An Improved Tool for Drilling Out or Removing Non-exploded Cartridges or Petards from Mines, Quarries, or the like.
Year: 1893

page_text: Date of Application, 9th Jan., 1893-Accepted, 11th Feb., 1893
COMPLETE SPECIFICATION.
An Improved Tool for Drilling Out or Removing Non-exploded
Cartridges or Petards from Mines, Quarries, or the like.
A communication from FRANZ KÜHN, of Lehesten, Thüringen, in the Empire of
Germany, Owner of Slate-quarries.
i I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I. Mech. E., and Chartered Patent Agent, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The removal of non-exploded cartridges or petards from mines and quarries is an.
operation apt seriously to endanger the life or health of the men employed in it,
and this circumstance has caused a number of warnings to be issued and of special
rules to be set down for their protection by the respective authorities. For example:
boring for non-exploded cartridges with ordinary tools is prohibited, and rightlyi
so; yet experience shows that there is frequently a tacit understanding in the
gang of workmen employed to disobey this prescription, made for their safety,
simply because they consider its observance as too long and tedious. For this
reason the removal of cartridges which have once failed to explode is in many
cases dispensed with altogether, a fresh cartridge or petard being simply placed in'
the vicinity of the non-exploded one. This expedient however also has proved less
reliable than had been expected as it is by no means certain that the explosion of...
the new cartridge will in all cases cause the old one to explode too....
The tool forming the subject of this invention has therefore been devised as a
means of removing non-exploded cartridges or petards with facility and without.
danger, and it consists of a twist drill or auger offering three features which distinguish
it from similar tools hitherto used for boring holes in metal. The first feature is
the peculiar arrangement of the cutting edges as illustrated by the accompanying
drawings. Instead of forming an angle having its apex turned outwardly as they
do in ordinary twist-drills, the blades here start from the centre and form an
angle the sides of which open outwardly, while its apex is directed inwards.
This is illustrated in Fig. 1 of the accompanying drawings in which a are the
cutting edges so arranged as to avoid forming a point which in meeting and suddenly
perforating a dynamite cartridge might bring about an explosion. With cutting
edges arranged as shown no puncturing takes place at all but only a cutting or
scraping action which is free from any danger even if performed by inexperienced
hands, or without precaution.
The next feature is that the stem 6 of the tool is graduated for a purpose
presently to be set forth; and the third feature is the employment in the manu-
facture of the tool or bronze or any other metal possessing the property of giving
off no sparks when brought into frictional contact with stone or ore, which is of
great importance considering the special purpose for which the tool is intended.
The operation of the tool is as follows,-
In tamping blast-holes the depth of the tamping must be exactly determined and
maintained. If any one of the cartridges should fail to act the tool is bored into
the tamping and in so doing causes the material, which the cutting edges scrape off
to travel to the surface along the convolutions of the screw or twist of the drill.
In the case of gunpowder petards which have been "drowned," the gunpowder
also is brought up in this manner, but not in the case of charges other than of gun-
powder. The depth of boring is controlled or may be ascertained by means of the
divisions or graduations of the stem which should be carefully observed especially
where dynamite or other similar explosives which are not impaired by water are

page_text: used in blasting. Upon the removal of the defective cartridge, a fresh one may be
inserted into the hole bored and tamped and exploded.
Where the width or diameter of the blast-hole is considerably larger than the
hole produced by the tool, this hole may be widened by boring further around the
edges. In the case of gunpowder petards, not damaged by dampness, it is only
necessary to provide them with a fresh fuze and add a small amount of powder.
The blast-hole is then tamped and the charge exploded in the ordinary manner.
It may be mentioned that the tool herein described will also prove extremely
serviceable in removing points of drills broken off in the operation of forming the
drill-hole and also the chips or dust produced in boring, which it has been hitherto
rather difficult to remove from the blast-holes.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is,-
1. A tool for removing non-exploded cartridges having a graduated stem sub-
stantially as and for the purpose described and illustrated in the accompanying
drawings.
2. A tool for removing non-exploded cartridges having the cutting edges set at
an angle the apex being directed oppositely to the feed of the tool.
3. A tool for the safe removal of non-exploded petards or cartridges from mines
quarries or the like made of bronze or other metal not liable to give off sparks
when striking, or rubbing against stone or the like and the stem of which is
graduated and screw threaded while the cutting edges form an obtuse angle with
its apex which is turned inwardly substantially as described.
Dated this 9th day of January 1893.
W. P. THOMPSON & BOULT,
Of London, Liverpool, Nottingham, and Manchester.