A high-safety delayed-action grenade fuse

Abstract

The application discloses a high-safety delay grenade fuze, mainly composed of a fuze body, a sliding block seat, a pressing screw, a delay tube, a firing mechanism, a safety and release isolation mechanism, a transmission explosion sequence and an observation window. The firing mechanism is a plate hammer type structure driven by a torsion spring, located at the upper part of the fuze; the safety and release isolation mechanism mainly comprises an explosion isolation mechanism, a redundant safety mechanism and a delay release explosion isolation mechanism, arranged in the inner cavity of the fuze; the observation window is arranged on the outer contour of the middle part of the fuze body, used for observing the position of the explosion isolation member. The explosion isolation mechanism is a spring-driven sliding block mechanism; the redundant safety mechanism indirectly or directly implements safety on the sliding block through two safety pins and a handle piece and a safety lever, and the safety is released through different manual actions; the delay release explosion isolation mechanism is realized by the delay tube and the memory alloy safety spring. The fuze meets the relevant requirements of GJB 3194-1998 'Safety Design Guidelines for Manually Laid Weapons', and has the advantages of compact structure and low cost.

Description

Technical Field

[0001] This invention pertains to the overall design of fuses, specifically relating to a high-safety delayed-action grenade fuse. Background Technology

[0002] As a type of throwable individual weapon, the safety of hand grenades is of paramount importance. Based on years of practical experience with MIL-STD-1316 "Design Guidelines for Fuze Safety," the US military has issued a specific safety design standard for hand-placed weapons, primarily hand grenade fuses: MIL-STD-1911 "Design Guidelines for Safety of Hand-Placed Weapons." my country adopted this standard and formulated GJB 3194-1998 "Design Guidelines for Safety of Hand-Placed Weapons." Its requirements include explosion-proof design, redundant safety mechanisms, delayed-release explosion-proof design, permissible guided explosives, safety system failure rate, fault tolerance, human factors engineering (structural simplicity, robust structure, assembly and setting, manual safety mechanisms, operational status indication), internal energy storage, material compatibility, electric ignition energy dissipation, electrical and electromagnetic environment adaptability, explosive disposal, and fireproofing.

[0003] According to the US military standard manual MIL-HDBK-145C, "Active Fuze Catalog," none of the 17 grenade fuse models listed meet the requirements of MIL-STD-1911, "Safety Design Guidelines for Hand-Placeed Weapons," including the most basic requirements for explosion-proof safety and redundant safety features. In recent years, some domestic products have been developed according to GJB3194-1998, but some still fail to meet explosion-proof safety requirements, some fail to meet redundant safety features, or have overly complex structures, making operation inconvenient and costly.

[0004] In chronological order, the following eight patents are listed: Chinese Patent CN200820074301.9 "A Hand Grenade / Grenade with Wireless Remote Control Detonation Function", Chinese Patent CN201010536251.3 "A Hand Grenade Fuze", Chinese Patent CN201120400753.3 "Hanging Bomb Grenade", Chinese Patent CN201220541810.4 "Hand Grenade with Boosting Device", and Chinese Patent CN201520491352.1. The patents CN201910359787.3 ("Modular Acceleration Extended Range Dual-Delay Safety Trigger Type Super Grenade"), CN202010668209.0 ("Rotating Grenade"), and CN201910207313.7 ("An Airburst Grenade") all involve or provide fuses that are traditional non-explosion-proof fuses with a sensitive inline explosion sequence. These designs violate modern fuse safety design principles and do not meet the detailed and systematic requirements of GJB 3194-1998 "Safety Design Guidelines for Manually Deployed Weapons".

[0005] The paper "Electronic Trigger Fuze for Hand Grenades Using Magnetoelectric Generators" (Sun Zhongsheng, Guo Junxian, Hao Yimin, et al., *Journal of Detection and Control*, 2010, No. 2) mainly discusses the power supply and electrical issues of electronic hand grenade fuses, without addressing the overall structure, safety features, and the construction and working principle of the explosion-proof disarming mechanism. The paper "Research on Electromechanical Hand Grenade Fuzes" (Li Ning, Qi Xinglin, Cui Ping, et al., *Sichuan Ordnance Journal*, 2007, No. 5) discusses the concept, principle, and development overview of electromechanical hand grenade fuses, summarizing their main characteristics, but without introducing or analyzing the specific structure and safety principles of the fuse. The digital grenade fuse described in the paper "Research and Design of Digital Hand Grenade Fuze" (Zhou Ming'an, Guo Tiantian, Cheng Xiaodong, et al. Sichuan Ordnance Journal, No. 8, 2014) is an improvement on the traditional non-explosion-proof fuse that uses a sensitive in-line explosion sequence, but it is still inherently unsafe and does not meet the requirements of GJB 3194-1998 "Safety Design Criteria for Manually Deployed Weapons".

