Abstract: A vibratory apparatus comprises a shaft mounted for rotation about an axis and having weight structure mounted thereon to effect vibration in response to shaft rotation. The shaft may be initially balanced or unbalanced. According to one series of embodiments, a preloaded spring means maintains a primary weight structure in the relatively reduced eccentric position until a first predetermined magnitude of rotational shaft velocity is achieved. The primary weight structure thereafter moves outwardly against the force of the spring means with the spring means also moving to an eccentric position. At a higher, second predetermined magnitude the eccentricity of the primary weight structure and spring means is maximum. Until a higher, third predetermined magnitude of rotational shaft velocity, a secondary movable weight structure is retained in the relatively reduced eccentricity position by a preloaded spring means.

Abstract: A vibratory apparatus comprises a shaft mounted for rotation about an axis and having weight structure mounted thereon to effect vibration in response to shaft rotation. The shaft may be initially balanced or unbalanced. According to a first series of embodiments, secondary movable weight structure is mounted on the shaft for outward movement against spring action when the rotational shaft velocity reaches a predetermined magnitude to reduce vibration caused by the primary weight structure. In another embodiment, combined weight/spring structure is utilized for the same purpose. Various other types of springs may be used. In this manner the vibrational amplitude of the apparatus is caused to vary as a function of the rotational velocity of the shaft.

Abstract: A rotatable vibration generating mechanism includes a movable eccentric weight. Said weight is variably positioned to change the eccentricity of the mechanism by the controlled flow of fluid (liquid or air) when the mechanism is stationary or rotating. More than one weight may be used and a combination of movable parts may be used as a compound movable weight. The fluid pressure resisting the movement of the weight is recorded and thus the centrifugal force generated is known through calculation, since the weight, shape, geometric configuration, and positioning of the eccentric weight is known. The centrifugal force can be changed without changing the rotating speed through the use of valve means regulating fluid flow to change the position of the eccentric weight. Pressure sensitive controls may be adapted to the valve means to make the flow control automatic so that the centrifugal force can be held constant or limited through a specified vibrational speed range.