Abstract: A method and apparatus for guiding a body into the ground by means of a single hammer acted on by a reaction mass which is driven by a double-acting piston-cylinder unit via a controlled, periodically changing stream of pressure medium and which generates forces which act on the body in its longitudinal direction, the body being driven by first causing the pressure stream to have an approximately sinusoidally pulsating form for imparting a vibratory movement to the hammer, and then, when the speed with which the body is being driven into the ground decreases below a given minimum value, causing the pressure medium to drive the reaction mass according to a periodic, approximately unsteady displacement-time function for imparting a hammering movement to the hammer, while, during such hammering movement, simultaneously monitoring the hammering energy being generated.

Abstract: A submerging ramming arrangement has a housing, an impacting body axially displaceable in the housing for delivering ramming impacts against a ramming pile, a hydraulic drive for displacing the impacting body in the housing, a hydraulic cylinder-and-piston unit arranged in an upper portion of the housing and having a cylinder, a piston sealingly displaceable in the cylinder and subdividing the same into first and second chambers, a piston rod connected with the piston and having a portion extending from the first chamber coaxially outwardly beyond the cylinder, a holding element for mounting the arrangement on a supporting element and provided on the outwardly extending portion of the piston, a hydraulic accumulator communicating with the first chamber of the cylinder-and-piston unit and arranged for receiving excess hydraulic medium under pressure, and an indicating element actuated by the piston of the cylinder-and-piston unit within a predetermined distance from a respective end of the cylinder-and-piston

Abstract: A force-transmitting a drive caps is interposable between a pile driver hammer and a pile to be driven. This cap is formed with an upwardly open cylinder which is of smaller area than the striking face of the hammer. A piston is vertically reciprocal in this cylinder and has an upper surface which is engageable with the striking face of the hammer. The chamber below the piston in the drive cap contains a body of liquid and a body of gas. The gas is pressurized so as to urge the piston into a raised position extending upwardly from the upper face of the drive cap. The piston and hammer are dimensioned so that the hammer first strikes the piston, driving it downwardly in the cylinder, and thereafter strikes the upper surface of the drive cap. The gas body may be held in a separate container within the chamber in te drive cap and the pressure of the gas body is established by the amount of liquid in this chamber.

Abstract: An impact transfer device for pile drivers is made as a one-piece steel unit defining a solid percussion part of a substantially cylindrical configuration with a convex impact surface capable of withstanding steel-on-steel impacts, an intermediate tubular part of substantially frusto-conical configuration integrally connected to the percussion part and a base ring integrally connected to the larger end of the intermediate tubular part having an annular support surface facing away from the impact surface.

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: A fluid operated ram comprises a striker body guided in an upright housing between an active stroke and a return stroke and striking at the end of its active stroke an impact transmitter resting on a member to be driven into the ground by the ram. The striker body is connected by a piston rod to a working piston reciprocatedly arranged in a cylinder coaxially mounted on the upper end of the housing, so that the striker body is driven during reciprocation of the working piston. The working piston is a differential piston and divides the cylinder into a first chamber above the upper larger face of the working piston and a second chamber below the smaller annular face of the differential piston.

Abstract: In apparatus for monitoring the degree of compaction achieved by a compacting device including at least one vibrating compacting tool which device is mounted on a vehicle arranged to travel back and forth over a surface to be compacted, the apparatus including a system for detecting the value of an operating parameter which has a known relationship to the effective power of the vibrating compacting tool during each pass of the vehicle over the surface and which is representative of the degree of compaction achieved, there are further provided a representation storage system connected to the detecting system for separately storing representations of the detected values associated with each direction of travel of the vehicle, and a difference forming unit connected to the storage system for providing a representation of the difference between detected values associated with successive passes of the vehicle in the same direction.