[0006] In recent years, scholars have paid attention to the safety design of grenade fuses and are making progress towards meeting the requirements of GJB 3194-1998 "Safety Design Guidelines for Manually Deployed Weapons". Chinese Patent CN202211275114.8, "A Safe Fragmentation Grenade with a Quasi-Spherical Integrated Fuse-Fuse Structure", describes an integrated fuse-fuse grenade that fully utilizes the movement characteristics of the detonator base, achieving a combination of safety, misalignment explosion-proof, and firing functions. It employs a nut and safety ball safety method, different from the traditional grip, combined with a pull-pin safety to form redundant safety. The simplicity and robustness of the structure, as well as the manual safety components, also meet ergonomic requirements. Chinese Patent CN202211470002.8, "A Safe Delayed Fuze for Hand Grenades", discloses a grenade fuse that uses an externally removable explosion-proof bolt and explosion-proof mechanism between the sensitive impact cap and the insensitive flame delay tube. The screw, while providing explosion-proof protection for the fuze, forms a redundant safety mechanism with the grip safety mechanism, improving fuze safety. Chinese patent CN202310682349.7, "A Safe Type Time-Setting Fuze for Smoke Canisters and Hand Grenades," describes a time-setting fuze for hand grenades. Its ignition mechanism's grip safety and time-setting mechanism achieve redundant safety through separate manual actions to disarm the safety mechanisms. The horizontal rotor in the safety and disarming mechanism and the vertical rotor in the time-setting mechanism together constitute the fuze's explosion-proof system. The position of different delay pyrotechnics can be adjusted by manually rotating the vertical rotor seat of the time-setting mechanism to achieve short or long delay settings, providing controllable delay time. These three patents also incorporate fire-resistant functionality, representing a substantial improvement in safety compared to the aforementioned eight patents. They basically meet the relevant requirements of GJB 3194-1998, "Safety Design Guidelines for Manually Installed Weapons," regarding the safety design of non-electric fuzes. Summary of the Invention

[0007] The purpose of this invention is to provide a high-safety delayed-action grenade fuse that fully meets the relevant requirements for non-electrical principle fuses in GJB3194-1998 "Safety Design Guidelines for Manually Deployed Weapons". Specifically, it includes explosion-proof, redundant safety, delayed explosion-proof release, permissible guided explosive, safety system failure rate, fault tolerance, human factors engineering (simple structure, robust structure, assembly and setting, manual safety, working status indication), internal energy storage, material compatibility, explosive disposal, and fireproofing.

