Hydraulic rotary hammer drill

Abstract

A hydraulic rotary percussive hammer drill comprises a fluid injection portion comprising a fluid feed inlet (23) and an annular inner recess (25) in fluid connection with the fluid feed inlet, a shank portion (14) comprising a fluid injection conduit (17) in fluid connection with the annular inner recess (25), a front main sealing washer and a rear main sealing washer (26, 27) arranged on either side of the annular inner recess (25) and configured to cooperate with a first shank portion (14.1) of the shank portion (14), a rear back-up sealing washer (28) located rearward of the rear main sealing washer (27) and configured to cooperate with a second shank portion (14.2) of the shank portion (14), a leakage passage (29) defined between the shank portion (14) and the fluid injection portion, pressure drop generating means configured to generate a pressure drop in the leakage passage (29) when a leakage flow is flowing in the leakage passage (29).

Description

Technical Field

[0001] This invention relates to a hydraulic rotary impact hammer drill, and more specifically to a hydraulic rotary impact hammer drill used on a drilling rig. Background Technology

[0002] In known methods, drilling rigs include hydraulic rotary impact hammer drills, which are slidably mounted on a sliding element and drive one or more drill rods, the last of which carries a tool called a cutter that contacts the rock. Generally, such hammer drills are primarily used for drilling deep holes to allow for the placement of explosive loads. Therefore, the hammer drill is a key component of the drilling rig; on the one hand, it applies rotation and impact to the cutter via the drill rods to penetrate the rock, and on the other hand, it supplies injection fluid to remove debris from the borehole.

[0003] More specifically, the hammer drill includes:

[0004] - A fluid injection section, comprising a longitudinal passage, a fluid inlet for fluid connection to an injection fluid source, and an annular inner groove fluidly connected to the fluid inlet and leading to the longitudinal passage, and

[0005] - A shank for connection with a drill pipe, the shank having a longitudinal axis and extending in a longitudinal passage of a fluid injection portion such that an annular groove of the fluid injection portion extends around the shank, the shank including a fluid injection conduit opening at a front end of the shank, and a communication orifice configured to fluidly connect the annular groove and the fluid injection conduit.

[0006] Therefore, the injected fluid flows through the shank, drill rod, and cutter, and removes debris of the material to be drilled from the hole during drilling.

[0007] In some applications, particularly in mines and underground quarries, water forms this injection fluid, which allows rock dust to be prevented from spreading into the atmosphere as it exits the borehole during drilling.

[0008] All injected fluid used should be used to expel debris. To this end, the front main sealing gasket and the rear main sealing gasket (commonly referred to as "U"-shaped sealing gaskets) are arranged on both sides of the annular groove (which is located in the fluid injection section) to contain the injected fluid in the injection chamber defined by the annular groove and the handle.

[0009] Considering the rotational speed of the shank, the pressure of the injected fluid, the surface condition of the shank (sometimes rough), and the possible axial misalignment of the shank caused by the wear of the guide elements set on the hammer drill, the front and rear master seal gaskets may wear, and may cause the injected fluid to flow out of the injection chamber, especially in the direction of the pressurized and hydraulic areas of the hammer drill.

[0010] However, the presence of incompressible and non-lubricating injected fluid in the pressurized and hydraulic zones of the hammer drill can cause irreversible consequences, resulting in limited drill movement, production losses, and very high maintenance costs. In fact, when the non-lubricating fluid seeps into the pressurized zone of the hammer drill, it can particularly enter the rotary bearings and potentially cause the drill to jam. Depending on its nature, the injected fluid may corrode the interior of the hammer drill in the hydraulic zone and may also corrode the support surfaces of the hydraulic gaskets, leading to hydraulic leaks and requiring replacement of damaged parts other than the gaskets involved. Finally, if the incompressible fluid is located between the front of the impact piston and the receiving surface of the shank, thus at the boundary between the pressurized and hydraulic zones, the pressure of the injected fluid will increase significantly. Given the very small clearance provided in the hammer drill, this can cause the sealing gaskets to displace from their receiving housings, thus immediately blocking the drill. This blockage of the hammer drill will result in considerable maintenance costs.

