodating itself to inequalities in the hardness of the
stone. The hydraulic cylinder is by preference fixed to the under side

page_text: of the carriage, the piston being stationary and fixed on a tubular rod,
by which the water enters and leaves the cylinder. The water may be
actuated by a single pump to give an intermittent movement, or by two
or more pumps to give a continuous one, but in either case a compen-
sating cylinder is provided to regulate the pressure of the water. Such
compensating cylinder contains a piston loaded by weights to the
intended pressure, and the piston rises when an increase of resistance
occurs until it uncovers ports in the side of the cylinder and allows
the surplus water to escape. Provision is also made for varying the
quantity of water pumped at each stroke and the consequent rate of the
progressive motion by working the pump through a link motion, like
that applied to steam engine valves, but with the rod from one end of
the link connected to a concentric pulley or part of the shaft, instead of
the rods from both ends being connected to eccentrics.
The Invention further comprises certain improved forms or arrange-
ments of cutters, in one of which each cutter has a horizontal surface
extending back from its point so as to lie and slide on the surface, which
it cuts, whereby it will be prevented from cutting too deeply into softer
parts of the stone. As viewed sideways the front of the cutter forms
nearly a right angle with the bottom, whereby a very strong cutting
edge or point is obtained. For finishing chisel-edged cutters are used,
being made angular at the edges, and so as to overlap cach other and
prevent ridges being left between them. With such cutters the entire
surface will be dressed at one operation.
SPECIFICATION in pursuance of the conditions of the Letters Patent,'
filed by the said Robert Girdwood in the Great Seal Patent Office
on the 16th September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
GIRDWOOD, of Edinburgh, in the County of Mid Lothian, North Britain,
Merchant, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of March, in the year of
our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give and,
grant unto me, the said Robert Girdwood, Her special licence that I, the

page_text: said Robert Girdwood, my executors, administrators, and assigns, or such
others as I, the said Robert Girdwood, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN MACHINERY OR APPA-
RATUS FOR CUTTING OR DRESSING STONE," upon the condition (amongst others)
that I, the said Robert Girdwood, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Robert Girdwood, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, that is to say :-
My said Invention relates in part to improvements in machinery or
apparatus of the kind described in the Specification of Letters Patent
granted to Andrew Mitchell, and dated 8th March 1869 (No. 704), and
in part to improvements also applicable to other kinds of machinery or
apparatus for cutting or dressing stone.
And in order that my said Invention and the manner of performing
the same may be properly understood, I have hereunto appended a
Sheet of explanatory Drawings to be herein-after referred to, and repre-
senting stone cutting or dressing apparatus as constructed with my
improvements. In the said Drawings the same reference numerals are
used to mark the same or like parts wherever they are repeated.
Figure 1 is a front elevation; Figure 2, a vertical section, as at right
angles to Figure 1; and Figure 3, an incomplete side elevation, whilst
the other Figures represent separate details, and are herein-after
specially referred to.
The machine is represented as arranged for operating with a trans-
verse row of tools or cutters, so as to simultaneously dress the entire
breadth of a block of stone, transversing longitudinally beneath them,

page_text: and its framing consists principally of two side standards 1 connected
by a sole plate 2 and tie rods 3. A strong transverse beam 4 is provided
and is made or fitted with a series of guides 5 for the front ends of the
several cutter holders 6, the latter being jointed to blocks 7 working
between the guides.
Figure 4 is an enlarged cross section of the guide beam 4, and
Figure 5 is an enlarged front view of one end, whilst a single tool
holder 6 is shown in each of these Figures, and a view of the under side
of one holder is shown below Figure 4. The guide beam 4 is formed
with journals 8 capable of turning in blocks 9 adjustable vertically in
the standards 1 by screws 10, and the beam is fixed by means of a
slotted segment and set screw 11 in the angular position required for
the desired kind of cutting action. The back end of each cutter holder 6
is jointed to a rod 12 swinging from a transverse horizontal shaft 13,
which is above the guide beam 4, but a little behind it, and for the
purpose of adjustment each rod 12 is made in two pieces with a screw
coupling and reversed screw threads. The hammer blocks 14 are fitted
with a screw adjustment upon levers 15, which swing from a second
higher transverse horizontal shaft 16, being loose on such shaft, but.
actuated by clutch bosses 17 fixed on the shaft. This shaft 16 has fixed.
on one end of it a lever 18 which is acted on by a cam 19 indicated by
dotted lines in Figure 2, and fixed on a shaft 20 made to revolve by any
suitable power, and a rocking motion is in consequence given to the
shaft 16, whereby the hammers 14 are lifted and let fall at intervals. In
some cases the hammer levers 15 are connected by jointed links 21 to
the pistons of air cylinders 22, the air in which is used as a spring to
intensify the force of the blows. The air cylinders 22 are fitted with
stop-cocks 23 to let out the air, and if this is done when a hammer is
raised and a cock then closed the hammer will be held up, so that any
of the series may when required be kept out of action. The air
cylinders 22 may be conveniently carried, as shown, by a cross beam 24
fixed between the standards 1. The cutter holders 6 are arranged
without springs for returning them after each stroke, the progressive
motion of the stone 25 effecting that object. The block of stone 25 to
be cut or dressed is held upon a plate or carriage 26 fitted with bars 27
at the sides to slide in grooved guides 28, which last are carried by a
frame 29 supported upon a hydraulic press 30. The hydraulic press 30
is for raising the stone into a position suitable for being acted upon by

