Hydraulic percussion device

Abstract

The invention relates to a hydraulic percussion device intended to be fitted on a base vehicle, the device comprising: a housing comprising a closing plate; a power cell mounted in the housing; and a damper connecting the power cell and the closing plate, the damper comprising a body rigidly connected to the power cell opposite the closing plate; a chamber provided inside the body; and a closing piston which is movable inside the chamber and capable of abutting against the closing plate in order to seal the chamber, the chamber being intended to contain a compressible fluid for damping the movements of the power cell in relation to the housing.

Claims

1. A hydraulic percussion device intended to be installed on a carrier machine, the device comprising: a housing comprising a closing plate, a power cell mounted in the housing and movable in translation relative to said housing; said power cell comprising an impact piston that is movable in translation by two opposing annular chambers alternately supplied by fluid under pressure, and a damper connecting the power cell and the closing plate in such a way as to transmit the displacement forces applied on the housing to the power cell, wherein the damper comprises: a body rigidly connected to the power cell opposite the closing plate, said body being immobile relative to said power cell, a chamber provided inside the body, and a closing piston which is movable inside the chamber and relative to said power cell and capable of abutting against the closing plate in order to seal the chamber, said closing piston being pressed against said closing plate when said chamber is under pressure, the chamber being intended to contain a compressible fluid for damping the movements of the power cell in relation to the housing.

2. The device according to claim 1, wherein at least one portion of the impact piston is intended to penetrate into the chamber in such a way that, when the chamber contains a compressible fluid, the displacement of the impact piston inside the chamber is capable of compressing the compressible fluid, and the decompression of the compressible fluid is capable of displacing the impact piston.

3. The device according to claim 1, wherein the power cell is connected to a pressure accumulator comprising a hydraulic circuit and a pneumatic circuit separated by a deformable membrane, the chamber is in pneumatic communication with the pneumatic circuit of the pressure accumulator so that the pressure contained in the hydraulic circuit is transmitted to the chamber by means of the membrane.

4. The device according to claim 1, wherein the power cell being sealed by a cover, the body comprising the chamber is mounted on said cover.

5. The device according to claim 1, wherein the closing piston comprises: a body, intended to ensure the sealing of the chamber, and, a head, intended to ensure that the closing piston is maintained against the closing plate.

6. The device according to claim 5, wherein the body of the closing piston comprises a groove containing a gasket appropriate for the diameter of the chamber and for an expected pressure in the chamber.

7. The device according to claim 1, wherein the chamber is intended to contain nitrogen in gaseous form.

8. The device according to claim 1, further comprising an element for rigidly attaching the housing to the closing plate, the element being intended to attach the housing to a carrier machine.

9. The device according to claim 1, further comprising an attachment element positioned on the housing in an area away from the closing plate, the attachment element being intended to attach the housing to a carrier machine.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The way to achieve the invention as well as the advantages deriving therefrom will be clearly seen from the following embodiment, provided by way of non-limiting example, as a function of the appended figures in which FIGS. 1 to 6 represent:

(2) FIG. 1, state of the art: a schematic representation in perspective of a carrier machine equipped with a hydraulic percussion device;

(3) FIG. 2, state of the art: a schematic representation in cross-section of the hydraulic percussion device of FIG. 1;

(4) FIG. 3: a schematic representation in cross-section of a hydraulic percussion device according to a first embodiment of the invention;

(5) FIG. 4: a schematic representation in cross-section of a hydraulic percussion device according to a second embodiment of the invention;

(6) FIG. 5: a schematic representation in perspective of the hydraulic percussion device of FIG. 4;

(7) FIG. 6: a schematic representation in perspective of a power cell according to the embodiment of FIG. 4; and

(8) FIG. 7: a schematic representation in cross-section of a hydraulic percussion device according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(9) In the description, the hydraulic percussion device 10a, 10b, 10c is described assuming that it is positioned in its most common configuration, namely vertically, i.e. with the tool 19 oriented vertically in contact with a surface to be destroyed, as illustrated in FIG. 1.