[0011] To prevent injected fluid from penetrating the internal parts of the hammer drill, it is known to place a so-called spare auxiliary sealing gasket behind the rear main sealing gasket, and to provide a fluid discharge orifice on the injection section and between the rear main sealing gasket and the rear spare sealing gasket. This fluid discharge orifice extends substantially radially and leads to a leakage path defined by the functional gap between the shank and the injection section. Due to leakage from the rear main sealing gasket, this fluid discharge orifice allows injected fluid flowing in the leakage path to flow out of the hammer drill. Furthermore, the injected fluid discharged through this fluid discharge orifice should draw the operator's attention, causing him to stop the hammer drill and replace the defective sealing gasket.

[0012] The aforementioned pressurized zone is located behind the rear spare sealing gasket and is swept by a flow of compressible fluid (typically lubricating to limit wear and corrosion). The pressure of this compressible fluid limits the penetration of the injection fluid into the pressurized zone.

[0013] However, in the event of a leak in the rear main sealing gasket and under high pressure from the injected fluid, the leak occurs as a linear or tubular jet around the shank, at an angled portion of the shank, or along its entire circumference. The jet produced in this way has a very high velocity and therefore a very high dynamic pressure. This injected fluid jet may lift the rear spare sealing gasket, flow between the rear spare sealing gasket and the shank, and thus penetrate into the pressurized area, where the static pressure is much lower than the dynamic pressure of the injected fluid. The hammer drill is then filled with an incompressible fluid and quickly fails. This phenomenon can also occur, although the static pressure measured in the leak path may be lower than the pressurized pressure.

[0014] The present invention aims to overcome these shortcomings. Summary of the Invention

[0015] Therefore, the technical problem from which this invention originates is to provide a hydraulic rotary impact hammer drill with a simple and economical structure, while limiting the risk of injected fluid penetrating into the internal part of the hammer drill, which receives the impact piston and the rear part of the shank of the hammer drill.

[0016] Therefore, the present invention relates to a hydraulic rotary impact hammer drill, comprising:

[0017] -Hammer drill body,

[0018] - A fluid injection section is provided on the front part of the hammer drill body. The fluid injection section includes a longitudinal passage, a fluid inlet for fluid connection with the injection fluid source, and an annular inner groove that is fluidly connected to the fluid inlet and leads to the longitudinal passage.

[0019] - A shank for connection with at least one drill pipe equipped with a tool, the shank having a longitudinal axis and extending in a longitudinal passage of a fluid injection portion, an annular groove extending 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 groove and the fluid injection conduit.

[0020] - An impact piston, which is slidably mounted in the hammer drill body along the impact axis and configured to strike the shank.

[0021] - A front main sealing washer and a rear main sealing washer, which are annular and each extends around the shank. The front and rear main sealing washers are fastened to the fluid injection portion and are axially positioned on both sides of the annular inner groove. The front and rear main sealing washers are configured to fit tightly with the first shank portion of the shank.

[0022] - A rear spare sealing gasket, which is annular and extends around the handle, is located behind the rear main sealing gasket and is fastened to the fluid injection portion. The rear spare sealing gasket is configured to fit tightly with the second handle portion of the handle.

[0023] - A leakage path, defined between the handle and the fluid injection portion and extending from the rear main sealing gasket to the rear spare sealing gasket, allows leakage flow to occur in the leakage path should a leaking fluid leak occur at the rear main sealing gasket.

[0024] - At least one fluid discharge orifice, disposed on the fluid injection section and fluidly connected to the leakage path, said at least one fluid discharge orifice being configured to discharge the leakage flow flowing in the leakage path outside the hydraulic rotary impact hammer drill.

