Abstract: A vibratory road roller has a drum adapted to be vibrated as it rolls along the ground, to this end the drum containing a vibrator device of the type which produces a vibratory effect as a result of rotation of an out-of-balance mass. The vibrator device comprises a casing, fixed to an end plate of the drum, and a rotor which has a fluid-containing cavity with the contained body of fluid contacting a swept internal annular surface of the casing. A piston movable radially in the rotor and/or the body of fluid provides the out-of-balance mass, and the vibratory force is transmitted to the casing and hence to the drum by the fluid pressure acting on the swept annular surface of the casing. The rotor structure itself is mechanically balanced so that substantially no vibratory force is transmitted through the rotor shaft and bearings.

Abstract: A hydraulically-operated road breaker comprises a casing with a tool mounting and housing an oscillatory piston/striker and cylinder arrangement. A sequence valve mounted in the casing controls pressurization and exhausting of the piston to produce power and return strokes of the piston. Pilot port means positioned in the cylinder of the device are uncovered, at the end of each return stroke of the piston, to allow a valve-actuating flow of hydraulic fluid through the port means to change over the sequence valve and thereby cause stroke reversal of the piston. Manually-operable stroke selection means provide for adjustment of the position of the piston in the cylinder at which the valve-actuating flow occurs, whereby to vary the piston stroke.

Abstract: Vibrator devices, of the type which produce a vibratory effect as a result of rotation of an out-of-balance mass, comprise a casing and a rotor which has a fluid-containing cavity with the contained body of fluid contacting a swept annular surface of the casing. A piston movable radially in the rotor and/or the body of fluid provides the out-of-balance mass and the vibratory force is transmitted to the casing directly by the fluid pressure on the swept annular surface thereof. The rotor structure is mechanically balanced so that substantially no vibratory force is transmitted through the rotor shaft and bearings.