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] The present invention relates more particularly to hydraulic rotary impact hammer drills for use in drill rigs. [Background technology]

[0002] The drill rig comprises, in a known manner, a hydraulic rotary impact hammer drill slidably mounted on a slide and driving one or more drill burrs, the last of which carries a tool called a cutter that comes into contact with the rock. Generally, such hammer drills are intended to drill substantially deep holes, primarily to be able to place explosive loads there. The hammer drill is therefore the main element of the drill rig, which, on the one hand, provides rotation and impact via the drill burr to the cutter so as to penetrate the rock, and, on the other hand, supplies injection fluid to extract debris from the drilled hole.

[0003] More particularly, the hammer drill comprises a fluid injection portion including a longitudinal passage, a fluid supply inlet intended to be fluidly connected to a source of injection fluid, and an internal annular groove fluidly connected to the fluid supply inlet and opening into the longitudinal passage; and a shank intended to be coupled to a drill burr, the shank having a longitudinal axis and extending through the longitudinal passage of the fluid injection portion, the internal annular groove of the fluid injection portion extending around the shank, and the shank including a fluid injection conduit opening at a forward end of the shank and a communicating orifice configured to fluidly connect the internal annular groove and the fluid injection conduit.

[0004] Thus, injection fluid flows through the shank, drill burr and cutter, ejecting debris from the drilled material out of the hole during drilling.

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

[0006] All of the injection fluid used must contribute to debris evacuation. To this end, front and rear main seal gaskets, commonly referred to as "U" seal gaskets, are positioned on either side of an annular groove provided in the fluid injection section to contain the injection fluid in an injection chamber defined by the annular groove and the shank.

[0007] Given the rotational speed of the shank, the injection fluid pressure, the (sometimes approximate) surface condition of the shank, and possible axial offset of the shank caused by wear of the guide elements provided on the hammer drill, the front and rear main seal gaskets can wear and cause injection fluid to bleed out of the injection chamber, particularly in the direction of the pressurized and hydraulic areas of the hammer drill.

[0008] However, the presence of an incompressible, non-lubricating injection fluid in the aforementioned pressurized and hydraulic areas of a hammer drill can quickly lead to irreversible consequences for the hammer drill, resulting in immobilization of the hammer drill, production losses, and very high repair costs. Indeed, when a non-lubricating fluid penetrates the pressurized area of ​​a hammer drill, this fluid may enter, in particular, the hammer drill's rotary bearings, causing the hammer drill to jam. Depending on its nature, the injection fluid may corrode the inside of the hammer drill in the hydraulic area and possibly the bearing surfaces of the hydraulic gaskets, which may cause several hydraulic leaks and require the replacement of damaged parts other than the gaskets considered. Finally, if an incompressible fluid is present between the front of the striking piston and the bearing surface of the shank, i.e., at the boundary between the pressurized and hydraulic areas, the pressure of this injection fluid will increase significantly, which, given the very small clearance provided for the hammer drill, can cause the hammer drill's sealing gaskets to shift from their receiving housing and thus immediately block the hammer drill. However, such a jamming of the hammer drill results in significant repair costs.

[0009] To prevent the injection fluid from penetrating into the hammer drill, it is known to arrange a so-called backup additional seal gasket behind the rear main seal gasket and provide a fluid discharge orifice for the injection section, extending substantially radially between the rear main seal gasket and the rear backup seal gasket and opening into a leakage 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 leakage passage to exit the hammer drill due to leakage of the rear main seal gasket. Furthermore, it is assumed that the discharge of the injection fluid through this fluid discharge orifice will attract the operator's attention, allowing him to stop the hammer drill and replace the defective seal gasket.

[0010] Behind the rear backup seal gasket is the pressurized area mentioned above, which is typically swept by a compressible fluid flow that is lubricated to limit wear and corrosion, and the pressure of this compressible fluid limits the intrusion of the injection fluid into the pressurized area.

