Anti-handling device
An anti-handling device is an attachment to or an integral part of a
Purpose
Anti-handling devices prevent the capture and reuse of the munition by enemy forces. They also hinder
Anti-handling devices greatly increase the danger of munitions to civilian populations in the areas in which they are used because their mechanisms are so easily triggered. An anti-tank mine with an anti-handling device fitted is almost guaranteed to detonate if it is lifted/overturned, because it is specifically designed to do so. Munitions fitted with anti-handling devices increase the difficulty and cost of post-conflict clearing operations, due to the inherent dangers of attempting to render them safe.
Not all munitions will have an anti-handling device. Perhaps one in ten antitank mines in a large defensive minefield will have boobytrap firing devices screwed into their secondary fuze wells. Even so, deminers and explosive ordnance disposal (EOD) personnel are forced to assume that all items they encounter may have been boobytrapped, and must therefore take extra precautions. This has the effect of significantly slowing down the clearance process.
History
Anti-handling mechanisms have been used in fuzes since at least 1940, for example, in
ZUS-40s were designed to fit underneath most Luftwaffe bomb fuzes. When a delayed-action bomb containing a ZUS-40 was dropped on a target, the impact when it hit the ground freed a ball-bearing inside the ZUS-40, thereby arming a
Some German anti-handling fuzes were even more dangerous to EOD personnel, such as the type 50 and 50BY fuzes. These were normally fitted to 250/500 kg bombs and contained two
Allied forces developed their own designs of anti-handling devices during World War II. For example, the American M123A1,[8] M124A1, M125 and M131 series of chemical long delay tail-fuzes which were used in air-dropped bombs, starting around late 1942 and remaining in service until the 1960s. Frequently fitted to M30 (100 lb), M57 (250 lb) M64 (500 lb), M65 (1000 lb) and M66 (2000 lb) general-purpose bombs, these fuzes were primarily designed to operate as chemical long-delay fuzes, with the following delay times: 1, 2, 6, 12, 24, 36, 72, and 144 hours.[9] The time delay mechanism was simple but effective: after being dropped from the aircraft a small propeller at the rear of the bomb revolved, gradually screwing a metal rod into the fuze, crushing an ampoule inside it, which contained a solution of alcohol and acetone solvent. When this happened the fuze was fully armed and the timer countdown had started. The alcohol-acetone solution soaked into an absorbent pad next to a celluloid disk which held back a spring-loaded firing pin from a percussion cap connected to an adjacent detonator. Acetone slowly dissolved the celluloid disk, gradually weakening it until the cocked firing pin was released and the bomb detonated.[10] The time delay of the fuze varied according to the acetone concentration and the thickness of the celluloid disk. Removing a chemical long delay fuze from a bomb after it had been dropped would have been a straightforward process had it not been for the fact that there was an integral anti-withdrawal mechanism designed to kill anyone who tried to render the bomb safe. Fuzes such as the M123 (and its derivatives) contained two small ball-bearings at the lower end which slid out of recesses when the fuze was screwed into the bomb by aircraft armorers.[11][12] The ball-bearings jammed into the screw-threads inside the fuze well, preventing the fuze from being removed. Because the lower end of the fuze was locked in place deep inside the bomb (where access was difficult) this posed major problems for enemy EOD personnel. Attempting to unscrew a fully armed chemical long-delay fuze caused it to split into two separate fuze assemblies. This action automatically triggered detonation by releasing the cocked firing pin in the lower fuze assembly, with lethal results for anyone nearby.[13] In addition to their undoubted value in harassing the enemy, another tactical use of these chemical long delay fuzes was during the first wave of a bombing attack, when most (and occasionally all) of the ordnance dropped on the target would have chemical long delay fuzes fitted, with various time delays. The second wave of bombers arriving a few minutes later would not face problems in identifying targets due to them being obscured by smoke and dust from previous explosions, and therefore could accurately drop bombs with instantaneous fuzes fitted. Meanwhile, the bombs dropped by the first attack wave had already hit their targets and the count-down to detonation was in progress.[14]
The British "Number 37 Long Delay Pistol" (used by RAF Bomber Command during World War II) was another chemical long delay fuze which used a similar type of anti-removal mechanism. A later design of British nose fuze called the number 845 Mk 2 operated purely in anti-disturbance mode. It contained a mercury switch which triggered detonation if the bomb was moved after a 20-second arming delay, which started when the bomb hit the ground.[20]
Since then, many nations have produced a wide variety of munitions with fuzes which incorporate some form of anti-handling function, including very small weapons such as
Classes
US Army field manual FM 20–32 classifies four classes of anti-handling devices:
- Anti-lifting devices. A device which initiates an explosion when a protected mine is lifted or pulled out of its hole.
- Anti-disturbance device. A device which initiates an explosion when a protected mine is lifted, tilted or disturbed in any way e.g. a notable variant of the VS-50 mine featuring an integral mercury switch.
- Anti-defuzing device. A device which initiates an explosion when an attempt is made to remove a fuze from a protected mine.
- Anti-disarming device. A device which initiates an explosion when an attempt is made to set the arming mechanism of a mine to safe.
Types of anti-handling fuzes
The different classes of anti-handling devices are normally created using a variety of fuzes. This is a list of the types of fuzes used as anti-handling devices:
- Pull fuzes — these are typically installed in secondary fuze wells located on the side or bottom of landmines. The fuze is normally connected to a thin wire attached to the ground, so the wire is automatically pulled if the mine is lifted, shifted or disturbed in any way. Simple pull-fuzes release a spring-loaded striker. More sophisticated versions are electronic i.e. feature a break-wire sensor which detects a drop in voltage. Either way, pulling on the hidden wire triggers detonation.
