Improvements in Percussion Fuzes, More Especially Applicable for Use in Mines Infected with Fire Damp, but Applicable also to other Purposes for which Fuzes are Used.
Year: 1887

page_text: Date of Application, 18th Oct.. 1887
Complete Specification Left, 14th July, 1888
Complete Specification Accepted, 31st Aug.,
1888
Improvements in Percussion Fuzes, More Especially Applicable for
Use in Mines Infected with Fire Damp, but Applicable also to
other Purposes for which Fuzes are Used.
We FRANZ LUDWIG TIRMANN Mining Engineer and HANS TIRMANN Mechanic
both of III Sophienbrücken Strasse No. 4 Vienna in the Empire of Austria do hereby
declare the nature of this Invention to be as follows:-
The object of our Invention is to provide an improved percussion fuze which may
be worked without danger in mines infected with fire damp.
In order to avoid explosion of fire damp when using fuzes for blasting purposes it
is necessary to use a fuze which does not emit either spark or flame at the face of the
work.
This condition is not obtained by means of ordinary fuzes nor by electric ignition
which in consequence of neglected installation cause sparks or glowing of the
conducting wires at the face of the work.
The friction fuse recently introduced in practice partly avoids the above defects by
inserting the igniting material in the charge. It however presents the following
disadvantages vizt. the fuze is liable to be accidentally ignited by a short and relatively
weak pull during transportation or manipulation. On the contrary in consequence of
the long distance between the operating place and the mine to be blasted the elasticity
and the weight of the connecting cords will not admit of a short and rapid pull which
is necessary to produce the friction to ignite the fuse and consequently they frequently
miss fire.
Finally the friction fuze requires the wire to pass through a conduit pipe placed in
the timbering thereby necessitating complication and increased expense in the
timbering of mines.
By our Invention all these disadvantages are prevented.
The essential feature of our Invention is that the ignition of the primer is produced
by a striker which by means of a spring is forced towards the primer or the primer
may be connected to the striker and in this case both are rapidly thrown by the

page_text: spring or its equivalent against a resistant surface and the primer thus ignited. The
ignition of the primer effects the ignition of the detonating composition whereby
the explosion of the charge is effected.
Our improved percussion fuze consists of a tube of metal or other suitable material
fitted with a head having a hole in its centre and provided either with a cavity or with
a projection to receive the tube. Near the outer end of this tube there is provided either
a contraction or small projections to prevent the percussion cap which is placed in the
end of the tube from falling towards the head thereof the said cap being prevented
from falling out of the end of the tube by a flange thereon or by the cap being
cemented therein. The striker which may be made of metal or other suitable material
is placed within the tube and has at its rear end an ear for the reception of the hooked
end of a wire passed through the hole in the head. The main part of the striker may
be of any suitable form such for example as prismatic or cylindrical in transverse
section (in the latter case it may be provided with channels or holes along its length)
and terminating in a truncated cone.
The percussion cap consists of a metallic case partly filled with fulminate of
mercury against which is pressed a small metallic perforated plate. Upon this plate
is pasted or otherwise attached the primer which may consist of any suitable com-
position such for example as is used for toy pistols or guns. The said primer may
instead of being fixed against this small metallic plate be connected with or attached
to the striker as hereinbefore described.
The wire connected to the striker is of suitable length for operating the percussion
fuze, its inner end is bent into a hook form which enters the ear on the striker and the
outer end terminates in a loop to which the cord for pulling the striker for the purpose
of firing is attached.
Within the tube is arranged a spiral or other equivalent spring which bears at one
end against the base of the prismatic part of the striker and at its opposite end against
the bottom of the recess in the head of the fuze so that when the wire attached to the
striker is pulled the spring will be compressed between the striker and the said head.
When using our improved fuze the head is suitably fixed for example in the
timbering of the mine and then the wire is pulled so that in the first instance the
spring is compressed as before described and then by continuing to pull the wire
the hook on the end thereof will open out and be disengaged from the ear of the
striker whereupon the spring will suddenly expand and drive the striker forcibly
forward against the primer thus effecting the explosion of the charge.
Dated this 18th day of October 1887.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents.

page_text: Improvements in Percussion Fuzes, More Especially Applicable for
Use in Mines Infected with Fire Damp, but Applicable also to
other Purposes for which Fuzes are Used.
We, FRANZ LUDWIG TIRMANN Mining Engineer and HANS TIRMANN Mechanician
both of III Sophienbrücken Strasse No. 4, Vienna, in the Empire of Austria do
hereby declare the nature of our said Invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
The essential object of our Invention is to provide a percussion fuze which may be
used without danger in mines infected with fire damp.
In order to avoid explosion of fire damp when using fuzes for blasting purposes in
mines it is required to use a fuze that will not emit sparks nor flame at the face of the
work.
This condition is not fulfilled when explosions are effected by means of ordinary
fuzes, nor by electric ignition which in consequence of neglected installation may
cause production of sparks or glowing of the conducting wires at the head of the
gallery.
:-
An improved friction fuze recently introduced in practice partly avoids the above
defects by inserting the igniting portion thereof entirely into the charge of the mine,
it however presents the following disadvantages viz. the fuze is liable to accidental
ignition by a short and relatively slight pull on the connecting cord or wire during
transportation or manipulation-while in some cases in consequence of the long
distance between the place of operation and the portion of the mine to be blasted, the
elasticity and weight of the connecting cord or wire will not admit of the short and
rapid pull necessary to produce the required friction to ignite the fuze and con-
sequently it frequently miss fires.
The friction fuze also requires that the connecting cord or wire shall pass through a
conduit pipe placed in the timbering of the mine thereby necessitating complication
and increased expense in the timbering of the mine.
By means of our invention all these disadvantages are prevented.
According to our invention the ignition of the primer or detonating composition is
produced by the blow of a hammer or striker which by means of a spring or its
equivalent is thrown towards the primer, or the primer may be carried on the striker
and both the primer and the striker rapidly thrown against a resistant surface and the
primer be thus ignited so as to effect the explosion of the charge placed in the cavity.
in the mine.
And in order that our said Invention may be fully understood we shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.