[0011] However, if the rear main seal gasket leaks and the injection fluid is under high pressure, the leakage will be realized by a wire-shaped or tube-shaped jet around the shank, over the angular portion of the shank, or even around its entire circumference. The jet generated in this manner has a very high velocity and therefore a very high dynamic pressure. This injection fluid jet can lift the rear backup seal gasket and flow between the rear backup seal gasket and the shank, thus penetrating the pressurized area where the static pressure is well below the dynamic pressure of the injection fluid. The hammer drill will then be filled with incompressible fluid and will be damaged very quickly. This phenomenon can occur at a static pressure measured at the leakage path that is lower than the pressurized pressure. Summary of the Invention [Problem to be solved by the invention]

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

[0013] The technical problem at the origin of the present invention is therefore to provide a hydraulic rotary impact hammer drill having a simple and economical structure, while limiting the risk of injection fluid entering the rear part of the shank and the interior of the hammer drill, which receives the striking piston of the hammer drill. [Means for solving the problem]

[0014] To this end, the present invention provides a hammer drill comprising: a hammer drill body; a fluid injection part provided at the front of the hammer drill body; a shank intended to be coupled to at least one drill burr equipped with a tool; a striking piston slidably mounted inside the hammer drill body along a striking axis and configured to abut against the shank; a front main seal gasket and a rear main seal gasket each annular and extending around the shank; a rear backup seal gasket also annular and extending around the shank; a leakage passage defined between the shank and the fluid injection part 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 part and fluidly connected to the leakage passage, wherein the fluid injection part includes a longitudinal passage, a fluid supply inlet intended to be fluidly connected to a source of injection fluid, and an annular internal groove fluidly connected to the fluid supply inlet and opening into the longitudinal passage; the annular internal groove extends around the shank, the shank including a fluid injection conduit extending over at least a portion of the length of the shank and a communicating orifice configured to fluidly connect the annular internal groove and the fluid injection conduit; the front and rear main seal gaskets are fixed to the fluid injection portion and are axially disposed on either side of the annular internal groove; the front and rear main seal gaskets are configured to tightly cooperate with a first shank portion of the shank; the rear backup seal gasket is disposed rearward of the rear main seal gasket and fixed to the fluid injection portion, the rear backup seal gasket being configured to tightly cooperate with a second shank portion of the shank; if injection fluid leaks into the rear main seal gasket, 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 generally cylindrical and has a first outer diameter, and the second shank portion is generally cylindrical and has a second outer diameter that is strictly greater than the first outer diameter; the hydraulic rotary impact hammer drill comprises 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 including a deviation surface provided on the shank and disposed (e.g., axially) between the first shank portion and the second shank portion, the deviation surface configured to deviate the leakage flow flowing into the leakage passage toward the rear backup seal gasket in a flow direction transverse to the longitudinal axis of the shank (i.e., intersecting the longitudinal axis of the shank).

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

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

[0018] Furthermore, given the reduction in dynamic pressure acting on the rear backup seal gasket due to possible leakage flow from the rear main seal gasket, the pressurization pressure prevailing behind the rear backup seal gasket will be sufficient to resist possible intrusion of injection fluid into the pressurized portion of the hammer drill.

[0019] As a result, the specific configuration of the hammer drill according to the invention makes it possible to provide improved reliability and safety in the use of the hammer drill.

[0020] Additionally, the hydraulic rotary impact hammer drill may have one or more of the following features, considered alone or in combination:

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

[0022] According to one embodiment of the present invention, the 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 transverse to, i.e., intersecting, the longitudinal axis of the shank.

[0023] According to one embodiment of the present invention, the deflection surface is configured to divert the leakage flow in 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 deflection surface extends toward the rear backup seal gasket while deviating from the longitudinal axis of the shank.

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

[0025] According to one embodiment of the invention, the deflection surface extends transversely to the longitudinal axis of the shank, i.e. according to an extension direction that intersects with the longitudinal axis of the shank.

[0026] According to one embodiment of the invention, the deflection surface is inclined relative to the longitudinal axis of the shank according to an inclination angle comprised between 1° and 89°, for example between 30° and 60°.

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

[0028] According to another embodiment of the 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 invention, the deflection surface diverges in the direction of the rear main seal gasket.

[0031] According to another embodiment of the invention, the deflection surface is at least partially defined by a concave portion that is curved and has a radius of curvature.

[0032] According to one embodiment of the 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 positioned (e.g., axially) between the first shank portion and the deflection surface, and the 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 extending at least partially around the shank and positioned (e.g., axially positioned) 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 invention, the exhaust chamber is annular.

[0036] According to one embodiment of the invention, the fluid inlet 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 divert the leakage flow flowing 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 disposed between the first and second shank portions, the connecting portion including an outer 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 outer circumferential 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 axially disposed between the rear main seal gasket and the rear backup seal gasket, and the rear intermediate portion includes an inner circumferential surface having 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 inner circumferential surface.

[0041] According to one embodiment of the present invention, the inner circumferential surface has a surface roughness that is higher than the surface roughness of the remaining inner circumferential surface 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 configured to rotationally drive the shank about a rotation axis substantially coincident with the striking axis.

