Improvements in the Process and Tools for Clearing Bore Holes of Bore Dust.in Blasting Rock and the like.
Year: 1897

page_text: Date of Application, 22nd Apr., 1897-Accepted, 5th June, 1897
Improvements in the Process and Tools for Clearing Bore Holes of
Bore Dust.in Blasting Rock and the like.
I, FRANZ VOLPERT, Doctor, of Dortmund, in the Empire of Germany, 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 effectual removal of bore dust from bore holes in blasting rock and the like
is of the greatest importance in using and ensuring the explosion of the blasting
material as the bore dust left behind may easily separate the cartridges owing to the
formation of intermediate layers or plugs and in such cases the explosion of the
portion of the charge left under these layers is often prevented. These "resting
charges" have frequently given rise to serious accidents in the use of dynamite, when,
through inadmissable boring out or inadvertent side tapping on the so-called plug left
standing a sudden explosion of the cartridge still remaining takes place. The same
thing may happen with non-exploded cartridges in breaking through or in clearing
away between the blast points of the rock, coal or the like.
Such occurrences may possibly be avoided if the bore holes are cleaned out with
great care with the ordinary scraper, and the cartridges are placed with certainty one
on the other without any intermediate layer. The scraper Fig. 1 is a strong wire,
the right angled bent end of which is either flat or spoon shaped. By repeated
insertions and withdrawals of the scraper the bore hole is more or less freed of bore
dust. The object of the present invention is to complete this cleaning out.
A cylindrical brush of metal wire, bristles, fibres or the like, Fig. 2, or a brush in
the form of a roller made by the over winding or insertion of the cleaning wisps in
a cylindrical mantle or block; exactly as ordinary cylindrical brushes are made, is
attached to a wire or tube corresponding to the depth of the bore holes, and a sleeve
provided with a cord, chain or wire and consisting for example of a tube or a tube
shaped net of metal or other material Fig. 3 is forced thereover for the pressing
together of the brush. The enclosing sleeve is made to suit the diameter of the bore
hole for the purpose of convenient insertion therein leaving of course sufficient play
between the sleeve and the surface of the bore hole so that little or no bore dust is
carried downward and the chain is made to suit tho depth of the bore hole.
Pressed together in the sleeve the brush is brought to the bottom of the bore hole.
The sleeve is then withdrawn allowing the brush to extend outwards, Fig. 4, and rest
against the surface of the bore. If, after the sleeve is slid back over the wire, the
brush is drawn out of the bore hole preferably with a rotating movement, the removal
of the bore dust is well and easily effected.
It is immaterial to the spirit of the invention whether the brush or the tube are
shorter or longer, or whether another than the circular shape be given to the brush or
the sleeve.
As a modification of the tool for the same purpose a hollow body of rubber or the
like with or without cleaning wisps provided thereon might be used, fastened to a
hollow rod, the cleaning out being effected by inflating the hollow body of rubber
after its insertion in the hole and then withdrawing it. A cylindrical brush could
also be used having for example brush wisps movable hinges and which on insertion
into the bore hole lie close to the wire whilst on withdrawal thereof they would stand
out at right angles and thus effect the cleaning out of the bore dust. The same effect