[0025] The invention is characterized in that 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 significantly larger than the first outer diameter. The hydraulic rotary impact hammer drill includes a pressure drop generating device disposed in a leakage passage and configured to generate a pressure drop in the leakage passage when a leakage flow flows in the leakage passage. The pressure drop generating device includes a deflecting surface disposed on the shank and located (e.g., axially) between the first and second shank portions. The deflecting surface is configured to redirect a leakage flow flowing in the leakage passage toward a rear backup gasket into a flow direction transverse to the longitudinal axis of the shank (i.e., the flow direction intersects the longitudinal axis of the shank).

[0026] In the event of leakage in the rear main gasket, the presence of this pressure drop generating device within the leakage path will allow for a significant reduction in the flow velocity of the leakage flow from the rear main gasket to the rear spare gasket, and thus a significant reduction in the dynamic pressure applied to the rear spare gasket.

[0027] Therefore, the specific configuration of the hammer drill according to the present invention extends the service life of the rear spare sealing gasket, thereby reducing the replacement frequency of the rear spare sealing gasket.

[0028] Furthermore, given the reduced dynamic pressure exerted on the rear spare gasket by the possible leakage flow from the rear main gasket, the dominant boost pressure at the rear of the rear spare gasket will be sufficient to prevent any injection fluid from entering the boost section of the hammer drill.

[0029] Therefore, the specific configuration of the hammer drill according to the present invention allows for enhanced reliability and safety in use.

[0030] Hydraulic rotary impact hammer drills may further have one or more of the following features, either individually or in combination.

[0031] According to one embodiment of the invention, the pressure drop generating device is configured such that the leakage path has a path cross-section that varies between the rear primary sealing gasket and the rear backup sealing gasket.

[0032] According to one embodiment of the invention, the deflecting surface is configured to redirect the leakage flow from a flow direction substantially parallel to the longitudinal axis of the handle to a flow direction transverse to the longitudinal axis of the handle, that is, the flow direction intersecting the longitudinal axis of the handle.

[0033] According to one embodiment of the invention, the deflecting surface is configured to redirect the leakage flow in the leakage path toward the rear spare gasket, causing the leakage flow to deviate, i.e., away from the longitudinal axis of the handle. In other words, the deflecting surface extends toward the rear spare gasket while deviating from the longitudinal axis of the handle.

[0034] According to one embodiment of the invention, the deflection surface is annular.

[0035] According to one embodiment of the invention, the deflection surface extends transversely to the longitudinal axis of the handle, that is, it extends in a direction intersecting the longitudinal axis of the handle.

[0036] According to one embodiment of the invention, the deflecting surface is tilted relative to the longitudinal axis of the handle at a certain tilt angle, which includes between 1° and 89°, for example between 30° and 60°.

[0037] According to one embodiment of the invention, the deflection surface has a generally truncated conical shape.

[0038] According to another embodiment of the invention, the deflection surface extends substantially perpendicular to the longitudinal axis of the handle.

[0039] According to another embodiment of the invention, the deflection surface diverges in the direction of the rear spare sealing gasket.

[0040] According to another embodiment of the invention, the deflection surface diverges in the direction of the rear main sealing gasket.

[0041] According to another embodiment of the invention, the deflection surface is at least partially formed by a curved concave surface portion having a radius of curvature.

[0042] According to one embodiment of the invention, the handle includes a deflection collar disposed on the outer surface of the handle and including a deflection surface.

[0043] According to one embodiment of the invention, the handle includes an annular groove disposed on the outer surface of the handle and located (e.g., axially) between a first handle portion and a deflection surface, the minimum diameter of the annular groove being smaller than a first outer diameter of the first handle portion.

[0044] According to one embodiment of the invention, the leakage path includes a discharge chamber that extends at least partially around the handle and is located (e.g., axially) between a rear primary sealing gasket and a rear spare sealing gasket, with at least one fluid discharge orifice leading to the discharge chamber.

[0045] According to one embodiment of the invention, the discharge chamber is annular.

[0046] According to one embodiment of the invention, the fluid injection portion includes an annular discharge groove that leads to a longitudinal passage and partially defines a discharge chamber.

