Hydraulic rotary impact hammer drill

Abstract

To limit the risk of intrusion of injection fluid into a rear part of a shank and the inside of a hammer drill which receives a striking piston of the hammer drill.SOLUTION: A hydraulic rotary impact hammer drill comprises a fluid injector including a fluid supply inlet and an annular inner groove fluidly connected to the fluid supply inlet, a shank including a fluid injection conduit fluidly connected to an annular inner groove, front and rear main seal gaskets axially disposed on either side of the annular inner groove and configured to cooperate with a first shank portion of the shank, a rear backup seal gasket positioned after the rear main seal gasket and configured to cooperate with a second shank portion of the shank, a leakage passage defined between the shank and the fluid injector, pressure drop generating means configured to generate a pressure drop across a leak passage when the leak flow flows through the leak passage.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] More specifically, the present invention relates to a hydraulic rotary impact hammer drill used in a drill rig.

Background Art

[0002] A drill rig includes, in a known manner, a hydraulic rotary impact hammer drill that is slidably attached to a slide and drives one or more drill bars. The last one of these drill bars carries a tool called a cutter that contacts the rock. Generally, such a hammer drill is intended to drill substantially deep holes, mainly to enable an explosive load to be placed therein. Thus, the hammer drill is a main element of the drill rig. On the one hand, it provides rotation and impact to the cutter via the drill bar to penetrate the rock, and on the other hand, it supplies an injection fluid to remove debris from the drilled hole.

[0003] More specifically, the hammer drill includes a fluid injection portion including a longitudinal passage, a fluid supply inlet intended to be fluidly connected to an injection fluid source, and an annular inner groove fluidly connected to the fluid supply inlet and opening into the longitudinal passage, and a shank intended to be coupled to the drill bar. The shank has a longitudinal axis and extends into the longitudinal passage of the fluid injection portion. The annular inner groove of the fluid injection portion extends around the shank. The shank includes a fluid injection conduit opening at the front end of the shank and a communication orifice configured to fluidly connect the annular inner groove and the fluid injection conduit.

[0004] Thus, the injection fluid flows through the shank, drill bar, and cutter, discharging debris of the material being drilled from the hole during drilling.

[0005] In some applications, especially in mines and underground quarries, water forms this injection fluid, which makes it possible to avoid the spread of rock dust into the atmosphere when it comes out of the hole during drilling.

[0006] All of the injected fluid used must be used to expel the debris. For this purpose, front and rear main seal gaskets, commonly known as "U" seal gaskets, are positioned on either side of the annular groove in the fluid injection section to contain the injected fluid in the injection chamber, which is defined by the annular groove and shank.

[0007] Given the rotational speed of the shank, the injection fluid pressure, the (sometimes approximate) surface conditions of the shank, and the possible axial offset of the shank resulting from the wear of the guide elements provided on the hammer drill, the front and rear main seal gaskets may wear down, causing the injection fluid to bleed from the injection chamber, particularly towards the pressurized and hydraulic areas of the hammer drill.

[0008] However, the presence of incompressible and non-lubricating injected fluid in the aforementioned pressurized and hydraulic areas of a hammer drill quickly leads to irreversible consequences, meaning hammer drill seizure, production losses, and very high repair costs. In fact, when non-lubricating fluid enters the pressurized area of ​​a hammer drill, this fluid may enter the hammer drill's rotating bearings in particular, causing the hammer drill to jam. Depending on its nature, the injected fluid can corrode the inside of the hammer drill in the hydraulic area, and possibly the bearing surface of the hydraulic gasket, which can cause some hydraulic leaks and require the replacement of damaged parts other than the gasket considered. Finally, if the incompressible fluid is present in front of the striking piston and the receiving surface of the shank, and thus at the boundary of the pressurized and hydraulic areas, the pressure of this injected fluid increases considerably, and given the very small clearance provided for the hammer drill, this can cause the hammer drill's sealing gaskets to shift from their receiving housings, thus immediately blocking the hammer drill. However, such blockage of a hammer drill results in significant repair costs.

[0009] To prevent the injection fluid from entering the interior of the hammer drill, it is known that a so-called backup additional seal gasket is placed after the rear main seal gasket, in the injection section and between the rear main seal gasket and the rear backup seal gasket, for a fluid discharge orifice that extends substantially radially and opens to a leak passage defined by the functional clearance between the shank and the injection section. Such a fluid discharge orifice allows the injection fluid flowing through the leak passage to exit the hammer drill due to leakage of the rear main seal gasket. Furthermore, it is expected that the discharge of the injection fluid through this fluid discharge orifice will attract the operator's attention, prompting them to stop the hammer drill and replace the defective seal gasket.

[0010] Following the rear backup seal gasket is the aforementioned pressurized area, which is generally swept by a compressible fluid flow that is lubricated to limit wear and corrosion. The pressure of this compressible fluid restricts the injection fluid from entering the pressurized area.

[0011] However, if the rear main seal gasket leaks and the injected fluid is at high pressure, the leak is realized by a wire-shaped or tubular jet around the shank, either across the angular portion of the shank or around its entire circumference. The jet generated in this way has a very high velocity and therefore a very high dynamic pressure. This injected fluid jet can lift the rear backup seal gasket and flow between the rear backup seal gasket and the shank, thus entering a pressurized area where the static pressure is well below the dynamic pressure of the injected fluid. The hammer drill is then filled with incompressible fluid and damaged very rapidly. This phenomenon can occur at a static pressure measured in the leak passage, although it is lower than the pressurized pressure. [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention aims to overcome these drawbacks.

