阅读说明：本技术 设置有与低压蓄能器永久连接的控制室的旋转冲击式液压穿孔器 (Rotary impact hydraulic perforator provided with a control chamber permanently connected to a low pressure accumulator ) 是由 让-西尔万·科马蒙德 于 2019-01-16 设计创作，主要内容包括：一种旋转冲击式液压钻孔器(2)包括主体(3)；配件(15)；击打活塞(5),其构造为击打配件(15)；冲击活塞(13),其具有面向配件(15)的前面(18)和面向腔体(14)的容纳冲击活塞的后壁(21)；以及包括高压流体供给管线(9)和低压流体回流管线(11)的主液压供给回路。主体(3)和冲击活塞(13)限定第一控制室(22),其永久连接到高压流体供给管线(9)并且构造为推动冲击活塞(13)向前,以及限定第二控制室(25),其构造为推动冲击活塞(13)向前并永久地与连接到低压流体回流管线(11)的低压蓄能器(26)连接。(A rotary percussion hydraulic drill (2) comprises a body (3); a fitting (15); a striking piston (5) configured as a striking fitting (15); an impact piston (13) having a front face (18) facing the fitting (15) and a rear wall (21) facing the cavity (14) housing the impact piston; and a main hydraulic supply circuit comprising a high pressure fluid supply line (9) and a low pressure fluid return line (11). The body (3) and the percussion piston (13) define a first control chamber (22) permanently connected to the high-pressure fluid supply line (9) and configured to push the percussion piston (13) forward, and a second control chamber (25) configured to push the percussion piston (13) forward and permanently connected with a low-pressure accumulator (26) connected to the low-pressure fluid return line (11).)

1. A rotary impact hydraulic perforator (2) comprising:

-a main body (3),

-a fitting (15) for coupling to at least one drill rod equipped with a tool,

-a striking piston (5) slidably mounted in the body (3) along a striking axis (A) and configured to strike the accessory (15),

-a catch piston (13) slidably mounted in a cavity (14) of the body (3) along a displacement axis substantially parallel to the striking axis (a), the catch piston (13) comprising a front face (18) facing the fitting (15) and serving to position the fitting (15) in a predetermined rest position with respect to the striking piston (5), and a rear face (19) opposite the front face (18) and located opposite a rear wall (21) of the cavity (14), and

-a main hydraulic supply circuit configured to control the alternating sliding of the striking piston (5) along the striking axis (A) and to control the sliding of the catch piston (13) along the displacement axis, the main hydraulic supply circuit comprising a high pressure fluid supply conduit (9) and a low pressure fluid return conduit (11),

the body (3) and the stop piston (13) delimiting at least partially a first control chamber (22) permanently connected to the high-pressure fluid supply conduit (9) and configured to bias the stop piston (13) forward, the rotary impact hydraulic perforator (2) further comprising a connecting channel (33) configured to fluidly connect the first control chamber (22) to the low-pressure fluid return conduit (11) when the rear face (19) of the stop piston (13) is located at a distance greater than a predetermined value from the rear wall (21) of the cavity (14),

characterized in that the main hydraulic supply circuit further comprises a low pressure accumulator (26) connected to the low pressure fluid return conduit (11), and in that the body (3) and the catch piston (13) further delimit at least partially a second control chamber (25) permanently connected to the low pressure accumulator (26) and configured to bias the catch piston (13) forward.

2. A rotary impact hydraulic perforator (2) according to claim 1, wherein the stopper piston (13) comprises a first annular control surface (28) extending transverse to the displacement axis and at least partially delimiting the first control chamber (22) and a second annular control surface (29) extending transverse to the displacement axis and at least partially delimiting the second control chamber (25), the second annular control surface (29) having a surface area larger than a surface area of the first annular control surface (28).

3. A rotary impact hydraulic perforator (2) according to claim 1 or 2, wherein the body (3) and the stopper piston (13) further at least partly delimit a third control chamber (31) permanently connected to the low pressure fluid return conduit (11), the third control chamber (31) being located opposite the first and second control chambers (22, 25).

