IMPROVEMENTS IN MACHINERY FOR CUTTING AND DRESSING STONE, MARBLE, AND SIMILAR MATERIALS
Year: 1856

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street, in
the City of London, Patent Agent, for the Invention of "IMPROVEMENTS
IN MACHINERY FOR CUTTING AND DRESSING STONE, MARBLE, AND SIMILAR
MATERIALS."-A communication.
PROVISIONAL SPECIFICATION left by the said Richard Archibald
Brooman at the Office of the Commissioners of Patents, with his
Petition, on the 8th November 1856.
I, RICHARD ABCHIBALD BROOMAN, of 166, Fleet Street, in the City o
London, Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN MACHINERY FOR CUTTING AND DRESSING STONE, MARBLE,
AND SIMILAR MATERIALS," (communicated to me by a foreigner residing abroad;)
to be as follows:-
This Invention ralates to stone cutting and dressing machinery, the principle
being to imitate hand cutting as nearly as possible. The distinctive features.
of the Invention lie in the manner of working the cutting chisels. The
stone is carried along in a horizontal direction upon a moveable platform,
while the chisels are made to act upon its upper surface in an inclined
direction, and opposite to that of the feed; these chisels are supported in
guides or sliding stocks formed in the lower cross rail of the frame. Each guide
stock is connected to a toggle lever, the upper end of which is fastened to the
upper cross rail of the frame, and it is by acting upon the centre joint of the
toggles, whereby they are made to vibrate, that motion is given to the chisels.

page_text: To accomplish this, two sets of cams revolve upon two shafts, one shaft being
on one side of and near to the middle joint of the toggle, while the other is on
the opposite side in like position. These shafts are coupled together by cog
gearing, and the cams are so set, that when one cam strikes a toggle, the cam
on the shaft opposite will be out of the way of that cam, thus allowing the
toggle to vibrate. As the first cam leaves, the opposite one comes round, and
striking the toggle, forces it back. Thus the chisels are made to vibrate in a
series of short, powerful, and rapid shocks; the points or edges being driven
into the stone, chips it off, in a manner very similar to the action of hand
cutting. There are provisions for raising and lowering the chisels and other
adjustable parts for the feed, angular direction, depth of cut, &c.
The Invention may be applied to marble, and other materials similar
to stone.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal Patent Office
on the 5th May 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing dato the Eighth day of November, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
tho said Richard Archibald Brooman, Her special licence that I, the said
Richard Archibald Brooman, my executors, administrators, and assigns, or
such others as I, the said Richard Archibald Brooman, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during tho 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 FOR CUTTING AND DRESSING STONE,
MARBLE, AND SIMILAR MATERIALS," (communicated to me by a foreigner
residing abroad,) upon the condition (amongst others) that I, the said Richard
Archibald Brooman, my executors or administrators, by an instrument in.
writing under my, or their, or ono of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner

page_text: 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 tho
date of the said Letters Patent.
NOW KNOW YE, that I, the said Richard Archibald Brooman, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by
the following statement thereof, reference being had to the Drawings hereunto
annexed, that is to say :-
This Invention relates to stone cutting and dressing machinery, the
object being to imitate hard cutting as nearly as possible.
The distinctive
features of this Invention lic in the manner of working the cutting chisels.
The stone is carried along in a horizontal direction upon a moveable platform,
while the chisels are made to act upon its upper surface in an inclined
direction, and opposite to that of the feed; these chisels are supported in
guides or sliding stocks formed in the lower cross rail of the frame. Each
guide stock is connected to a toggle lever, the upper end of which is fastened
to the upper cross rail of the frame, and it is by acting upon the centre joint
of the toggles, whereby they are made to vibrate, that motion is given to the
chisels. To accomplish this, two sets of cams revolve upon two shafts, one
shaft being on one side of and near to the middle joint of the toggle, while the
other is on the opposite side in like position. These shafts are coupled
together by cog gearing, and the cams are so set, that when one cam strikes a
toggle, the cam on the shaft opposite will be out of the way of that cam, thus
allowing the toggle to vibrate. As the first cam leaves, the opposite one
comes round, and striking the toggle, forces it back. Thus the chisels are
made to vibrate in a series of short, powerful, and rapid shocks; their points or
edges being driven into the stone, chip it off, in a manner very similar to the
action of cutting.
The stone to be cut is placed upon a travelling bed, which moves in a
horizontal direction, an end view of the same being shewn in Figure 1, and a
side view in Figure 2, at A, with the stone in position upon it at B. This bed
is moved along by a rack and pinion, with means for varying the speed
suitable for the various kinds of stone, comprising well-known mechanical
devices. The stone is cut and dressed by means of chisels and cutters set on
an angle to the surface operated upon. These chisels, together with the
toggles and cams for working them, are held in a strong carriage placed in the
frame C, the lower ends of which frame are secured to the outside of
the foundation plate by strong bolts c. The carriage is represented in a front
view in Fig. 1 at D, and in section in Fig. 2. It is held in the frame C by