[0047] According to one embodiment of the invention, the deflection surface is configured to redirect the leakage flow flowing in the leakage path along the direction of the rear spare sealing gasket toward the bottom wall of the annular discharge groove.

[0048] According to one embodiment of the invention, the handle includes a connecting portion located axially between a first handle portion and a second handle portion, the connecting portion including an outer peripheral surface having a certain surface roughness configured to generate a pressure drop in the leakage path when a leakage flow flows in the leakage path, the pressure drop generating device being formed at least partially by the surface roughness of the outer peripheral surface.

[0049] According to one embodiment of the present invention, the outer peripheral surface of the connecting portion has a surface roughness higher than that of the outer peripheral surfaces of the first shank portion and the second shank portion.

[0050] According to one embodiment of the invention, the fluid injection portion includes a rear intermediate portion located axially between a rear primary sealing gasket and a rear spare sealing gasket. The rear intermediate portion includes an inner circumferential surface having a certain surface roughness configured to generate a pressure drop in the leakage path when the leakage flow flows in the leakage path. The pressure drop generating device is at least partially formed by the surface roughness of the inner circumferential surface.

[0051] According to one embodiment of the present invention, the inner peripheral surface has a surface roughness higher than that of other inner peripheral surfaces of the fluid injection portion.

[0052] According to one embodiment of the invention, the hydraulic rotary impact hammer drill further includes a rotary drive device configured to drive the shank to rotate about a rotation axis substantially coincident with the impact axis.

[0053] According to one embodiment of the present invention, the hydraulic rotary impact hammer drill further comprises:

[0054] - A front spare sealing gasket, which is annular and extends around the handle, is located in front of the front main sealing gasket and is fastened to the fluid injection portion. This front spare sealing gasket is configured to fit tightly with the third handle portion of the handle.

[0055] - An additional leakage path, defined between the handle and the fluid injection portion and extending from the front main sealing gasket to the front spare sealing gasket, allows leakage flow to occur in the additional leakage path should a leak of injected fluid occur at the front main sealing gasket.

[0056] - At least one additional fluid discharge orifice, disposed on the fluid injection section and fluidly connected to an additional leakage passage, said at least one additional fluid discharge orifice being configured to discharge leakage flow flowing in the additional leakage passage outside the hydraulic rotary impact hammer drill.

[0057] - An additional pressure drop generating device is disposed in the additional leakage path and configured to generate a pressure drop in the additional leakage path when the leakage flow flows in the additional leakage path.

[0058] According to one embodiment of the invention, the third handle portion is generally cylindrical and has a third outer diameter that is strictly smaller than the first outer diameter.

[0059] According to one embodiment of the present invention, the fluid injection portion includes a first portion and a second portion, the first portion and the second portion respectively including a first inner surface and a second inner surface that are generally cylindrical, and a front main sealing gasket and a rear main sealing gasket are fastened in two annular fastening grooves respectively provided on the first inner surface and the second inner surface.

[0060] According to one embodiment of the invention, the fluid injection portion includes a rear portion having a generally cylindrical rear inner surface, and a rear spare sealing gasket is fastened in an annular fastening groove disposed on the rear inner surface. The rear portion is located at the rear of the first portion and the second portion.

[0061] According to one embodiment of the invention, the fluid injection portion includes a front portion having a generally cylindrical front inner surface, and a front spare sealing gasket is fastened in an annular fastening groove disposed on the front inner surface. The front portion is located at the front of the first portion and the second portion.

[0062] According to one embodiment of the invention, the additional pressure drop generating device includes an additional deflection surface disposed on the fluid injection portion and located (e.g., axially) between the first and third stem portions. The additional deflection surface is configured to redirect a leakage flow in the additional leakage path toward the front spare gasket to a flow direction transverse to the longitudinal axis of the stem, that is, the flow direction intersecting the longitudinal axis of the stem.

[0063] According to one embodiment of the invention, the additional deflection surface is configured to redirect the leakage flow from a flow direction substantially parallel to the longitudinal axis of the handle to a flow direction transverse to the longitudinal axis of the handle, that is, the flow direction intersecting the longitudinal axis of the handle.