- Anti-lifting fuzes — these are frequently screwed into an auxiliary fuze pocket located underneath anti-tank landmines. The act of lifting or shifting the mine releases a cocked striker, triggering detonation. The M5 universal firing device is a classic example of an anti-lift fuze. Its standard gauge screw thread allows it to be fitted to various munition types, ranging from an M26 hand grenade up to an M15 antitank landmine.[24]
- Tilt/vibration switches — this is a fuze installed inside the device which triggers detonation if the sensor is tilted beyond a certain angle or is subject to any vibration. Typically, some form of pendulum arrangement, spring-loaded "trembler" or mercury switch is used to detect this.
- Anti-mine detector fuzes — developed during World War II to detect the magnetic field of mine detectors.
- Electronic light sensitive, thermal or acoustic sensitive. Potentially, such fuzes can discriminate between various types of mine clearance operations i.e. resist activation by devices such as mine flails, plows, or explosives, whilst still detonating when handled by demining personnel. Additionally, electronic fuzes may have an inbuilt self-destruct capability i.e. some form of timer countdown designed to trigger detonation hours, days or even months after deployment, possibly whilst people are attempting to render the device safe. Although fuzes with a self-destruct capability are not anti-handling devices per se, they do add an extra complicating factor to the bomb disposalprocess.
See also
References
- ^ Lockhart, Greg (4 June 2007). "The Minefield: An Australian Tragedy in America's Vietnam War". The Asia-Pacific Journal. 5 (6). Retrieved 23 February 2015.
- ^ The Handbook Of The SAS And Elite Forces. How The Professionals Fight And Win. Edited by Jon E. Lewis. p.351-Tactics And Techniques, Personal Skills And Techniques. Robinson Publishing Ltd 1997. ISBN 1-85487-675-9
- ^ "ZUS 40 (Anti withdrawal device 40) Germany WW2". British Ordnance Collectors Network. January 2008. Retrieved 22 July 2011.
- WalesOnline. Retrieved 22 July 2011.
- ISSN 0161-7370. Retrieved 22 July 2011.
- ^ Peverelli, Lex. "T.Mi.Z.43". Grenades, Mines and Boobytraps. Archived from the original on 2016-03-04. Retrieved 23 February 2015.
- ^ Don't Get Killed by Mines and Booby Traps (War Department Pamphlet No. 21–23) (PDF). Washington DC: U.S. War Department. 17 November 1944. Archived from the original (PDF) on 2008-06-27. Retrieved 2015-06-09 – via Grenades, Mines and Boobytraps.
- ^ U.S. Explosive Ordnance. Bureau of Ordnance. 28 May 1947. pp. 487–489. Retrieved 23 February 2015 – via Maritime Park Association.
- ^ "OP 1664 - U.S. Explosive Ordnance (Vol. 2); Part 6 - Bombs and Bomb Fuzes; Chapter 20 - Bomb Fuzes; Section 2 - Army-Designed Bomb Fuzes: M123, M124, and M125 (Obsolescent) (Tail Chemical Time, Anti-Withdrawal)".
- Spiegel Online. Retrieved 23 February 2015.
- ^ "US M124A1 Tail Fuze". British Ordnance Collectors Network. 29 December 2011. Retrieved 23 February 2015.
- ^ "US M123 Tail Fuze". UXO Info. Archived from the original on 1 November 2014. Retrieved 1 April 2012.
- ^ EOD987654321. "Introduction to US Bomb Fuzes". Scribd. Retrieved 22 July 2011.
{{cite web}}
: CS1 maint: numeric names: authors list (link) - ^ "There Are Still Thousands of Tons of Unexploded Bombs in Germany, Left over from World War II".
- ^ "Routine Disposal Goes Wrong: Three Killed in Explosion of World War II Bomb in Germany". Spiegel Online. 2 June 2010. Retrieved 23 February 2015.
- ^ "WWII bomb kills three in Germany". BBC News. 2 June 2010.
- ^ "Three dead as Second World War bomb explodes in Germany". The Daily Telegraph. 2 June 2010. Retrieved 23 February 2015.
- ^ "Bomb kills German explosive experts". The Daily Express. Retrieved 23 February 2015.
- ^ "Munich police detonates second world war bomb – video". The Guardian. 29 August 2012. Retrieved 23 February 2015.
- ^ "Nose Fuze No. 845". British Ordnance Collectors Network. June 2007. Retrieved 22 July 2011.
- ^ "GRC/AR Delay Tail Fuze". Mil-Spec Industries Corp. 2010.[permanent dead link]
- ^ TM E9 1984 Disposal Methods for Enemy Bombs & Fuzes. Washington DC: U.S. War Department. 12 November 1942. Retrieved 23 February 2015 – via Scribd.
- ^ "Antivehicle Mines With Antihandling Devices". Landmine and Cluster Munition Monitor. Cluster Munition Coalition. Retrieved 23 February 2015.
- ^ Peverelli, Lex. "Release firing device M5". Grenades, Mines and Boobytraps. Archived from the original on 2011-07-23. Retrieved 22 July 2011.
External links
- Fitting External Anti-Handling Devices to Anti-Tank Landmines
- MVE-NS mine fuze (anti-handling device)
- Russian MC-2 pressure-release antihandling device (circa 1940s) contains 200g explosives and can be used as standalone boobytrap
- Russian MC-3 pressure-release antihandling device (circa 1970s), frequently emplaced under the TM-46, |TM-62 and similar anti-tank landmines. It contains 200g explosives and can also be used as standalone boobytrap[permanent dead link]
- Russian ML-7 pressure-release antihandling device (circa 1984) contains 40g explosives and can also be used as standalone boobytrap
- Russian ML-8 antihandling device (circa 1980s) contains 80g explosive and can be also used as standalone boobytrap
- [1]
- [2]
- [3]