IMPROVE- MENTS IN MACHINERY OR APPARATUS FOR PERFORATING. ROCKS TO FACILITATE THE FORMATION OF TUNNELS, GALLERIES OF MINES, AND FOR OTHER SIMILAR PURPOSES
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by James Stevenson at the Office of
the Commissioners of Patents, with his Petition, on the 3rd March
1866. A communication from abroad by Theophilus Berrens, of the
"Town of Tarbes, in the Empire of France, Railway Engineer.
1, JAMES STEVENSON, of 19, Salisbury Street, Strand, in the County of
Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN MACHINERY OR APPARATUS FOR PERFORATING. ROCKS TO FACILITATE THE
FORMATION OF TUNNELS, GALLERIES OF MINES, AND FOR OTHER SIMILAR PURPOSES,"
(a communication to me from abroad by Theophilus Berrens, of the Town of.
Tarbes, in the Empire of France, Railway Engineer,) to be as follows:-
The object of my Invention is to increase the progress of the work in
cutting through or excavating hard rocks by putting ten, fifteen, twenty, or
more men to the work where no more than one or two could work together
according to the method at present in use.
The perforating apparatus constructed according to this Invention consists
of a sheet iron cylinder of about four feet and one-half in diameter and three
feet in length, supported by a long round iron central bar or shaft, on which
it is securely held by means of a strong cross piece; the sheet iron cylinder is.
furnished at its outer end with several sets of boring tools of various shapes..
The central shaft is carried over several grooved pulleys, over which it can
slide; at its outer end it is fitted with a boring tool, while its opposite inner
end has a toothed wheel keyed upon it, which gears into and is worked by an
endless screw; besides, the central shaft runs in a bearing or bearings sup-
ported near the pulleys by a long wooden frame which is laid down in the

page_text: tunnel. Another long upper wooden frame is attached to or connected with
the iron cross piece carrying the shaft; the latter wooden frame is furnished
with cross pieces similar to the steps of a ladder, supported by two or three
pairs of wheels travelling on rails laid down at the bottom of the tunnel.
In working a perforating apparatus constructed according to this Invention
several men are seated on boards with their back turned towards the working
tools, one man being seated between every two steps of the ladder. Each
workman holding one of these steps pushes forward, and thus draws back the
ladder and at the same time the cylinder in the manner usual in rowing boats.
By repeating this motion the boring tools will be made to enter the rock and
form a circular or annular channel. At each blow a slight motion of the
endless screw causes the toothed wheel to turn round and describe a limited
arc of circle, by means of which the position of the boring tools is changed,
and in this manner small particles will be detached from the rock. A small
stream of water is led into the channel as it is perforated, to assist in the
progress of the work. As soon as the depth of the channel has become equal
or nearly equal to the length of the perforating cylinder the latter is removed,
and gunpowder haxing been introduced into the circular or annular channel
or ditch it is exploded and the particles of rock detached are carried away.