Abstract: A pile driver has a hollow and elongated cylindrical housing. Within the housing, a ram can slide upwardly and downwardly in order to provide the force which can drive a pile into dense strata of the earth. A follower, located partially inside the housing and extending out of the bottom thereof, is struck by the ram and is thus interposed between the ram and the pile to be driven when the device is operated. Various devices are disclosed which serve as shock absorbers, the devices cooperating with the follower and with the housing in order to absorb recoil shock which is reflected back to the pile driver after a blow has been transmitted to the pile by the ram via the follower. These devices are so designed that the exterior diameter of the housing does not have to be substantially increased, which allows the pile driver thus manufactured to drive piles through surrounding guides.

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 pile driver has a hollow and elongated cylindrical housing. Within the housing, a ram can slide upwardly and downwardly in order to provide the force which can drive a pile into dense strata of the earth. A follower, located partially inside the housing and extending out of the bottom therof, is struck by the ram and is thus interposed between the ram and the pile to be driven when the device is operated. Various devices are disclosed which serve as shock absorbers, the devices cooperating with the follower and with the housing in order to absorb recoil shock which is reflected back to the pile driver after a blow has been transmitted to the pile by the ram via the follower. These devices are so designed that the exterior diameter of the housing does not have to be substantially increased, which allows the pile driver thus manufactured to drive piles through surrounding guides.

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: Method and apparatus for controlling a dynamic soil compaction operation, involving striking the soil with vibrating compacting tools, monitoring the vibrational power generated by the tools or the current degree of soil compaction, and controlling the amplitude or frequency of the vibratory movements of the tools as a function of the value of such quantity.

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: The pile-driving arrangement can drive piles both above and below water. It includes a housing containing a gas-filled motion chamber and an impact body movable upward and downward in the motion chamber. A cylinder-and-piston mover includes a cylinder part and a piston part, one part connected with the housing and the other with the impact body, for effecting relative movement between the impact body and the housing. A drive unit on the housing includes a drive motor, a pump driven by the motor and a pressure fluid tank. The drive unit is connected with the housing for limited movement relative to the housing. The cylinder part and the pressure fluid pump are interconnected by flexible conduits leading from the pump to the opposite working chambers of the cylinder part, and a direction-changing device controls fluid flow through the conduits.

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.

Abstract: A hydraulic exciter of vibrations for a vibratory compactor includes an exciter containing a piston which is movable to and fro in the cylinder and either the piston or the cylinder is connected to a compacting member. The movement of the piston in the cylinder is brought about either by an alternating source of hydraulic fluid pressure which forces fluid alternately into and out of the exciter cylinder to move the piston to and fro or by means of a uni-directional source of hydraulic fluid under pressure formed by a hydraulic pressure pump together with a control valve in between the pump and the exciter cylinder. The control valve is operated to switch the supply of hydraulic fluid to and fro in the cylinder from one side of the piston to the other to produce the relative to and fro movement of the piston in the cylinder. The control valve has means for varying its speed of operation to vary the frequency of the vibrations produced by the exciter.

Abstract: A tandem road roller having a pair of rolls arranged one behind the other which are capable of both pivoting relative to each other to negotiate curves and being offset relative to each other to vary the width of the roller track. The roller comprises a first frame member carried on the front roll, a second frame member carried on the rear roll, a connecting bar member hinged at opposite ends to the first and second frame members between the rolls, and an actuating mechanism operating on the first and second frame members to control their angular relationship and to control their lateral offset. Preferably the actuating mechanism includes two fluid pressure operated double-acting piston and cylinder assemblies and in this case one of the piston and cylinder assemblies is preferably arranged parallel to but spaced apart from the intermediate frame member and the other piston and cylinder assembly is connected diagonally between the one piston and cylinder assembly and the intermdiate frame member.

Abstract: A vibratory ground roller composed of a main frame carrying a plurality of rolling drums one in front of the other and a steering frame attached to the back of the main frame has the steering frame connected to the main frame by a plurality of links forming a pivoted link system each link of which is pivotally connected at its front end to the main frame and its back end to the steering frame and the system is so arranged that when the main frame pitches, the resulting horizontal movements of the pivots of the rear ends of the links to the steering frame are at least substantially equal to each other.