[0013] Therefore, the technical problem at the origin of the present invention is to provide a hydraulic rotary impact hammer drill with a simple and economical structure, while limiting the risk of injection fluid entering the rear of the shank and the inside of the hammer drill that receives the impact piston. [Means for solving the problem]

[0014] For this purpose, the present invention provides a hammer drill body, a fluid injection section provided at the front of the hammer drill body, a shank intended to be coupled to at least one drill bar equipped with a tool, a striking piston slidably mounted inside the hammer drill body along the striking axis and configured to strike the shank, annular front main seal gasket and rear main seal gasket extending around the shank, respectively, annular rear backup seal gasket extending around the shank, a leak passage defined between the shank and the fluid injection section and extending from the rear main seal gasket to the rear backup seal gasket, and at least one fluid discharge orifice provided in the fluid injection section and fluidically connected to the leak passage, wherein the fluid injection section includes a longitudinal passage, a fluid supply inlet intended to be fluidically connected to an injection fluid source, and an annular internal groove fluidly connected to the fluid supply inlet and opening to the longitudinal passage, the shank having a longitudinal axis and extending to the longitudinal passage of the fluid injection section The present invention relates to a hydraulic rotary impact hammer drill, wherein the annular groove extends around the shank, the shank includes a fluid injection conduit extending over at least a portion of the length of the shank, and a communication orifice configured to fluidly connect the annular groove and the fluid injection conduit, the front and rear main seal gaskets are fixed to the fluid injection section and axially positioned on either side of the annular groove, the front and rear main seal gaskets are configured to cooperate tightly with a first shank portion of the shank, the rear backup seal gasket is positioned behind the rear main seal gasket and fixed to the fluid injection section, the rear backup seal gasket is configured to cooperate tightly with a second shank portion of the shank, and in the event of leakage of the injected fluid into the rear main seal gasket, the leakage flow is intended to flow into the leakage passage, and the at least one fluid discharge orifice is configured to discharge the leakage flow flowing into the leakage passage to the outside of the hydraulic rotary impact hammer drill.

[0015] The first shank portion is substantially cylindrical and has a first outer diameter, the second shank portion is substantially cylindrical and has a second outer diameter that is strictly larger than the first outer diameter, and the hydraulic rotary impact hammer drill is equipped with a pressure drop generating means disposed in the leakage passage and configured to generate a pressure drop in the leakage passage when the leakage flow flows into the leakage passage, the pressure drop generating means includes a deflection surface (surface de deviation) provided on the shank and disposed between the first shank portion and the second shank portion (for example, disposed in the axial direction), the deflection surface is configured to deviate the leakage flow that flows into the leakage passage toward the rear backup seal gasket in a flow direction that transverses the longitudinal axis of the shank (i.e., intersects the longitudinal axis of the shank).

[0016] The presence of such pressure drop generating means within the leakage passage makes it possible to substantially reduce the flow velocity of the leakage flow from the rear main seal gasket to the rear backup seal gasket in the case of leakage of the rear main seal gasket, and thus substantially reduce the dynamic pressure acting on the rear backup seal gasket.

[0017] Therefore, the specific configuration of the hammer drill according to the present invention provides an extended service life for the rear backup seal gasket, reducing the frequency of replacement of the rear backup seal gasket.

[0018] Furthermore, if the dynamic pressure acting on the rear backup seal gasket is reduced by any potential leakage flow originating from the rear main seal gasket, the dominant pressurizing pressure behind the rear backup seal gasket should be sufficient to resist the intrusion of any potential injection fluid into the pressurized portion of the hammer drill.

[0019] As a result, the specific configuration of the hammer drill according to the present invention makes it possible to improve the reliability and safety of using the hammer drill.

[0020] Furthermore, the hydraulic rotary impact hammer drill may have one or more of the following features, considered individually or in combination.

[0021] According to one embodiment of the present invention, the pressure drop generating means is configured such that the leakage passage has a passage cross-section that varies between the rear main seal gasket and the rear backup seal gasket.

[0022] According to one embodiment of the present invention, the deflecting surface is configured to deflect the leakage flow from a flow direction substantially parallel to the longitudinal axis of the shank to a flow direction that crosses, i.e., intersects, the longitudinal axis of the shank.

[0023] According to one embodiment of the present invention, the deflecting surface is configured to deflect the leakage flow flowing into the leakage passage toward the rear backup seal gasket so that the leakage flow deviates from, i.e., escapes from, the longitudinal axis of the shank. In other words, the deflecting surface extends toward the rear backup seal gasket while deviating from the longitudinal axis of the shank.

[0024] According to one embodiment of the present invention, the deflecting surface is annular.

[0025] According to one embodiment of the present invention, the deflecting surface extends transversely to, i.e., intersects, the longitudinal axis of the shank and extends along an extension direction that crosses the longitudinal axis of the shank.

[0026] According to one embodiment of the present invention, the deflecting surface is inclined at an inclination angle included between 1° and 89°, for example, between 30° and 60°, with respect to the longitudinal axis of the shank.

[0027] According to one embodiment of the present invention, the deflecting surface has a substantially frustoconical shape.

[0028] According to another embodiment of the present invention, the deflection surface extends substantially perpendicular to the longitudinal axis of the shank.

[0029] According to another embodiment of the present invention, the deflection surface diverges in the direction of the rear backup seal gasket.

[0030] According to another embodiment of the present invention, the deflection surface diverges in the direction of the rear main seal gasket.

[0031] According to another embodiment of the present invention, the deflection surface is at least partially formed by a concave portion having a curve and a radius of curvature.

