Ammunition and explosives – Blasting – Terrain clearance
Reexamination Certificate
1999-12-17
2001-08-28
Jordan, Charles T. (Department: 3641)
Ammunition and explosives
Blasting
Terrain clearance
C102S301000, C089S001100
Reexamination Certificate
active
06279481
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns a device for provoking the collapse of a snow cornice, said device comprising at least one gas exploder.
BACKGROUND OF THE INVENTION
Devices which provoke the collapse of snow cornices are known in the art, consisting of a gas gun attached to the side of a mountain with its base solidly anchored in a seating consisting of a concrete block and its mouth opening above the snow cover, such as described in U.S. Pat. No. 5,107,765. These guns are designed to provoke avalanches in exposed areas, for example, above ski stations or inhabited areas. The devices are very effective in provoking avalanches in zones known as avalanche corridors, that is, areas consisting primarily of steeply sloped gorges where snow accumulates rapidly and may attain unstable critical masses. They have proven particularly effective on light snow that is not dense and has a high volume of air trapped inside the snow crystals. The movement triggered by detonation provokes a wave effect with strong initial compression, followed by a slower movement that breaks up the snow cover and raises the mass of snow enough to provoke an avalanche. However, in areas where a thick crust is forming rapidly, the action of the explosion above the stabilized, dense snow layer and the shock wave propagated in the air are not sufficient to break the snow cover and trigger an avalanche.
Furthermore, these devices need to be anchored rigidly and very solidly to a mountain side, specifically, by means of a concrete seating anchored to rock. It may be difficult to position such a base on a steep area, or where there is limited access or crumbling rock. This is the often the case along cornices where snow may accumulate on an outcropping and where the rocky base is not always suitable for supporting a reinforced concrete seating for an avalanche-provoking gun as defined above. Moreover, cornices may be quite long and the crest, which defines the extent of snow movement in avalanches, may stretch for dozens or even hundreds of meters. In this case it would be necessary to install several guns in order to effectively provoke an avalanche, thereby compounding the difficulties already enumerated.
SUMMARY OF THE INVENTION
The present invention proposes a resolution to these problems and offers an attractive, effective solution to the difficulties described above. It does not harm the environment, and eliminates the risk of triggering an uncontrolled avalanche in exposed locations where other known methods are unsuitable or ineffective.
This goal is achieved by the device wherein the exploder consists of one main cylinder which is essentially perpendicular to a support base placed flat on the ground, a positioning tube connected to the main cylinder and mounted on a rigid seat attached to the side of the mountain, a supply conduit furnishing explosive gas mixture to the positioning tube and the main cylinder, and ignition means located upstream of the supply conduit for igniting the explosive gas mixture.
According to one preferred embodiment, said positioning tube is articulated to said rigid base on a generally horizontal axle.
According to a particularly advantageous embodiment, the supply conduit is designed to convey the explosive gas mixture and at least one spark plug is attached to said conduit to ensure that the explosive gas is ignited.
The supply conduit is preferably connected to two flexible conduits which are respectively connected to reservoirs of oxygen and combustible gas.
According to a preferred embodiment, the spark plug is connected to an ignition system consisting of a pressostat associated with a dual-state microswitch, a condenser, an electric battery, and an igniter, said microswitch providing communication between the condenser and the igniter when in the first state, and between the condenser and the battery when in the second state.
The device advantageously comprises several exploders and the supply conduit comprises several interconnected portions, arranged so that the distance between the connection zone and the exploders is the same for all the exploders so that simultaneous explosions can be provoked.
It is preferable for the main cylinder seating to be made of concrete equipped with a rubber plate to cushion the fall of the cylinder.
The main cylinder advantageously has a hollow cylindrical body and an air evacuation outlet. The cylindrical body is preferably surmounted by a mass at the upper extremity.
REFERENCES:
patent: 2459854 (1949-06-01), Swift
patent: 4353301 (1982-10-01), Jacobsen
patent: 5107765 (1992-04-01), Schippers
patent: 5872326 (1999-02-01), Manhart
patent: 798536 (1997-01-01), None
Chambers Troy
Davis & Bujold P.L.L.C.
Jordan Charles T.
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