Abstract: The present disclosure provides a drilling method and drill. According to a disclosed method, multiple reciprocating rock-breaking elements, including a hammer drill bit, are used. The elements are moved in alternation to each other such that the net volume displacement by the moving parts is reduced for reducing compression work and thus for losing useful energy from the available amount from the drill bit engine for rock breaking. If desired, a small component of the net volume displacement is kept for enhancing PVW for enhancing rock chipping by tensile strength. The method also includes synchronizing the peak of the pressure depression wave with that of the impact moment of the drill bit's reciprocating motion to enhance, rather than hamper, rock breaking by the creation of PVW.

Abstract: The present disclosure provides a drilling method and drill. According to a disclosed method, multiple reciprocating rock-breaking elements, including a hammer drill bit, are used. The elements are moved in alternation to each other such that the net volume displacement by the moving parts is reduced for reducing compression work and thus for losing useful energy from the available amount from the drill bit engine for rock breaking. If desired, a small component of the net volume displacement is kept for enhancing PVW for enhancing rock chipping by tensile strength. The method also includes synchronizing the peak of the pressure depression wave with that of the impact moment of the drill bit's reciprocating motion to enhance, rather than hamper, rock breaking by the creation of PVW.

Abstract: Disclosed is a brake system wherein the wheel brake is hydraulically connected with a relief chamber of periodically variable volume. A valve 11 controlled by control electronics is switched to connect the chamber to either the wheel brake or a reservoir synchronously to the direction of movement of a piston in the relief chamber to either increase or decrease pressure at the brake for the purpose of antilock and slip control of the brake.

Abstract: A continuously variable transmission (2) is constructed utilizing a constant displacement pump (4) of fixed fluid power stroke, rather than a variable displacement pump with a variable pump stroke. A fluid motor (14) is driven by the pump and has an output stroke. Means (22) are provided for varying the output stroke without varying the input power stroke.

Abstract: Hydraulic pulse generating apparatus for actuating one or more slave motors, comprises at least one hydraulic master cylinder, which in use is connected to a slave motor by flexible tubing or otherwise.The master cylinder is fitted with a reciprocating plunger which is operated by power actuated driving means, and the cylinder communicates with a hydraulic fluid reservoir which is maintained at a pressure intermediate the maximum and minimum pressures produced in the cylinder by operation of the plunger.Manual control means are provided, to prevent the transmission of pressure pulses to the motor while the power actuated driving means continues to operate and for this purpose the master cylinder preferably communicates with a transfer chamber, the volumetric capacity of which is variable by operation of the manual control means.Means are also provided whereby, when the capacity of the transfer chamber is thus increased beyond its normal capacity, the further inflow of fluid from the reservoir is prevented.

Abstract: In apparatus for controlling a lubricating device which is actuated by pulses of compressed air, the apparatus including a drive piston disposed in a cylinder to undergo reciprocating movement under the action of each such pulse and a control valve disposed between the source of such pulses and the lubricating device, the control valve is periodically opened to permit one such compressed air pulse to be delivered to the lubricating device only after a predetermined number of compressed air pulses have been produced, by means of a stepping mechanism which includes a reciprocating pump connected to be driven by the drive piston to supply, in response to each cycle of movement of the drive piston, a predetermined quantity of liquid, an actuating cylinder containing an actuating piston and arranged to receive each such quantity of liquid to move the piston in a unidirectional, step-wise manner so that the actuating piston advances through the cylinder in discrete steps as a series of quantities of liquid are supp