Patent Application
20250224218
The invention relates to a safety unit for a detonator with the features of the preamble of patent claim 1. Furthermore, the invention relates to a use of this safety unit and a method for activating a detonator with this safety unit.
Detonators are used to initiate the active charge of various explosive devices such as explosives, bombs, rockets, mines, grenades or cartridge ammunition. In the particular case of military ammunition, there are a variety of different types of fuses that are used in different applications. One type of detonator is the proximity one, which ignites the explosive charge when it approaches the target and is known, for example, from EPO 129 679 and U.S. Pat. No. 3,839,963.
To avoid premature ignition of the active charge, safety units are used in military detonators that prevent the detonator from being activated until a defined point in time after the ammunition has been fired. Known locking units usually involve a two-stage locking mechanism in which, in a first stage, a mechanical element is released by axial forces and, in a second stage, another element is released by rotation-induced centrifugal forces.
From U.S. Pat. No. 3,595,169 a safety unit for detonators is known in which a single crescent-shaped ring element holds a spherical element with detonator charge in the deactivated position with an ignition element. First, the ring element is flattened by the acceleration-related axial forces when the ammunition is fired and then expanded by the rotation-related centrifugal forces, releasing the spherical element. The spherical element then moves into the activated position and allows the detonator charge to be ignited. A drawback of this approach is the combination of axial and centrifugal force-release locking in a single element. In the event of a defective or damaged ring element, both safety mechanisms can fail simultaneously. This is also called a “single point of failure”. That being the case, this approach is no longer permitted in modern detonators.
The NATO standardization agreement STANAG 4187 sets out the following specifications for fuse units for detonators:
From U.S. Pat. No. 4,242,963 a safety unit for detonators is known in which a spring element is used for axial securing and a wound band for centrifugal securing. The disclosed safety unit appears to meet the STANAG 4187 requirements. A drawback of this approach, however, is the complexity of the structure and components, which entails corresponding space consumption. This, in turn, limits the space for other fuse components, especially for small and medium caliber ammunition. Apart from that, the assembly process is time-consuming and, therefore, cost-demanding.
Thus, the invention is based on the object of improving the safety unit for a detonator, a use of the safety unit and a method for activating a detonator with this safety unit, and in particular of providing a safety unit for a detonator which has increased reliability, is inexpensive to manufacture and can be quickly assembled.
This object underlying the invention is now initially addressed by a safety unit for a detonator with the features of patent claim 1.
In essence, the basic principle of the invention is that the axial locking device can be moved from an axial locking device holding position to an axial locking device release position, wherein the axial locking device is in a secured state when the axial locking device is arranged in the axial locking device holding position. The axial lock engages in a first holding area of the rotary element when the axial lock is in the secured state, so that the rotary element is held in the specific, first rotary element position by means of the axial lock. The axial lock is in a released state when the axial lock is arranged in the axial lock release position. The axial lock features a deformable area, whereby this deformable area can be plastically deformed by the axial force. After and/or during the deformation of the deformable area, a movement of the axial locking device from the axial locking holding position to the axial locking release position is possible.
By means of an axial locking device designed in this way, a high level of reliability of the axial locking function can be achieved. During transport of the safety unit, e.g. in ammunition, the axial safety device remains safely in the axial safety device holding position despite the forces acting on the axial safety device during transport. The probability that the axial safety device will not release when the ammunition is fired is still very low. The axial lock itself and the entire locking unit can be manufactured inexpensively and installed quickly.
In a further embodiment of the securing unit, the rotation element is essentially spherical.
The deflected rotation element with arranged detonator results in unequal positions of the center of gravity of the rotation element in relation to the fuse unit axis. Given this uneven distribution, mass inertia moments take place, enabling the rotating element to move automatically from the first to the second rotating element position solely due to the forces acting on the rotating element during the flight of the ammunition. In this context, essentially spherical means that the spherical shape can be deviated from as long as the possibility of automatic movement of the rotary element from the first to the second rotary element position is ensured.
The deformable region preferably comprises an S-shaped metal band.
Such a deformable area can be produced easily and inexpensively. In addition, the forces required to deform such an S-shaped metal band can be calculated easily and precisely, so that on the one hand the design of the axial locking device is facilitated and on the other hand the risk of a malfunction of the axial locking device can be minimized.
In an advantageous embodiment of the securing unit, the rotation element, the axial securing device, and the rotation securing device are essentially arranged in a closing body. The end body features a groove, with the axial locking device arranged in it. The groove has a groove holding area and a groove base. The groove holding area and the groove base are arranged essentially perpendicular to each other. A retaining edge is formed between the groove base and the groove holding area. The axial locking device features a base body, wherein the metal band is connected to the base body or formed on the base body. The base body is guided in the groove. In the axial securing holding position, the metal band rests at least partially on the groove holding area, whereby the metal band is bendable due to the axial force and a mass inertia of the axial securing, so that the base body moves in the groove against the axial force and the metal band slides along the holding edge. The base body contacts the groove base in the axial locking release position.
