Note: Descriptions are shown in the official language in which they were submitted.
lli98~
-- 1 --
" FUSE FOR A ROCKET PROJECT ILE "
The invention relates to a fuse for a rocket project-
lle, having a detonator which is fixed on a slider and is
dlsplaceable in the axial direction of the projectile from
a safety position into an armed position in which the
detonator is located next to a transfer charge, and having
blocking members and a displaceable safety element for
holding the slider in the safety position and for releasing
the slider for its displacement into the armed position.
In a known fuse of this type, disclosed in Swiss
Patent Specification No. 294,729, an additional explosive
charge, or the pressure of the gases from the rocket pro-
pellant charge, is required for displacing the safety
element. The fuse of the projectile is thus dependent on
the rocket propulsion unit which is located immediately
behind the projectile. This dependence is a disadvantage,
ln particular if lt is not possible to arrange the rocket
propulsion unit lmmediately behind the projectile. The
known fuse also has the disadvantage that the activation
of the slider takes place when the rocket propellant charge
begins to burn off, that is to say at the start of the
trajectory. Admittedly, the slider re~ains in the safety
position under the action of the inertial force which is
effective up to the end of burning of the propellant charge,
but in the case of malfunctioning of the propulsion unit,
for example if the propulsion unit becomes extinguished
within the safety zone in the forefield, the slider wlll
pass into the armed position immediately after acceleration
ceases.
The object of the present invention is the provision
o~ a fuse which does not re~uire any gas pressure from the
rocket motor to displace the detonator into its armed
pos~tion and ln which the slider does not pass into the
armed position when the acceleration of the projectile
ceases within the safety zone in the forefield.
To achieve this object, in the fuse according to the
invention the safety element comprises an inertial body
~988~;
-- 2 --
which, on acceleration of the projectile, is displaceable
against the force of a spring in order to drive a retarding
mechanlsm and release the blocking members after the
retard~ng mechanism has run down, and, in the safety pos-
ition thereof, the detonator is located in front of thetransfer charge.
An illustrative embodiment of the fuse according to
the invention is described in detail in the following text
by reference to the attached drawing in which:
Figure 1 shows a longitudinal section through a hollow-
charge project1le having a rocket drive;
Figure 2 shows a longitudinal section through the rear
fuse of the hollow-charge projectile in its safe transport
positlon, on an enlarged ~cale;
lS Figure 3 shows a cross-section along line III-III in
Figure 2;
Figure 4 shows a cross-section along line IV-IV ln
Flgure 2;
Figure S shows the same as Figure 2, but simplified
and immedlately before armlng;
Figure 6 shows the same as Flgure 5, but already armed;
and
Figure 7 shows the same as Figure 5, but armed and
blocked.
As shown in Figure 1, the projectile in which the fuse
1 according to the invention is located, has a case 2 on
which a cartridge-like attachment 3 is fixed, to receive
the fuse 1. A hollow charge 4 is located in the interlor
of the case 2. A percussion fuse la is fitted on the tip
of the projectile. This percussion fuse la is presumed to
be known and ls therefore not described in greater detail.
The fuse 1 located in the attachment 3 partly protrudes into
the interior of the hollow charge 4. The projectile has a
rocket drive which is visible in Figure 1 but which is not
described in more detail since it does not form part of the
11~9886
-- 3 --
subject of the invention.
As shown in Figure 2, the fuse 1 has a casing which
ls formed by a cartridge 5, a cartridge base 6 and a guide
piece 7. The casing 5, 6 and 7 is sub-divided into two
S chambers by a disc 8. A transfer charge 10 is present in
the front chamber. The disc 8 and $he transfer charge 10
are supported on a drilled shoulder 9 of.~he cartrldge 5,
which has orlfices 12 through which the chamber and the
transfer charge 10 are connected to the interior of the case
2 in which the hollow charge 4 is located. The rear cha~ber
of the casing 5, 6 and 7 contains a displaceable inertial
body 13 and a bolt 14, which is arranged parallel to the
axis of the cartridge and which, according to Figures 2 and
4, protrudes through a bore 16 of the inertial body 13.
The front part of the bolt 14 has a smaller diameter than
the rear part which has the form of a rack 15. A spring 17
which surrounds the front part of the bolt 14 is backed up
on one side on a should'er 19 of the bolt 14 and on the other
side on a wall 18 of the inertial body 13. This spring 17
tends to push the inertial body 13 against the disc 8 and to
push the bolt 14 against the cartridge base 6.
As shown in Figure 4, the inertial body 13 has a
longitudinal groove 20 which ls parallel to the axis of the
cartridge 5 and ln which a retarding mechanism 1~ located.
This retarding mechanism comprises a rotatably mounted,
toothed flutter body 21 (Figure 2) which can be driven by a
pinlon 22 (Figure 4) vla a form-ground gear 23 and a number
of gears (Figure 2) not marked ln more detall. The pinion
22 engages with the rack 15 of the bolt 14 S9 that the
flutter body 21 i5 driven via the pinion 22 and the gears
mentloned when the lnertial body 13 is displaced relative
to the bolt 14. The complete retardlng mechanism ls mounted
within the inertial body,
A cap carrler 24 (Figure 2) r which is composed of a
flange 25 and a cylindrical part 26, protrudes into a central
86
-- 4 --
bore 11 of the guide body 7. In the position shown, the
flange 25 makes contact on one side with the rear side of
the disc 8 and on the other side with the front face of
the inertial body 13.
At its rear end, the cap carrier 24 has a central bore
27, the longitudinal axis of which coincides with the long-
ltudinal axis of the cartridge 5. A control bolt 28 which
protrudes into the said central bore 27 of the cap carrier
24 is fixed to the inertial body 13. The control bolt 28
consists of a front part 28b of a smaller diameter than
that of the rear part 28a. The two parts 28a and 28b are
joined to one another by a part 29 in the shape of a
truncated cone.
