IL118964A - Explosive logic delay element - Google Patents

Abstract

An explosive logic delay element consisting of an input explosive trail which conveys an input detonation signal through a diode junction type explosive logic element (1) out of which said signal splits into two detonation signals to propagate 1771 ז' באב התשס" ד - July 25, 2004 through two explosive trails (4) connected to an AND explosive logic device (3) wherein one said explosive trail is directly connected to said AND explosive logic device, and in the other said explosive trail a pyrotechnic delay element (2) is interposed between said diode junction and said AND explosive logic device, wherein said AND explosive logic device outputs through an output explosive trail a detonating signal, only after both said detonation split signals reach said AND explosive device.

Description

"EXPLOSIVE LOGIC DELAY ELEMENT" " "· 3 1 Ϋ ■* 3 DID 1 T* Ξ) ΤΤΉΙϋΠ The present invention relates to Explosive Logic Delay Elements (ELDE) . More particularly it relates to an explosive Logic Delay Element for providing an additional pyrotechnic delay to a safe/arm system without using an extra safe/arm device, particularly for tandem warheads or penetrators.

BACKGROUND OF THE INVENTION Conventional mechanical safe/arm systems interpose a physical barrier between the detonator explosive charge and the main charge of the warhead. This barrier is essential as the detonator comprises a primary explosive charge which may be undersirably activated when exposed to external hazards such as a fire, mechanical shock or excessive heat.

Sophisticated warheads, such as penetrators, tandem warheads and fuel air bombs, need a delayed detonation signal or two detonation signals with a predetermined delay between these signals. In these applications the safe/arm device has to generate a first detonation signal upon hitting the target and a second, delayed signal later. Electronic or pyrotechnic delay devices used for these applications should be able to withstand harsh conditions such as a very high acceleration, a mechanical shock and a nearby explosion.

In the case of a penetrating warhead, the delay has to operate properly after, or under thousands of Gees acceleration. In any tandem warhead application, the precursor detonates upon hitting the target and the delay system should survive the blast and produce a delayed detonation signal for the main warhead charge.

In many cases pyrotechnic delay has been found to be more suitable for practical applications. It is usually smaller, cheaper and more robust. It is also the only solution when there is no electrical source available. The disadvantage of using miniature pyrotechnic delay elements is that these elements contain primary explosive charges, hence an extra safe/arm device is required.

It is a primary object of the present invention to provide a miniature explosive logic delay element without the need for an additional safe/arm device. The present invention is based on a pyrotechnic logic network which consists of explosive logic elements and a pyrotechnic delay element.

Explosive logic networks are well known in the literature. They are used as components of safe/arm systems and can also serve as safe/arm systems, based on logic alone, by themselves. Explosive trails which generate OR, AND, and DIODE logic elements are known for the last twenty years .

In the US Patent No. 5,009,162 (Silvia), an explosive logic resolver netword was disclosed, for determining which detonator in a plurality of detonators is the first to detonate. The resolver network is interposed between a plurality of detonators and the explosive logic clock of a safe/arm network. Each detonator is provided with a resolver network explosive trail which intersects the resolver network explosive trails of the remaining detonators to form a plurality of explosive logic swi tches .

Another explosive logic network was described in the US Patent No. 5,311,819 (Silvia), including a first explosive path which is crossed by second explosive paths such that a detonation propagating along the second path in either direction would cut and open a first end of the first path, and will be propagated at an opposite second ehd of the first path. The two paths are connected by explosive logic elements such that a detonation propagating from the first end to the second end of the first path, will also be propagated in both directions along the second path, and a detonation propagating from the second end to the first end of the first path will cut and open both ends of the second path.

An explosive AND/NAND logic element was disclosed in the US Patent No. 3,753,402 (Menz et al).

An explosive safety junction was described in the US Patent No. 4,974,514 (Silvia). In this patent an explosive logic device is disclosed, having an inlet trail which diverges into one or more tiers of safety trails and converges to form and outlet trail. The safety trails are crossed by a control trail which propagates a control detonation wave which severs the safety trails and prevents an input detonation wave from proceeding from the inlet trail to the outlet trail to detonate the weapon .

Yet another explosive logic safeting device was disclosed in the US Patent No. 4,412,493 (Silvia), provided with an inlet explosive trail which cdnveys an inlet detonation signal to an outlet explosive charge. A control explosive trail connects the inlet explosive trail and the outlet explosive trail. A failure explosive trail is connected between the control explosive trail to the outlet explosive trail when a plurality of detonators are properly ini tiated .

A safe rocket motor igniter using sequenced initiation to an explosive logic network was described in the US Patent No. 3,973,499 (Anderson et al ) .

It is an object of the present invention to provide a simple, yet reliable explosive logic delay element.

It is another object of the present invention to provide an explosive logic delay element which is capable of withstanding the harsh conditions of penetrating warheads or the like.

BRIEF DESCRIPTION OF THE INVENTION An explosive logic delay element (ELDE) consisting of an input explosive trail which conveys an input detonation signal through a diode junction type of an explosive logic element, out of which said signal splits into two detonation signals to propagate through two explosive trails connected to an AND explosive logic device, wherein one of said explosive trail is directly connected to said AND explosive logic device, and in the other said explosive trail a pyrotechnic delay element is interposed between said diode junction and said AND explosive logic device, wherein said AND explosive logic device outputs through an output explosive trail a detonating signal, only after both said detonation split signals reach said AND explosive device.

