AN IMPROVED APPARATUS FOR CUTTING OR DRESSING STONE, APPLICABLE ALSO TO OTHER PURPOSES WHERE RAPID BLOWs ARE REQUIRED
Year: 1869

page_text: LETTERS PATENT to Léon Pochet, of Vendôme (Loir et Cher), France,
Engineer, for the Invention of "AN IMPROVED APPARATUS FOR CUTTING
OR DRESSING STONE, APPLICABLE ALSO TO OTHER PURPOSES WHERE RAPID BLOWs
ARE REQUIRED."
Sealed the 24th May 1870, and dated the 27th November 1869.
PROVISIONAL SPECIFICATION left by the said leon Pochet at the
Office of the Commissioners of Patents, with his Petition, on the
27th November 1869.
I, LÉON POCHET, of Vendôme (Loir et Cher), France, Engineer, do
hereby declare the nature of the said Invention for "AN IMPROVED
APPARATUS FOR CUTTING OR DRESSING STONE, APPLICABLE ALSO TO OTHER PURPOSES
WHERE RAPID BLOWS ARE REQUIRED," to be as follows:-
My Invention relates to dressing stone by machinery, and consists of
an apparatus worked either by air or steam and suspended by chains
from pullies affixed to a tripod or other convenient means of transport.
[Price 8d.]

page_text: The stone cutting machine consists of a piston working in a cylinder,
the rod of the said piston carrying at its outer extremity a tool holder in
which the chisel for operating upon the stone is fixed. The tool
holder is connected by a tie rod to a spindle working in bearings parallel
to the course of the piston, the said spindle being connected at the opposite
end to a lever to which is jointed the spindle of the slide valve in such
manner that the action of the piston regulates the motion of the valve as
required. This valve consists of a single plate of metal having three
ports, the said ports communicating with the steam and exhaust ports of
the cylinder as usual, and above the said valve and supported by it is a
second or regulating valve having'two ports, one for the admission and one
for the exhaust steam. The upper valve is pressed on to the lower one by
means of springs and moves with it until stopped at one end of its stroke
by a tappet and at the other by a cam which according as its greatest or
least excentricity is presented to the said valve regulates the admission
of steam, and therefore the strength of the stroke of the
spring is provided on the spindle in communication with the
and valve spindle lever to cushion the strokes of the piston.
is caused to act on the piston during one half of its stroke or there-
abouts at which point the admission port is closed and the steam enters
at the opposite port, the admission and exhaust being regulated so
that as soon as the tool has struck the stone the steam is reversed and
the piston returns to its former position ready for a second stroke and
so on.
chisel.
A
tool holder
The steam
For small machines one valve only may be used, in which case the
steam is always reversed at half stroke. The stone is placed within the
tripod or other support, and the workman holding the apparatus by means
of two handles provided for the purpose presents the chisel to the stone at
those parts that require dressing, the force of the stroke being to a certain
extent regulated by the pressure applied by the operator. The steam is
led from the boiler to the apparatus by means of an india-rubber tube, the
cock by which it enters being regulated by turning one of the handles of
the apparatus, and the fixed position thereof being maintained by a catch
lever taking into a ratchet wheel on the axis of the said handle. The edges
of the stone may be dressed either by an ordinary chisel or by a jointed
chisel. The limit of the course of the chisels is determined by straight
edges joined together by any suitable means, the vertical straight edge
regulating the horizontal dress, and vice versa.

page_text: This system of dressing may be employed also for rough grinding
stones, for dressing millstones, drilling holes iu mines, cutting out stone
in quarries, and in fact to all purposes where rapid blows directed by
hand are available.
The apparatus may also if desired be placed upon a frame and moved
therein either in a vertical or horizontal direction, the said frame being
placed on wheels to facilitate transport.
SPECIFICATION in pursuance of the conditions of the Letters Patent,.
filed by the said Léon Pochet in the Great Seal Patent Office
on the 26th May 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Leon
POCHET, of Vendôme (Loir et Cher), France, Engineer, send greeting.
WHEREAS Her most excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of November, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Leon Pochet, Her special licence that
I, the said Leon Pochet, my executors, administrators, and assigns,
or such others as I, the said Leon Pochet, 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 the terin 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 "AN IMPROVED APPARATUS
FOR CUTTING OR DRESSING STONE, APPLICABLE ALSO TO OTHER PURPOSES WHERE
RAPID BLOWS ABE REQUIRED," upon the condition (amongst others) that I,
the said Leon Pochet, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Leon Pochet, 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