At the front end of the cylindrical part 26 of the
cap carrier 24, there is a detonator cap 32 - with an open
front - ln a thin-walled cartridge 33 which protrudes into
the conlcal shape of the hollow charge 4 (Figure 1). In
the transport po~ition'shown, the detonator cap 32 is in
the interior of the guide piece in front of the transfer
charge 10.
As wlll be seen ln Figure 3, the flange 25 of the cap
carrier has three radially pointing bores 30, the three
angles between these three bores30 being equal. In each
of these bores 30, there is one blocking bolt 31, the outer
ends of these blocking bolts each having a head 31a in the
shape of a truncated cone. These blocking bolts 31 are
dlsplaceable and are supported on the said control bolt 28.
The flange 25 also has abore 34 which is parallel to
the axis of the casing and into which the front end of the
said bolt 14 protrudes.
Behind the disc 8, the inner wall of the cartrldge 5
has an annular grooye 36 which i~ delimited at the bottom
by a conical surface 35. Below this conical surface 35,
there are three bore sectlons 37, 39 and 38, of which the
upper bore section 37 has a smaller diameter than the central
86
bore section 39 and the central bore section 39 has a
smaller diameter than the lower bore séction 38 This
lower bore section is delimited by two conical surfaces
38a and 38b, and the central bore section 39 is delimited
at the top by a conical surface 39a.
As shown in Figure 2, the heads 31a of the blocking
bolts 31 protrude into the annular groove 36 and the inner
end of the blocking bolts 31 is supported on the thicker
part 28a of the control bolt 28. In Figure 6, the heads
31a of the blocking bolts 31 are in the lower bore section
38 and the inner end of the blocking bolts 31 can likewise
be supported on the thicker part 28a of the control bolt
28. However, lf the heads 31a of the bolts 31 are in the
central bore section 39, the blocking bolts 31 can only be
lS supported on the thinner part;28b of the control bolt;
and if the heads 31a of the bolts 31 are ln the upper bore
section 37, the blocking bolts 31 cannot then be supported
on either of the two p~rts 28a and 28b of the control bolt
28.
The mode of action of the fuse described is as follows:
In the transport positio~ of the fuse before the
projectile ig fired, the spr1ng 17 tends to push the inert- ¦
ial body 13 and the cap carrier 24 into their frontmost
position ~hown in Figure 2. ~he heads of the blocking bodies
- 25 31 protrude into the annular groov~ 36 and are held ln this
position by the thicker part ~8a of the control bolt. The
pinion 22 of the retarding mechanism engages with the upper
end of the rack 15.
In the case of shocks during transport of the project-
ile, the inertial body 13 can be displaced by small amounts.
The retarding mechanism, however, prevents larger displace-
- ments of the inertial body due to its resistance. It is
therefore not possible for the blocking bodies 31 to come
out of the annular groove 36 since, during transport, they
are contin~ously ln contact with the thlcker end ~8a of the
1119~8~
- 6 -
control bolt 28. In the case of a possible displacement
due to transport shocks, the spring 17 will lmmediately
return the inertlal body 13 back into its starting position.
Even if the blocking bolts 31 are supported on the thinner
part 28b of the control bolt 28, the heads 31a of the
blocking bolts cannot come out of the annular groove 36
and the cap carrier 24 is thus held in its frontmost pos-
ition. The detonator cap 32 is therefore in its safety
position and not in the zone of the transfer charge 10.
On firing the projectile and during its acceleration
after the rocket propellant charge has been ignited, an
inertlal force acts on the inertial body 13, and this force
tends to push the inertial body to the rear against the
force of the spring 17 and against the braking action of
the retarding mechanism. This displacement is, however,
strongly slowed down by the retarding mechanism.
The control bolt 28 has such a length that the block-
ing bolts 31 are released only when the retarding mechanism
has fully run down, that ls to say when the pinion 22 is at
the lower end of the rack 15, as shown in Figure 5. As
soon as the pinion 22 has reached the lower end of the rack
15, the braking action of the retarding mechanism ceases
and the inertial body 13 suddenly passes into its rearmost
position shown in Figure 6. In this rearmost position of
the inertial body 13, the blocking bolts 31 are no longer
underplnned ~y the control bolt 28 and are thus pushed
radlally lnwards by the conical surface 35 in the bores 30
o~ the flange 25. The cap carrier 24 can, under the action
of the said inertial force, likewise be displaced lnto the
position shown in Figure 6. ~he blocking bolts 31 are
then again in contact with the thicker part 28a of the
control bolt 28 and the heads 31a of the blocking bolts 31
thus protrude into the bore section 38, as a result of which
the cap carrier 24 is secured in its armed position and can
no longer be d1splaced forward, Th1s 1s prevented by the
1119~386
spring 17 which presses the inertial body 13 against the
flange 25 of the cap carrier 24. At the same time, the
thicker part 28a of the control bolt 28 remains in the
zone of the blocking bolts 31 (Flgure 7).
~hen the projectile hits a target, the percussion fuse
la is ignited causing the detonator cap 32 of the rear fuse
1 to respond. The detonator cap in turn ignites the trans-
fer charge 10 and the latter ignites the hollow charge 4.
The truncated conical part 29 of the control bolt 28
has the effect that, on displacement of the cap carrier 24
from its safety position into i~s armed position according
to Figure 6, the heads 31a of the blocking bolts 31 pass
behind the conical surface 38b and the cap carrier 24 is
thus secured ln its armed position.
.