[0032] According to one embodiment of the present invention, the shank has a deflection collar provided on an outer surface of the shank and including the deflection surface.

[0033] According to one embodiment of the present invention, the shank includes an annular groove provided on an outer surface of the shank and disposed (e.g., axially) between the first shank portion and the deflection surface, and a minimum diameter of the annular groove is smaller than the first outer diameter of the first shank portion.

[0034] According to one embodiment of the present invention, the leakage passage includes a discharge chamber that at least partially extends around the shank and is disposed (e.g., axially) between the rear main seal gasket and the rear backup seal gasket, and the at least one fluid discharge orifice opens into the discharge chamber.

[0035] According to one embodiment of the present invention, the discharge chamber is annular.

[0036] According to one embodiment of the present invention, the fluid injection portion includes an annular discharge groove that opens into the longitudinal passage and partially defines the discharge chamber.

[0037] According to one embodiment of the present invention, the deflection surface is configured to redirect the leakage flow that flows into the leakage passage in the direction of the rear backup seal gasket toward the bottom wall of the annular discharge groove.

[0038] According to one embodiment of the present invention, the shank includes a connecting portion axially positioned between the first and second shank portions, the connecting portion including an outer peripheral surface having a surface roughness configured to generate a pressure drop in the leakage passage when the leakage flow flows into the leakage passage, and the pressure drop generating means is at least partially formed by the surface roughness of the outer peripheral surface.

[0039] According to one embodiment of the present invention, the outer circumferential surface of the connecting portion has a surface roughness higher than the surface roughness of the outer circumferential surfaces of the first and second shank portions.

[0040] According to one embodiment of the present invention, the fluid injection portion includes a rear intermediate portion disposed axially between the rear main seal gasket and the rear backup seal gasket, the rear intermediate portion including an inner circumferential surface having a surface roughness configured to generate a pressure drop in the leakage passage when the leakage flow flows into the leakage passage, the pressure drop generating means being at least partially formed by the surface roughness of the inner circumferential surface.

[0041] According to one embodiment of the present invention, the inner circumferential surface has a higher surface roughness than the other inner circumferential surfaces of the fluid injection portion.

[0042] According to one embodiment of the present invention, the hydraulic rotary impact hammer drill further comprises a rotary drive device configured to rotate the shank around a rotation axis substantially coinciding with the impact axis.

[0043] According to one embodiment of the present invention, the hydraulic rotary impact hammer drill further comprises: an annular front backup seal gasket extending around the shank; an additional leak passage defined between the shank and the fluid injection section and extending from the front main seal gasket to the front backup seal gasket; at least one additional fluid discharge orifice provided in the fluid injection section and fluidically connected to the additional leak passage; and an additional pressure drop generating means disposed in the additional leak passage and configured to generate a pressure drop in the additional leak passage when the leak flow flows into the additional leak passage, wherein the front backup seal gasket is positioned in front of the front main seal gasket and fixed to the fluid injection section; the front backup seal gasket is configured to cooperate tightly with a third shank section of the shank and is intended to allow the leak flow to flow into the additional leak passage when the injected fluid leaks into the front main seal gasket; and the at least one additional fluid discharge orifice is configured to discharge the leak flow flowing into the additional leak passage to the outside of the hydraulic rotary impact hammer drill.

[0044] According to one embodiment of the present invention, the third shank portion is substantially cylindrical and has a third outer diameter that is strictly smaller than the first outer diameter.

[0045] According to one embodiment of the present invention, the fluid injection section has a first part and a second part, each including a substantially cylindrical first inner surface and a second inner surface, and the front and rear main seal gaskets are fixed to two annular fixing grooves provided on the first and second inner surfaces, respectively.

[0046] According to one embodiment of the present invention, the fluid injection portion has a rear portion including a substantially cylindrical rear inner surface, and the rear backup seal gasket is fixed in an annular fixing groove provided on the rear inner surface. The rear portion is positioned behind the first and second portions.

[0047] According to one embodiment of the present invention, the fluid injection section has a front section including a substantially cylindrical front inner surface, and the front backup seal gasket is fixed to an annular fixing groove provided on the front inner surface. The front section is positioned in front of the first and second sections.

[0048] According to one embodiment of the present invention, the additional pressure drop generating means includes an additional deflection surface provided in the fluid injection section and positioned between the first shank portion and the third shank portion (for example, positioned in the axial direction), wherein the additional deflection surface is configured to redirect the leakage flow flowing into the additional leakage passage toward the front backup seal gasket in a flow direction that transverses the longitudinal axis of the shank (i.e., intersects the longitudinal axis of the shank).

[0049] According to one embodiment of the present invention, the additional deflection surface is configured to redirect the leakage flow from a flow direction substantially parallel to the longitudinal axis of the shank to a flow direction that transverses the longitudinal axis of the shank, i.e., intersects the longitudinal axis of the shank.

[0050] According to one embodiment of the present invention, the additional deflection surface is configured to redirect the leakage flow toward the longitudinal axis of the shank.

[0051] According to one embodiment of the present invention, the front inner surface has an inner diameter smaller than the inner diameter of the first inner surface.

[0052] According to one embodiment of the present invention, the additional deflection surface is annular and connects the front inner surface to the first inner surface.

[0053] According to one embodiment of the present invention, the additional deflection surface is inclined with respect to the longitudinal axis of the shank according to an inclination angle that includes between 1° and 89°, for example, between 30° and 60°.

[0054] According to one embodiment of the present invention, the additional deflection surface converges in the direction of the front main seal gasket.

[0055] According to one embodiment of the present invention, the additional deflection surface converges in the direction of the front backup seal gasket.

