Ram device
AssigneeN.V. Appingedammer Bronsmotorenfabriek
InventorJohann Daniel Meijer
Life of this patent
Estimating the term…
Abstract
A ram device has a drop hammer connected to the piston of a lifting cylinder which is connected by means of short and wide ducts to a control apparatus for admitting compressed air into the cylinder and for discharging the air from the cylinder beneath the piston, control apparatus directly communicating with the ambient air so as to allow a rapid escape of the air through large air vent ports from beneath the piston. In particular this control apparatus is directly mounted on the cylinder, or is included in an extension of this cylinder.
Claims7
A pile driving drop hammer comprising, in combination, a vertically oriented cylinder adapted to be mounted above a pile and having a bore and a cylinder wall;
- a piston movable in said bore;
- a drop weight connected to said piston and operable, when dropped, to ram ;he pile into the ground;
- a sleeve valve movable inside said cylinder and operable to cover and to block ports formed in said cylinder wall, said ports including a first set of ports communicating with a supply of pressurized air and a second set of ports communicating directly with the ambient external atmosphere, the ports of at least said second set being distributed around said cylinder wall and having a flow cross-section sufficiently large to offer only a minimal resistance to flow of air therethrough;
- said sets of ports being spaced apart from each other axially of said cylinder wall;
- piston means on said sleeve valve movable in a separate part of said cylinder sealingly separated from said bore in which said drop weight connected piston is movable;
- and control means selectively operable to connect said separate cylinder part to a source of pressurized air to subject said piston means to pressurized air to move said sleeve valve axially of said cylinder;
- the sleeve part of said sleeve valve having an axial length sufficiently greater than the axial spacing of said sets of ports that, upon axial movement of said sleeve valve, said sleeve part blocks communication between one set of ports and the interior of said cylinder bore beneath said drop weight connected piston before establishing communication between the other set of ports and the interior of said piston bore beneath said drop weight connected piston;
- said sleeve valve and said sets of ports being relatively arranged in a manner such that, upon establishing of communication between said first set of ports and the interior of said cylinder bore beneath said drop weight connected piston, following blocking of communication between said second set of ports and the interior of said cylinder bore beneath said drop weight connected piston, pressurized air is admitted through said sleeve valve to said cylinder bore beneath said drop weight connected piston to lift said drop weight connected piston and, upon establishment of communication between said second set of ports and the interior of said cylinder bore beneath said drop weight connected piston, following blocking of communication between said first set of ports and the interior of said cylinder bore beneath said drop weight connected piston, the pressurized air escapes directly to the ambient external atmosphere through said second set of ports with a minimum resistance to air flow, until said drop weight connected piston has dropped to its lowermost position to impact said drop weight against the pile to ram the pile into the ground.
Dependencies are inferred from the claim text.