Abstract: In a mass compensated impacting apparatus composed of at least one pair of impacting tools and a common tool carrier supporting the tools, there is provided a two-mass vibration excitation system associated with each tool and including vibrating masses which are positively linearly guided in an essentially non-resilient manner, and a unit driving the vibratory masses with phase relationships such that the resulting average of all mass forces becomes at least approximately zero.

Abstract: Centering and cooling equipment for a hydraulic vibration generator, with a pulsation generator pressurizing a cylinder containing a movable piston, composed of a feed system and a flushing system. The feed system includes spring-loaded non-return valves connecting a fluid reservoir to feed pipes connecting the pulsation generator to the cylinder chambers, and operates to supply cool pressure fluid from the reservoir when pressure in the cylinder chambers falls below a predetermined level. The flushing system includes a control bush/control plunger unit, bush and plunger of which are respectively connected to the piston and cylinder or vice versa, the plunger cooperating with channels in the bush to connect either feed pipe to a return passage according to the off-center position of the plunger in the bush. This system operates to withdraw a quantity of pressure fluid, dependent on pressure and stroke, from the cylinder chambers with each piston stroke.

Abstract: A vibration generator has a driven excitation shaft on which are fixed two axially-spaced first eccentric weights. A second eccentric weight positioned between the two first eccentric weights also rotates with the excitation shaft but is angularly adjustable thereon about the longitudinal axis of the shaft in order to adjust the vibration amplitude. Such adjustment employs a pawl mounted on one of said first eccentric weights for two-and-fro movement tangentially of a gear ring mounted on said second eccentric weight and with the toothed periphery of which the pawl engages. The second eccentric weight is lockable in adjusted position by a friction disc mounted on said one first eccentric weight and into frictional engagement with which the second eccentric weight is urged by a set of annular disc springs disposed in compression between the second eccentric weight and the other of said first eccentric weights.

Abstract: A hydraulically operated vibration exciter for a vibrating compactor of the kind comprising a piston in a cylinder, the piston and cylinder being arranged to move to and fro relative to each other, a source of liquid under pressure, a pressure line connecting the source to the cylinder and means for causing the liquid to move to and fro between the source and the cylinder to bring about the relative movement between the piston and cylinder is cooled by a method in which, during the relative movement, a quantity of the liquid is withdrawn from the cylinder and this quantity is not returned to the cylinder in the subsequent stroke, but is replaced by a fresh quantity of liquid at a lower temperature.

Abstract: In an eccentric drive system including a rotatably mounted driven shaft, at least one primary eccentric mass fixed to the driven shaft for rotation therewith, an additional eccentric mass mounted for rotation with the shaft in a manner to permit periodic adjustment of the angular position of the additional mass relative to that of the primary mass, the shaft is provided with a shaft portion presenting an outer periphery which is arranged eccentrically to the axis of rotation of the shaft, the additional mass is mounted on the shaft portion to be angularly movable relative to that portion, and the system is further provided with a spring element connected between the additional mass and the shaft for producing a force about the axis of the shaft urging the additional mass into an initial angular position relative to the shaft, and with a fastening unit disposed between the shaft and the additional mass and actuatable between a released position in which it permits the additional mass to undergo angular displac

Abstract: A compact and stable vibratory tamper of relatively low height comprises a crank case, a laterally mounted motor which is arranged to impart a linear reciprocating motion to an intermediate member via a planetary gear arrangement, a crankshaft, and a crank arm, and a tamping foot which is moved by the intermediate member by means of at least two oppositely acting springs which act between the intermediate member and the tamping foot and which overlap at least partially in the axial direction.