Vibrator device driven by at least one imbalance generator

Claim 1

In a vibrator device of the type driven by at least one imbalance generator and secured to an apparatus to be vibrated, the effective mass of the latter being connected to a free mass by opposingly working preloaded springs disposed between two spring supports, said free mass includes said imbalance generator, the preload of said springs being variable by changing the distance between said supports, the improvement comprising, A. a housing disconnectably affixed to said effective mass and including a base having opposed faces, B. first and second vibrator plates disposed parallel to one another adjacent to, and spaced from the opposed faces of said base and constituting said supports and forming part of said free mass, said at least one imbalance generator being affixed to said first vibrator plate, C. at least one bolt passing through said base and connecting said vibrator plates with one another and adjustably determining the distance therebetween and permitting displacement thereof towards said base, said bolt forming part of said free mass, and D. at least one spring pair consisting of a first and second individual spring, said first individual spring being fitted in a preloaded condition between one face of said base and said first vibrator plate, urging the latter away from said base, said first vibrator plate, urging the latter away from said base, said second individual spring being fitted in a preloaded condition between the outer face of said base and said second vibrator plate, urging the latter away from said base, the center of gravity of said vibrator device being disposed approximately in a medial plane extending between said first and said second individual spring.