4. A rotary impact hydraulic perforator (2) according to claim 3, wherein the third control chamber (31) is connected to the low pressure fluid return conduit (11) through a fluid communication channel (32) provided with calibrated holes (42).

5. A rotary impact hydraulic perforator (2) according to claim 3 or 4, wherein the stopper piston (13) comprises the connection channel (33) and the connection channel (33) comprises a first end portion (33.1) opening into the third control chamber (31) and a second end portion (33.2) opposite the first end portion (33.1) and opening into the outer surface of the stopper piston (13), the second end portion (33.2) of the connection channel (33) being fluidly connectable to the first control chamber (22) when the rear face (19) of the stopper piston (13) is located at a distance from the rear wall (21) of the cavity (14) which is larger than the predetermined value.

6. A rotary impact hydraulic perforator (2) according to any of claims 1 to 4, wherein the stopper piston (13) comprises the connection channel (33).

7. A rotary impact hydraulic perforator (2) according to claim 6, wherein the connection channel (33) comprises a first end portion (33.1) opening into the first control chamber (22) and a second end portion (33.2) opposite the first end portion (33.1) and opening into the outer surface of the stopper piston (13), the second end portion (33.2) of the connection channel (33) being fluidly connectable to the low pressure fluid return conduit (11) when the rear face (19) of the stopper piston (13) is located at a distance from the rear wall (21) of the cavity (14) which is larger than the predetermined value.

8. A rotary impact hydraulic perforator (2) according to claim 7, wherein the body (3) has an annular groove (34) opening into the cavity (14) and permanently connected to the low pressure fluid return conduit (11), the second end portion (33.2) of the connection channel (33) being fluidly connectable to the annular groove (34) when the rear face (19) of the stopper piston (13) is located at a distance from the rear wall (21) of the cavity (14) which is larger than the predetermined value.

9. The rotary impact hydraulic perforator (2) according to any one of claims 1 to 8, comprising a supply channel (23) connecting the first control chamber (22) to the high pressure fluid supply conduit (9).

10. A rotary impact hydraulic perforator (2) according to claim 9, wherein the feed channel (23) is provided with calibrated holes (24).

11. A rotary impact hydraulic perforator (2) according to any of claims 1 to 10, wherein the stopper piston (13) is slidably mounted around the striking piston (5).

12. A rotary impact hydraulic perforator (2) according to any of claims 1 to 11, wherein the main hydraulic supply circuit comprises a high pressure accumulator (12) connected to the high pressure fluid supply conduit (9).

13. A rotary impact hydraulic perforator (2) according to any of claims 1 to 12, further comprising an annular stop member (38) arranged between the fitting (15) and the front face (18) of the stop piston (13).

14. A rotary impact hydraulic perforator (2) according to any of claims 1 to 13 comprising a thrust bearing (44) arranged between the rear face (19) of the stopper piston (13) and the rear wall (21) of the cavity (14).

15. A rotary impact hydraulic perforator (2) according to any of claims 1 to 14, wherein the stopper piston (13) comprises an annular bearing surface (39) configured to abut against an annular stopper surface (41) of the body (3).

Technical Field

The present invention relates to rotary impact hydraulic perforators, and more particularly, to rotary impact hydraulic perforators for use on drilling units.

Background

The drilling rig unit comprises in a known manner: a rotary percussion hydraulic perforator, which is slidably mounted on a slide and drives one or more drill rods, the last of which carries a tool called a drill bit, which is in contact with the rock. The purpose of such perforators is typically to drill or drill deep or shallow holes in order to be able to place explosives therein. Thus, a perforator is an essential element of a drilling unit which on the one hand imparts rotation and impact to the drill bit through the drill rod to penetrate the rock and on the other hand provides injection of fluid to extract debris from the drill hole.

The rotary impact hydraulic perforator more particularly comprises, on the one hand, a striking system driven by one or more flows of hydraulic fluid from a main hydraulic supply circuit, the striking system comprising a striking piston configured to strike a fitting coupled to the drill rod at each operating cycle of the perforator, and on the other hand, a rotation system provided with a hydraulic rotation motor and configured to rotate the fitting and the drill rod.

