Abstract: An improved unbalance vibration generator adapted to be driven at varying rotational speeds while maintaining a substantially constant exciting force throughout a range of rotational speeds. The generator includes an unbalance mass comprising first and second unbalance masses journaled for rotation and angularly offset from each other 180.degree. about the axis of rotation. The first unbalance mass is journaled on the axis of rotation and the second unbalance mass is radially movable in relation thereto. This radial movement is restrained by cam and spring means which provide predetermined non-linear restraint of the second unbalance mass relative to the first unbalance mass.

Abstract: The screening motion of a screening machine is changed by adding ballast, while the machine is in operation, to selected closed compartments moving with the vibrating assembly. In the preferred embodiment, the ballast is added through flexible tubing which is inserted through ports that close with spring loaded oil hole caps. When the tubing is pulled from the ports, the caps snap closed to capture the ballast in the selected compartments.

Abstract: This invention provides novel mechanical work generating means. Basically, the novel mechanical work generating means provided by the present invention comprise: first means for mechanically generating a heat component of work; second means, mechanically interconnected to the first means, for mechanically generating a non-heat component of work; and third means, mechanically interconnected to the first and second means, for combining the heat and non-heat components of work into a resultant mechanical work output.

Abstract: An improved rotary vibrator unit of the type comprising a first member adapted to be mounted on a shaft for rotation thereon or therewith, a mass mounted on said first member and adapted to be moved under the influence of centrifugal force during rotation of both said members and said mass in a radial direction relative to the axis of rotation thereof to unbalance the unit and cause it to vibrate, said unit further including resilient means adapted to provide a first resistance to radial movement of said mass through a first range of angular motion of said unit and including means providing a second resistance in addition to said first resistance during a second range of angular motion whereby the resistance to radial movement of said mass has a non-linear characteristic over the full range of angular motion of said unit.

Abstract: An apparatus for facilitating penetration of a ground engaging member, such as a plowshare or fence post, into the ground is disclosed which employs a vibrator having a rotatable mass eccentrically mounted to provide a cyclical motion to the member being caused to penetrate the ground. The apparatus is adapted to independently vary the amplitude and frequency of the cyclical motion imparted to the ground engaging member to adjust for varying soil conditions. One embodiment employs a pair of interconnected balanced vibrators which produce a resultant force acting generally along the longitudinal axis of the ground engaging member.