Abstract: This invention relates to a method and device for driving tools into the ground, comprising a chassis in which is slidably mounted an anvil connected by a set of rods to said tool and a hammer sliding in said chassis to strike the anvil, which device further comprises an electro-magnet mounted to slide in said chassis and above said hammer, which is connected to an electrical source as well as to lifting means for gripping the hammer by magnetic attraction after it has dropped on the anvil and to lift the hammer to the upper part of the chassis in order automatically to allow it to drop again by gravity onto said anvil, and in which the hammer comprises in its part opposite the one which comes into contact with the anvil a permanent magnet to increase the force of attraction of the hammer against the electro-magnet, or to create a force of repulsion by change of polarity of the electro-magnet in order to promote separation of the electro-magnet and the hammer and to communicate an initial velocity to said ham

Abstract: The present invention relates to a device for detecting micro-leaks of gas by directing the infrared radiation created by a thermal gradient onto a wall, which device comprises an enclosure provided with an opening equipped with sealing means designed to be placed in contact with the wall, a sealed tank separated from said enclosure by a partition wall, said tank housing an infrared camera of which the objective is situated in front of a lens which is permeable to infrared radiations, means for sealingly applying the enclosure against the wall, means for creating a partial vacuum inside the enclosure, and an insulating screen placed in the center of the opening of the enclosure and applied against said wall in order to filtrate the gas leaks drawn in by the vacuum effect, to obtain a thermal gradient detectable by thermovision.