[0064] According to one embodiment of the invention, the additional deflection surface is configured to redirect the leakage flow toward the longitudinal axis of the handle.

[0065] According to one embodiment of the present invention, the inner diameter of the front inner surface is smaller than the inner diameter of the first inner surface.

[0066] According to one embodiment of the invention, the additional deflection surface is annular and connects the front inner surface to the first inner surface.

[0067] According to one embodiment of the invention, the additional deflection surface is tilted relative to the longitudinal axis of the handle at a certain tilt angle, which is included between 1° and 89°, for example between 30° and 60°.

[0068] According to one embodiment of the invention, the additional deflection surface converges in the direction toward the front main sealing gasket.

[0069] According to one embodiment of the invention, the additional deflection surface converges in the direction toward the front spare sealing gasket.

[0070] According to one embodiment of the invention, the additional leakage path includes an additional vent chamber that extends at least partially around the handle and is located (e.g., axially) between a front primary sealing gasket and a front spare sealing gasket, with at least one additional vent orifice leading to the additional vent chamber. Attached Figure Description

[0071] The invention will be better understood from the following description with reference to the accompanying drawings, wherein the same reference numerals correspond to structurally and / or functionally identical or similar elements.

[0072] Figure 1 This is a schematic longitudinal sectional view of a hydraulic rotary impact hammer drill according to a first embodiment of the present invention.

[0073] Figure 2 yes Figure 1 A partial longitudinal sectional view of a hydraulic rotary impact hammer drill.

[0074] Figure 3 This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to a second embodiment of the present invention.

[0075] Figure 4 This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to a third embodiment of the present invention.

[0076] Figure 5 This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to a fourth embodiment of the present invention.

[0077] Figure 6 This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to the fifth embodiment of the present invention.

[0078] Figure 7This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to the sixth embodiment of the present invention.

[0079] Figure 8 This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to the seventh embodiment of the present invention.

[0080] Figure 9 This is a partial longitudinal sectional view of a hydraulic rotary impact hammer drill according to the eighth embodiment of the present invention. Detailed Implementation

[0081] Figure 1 and Figure 2 A first embodiment of a hydraulic rotary impact hammer drill 2 is shown, which is used 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 sliding member (not shown) provided on a transport vehicle.

[0082] The hydraulic rotary impact hammer drill 2 includes an impact system 4, which includes an impact piston 5 mounted to alternately slide along an impact axis A within a piston cylinder 6 defined by the hammer drill body 3. The impact piston 5 and the piston cylinder 6 define a first control chamber 7 and a second control chamber 8. The first control chamber is annular, and the second control chamber has a cross-section larger than that of the first control chamber 7 and is opposite to the first control chamber 7.

[0083] The impact system 4 further includes a control distributor 9, which is arranged to alternately control the impact piston 5 to move alternately within the piston cylinder 6 according to the impact stroke and return stroke. The control distributor 9 is configured to set a second control chamber 8 to alternately connect to a high-pressure fluid inlet conduit 11 (e.g., a high-pressure incompressible fluid inlet conduit) during the impact stroke of the impact piston 5 and to a low-pressure fluid return conduit 12 (e.g., a low-pressure incompressible fluid return conduit) during the return stroke of the impact piston 5. Advantageously, the first control chamber 7 is permanently supplied with high-pressure fluid via an inlet channel 13 connected to the high-pressure fluid inlet conduit 11.

[0084] The high-pressure feed pipe 11 and the low-pressure fluid return pipe 12 belong to the main hydraulic feed circuit provided to the impact system 4.

[0085] The hydraulic rotary impact hammer drill 2 further includes a shank 14 for attachment in a known manner to at least one drill rod (not shown) equipped with a tool (also referred to as a cutter). The shank 14 extends longitudinally along a longitudinal axis (advantageously coinciding with the impact axis A) and includes a first end portion 15 and a second end portion 16. The first end portion points toward an impact piston 5 and is provided with an end face 15.1, which the impact piston 5 strikes during each operating cycle of the hydraulic rotary impact hammer drill 2. The second end portion, opposite to the first end portion 15, is for attachment to at least one drill rod.