Due to the cable or the drive chain, which is moved by means of a hydraulic cylinder or a hydraulic motor, the bearing force of the rotating percussion hydraulic perforator on the drill rod, and thus the bearing force of the drill bit on the rock, is generated by the slide. More specifically, the bearing force is transmitted from the body of the perforator to the fitting via a stop element incorporated in the body of the perforator. For a power perforator, the stop element may be constituted by a stop piston, at least one surface of which is hydraulically supplied to ensure transmission of the bearing force by the fluid.

The stability and penetration speed performance of a rotary impact hydraulic perforator in operation depend inter alia on the way in which the stopper piston is arranged and hydraulically fed in the rotary impact hydraulic perforator.

Document WO2010/082871 discloses a rotary impact hydraulic perforator in which, in the operating conditions of the punching system, a stop piston is positioned in a balanced position according to the desired striking stroke of the striking piston by means of a hydraulic control chamber delimited by the striking piston and the body of the perforator and permanently connected to a high pressure fluid supply conduit, the hydraulic control chamber being configured to bias the stop piston forward on the one hand, and to be connected to a low pressure fluid return conduit on the other hand when the rear face of the stop piston is located at a predetermined distance from the rear wall of the cavity receiving the stop piston.

The configuration of the catch piston and the body described in document WO2010/082871 enables a substantially stable positioning of the catch piston to be ensured during operation of the striking system.

However, the vibrations and reactions of the repeated impacts of the rock on the drill bit make the bearing force of the tool of the drill rod unstable on the rock, in particular during the movement of the tool, due to the penetration of the drill rod in the ground and to the various vibrations of the body of the perforator. However, this instability of the bearing force of the drill bit on the rock affects the positioning of the fitting relative to the striking piston and thus the performance of the hydraulic perforator.

The present invention aims to remedy all or part of these disadvantages.

Disclosure of Invention

The technical problem underlying the present invention therefore consists in providing a hydraulic perforator that is structurally simple and economical, with improved performance.

To this end, the invention relates to a rotary impact hydraulic perforator comprising:

-a main body,

-a fitting for coupling to at least one drill rod equipped with a tool,

a striking piston slidably mounted in the body along a striking axis and configured as a striking accessory,

a catch piston which is tubular and is slidably mounted in the body cavity along a displacement axis substantially parallel to the striking axis, the catch piston comprising a front face facing the fitting and serving to position the fitting in a predetermined equilibrium position with respect to the striking piston, and a rear face opposite the front face and located opposite the rear wall of the cavity, and

-a main hydraulic supply circuit configured to control the alternating sliding of the striking piston along the striking axis and to control the sliding of the catch piston along the displacement axis, the main hydraulic supply circuit comprising a high pressure fluid supply conduit and a low pressure fluid return conduit,

the body and the stopper piston at least partially defining a first control chamber permanently connected to the high pressure fluid supply conduit and configured to bias the stopper piston forward, that is, toward the fitting and thus opposite the back wall of the cavity, the rotary impact hydraulic perforator further comprising a connecting channel configured to fluidly connect the first control chamber to the low pressure fluid return conduit when the back surface of the stopper piston is located at a distance from the back wall of the cavity greater than a predetermined value,

wherein the main hydraulic supply circuit further comprises a low pressure accumulator connected to the low pressure fluid return conduit, and wherein the body and the catch piston further at least partially define a second control chamber permanently connected to the low pressure accumulator and configured to bias the catch piston forward.

Due to the permanent connection of the second control chamber with the low pressure accumulator, this configuration of the second control chamber enables a high speed displacement of the stop piston forward to be ensured when the rock buckles under the impact of the striking piston and the fitting is suddenly free to move forward. This allows to quickly restore the normal bearing force of the tool of the drill rod on the rock, despite the movements due to the various vibrations of the drill rod penetrating into the ground and the body of the perforator.

Furthermore, the specific configuration of the first control chamber and the connecting channel makes it possible to hydraulically position the catch piston in a substantially stable equilibrium position corresponding to an optimal striking stroke of the striking piston.