BRIEF DESCRIPTION OF THE FIGURES FIGURE 1, is a schematic illustration of the explosive logic delay element (ELDE) according to the present invention, depicting its components, and input and output explosive trails.

FIGURE 2, is a schematic illustration of a DIODE junction and illustrates the corner effect in an explosive trail. FIGURE 3, is a cross section illustration of a typical penetrating warhead containing an ELDE in addition to a safe/arm device.

FIGURE 4, illustrates schematically and application of an ELDE in a tandem warhead.

DETAILED DESCRIPTION OF THE FIGURES AND INVENTION Figure 1 illustrates schematically an explosive logic delay element (ELDE) according to the present invention. The ELDE 5 according to Fig. 1 comprises the following three basic components: , - a DIODE junction (1), - a miniature pyrotechnic delay element (2), and - an AND type of an explosive logic element (3) . These elements are connected by explosive trails (4) .

When an input detonation signal reaches the DIODE junction (1) , it splits at that one signal travels directly to the AND explosive logic element (3) , whereas the other signal reaches the pyrotechnic delay element (2) and after being delayed by that delay element propagates to the AND explosive logic element. Only when the later signal reaches the AND logic element it does produce an output detonation signal, accomplishing its designed task.

The detonation trails consist of a secondary explosive with a small critical diameter preferably in the range of 0.2 to 0.5 mm. The critical diameter of an explosive is defined as the minimum diameter at which a steady-state detonation will propagate. Therefore, any detonation trail cross-section must be larger than the critical section of about 1 mm width or more. Commonly an extrudable secondary explosive is used, like TS-20 or XTX-8003 which is a mixture of 80% PETN (Propanediol Dl-Nitrate) and 20% binding material.

- - , The AND element needs two sequential detonation signals to allow the detonation signal to propagate through the intersection gate.

In Figure 2 when the ELDE receives a legal detonation signal from the fuse at the input point A (6) it splits in the DIODE junction (7) and propagates through trail B (8) and trail C (9) . Trail B does provide the first legal detonation signal to the AND gate waiting for the delayed signal propagating through the pyrotechnic delay element to arrive and produce an output signal through the AND gate. Any illegal detonation signal initiated from the pyrotechnic delay element, containing primary explosive trail, is provided with an explosive logic network for conveying failure of the safe/arm system. Typical delay times are generally in the range of between 0.05 to 0.2 seconds .

A typical pyrotechnic delay element usually consists of three elements: a delay composition which can be made of BCR (Boron Calcium Chromate) or other delaying substances; a primary explosive material, such as lead azide, and an output composition. ' Figure 3 illustrates a typical application of the ELDE in a penetrating warhead. The ELDE is an integral part of the warhead, connected pyrotechnically to the fuse.

- - , Upon hitting the target, the fuse produces a detonation signal input to the ELDE, and the ELDE produces a delayed detonation signal to the main explosive charge of the warhead.

Figure 4 illustrates schematically another typical application of ELDE in tandem warheads. Here a detonation signal activates first the precursor (15) and then, traveling through the ELDE a delayed signal activates the main warhead charge (16) .

Although the invention was described by the above particulars, it should be understood that a person skilled in the art after reading the present specification will be in a position to insert slight modifications, but without being outside the invention as covered by the appended Claims.

Claims (11)

118,964/3

1. C L A I M S :- 1; Art explosive logic delay element consisting of an input explosive trail which conveys an input detonation signal through a{ diode junction type explosive logic element, out of which said signal splits into two detonation signals to propagate through two explosive trails connected to an AND explosive logic device, wherein one said explosive trail is directly connected to said AND explosive logic device, and in the other said explosive trail a pyrotechnic delay element is interposed between said diode junction and said AND explosive logic device, wherein said AND explosive logic device outputs through an output explosive trail a detonating signal, only after both said detonation split signals reach said AND explosive device.

2. A device according to Claim 1, wherein said explosive trails consist of a secondary explosive with a small critical diameter preferably in the range of between 0.2 to 0.5 mm.

3. A device according to Claim 2, wherein said secondary explosive is an extrudable explosive.

4. A device according to Claim 3, wherein said secondary explosive is a TS-20 explosive.

5. A device according to Claim 3, wherein said secondary explosive is a XTX-8003 explosive.

6. A device according to Claim 3, wherein said secondary explosive consists of a mixture of 80% PETN (Propanediol DI-Nitrate) and 20% binding material.

7. A device according to Claim 1, wherein said pyrotechnic delay element has a delay time in the range of 0.05-0.2 seconds.

8. A device according to Claim 7, wherein said pyrotechnic delay element consists of three elements: (1) a delay composition. (2) a primary explosive. (3) an output composition.

9. A device according to Claim 8, wherein said delay composition comprises BCR (Boron Calcium Chromate).

10. A device according to Claim 8, wherein said primary explosive consists of lead azide.

11. A device according to Claims 1 to 10, substantially as described in the spec fication, the attached Figures and Claims. For the Applicants, Simon Lavie Patent Attorney