[0056] According to one embodiment of the present invention, the additional leakage passage includes an additional discharge chamber that extends at least partially around the shank and is positioned between the front main seal gasket and the front backup seal gasket (for example, positioned axially), wherein the at least one additional discharge orifice opens into the additional discharge chamber.

[0057] The present invention will be better understood from the following description, with reference to the accompanying drawings, in which the same reference numerals correspond to structurally and / or functionally identical or similar elements. [Brief explanation of the drawing]

[0058] [Figure 1] Figure 1 is a schematic longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to the first embodiment of the present invention. [Figure 2] Figure 2 is a partial longitudinal cross-sectional view of the hydraulic rotary impact hammer drill shown in Figure 1. [Figure 3] Figure 3 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to a second embodiment of the present invention. [Figure 4] Figure 4 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to a third embodiment of the present invention. [Figure 5] Figure 5 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to the fourth embodiment of the present invention. [Figure 6] Figure 6 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to a fifth embodiment of the present invention. [Figure 7] Figure 7 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to the sixth embodiment of the present invention. [Figure 8]Figure 8 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to the seventh embodiment of the present invention. [Figure 9] Figure 9 is a partial longitudinal cross-sectional view of a hydraulic rotary impact hammer drill according to the eighth embodiment of the present invention. [Modes for carrying out the invention]

[0059] Figures 1 and 2 show a first embodiment of a hydraulic rotary impact hammer drill 2 intended for drilling mine holes. More specifically, the hydraulic rotary impact hammer drill 2 includes a hammer drill body 3, which is configured to be slidably mounted on a slide (not shown in the figures) provided on a carrier machine.

[0060] The hydraulic rotary impact hammer drill 2 comprises an impact system 4 including impact pistons 5 mounted to slide alternately within a piston cylinder 6 defined by the hammer drill body 3 along the impact axis A. The impact pistons 5 and piston cylinder 6 divide an annular first control chamber 7 and a second control chamber 8 having a larger cross-section than the first control chamber 7 and opposing the first control chamber 7.

[0061] The striking system 4 further comprises a control distributor 9 positioned to control the alternating movement of the striking piston 5 inside the piston cylinder 6 according to the alternating striking stroke and return stroke. The control distributor 9 is configured to set up a second control chamber 8 by alternately connecting to a high-pressure fluid supply conduit 11, such as a high-pressure incompressible fluid supply conduit, during the striking stroke of the striking piston 5, and to a low-pressure fluid return conduit 12, such as a low-pressure incompressible fluid return conduit, during the return stroke of the striking piston 5. Advantageously, the first control chamber 7 is permanently supplied with high-pressure fluid through a supply channel 13 connected to the high-pressure fluid supply conduit 11.

[0062] The high-pressure supply conduit 11 and the low-pressure fluid return conduit 12 belong to the main hydraulic supply circuit, which is equipped with the impact system 4.

[0063] The hydraulic rotary impact hammer drill 2 further comprises a shank 14 intended to be coupled in a known manner to at least one drill bar (not shown in the figure) equipped with a tool also called a cutter. The shank 14 extends longitudinally along a longitudinal axis advantageously coinciding with the striking axis A and has a first end 15 having an end face 15.1 oriented toward the striking piston 5 and intended to strike the striking piston 5 during each operating cycle of the hydraulic rotary impact hammer drill 2, and a second end 16 opposite to the first end 15 and intended to be coupled to at least one drill bar.

[0064] The shank 14 includes a fluid injection conduit 17 that extends longitudinally and opens to the end face 16.1 of the second end 16. Furthermore, the shank 14 includes a communication orifice 18 that opens radially to the fluid injection conduit 17 and to the outer surface of the shank 14, respectively.

[0065] The hydraulic rotary impact hammer drill 2 further includes a fluid injection unit 19 provided at the front of the hammer drill body 3. For example, the fluid injection unit 19 may be detachably attached to the front of the hammer drill body 3.

[0066] According to the embodiments shown in Figures 1 and 2, the fluid injection section 19 includes an injection body 21 which is substantially tubular and arranged around the shank 14. Therefore, the injection body 21 includes a longitudinal passage 22 through which the shank 14 extends.

[0067] The injection body 21 further includes a fluid supply inlet 23 that is fluidically connected to a fluid transfer conduit 24 connected to an injection fluid source, and an annular inner groove 25 that extends around the shank 14 and to the bottom where the fluid supply inlet 23 opens. A communication orifice 18 provided in the shank 14 opens into the annular inner groove 25 so that the fluid injection conduit 17 is fluidly connected to the fluid transfer conduit 24 via the annular inner groove 25 and the fluid supply inlet 23. For example, the injection fluid transferred by the fluid transfer conduit 24 may consist of water or air.

[0068] Furthermore, the hydraulic rotary impact hammer drill 2 includes an annular front main seal gasket 26 and a rear main seal gasket 27, respectively, which extend around the shank 14. The front and rear main seal gaskets 26, 27 are axially positioned on either side of the annular inner groove 25 and are configured to cooperate tightly with the first shank portion 14.1 of the shank 14. For example, each of the front and rear main seal gaskets 26, 27 may have a substantially U-shaped cross-section and may include an annular seal lip configured to cooperate tightly with the first shank portion 14.1.

[0069] According to the embodiments shown in Figures 1 and 2, the injection body 21 has a first part 21.1 and a second part 21.2, which include a first inner surface and a second inner surface that are substantially cylindrical in shape, and the front and rear main seal gaskets 26 and 27 are fixed to two annular fixing grooves provided on the first and second inner surfaces, respectively.

