Abstract: A hydraulic control system includes a first motor, a second motor, a pump operatively associated with the first motor, a first coupling valve operatively associated with the second motor, first parallel valves operatively associated with the second motor, and a first switching valve operatively associated with the first coupling valve and the first parallel valves. The first switching valve is configured to switch the first coupling valve between a first coupling state and a second coupling state opposite the first coupling state and to switch the first parallel valves between a first parallel state and a second parallel state opposite the first parallel state. While the first parallel valves are in the first parallel state a portion of the output of the first motor drives the second motor while the first parallel valves are in the second parallel state, the output of the pump drives the second motor.

Abstract: A hydraulic control system includes a first motor, a second motor, a pump operatively associated with the first motor, a first coupling valve operatively associated with the second motor, first parallel valves operatively associated with the second motor, and a first switching valve operatively associated with the first coupling valve and the first parallel valves. The first switching valve is configured to switch the first coupling valve between a first coupling state and a second coupling state opposite the first coupling state and to switch the first parallel valves between a first parallel state and a second parallel state opposite the first parallel state. While the first parallel valves are in the first parallel state a portion of the output of the first motor drives the second motor while the first parallel valves are in the second parallel state, the output of the pump drives the second motor.

Abstract: A hydraulic control system includes a first motor, a second motor, a pump operatively associated with the first motor, a first coupling valve operatively associated with the second motor, first parallel valves operatively associated with the second motor, and a first switching valve operatively associated with the first coupling valve and the first parallel valves. The first switching valve is configured to switch the first coupling valve between a first coupling state and a second coupling state opposite the first coupling state and to switch the first parallel valves between a first parallel state and a second parallel state opposite the first parallel state. While the first parallel valves are in the first parallel state a portion of the output of the first motor drives the second motor while the first parallel valves are in the second parallel state, the output of the pump drives the second motor.

Abstract: A piercing apparatus compact in size having a decreased number of hoses is suited for use as an iron runner port-opening machine for a blast furnace or the like furnace in an iron mill.

Abstract: A piercing apparatus compact in size having a decreased number of hoses is suited for use as an iron runner port-opening machine for a blast furnace or the like furnace in an iron mill.

Abstract: The invention pertains to a hydraulic rotary drive for the rotating rod assembly of a drilling machine which contains at least two hydraulic motors (1-3) with the motor shafts (34-36) that are connected to a common output shaft (11) by means of a gear, with a clutch (4-6) being arranged between the motor shaft (34-36) of each hydraulic motor (1-3) and the gear such that the rotational movement of each hydraulic motor (1-3) can be disengaged from the rotational movement of the output shaft (11). The invention aims to develop a highly variable rotary drive for ground and rock drilling machines.

Abstract: A pressure amplifier can be mounted above a drill bit at the lower end of a drill pipe for generating an increased fluid pressure in a drilling fluid flow to, for example, obtain an increased drilling effect, A reciprocating piston in a cylinder has at one side (a low pressure side) a large piston area and also has a first opposite piston area and a second opposite and relatively small piston area, which generates an increased pressure. A valve device controls drilling fluid flows to and from the piston. Beyond one end of the cylinder there is provided a hydraulic rotary motor adapted to be driven by the pressure difference between the drilling fluid flows in the drill pipe and an annulus. A transmission mechanism converts the rotation of the hydraulic motor into intermittent movements of the valve device between two operative positions.

Abstract: An arrangement for tightening screw connections comprises a screw spindle turnable by a screw tool, at least two-stage rotary drive for the screw spindle, the drive providing a coarse driving for pre-tightening of a screw connection and a fine driving for obtaining the desired screwing condition, a measuring value pick up for obtaining measuring values which correspond to a value of an available screwing condition, a control device for providing switching signals for the rotary drive in dependence on the measuring values determined by the measuring value pick up, the screw spindle being subdivided into at least three spindle parts, including a first spindle part connected with the drive motor for providing the coarse driving, a second spindle part, and a third spindle part, and an auxiliary drive providing the fine driving and having a drive element which together with the auxiliary drive form an independently operating structural unit which forms the second spindle part and is integrated between the first sp

Abstract: A drill rig includes a main engine which drives a drilling spindle through a clutched transmission. A protective cage surrounds the spindle when the transmission is in gear to prevent workmen from being injured by drilling tools. An auxiliary drive motor operates the spindle for a limited number of revolutions when the transmission is in neutral and the protective cage is open to permit workmen to rotate the spindle to add and remove augers, couple and uncouple drilling rods, and perform other necessary tasks.

Abstract: This invention relates to a drive unit comprising a frame; a rotating shaft, a first fluid motor presenting a cam fixed with respect to the frame; and a cylinder block fast with the shaft driven by the first motor at a first speed of rotation.According to the invention, the shaft presents a recess conveying a drilling fluid; the cylinder block of the first motor is coaxial to the axis of rotation; drive unit comprises a second motor coupled in rotation to the shaft and driving it at a second speed of rotation higher than the first speed of rotation; a first pinion gear is fast with and coaxial to the shaft; the second motor presents an output shaft fast with a second pinion gear meshing with the first pinion gear; and the first motor is of the type with "disengageable pistons".One application is the production of a high-performance drilling assembly.