Thus, the particular configuration of the rotary impact hydraulic perforator according to the present invention imparts improved performance relative to prior art rotary impact hydraulic perforators.

The hydraulic perforator may also have one or more of the following features, alone or in combination.

According to an embodiment of the invention, the low pressure accumulator is a diaphragm accumulator, e.g. a hydropneumatic accumulator. The diaphragm accumulator advantageously comprises a flexible diaphragm, a first side of which is subjected to the pressure of a volume of compressible gas contained in the diaphragm accumulator and a second side of which is subjected to the pressure of the low-pressure fluid from the low-pressure fluid return conduit.

According to an embodiment of the invention, the second control chamber is connected to the low pressure accumulator via a return channel.

According to an embodiment of the invention, the catch piston comprises a first annular control surface extending transversely to the displacement axis and at least partially delimiting the first control chamber, and a second annular control surface extending transversely to the displacement axis and at least partially delimiting the second control chamber, the second annular control surface having a surface area which is larger than a surface area of the first annular control surface.

According to an embodiment of the invention, the first control chamber has a cross section which is smaller than a cross section of the second control chamber.

According to an embodiment of the invention, each of the first and second annular control surfaces extends substantially perpendicular to the displacement axis.

According to an embodiment of the invention, the first annular control surface is closer to the front of the catch piston than the second annular control surface.

According to an embodiment of the invention, the body and the catch piston at least partially define a third control chamber permanently connected to the low pressure fluid return conduit, the third control chamber being disposed opposite the first and second control chambers.

According to an embodiment of the invention, the third control chamber is permanently connected to the low pressure accumulator.

According to an embodiment of the invention, the third control chamber is configured to bias the catch piston backwards, that is to say towards the rear wall of the cavity, and thus opposite the fitting.

According to an embodiment of the invention, the third control chamber is connected to the low pressure fluid return conduit by a fluid communication channel provided with a calibrated orifice.

According to an embodiment of the invention, the return channel comprises a spray nozzle comprising said calibrated holes.

According to an embodiment of the invention, the third control chamber has a cross-section which is smaller than the cross-section of the second control chamber.

According to an embodiment of the invention, the catch piston comprises a connecting channel, and said connecting channel comprises a first end portion open to the third control chamber and a second end portion opposite the first end portion and open to an outer surface of the catch piston, the second end portion being fluidly connectable to the first control chamber when the rear face of the catch piston is located at a distance from the rear wall of the cavity which is greater than a predetermined value.

According to an embodiment of the invention, the catch piston comprises a connecting channel.

According to an embodiment of the invention, the connection channel comprises a first end portion open to the first control chamber and a second end portion opposite the first end portion and open to the outer surface of the catch piston, the second end portion of the connection channel being fluidly connectable to the low pressure fluid return conduit when the rear face of the catch piston is located at a predetermined distance from the rear wall of the upper chamber body.

According to an embodiment of the invention, the body comprises an annular groove open to the cavity and permanently connected to the low-pressure fluid return conduit, the second end portion of the connection channel being fluidly connectable to the annular groove when the rear face of the catch piston is located at a distance greater than a predetermined value from the rear wall of the cavity.

According to an embodiment of the invention, the annular groove is connected to a low pressure accumulator.

According to an embodiment of the invention, the rotary impact hydraulic perforator comprises a supply channel connecting the first control chamber to a high pressure fluid supply conduit.

According to an embodiment of the invention, the supply channel is provided with a calibrated hole.

According to an embodiment of the invention, the supply channel comprises a spray nozzle comprising a calibrated orifice.

According to an embodiment of the invention, the catch piston is slidably mounted around the striking piston.

According to an embodiment of the invention, the main hydraulic supply circuit comprises a high pressure accumulator connected to the high pressure fluid supply conduit.

According to an embodiment of the invention, the high pressure accumulator is a diaphragm accumulator, e.g. a hydropneumatic accumulator. The diaphragm accumulator forming the high pressure accumulator advantageously comprises a flexible membrane, a first side of which is subjected to the pressure of the volume of compressible gas contained in the diaphragm accumulator and a second side of which is subjected to the pressure of the high pressure fluid coming from the high pressure fluid supply conduit.