[0043] According to one embodiment of the present invention, the hydraulic rotary impact hammer drill further comprises: a front backup seal gasket that is annular and extends around the shank; an additional leakage passage defined between the shank and the fluid injection portion 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 portion and fluidly connected to the additional leakage passage; and additional pressure drop generating means disposed in the additional leakage passage and configured to generate a pressure drop in the additional leakage passage when the leakage flow flows into the additional leakage passage, wherein the front backup seal gasket is disposed in front of the front main seal gasket and fixed to the fluid injection portion, and the front backup seal gasket is configured to tightly cooperate with a third shank portion of the shank, such that when injection fluid leaks into the front main seal gasket, the leakage flow will flow into the additional leakage passage, and the at least one additional fluid discharge orifice is configured to discharge the leakage flow flowing into the additional leakage passage to the outside of the hydraulic rotary impact hammer drill.

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

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

[0046] According to one embodiment of the present invention, the fluid injection section has a rear section 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 section is disposed behind the first and second sections.

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

[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 portion and arranged (e.g., arranged in the axial direction) between the first shank portion and the third shank portion, and the additional deflection surface is configured to redirect the leakage flow flowing through the additional leakage passage toward the front backup seal gasket in a flow direction transverse to the longitudinal axis of the shank (i.e., intersecting 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 transverse to, i.e., intersecting, the longitudinal axis of the shank.

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

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

[0052] According to one embodiment of the 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 invention, the additional deflection surface is inclined relative to the longitudinal axis of the shank according to an inclination angle comprised 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 exhaust chamber extending at least partially around the shank and positioned (e.g., axially positioned) between the front main seal gasket and the front backup seal gasket, and the at least one additional exhaust orifice opens into the additional exhaust chamber.

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

[0058] [Figure 1] FIG. 1 is a schematic longitudinal sectional view of a hydraulic rotary impact hammer drill according to a first embodiment of the present invention. [Figure 2] 2 is a partial longitudinal sectional view of the hydraulic rotary impact hammer drill of FIG. 1. FIG. [Figure 3] FIG. 3 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to a third embodiment of the present invention. [Figure 5] FIG. 5 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to a fourth embodiment of the present invention. [Figure 6] FIG. 6 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to a fifth embodiment of the present invention. [Figure 7] FIG. 7 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to a sixth embodiment of the present invention. [Figure 8]FIG. 8 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to a seventh embodiment of the present invention. [Figure 9] FIG. 9 is a partial vertical cross-sectional view of a hydraulic rotary impact hammer drill according to an eighth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0059] 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 comprises a hammer drill body 3 configured to be slidably mounted on a slide (not shown) provided on a carrier machine.

[0060] The hydraulic rotary impact hammer drill 2 comprises a striking system 4 including a striking piston 5 mounted to alternately slide within a piston cylinder 6 defined by the hammer drill body 3 along a striking axis A. The striking piston 5 and piston cylinder 6 define a first control chamber 7 which is annular and a second control chamber 8 which has a cross section larger than and opposed to the cross section of the first control chamber 7.

[0061] The striking system 4 further comprises a control distributor 9 arranged to control the alternating movement of the striking piston 5 inside the piston cylinder 6 according to alternating striking strokes and return strokes. The control distributor 9 is configured to define a second control chamber 8 in alternating connection with 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 with 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] A high pressure supply conduit 11 and a low pressure fluid return conduit 12 belong to the main hydraulic supply circuit comprising the percussion system 4 .

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

[0064] The shank 14 includes a fluid injection conduit 17 extending longitudinally and opening into the end face 16.1 of the second end 16. The shank 14 further includes communication orifices 18 opening radially into the fluid injection conduit 17 and into 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 removably attached to the front of the hammer drill body 3.

[0066] 1 and 2, the fluid injector 19 includes an injector body 21 that is generally tubular and disposed about the shank 14. The injector body 21 therefore includes a longitudinal passageway 22 through which the shank 14 extends.

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

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

[0069] According to the embodiment shown in Figures 1 and 2, the injector 21 has a first part 21.1 and a second part 21.2, each of which includes a first inner surface and a second inner surface that are substantially cylindrical, and the front and rear main seal gaskets 26, 27 are fixed in two annular fixing grooves provided in 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 disposed behind the rear main seal gasket 27 and is configured to tightly cooperate with the second shank portion 14.2 of the shank 14.