This further simplifies the production of the axial lock. In addition, the robustness of the axial locking device is increased during use. The axial locking mechanism can be designed in a single piece. It would also be conceivable to connect the metal band to the base body using a soldering process, for example. Such a closure body is also easy to manufacture, in particular by means of fewer machining steps and/or by means of a simple casting process.
In an alternative embodiment of the securing unit, the axial securing means is connected, in particular fastened, to a closing body in the region of the metal band, in particular in the region of a groove of the closing body. As an alternative to the separate design of the axial locking device and the end body, it is, therefore, conceivable that the metal band is fixed to the end body, in particular in the area of the groove. In this case, the metal band does not slide over the holding edge when the axial locking device moves from the axial locking holding position to the axial locking release position, but only the plastic deformation of the metal band takes place. The metal band could be fixed to the end body by means of soldering or welding, for example.
In a further embodiment of the securing unit, the axial locking device has a nose. The groove also has a release area. The nose of the axial locking device engages in the first holding area of the rotating element in the axial locking holding position. The nose of the axial locking device is arranged in the axial locking release position in the release area of the groove.
By means of this nose, the rotating element can be held securely in the first holding position, e.g when transporting the safety unit, so that no unwanted ignition of the detonator charge can occur by means of the ignition element during transport. The first holding area and the nose are adapted to each other, whereby the first holding area as a recess in the rotation element has a shape that is at least very similar to, if not identical to, the nose.
In a preferred embodiment of the securing unit, the rotation lock has a blocking element. The blocking element is movable from a blocking element holding position to a blocking element releasing position, wherein the rotation lock is in a secured state when the blocking element is arranged in the blocking element holding position. The blocking element engages in a second holding area of the rotary element when the rotation lock is in the secured state, so that the rotary element is held in the specific, first rotary element position by means of the rotation lock. The anti-rotation device is in a released state when the blocking element is arranged in the blocking element release position.
The required provision of two independently functioning and functionally isolated safety systems is achieved in particular by the formation of the second holding area, which is separated from the first holding area, in particular at a distance, in the rotating element. For example, the first holding area and the second holding area are arranged and/or formed on two opposite sides of the rotary element.
The rotation lock advantageously has a delay unit. By means of the delay unit, the movement of the blocking element from the blocking element holding position to the blocking element release position can be delayed.
This ensures that the detonator charge is not ignited too early, e.g. in a gun barrel or too close to a weapon by means of the ignition element. In particular, the delay unit can be used to achieve the so-called pre-pipe safety.
In a further embodiment of the security unit, the delay unit has a band element. The blocking element is designed as a pin, whereby a movement of the pin can be blocked by means of the band element in a wound-up state. The belt element can be unwound by centrifugal force. In an unwound state of the band element, a movement of the pin is possible, whereby the pin can be further moved out of the rotation element by the centrifugal force, and the rotation lock can thus be released.
The band element in combination with the pin enables a very robust and less error-prone design of the delay unit and the blocking element.
In a further embodiment of the safety unit, the delay unit has a rack and at least one gear. The rack is coupled to the blocking element. The rack and at least one gear are in engagement with each other. Using the rack and the at least one gear, a force opposite to the centrifugal force can be applied to the blocking element, so that a movement of the blocking element from the blocking element holding position to the blocking element release position can be continuously delayed.
By means of the rack and the at least one gear, a particularly precise control of the movement of the blocking element from the blocking element holding position to the blocking element release position is possible.
In a further preferred safety unit embodiment, the delay unit has a first chamber and a second chamber. A fluid can be moved from the first chamber to the second chamber by centrifugal force. The blocking element can be moved from the blocking element holding position to the blocking element releasing position when the fluid is in the second chamber and/or the movement of the fluid from the first chamber to the second chamber and the movement of the blocking element from the blocking element holding position to the blocking element releasing position occur simultaneously.
Precise control of the movement of the blocking element from the blocking element holding position to the blocking element releasing position is also possible by means of the first chamber, the second chamber, and the fluid. The two chambers are mechanically easy to design and manufacture.
In a further embodiment of the safety unit, the blocking element can be locked using the delay unit. The blocking element movement is enabled by the centrifugal force from the blocking element holding position to the blocking element releasing position, namely out of the rotating element, by means of the delay unit after a programmed time delay and/or after a delay based on parameters such as a flight speed, a spin speed and/or a pressure difference.
That means that the point in time at which the rotation lock is released can be controlled in a particularly precise manner. The rotation lock and/or the axial lock advantageously comprises a metallic and/or polymeric material.
