SUBSURFACE PNEUMATIC HAMMER

The proposed invention pertains to mining and quarrying, in particular to tools used for extracting useful minerals, specifically high-pressure subsurface pneumatic hammers. The proposed subsurface pneumatic hammer comprises a housing (1); a graduated hollow piston-hammer mounted in the housing so as to be capable of reciprocal motion, the large-diameter stage (2) of the piston-hammer being mounted in the housing with a gap, a labyrinth seal (3) being provided on the external surface; a compound transition piece (4) in which the smaller-diameter stage (5) of the piston-hammer is directly fitted; a transition sleeve (6) and a gas-distributing pipe (7) mounted within it. The outer surface of the small diameter part of the transition element (4) has longitudinal grooves (8), radial apertures (9) and an additional annular bore (10). In the large diameter stage (2) of the piston-hammer are provided gas-distributing radial apertures (11, 12). The piston-hammer is mounted in the housing (1) to form useful-stroke and blank-stroke chambers (13 and 14 respectively). The gas-distributing pipe has radial apertures (15) along the edges of which are provided annular bores (16, 17) which ensure more prompt opening and closure of the chambers (13, 14). The proposed pneumatic hammer provides increased power (without altering the energy of the blow), improved reliability, and lengthened useful life while simplifying manufacture and reducing the associated costs. This is done by taking the power load from the large-diameter piston-hammer and thereby reducing wear. Cette invention se rapporte au domaine de l'industrie minière, notamment à des appareils d'extraction de produits fossilisés recherchés, et plus précisément à un marteau pneumatique immergé et à haute pression. Ce marteau pneumatique immergé comprend un corps (1) dans lequel se trouve un piston-percuteur creux et étagé pouvant effectuer un mouvement de va et vient. L'étage de grand diamètre (2) de ce piston percuteur est situé dans le corps de manière à former un jour, tandis que sa surface externe comporte un joint d'étanchéité de type labyrinthe (3). Ce corps (1) comporte également un raccord complexe (4) dans lequel est monté directement un étage d'un diamètre moindre (5) du piston-percuteur, ainsi qu'un tube de transfert (6) dans lequel se trouve une conduite de distribution des gaz (7). La surface externe de la partie d'un moindre diamètre du raccord (4) comporte des fentes longitudinales (8), des ouvertures r