[0008] The technical solution for achieving this invention is a high-safety delayed-action grenade fuse, comprising a fuse body, a slider seat, a pressure screw, a delay tube, a firing mechanism, a pull pin safety mechanism, a grip safety mechanism, a delayed-release explosion-proof mechanism, an explosion-proof mechanism, a detonation sequence, and an observation window. The slider seat, delay tube, delayed-release explosion-proof mechanism, explosion-proof mechanism, detonation sequence, partial pull pin safety mechanism, and partial grip safety mechanism are disposed within the fuse cavity formed by the pressure screw-sealed fuse body. The firing mechanism is a torsion spring-driven flapper hammer structure located at the upper part of the fuse body. The pull pin safety mechanism and grip safety mechanism form redundant safety against the explosion-proof mechanism, and together with the delayed-release explosion-proof mechanism and the explosion-proof mechanism, form a safety and release isolation mechanism. The detonation sequence is arranged along the fuse axis, with a sensitive linear section at the top, a staggered isolation section in the middle, and a blunt-sensitive linear section at the bottom. The observation window is located on the outer contour of the middle part of the fuse body. The firing mechanism mainly includes the fuse body, flapper, hammer, torsion spring, flapper shaft, impeller cap, and impeller cap seat. The flap shaft is located in the horizontal hole on the upper left side of the fuse body to fix the flap and the torsion spring. The hammer is fixed to the flap by riveting or welding. The impact cap is fixed in the cap seat by the constriction or spot riveting and screwed into the threaded hole on the upper part of the fuse body on the axis. The grip safety mechanism mainly includes a fuse body, a slider seat, a grip, a torsion pin, a torsion pin pull ring, a grip shaft, a sealing cup, a sealing spring, a rubber ring, a safety rod, and a safety rod spring. The tip of the safety rod passes through the stepped hole on the upper right side of the fuse body and is inserted into the longitudinal through hole on the right side of the slider seat. The safety rod spring is located between the shoulder of the safety rod shaft and the bottom surface of the stepped hole on the right side of the slider seat. The torsion pin and the torsion pin pull ring are connected by a collar-type flexible connection. The torsion pin passes through the pre-drilled hole on the grip and is inserted into the transverse hole of the left boss of the fuse body. The hook at the front end of the grip hooks the grip shaft located on the right cantilever of the fuse body. The main body of the grip is against the outer wall of the projectile, and at the same time, it presses the sealing cup and sealing spring located in the stepped hole on the upper right side of the fuse body, thereby pressing the safety rod below the sealing cup and the rubber ring between the sealing cup and the bottom of the stepped hole. The explosion-proof mechanism mainly includes a fuse body, a slider seat, a pressure screw, a slider, a slider spring, a flame detonator, a recovery cylinder, and a recovery cylinder spring. The recovery cylinder spring is located inside the recovery cylinder and is also installed in the transverse groove on the side of the slider. The flame detonator is fixed to the longitudinal stepped hole on the right side of the slider by spot riveting. The slider spring is installed in the blind hole at the right end of the slider, and its other side abuts against the inner wall of the fuse body. The pressure screw tightens the slider seat into the inner cavity of the fuse body through a threaded connection, forming the sliding chamber of the slider. The pull pin safety mechanism mainly includes a fuse body, a slider seat, a cotter pin, a safety pin pull ring, and a safety pin. The safety pin has a first through hole on each side. The first through hole on one side of the safety pin connects to the safety pin pull ring, and the other side passes through the radial through hole in the middle of the fuse body, through the slider seat and the transverse hole on the slider located in the rectangular groove at the bottom of the slider seat, and exits on the other side of the fuse body. It is locked by the cotter pin passing through the first through hole on the other side of the safety pin, realizing an independent safety for the explosion-proof component of the slider.The safety pin in the pull pin safety mechanism has a necked-down structure in the middle, that is, the diameter of the part in the middle that mates with the slider is smaller than that at both ends. Under normal circumstances, the slider is positioned by the safety rod. When the safety rod is misinstalled, missing, broken or in other situations where the positioning of the safety rod fails, the slider is pushed by the slider spring and its slider hole mouth catches into the necked-down part of the safety pin, and the fuze enters the fail-safe state. After that, the safety pin is locked by the slider and cannot be normally withdrawn. The delayed arming and disarming mechanism mainly includes a fuze body, a slider seat, a delay tube, a safety rod, a safety rod spring, a shape memory alloy safety spring and a safety pin. The safety pin is located in the radial through hole in the middle of the slider seat. Due to the tension of the shape memory alloy safety spring, the left side of the safety pin abuts against the shape memory alloy safety spring, and the mushroom head on the right side catches into the annular groove of the safety rod, realizing the restriction of the axial movement of the safety rod, and further restricting the slider to ensure the safety of arming and disarming. When the delay tube is ignited, after a predetermined arming and disarming delay, the shape memory alloy safety spring shrinks due to heat, enabling the safety pin to retract and move, thereby releasing the safety rod. The safety rod is pulled out of the slider under the push of the safety rod spring, releasing the slider, realizing the function of delayed arming and disarming. The upper sensitive in-line part of the train of the hand grenade fuze includes an impact primer and a delay tube; the middle misaligned isolation part is a flame detonator; the lower insensitive in-line part includes a detonating fuse, a first booster tube and a second booster tube arranged in sequence. The impact primer is fixed in the primer seat by caulking or riveting and is screwed into the threaded hole on the axis in the upper part of the fuze body together with it; the delay tube is fixed in the delay tube hole on the slider seat below the primer seat by riveting; the flame detonator is fixed in the longitudinal stepped hole on the right side of the slider by riveting, and is misaligned with the delay tube and the detonating fuse in the assembled state; the detonating fuse is fixed at the upper end of the pressure screw by caulking; the lower end of the pressure screw sequentially fixes the first booster tube, the support cylinder and the second booster tube in the blind hole at the bottom of the pressure screw by caulking. Each explosive element in this train has a single function, high reliability, and is convenient for development and quality control. The two-stage booster tube design makes the second booster tube located at the center of the charge, which helps the spatial uniform distribution of the fragments of the projectile body. The observation window of the hand grenade fuze mainly includes a fuze body, a slider seat, a slider and a convex viewing lens. On the front of the outer contour of the frustum part of the fuze body, slightly to the right and on the right side of the through hole where the safety pin is located, a round hole is additionally opened and communicated with the rectangular groove below the slider seat. A convex viewing lens is installed outside the round hole to observe whether the position of the slider in the inner cavity of the fuze body is in the disarmed position. Before assembly, it is necessary to apply a marking with a fluorescent green background and the white Latin letter "S" or the Chinese character "An" printed on it in the middle of the side of the slider; apply a marking with a fluorescent red background and the black Latin letter "A" or the Chinese character "Wei" printed on it on the right side of the slider. If the marking with a fluorescent green background and the white Latin letter "S" or the Chinese character "An" printed on it is observed through the convex viewing lens in the observation window, it means that the fuze is in the armed state; if the marking with a fluorescent red background and the black Latin letter "A" or the Chinese character "Wei" printed on it is observed, it means that the fuze is in the disarmed state.The grenade fuse's slider seat is equipped with multiple pressure relief holes, and the upper end of the pressure screw is also provided with an annular pressure relief groove. Both the pressure relief holes and the annular pressure relief groove are used to relieve pressure in the event of accidental ignition and explosion of the flame detonator under explosion-proof conditions, thus improving the fuse's explosion-proof safety. A rectangular ignition channel (shallow groove) is provided in the center of the upper end face of the grenade fuse's slider, ensuring that the delay tube can reliably ignite the flame detonator in the aligned (explosion-proof released) state, and also reliably ignite the flame detonator in the misaligned (explosion-proof released) state. The former is normal ignition when aligned and explosion-proof released, while the latter is an insulated ignition, ensuring the safety of handling unexploded ordnance.

[0009] Compared with the prior art, the significant advantages of the present invention are:

[0010] (1) Fully meet the requirements for non-electric principle fuses in GJB 3194-1998 "Safety Design Guidelines for Manually Deployed Weapons", specifically including explosion protection, redundant safety, delayed release of explosion protection, permissible guided explosives, safety system failure rate, fault protection, human factors engineering (simple structure, robust structure, assembly and setting, manual safety, working status indication), internal energy storage, material compatibility, explosive handling and fireproofing, etc.

[0011] (2) Meets the low-cost requirement. Attached Figure Description

[0012] Figure 1 This is a front cross-sectional view of a high-safety delayed grenade fuse according to the present invention.

[0013] Figure 2 This is a top view of a high-safety delayed-action grenade fuse according to the present invention.

[0014] Figure 3 This is a left cross-sectional view of a high-safety delayed grenade fuse according to the present invention.

[0015] Figure 4 This is a cross-sectional view along section AA of a high-safety delayed grenade fuse according to the present invention.

[0016] Figure 5 This is an isometric view of the fuse body of a high-safety delayed-action grenade fuse according to the present invention.

[0017] Figure 6 This is an isometric view of the slider seat of a high-safety delayed grenade fuse according to the present invention.

