Abstract: The invention concerns a device (10) for provoking an avalanche comprising a gas gun (12) the end of which is fixed to a seat (13) solidly anchored to the mountain and the downstream end of which is born by at least one leg (14) such that the mouth of the gun is arranged above the snow cover. The gun (1q2) upstream end is fixed to the seat (13) by an articulation (17), and the downstream end is ballasted, the leg (14) being mounted freely on a base (15) made integral with the ground. The leg (14) is hollow and contains ballast consisting of chippings or concrete. The gun (12) is further provided with ignition mechanisms (54) arranged upstream in its proximity and ensures the ignition of the detonating gas mixture.

Abstract: The invention concerns a device for provoking the collapse of a snow cornice comprising several exploders (11). Each exploder (11) consists of a main cylinder (12), perpendicular to the support base (14) arranged flat on the ground, and a positioning tube (13) connected to the main cylinder and mounted on a rigid seat (15) fixed to the mountain side. A supply conduit (20), connected by conduits (23, 24) respectively to an oxygen cylinder and a propane cylinder stored in a shelter (22), supplies via conduit sections (9) a detonating gas mixture, obtained from two gases, into the positioning tube (13) and into the main cylinder (12). Igniting means (21) mounted upstream of the supply conduit (20) ensure the ignition of the detonating gas mixture.

Abstract: The above device consists mainly of a rigid explosion tank (10) with a closed rear end (11) and a front opening (12). Said tank is mounted in the direction of the slope on which the avalanche is to be triggered. It is connected to a fuel gas supply station (19) and to an oxygen-carrying gas supply station (20). These two stations are linked by pipes (17 and 18) to injection nozzles (16) situated inside the tank (10). An ignition device (29) is mounted in the bottom of the tank and can be operated by remote control by means of a triggering device (30). An advantage of the above device is that the explosion is exponentially propagated inside the rigid explosion tank and causes a powerful high-velocity blast to be expelled from the latter.

Abstract: A process and an apparatus for automatically positioning an explosive charge at a predetermined position above the surface of the snow for setting off an avalanche.The apparatus includes an electric winch for unwinding and rewinding a suspension string attached to the explosive charge. The winch is swingably mounted in a container of the apparatus in a manner so as to oscillate between up and down positions depending upon whether the string is tensioned or not. Magnetic detectors associated with the winch count and signal the number of turns of its drum to a programmable electronic unit. Coded wheels are provided to select a maximum height of descent and a lifting height for the charge after contact with the snow.

Abstract: The pulley support head according to the invention is adapted to permit easy adjustment of the orientation of the pulley at any time, even when the pulley is turning.The support head comprises a rigid frame (11) having a front extremity (13) which carries the pulley outside the frame, and mechanical means for pivoting this axle with respect to the frame on two substantially orthogonal axes (23, 40) defined by bearing edges provided on the frame. A first bearing edge (22) is situated in the front part of the frame. A threaded rod (27) articulated on the rear extremity (14) of the axle and connected to the frame by means of screws (31) permits pivoting the axle on the first edge (22). A guiding fork (34) defines a second pivoting axis (40) near to the rear extremity of the axle.Such a support head may be utilized in any cable conveyor, for example a ski tow or a building site cableway.