[0086] The handle 14 includes a fluid injection conduit 17 that extends longitudinally and leads to an end face 16.1 of the second end portion 16. Furthermore, the handle 14 includes a communication orifice 18 that radially leads to both the fluid injection conduit 17 and the outer surface of the handle 14.

[0087] The hydraulic rotary impact hammer drill 2 further includes a fluid injection portion 19 disposed on the front portion of the hammer drill body 3. For example, the fluid injection portion 19 may be removably mounted on the front portion of the hammer drill body 3.

[0088] according to Figure 1 and Figure 2 In the illustrated embodiment, the fluid injection portion 19 includes an injection body 21, which is generally tubular and disposed around a handle 14. Therefore, the injection body 21 includes a longitudinal passage 22 in which the handle 14 extends.

[0089] The injection body 21 further includes a fluid inlet 23 fluidly connected to a fluid delivery conduit 24 and an annular groove 25 connected to an injection fluid source. The annular groove extends around the handle 14, and the fluid inlet 23 leads to the bottom of the annular groove. A communication orifice 18 on the handle 14 leads to the annular groove 25, allowing the fluid injection conduit 17 to be fluidly connected to the fluid delivery conduit 24 via the annular groove 25 and the fluid inlet 23. For example, the injection fluid delivered by the fluid delivery conduit 24 may consist of water or air.

[0090] Furthermore, the hydraulic rotary impact hammer drill 2 includes a front main sealing washer 26 and a rear main sealing washer 27, which are annular and each extends around the shank 14. The front and rear main sealing washers 26 and 27 are axially disposed on both sides of the annular groove 25 and configured to fit tightly with the first shank portion 14.1 of the shank 14. For example, each of the front and rear main sealing washers 26 and 27 may have a generally U-shaped cross-section and include an annular sealing lip configured to fit tightly with the first shank portion 14.1.

[0091] according to Figure 1 and Figure 2 In one embodiment shown, the injection body 21 includes a first part 21.1 and a second part 21.2. The first part and the second part respectively include a first inner surface and a second inner surface that are generally cylindrical. The front main sealing gasket and the rear main sealing gaskets 26 and 27 are fastened in two annular fastening grooves respectively provided on the first inner surface and the second inner surface.

[0092] The hydraulic rotary impact hammer drill 2 also includes a rear spare sealing washer 28, which is annular and extends around the shank 14. The rear spare sealing washer 28 is located behind the rear main sealing washer 27 and is configured to fit tightly with the second shank portion 14.2 of the shank 14.

[0093] according to Figure 1 and Figure 2 In the embodiment shown, the injection body 21 includes a rear portion 21.3, which includes a generally cylindrical rear inner surface, and a rear spare sealing gasket 28 is fastened in an annular fastening groove provided on the rear inner surface.

[0094] according to Figure 1 and Figure 2 In the illustrated embodiment, the first handle portion 14.1 is generally cylindrical and has a first outer diameter, and the second handle portion 14.2 is generally cylindrical and has a second outer diameter that is significantly 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.

[0095] Furthermore, the hydraulic rotary impact hammer drill 2 includes a leakage passage 29 defined between the shank 14 and the injection body 21 and extending from the rear main sealing gasket 27 to the rear spare sealing gasket 28. In the event of an injection fluid leak at the rear main sealing gasket 27, the leaking flow will occur in the leakage passage 29.

[0096] according to Figure 1 and Figure 2 In the illustrated embodiment, the leakage passage 29 has a passage cross-section that varies between the rear primary sealing gasket 27 and the rear backup sealing gasket 28, and specifically includes a discharge chamber 31 that is annular and extends around the handle 14. The discharge chamber 31 is axially located between the rear primary sealing gasket 27 and the rear backup sealing gasket 28. Advantageously, the injection body 21 includes an annular discharge groove 32 that leads to 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 gap between the first handle portion 14.1 and the second inner surface, and a downstream passage portion defined by a functional gap between the second handle portion 14.2 and the rear inner surface.