[0070] The hydraulic rotary impact hammer drill 2 also includes a rear backup seal gasket 28 that is annular and extends around the shank 14. The rear backup seal gasket 28 is positioned after the rear main seal gasket 27 and is configured to cooperate tightly with the second shank portion 14.2 of the shank 14.

[0071] According to the embodiments shown in Figures 1 and 2, the injection body 21 has a rear portion 21.3 including a substantially cylindrical rear inner surface, and the rear backup seal gasket 28 is fixed in an annular fixing groove provided on the rear inner surface.

[0072] According to the embodiments shown in Figures 1 and 2, the first shank portion 14.1 is substantially cylindrical and has a first outer diameter, and the second shank portion 14.2 is substantially cylindrical and has a second outer diameter that is strictly larger than the first outer diameter. Furthermore, the rear inner surface has an inner diameter that is larger than the inner diameter of the first inner surface.

[0073] Furthermore, the hydraulic rotary impact hammer drill 2 includes a leak passage 29 defined between the shank 14 and the injector 21 and extending from the rear main seal gasket 27 to the rear backup seal gasket 28. If the injector fluid leaks into the rear main seal gasket 27, the leak is intended to flow into the leak passage 29.

[0074] According to the embodiments shown in Figures 1 and 2, the leakage passage 29 has a passage cross-section that changes between the rear main seal gasket 27 and the rear backup seal gasket 28, and in particular includes an annular discharge chamber 31 that extends around the shank 14. The discharge chamber 31 is axially positioned between the rear main seal gasket 27 and the rear backup seal gasket 28. Advantageously, the injector 21 includes an annular discharge groove 32 that opens to the longitudinal passage 22 and partially partitions the discharge chamber 31. The leakage passage 29 further includes an upstream passage portion defined by a functional clearance between the first shank portion 14.1 and the second inner surface, and a downstream passage portion defined by a functional clearance between the second shank portion 14.2 and the rear inner surface.

[0075] Furthermore, the hydraulic rotary impact hammer drill 2 also includes one or more fluid discharge orifices 33 provided in the injection body 21 and opening, for example, radially to the discharge chamber 31. Each fluid discharge orifice 33 is configured to discharge the leakage flow that flows through the leakage passage 29 to the outside of the hydraulic rotary impact hammer drill 2.

[0076] The hydraulic rotary impact hammer drill 2 further includes a pressure drop generating means positioned in the leakage passage 29 and configured to generate a pressure drop in the leakage passage 29 when leakage flow flows into the leakage passage 29.

[0077] According to the embodiments shown in Figures 1 and 2, the pressure drop generating means includes an annular deflection surface 34 provided on the shank 14. The deflection surface 34 connects the first shank portion 14.1 and the second shank portion 14.2.

[0078] According to the embodiments shown in Figures 1 and 2, the deflection surface 34 has a substantially frustoconical shape and diverges in the direction of the rear backup seal gasket 28. The deflection surface 34 is inclined according to an inclination angle configured between 1° and 89°, for example between 30° and 60°, and advantageously about 45° with respect to the longitudinal axis of the shank 14. Nevertheless, according to one embodiment of the present invention, the deflection surface 34 may extend substantially perpendicular to the longitudinal axis of the shank 14. Such a configuration of the deflection surface 34 allows for a further increase in the pressure drop that occurs in the leakage passage 29.

[0079] More specifically, the deflection surface 34 is configured to redirect the leakage flow that flows into the leakage passage 29 toward the rear backup seal gasket 28 from a flow direction substantially parallel to the longitudinal axis of the shank 14 to a flow direction transverse to the longitudinal axis of the shank 14, i.e., a flow direction intersecting the longitudinal axis of the shank 14.

[0080] According to the embodiment shown in Figure 2, the deflection surface 34 is configured to redirect the leakage flow that flows into the leakage passage 29 in the direction of the rear backup seal gasket 28 toward the bottom wall of the annular discharge groove 32, and thus such that the leakage flow deviates from the longitudinal axis of the shank 14.

[0081] Therefore, if the rear main seal gasket 27 is leaking and the injected fluid is high-pressure water, the water jet originating from the rear main seal gasket 27 will be deflected at least once by the deflection surface 34 provided on the shank 14 and twice by the bottom wall of the annular discharge groove 32 before loading the rear backup seal gasket 28. These pressure drops, in addition to the enlargement of the cross-section of the leakage passage 29 in the discharge chamber 31, will significantly limit the flow velocity of the water jet and thus reduce the dynamic pressure acting on the rear backup seal gasket 28. Thus, the dominant pressurized pressure behind the rear backup seal gasket 28 will be sufficient to resist the potential intrusion of the injected fluid into the pressurized portion of the hydraulic rotary impact hammer drill 2.

[0082] The hydraulic rotary impact hammer drill 2 also includes a rotary drive system 35 configured to rotate the shank 14 around a rotation axis substantially coinciding with the impact axis A. For example, the rotary drive system 35 includes a coupling member 36, such as a coupling pinion, which is tubular and positioned around the shank 14. The coupling member 36 includes a male coupling spline and a female coupling spline, which are rotationally coupled to female and male coupling splines provided on the shank 14, respectively.

[0083] Advantageously, the coupling member 36 includes outer teeth that are rotatably coupled to the output shaft of a drive motor 37, such as a hydraulic motor, which is hydraulically driven by an external hydraulic power supply circuit belonging to the rotary drive system 35. For example, the rotary drive system 35 may include an intermediate pinion 38 coupled on the output shaft of the drive motor 37 on the one hand and to the outer teeth of the coupling member 36 on the other.