[0018] Figure 7 This is a diagram of the cotter pin of a high-safety delayed-action grenade fuse according to the present invention.

[0019] In the diagram, 1 is the fuse body, 2 is the slider seat, 3 is the pressure screw, 4 is the delay tube, 5 is the firing mechanism, 6 is the pull pin safety mechanism, 7 is the grip safety mechanism, 8 is the delayed release explosion-proof mechanism, 9 is the explosion-proof mechanism, 10 is the detonation sequence, 11 is the observation window, 12 is the flapper, 13 is the hammer, 14 is the torsion spring, 15 is the flapper shaft, 16 is the impact cap, 17 is the cap seat, 18 is the cotter pin, 19 is the safety pin pull ring, 20 is the safety pin, and 21 is the slider. 22 is the gripper, 23 is the torsion pin, 24 is the torsion pin pull ring, 25 is the gripper shaft, 26 is the sealing cup, 27 is the sealing spring, 28 is the rubber ring, 29 is the safety rod, 30 is the safety rod spring, 31 is the shape memory alloy safety spring, 32 is the safety pin, 33 is the slider spring, 34 is the flame detonator, 35 is the recovery cylinder, 36 is the recovery cylinder spring, 37 is the detonating cord, 38 is the first detonation tube, 39 is the support tube, 40 is the second detonation tube, and 41 is the convex sight. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] In this embodiment of the invention, all directional indications (such as up, down, left, right, forward, backward, etc.) are only used to interpret specific postures (as shown in the attached diagram). Figure 1 The relative positions and movements of the components (as shown) are such that if the specific posture changes, the directional indication also changes accordingly. Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. The technical solutions of the various embodiments of this invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0022] The following section will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention, using this design example as an example.

[0023] Combination Figures 1 to 7The high-safety delayed grenade fuse of the present invention mainly includes a fuse body 1, a slider seat 2, a pressure screw 3, a delay tube 4, a firing mechanism 5, a pull pin safety mechanism 6, a grip safety mechanism 7, a delayed release explosion-proof mechanism 8, an explosion-proof mechanism 9, a detonation sequence 10, and an observation window 11. The slider seat 2, delay tube 4, delayed release explosion-proof mechanism 8, explosion-proof mechanism 9, detonation sequence 10, partial pull pin safety mechanism 6, and partial grip safety mechanism 7 are arranged in the fuse cavity formed by the fuze body 1 sealed by the pressure screw 3; the firing mechanism 5 is a torsion spring driven flap hammer structure located on the upper part of the fuze body 1; the pull pin safety mechanism 6 and grip safety mechanism 7 form a redundant safety against the explosion-proof mechanism 9, and together with the delayed release explosion-proof mechanism 8 and the explosion-proof mechanism 9, form a safety and release isolation mechanism; the detonation sequence 10 is arranged along the fuze axis, with the upper part being a sensitive linear section, the middle part being a staggered isolation section, and the lower part being a blunt-sensitive linear section; the observation window 11 is located on the outer contour of the middle part of the fuze body 1. The firing mechanism 5 mainly includes the fuze body 1, flap 12, hammer 13, torsion spring 14, flap shaft 15, impact cap 16, and cap seat 17. The flap shaft 15 is located in the horizontal hole on the upper left side of the fuse body 1, used to fix the flap 12 and the torsion spring 14. The hammer 13 is fixed to the flap 12 by riveting or welding. The impact cap 16 is fixed in the cap seat 17 by tapping or spot riveting and screwed into the side threaded hole on the axis of the upper part of the fuse body 1. The grip safety mechanism 7 mainly includes the fuse body 1, the slider seat 2, the grip 22, the torsion pin 23, the torsion pin pull ring 24, the grip shaft 25, the sealing cup 26, the sealing spring 27, the rubber ring 28, the safety rod 29 and the safety rod spring 30. The tip of the safety rod 29 passes through the stepped hole on the upper right side of the fuse body 1 and is inserted into the longitudinal through hole on the right side of the slider seat 2. The safety rod spring 30 is located between the shoulder of the safety rod 29 and the bottom surface of the stepped hole on the right side of the slider seat 2. The torsion pin 23 and the torsion spring 30 are connected to the fuse body 1. The pull pin and pull ring 24 are connected by a flexible collar. The twisted pull pin 23 passes through the reserved hole on the grip 22 and is inserted into the horizontal hole of the left boss of the fuse body 1. The hook at the front end of the grip 22 hooks the grip shaft 25 set on the right cantilever of the fuse body 1. The main body of the grip 22 is close to the outer wall of the projectile, and at the same time, it presses the sealing cup 26 and the sealing spring 27 set in the stepped hole on the upper right side of the fuse body 1, thereby pressing the safety rod 29 below the sealing cup 26 and the rubber ring 28 between the sealing cup 26 and the bottom of the stepped hole. The explosion-proof mechanism 9 mainly includes a fuse body 1, a slider seat 2, a pressure screw 3, a slider 21, a slider spring 33, a flame detonator 34, a recovery cylinder 35, and a recovery cylinder spring 36. The recovery cylinder spring 36 is located inside the recovery cylinder 35 and is also set in the transverse groove on the side of the slider 21. The flame detonator 34 is fixed to the longitudinal stepped hole on the right side of the slider 21 by spot riveting. The slider spring 33 is set in the blind hole at the right end of the slider 21, and its other side abuts against the inner wall of the fuse body 1. The pressure screw 3 is threaded to press the slider seat 2 against the inner cavity of the fuse body 1, forming the moving chamber of the slider 21.The slider 21 is the main explosion-proof component, and the sensitive charge is located in the flame detonator 34, which is in a misaligned explosion-proof state.