According to an embodiment of the invention, the rotary impact hydraulic perforator further comprises an annular stop member arranged between the fitting and a front face of the stop piston.

According to an embodiment of the invention, the annular stop member is a stop ring.

According to an embodiment of the invention, the rotary impact hydraulic perforator comprises a thrust bearing arranged between a rear face of the stopper piston and a rear wall of the cavity. The thrust bearing may be, for example, a roller thrust bearing.

According to an embodiment of the invention, the stop piston comprises an annular bearing surface configured to abut against the annular stop surface of the body.

According to an embodiment of the invention, the annular bearing surface is configured to abut against the annular stop surface of the body when the rear face of the stop piston is located at a predetermined distance from the rear wall of the cavity, the predetermined distance being greater than a predetermined value.

According to an embodiment of the invention, the annular bearing surface is inclined with respect to the displacement axis.

According to an embodiment of the invention, the catch piston comprises an annular flange comprising an annular bearing surface.

According to an embodiment of the invention, the annular flange at least partially delimits the third control chamber.

According to an embodiment of the invention, the annular flange comprises a first annular control surface.

According to an embodiment of the invention, the body comprises a piston cylinder in which the striking piston is alternately slidably mounted, the cavity being formed in the body coaxially with the piston cylinder.

According to an embodiment of the invention, the fitting extends longitudinally along the striking axis.

According to an embodiment of the invention, the fitting comprises a first end portion facing the striking piston and provided with an end face against which the striking piston is intended to strike, and a second end portion opposite the first end portion for coupling to at least one drill rod.

According to an embodiment of the invention, the high pressure fluid supply conduit is a high pressure incompressible fluid supply conduit and the low pressure fluid return conduit is a low pressure incompressible fluid return conduit.

Drawings

In any case, the invention will be clearly understood by means of the following description, with reference, by way of non-limiting example, to the attached schematic drawings showing several embodiments of the hydraulic perforator.

Figure 1 is a longitudinal cross-sectional view of a rotary impact hydraulic perforator in accordance with a first embodiment of the present invention;

FIG. 2 is a longitudinal cross-sectional view of the detail of FIG. 1, at an enlarged scale;

figure 3 is a longitudinal cross-sectional view of a rotary impact hydraulic perforator in accordance with a second embodiment of the present invention;

figure 4 is a longitudinal cross-sectional view of a rotary impact hydraulic perforator according to a third embodiment of the present invention.

Detailed Description

Figures 1 and 2 show a first embodiment of a rotary impact hydraulic perforator 2 intended for perforating blast holes and provided in particular with a striking system and a rotating system.

The rotary impact hydraulic perforator 2 more specifically comprises a body 3 with a piston cylinder 4. According to the embodiment shown in fig. 1 and 2, the body 1 comprises a primary body 3.1 partially delimiting the piston cylinder 4, and a front bushing 3.2 and a rear bushing 3.3, which are effectively mounted in a hole 3.4 delimited by the primary body 3.1.

The striking system of the rotary impact hydraulic perforator 2 comprises a striking piston 5 slidably mounted alternately in a piston cylinder 4 along a striking axis a. As shown more particularly in fig. 2, the striking piston 5 and the piston cylinder 4 delimit annular primary control chambers 6 and 7, which have a cross section greater than that of the primary control chambers 6 and are arranged opposite the primary control chambers 6.

The striking system of the rotary impact hydraulic perforator 2 further comprises a control distributor 8 arranged to control the alternating movement of the striking piston 5 within the piston cylinder 4 alternately along the striking stroke and the return stroke. The control distributor 8 is configured to associate the secondary control chamber 7 alternately with a high pressure fluid supply conduit 9, e.g. a high pressure incompressible fluid supply conduit, during the striking stroke of the striking piston 5, and with a low pressure fluid return conduit 11, e.g. a low pressure incompressible fluid return conduit, during the return stroke of the striking piston 5. The high pressure fluid supply conduit 9 and the low pressure fluid return conduit 11 belong to the main hydraulic supply circuit provided with the blow system. The main hydraulic supply circuit may advantageously comprise a high pressure accumulator 12 connected to the high pressure fluid supply conduit 9.

