The 50-Caliber Dearmer

One technique for rendering an explosive ordnance device safe is to dearm that device by rendering its fuze mechanis inoperative. This can be accomplished by destroying or damaging that fuze mechanism so the firing pin thereof will not be able to contact the detonator device. In this manner, the detonator will not be able to set off the warhead of the ordnance device. Dearming an explosive ordnance in this manner requires propulsion of a fuze destroying device against the fuze with enough power to sufficiently damage the fuze to render it inoperative. This result is generally accomplished by firing a slug from a tube aimed at the fuze with enough velocity to impact a portion of the fuze extending out over the ordnance case. This impact bends the whole fuze body making firing pin movement impossible, or in some cases, actually decapitating a portion of the ordnance item. The dearming device therefore includes tube with an propellant charge and a plug housed therein. The propellant charge is set off by a primer and propels the slug out of the tube at a velocity characteristic of that propellant charge.

Currently available dearmers are designed to be reusable. Accordingly, these

dearmers use available propellant charges and are assembled by the operator

at the use site. This design has several drawbacks. First, assembly at the use

site requires the operator to work in the vicinity of an unexploded ordnance device,

which in and of itself is undesirable. Second, using propellant charges requires

using a charge that is adequate for the largest ordnance device in order to be of

universal application. This, in turn, causes the propellant charge to be too large

for most applications. Not only is this uneconomical, it causes problems in

aiming the dearmer, as a large charge may produce a kick-back after firing

of the dearmer thereby affecting the aiming of that dearmer. It is desirable to avoid the kick-back problem if possible. Accordingly, currently available dearmers are difficult to set-up and aim. Heavy weighting equipment may be necessary to absorb the kick-back and this makes of even more difficult to set up and aim the dearmer. As the charges are usually quite large, the dearmer must be heavy to accommodate the charge. This makes the dearmer bulky and difficult to transport. Presently, only one, and no more than two, dearmers can be carried by one EOD technician. After setting up one or two units, the EOD technician must return for additional slugs and cartridges thereby creating logistics a problem.

A further problem with using currently available propellant dearmer is that they are generally not protected against stray electromagnetic or electrostatic energy. These charges are therefore susceptible to inadvertent detonation. Yet another problem with currently available dearmers is the cost of manufacturing them. Every time a dearmer is used, there may be damage to the tube due to the set back impact collisions. Heretofore, it has been assumed that the internal bore of these tubes must be extremely smooth in order to properly aim the slug. Thus, the reusable dearmer must be carefully maintained thereby making them expensive to manufacture and maintain.

These and other objects are accomplished by a disposable EOD dearmer which includes an propellant charge mounted in a tube adjacent to a slug. The propellant charge is designed to produce a specially selected pressure versus time characteristic in order to propel the slug with a velocity which is predetermiend to be necessary for dearming a particular ordnance device with which the dearmer will be used. In this manner, the dearmer need not be larger and more powerful than necessary. Being disposable, the dearmer can be completely self-contained and can be manufactured as economically as possible. This advantage alleviates the aforementioned logistics and set-up problems for the EOD technician and also reduces the overall cost of these units.