[0024] Furthermore, the safety pin 20 of the pull-pin safety mechanism 6 directly locks the slider 21, and both ends of the safety pin 20 are locked by cotter pins 18 and safety pin pull rings 19 respectively, achieving operational safety. To release the safety, the cotter pins 18 must be removed first, and then the safety pin 20 must be pulled out. The grip plate safety mechanism 7's grip plate 22 locks the slider 21 successively through the grip plate shaft 25, the sealing cup 26, and the safety rod 29. The grip plate 22 is locked to the fuse body 1 by the torsion pin 23, achieving operational safety. To release the safety, the torsion pin pull ring 24, which is fitted with the torsion pin 23, is used to first twist the torsion pin 23 and then pull it off the fuse body 1. The pull-pin safety mechanism 6 and the grip plate safety mechanism 7 are independent of each other and do not affect each other. They can both independently achieve the safety of the explosion-proof slider 21, and their release uses different actions, thus meeting the requirements of redundant safety design. With the redundancy and explosion-proof safety requirements met, the flame detonator 34 adopts a closed structure, and both the detonator and the detonating tube are sealed to the outside, thus the failure rate requirement of the fuse safety system can also be met.

[0025] Furthermore, the high-security delayed grenade fuse's pull-pin safety mechanism 6 mainly includes a fuse body 1, a slider seat 2, a cotter pin 18, a safety pin pull ring 19, and a safety pin 20. The safety pin 20 has a first through hole on each side. The first through hole on one side of the safety pin 20 connects to the safety pin pull ring 19, while the other side passes through the radial through hole in the middle of the fuse body 1, through the slider seat 2 and the transverse hole on the slider 21 located in the rectangular groove at the bottom of the slider seat 2, and exits on the other side of the fuse body 1. It is locked by the cotter pin 18 passing through the first through hole on the other side of the safety pin 20, thus realizing an independent safety for the explosion-proof component of the slider 21.

[0026] Furthermore, the delayed-release explosion-proof mechanism 8 of the high-safety delayed-release grenade fuse mainly includes a fuse body 1, a slider seat 2, a delay tube 4, a safety rod 29, a safety rod spring 30, a shape memory alloy safety spring 31, and a safety pin 32. The safety pin 32 is located in the radial through hole in the middle of the slider seat 2. Due to the tension of the shape memory alloy safety spring 31, the left side of the safety pin 32 abuts against the shape memory alloy safety spring 31, and the right mushroom head is inserted into the annular groove of the safety rod 29, thereby restricting the axial movement of the safety rod 29 and thus constraining the slider 21 to ensure explosion-proof safety. When the delay tube 4 is ignited, after a predetermined explosion-proof release delay, such as 1 second, the shape memory alloy safety spring 31 contracts due to heat, allowing the safety pin 32 to retract and move, thereby releasing the safety rod 29. The safety rod 29 is pulled out of the slider 21 under the push of the safety rod spring 30, releasing the slider 21 and realizing the delayed-release explosion-proof function.

[0027] Furthermore, the upper sensitive in-line part of the detonating train 10 of the high-security delay hand grenade fuse includes an impact cap 16 and a delay tube 4; the middle misaligned isolation part is a flame detonator 34; the lower insensitive in-line part includes a detonating tube 37, a first booster tube 38, and a second booster tube 40 arranged in sequence. The impact cap 16 is fixed in the cap seat 17 by crimping or dot riveting and is screwed into the threaded hole on the axis in the upper part of the fuse body 1 together with it; the delay tube 4 is fixed in the delay tube hole on the slider seat 2 below the cap seat 17 by dot riveting; the flame detonator 34 is fixed in the longitudinal stepped hole on the right side of the slider 21 by dot riveting and is misaligned with the delay tube 4 and the detonating tube 38 in the assembled state; the detonating tube 37 is fixed at the upper end of the pressure screw 3 by crimping; the lower end of the pressure screw 3 sequentially fixes the first booster tube 38, the support cylinder 39, and the second booster tube 40 in the bottom blind hole of the pressure screw 3 by crimping. Each explosive element in this detonating train 10 has a single function, high reliability, and is convenient for debugging, development, and quality control. The two-stage booster tube design makes the second booster tube 40 located at the center of the charge, which helps the spatial uniform distribution of the fragments of the projectile body. The detonating tube 28 and the detonating and booster explosives in the two-stage booster tube are selected as the permitted polyblack-14 (JH-14C) detonating explosive.

[0028] Furthermore, the observation window 11 of the high-security delay hand grenade fuse includes the main fuse body 1, the slider seat 2, the slider 3, and the convex peephole 41. On the front of the outer contour of the frustum part of the fuse body 1, slightly to the right and on the right side of the through hole where the safety pin 20 is located, a round hole is additionally opened and communicated with the rectangular groove below the slider seat 2. A convex peephole 41 is installed outside the round hole for observing whether the position of the slider 21 in the inner cavity of the fuse body 1 is in the de-isolated position. Before assembly, it is necessary to first apply a marking with a fluorescent green background and the white Latin letter "S" or the Chinese character "An" printed on it in the middle of the side of the slider 21; apply a marking with a fluorescent red background and the black Latin letter "A" or the Chinese character "Wei" printed on it on the right side of the side of the slider 21. If the marking with a fluorescent green background and the white Latin letter "S" or the Chinese character "An" printed on it is observed through the convex peephole 41 in the observation window 11, it means that the fuse is in the explosion-proof state; if the marking with a fluorescent red background and the black Latin letter "A" or the Chinese character "Wei" printed on it is observed, it means that the fuse has been in the de-explosion-proof state. This is the design of the working state marker required by ergonomics.

