Abstract: A power generator for use in a wellbore formed in an earth formation, including an internal combustion engine having a cylinder and a piston defining a combustion chamber in the cylinder, the engine being arranged to induce a reciprocating movement to the piston relative to the cylinder upon combustion of a combustible gas mixture in the combustion chamber, and a linear electricity generator having a stator and a drive shaft. The generator is arranged to generate electricity upon a reciprocating movement of the drive shaft relative to the stator, and the piston is connected to the drive shaft so as to transmit the reciprocating movement of the piston to the drive shaft.

Abstract: In a computer including an operating system comprising a virtual storage organization concept providing storage space for parallel program execution in pre-allocated partitions of a virtual address storage containing shared areas and private areas in several address spaces, there are provided dynamic partitions (P1, P2, . . . N1, N2, . . . O1, O2, . . . ) that are allocatable in addition to the pre-allocated partitions (F1-F8, FA, FB, BG), in dependance from the job to be performed and that are de-allocated after job termination to free the storage area for subsequent use. This concept enlarges the virtual storage area, uses the provided space more effectively and allows the parallel execution of more programs.

Abstract: A device in rock or earth drilling apparatus for rotary drilling including an axially stationary chuck (21) and an axially movable chuck (27) which is rotated by a reversible pressure fluid driven rotary motor (32) having a pressure fluid supply conduit for each direction and which is moved forwards and backwards by a reversible pressure fluid driven feed motor (17) having a pressure fluid supply conduit (18, 19) for each direction, the chucks being actuated to withdraw from or insert in a drill hole a drill string (23) composed by a number of threaded string elements and (are also actuated) to make or break the joints between the string elements.

Abstract: A drill press that is hydraulically driven; the drill press including a turbine motor through which oil is pumped, and the motor having a rotor that is connected to the drill press spindle so to rotate the same.