page_text: means of guide plates a, which embrace the upright, so that the carriage may
be moved up and down by a regulating screw, whereby the chisels may be
brought within proper distance of the stone. This carriage is moved by the
screw (6), placed in the cross head of the frame. In the lower cross rail of the
carriage metal boxes are secured, in which play the chisel stocks or handles c,
tho various shaped chisels used being adapted to be removed and introduced
as required, the chisel shank entering a hole in the stock, and being held there
by a pinch screw c', as shown. In the Drawings but two chisel stocks with
their working toggles are represented; a much larger number, however, are
designed to be used in machines of great size, the principle of operation being
the same for all numbers.
In the centre of the carriage are placed the toggle levers, before mentioned,
and as shown at d the upper ends of these are attached to the upper cross
head of the carriage D, while the lower end of each is attached to one of the
cutter stocks c. Upon the same pin, by which the two centro ends of the
toggle links are held, is a friction roller e, upon which the cams strike. The
cams, of which there are two to each toggle, viz, one to act upon the front
and the other upon the back, are secured to two shafts, one on either side of
the frame, directly opposito to each other, and in line with the centre joint of
the toggles; the front shaft is at i and the back at i'. Each shaft plays in
journal boxes affixed to the carriage D, so that the chisels, toggles, shafts, and
cams all move together with the carriage. The shafts are connected together
by gear wheels (traced in dotted lines in Figure 2), so that they revolvo
together with a positive motion. The cams are seen at k and k', and are
strong arms with rounded ends, fitted to strike fairly upon the rollers e as they
revolvo. The cam on the front shaft stands at right angles to k upon the
back shaft, as shewn in Figure 2, and they are capable also of being set by set
screws at different positions upon their shafts, but in whatever position one
cam may be placed as respects the others on the same shaft, the opposite one
on the other shaft must stand at a right angle to it. The object for shifting
the cams, is, that they may be so set when commencing the work of cutting on
the stone, i. c., in roughing it down, that the chisels may be driven down in
successive order across the surface; but in finishing, it is required that the
cams on each shaft be adjusted to strike tho toggles in unison, because a long-
bladed tool is then put in, which gives the finishing cut across the entire stone
at one blow. The frame C stands at an angle to the surface of the stone, and
is supported by standards E, the top ends of which are slotted, through which
a pinch nut connected with the frame takes hold, and as the chisels cut some
kinds of stone better at one angle than another, adjustment in this respect is

page_text: thus provided for. Instead of these standards, screws, or rack and pinion upon
a quadrant, may be substituted. The operation is as follows:-Rapid motion
being given to the shafts i and i', the cams kand k¹ will alternately strike
upon opposite sides of the toggle, and thus deflect it back and forth. As the
upper end is attached firmly to the cross bream, the lower one must needs
yield, and the stock c and chisel attached to it be set in vibration. When the
toggle is bent, as shewn by the action of cam k, Figure 2, its chisel is lifted
slightly from the surface of the stone which is being fed along all the while
with a constant and regular though slow motion. As soon as the point of k
has passed the centre of the friction wheel e', the cam k¹ approaches and strikes
it from the other side, as shewn in the duplicate line in Figure 2, straightening
the toggle, and thereby driving down the chisels with great force upon the
stone; the cam continues on and bends the toggle in the opposite direction,
thus lifting again the cutter ready to receive the next impulse from the cam k,
and so on. When the stone has been thus acted upon from end to end the
frame c may be raised a little towards a vertical position, by which the cutters
will be lifted quite clear, and the stone then run back to the place of beginning,
if it requires further reduction or finishing. The chisels may then be changed
for those of other forms as may be wanted. To start again, bring the frame c
to the proper angle, then by turning the screw b send the carriage D down, so
as to bring the edges of the chisels in contact with the stone, when the work
will go on as before. Mouldings, grooves, &c. may be cut by introducing the
proper shaped chisels for the purpose. To some extent the driving of the
toggles from side to side by means of cranks would be the equivalent of the
cams, but the ultimate action of the chisels essential in roughing down could
not be thereby so well attained, together with the ability to place one con-
tinuous tool in the cutter stocks for finishing.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I claim the method of
driving the chisels in cutting too!s by means of toggle levers, caused to vibrate
and act in the manner herein-before set forth.
In witness whereof, I, the said Richard Archibald Brooman, have
hereunto set my hand and seal, this Fifth day of May, One thousand
eight hundred and fifty-seven.