Such materials have the properties required for the rotational locking and/or axial locking function and are also readily available and economically viable to procure.
The object underlying the invention is further achieved by using the safety unit described above in a bottom fuse, a head fuse and/or in an ammunition of caliber 12.7 mm or larger.
By means of the safety unit, base fuses, head fuses, and/or ammunition of caliber 12.7 mm or larger can be produced with enhanced reliability and still inexpensively. The bottom fuses, the head fuses and/or the ammunition of caliber 12.7 mm or larger can still be quickly mounted.
Furthermore, the object underlying the invention is achieved by a method for activating a detonator of an ammunition with a safety unit described above, the method comprising the following sequential steps:
The detonator charge can further be ignited using the ignition element, whereby a detonation of the detonator charge causes an active charge of the ammunition to explode.
There are now a multitude of possibilities for advantageously designing and developing the safety unit according to the invention for a detonator, the use of the safety unit according to the invention and the method according to the invention for activating a detonator with this safety unit. In this regard, reference may first be made to the patent claims subordinate to patent claim 1. In the following, a preferred embodiment of the safety unit according to the invention for a detonator, a preferred embodiment of the use of the safety unit according to the invention and a preferred embodiment of the method according to the invention for activating a detonator with this safety unit are explained or described in more detail with reference to the drawing and the associated description. In the drawing shows:
The rotating element 4 is also referred to by experts as an ignition chain lock. The rotation element 4 is held in a specific, first rotation element position 4.1 by means of the axial lock 6. The rotation element 4 can further be held in the specific, first rotation element position 4.1 using the rotation lock 7. The detonator charge 5 is protected from ignition by the ignition element 3 in the specific, first rotation element position 4.1 by a wall 8 of the rotation element 4. The axial safety device 6 is designed to be released by an axial force, in particular by the axial acceleration force occurring when an ammunition having the safety unit 1 is fired. The rotation lock 7 is designed to be released by a centrifugal force, in particular the centrifugal force occurring in spin-stabilized projectiles. The axial lock 6 and the flotation lock 7 are designed to enable the movement of the flotation element 4 into a specific, second rotation element position 4.2 when both locks 6 and 7 are released simultaneously. The detonator charge 5 can be ignited in the specific, second rotation element position 4.2 by means of the ignition element 3. The ignition element 3 forms part of the igniter 2, whereby other components of the igniter 2 are not shown here for clarity purposes.
The ignition element 3, for example, features a piercing needle and/or is designed as a piercing needle, wherein the detonator charge 5 can be initiated by means of a by of the piercing needle. Alternatively, it is conceivable that the ignition element 3 is designed as an electronic ignition element. The detonator charge 5, for example, is cylinder-shaped. The detonator charge 5 further forms a surface of the rotating element 4 on at least one side of the rotating element 4.
The axial locking device 6 can be moved from an axial locking holding position 6.1 into an axial locking release position 6.2, wherein the axial locking device 6 is in a secured state when the axial locking device 6 is arranged in the axial locking holding position 6.1. The axial lock 6 engages in a first holding area 4.3 of the rotary element 4 when the axial lock 6 is in the secured state, so that the rotary element 4 is held in the specific, first rotary element position 4.1 using the axial lock 6. The axial locking device 6 is in a released state when the axial locking device 6 is arranged in the axial locking device release position 6.2. The axial lock 6 has a deformable region 6.3, wherein the deformable region 6.3 is plastically deformable by the axial force. After and/or during the deformation of the deformable region 6.3, a movement of the axial locking device 6 from the axial locking holding position 6.1 to the axial locking release position 6.2 is possible.
The rotation element 4 is essentially spherical. Two opposite sides of the essentially spherical rotation element 4 could be flattened, with an alignment of the resulting surfaces then being, for example, parallel to an axis of the then cylindrical detonator charge 5. It would also be conceivable to use a rotation element 4 with a different shape, such as a cylinder shape.
In
The deformable region 6.3 comprises an S-shaped metal band 6.4.
The rotation element 4, the axial lock 6, and the rotation lock 7 are essentially arranged in a closing body 9. It is also conceivable that the rotation element 4, the axial lock 6 and/or the rotation lock 7 is/are arranged at least partially, possibly temporarily, outside the closing body 9. The end body 9 features a groove 9.1, wherein the axial locking device 6 is arranged in the groove 9.1. The groove 9.1 has a groove holding area 9.2 and a groove base 9.3. The groove holding area 9.2 and the groove base 9.3 are arranged essentially perpendicular to each other. A retaining edge 9.4 is formed between the groove base 9.3 and the groove holding area 9.2. The axial lock 6 features a base body 6.5, wherein the metal band 6.4 is connected to the base body 6.5 or is formed on the base body 6.5.
