Abstract: A drilling tool (10) of the displacing type comprises a displacing head (22) including a cylindrical mid head portion (24) and lower and upper frustoconical head portions (26, 28). A lower drill portion (12) carries a helical rib (16) which also extends over the lower head portion (26), all portions of this rib being of equal height. The upper head portion (28) is formed with spiroconical displacing walls (32).

Abstract: A drilling machine for a mobile drilling appliance which includes a housing which is adapted to travel along a jobber, a drive motor mounted on said housing, a pinion operatively connected to said drive motor, a step-down gear rotatably engaging said pinion, a driving socket located in the vicinity of a side face of said housing that contains a central opening which is adapted to receive a driving shaft that in turn is adapted to be connected to a drilling tool, and a driving ring positioned in said driving socket and engageable with said step-down gear.

Abstract: Improvements to diesel power hammers which allow the hammers to be operated smokelessly are disclosed. Kerosene and synthetic oil replace diesel fuel and mineral oil as fuel and lubricant, respectively, in hammers incorporating prior art design improvements by Makers thereof. Other combustibles such as gasoline may be added to the kerosene fuel to improve the quality of combustion and thereby further reduce the emission of smoke.

Abstract: In a hydraulic drive, in which a double-acting working cylinder (10) is connected to the hydraulic power source by very long working lines (20, 22), it is proposed to connect a bypass line (36) containing a normally closed bypass valve (38) to the ends of the working lines (20, 22) nearest the cylinder. The bypass valve (38) is periodically opened to allow the fluid contained in the working lines (20, 22) to be completely replaced.

Abstract: An apparatus for screwing a concrete pile (10) into ground comprises a rotary drive (26, 40, 42) and a linear drive (46, 48) both acting on the pile. An angle indicator (58) is associated to the rotary drive (26, 40, 42) and a linear position indicator cooperates with the linear drive (46, 48). A control unit (60) receives the output signals of the angle indicator (58) and the linear position indicator (56) and provides control signals to the rotary drive (26, 40, 42) and the linear drive (42, 48) corresponding to the pitch of the helical rib (16) formed on the concrete pile (10).

Abstract: A diesel type pile-driver has a cup-shaped monkey (36) accommodated in a sliding fit on the external face of the lower end of the cylinder.

Abstract: The invention relates to a flexible two-dimensional material, as well as to a method and an apparatus for the production thereof.