(10) FIG. 3 illustrates a hydraulic percussion device 10a comprising a housing supporting a power cell 14. The power cell 14 is substantially cylindrical or parallelepiped in shape, sealed by a cover 32. The power cell 14 is mounted inside the housing 15 between a damper 28, guide means 29 and a stop 25. A U-shaped attachment plate 16 is disposed on the side of the housing 15 to attach the housing to the arm 12 of a carrier machine 11. As a variant, as described in FIGS. 4 to 7, the attachment plate 16 can be disposed on the upper part of the housing 15.

(11) The housing 15 comprises a closing plate 20a attached to the uprights surrounding the power cell 14. The damper 28 is positioned between said closing plate 20a and the cover 32 of the power cell 14. Said damper 28 comprises a body 27 rigidly connected to the power cell 14 opposite the closing plate 20a. By rigidly connected, it is understood that the body 27 is attached directly or indirectly to the power cell 14. A chamber 22 is provided inside the body 27, and a closing piston 30 is mounted movable in translation in the chamber 22. The body 27 and the chamber 22 are preferably cylindrical. The closing piston 30 is dimensioned to ensure the seal of the chamber 22. For example, as illustrated in FIG. 3, the closing piston 30 can comprise a body 44 and a head 45 that are cylindrical. The diameter of the body 44 is adapted to the diameter of the chamber 22 so as to ensure the seal of the chamber 22. Preferably, the body 44 comprises a groove containing a gasket 43 suitable for the diameter of the chamber 22.

(12) The chamber 22 is intended to contain a compressible fluid, for example nitrogen in gaseous form. The head 45 of the closing piston 30 is pressed against the closing plate 20a when the chamber 22 is under pressure. The compressible fluid is intended to dampen the movements of the power cell 14 relative to the housing 15, for example when a reflected shockwave is transmitted to the power cell 14 by the tool 19. The compressible fluid can also dampen the movements of the housing 15 relative to the power cell 14, for example when an abrupt movement of the tool 19 is controlled by the arm 12 of a carrier machine 11.

(13) In the first embodiment of FIG. 3, the impact piston 18 contained in the power cell 14 is movable in an actuation chamber different from the chamber 22 of the damper 28. In the second embodiment of FIGS. 4 to 6, the actuation chamber of the impact piston 18 and the chamber 22 of the damper 28 are achieved by a single through-bore in the power cell 14. The body 23 of the power cell 14 is combined with the body 27 of the damper 28. From bottom to top, the body 23 of the power cell 14 contains a portion of the tool 19, the impact piston 18 and a portion of the closing piston 30. These two elements are movable in the chamber 22 and extend longitudinally along the same axis X.

(14) The tool 19 comprises an upper end intended to receive impacts from the impact piston 18. The shockwave is propagated along the body of the tool 19 down to the lower end intended to come in contact with the surface S to be destroyed. The body of the tool 19 is preferably cylindrical with a flattened surface in which two retainer keys 17 are disposed. The retainer keys 17 are connected to the power cell 14 in such a way as to limit the rotational and translational movements of the tool 19. The retainer keys 17 also make it possible to maintain the tool 19 in the power cell 14 during movements of the hydraulic percussion device 10b and when the tool 19 is not in contact with a surface S to be destroyed. The arm 12 of a carrier machine 11 can also press down on the tool 19. To do this, the arm 12 moves the housing 15, thus causing a movement of the power cell 14. Bearing means 26 on the tool 19 are also secured in the body 23 of the power cell 14 at a beveled surface of the tool 19 so as to transmit the movements of the power cell 14 to the tool 19.

(15) The impact piston 18 is movable in the body 23 of the power cell 14 by means of two opposing annular chambers 37, 38 alternately supplied by fluid under pressure. The two chambers 37, 38 are controlled by a hydraulic control device 41. The power cell 14 also includes a compression chamber, containing a compressible gas, disposed above the impact piston 18. The compression chamber is combined with the chamber 22 of the damper 18. The same compressible gas, for example nitrogen, is used to carry out the function of the compression chamber and the function of the damper 18.

