Abstract: A device for exciting seismic vibrations includes a hydraulic cylinder comprising first and second caps; a partition configured to divide the cylinder into first and second chambers; a rod and piston assembly configured to move in the first chamber; an actuator connected to a rod of the assembly; a first plate connected to the assembly and configured to move in the second chamber; a waveguide configured to move in the second chamber; and a second plate connected to the waveguide. The assembly comprises an axial through channel in a body of the assembly. The actuator is configured to move the rod of the assembly in the through channel between first and second positions. In the first position, a first flow is prevented between first and second sides of the first plate. In the second position, the first flow is allowed between the first and second sides of the first plate.

Abstract: A device for exciting seismic vibrations includes a hydraulic cylinder comprising first and second caps; a partition configured to divide the cylinder into first and second chambers; a rod and piston assembly configured to move in the first chamber; an actuator connected to a rod of the assembly; a first plate connected to the assembly and configured to move in the second chamber; a waveguide configured to move in the second chamber; and a second plate connected to the waveguide. The assembly comprises an axial through channel in a body of the assembly. The actuator is configured to move the rod of the assembly in the through channel between first and second positions. In the first position, a first flow is prevented between first and second sides of the first plate. In the second position, the first flow is allowed between the first and second sides of the first plate.