[0084] When the hydraulic rotary impact hammer drill 2 is in operation, the shank 14 is rotated thanks to the drive motor 37, and the shank 14 receives cyclic impacts of the impact piston 5, which are secured by the impact system 4 supplied by the main hydraulic supply circuit, at its end face 15.1.

[0085] Figure 3 shows a hydraulic rotary impact hammer drill 2 according to a second embodiment of the present invention, which is essentially different from the first embodiment in that the injection body 21 does not have an annular discharge groove 32.

[0086] Figure 4 shows a hydraulic rotary impact hammer drill 2 according to a third embodiment of the present invention, which is essentially different from the first embodiment in that the deflection surface 34 is configured to guide the leakage flow that flows into the leakage passage 29 in the direction of the rear backup seal gasket 28 toward the rear main seal gasket 27. Such configuration of the deflection surface 34 makes it possible to further increase the pressure drop that occurs in the leakage passage 29. According to such an embodiment of the present invention, the deflection surface 34 diverges in the direction of the rear main seal gasket 27. According to such an embodiment of the present invention, the deflection surface 34 is inclined according to an inclination angle configured between 91° and 179°, for example between 120° and 150°, and preferably about 135°, with respect to the longitudinal axis of the shank 14.

[0087] Figure 5 shows a hydraulic rotary impact hammer drill 2 according to the fourth embodiment of the present invention, which is essentially different from the second embodiment in that the deflection surface 34 is at least partially formed by a curved concave portion having a radius of curvature.

[0088] Figure 6 shows a hydraulic rotary impact hammer drill 2 according to a fifth embodiment of the present invention, which differs in essence from the third embodiment in that the shank 14 includes an annular groove 39 provided on the outer surface of the shank 14 and positioned axially between the first shank portion 14.1 and the deflection surface 34. Advantageously, the minimum diameter of the annular groove 39 is smaller than the first outer diameter of the first shank portion 14.1. Such a configuration of the shank 14 allows for a further increase in the pressure drop generated within the leakage passage 29.

[0089] Figure 7 shows a hydraulic rotary impact hammer drill 2 according to the sixth embodiment of the present invention, which differs from the first embodiment in that the shank 14 has a deflection collar 41 provided on the outer surface of the shank 14 and including a deflection surface 34.

[0090] Figure 8 shows a hydraulic rotary impact hammer drill 2 according to a seventh embodiment of the present invention, which is essentially different from the first embodiment in that the hydraulic rotary impact hammer drill 2 further comprises an annular front backup seal gasket 44 extending around the shank 14, the front backup seal gasket 44 being positioned in front of the front main seal gasket 26 and configured to cooperate tightly with the third shank portion 14.3 of the shank 14.

[0091] According to the embodiment shown in Figure 8, the injection body 21 is substantially cylindrical and has a front portion 21.4 including a front inner surface, and the front backup seal gasket 44 is fixed in an annular fixing groove provided on the front inner surface.

[0092] According to the embodiment shown in Figure 8, the third shank portion 14.3 is substantially cylindrical and has a third outer diameter substantially the same as the first outer diameter of the first shank portion 14.1, and the front inner surface has an inner diameter substantially the same as the inner diameter of the first inner surface.

[0093] The hydraulic rotary impact hammer drill 2 further comprises an additional leak passage 45 defined between the shank 14 and the injector 21 and extending from the front main seal gasket 26 to the front backup seal gasket 44. The leak flow is intended to flow into the additional leak passage 45 if the injector fluid leaks into the front main seal gasket 26.

[0094] According to the embodiment shown in Figure 8, the additional leakage passage 45 has a passage cross-section that changes between the front main seal gasket 26 and the front backup seal gasket 44, and in particular includes an additional discharge chamber 46 that is annular and extends around the shank 14. The additional discharge chamber 46 is axially positioned between the front main seal gasket 26 and the front backup seal gasket 44. Advantageously, the injector 21 includes an additional annular discharge groove 47 that opens to the longitudinal passage 22 and partially partitions the additional discharge chamber 46.

[0095] The hydraulic rotary impact hammer drill 2 also includes one or more additional fluid discharge orifices 48 provided in the injection body 21 and opening, for example, radially to an additional discharge chamber 46. Each additional fluid discharge orifice 48 is configured to discharge the leakage flow that flows through the additional leakage passage 45 to the outside of the hydraulic rotary impact hammer drill 2.

[0096] According to the embodiment shown in Figure 8, the injector 21 includes a pressurizing channel 49 that extends over at least a portion of the length of the body and opens substantially radially to the front inner surface. Such a pressurizing channel 49 is supplied with a pressurized fluid that is generally compressible and ideally lubricated, which allows for limiting rotational and translational friction between the shank 14 and the injector 21.

[0097] Figure 9 shows a hydraulic rotary impact hammer drill 2 according to the eighth embodiment of the present invention, which is essentially different from the seventh embodiment in that the third outer diameter of the third shank portion 14.3 is strictly smaller than the first outer diameter of the first shank portion 14.1, the front inner surface has an inner diameter smaller than the inner diameter of the first inner surface, and the hydraulic rotary impact hammer drill 2 is equipped with an additional pressure drop generating means that is located in the additional leakage passage 45 and is configured to generate a pressure drop in the additional leakage passage 45 when leakage flow flows into the additional leakage passage 45.

[0098] According to the embodiment shown in Figure 9, the pressure drop generating means includes an annular additional deflection surface 51 provided on the injection body 21. The additional deflection surface 51 connects its front inner surface to the first inner surface.