[0029] Furthermore, multiple pressure relief holes are provided on the slider seat 2 of the high-security delay hand grenade fuse, and an annular pressure relief groove is also provided at the upper end of the pressure screw 3. The pressure relief holes and the annular pressure relief groove are both used for pressure relief when the flame detonator 34 accidentally ignites and explodes in the explosion-proof state, which helps to improve the explosion-proof safety of the fuse.

[0030] Furthermore, the slider 21 of the high-safety delayed grenade fuse has a rectangular ignition channel (shallow groove) in the middle of its upper surface, ensuring that the delayed tube 4 can reliably ignite the flame detonator 34 in the aligned (disarmed) state, and also reliably ignite the flame detonator 34 in the misaligned (non-disarmed) state. The former is normal ignition when aligned and disarmed, while the latter is an ignition extinguishing mechanism, ensuring the safety of handling unexploded ordnance.

[0031] Furthermore, the safety pin 20 in the pull-pin safety mechanism 6 of the high-safety delayed grenade fuse has a constricted middle structure, meaning the diameter of the middle part that mates with the slider 20 is smaller than that at both ends. Normally, the safety rod 29 positions the slider 20. However, if the safety rod 29 is misinstalled, missing, or broken, or if a component of the lever safety mechanism 7 fails, causing the safety rod 29 to accidentally disengage from the slider 21 and lose its positioning function, the slider 21, pushed by the slider spring 33, engages with the constricted neck of the safety pin 20 through its transverse opening. The fuse then enters a fail-safe state, and the safety pin 20 is locked by the slider 21 and can no longer be normally withdrawn. This is the fail-safe characteristic of the fuse. This characteristic also solves the problem that the slider spring 33, as an internal energy storage device, would reduce the fuse's safety.

[0032] Furthermore, the high-safety delayed-action grenade fuse comprises 34 components, including 26 self-made parts, 2 standard parts, and 6 explosive elements. The 2 standard parts are cotter pin 18 and rubber ring 28, while the 6 explosive elements are impact cap 16, delay tube 4, flame detonator 34, detonating cord 37, first detonating tube 38, and second detonating tube 40. Except for the fuse body 1, slider seat 2, slider 21, and gripper 22, almost all self-made parts are of rotational shape, ensuring good manufacturability. The gripper 22 is manufactured using a stamping process, while the fuse body 1, slider seat 2, and slider 21 can be manufactured using efficient and low-cost molding processes such as die casting, extrusion, and injection molding. Except for shape memory alloys, the materials used in the fuse are all commonly used materials with good compatibility, and the shape memory alloys are estimated to be incompatible with other materials as well. The fuse structure has sufficient design margins in terms of strength and stiffness. Therefore, it can be considered that the high-safety delayed grenade fuse meets the requirements of material compatibility, as well as the requirements of simple and robust human factors engineering structure.

[0033] Furthermore, the high-safety delayed-action grenade fuse design ensures that it will not be assembled into a disarmed state or have its safety reduced. The specific principle is as follows: If the slider 21 is missing, it will be discovered during the tightening of the pressure screw 3 during assembly. If it is not discovered, it can be detected during subsequent finished product inspection through the observation window 11 and by weighing, and then rejected. If the upper and lower surfaces of the slider 21 are installed backwards, it will not reduce safety, but will only affect reliability: detonation transmission will be unreliable. If the left and right positions of the slider 21 are installed backwards, it will not reduce safety, but will only affect reliability (the anti-recovery mechanism will fail). If the slider 21 is already in the aligned, disarmed position, the safety pin 20 and safety rod 29 cannot be properly assembled, and the fuse cannot complete subsequent assembly, resulting in an incomplete fuse. The high-safety delayed-action grenade fuse does not involve setting. Therefore, it can be considered that the high-safety delayed-action grenade fuse meets the requirements for human factors engineering assembly and setting.

[0034] Furthermore, the manual safety components of the high-security delayed grenade fuse, namely the torsion pin 23 and the cotter pin 18, are both mature technologies. There is no possibility of accidental or erroneous operation that could disarm them, and the safety can be restored when needed. In other words, the manual disarming operation is reversible, which meets the human factors engineering requirements for manual safety components.

[0035] The challenge of this invention lies in achieving a simple, compact, and low-cost fuse structure, while fully meeting the requirements of GJB3194-1998 "Safety Design Guidelines for Manually Deployed Weapons" for non-electric fuses, namely explosion-proof, redundant safety, delayed explosion-proof release, permissible guided explosives, safety system failure rate, fault tolerance, human factors engineering (simple structure, robust structure, assembly and setting, manual safety components, working status indication), internal energy storage, material compatibility, explosive disposal, and fireproofing.

[0036] The working principle of the high-safety delayed-action grenade fuse of this invention is as follows:

[0037] Normally, the fuze is in its factory-assembled state, i.e., the explosion-proof safety state. The cotter pin 18, safety pin 20, and torsion pin 23 are all in place. The pull-pin safety mechanism 6 and the grip safety mechanism 7 form a redundant safety system, locking the main explosion-proof component, the slider 21, along with the flame detonator 34 inside, in a misaligned explosion-proof state. Reliable drops, vibrations, shocks, and impacts cannot accidentally disarm the fuze, meaning the fuze remains in its factory-assembled state. Even if the flame detonator 34 accidentally ignites and explodes, it will not detonate the detonating cord 37, the first detonating tube 38, or the second detonating tube 40. The pressure relief cavities within the slider 21, slider seat 2, and pressure screw 3 effectively absorb the energy released by the accidental explosion of the flame detonator 34 in the misaligned explosion-proof position, thereby improving the fuze's explosion-proof safety.