As an alternative to the separate design of the axial locking device 6 and the end body 9, it is conceivable that the metal band 6.4 is fixed to the end body 9, in particular in the area of the groove 9.1. In this case, the metal band 6.4 does not slide over the holding edge 9.4 when the axial locking device 6 moves from the axial locking holding position 6.1 to the axial locking release position 6.2, but only the plastic deformation of the metal band 6.4 takes place.
The axial locking device 6 has a nose 6.6. The groove 9.1 also features a release area 9.5. The nose 6.6 of the axial locking device 6 engages in the first holding area 4.3 of the rotary element 4 in the axial locking holding position 6.1. The nose 6.6 of the axial locking device 6 is arranged in the axial locking device release position 6.2 in the release area 9.5 of the groove 9.1.
If the nose 6.6 of the axial locking device 6 is arranged in the release area 9.5 of the groove 9.1, the nose 6.6 does not engage in the first holding area 4.3 of the rotary element 4.
The anti-rotation device 7 features a blocking element 7.1. The blocking element 7.1 can be moved from a blocking element holding position 7.2 into a blocking element release position 7.3, wherein the rotation lock 7 is in a secured state when the blocking element 7.1 is arranged in the blocking element holding position 7.2. The blocking element 7.1 engages in a second holding region 4.4 of the rotation element 4 when the rotation lock 7 is in the secured state, so that the rotation element 4 is held in the specific, first rotation element position 4.1 using the rotation lock 7. The rotation lock 7 is in a released state when the blocking element 7.1 is arranged in the blocking element release position 7.3.
The rotation lock 7 features a delay unit 7.4. By means of the delay unit 7.4, the movement of the blocking element 7.1 from the blocking element holding position 7.2 to the blocking element release position 7.3 can be delayed.
The delay unit 7.4 has a band element 7.5. The blocking element 7.1 is designed as a pin 7.6, wherein a movement of the pin 7.6 can be blocked by means of the band element 7.5 which is in a wound-up state. The band element 7.5 can be unwound by centrifugal force. In an unwound state of the band element 7.5, a movement of the pin 7.6 is possible, whereby the pin 7.6 can then be moved out of the flotation element 4 by the centrifugal force, and thus the flotation lock 7 can be released.
For example, pin 7.6 is cylinder-shaped. The band element 7.5 features a ring 7.5.1, a spring band 7.5.2, and a securing band 7.5.3. Given a rotational movement of the safety unit 1, in particular due to the rotational movement of a projectile having the safety unit 1, the safety band 7.5.3 is released and the spring band 7.5.2 connected to the ring 7.5.1 unwinds. As soon as the ring 7.5.1 has deformed sufficiently, the blocking element 7.1, in particular the pin 7.6, is guided into the blocking element release position 7.2, since the blocking element 7.1, in particular the pin 7.6, is then no longer held in the blocking element holding position 7.3 by the ring 7.5.1 against the centrifugal force.
The deceleration unit 7.4 could also have a rack and at least one gear. Such a rack is then coupled to the blocking element 7.1. The rack and at least one gear are in engagement with each other. By means of the rack and the at least one gear, a force opposite to the centrifugal force can then be applied to the blocking element 7.1, so that a movement of the blocking element 7.1 from the blocking element holding position 7.2 to the blocking element release position 7.3 can be continuously delayed.
The delay unit 7.4 could further comprise a first chamber and a second chamber. A fluid can then be moved from the first chamber to the second chamber by centrifugal force. The blocking element 7.1 is movable from the blocking element holding position 7.2 to the blocking element release position 7.3 when the fluid is in the second chamber and/or the movement of the fluid from the first chamber to the second chamber and the movement of the blocking element 7.1 from the blocking element holding position 7.2 to the blocking element release position 7.3 occur simultaneously.
The blocking element 7.1 can also be locked using the delay unit 7.4. The movement of the blocking element 7.1 is enabled by the centrifugal force from the blocking element holding position 7.2 into the blocking element release position 7.3, namely out of the rotation element 4, by means of the delay unit 7.4 then after a programmed time delay and/or after a delay based on parameters such as a flight speed, a spin speed and/or a pressure difference.
The rotation lock 7 and/or the axial lock 6 advantageously comprises a metallic and/or polymeric material.
The described safety unit 1 is used, for example, in a base fuse, a head fuse and/or in an ammunition of caliber 12.7 mm or larger.
A method for activating the detonator 2 of an ammunition with a safety unit 1 as described above comprises the following sequential steps:
The ammunition is fired, for example, from a gun barrel. The rotation safety device 7 is preferably released only when the projectile of the ammunition has already left the weapon barrel and is at a distance from the weapon barrel at which the gun barrel itself and/or the associated weapon can no longer be damaged by the detonation of the projectile active charge.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/057134 | 3/21/2023 | WO |