[0099] According to the embodiment shown in Figure 9, the additional deflection surface 51 extends substantially perpendicular to the longitudinal axis of the shank 14 and is configured to redirect the leakage flow that flows into the additional leakage passage 45 toward the front backup seal gasket 44 from a flow direction substantially parallel to the longitudinal axis of the shank 14 to a flow direction perpendicular to the longitudinal axis of the shank 14. Advantageously, the additional deflection surface 51 is configured to redirect the leakage flow toward the longitudinal axis of the shank 14.

[0100] According to a modified version of the present invention, the additional deflection surface 51 may have a substantially frustoconical shape and may converge in the direction of the front backup seal gasket 44. For example, the additional deflection surface 51 may be inclined according to an inclination angle that is configured between 1° and 89°, for example between 30° and 60°, and preferably about 45°, with respect to the longitudinal axis of the shank 14.

[0101] Therefore, if the front main seal gasket 26 is leaking and the injected fluid is high-pressure water, the water jet originating from the front main seal gasket 26 will be deflected at least once by the additional deflection surface 51 provided on the injector 21 and twice by the outer surface of the third shank portion 14.3 before loading the front backup seal gasket 44. These pressure drops will significantly limit the flow velocity of the water jet and thus reduce the dynamic pressure acting on the front backup seal gasket 44. Thus, leakage of the injected fluid through the front main seal gasket 26 can be discharged through the additional fluid discharge orifice 48 without directly loading the front backup seal gasket 44, significantly extending its service life.

[0102] Furthermore, assuming that the dynamic pressure acted upon by the injected fluid at the front backup seal gasket 44 is significantly reduced, the dominant pressurizing pressure in front of the front backup seal gasket 44 will be sufficient to limit the risk of leakage fluid entering the pressurizing channel in the pressurizing area or hydraulic area of ​​the hydraulic rotary impact hammer drill due to the presence of the pressurizing channel 49. Thus, the presence of the additional deflection surface 51 makes it possible to further enhance the reliability of the hydraulic rotary impact hammer drill 2 according to the present invention.

[0103] According to another modification of the present invention, the additional deflection surface 51 may converge in the direction of the front main seal gasket 26 and may be configured to guide the leakage flow that flows into the additional leakage passage 45 in the direction of the front backup seal gasket 44 toward the front main seal gasket 26. According to such embodiments of the present invention, the additional deflection surface 51 is inclined according to an inclination angle that is configured between 91° and 179°, for example between 120° and 150°, and preferably about 135° with respect to the longitudinal axis of the shank 14.

[0104] In a modified version of the present invention, the injector 21 may include a rear intermediate portion which would be axially positioned between the rear main seal gasket 27 and the rear backup seal gasket 28, the rear intermediate portion which would include an inner circumferential surface having a surface roughness configured to generate a pressure drop in the leakage passage 29 (in addition to the pressure drop generated by the deflection surface 34) when the leakage flow flows into the leakage passage 29. In such a modified version of the present invention, the pressure drop generating means would be formed by the deflection surface 34 and the surface roughness of the inner circumferential surface.

[0105] According to another embodiment of the present invention, the shank 14 may include, in addition to the deflection surface 34, a connecting portion axially positioned between the first and second shank portions, the connecting portion including an outer surface having a surface roughness configured to generate a pressure drop in the leakage passage (in addition to the pressure drop generated by the deflection surface 34) when a leakage flow flows into the leakage passage. According to such a modification of the present invention, the pressure drop generating means would be formed by the deflection surface 34 and the surface roughness of the outer surface.

[0106] Needless to say, the present invention is not limited to the sole embodiment of the hydraulic rotary impact hammer drill described above as an example, but rather encompasses all variations thereof.

Claims

1. A hammer drill body (3), A fluid injection section (19) provided at the front of the hammer drill body (3); a shank (14) intended to be coupled to at least one drill burr equipped with a tool; a striking piston (5) slidably mounted inside the hammer drill body (3) along a striking axis (A) and configured to abut against the shank (14); a front main seal gasket (26) and a rear main seal gasket (27) each of which is annular and extends around the shank (14); a rear backup seal gasket (28) that is annular and extends around the shank (14); a leakage passage (29) defined between the shank (14) and the fluid injection portion (19) and extending from the rear main seal gasket (27) to the rear backup seal gasket (28); at least one fluid discharge orifice (33) provided in the fluid injection portion (19) and fluidly connected to the leakage passage (29); Equipped with The fluid injection section (19) comprises a longitudinal passage (22), a fluid supply inlet (23) intended to be fluidly connected to a source of injection fluid, and an annular internal groove (25) fluidly connected to the fluid supply inlet and opening into the longitudinal passage (22), the shank (14) has a longitudinal axis and extends through the longitudinal passage (22) of the fluid injection portion (19), the annular internal groove (25) extends around the shank (14), the shank (14) includes a fluid injection conduit (17) extending over at least a portion of the length of the shank (14) and a communication orifice (18) configured to fluidly connect the annular internal groove (25) and the fluid injection conduit (17); the front and rear main seal gaskets (26, 27) are fixed to the fluid injection portion (19) and are axially disposed on either side of the annular internal groove (25), the front and rear main seal gaskets (26, 27) being configured to tightly cooperate with a first shank portion (14.1) of the shank (14); the rear backup seal gasket (28) is disposed behind the rear main seal gasket (27) and fixed to the fluid injection portion (19), the rear backup seal gasket (28) being configured to tightly cooperate with a second shank portion (14.2) of the shank (14); In the event that injection fluid leaks into the rear main seal gasket (27), leakage flow is intended to flow into the leakage passage (29); The at least one fluid discharge orifice (33) is configured to discharge the leakage flow through the leakage passage (29) to the outside of the hydraulic rotary impact hammer drill (2). A hydraulic rotary impact hammer drill (2), 1. The hydraulic rotary impact hammer drill (2), characterized in that the first shank portion (14.1) is generally cylindrical and has a first outer diameter, and the second shank portion (14.2) is generally cylindrical and has a second outer diameter strictly greater than the first outer diameter, the hydraulic rotary impact hammer drill (2) comprising pressure drop generating means disposed in the leakage passage (29) and configured to generate a pressure drop in the leakage passage (29) when the leakage flow flows into the leakage passage (29), the pressure drop generating means including a deflection surface (34) provided on the shank (14) and disposed between the first shank portion (14.1) and the second shank portion (14.2), the deflection surface (34) configured to redirect the leakage flow in the leakage passage (29) towards the rear backup seal gasket (28) in a flow direction transverse to the longitudinal axis of the shank (14).