page_text: the following statement thereof, reference being had to the accom-
panying Sheet of Drawings (that is to say):―
My Invention relates to dressing stone by machinery, and consists of
an apparatus containing a striking or picking tool and weighing from
30 to 100 kilogrammes or more according to the force of the blows
desired to be struck, the said tool being worked either by steam or
compressed air and suspended in any suitable manner so that the
workman can easily direct it upon the stone to be cut without using
his own muscular power either to guide or support the machine.
The accompanying Sheet of Drawings represents a stone dressing
machine weighing 68 kilogrammes, a piston P works in a cylinder A, B,
and has at one end a tool holder e, a metal bar i, serving permanently
to connect the piston rod with a parallel rod c which slides in two
sockets d, d. A crank 6 jointed at k to the rod c works a lever s
oscillating on a fixed joint o and through the rod a actuates the valve T.
This valve therefore works parallel to the piston P with a speed reduced
as required, the piston itself regulating its movement. The valve T
carries a second valve t which it draws backward and forward in its
movements the top valve being pressed to the bottom one by springs,
the expansion valve t is limited in its action to the right by the tappet m
which strikes against the side of the valve box, and to the left by the
elliptical cam n regulated from the exterior by the handle p. When the
valvet has struck against either of its stops, the main valve continues its
travel alone until its return stroke.
The strokes of these valves produces the following results :-
First Period. As the piston P leaves its norinal position, seen m,
Fig. 1, there is exhaust at B, and full pressure at A, the full pressure
acts during half the stroke of the piston, that is about eight centimetres
in the machine, shewn in Fig. 1; at the middle of the stroke the
induction ceases in A and commences in B, the exhaust ceases in B
and commences in A. In this first period the speed of the piston
commences at zero and attains its maximum speed. Thus the middle
of the free stroke of the piston always corresponds with its greatest
speed.
Second Period.-As the piston leaves the middle of the stroke the
steam retards the speed instead of increasing it and towards the end of the
stroke the piston stops. But if the tool has struck the stone before the

page_text: end of its stroke the piston returns by reason of the pressure of the
steam in B, so that whenever the pick of the tool takes place the piston
returns. This second period may be called the useful period of the
stroke.
Third Period. The speed of the piston on its return increases as long
as the pressure exists in B and the exhaust in A continues till the piston
has passed the centre of its stroke.
Fourth Period. At this moment the valves are reversed, the exhaust
is at B, and the induction at A; by reason of the reaction of the steam
at A the piston slackens speed and eventually stops at the point from
which it started, to proceed again as before. Thus from the relative
positions of the ribs l, m, of the expansion valve with the ports L, M, of
the valve there can be no pressure at A when there is exhaust at B, and
vice versa. In the forward stroke reversal always takes place in the
middle of the stroke, in the back stroke either at 8, 7, 6, 5, 4, 3, 2, or 1
centimetre before the return of the piston to its normal position
according to the set of the elliptical cam n, which is regulated according
to the force of the blows required by presenting a diameter to the
valve inverse to the force. In Fig. 1 reversal takes place at 6
centimetres.
In certain cases especially for small machines the two valves may be
reduced to one when the reversal always takes place in the middle
of the cylinder, the quantity of steam alone regulating the force of the
stroke. It will be understood that the sector or elliptical cam which
transmits the alternate rectilinear motion to the valve spindle may be
placed in front of the machine instead of at the back.
The machine is shewn ready for use in a workshop in Figs. 4 and 5.
It is fixed in bearings a¹, a¹, placed rather below its centre of gravity,
the axle being free to turn in the said bearings in the arms of a
fork b¹, b¹. At the right is seen an iron quadrant c¹, 1, shewn in
elevation Fig. 5. The right arm of the fork has a screw d, and when
the machine turns upon its axis a¹ it draws with it the quadrant c' in
which is a curved groove enclosing the head of the screw d¹ so that the
machine can be fixed in any position by the handle e¹ and remains at
any suitable angle. The fork 6, 61, forms a bearing for the vertical
shaft g (which is but a prolongation of the bar f¹) and turns freely
thereupon. It can therefore be fixed in any horizontal position by a
second handle h' tightening on the semicircular quadrant k¹. Thus the