More specifically, the control distributor 8 is movably mounted in a hole formed in the body 3 between a first position (see fig. 2) in which the control distributor 8 is configured to associate the secondary control chamber 7 with the high-pressure fluid supply conduit 9, and a second position in which the control conduit 8 is configured to associate the secondary control chamber 7 with the low-pressure fluid return conduit 11.

The primary control chamber 6 is advantageously permanently supplied with high-pressure fluid through a supply channel (not shown in the figures) so that each position of the control distributor 8 causes a striking stroke of the striking piston 5, followed by a return stroke of the striking piston 5.

The striking system of the rotary impact hydraulic perforator 2 further comprises a stop piston 13 which is tubular and which is slidably mounted in a cavity 14 of the body 3 along a displacement axis parallel to and preferably coincident with the striking axis a. According to the embodiment shown in fig. 1 and 2, the catch piston 13 is slidably mounted around the striking piston 5, and a cavity 14 is formed in the body 3 coaxially with the piston cylinder 4.

The rotary impact hydraulic perforator 2 further comprises a fitting 15 for coupling to at least one drill rod (not shown in the figures) equipped with a tool in a known manner. The fitting 15 extends longitudinally along a striking axis a and comprises a first end portion 16 facing the striking piston 5 and provided with an end face 17, the striking piston 5 being intended to strike said end face during each operating cycle of the rotary impact hydraulic perforator 2, and a second end portion 17 (not shown in the figures) opposite the first end portion 16 for coupling to at least one drill rod.

As shown more particularly in fig. 2, the catch piston 13 comprises a front face 18 facing the fitting 15 and serving to position the fitting 15 in a predetermined equilibrium position with respect to the striking piston 5, and a rear face 19 opposite said front face 18 and located opposite the rear wall 21 of the cavity 14.

The body 3 and the catch piston 13 delimit, together with the striking piston 5, a first control chamber 22, which is permanently connected to the high-pressure fluid supply conduit 9 and is configured to bias the catch piston 13 forward, that is to say towards the fitting 15 and thus away from the rear wall 21 of the cavity 14. The rotary impact hydraulic perforator 2 advantageously comprises a supply channel 23 connecting the first control chamber 22 to the high pressure fluid supply conduit 9. According to a first embodiment, shown in fig. 1 and 2, the supply channel 23 is provided with a calibrated hole 24, which may be provided, for example, on a spray nozzle incorporated in the supply channel 23.

The body 3 and the catch piston 13 together with the striking piston 5 also delimit a second control chamber 25, which is connected to a low-pressure accumulator 26, which belongs to the main hydraulic supply circuit of the striking system and which is connected to the low-pressure fluid return conduit 11. Like the first control chamber 22, the second control chamber 25 is also configured to bias the catch piston 13 forward. Advantageously, the rotary impact hydraulic perforator 2 comprises a return channel 27 connecting the second control chamber 25 to the low pressure accumulator 26.

According to the embodiment shown in fig. 1 and 2, the catch piston 13 comprises: a first annular control surface 28 (also referred to as a first annular effective surface) extending perpendicular to the displacement axis and partially defining the first control chamber 22; and a second annular control surface 29 (also called second annular active surface) extending perpendicular to the displacement axis and partially delimiting the second control chamber 25. The second annular control surface 29 advantageously has a surface area that is greater than the surface area of the first annular control surface 28. In other words, the second control chamber 25 advantageously has a cross section that is greater than the cross section of the first control chamber 22.

The body 3 and the catch piston 15 also delimit the third control chamber 31 permanently connected to the low pressure fluid return conduit 11 by means of a fluid communication channel 32 leading to the third control chamber 31 and a return channel 27 connecting the fluid communication channel 32 to the low pressure fluid return conduit 11. The third control chamber 31 is disposed opposite the first and second control chambers 22, 25 and is therefore configured to bias the check piston 13 rearward.