[0097] The hydraulic rotary impact hammer drill 2 also includes one or more fluid discharge ports 33, which are disposed on the injection body 21 and, for example, open radially to the discharge chamber 31. The fluid discharge ports or each fluid discharge port 33 are configured to discharge the leakage flow flowing in the leakage passage 29 outside the hydraulic rotary impact hammer drill 2.

[0098] The hydraulic rotary impact hammer drill 2 further includes a pressure drop generating device disposed in the leakage passage 29 and configured to generate a pressure drop in the leakage passage 29 when the leakage flow flows in the leakage passage 29.

[0099] according to Figure 1 and Figure 2 In the illustrated embodiment, the voltage drop generating device includes a deflection surface 34, which is annular and disposed on the shank 14. The deflection surface 34 connects the first shank portion 14.1 to the second shank portion 14.2.

[0100] according to Figure 1 and Figure 2 In the illustrated embodiment, the deflecting surface 34 has a generally frustoconical shape and diverges in the direction of the rear spare sealing gasket 28. The deflecting surface 34 is inclined at a certain angle relative to the longitudinal axis of the handle 14, the angle being between 1° and 89°, for example between 30° and 60°, advantageously about 45°. However, according to one embodiment of the invention, the deflecting surface 34 may extend substantially perpendicular to the longitudinal axis of the handle 14. This configuration of the deflecting surface 34 allows for a further increase in the pressure drop generated within the leakage path 29.

[0101] More specifically, the deflection surface 34 is configured to change the flow direction of the leakage flow in the leakage channel 29 toward the rear spare sealing gasket 28 from a flow direction substantially parallel to the longitudinal axis of the handle 14 to a flow direction transverse to the longitudinal axis of the handle 14, that is, the flow direction intersecting the longitudinal axis of the handle 14.

[0102] according to Figure 2 In the embodiment shown, the deflection surface 34 is configured to deflect the leakage flow flowing in the direction of the rear spare sealing gasket 28 in the leakage passage 29 toward the bottom wall of the annular discharge groove 32, and thus cause the leakage flow to deviate from the longitudinal axis of the handle 14.

[0103] Therefore, in the event of leakage at the rear main sealing gasket 27 and the injection fluid being high-pressure water, the water jet originating from the rear main sealing gasket 27 will be deflected at least once by the deflecting surface 34 on the shank 14, and a second time by the bottom wall of the annular discharge groove 32 before being loaded onto the rear spare sealing gasket 28. These pressure drops, coupled with the enlargement of the cross-section of the leakage passage 29 at the discharge chamber 31, will significantly limit the flow velocity of the water jet and thus reduce the dynamic pressure applied to the rear spare sealing gasket 28. Therefore, the dominant boosting pressure at the rear of the rear spare sealing gasket 28 will be sufficient to prevent any possible injection fluid from intruding into the pressurized portion of the hydraulic rotary impact hammer drill 2.

[0104] The hydraulic rotary impact hammer drill 2 also includes a rotary drive system 35 configured to drive the shank 14 to rotate about a rotation axis substantially coincident with the impact axis A. For example, the rotary drive system 35 includes a connecting member 36 (e.g., a connecting pinion) that is tubular and arranged around the shank 14. The connecting member 36 includes a male connecting spline and a female connecting spline, which are rotatably connected to the female connecting spline and the male connecting spline respectively provided on the shank 14.

[0105] Advantageously, the connecting member 36 includes an outer peripheral gear rotatably connected to the output shaft of the drive motor 37 (e.g., a hydraulic motor whose hydraulic power is supplied by an external hydraulic power supply circuit), which belongs to the rotary drive system 35. For example, the rotary drive system 35 may include an intermediate pinion 38, which is connected to the output shaft of the drive motor 37 on one hand and to the outer peripheral gear of the connecting member 36 on the other.