2. 2. The hydraulic rotary impact hammer drill (2) according to claim 1, wherein the pressure drop generating means is configured such that the leakage passage (29) has a passage cross-section that varies between the rear main seal gasket (27) and the rear backup seal gasket (28).

3. 2. The hydraulic rotary impact hammer drill (2) of claim 1, wherein the deflection surface (34) is configured to redirect the leakage flow through the leakage passage (29) toward the rear backup seal gasket (28) so that the leakage flow deviates from the longitudinal axis of the shank (14).

4. 4. A hydraulic rotary impact hammer drill (2) as claimed in any one of claims 1 to 3, wherein the deflection surface (34) is annular.

5. 4. A hydraulic rotary impact hammer drill (2) as claimed in any one of claims 1 to 3, wherein the deflection surface (34) extends transversely to the longitudinal axis of the shank (14).

6. 6. The hydraulic rotary impact hammer drill (2) according to claim 5, wherein the deflection surface (34) is inclined relative to the longitudinal axis of the shank (14) according to an inclination angle comprised between 1° and 89°, for example between 30° and 60°.

7. 4. The hydraulic rotary impact hammer drill (2) of claim 1, wherein the shank (14) has a deflection collar (41) provided on an outer surface of the shank (14) and including the deflection surface (34).

8. 4. The hydraulic rotary impact hammer drill (2) of claim 1, wherein the shank (14) includes an annular groove (39) provided on an outer surface of the shank (14) and disposed between the first shank portion (14.1) and the deflection surface (34), and a minimum diameter of the annular groove (39) is smaller than the first outer diameter of the first shank portion (14.1).

9. 4. The hydraulic rotary impact hammer drill (2) of claim 1, wherein the leakage passage (29) includes a discharge chamber (31) extending at least partially around the shank (14) and disposed between the rear main seal gasket (27) and the rear backup seal gasket (28), and the at least one fluid discharge orifice (33) opens into the discharge chamber (31).

10. 4. The hydraulic rotary impact hammer drill (2) according to claim 1, wherein the shank (14) includes a connection portion arranged axially between the first and second shank portions (14.1, 14.2), the connection portion including an outer circumferential surface having a surface roughness configured to generate a pressure drop in the leakage passage (29) when the leakage flow flows into the leakage passage (29), the pressure drop generating means being at least partially formed by the surface roughness of the outer circumferential surface.

11. 4. The hydraulic rotary impact hammer drill (2) according to claim 1, wherein the fluid injection portion (19) includes a rear intermediate portion axially disposed between the rear main seal gasket (27) and the rear backup seal gasket (28), the rear intermediate portion including an inner circumferential surface having a surface roughness configured to generate a pressure drop in the leakage passage (29) when the leakage flow flows into the leakage passage (29), and the pressure drop generating means is at least partially formed by the surface roughness of the inner circumferential surface.

12. a front backup seal gasket (44) that is annular and extends around the shank (14); an additional leakage passage (45) defined between the shank (14) and the fluid injection portion (19) and extending from the forward main seal gasket (26) to the forward backup seal gasket (44); at least one additional fluid discharge orifice (48) provided in the fluid injection portion (19) and fluidly connected to the additional leakage passage (45); additional pressure drop creating means disposed in the additional leakage passage (45) and configured to create a pressure drop in the additional leakage passage (45) when the leakage flow flows through the additional leakage passage (45); Further equipped with the front backup seal gasket (44) is disposed in front of the front main seal gasket (26) and fixed to the fluid injection portion (19), the front backup seal gasket (44) being configured to tightly cooperate with a third shank portion (14.3) of the shank (14); In the event that the injection fluid leaks into the front main seal gasket (26), the leakage flow is intended to flow into the additional leakage passage (45); 4. The hydraulic rotary impact hammer drill (2) according to any one of claims 1 to 3, wherein the at least one additional fluid discharge orifice (48) is configured to discharge the leakage flow flowing through the additional leakage passage (45) outside the hydraulic rotary impact hammer drill (2).

13. 13. The hydraulic rotary impact hammer drill (2) according to claim 12, wherein the third shank portion (14.3) is generally cylindrical and has a third outer diameter strictly smaller than the first outer diameter.

14. 14. The hydraulic rotary impact hammer drill (2) according to claim 13, wherein the additional pressure drop generating means comprises an additional deflection surface (51) provided on the fluid injection portion (19) and arranged between the first shank portion (14.1) and the third shank portion (14.3), the additional deflection surface (51) being configured to redirect the leakage flow flowing in the additional leakage passage (45) towards the front backup seal gasket (44) in a flow direction transverse to the longitudinal axis of the shank (14).

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