Advantageously, the second control chamber 25 is dimensioned to have an effective surface on the catch piston 13 that is much larger than the effective surface of the third control chamber 31. The second and third control chambers 25, 31 are connected to the return channel 27 and to the low pressure accumulator 26, the calculation of the difference of the two effective surfaces of the second and third control chambers 25, 31 giving the resulting effective surface that pushes the stop piston 13 forward and bears the pressure of the low pressure accumulator 26.

The rotary impact hydraulic perforator 2 further comprises a connection channel 33 configured to fluidly connect the first control chamber 22 to the low pressure fluid return conduit 11 when the back face 19 of the stopper piston 13 is located at a distance from the back wall 21 of the cavity 14 that is larger than a predetermined value. According to a first embodiment, shown in fig. 1 and 2, the catch piston 13 comprises a connecting channel 33, and said connecting channel 33 comprises a first end portion 33.1 opening into the first control chamber 22 and a second end portion 33.2 opposite the first end portion 33.1 and opening into the outer surface of the catch piston 13. Advantageously, when the rear face 19 of the catch piston 13 is located at a distance from the rear wall 21 of the cavity 14 greater than a predetermined value, the second end portion 33.2 of the connecting channel 33 can be fluidly connected to the annular groove 34 leading to the cavity 14 and permanently connected to the low-pressure fluid return conduit 11.

When the striking system of the rotary impact hydraulic perforator 2 is supplied, the pressure built up in the first control chamber 22 biases the stop piston 13 forward up to a position where the connecting channel 33 opens up to the annular groove 34 permanently connected to the low pressure fluid return conduit 11, due to the oil flow that has passed through the calibrated hole 24. At this point, the stop piston 13 (which is subjected to the force of the rock acting against the thrust exerted by the rotary impact hydraulic perforator 2) stops moving forward and finds an equilibrium position on the edge of the outlet of the connecting channel 33 in the annular groove 34. By construction, this equilibrium position makes it possible to position the fitting 15 at a distance from the striking piston 5 that corresponds to the striking stroke C provided for the striking piston 5. It should be noted that the calibrated orifice 24 advantageously has a very small size with respect to the connection channel 33 and the return channel 27, so that the pressure built up in the first control chamber 22 drops very quickly when the connection channel 33 opens in the annular groove 34. Furthermore, the flow rate through the calibrated orifice 24 should preferably be kept low, since it is taken from the high-pressure fluid supply conduit 9.

As described above, the flow rate of the fluid supplied to the first control chamber 22 is low, and therefore the displacement speed of the stopper piston 13 due to the flow rate of the fluid is also low. At the same time, the second control chamber 25 is freely fed by the low pressure accumulator 26 and will enable the catch piston 13 to be pushed at high speed, for example when rock collapses under the impact of the striking piston 5 and the fitting 15 is suddenly free to move forward. This enables a quick recovery of the normal bearing force of the tool of the drill rod on the rock despite the movements caused by the drill rod penetrating the ground and the various vibrations of the body 3 of the perforator, while ensuring an average position of the catch piston 13 due to the first control chamber 22, which follows the provided striking stroke C of the striking piston 5.

The rotary impact hydraulic perforator 2 further comprises a rotation system comprising a hydraulic motor 35 driving a drive pinion 36 and a receiving pinion 37 to ensure the rotational movement of the fitting 15. The hydraulic motor 35 is advantageously hydraulically fed by an external hydraulic feed circuit.

When the rotary impact hydraulic perforator 2 is in operation, the fitting 15 is rotated by the hydraulic motor 35 and the fitting 15 receives on its end face 17 periodic impacts of the striking piston 5, which is ensured by the striking system fed by the main hydraulic supply circuit. At the same time, the carrier on which the rotary impact hydraulic perforator 2 is mounted exerts a thrust on the drill rod through the body 3 and the fitting 15 of the rotary impact hydraulic perforator 2. Inside the perforator, between the body 3 and the fitting 15, this force is transmitted through the stopper piston 13 and a stopper member 38 (e.g. a stopper ring) arranged between the fitting 15 and the front face 18 of the stopper piston 13. The positioning of the catch piston 13 is thus purely hydraulic and arranged such that the striking stroke C of the striking piston 5 is followed.