(16) When the hydraulic percussion device 10b is actuated, a first phase consists of moving the impact piston 18 in the chamber 22 by injection of a pressure into the lower annular chamber 38, thus compressing the gas in the chamber 22. A second phase consists of canceling the effect of the pressure in the lower annular chamber 38, by supplying the upper annular chamber 37 with the same pressure; thus, there is then nearly no force applied to the impact piston 18 by the annular chambers 37, 38. In a third phase, the compressible gas is expanded, and it violently moves the impact piston 18 downwards, impacting the tool 19 with sufficient force to break a rock.

(17) The damper 28 comprises a body 27 combined with the body 23 of the power cell 14 and a closing piston 30 movable in translation in the body 23. The closing piston 30 comprises a body 44 the diameter of which is adapted to the diameter of the chamber 22. Said body 44 is provided with an annular groove in which a gasket 43 is inserted, ensuring the seal of the chamber 22. The closing piston 30 comprises a head of one piece with the body 44. The head 45 is intended to come into contact with a closing plate 20b. The closing piston 30 thus makes it possible to effectively seal the chamber 22 and lock the power cell 14 in the housing 15.

(18) Preferably, the closing piston 30 is dimensioned in such a way that when the chamber 22 is under pressure, the pressure of the chamber 22 on the closing piston 30 is greater than the force of pressure of the arm 12 of the carrier machine 11 on the closing plate, irrespective of the position of the impact piston 18.

(19) In the example of FIGS. 4 to 6, the closing plate 20b is formed by the attachment plate 16 intended to be attached to the arm 12 of a carrier machine 11. The housing 15 comprises an attachment plate 21 intended to cooperate with the attachment plate 16 to attach the hydraulic percussion device 10b to the arm 12 of a carrier machine 11. The attachment plate 21 of the housing 15 comprises a central recess in which the head 45 of the closing piston 30 penetrates in order to enter into contact with the attachment plate 16.

(20) To assemble the hydraulic percussion device 10b, the tool 19, the impact piston 18 and the closing piston 30 are inserted successively into the body 23 of the power cell 14. After insertion of the tool 19, the retaining keys 17 are inserted to restrict the rotational and translational movements of the tool 19. The impact piston 18 is moved in the body 23 abutted against the tool 19, so that the chambers 37, 38 can control the movements of the impact piston 18. The closing piston 30 is then inserted into the body 23 above the impact piston 18. The attachment plate 21 of the housing 15 is attached to the attachment plate 16 intended to be attached to the arm 12 of a carrier machine 11. Finally, the gas is then introduced into the chamber 22 through a fluid intake 33, moving the closing piston 30 against the attachment plate 16.

(21) In the example of FIG. 7, a hydraulic percussion device 10c comprises an upper chamber 37 to control the impact piston 18, said chamber being disposed above the impact piston 18 in a pressure accumulator 51. The pressure accumulator 51 comprises a pneumatic circuit 53 disposed above the upper chamber 37. The pneumatic circuit 53 and the upper chamber 37 are connected by a deformable membrane 52 in such a way that the variations of pressure of the upper chamber 37 are absorbed by the pneumatic circuit 53 by means of the deformable member 52. The damper 28 is disposed on the pressure accumulator 51 and the chamber 22 of the damper 28 is in pneumatic communication with the pneumatic circuit 53 of the pressure accumulator 51 by means of a channel 54. Thus, the variations in pressure of the upper chamber 37 are absorbed both by the pneumatic circuit 53 and by the damper 28.

(22) It is clear from the foregoing that the hydraulic percussion devices 10a, 10b, 10c according to the invention have multiple advantages, particularly in terms of ease of assembly, compensation for manufacturing tolerances, and simplicity related to the elimination of the additional suspension device.