page_text: Figure 1 represents in longitudinal section an improved percussion fuze constructed
according to our invention and Figure 2 is an external elevation of the same.
Figure 3 shows in longitudinal section a modification in which the detonating
composition or primer is attached to the striker.
These figures are drawn to an enlarged scale.
a is the head of the fuze which may be made of wood, metal or other suitable
material. To this head is attached a tube b which may also be of wood, metal, paper
or other suitable material.
The head a as illustrated in Figure 1 is provided with a cavity a² to receive the
tube 6 but it may if desired have a projection a2 as shewn in Figure 3 to enter the
said tube. Near the opposite end of this tube there is provided an internal annular
projection or a number of small projections. may be provided instead thereof to
prevent the percussion cap e which is placed in the end of the tube from entering too
far therein. The tube b contains the striker d which is connected to a wire g passing
through a hole in the head a and attached to the cord or wire by which the striker d
is manipulated. Interposed between the striker d and the head a is a helical spring c
for operating on the striker to effect the ignition. The striker d which may be made
of any suitable material has at its rear end an eye to which the hooked end of the
wire g is connected. The main part of the striker may be polygonal or cylindrical in
cross section (in the latter case it is provided with channels or holes in its length) and
the lower end may be in the form of a truncated cone. The cap e consists of a
metallic case partly filled with fulminate of mercury against which is pressed a small
perforated metallic plate e. Upon this plate is pasted the primer which may
consist of a composition such as is used for toy pistols or for guns of the "Lefaucheux-
System."
The said primer instead of being fixed against this small metallic plate e² may be
connected with or attached to the nose or end of the striker d as shewn in Figure 3.
The improved fuze is fitted up for operation as follows:-The wire g is passed through
the centre hole in the head a and then the spring c is placed over it. The fore end of
the wire g is hooked into the eye on the striker d. The spring e rests upon the base
of the prismatic part of the striker d and is compressed thereby when the striker is
pulled backwards by means of the wire g.
g
The wire and striker d are drawn back towards the head a so as to compress the
spring c and then the wire g is bent so as to form a loop outside the head a to prevent
its passing back through the said hole and consequently to keep the striker at a
distance from the primer when the tube b is fixed in position. The tube is now
placed over the striker d and spring c-and its end inserted in the cavity a² in the
head a and fixed therein with suitable cement. The cap e is then inserted in the end
of the tube up to the annular projection 62 and maintained in position by means of
suitable cement or by bending inwardly onto the cap the end of the tube or flaps i i
formed thereon as shewn in Figure 3. The fuze is now ready for use and when used
the tube is inserted in the blasting aperture and the head a suitably fixed for
example in the timbering of the mine and the wire g is pulled so that in the first
instance the spring c becomes further compressed and on continuing the pulling the
hook end of the wire g engaged in the eye of the striker will be opened out and
become detached from the striker whereupon the spring c will suddenly expand and
throw the striker d violently forward against the primer and thus effect the ignition
of the primer and through the cap e effect the explosion of the charge of the mine as
before described.
It will be seen that a percussion fuze constructed as hereinbefore described provides
a new method of exploding charges in mines essentially characterised by the fact that
the priming cap proper is ignited by a percussion primer which is ignited by the blow
of a striker operated by the expansive power of a compressed spring.
Our improved percussion fuse offers the following advantages:-
Danger resulting from the use of fuzes in mines infected with fire damp is obviated
as no spark nor flame is produced in the mine. The transport and manipulation of
percussion fuzes constructed according to our invention can be effected without

page_text: danger of accidental ignition in consequence of the amount of power necessary for
firing such fuze which power can be increased as desired by using a thicker connecting
wire and also for the reason that it is indispensible to fix the head of the fuze to admit
of the compression of the spring. The fuze does not require special arrangements
such as pullies, rings, beams and the like which are necessary for frictional fuze, and
there may be one or more percussion fuzes fired simultaneously from any desired
distance. The cost is much less than that of frictional fuzes.
Having now particularly described and ascertained the nature of our said Invention
and the manner in which the same is or may be carried into effect we now declare
that what we consider to be novel and therefore claim as our Invention is :-
:-
First The construction and use of a percussion fuze for shooting and blasting
purposes provided with a striker violently thrown forward so as to cause the ignition
of a percussion primer and thereby effect the inflaming of a priming for exploding the
charge substantially as herein before described.
Second-In percussion fuzes for shooting and blasting purposes a striker d in
combination with a wire g and helical spring c arranged and operated substantially as
and for the purpose hereinbefore described with reference to the accompanying
drawings.
Third In a percussion fuze for shooting and blasting purposes the striker d
pulling wire g and spring c in combination with the tube 6 containing the priming
cape and percussion primer f substantially as hereinbefore described and illustrated
by the accompanying drawings.
Fourth-In percussion fuzes the combination with a striker d pulling wire g
spiral spring e tube cape and primer f of the head a for supporting the tube b and
the parts contained therein substantially as hereinbefore described and illustrated by
the accompanying drawings.