[0071] According to the embodiment shown in Figures 1 and 2, the injector 21 has a rear portion 21.3 including a rear inner surface that is generally cylindrical, and a rear backup seal gasket 28 is fixed in an annular fixing groove provided in the rear inner surface.

[0072] 1 and 2, the first shank portion 14.1 is generally cylindrical and has a first outer diameter, the second shank portion 14.2 is generally cylindrical and has a second outer diameter that is strictly greater than the first outer diameter, and the rear inner surface has an inner diameter that is greater than the inner diameter of the first inner surface.

[0073] Furthermore, the hydraulic rotary impact hammer drill 2 includes a leakage 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. In the event that injection fluid leaks into the rear main seal gasket 27, the leakage flow is intended to flow into the leakage passage 29.

[0074] 1 and 2, 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, and in particular includes a discharge chamber 31 that is annular and extends around the shank 14. The discharge chamber 31 is axially arranged 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 into the longitudinal passage 22 and partially defines 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] The hydraulic rotary impact hammer drill 2 also includes one or more fluid discharge orifices 33 provided in the injector 21 and opening, for example, radially, into the discharge chamber 31. Each fluid discharge orifice 33 is configured to discharge leakage flow 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 comprises a pressure drop generating means disposed in the leakage passage 29 and configured to generate a pressure drop in the leakage passage 29 when a leakage flow flows into the leakage passage 29.

[0077] According to the embodiment depicted in Figures 1 and 2, the pressure drop generating means comprises a deflection surface 34 which is annular and provided on the shank 14. The deflection surface 34 connects the first shank part 14.1 and the second shank part 14.2.

[0078] 1 and 2, the deflection surface 34 has a generally frustoconical shape and diverges in the direction of the rear backup seal gasket 28. 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°, and advantageously about 45°. 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 makes it possible to increase the pressure drop occurring in the leakage passage 29 even further.

[0079] More specifically, the deflection surface 34 is configured to redirect the leakage flow flowing in 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 FIG. 2, the deflection surface 34 is configured to redirect the leakage flow flowing in the leakage passage 29 in the direction of the rear backup seal gasket 28 toward the bottom wall of the annular discharge groove 32, thus causing the leakage flow to deviate from the longitudinal axis of the shank 14.

[0081] Therefore, if the rear main seal gasket 27 leaks and the injection fluid is high-pressure water, the water jet arising 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, combined with the expansion 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. Therefore, the pressurization pressure prevailing behind the rear backup seal gasket 28 will be sufficient to resist possible intrusion of the injection fluid into the pressurized part 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 rotationally drive the shank 14 about a rotation axis substantially coincident with the strike axis A. For example, the rotary drive system 35 includes a coupling member 36, such as a coupling pinion, that is tubular and disposed around the shank 14. The coupling member 36 includes male and female coupling splines that are rotationally coupled with female and male coupling splines, respectively, provided on the shank 14.

[0083] Advantageously, the coupling member 36 comprises an outer circumferential toothing that is rotationally coupled to the output shaft of a drive motor 37, such as a hydraulic motor, that 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 comprise an intermediate pinion 38 that is coupled to the output shaft of the drive motor 37 on the one hand and to the outer circumferential toothing of the coupling member 36 on the other hand.

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

[0085] FIG. 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 injector 21 does not have the annular discharge groove 32.

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

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

[0088] 6 shows a fifth embodiment of the hydraulic rotary impact hammer drill 2 according to the present invention, which differs from the third embodiment essentially in that the shank 14 includes an annular groove 39 on the outer surface of the shank 14 and arranged axially between the first shank part 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 part 14.1. Such a configuration of the shank 14 makes it possible to increase the pressure drop occurring in the leakage passage 29 even further.

[0089] FIG. 7 shows a hydraulic rotary impact hammer drill 2 according to a 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 differs essentially from the first embodiment in that the hydraulic rotary impact hammer drill 2 further comprises a front backup seal gasket 44 that is annular and extends around the shank 14, the front backup seal gasket 44 being arranged in front of the front main seal gasket 26 and configured to tightly cooperate with the third shank portion 14.3 of the shank 14.

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

[0092] According to the embodiment depicted in FIG. 8, the third shank portion 14.3 is generally cylindrical and has a third outer diameter substantially identical to the first outer diameter of the first shank portion 14.1, and the front inner surface has an inner diameter substantially identical to the inner diameter of the first inner surface.

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

[0094] 8, the additional leakage passage 45 has a passage cross section that varies 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 arranged 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 into the longitudinal passage 22 and partially defines 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 injector 21 and opening, for example radially, into the additional discharge chamber 46. Each additional fluid discharge orifice 48 is configured to discharge leakage flow flowing through the additional leakage passage 45 to the outside of the hydraulic rotary impact hammer drill 2.

