Abstract: In a method of regulating the supply of driving-medium per stroke cycle to a pile-driving rammer the driving-medium supply per stroke cycle is adjusted for driving piles into the ground in the shortest time in dependence upon the value, measured by at least one scanner, of the result of at least two preceding strokes of the rammer and more in accordance with the driving-medium supply adjusted during the stroke which gave the better result.In order to improve the energy transfer from a diesel hammer upon the pile apart from a basic fuel per combustion cycle at least one substance affecting the combustion velocity is supplied to the Diesel hammer in accordance with the pile-driving operation.

Abstract: A cylinder piece for a cylinder of a pile driving ram comprises inlet and outlet ports and at least two guide girdles for supporting guide members adapted to co-operate with a guide stay of a guide frame.This considerable cylinder piece can be readily made in such a way that the possibility of unexpected damage is reduced and that it has a long lifetime, in that a core of the cylinder piece is made from ferritic-perlitic nodular cast iron with at least two substantially cylindrical guide girdle faces for guide girdles and in that at least two guide girdles are clamped around the guide girdle faces, which guide girdles are each mainly formed by a ring from predominantly ferritic nodular cast iron with a cylindrical bore.

Abstract: A pile driving device comprises one or more guide stays, a Diesel hammer, consisting of a combustion cylinder guided by guide means along each guide stay and a hammer piston operating in said combustion cylinder.Lifting the hammer piston at the start of the known pile-driving device takes place by means of a cable of a winch arranged at a large distance. In order to facilitate the starting the hammer piston is lifted by means of a hydraulic cylinder-piston set which via a catch engages the piston on the one hand and the combustion cylinder on the other hand.

Abstract: In a Diesel pile-driving ram comprising a combustion cylinder, a striker extending into the combustion cylinder, a piston housed in the combustion cylinder and a fuel injector for the supply of fuel between the impact surfaces of the piston and the striker, the impact surface of the striker is orientated in such a manner towards an annular precombustion chamber of a compression space provided between the piston and the striker, that the fuel atomized by impact ignites in the precombustion chamber. Said fuel, however, has too little air in said chamber in order to ignite immediately. The ignition is delayed for a moment but not too strongly because the precombustion chamber communicates with the main combustion chamber through an ample, annular passage of short length in an axial direction.

Abstract: A pile-driving hammer comprises a hammer cylinder, a piston accomodated in said hammer cylinder in sealing relationship with a sliding face of the hammer cylinder and means for supplying lubricant to said sliding face which consists of a lining of wear-resistant material.The pile driving hammer has a long lifetime, since cavities are provided in the lining distributed along the surface of the sliding face. In this hammer the lubricant is retained in the cavities.

Abstract: In a rammer a piston housed in a combustion cylinder strikes with its impact surface the adapted impact surface of a striker. When the impact surfaces are spherical or flattened the piston may strike against the cylinder wall, as a result of which the cylinder surfaces and the piston surfaces wear off strongly. In accordance with the invention the impact surfaces have a tangential cone having an obtuse apex so that on the one hand a sufficient centering of the piston with respect to the striker is obtained and on the other hand the risk of cracking in piston and striker is prevented.

Abstract: A cylinder piece for use as the cylinder in a pile driving ram is provided with inlet and outlet ports and at least two guide girdles for supporting guide members adapted to cooperate with at least one guide stay of the guide frame. The core of the cylinder piece is made by forging and has at least two substantially cylindrical guide girdle faces for guide girdles, with the guide girdle being formed by a ring having a cylindrical bore being shrunk around a guide girdle face.

Abstract: The removal of a lining, for example of wood, from a pile driving head is a very difficult and time-consuming operation. In order to remove the lining easily from the pile driving head, at least one armature is embedded in the lining to be used in the pile driving head, said armature being provided with fastening means, and a tool is connected with the armature by means of said fastening means for removing the lining. When the lining is stroke down during the pile driving operation, the armature with at least part of the lining is drawn from the pile driving head by means of said energized tool supporting on the driving head and/or a further part of the lining.