Method and machine for altering the striking stroke of a percussive machine moved by a pressurized incompressible fluid
AssigneeEtablissements Montabert
InventorJean S. Comarmond
Life of this patent
Estimating the term…
Abstract
Method and apparatus for controlling a percussive machine by determining, during the phase of rebound of a piston following impact, the existence of an instantaneous flow rate of fluid flowing from a top chamber toward the high-pressure fluid feed circuit. The instantaneous flow rate is determined on the basis of the differential pressure between the top chamber and the high pressure fluid feed circuit. If a flow rate is detected, a control device is fed with pressurized fluid so as to shift a selector piston in a direction for lengthening the stroke of the striking piston.
Claims13
A device for altering the striking stroke of a percussive machine moved by a pressurized fluid, comprising:
- a piston movably located in a cylinder and defining a top chamber and bottom chamber;
- a stroke selector piston for varying the stroke of the piston;
- a distributor in communication with the top chamber, bottom chamber and the stroke selector piston;
- said stroke selector piston located in the cylinder and having a face subjectable to fluid pressure, said stroke selector piston having a groove communicating with the distributor and capable of being placed in communication with the bottom chamber when the piston approaches the top chamber.
A method for altering the striking stroke of a percussive machine moved by a pressurized fluid, comprising:
- providing a piston that travels inside a cylinder and delimits, with the cylinder, a top chamber and a bottom chamber;
- providing a distributor that sequentially feeds a high-pressure fluid to a stroke selector piston mounted in the cylinder, thus allowing the stroke of the piston to be varied;
- providing the stroke selector piston with at least one face subjectable to a fluid pressure and including a return device, said stroke selector piston having a groove that can communicate with the distributor;
- connecting the groove, depending on the axial position of the stroke selector piston, to one of a plurality of passages in the cylinder and communicating the groove with the bottom chamber when the piston approaches the top chamber;
- determining an instantaneous flow rate of fluid flowing out of the top chamber toward a high pressure fluid feed circuit during rebound of the piston following impact, the flow rate being determined on the basis of a differential pressure between the top chamber and the high pressure fluid feed circuit;
- feeding the stroke selector piston with pressurized fluid depending on the detected flow rate.
Dependencies are inferred from the claim text.