page_text: machine can be fixed in any desired position on its horizontal and
vertical axes.
The bar passes through a socket m¹ carried upon two
wheels, and can slide longitudinally therein and be placed
obliquely but it has no play in a perpendicular direction. The
wheels r,, run upon a horizontal rail t' and wheels p¹, p¹, one fixed to
the bar the other to the socket m¹ enable the inachine to be raised
and lowered by a differential pulley or other suitable means; thus when
the machine is in position it can,-1 be set at the required angle by
means of the two screws e¹ and h¹; 2, it can be raised to the horizontal
plane at which it is required to dress the stone by actuating the
wheels ; and 3, it can be shifted horizontally by rolling it along the
rail t. The rail t¹ forms part of a truck composed of two triangular
uprights n', n, joined together below by iron stays, the truck when in
position resting on two small wheels s¹, s¹. When it is desired to remove
it to another position two bars r¹ having their fulcra at o' are brought to
bear upon the axles of two wheels R, R, by which means the truck is raised
off the ground, the bars are held in the hooks %, and the truck is only
supported by the large wheels R, R. During the process of cutting the
stone the bar f¹ is inclined to the line m', y', (Fig. 5,) which enables the
workman to put more force upon the directing handles. Or the appa-
atus may be suspended from a tripod 5 or 6 yards high by a differential
pulley or otherwise balanced by a counter weight, it is thus completely
free. The operator simply holds it by the handles N, N, of wood or
elastic material and directs the tool against the required spot on the
stone. The angle of the machine is regulated by the length of the
chain by which it is attached to the pulley. It is necessary that the
omparative weight of the cylinder to the piston should be at least 10
to so as to lessen the vibrations of the handles. The blows of the tool
on the stone are regulated also by the pressure brought to bear on the
machine by the operator. The steam enters by an india-rubber tube
attached to the projection V by a cock which is opened and closed by
turning the left handle N, the motion being transmitted to the cock by
a lever and crank (Figs. 2 and 3), the handle can be retained in any
position by a spring pawl a fixed in any one of the teeth of the ratchet
wheel y.
The handle p of the cam can also be fixed in any position by
a lever turning on a toothed disc as in a te'egraphic apparatus. The
resistances of the piston are decreased in its forward stroke by the spiral
spring placed upon the rod c, and the fixed bearing d. In its return
the piston P draws back the valves and compresses the spring
The

page_text: dressing is accomplished with the aid of horizontal zones placed one above
another. The tools I employ are similar to those used for hand work,
especially chisels with 4, 9, or 16 teeth.
The chipping of the edges is performed by an ordinary chisel or by the
jointed chisel having a spring h represented in Fig. 6 the stone being
dressed horizontally for this
purpose. The chisel is guided by right
angled straightedges properly arranged and fixed upon the stone by two
screws at each end. The vertical straightedge is the limit of the
horizontal dress and the horizontal straightedge of the vertical dress;
when one stone is dressed the work man proceeds to another either by
advancing the truck (Fig. 5), or by moving successively the feet of the
tripod.
The machine may be worked either by steam or compressed air; for
compressed air, a motor, an air pump, a reservoir, and a main pipe and
india-rubber branch pipes are necessary; for steam a boiler, a main pipe
and metallic branch pipes are required and affixed to each machine an
india-rubber tube a yard or two long. This machine may be used according
to its size either for rough dressing, dressing, or smoothing stone with
slight variations in its dimensions, it can also be used for dressing mill-
stones, drilling holes in mines, getting stone in quarries, and for any other
purpose where rapid blows directed by hand are required.
When it is required to drill holes in mines it is placed upon a carriage
by its bearings a¹ and the ordinary tool holder is changed for a rotary
tool holder represented in section Fig. 7 and in front view Fig. 8. A
nut B¹ is screwed upon the piston rod A¹ and fixed by set screws; the
said nut carries a ratchet wheel D and a tool holder C screwed one upon
the other and turning together around the nut B₁; a ring E turns around
the arrangement D, C, and carries a bearing F, F, receiving in a socket
the rotary shaft of a ratchet G, G. The bearing also sustains a helicoidal
bar H, H, (Fig. 9,) fixed upon the cylinder of the machine. When this
piston makes its forward stroke this bearing slides along the helicoida
bar H, the ratchet G turns in the direction of the arrow 1, the ring E slides
upon its axis, and the tool does not change its position, but in returning
the ratchet G turns in the direction of the arrow 2 and draws the wheel I)
and the tool with it, also causing the arrangement C, D, to make
about one-fifth of a rotation at each stroke, this movement is necessary
to prevent the spindle from clogging in the hole. At the ordinary pressure

page_text: of 5 atmospheres it is desirable that the cylinder should be at least 9 centi-
metres in diameter.
Having thus described the nature and particulars of my. Invention, I
claim the improved apparatus for cutting or dressing stone, drilling holes
in mines, and for other purposes where rapid blows are required. as all
such improvements are herein described and illustrated in the accompanying
Drawings.
In witness whereof, I, the said Leon Pochet, have hereunto set
my hand and seal, this Twentieth day of May, in the year of our
Lord One thousand eight hundred and seventy.
Witness,
CH. ARMENGAUD,
Civil Engineer,
Boulevard de Strasbourg, 25,
Paris.
L. POCHET. (L.S.)