The catch piston 13 further comprises an annular bearing surface 39 configured to abut against an annular catch surface 41 of the body 3 to limit the forward displacement stroke of the catch piston 13, that is to say towards the fitting 15. Advantageously, the annular bearing surface 39 is configured to abut against an annular stop surface 41 of the body 3 when the rear face 19 of the stop piston 13 is located at a predetermined distance from the rear wall 21 of the cavity 14, the predetermined distance being greater than a predetermined value. According to the first embodiment of the invention, the annular bearing surface 39 is inclined with respect to the axis of displacement and partially delimits the third control chamber 31.

Fig. 3 shows a second embodiment of a rotary impact hydraulic perforator 2, which essentially differs from the first embodiment in that the fluid communication channel 32 is provided with a calibrated hole 42, which may for example be provided on an injection nozzle coupled to the fluid communication channel 32, and wherein a first end portion 33.1 of the connection channel 33 opens into the third control chamber 31 and a second end portion 33.2 of the connection channel 33 opens into the outer surface of the stopper piston 13, the second end portion 33.2 of the connection channel 33 being fluidly connectable to the first control chamber 22 when the rear face 19 of the stopper piston 13 is located at a distance from the rear wall 21 of the cavity 14 which is larger than a predetermined value.

When the rotary impact hydraulic perforator 2 according to the second embodiment of the present invention is operated, the first control chamber 22 is subjected to high pressure and the stopper piston 13 is displaced forward until the second end portion 33.2 of the connection channel 33 is opened in the first control chamber 22. Then, the oil at high pressure flows into the third control chamber 31, the connection of which to the return channel 27 is throttled by the calibrated orifice 42. The first and third control chambers 22, 31 are then subjected to relatively close pressures which reduce or counteract the forward thrust of the catch piston 13. The catch piston 13 will thus find a stable operating position around this position of the second end portion 33.2 of the connecting channel 33.

As in the first embodiment of the invention, the second control chamber 25 is freely fed by the low pressure accumulator 26 and will allow the catch piston 13 to be pushed forward at high speed, for example when a rock collapses under the impact of the striking piston 5. This allows a quick return to the normal bearing force of the drill rod tool on the rock despite the movements due to the penetration of the drill rod into the ground and the various vibrations of the body 3 of the perforator, while at the same time an average position of the catch piston 13 is ensured due to the first and third control chambers 22, 31, which follows the provided striking stroke C of the striking piston 5.

According to a second embodiment of the invention, the catch piston 13 comprises an annular flange 43 (also called annular shoulder) comprising the annular bearing surface 39 and the first annular control surface 28. Thus, the annular flange 43 advantageously partially delimits the first control chamber 22 and partially delimits the third control chamber 31.

According to a second embodiment of the invention, the feed channel 23 is advantageously free of calibrated holes, or of any other specific throttling element.

Figure 4 shows a third embodiment of the rotary impact hydraulic perforator 2, which essentially differs from the first embodiment in that the rotary impact hydraulic perforator 2 comprises a thrust bearing 44 (e.g. a roller thrust bearing) arranged between the rear face 19 of the stopper piston 13 and the rear wall 21 of the | cavity 14.

When the striking system of the rotary impact hydraulic perforator 2 is not supplied and the rotation system of the rotary impact hydraulic perforator is in operation, the fitting 15 is rotating as well as the stop member 38 and the stop piston 13. Since the positioning of the catch piston 13 in the predetermined equilibrium position is only achieved when the percussion system is running (thus providing the necessary fluid in the first, second and third control chambers 22, 25, 31), then the catch piston 13 is pressed by the reaction force of the ground, not against the rear wall 21 of the cavity 14 (which may cause rotational friction of the catch piston 13 with respect to the body 3 and thus damage to the different components of the perforator), but against the thrust bearing 44 (which greatly limits the wear of the rotary percussion hydraulic perforator 2 and which does not require the addition of external fluid at the level of the catch piston 13).

It goes without saying that the invention is not limited solely to the embodiment of such a hydraulic perforator described above by way of example, but, on the contrary, it includes all its variants.