[0038] During normal use, when preparing for throwing, first pull out the split pin 18, and then use the pull ring 19 of the safety pin to pull out the safety pin 20 to release the first-stage safety. Before throwing, while ensuring that the grip piece 22 can always be firmly held, remove the twist-pull pin 23. After the grenade is thrown, under the redundant action of the pre-pressure exerted by the sealing spring 27 and the torsion spring 14 on the flap 12, the centrifugal force generated by the possible rotation of the grenade, and the air resistance against the oncoming flight of the grenade, the grip piece 22 of the grenade separates from the fuse body in the air. The flap 12 rotates around the flap shaft 15 to above the fuse body 1, causing the striker 13 to strike the percussion cap 16. The percussion cap 16 ignites and then ignites the delay tube 4. After the delay tube 4 burns for a period of time, the heat it outputs causes the shape memory alloy safety spring 31 to contract, releasing the restriction of the safety pin 32 on the safety lever 29; the safety lever spring 30 pushes the safety lever 29 to eject the sealing cup 26, and at the same time releases the restriction of the safety lever 29 on the slider 21; the slider spring 33 pushes the slider 21 to move left until the upper side of the flame detonator 34 in the slider 21 is aligned with the delay tube 4 and the lower side is aligned with the detonator tube 37, and the fuse is de-isolated. At this time, the anti-recovery cylinder 35 is pushed by the anti-recovery cylinder spring 36 into the semi-cylindrical deep groove on the side of the rectangular groove under the slider seat 2, and the fuse enters the anti-recovery state after de-isolation. After that, the delay tube 4 further burns, and after a certain delay, it ignites the flame detonator 34. The flame detonator 34 detonates the detonator tube 37, and then detonates the first booster tube 38 and the second booster tube 40 in sequence, and then detonates the explosive charge in the grenade body. This is normal ignition. In addition to this situation, since a rectangular fire transfer channel (shallow groove) is provided in the middle of the upper end face of the slider 21, it can ensure that the delay tube 4 can reliably ignite the flame detonator 34 in the misaligned state, that is, the non-de-isolated state. Therefore, even if the fuse is not de-isolated, that is, the slider 21 is not aligned, the fuse will change from normal ignition to misfire.

[0039] When it is necessary to determine the state of the fuse, it can be completed by observing the working state marker set on the fuse. That is, observe through the convex peephole 41 in the observation window 11. If it is observed that the color on the side of the slider 21 is fluorescent green and there is a white Latin letter "S" or a Chinese character "An" marked on it, it means that the slider 21 is in the initial position and the fuse is in the explosion-proof state; if it is observed that the color on the side of the slider 21 is fluorescent red and there is a black Latin letter "A" or a Chinese character "Wei" marked on it, it means that the slider 21 has completed the de-isolation movement and the fuse has been de-isolated.

[0040] After the start of preparing for throwing and the pull-pin safety mechanism 6 is de-safed, if it is decided to abort the subsequent throwing, the removed safety pin 20 and the removed split pin 18 can be reset to restore the pull-pin safety mechanism 6 of the fuse to the factory state, that is, the safe state. If the grip-piece safety mechanism 7 has also been de-safed, in order to prevent danger from occurring accidentally during subsequent operations and use, it is recommended to throw the fuse and the equipped grenade as far as possible and not perform the operation of restoring the safety.

