percussive well borer

A percussive hole borer has striker, tip and cylindrical body working with a split sleeve forming support wedges working with the body and a set of wedge shaped bearings via sleeve segments. The bearings (20) and segments (21) of the sleeve (19) should rotate in radial planes in the tip (18) which is axially bored (27) and whose bottom endface lies above that of the body (15). Sleeve and tip have toroidal surfaces to secure the bearings and segments and the inclined (17) body part is grooved lengthways for the bearings. The incline angle ratio to that of the body grooves equals the cosine of the angle between the surfaces of symmetry of the segment and cooperating bearing. - Boring is by pneumatic striker (3) with a reversing port (11) and two stage sleeves (5) in conventional cycles, the sleeve expanded with each upward return stroke via segments and bearings tight onto the hole wall at maximum diameter, the bearings sprung (25) onto the inclined body, thus holding the sleeve at this diameter throughout, until target depth is reached. Then the bearings slide along the body slope grooves, turn and entrain the sleeve segments to contract the sleeve for retrieval etc. A percussive hole borer has striker, tip and cylindrical body working with a split sleeve forming support wedges working with the body and a set of wedge shaped bearings via sleeve segments. The bearings (20) and segments (21) of the sleeve (19) should rotate in radial planes in the tip (18) which is axially bored (27) and whose bottom endface lies above that of the body (15). Sleeve and tip have toroidal surfaces to secure the bearings and segments and the inclined (17) body part is grooved lengthways for the bearings. The incline angle ratio to that of the body grooves equals the cosine of the angle between the surfaces of symmetry of the segment and cooperating bearing. - Boring is by pneumatic striker (3) with a reversing port (11) and two stage sleeves (5) in conventional cycles, the sleeve expanded with each upward return stroke via segments and bearings tight onto the hole wall at maximum diameter, the bearings sprung (25) onto the inclined body, thus holding the sleeve at this diameter throughout, until target depth is reached. Then the bearings slide along the body slope grooves, turn and entrain the sleeve segments to contract the sleeve for retrieval etc. (Machine-translation by Google Translate, not legally binding) UN DISPOSITIVO PARA PERFORAR POZOS EN EL TERRENO COMPRENDE UN MECAN