Ordnance – Mine-destroying devices
Reexamination Certificate
2001-07-25
2002-11-19
Eldred, J. Woodrow (Department: 3644)
Ordnance
Mine-destroying devices
C083S928000, C083S663000, C083S673000, C083S675000
Reexamination Certificate
active
06481326
ABSTRACT:
This invention concerns a cutting assembly and to related apparatuses such as a vehicle having such a cutting assembly mounted thereon. Such apparatuses are useful in the clearance of landmines and other unexploded ordnance.
As used herein the term “ordnance” includes, but is not limited to, landmines, fragments of landmines, shells and fragments thereof, detonators, grenades and rockets.
Clearance of ordnance in general, and landmines in particular, is a subject that affects the lives of millions of people worldwide. It is well known that armies commonly lay thousands of mines at a time. This creates lethal minefields that often affect civilians more than they affect military personnel. The minefields usually remain highly hazardous to pedestrians and vehicles long after the cessation of armed conflict in an area.
The clearance of ordnance is a laborious process that presents serious risks to the individuals involved in it. The most commonly practised method of landmine clearance requires a pedestrian, protected by little more than a helmet and an armoured vest, repeatedly to prod at the ground with a rigid stick that is intended to locate unexploded ordnance by feel.
Aside from the risk of the individual accidentally treading on a mine during the clearance operation, this method is often unreliable for various reasons. These include that of variations in the depths to which the stick is inserted into the ground; and that the small contact area of the end of the stick, that is necessary for easy insertion of the stick into the ground, makes it easy to miss ordnance and leave it, unexploded, in the ground. Also, this method is difficult to practise in frozen ground. Freezing of the ground often hampers landmine clearance in the states formerly known as Yugoslavia, for example.
Patent application number EP-A-0 842 388 discloses an apparatus for detonating landmines.
The apparatus of EP-A-0 842 388 is highly effective in detonating landmines reliably and safely, but detonation alone does not render modern minefields safe. This is because the device of EP-A-0 842 388fails to detonate some mines, as a result of faults in the mines or the presence of unremoved safety devices; and some unexploded ordnance, hand grenades, mortars, shells, rockets, etc. Such devices are liable to cause death and injury to people who come into contact with them.
Many modern designs of landmine (such as anti-personnel mines manufactured from plastics materials) are intended to fragment on detonation into pieces that are perhaps 10%-50% of the size of an intact mine. It is known to use a flail machine, as an alternative to the apparatus of EP-A-0 842 888, for detonating ordnance. Sometimes the flail machine may fragment a mine without detonating it. This leads to the presence of comparatively large mine fragments, connected to operational detonators, in minefields supposedly rendered safe by the flail machine. Such pieces of landmine are highly explosive and remain capable of causing severe injuries to people who tread on or otherwise contact them.
Consequently the United Nations (UN), who have responsibility for many landmine clearance operations, have specified a requirement that clearance processes must be capable of reliably clearing all ordnance from contaminated areas. The UN have also specified that clearance should taken place to a depth of 25 cm where appropriate. However, there are certain areas, in the Falkland Islands for instance, where it may be necessary to clear to depths up to 50 cm.
It is thought desirable that landmine clearance processes must be capable of reliably reducing the size of each piece of ordnance, remaining in or on the ground after a clearance operation, to a maximum diameter of 10 mm. This ensures destruction of known detonators, for example.
Care needs to be taken during clearance that the topsoil and subsoils are not compacted or mixed in such a manner that the land is rendered infertile. This would cause hardship in the communities that landmine clearance is intended to benefit. In general landmines do not, naturally, sink below the topsoil. The depth of necessary clearance will however vary from one extreme, such as a rocky surface, to another, such as a peaty area in the Falkland Islands.
Thus it would be desirable to provide an apparatus for reliably removing and rendering safe all pieces of landmine in a minefield, regardless of their size and location, and regardless of the soil type.
According to a first aspect of the invention, there is provided a cutting assembly comprising a rotatable shaft supporting one or more elongate, arcuate blades, the or each blade having a base portion and a terminal portion remote from the base portion, the terminal portion being narrower than the base portion, the blade tapering in at least one plane between the base and terminal portions, a first, arcuate edge of the blade, extending between the base and terminal portions, being sharpened and the terminal portion including a second, sharpened edge, the or each blade protruding from the shaft with its terminal portion remote from the shaft and arranged so that the first edge of the or each blade is a leading edge when the shaft rotates in a predetermined direction, and the second sharpened edge trails the first edge during such rotation.
This arrangement may be lain on or inserted into the soil of a minefield or battle area and driven forwardly eg. by means of a pushing or pulling vehicle. Rotation of the shaft causes the first sharpened edge of the or each blade to cut through soil and eg. tree and plant roots, tripwires and cables, thereby freeing any unexploded ordnance such as mines. The trailing, second edge and the arcuate shape of the or each blade then lift such fragments, and other solid objects, to the surface of the minefield, from where they can readily be removed and destroyed or otherwise rendered harmless.
The action of bringing large fragments to the surface is also advantageous when the ground contains very large items of unexploded ordnance, such as complete mines. Such ordnance could damage the cutting assembly. The action of bringing such ordnance to the solid surface makes it visible, thereby permitting rendering the ordnance harmless in a controlled manner.
In preferred embodiments the first, sharpened edge (ie. the leading edge during use of the apparatus) is convexly curved. This assists in bringing solid matter to the surface of the minefield, without subsequently burying it again.
Preferably the cutting assembly includes a drive transferring means for imparting rotational motion to the shaft. Conveniently the assembly includes a support, for the rotatable shaft, that co-acts with one or more said first edges to sever scissile material carried on a said blade during rotation of the shaft. These arrangements allow the cutting assembly to cut through thick and/or tough members such as detonator wires, tripwires and plant matter such as branches and roots.
In preferred embodiments the cutting assembly includes a conveyor disposed adjacent the rotatable shaft and arranged to convey matter from a first location, adjacent the rotatable shaft, to a further location, remote from the rotatable shaft This feature permits the removal, from the vicinity of the shaft and blade(s), of unexploded ordnance, such as landmine fragments, and other solid matter that could cause injury in the event of an explosion nearby. Once removed from the vicinity of the rotatable shaft, the ordnance and other solid matter can be separated from one another and the ordnance rendered harmless.
Conveniently the conveyor is a bucket conveyor including a moveable belt having mounted thereon one or more conveying buckets. It is also preferable that the moveable belt is located and dimensioned so as to permit the or each conveying bucket when at the first location to receive matter cut by the said blade or blades on the shaft, and convey such matter to the further location.
In preferred embodiments the moveable belt is endless and is driven to move the or each conveying bucket between the first
Eldred J. Woodrow
Fish & Richardson P.C.
J R French Limited
LandOfFree
Cutting assembly and related apparatuses does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cutting assembly and related apparatuses, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cutting assembly and related apparatuses will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2979946