page_text: the cutting tools, whatever its thickness may be, and the frame 29 is
guided vertically by tubular guides 31 fixed at its four corners and fitted
to slide on four vertical rods 32 fixed to the stationary framing. A
lining or bed of rubber, or of a fibrous or other suitable elastic material,
and indicated by a thickened line in Figure 2 is interposed between the
stone 25 and its carriage 26, and particularly between it and the part 33
of the carriage which receives the endways strain of the cutting action.
The slight elasticity thus imparted to the stone improves the cutting
action and saves the cutters. The carriage 25 is moved horizontally by
means of a hydraulic cylinder 34, which in this application presents
important advantages over ordinary arrangements of rack or screw, not
being liable, like them, to derangement from sand and dust, and
admitting of a regulated strain being applied, and of the movement
accommodating itself to inequalities in the hardness of the stone. The
hydraulic cylinder may be stationary, but I prefer to have it fixed, as
shewn, to the under side of the carriage 25, the piston 35 being stationary
and fixed on a tubular rod 36, by which the water enters and leaves
the cylinder 34, the outer ends of the rod being fixed to brackets 37
projecting out from the front and back of the frame 29. The water
may be actuated by a single pump 38, as shown to give an intermittent
movement, or by two or more pumps to give a continuous one, but in
either case a compensating cylinder 39 is provided to regulate the
pressure of the water. This compensating cylinder 39 has its bottom
in communication with the pipe 40, which leads the water from the
pump 38 to the hydraulic cylinder when moving the stone against the
cutters, and it contains a piston loaded by weights 41 to the intended
pressure. The piston rises when an increase of resistance occurs until
it uncovers ports in the side of the cylinder and allows the surplus water
to escape by a pipe 42 leading it back into the pump cistern. Provision
is also made for varying the quantity of water pumped at each stroke,
and the consequent rate of the progressive motion, by working the
pump 38 through a link motion, as will be best understood from the
detached side elevation, Figure 6. For working the pump there is on
the overhead revolving shaft 20 an eccentric 43, the rod 44 of which is
jointed to a slotted link 45, like that applied to steam engine valves, but
with the rod 46 from its other end connected to a concentric pulley
on or part of the shaft, instead of both shafts being connected to
eccentrics. The link 45 acts through a block on a pin on the pump
rod and is connected by a link 47 to a hand lever 48 arranged in con-

page_text: nection with a catch plate 49, by means of which hand lever the
position of the link 45, and consequent length of stroke of the pump
is regulated. The ends of the fixed tubular piston rod 36 are connected
by flexible tubes 50 with pipes 40 and 51 leading to and from the pump;
these pipes communicating with the pump by means of a four-way
cock 52, and it is by shifting the lever 53 of this cock that the carriage 26
is made to move backwards or forwards.
My Invention further comprises certain improved forms or arrange-
ments of cutters, in one of which, as seen in Figure 7, the cutter being
shown in its holder 6, each cutter 54 has a horizontal surface extending.
back from its point, so as to lie and slide on the surface which it cuts,
whereby it will be prevented from cutting too deeply into softer parts
of the stone. As viewed sideways the front of the cutter forms nearly
a right angle with the bottom, whereby a very strong cutting edge or
point is obtained.
For finishing, chisel-edged cutters are used, such as are shown in plan
and side view in Figure 8, being made angular at the edges, and so as
to overlap each other and prevent ridges being left between them. With
such cutters the entire surface will be dressed at one operation. It is
however to be understood, of course, that any suitable form of cutter
may be used, and plain chisel-shaped ones are shown as applied in
Figures 1, 2, 4, 5. The cutters 54 are held in their holder 6 by means
of a lever 55 formed with a T end, which enters an indent or notch
formed in the under side of the cutters, the arrangement being such as
will be easily understood from the Drawing.
Having thus particularly described my said Invention, and the manner
in which the same is to be performed, I have to state that I do not
restrict myself to the precise details herein described or delineated, but
that what I believe to be novel and original, and claim as the Invention
secured to me by the herein-before in part recited Letters Patent is,―
1. The improved construction and arrangement of the guide beam 4.
2. The improved mode of carrying and guiding the tool holders.
3. The improved mode of arranging the hammers and their actuating
parts.
4. The improved adaptation of the air cylinders to the hammers.
5. The bedding of the stone upon and against a lining of rubber or
other suitable clastic material.

page_text: ROBERT GIRDWOOD. (L.S.)