Year: 1898

page_text: Date of Application, 16th July, 1898-Accepted, 20th Aug.,
1898
I, HEINRICH BETTERMANN, of Troisdorf, near Cologne, on the Rhine, Manager, 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 state-
ment:-
In electric fuses at present used for blasting purposes a priming composition is
ignited by an electric incandescence or spark and this ignition is transferred im-
mediately to the detonating composition of the cap, so that the explosion of the
cartridge connected with such fuse is effected directly the electric current is closed.
In blasting operations, where 60 and more cartridges are fired together electrically,
it has been shown, that it is of greatest importance, to cause the inner cartridges to
explode before the exterior ones, as then the tensions within the material operated
on are increased and consequently the effect of the exterior cartridges is nearly double
as strong than if a simultaneous exploding of all the cartridges had been effected.
The present invention relates to an electric time fuse, by which the before said
purpose is obtained in a simple and secure manner.
The fuse shown in the annexed drawing, which is represented in Fig. 1 in a
vertical section, is composed of the exploding cap a, a powder composition deter-
minating the time taken for the ignition of the cap (Fig. 4) the real fuse c (Fig. 2)
and a protecting cover d (Fig. 3) which surrounds the fuse cand the powder column b
and connects both with the exploding cap a.
The powder column 6 consists of slowly burning powder and can also be replaced
by a priming composition or a piece of priming string or the like, the fuse c can be
of any construction and formed as an incandescent or spark fuse. The protecting
cover d made of metal, paper, or any other suitable material has preferably in about
in its middle two or more openings e, which serve for the escape of the gases
developed during the burning of the powder column b. These openings e are pasted
over with paper or any other suitable material which of course is pierced before using
the fuse, and the whole fuse is suitably coated with varnish in order to make it water
tight.
When in a cross working or tunnel construction the inner cartridges f ( Fig. 5) are
provided with the usual fuses, and the exterior cartridges g with the above described
time fuses, the inner cartridges are exploded directly the electric current is closed
whilst in the exterior cartridges the fuse c first ignites the slow burning powder
column b, and the detonation of the cap a is effected only after the complete burning
of the column b.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim is :-
1. An improved electric time fuse for blasting purposes, wherein between the real
fuse c and the detonating cap a there is inserted a column 6 of slowly burning

page_text: powder, priming composition or priming string, substantially as and for the purpose
described.
2. An improved electric time fuse as in Claim 1 wherein openings c are provided
in the protecting cover d for the escape of the gases developed during the com-
bustion of the column b.
PAL UITE
HERBERT HADDAN & Co.,
Agents to Applicant, 18, Buckingham Street, Strand, W.C., London.