An ultrasonic displacement measurement system for hydraulic accumulators (3) has a movable separating element (5) separating two media chambers (9, 11) from each other in a media-tight manner within a housing (7). One media chamber (9) holds a compressible fluid or an incompressible fluid. The other media chamber (11) holds a compressible working gas. The particular position of the movable separating element (5) within the housing (7) can be detected by an ultrasonic sensor (13) that performs the position detection of the separating element (5) on the side of the media chamber (11) having the compressible fluid. A method for ultrasonic displacement measurement uses that system.

A method of assembling a solenoid valve assembly is disclosed. The method includes inserting an axial end of a valve housing partially through an aperture of a tab. The axial end of the valve housing extends partially through an opening of a solenoid housing. An interlocking element is positioned in a first axial end of the solenoid housing. The method includes inserting a petal of the valve housing into a pocket of the interlocking element. The method includes engaging the interlocking element with an installation tool and rotating the installation tool to rotate the interlocking element and the valve housing until a lip of the solenoid housing is axially positioned between (1) the petal of the valve housing and (2) a protrusion of the tab, such that the valve housing, the tab, and the solenoid housing are fixed to each other.

A position-determining actuator includes a rod, a barrel, a wave detector, and a controller. The barrel at least partially surrounds a piston of the rod so as to define a cap-side void and allow the rod to telescope relative to the barrel. The wave detector is associated with the cap-side void and configured to read fluid pressure of a hydraulic fluid disposed in the cap-side void. The controller is configured to receive, from the wave detector, a pressure reading from within the cap-side void; analyze the pressure reading to determine an extension standing wave; and analyze the extension standing wave to determine an extension dimension of the cap-side void.

A method of assembling a solenoid valve assembly is disclosed. The method includes inserting an axial end of a valve housing partially through an aperture of a tab. The axial end of the valve housing extends partially through an opening of a solenoid housing. An interlocking element is positioned in a first axial end of the solenoid housing. The method includes inserting a petal of the valve housing into a pocket of the interlocking element. The method includes engaging the interlocking element with an installation tool and rotating the installation tool to rotate the interlocking element and the valve housing until a lip of the solenoid housing is axially positioned between (1) the petal of the valve housing and (2) a protrusion of the tab, such that the valve housing, the tab, and the solenoid housing are fixed to each other.

The subject matter of this specification can be embodied in, among other things, a position sensor system that includes a sensor housing defining a first cavity having a first face, a fluid effector including an actuator housing having an inner surface defining a second cavity, and a moveable body having a second face and configured for reciprocal movement within the second cavity, an acoustic transmitter system configured to emit a first emitted acoustic waveform toward the first face, and emit a second emitted acoustic waveform toward the second face, and an acoustic receiver system configured to detect a first reflected acoustic waveform based on a first reflection of the first emitted acoustic waveform based on the first face, and detect a second reflected acoustic waveform based on a second reflection of the second emitted acoustic waveform based on the second face.

A hydraulic drive unit for a shaping machine comprising a pump driven by a motor, a closed-loop or open-loop control unit for closed-loop and/or open-loop control of the drive unit to a reference operating point of the drive unit, and a memory connected to the closed-loop or open-loop control unit, wherein a relationship between a parameter characteristic of a sound directly or indirectly caused by the drive unit and a data set representing various operating points of the drive unit is stored in the memory and the closed-loop or open-loop control unit is adapted to select the reference operating point on the basis of the relationship.

A position detection system comprising a hydraulic actuator including a cylinder and piston adapted to move within the cylinder; an ultrasonic transducer adapted to detect an ultrasonic signal indicative of a position of the piston within the cylinder; and a controller. The controller is adapted to receive the ultrasonic signal from the ultrasonic transducer, implement a cross-correlation function to identify a first echo and a second echo in the ultrasonic signal, determine a velocity of first echo and the second echo, and determine the position of the piston within the cylinder in response to determining that the difference between the velocity of the first echo and the second echo and a theoretical velocity is less than a threshold.

A system is provided for determining piston position and for monitoring and maintaining stroke rate in a hydraulic lift system comprising a lift cylinder, a reversible hydraulic pump, a motor and a flywheel. A method is further provided for managing energy requirements of a hydraulic lift system comprising a lift cylinder, a reversible hydraulic pump, a motor and a flywheel.