Abstract: A swing drive system for an excavator is provided which utilizes a prime mover mechanically connected to a first hydraulic pump/motor and a second hydraulic pump/motor mechanically connected to a swing mechanism. The system includes a hydraulic circuit connecting a hydraulic fluid reservoir, a hydraulic accumulator, the first hydraulic pump/motor, and the second hydraulic pump/motor. The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers, including the swing drive.

Abstract: A swing drive system for an excavator is provided which utilizes a prime mover mechanically connected to a first hydraulic pump/motor and a second hydraulic pump/motor mechanically connected to a swing mechanism. The system includes a hydraulic circuit connecting a hydraulic fluid reservoir, a hydraulic accumulator, the first hydraulic pump/motor, and the second hydraulic pump/motor. The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers, including the swing drive.

Abstract: A swing drive system (11) for an excavator is provided which utilizes a prime mover (20) mechanically connected to a first hydraulic pump/motor (30) and a second hydraulic pump/motor (32) mechanically connected to a swing mechanism (70). The system includes a hydraulic circuit (31) connecting a hydraulic fluid reservoir (42), a hydraulic accumulator (40), the first hydraulic pump/motor (30), and the second hydraulic pump/motor (32). The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers (62,64,66), including the swing mechanism.

Abstract: A swing drive system (11) for an excavator is provided which utilizes a prime mover (20) mechanically connected to a first hydraulic pump/motor (30) and a second hydraulic pump/motor (32) mechanically connected to a swing mechanism (70). The system includes a hydraulic circuit (31) connecting a hydraulic fluid reservoir (42), a hydraulic accumulator (40), the first hydraulic pump/motor (30), and the second hydraulic pump/motor (32). The system is operable in one mode where the second hydraulic pump/motor acts as a pump to retard movement of the swing mechanism and pressurized hydraulic fluid from the second hydraulic pump/motor is pumped into the hydraulic accumulator. The system is operable in another mode where the pressurized fluid from the hydraulic accumulator is used to assist the prime mover in driving hydraulic consumers (62,64,66), including the swing mechanism.

Abstract: A hydraulic drive comprising multiple gear motors each having a gear motor output shaft, and a common gear engaged by the output shafts of the multiple gear motors. Each hydraulic motor has a characteristic sinusoidal torque ripple out of phase with the characteristic sinusoidal torque ripple of at least one other hydraulic motor for cancelling torque ripple and thereby reducing the torque ripple at the common gear.

Abstract: A variable speed wind turbine utilizes a hydraulic transmission including a hydraulic pump coupled to a rotor and a hydraulic motor coupled to an induction generator to produce variable frequency power that is converted to grid frequency power by electronic controls.

Abstract: A variable speed wind turbine utilizes a hydraulic transmission including a hydraulic pump coupled to a rotor and a hydraulic motor coupled to an induction generator to produce variable frequency power that is converted to grid frequency power by electronic controls.

Abstract: A hydraulic drive comprising multiple gear motors each having a gear motor output shaft, and a common gear engaged by the output shafts of the multiple gear motors. Each hydraulic motor has a characteristic sinusoidal torque ripple out of phase with the characteristic sinusoidal torque ripple of at least one other hydraulic motor for cancelling torque ripple and thereby reducing the torque ripple at the common gear.

Abstract: A two-platen injection molding machine with a stationary mold carrier plate and a movable mold carrier plate which are connected via tiebars having piston-cylinder units which build up and cancel the clamping force. At least one driving cylinder is arranged at the carrier plates for quick driving movement thereof. The tiebars are constructed as loose clamping pins forming the piston rod of the piston-cylinder units. The tiebars are guided through the movable mold carrier plate and the stationary mold carrier plate, and have a hydraulic high-pressure closing unit and a quick-locking mechanism mounted thereon external to the mold carrier plates. Elements are provided which detect the position of the movable mold carrier plate in a defined manner and control the quick-locking mechanism the closing unit, and the driving cylinder.