[0096] 8, the injector 21 includes a pressure channel 49 extending over at least a portion of the length of the body and opening substantially radially onto the front inner surface. Such pressure channel 49 is supplied with a pressurized fluid, typically compressible and ideally lubricated, making it possible to limit rotational and translational friction between the shank 14 and the injector 21.

[0097] FIG. 9 shows an eighth embodiment of the hydraulic rotary impact hammer drill 2 according to the present invention, which differs from the seventh embodiment essentially 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 comprises additional pressure drop generating means arranged in the additional leakage passage 45 and 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 depicted in Figure 9, the pressure drop generating means comprises an additional deflection surface 51 which is annular and provided on the injector 21. The additional deflection surface 51 connects the front inner surface to the first inner surface.

[0099] 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 in 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 variant of the 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 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°, advantageously about 45°.

[0101] Therefore, if the front main seal gasket 26 leaks 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 therefore reduce the dynamic pressure acting on the front backup seal gasket 44. Therefore, the injection fluid leaking 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, and its service life will be significantly extended.

[0102] Furthermore, given that the dynamic pressure exerted by the injection fluid at the front backup seal gasket 44 is significantly reduced, the pressurization pressure prevailing in front of the front backup seal gasket 44 will be sufficient to limit the risk of leakage fluid entering via pressurization channels in the pressurized area or hydraulic area of ​​the hydraulic rotary impact hammer drill due to the presence of the pressurization channel 49. The presence of the additional deflection surface 51 therefore makes it possible to further increase the reliability of the hydraulic rotary impact hammer drill 2 according to the present invention.

[0103] According to another variant of the invention, the additional deflection surface 51 may converge in the direction of the front main seal gasket 26 and may be configured to direct the leakage flow that flows in the direction of the front backup seal gasket 44 into the additional leakage passage 45 towards the front main seal gasket 26. According to such an embodiment of the invention, the additional deflection surface 51 is inclined relative to the longitudinal axis of the shank 14 according to an inclination angle comprised between 91° and 179°, for example between 120° and 150°, advantageously about 135°.

[0104] According to a variation of the present invention, the injector 21 may include a rear intermediate portion that would be axially disposed between the rear main seal gasket 27 and the rear backup seal gasket 28, and the rear intermediate portion 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 leakage flow flows into the leakage passage 29. According to such a variation 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 invention, the shank 14 may include, in addition to the deflection surface 34, a connecting portion axially disposed between the first and second shank portions, the connecting portion including an outer circumferential 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) if leakage flow enters the leakage passage. According to this variant of the invention, the pressure drop generating means would be formed by the deflection surface 34 and the surface roughness of the outer circumferential surface.

[0106] Needless to say, the present invention is not limited to the only embodiment of this hydraulic rotary impact hammer drill described above by way of example, but on the contrary covers all its variants.

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 annular and extending 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 portion (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 inner groove (25), and the front and rear main seal gaskets (26, 27) are 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), and the rear backup seal gasket (28) is configured to tightly cooperate with a second shank portion (14.2) of the shank (14); When injection fluid leaks into the rear main seal gasket (27), the 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 flowing through the leakage passage (29) to the outside of the hydraulic rotary impact hammer drill (2). A hydraulic rotary impact hammer drill (2), 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 that is strictly greater than the first outer diameter; the hydraulic rotary impact hammer drill (2) comprises 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 flowing into the leakage passage (29) toward 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 so 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) according to any one of claims 1 to 3, wherein the deflection surface (34) is annular.

5. 4. A hydraulic rotary impact hammer drill (2) according to 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) according to claim 1, wherein the shank (14) has a deflection collar (41) provided on the 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) according to 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 disposed axially between the first and second shank portions (14.1, 14.2), the connection portion including an outer peripheral 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 peripheral 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), and the rear intermediate portion includes 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 front main seal gasket (26) to the front 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 generating means disposed in the additional leakage passage (45) and configured to generate a pressure drop in the additional leakage passage (45) when the leakage flow flows through the additional leakage passage (45); Furthermore, 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), and the front backup seal gasket (44) is configured to tightly cooperate with a third shank portion (14.3) of the shank (14); When 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 claim 1, wherein the at least one additional fluid discharge orifice (48) is configured to discharge the leakage flow flowing through the additional leakage passage (45) to the outside of 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 includes an additional deflection surface (51) provided in 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 through 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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