IMPROVEMENTS IN MACHINERY FOR CUTTING COAL, STONE, OR OTHER MINERALS
Year: 1868

page_text: LETTERS PATENT to Samuel Firth, of Leeds, in the County of
York, Merchant, for the Invention of "IMPROVEMENTS IN MACHINERY
FOR CUTTING COAL, STONE, OR OTHER MINERALS."
Sealed the 31st July 1868, and dated the 22nd February 1868.
PROVISIONAL SPECIFICATION left by the said Samuel Firth at the
Office of the Commissioners of Patents, with his Petition, on the
22nd February 1868.
I, SAMUEL FIRTH, of Leeds, in the County of York, Merchant, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
MACHINERY FOR CUTTING COAL, STONE, OR OTHER MINERALS," to be as
follows:-
In the machinery now used for cutting coal, stone, or other minerals,
when it is desirable to cut to a greater depth than can be effected by
one pick, it is the practice to employ in succession additional picks
similar in shape to the first, with the exception that the second pick
both in shaft and point is longer than the first, the third longer than
the second, and so on. A serious inconvenience involving considerable

page_text: increase in the cost of working results from this, since the swing or
back stroke of the pick renders necessary an increase in the breadth
of the roadway or level proportionate to the increase in the length of
the pick. The object of my Invention is to get rid of this difficulty
by so altering the shape of the pick as to effect a deeper cut by bringing
a second pick or any number of additional picks in succession more
and more forward into the groove as the depth of cutting is increased,
so that the swing or back stroke of the succeeding picks shall be more
in the groove, and less in the roadway or level. The present practice
is to form the pick with a straight pick shaft at right angles to the
point; this form of pick I use for the first pick only. The second
pick I form either of a straight shaft at an obtuse angle to the point
or of a shaft with an elbow or bend forward in it, so as in either
case to bring the pick in advance of the machinery, and nearer the
mineral to be cut than heretofore. The same effect may be produced
by substituting a pick of a totally new form, that is, in the form of
a segment of a circle or other suitable curve. The third pick will be
similar to the second, but with this exception, if the pick be formed
of a straight shaft, having an obtuse angle to the point, the obtuseness
of the angle must be increased. If the pick be formed of a shaft with
an elbow or bend forward, the length of the elbow or bend must be
increased, and if the pick be made in the form of a segment of a
circle or other curve, the length of a segment must be increased.
The fourth pick will vary from the third exactly as the third varies
from the second and by similar variations. Any number of picks may
be used in succession, each one cutting deeper into the coal, stone, or
mineral than the preceding one. Each succeeding pick would thus
have a swing or back stroke more within the groove and less in the
roadway or level than its predecessor, consequently the breadth of
roadway or level required for the working of a single pick would be
sufficient for any number of successive picks.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of February, in the
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs, and successors,
give and grant unto me, the said Samuel Firth, Her special licence,
that I, the said Samuel Firth, my executors, administrators, and
assigns, or such others as I, the said Samuel Firth, 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 FOR
CUTTING COAL, STONE, OR OTHER MINERALS," upon the condition (amongst
others) that I, the said Samuel Firth, 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 Samuel Firth, 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, that is to say :-
In the machinery now used for cutting coal, stone, or other minerals
when it is desired to cut to a greater depth than can be effected by
one pick, it is the practice to employ in succession additional pick
similar in shape to the first, with the exception that the second picks
both in shaft and point is longer than the first, the third longer than
the second, and so on; and since in order to give to the first pick
sufficient swing to obtain an effective blow it is necessary that at the
end of the back stroke the stem of the pick should incline away from
the face of the coal or mineral, it results that if for deepening the
groove cut by the first pick a pick with simply a longer stem be
substituted for the pick first used, the pick will at the end of the back
stroke project further back away from the face of the coal and into
the roadway or level. A serious inconvenience involving considerable
increase in the cost of working arises from this, since the swing or

page_text: back stroke of the longer pick renders necessary an increase in the
breadth of the roadway or level. Now the object of my Invention is
to get rid of this difficulty, which I effect by so altering the shape of
the picks which are to be used subsequently to the first pick, that
the swing or stroke of such picks shall be more in the groove and less
in the roadway or level. For this purpose I so form the stems of the
two, three, or more picks which are to be used in succession with the
machine, that whilst the ends of the stems may each in turn be received
into the socket or holder on the axis of the machine (which socket is
always brought back into the same position at the end of each backward
stroke), the outer ends of the succeeding picks shall (at the end of
the back stroke) project but little if at all further back into the roadway
than the first pick, and by preference I form them not to project
quite so far back, the main stem of the picks which are to be used
after the first pick being for this purpose curved or bent according
to my Invention at an angle to the end portion of the stem which
fits into the socket or holder on the axis of the machine.
In the Drawings hereunto annexed Figure 1 shews a diagram Drawing
of three picks, such as have heretofore been used in succession for
cutting a groove into the coal or mineral. To commence cutting the
groove the end a of the stem of the pick No. 1 is first fixed in the
socket or holder on the axis of the cutting machine, and a groove is
cut with this pick, the axis of the machine being for this purpose
usually caused to oscillate approximately one-fourth of a revolution to
give each stroke or blow, whilst at the same time the cutting machine
is caused to travel slowly along the face of the coal or mineral into
which the groove is to be cut. When a groove has thus been cut
pick No. 1 has been removed from the socket or holder, and pick No. 2
substituted for it, and when the groove has been deepened with pick
No. 2 it has been again subsequently deepened with pick No. 3, and
so on for any number of picks desired. Figure 2 is a diagram view
shewing the position of each pick at the end of the back stroke, from
which it will at once be seen that a much greater breadth of roadway
is required when using the longer picks than when using the shorter
picks, thus materially limiting the extent to which the number of
successive picks and consequently the size of the pick can be increased.
At Figure 3 is shewn a set of three picks constructed according to
my Invention; this is a series such as I commonly employ, but a greater

page_text: number of picks may be successively used. The main stems of the
second and third picks of this set are curved at an angle to the ends a
of the stems, which fit in the socket or holder of the reciprocating axis
of the cutting machine. Figure 4 shews all of the three cutters in
the position they assume at the end of the back stroke; from this
view it will be clearly seen that no broader roadway is required
when using the longer picks than when using the shorter picks.
In place of the stems of the picks being curved, as shown at
Figure 3, they might be formed with a right angle bend, as shewn
at Figure 5, or the stems might be straight or nearly so, as shewn
at Figure 6, and be merely at an angle to the portion a of the stem
which is received in the socket or holder of the axis of the
machine. Or the stems of the picks might be of other forms so long
as the stems of the successive picks be so made that the swing or stroke
of the succeeding picks shall be more in the groove and less in the
roadway or level than the swing or stroke of the first pick, so that
whenever requisite any number of succeeding picks can be used cutting
any required additional depth in the same working space, or less than
that required for the first pick. This saving in the amount of working
space required has several advantages, the most important being the
great saving of expense in making the roadway or level before the
coal-cutting machine can be set to work.
In witness whereof, I, the said Samuel Firth, have hereunto set
my hand and seal, this Twentieth day of August, in the year
of our Lord One thousand eight hundred and sixty-eight.
Signed, sealed, and delivered by
the said Samuel Firth in the
presence of
THOMAS TURNER,
SAMUEL FIRTH. (L.S.)
Solicitor,
Leeds.