[0041] If a thrown grenade fails to explode and unexploded ordnance (UFO) disposal is required, the presence of smoke inside and outside the fuze, and whether the explosion-proof barrier has been disarmed, can be observed through the safety hole and observation window 11 on the side of the outer contour of the fuze body 1. The status of the firing mechanism 5 and the percussion cap 16 can also be observed to determine whether they have been fired and whether they have ignited, thus determining whether the fuze is in a dormant or safe misfire state. This result guides subsequent UFO disposal work. Only when the percussion cap 16 fails to ignite and the slider 21 is in a disarmed state is it considered a dangerous misfire state. All other states are either dormant or safe misfire states, ensuring safe UFO disposal. Since the hammer-impact percussion cap firing mechanism 6 is difficult to re-ignite during subsequent UFO disposal, combined with the aforementioned dormant characteristic, the grenade fuze of this invention has good UFO safety disposal characteristics.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-safety delayed-release grenade fuse, comprising a fuse body (1), a slider seat (2), a pressure screw (3), a firing mechanism (5), a delay tube (4), a pull pin safety mechanism (6), a grip safety mechanism (7), a delayed-release explosion-proof mechanism (8), an explosion-proof mechanism (9), a detonation sequence (10), and an observation window (11), characterized in that: The slider seat (2), the delay tube (4), the delay de-ignition isolation mechanism (8), the ignition isolation mechanism (9), the transmission sequence (10), the partial pull pin safety mechanism (6) and the partial grip piece safety mechanism (7) are arranged in the inner cavity of the fuze body (1) which is sealed by the pressure screw (3); the firing mechanism (5) is a flip hammer type structure driven by a torsion spring and is located at the upper part of the fuze body (1); the pull pin safety mechanism (6) and the grip piece safety mechanism (7) constitute a redundant safety for the ignition isolation mechanism (9) and form a safety and de-isolation mechanism together with the delay de-ignition isolation mechanism (8) and the ignition isolation mechanism (9); the transmission sequence (10) is arranged along the fuze axis and has a sensitive straight sequence part at the upper part, a staggered isolation part at the middle part and a blunt straight sequence part at the lower part; the observation window (11) is arranged on the outer contour of the middle part of the fuze body (1); A plurality of pressure relief holes are arranged on the slider seat (2) and an annular pressure relief groove is further arranged on the upper end of the pressure screw (3); The pull pin safety mechanism (6) comprises a split pin (18), a safety pin pull ring (19) and a safety pin (20), a first through hole is formed on each side of the safety pin (20), the first through hole on one side of the safety pin (20) is connected with the safety pin pull ring (19), the first through hole on the other side passes through the slider seat (2) and the transverse hole on the slider (21) located in the rectangular groove at the bottom of the slider seat (2) along the radial through hole of the middle part of the fuze body (1), and the slider (21) is locked by the split pin (18) passing through the first through hole on the other side of the safety pin (20) to realize one independent safety of the ignition isolation of the slider (21); The delay de-ignition isolation mechanism (8) comprises a safety lever (29), a safety lever spring (30), a memory alloy safety spring (31) and a safety pin (32); the safety pin (32) is located in the radial through hole of the middle part of the slider seat (2), the left side of the safety pin (32) is abutted against the memory alloy safety spring (31) due to the tension of the memory alloy safety spring (31), and the mushroom head of the right side is clamped into the annular groove of the safety lever (29) to realize the axial movement limitation of the safety lever (29) and further restrict the slider (21) to ensure the ignition safety; A rectangular transmission channel is arranged on the middle part of the upper end surface of the slider (21); The middle part of the safety pin (20) in the pull pin safety mechanism (6) is a necked structure, that is, the diameter of the middle part matched with the slider (21) is smaller than that of the two ends.

2. The high safety delay grenade fuze according to claim 1, characterized in that: When the delay tube (4) is ignited, after a predetermined de-ignition delay, the memory alloy safety spring (31) is contracted by heat, the safety pin (32) can be retracted and moved, thereby releasing the safety lever (29), the safety lever (29) is pulled out from the slider (21) under the pushing of the safety lever spring (30), the slider (21) is released, and the delay de-ignition function is realized.

3. The high safety delay grenade fuze according to claim 2, characterized in that: The upper sensitive straight-line part of the booster train (10) comprises an impact cap (16) and a delay tube (4); the middle staggered isolation part is a flame tube (34); the lower insensitive straight-line part comprises a booster tube (37), a first booster tube (38) and a second booster tube (40) arranged in sequence; the impact cap (16) is fixed in the cap seat (17) by crimping or spot welding and is screwed into the threaded hole on the upper part of the fuse body (1) on the axis; the delay tube (4) is fixed in the delay tube hole on the slider seat (2) below the cap seat (17) by spot welding; the flame tube (34) is fixed in the right longitudinal stepped hole of the slider (21) by spot welding and is staggered with the delay tube (4) and the booster tube (37) in the assembled state; the booster tube (37) is fixed on the upper end of the press screw (3) by crimping; the press screw (3) fixes the first booster tube (38), the supporting cylinder (39) and the second booster tube (40) in the blind hole at the bottom of the press screw (3) by crimping in sequence.

4. The high safety delay grenade fuze according to claim 3, characterized in that: The observation window (11) comprises a convex mirror (41); a circular hole is formed on the right side of the through hole of the safety pin (20) on the front surface of the outer contour of the circular cone part of the fuse body (1), which is communicated with the rectangular slot below the slider seat (2), and the convex mirror (41) is installed on the outside of the circular hole for observing whether the position of the slider (21) in the inner cavity of the fuse body (1) is in the disarmed position; before assembly, the slider (21) side surface is marked with a white Latin letter "S" or Chinese character "An" in fluorescent green on the bottom and a black Latin letter "A" or Chinese character "Danger" in fluorescent red on the top; through the convex mirror (41) in the observation window (11), if the mark of the white Latin letter "S" or Chinese character "An" in fluorescent green is observed, it indicates that the fuse is in the explosion-proof state; if the mark of the black Latin letter "A" or Chinese character "Danger" in fluorescent red is observed, it indicates that the fuse has been in the disarmed state.

5. The high safety time delay grenade fuze according to claim 4, wherein: The pressure relief hole and the annular pressure relief groove are used for pressure relief after the accidental firing and explosion of the flame tube (34) in the explosion-proof state, which helps to improve the explosion-proof safety of the fuse.

6. A high safety time delay grenade fuze according to claim 5, wherein: The rectangular fire transmission channel ensures that the delay tube (4) can reliably ignite the flame tube (34) in the aligned disarmed state and the flame tube (34) in the staggered non-disarmed state, wherein the former case is the normal firing of the aligned disarmed state, and the latter case is the dead fire, which can ensure the safety of the explosive material handling of unexploded ammunition.

7. A high safety time delay grenade fuze according to claim 6, characterized in that: Under normal circumstances, the slider (21) is positioned by the safety lever (29); when the safety lever (29) is incorrectly installed, missing, broken or has other conditions that cause the positioning of the safety lever (29) to fail, the slider (21) is pushed by the slider spring (33) to have its slider orifice clamped into the necked part of the safety pin (20), and the fuse enters the fault safety state, after which the safety pin (20) is locked by the slider (21) and cannot be normally pulled out.

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