Piston vibrator

In a piston vibrator for connection to a structural member to cause a vibration thereof comprising a cylindrical housing having a chamber with a free floating piston therein which is axially movable in a translational manner by a pressurized medium, the improvement comprising at least one of said piston and said cylinder housing being made of a lightweight material, first coupling means on said piston and second coupling means on said cylindrical housing, and mass amplifying means, said first coupling means being selectively connected to one of said structural member and said mass amplifying means, said second coupling means being selectively connected to the other of said structural member and said mass amplifying means, said piston vibrator being changeable end for end so that when said mass amplifying means is connected to said piston by said first coupling means, said second coupling means effects a coupling of said cylindrical housing to said structural member to thereby effect a selective regulating of the effective mass of said piston and thereby the amplitude and frequency of relative movement between said cylindrical housing and said piston, and when said mass amplifying means is connected to said cylindrical housing by said second coupling means, said first coupling means effects a coupling of said piston to said structural member to thereby effect a selective regulating of the effective mass of said cylindrical housing and thereby the amplitude and frequency of relative movement between said cylindrical housing and said piston, whereby a first range of selection of the amplitude and frequency of vibratory movement is selective for said structural member, said mass amplifying means and said piston connected together and a second range of selection of the amplitude and frequency of vibratory movement is selective for said structural member, said mass amplifying means and said cylindrical housing connected together.