In a method of operating a tamping unit of a track maintenance machine, the track maintenance machine having the tamping unit is first provided on a track bed. The tamping unit is displaced relative to the track bed. A driving force, acting on the tamping unit and required for the displacement, and acceleration acting on the tamping unit are determined. A ballast force acting between the tamping unit and the track bed is determined by way of the driving force and the acceleration, and is evaluated.

A haptic actuator assembly comprising a fluid reservoir and an actuator is presented. The fluid reservoir may hold a substantially non-compressible fluid, and has a first layer and a second layer that is less rigid than the first layer. The first layer has a first resonance frequency, and the second layer has a lower resonance frequency. The actuator is configured to cause a first vibration in which the first layer vibrates at the first resonance frequency and provides a first amount of displacement or acceleration. The fluid reservoir is configured to transfer a force of the first vibration from the first layer to the second layer to cause a second vibration in which the second layer vibrates at the lower resonance frequency and provides a second, higher amount of displacement or acceleration.

An efficiency-enhanced resonant system is provided with a backing mass connected to a linear vibrator, a parasitic mass connected to the linear vibrator, a positioning spring, a connecting device, and external biasing springs. The linear vibrator provides vibrating force to the parasitic mass which is connected to the connecting device, grasping a working implement. The use of separate positioning spring and external biasing springs accommodates a tuned system that balances the reduction in backing mass movement, avoids backing mass resonance within the working range of frequencies, and maintains a minimized linear vibrator stroke within the optimal range for one-dimensional implements within desired frequency ranges. The linear vibrator provides vibration that manifests as a frequency range of the natural frequency of the combined assembly of the parasitic mass, positioning spring, external biasing springs, connecting device, and implement, so that the resonant system efficiently performs work with minimized wasted energy.

A linear actuator system has a rotary spool valve configuration having a spool, a piston, and a cylinder. The spool and piston have return apertures so positioned, configured and angled to direct return flow towards the center of a spool central return port and spool pressure ports to direct pressurized flow into upper or lower chambers. Rotation of the spool synchronizes and aligns ports and apertures to reverse flows and effect upward and downward translation of the cylinder to vibrationally drive an implement to perform work. The positioned and angled apertures direct the fluid to a region demarcated by a total length of 1.5 times the interior diameter of the spool central return port centered about a piston shoulder. A base plug member having a bull-nose tip, baffles and cavities is disposed within the spool central return port to reduce or eliminate cavitation.

A vibratory compactor is provided. The vibratory compactor may include a compactor plate, a frame coupled to the compactor plate, wherein the frame may include an inner space and a housing. The frame may include a plurality of mounting brackets coupled between a first side member and a second side member of the frame. The vibratory compactor may include a vibration generation device coupled to the compactor plate within the inner space of the frame. The vibratory compactor may include a plurality of isolators, each isolator coupled to one mounting bracket of the plurality of mounting brackets. The housing may be coupled to the plurality of isolators, wherein the housing may include couplers removably coupled to a top surface of the housing. The couplers may be configured for coupling the vibratory compactor to an excavator type vehicle.

A device and a method for generating percussive pulses or vibrations for a construction machine, in which a piston is reversibly reciprocated in a working space in a housing between a first reversal point and a second reversal point, wherein, for the purpose of generating the percussive pulses or vibrations, the piston is set into a reversible movement by a pressure fluid and the pressure fluid is led into and out of the working space in the region of the first reversal point and the second reversal point. The position of the piston is detected by way of a sensor, in that depending on the detected position of the piston a control unit controls at least one controllable valve, through which pressure fluid is led into and/or out of the working space, wherein by the control unit the movement of the piston is controlled.

A mechanism with a base; a pendulum mounted pivotally relative to the base about a pendulum axis; first/second eccentric elements generating first/second moments of gravitational force about first/second axes; and a synchronization system of the first/second eccentric elements according to a synchronized counter-rotating rotational movement. The pendulum axis and eccentric elements' axes are parallel and arranged in the plane integral to the pendulum. The eccentric elements' axes are supported by the pendulum, above and below the pendulum axis. The eccentric elements are movable in synchronized counter-rotating rotation, with cross-centrifugations, the pendulum pivots alternately on one side then the other, amplifying the rotational movement of the eccentric elements, by simultaneous cross-thrusts of the pendulum against the eccentric elements' axes, and by the transmission of torque to the synchronization system, and the energy generated by centrifugation within the mechanism is recoverable by coupling an energy recovery system to the synchronization system.

A roller tube concrete finishing machine includes retractable vibration gangs that can be selectively immersed within wet concrete and then retracted with parallelogram linkage. Spaced-apart, drive parallel rollers are journaled between frame ends for supporting and propelling the machine upon and between parallel form rails. A front roller provide a strike-off function. The vibration gangs are deployed by a retractable, parallelogram linkage that moves them forwardly and downwardly for operation, or which retracts the vibrators inwardly and upwardly relative to the frame. When the vibrators are retracted, the are withdrawn upwardly from the concrete and retracted rearwardly towards the machine front to reduce machine dimensions. Substantial retraction of the vibrators prevents subsequent interference with the rebar below. Vibrator retraction reduces overall machine dimensions for clearance and shipping purposes, with gang vibration arrays nested upwardly and inwardly proximate the front of the machine.

In one embodiment, a centrifugal force generating device comprises a first hydraulic rotor, a second hydraulic rotor, and one or more hydraulic control valves. The first hydraulic rotor comprises a first mass and is configured to rotationally drive the first mass around a first axis of rotation using a first flow of hydraulic fluid through the first hydraulic rotor. The second hydraulic rotor comprises a second mass and is configured to rotationally drive the second mass around a second axis of rotation using a second flow of hydraulic fluid through the second hydraulic rotor. The one or more hydraulic control valves are configured to control the first flow of hydraulic fluid through the first hydraulic rotor and the second flow of hydraulic fluid through the second hydraulic rotor.

Examples of a pressure wave generator configured to generate high energy pressure waves in a medium are disclosed. The pressure wave generator can include a sabot carrying a piston. The sabot can further comprise a locking means to lock the piston in a fixed position when the locking means are activated. When the locking means are in a deactivated position, the piston can be released and can move at least partially away from the sabot. The sabot carrying the piston can be disposed within an inner bore of a housing of the pressure wave generator and can move within the inner bore of the housing from its first end toward its second end along a longitudinal axis of the bore. A transducer can be accommodated in the second end of the housing. The transducer can be coupled to the medium and can convert a portion of the kinetic energy of the piston into a pressure wave in the medium upon impact of the piston with the transducer. The sabot carrying the piston can be accelerated by applying a motive force to the sabot. Once accelerated within the inner bore of the housing the sabot can be decelerated by applying a restraining force to the sabot while the piston can be released at least partially from the sabot to continue to move toward the transducer until it impacts the transducer. Examples of methods of operating the pressure wave generator are disclosed.