[0106] When the hydraulic rotary impact hammer drill 2 is running, the shank 14 rotates due to the drive motor 37, and the shank 14 receives the cyclic impact of the impact piston 5 on its end face 15.1, which is ensured by the impact system 4 supplied by the main hydraulic feed circuit.

[0107] Figure 3 A hydraulic rotary impact hammer drill 2 according to a second embodiment of the present invention is shown, which differs from the first embodiment mainly in that the injection body 21 does not have an annular discharge groove 32.

[0108] Figure 4A hydraulic rotary impact hammer drill 2 according to a third embodiment of the invention is shown, which differs from the first embodiment primarily in that the deflecting surface 34 is configured to guide the leakage flow flowing in the leakage passage 29 along the direction of the rear spare sealing gasket 28 toward the rear main sealing gasket 27. This configuration of the deflecting surface 34 allows for a further increase in the pressure drop generated within the leakage passage 29. According to this embodiment of the invention, the deflecting surface 34 diverges in the direction of the rear main sealing gasket 27. According to this embodiment of the invention, the deflecting surface 34 is inclined relative to the longitudinal axis of the shank 14 at a certain angle, which is included between 91° and 179°, for example between 120° and 150°, advantageously about 135°.

[0109] Figure 5 The present invention illustrates a hydraulic rotary impact hammer drill 2 according to a fourth embodiment, which differs from the second embodiment primarily in that the deflection surface 34 is at least partially formed by a curved concave surface portion having a radius of curvature.

[0110] Figure 6 A hydraulic rotary impact hammer drill 2 according to a fifth embodiment of the invention is shown, which differs from the third embodiment primarily in that the shank 14 includes an annular groove 39 disposed on the outer surface of the shank 14 and axially located 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. This configuration of the shank 14 allows for a further increase in the pressure drop generated within the leakage passage 29.

[0111] Figure 7 A hydraulic rotary impact hammer drill 2 according to a sixth embodiment of the present invention is shown, which differs from the first embodiment mainly in that the shank 14 includes a deflection collar 41 disposed on the outer surface of the shank 14 and includes a deflection surface 34.

[0112] Figure 8 A hydraulic rotary impact hammer drill 2 according to a seventh embodiment of the present invention is shown, which differs from the first embodiment mainly in that the hydraulic rotary impact hammer drill 2 further includes a front spare sealing washer 44, which is annular and extends around the shank 14. The front spare sealing washer 44 is located at the front of the front main sealing washer 26 and is configured to fit tightly with the third shank portion 14.3 of the shank 14.

[0113] according to Figure 8 In the embodiment shown, the injection body 21 includes a front portion 21.4, which includes a generally cylindrical front inner surface, and a front spare sealing gasket 44 is fastened in an annular fastening groove provided on the front inner surface.

[0114] according to Figure 8 In the embodiment shown, the third handle portion 14.3 is generally cylindrical and has a third outer diameter that is substantially the same as the first outer diameter of the first handle portion 14.1, and the front inner surface has an inner diameter that is substantially the same as the inner diameter of the first inner surface.

[0115] The hydraulic rotary impact hammer drill 2 further includes an additional leakage passage 45 defined between the shank 14 and the injection body 21 and extending from the front main sealing gasket 26 to the front spare sealing gasket 44. When an injection fluid leak occurs at the front main sealing gasket 26, the leaking flow will flow in the leakage passage 45.

[0116] according to Figure 8 In the illustrated embodiment, the additional leakage passage 45 has a varying cross-section between the front primary sealing gasket 26 and the front spare sealing gasket 44, and specifically includes an additional discharge chamber 46, which is annular and extends around the handle 14. The additional discharge chamber 46 is axially located between the front primary sealing gasket 26 and the front spare sealing gasket 44. Advantageously, the injection body 21 includes an additional annular discharge groove 47 that leads to the longitudinal passage 22 and partially defines the additional discharge chamber 46.

[0117] The hydraulic rotary impact hammer drill 2 also includes one or more additional fluid discharge ports 48, which are disposed on the injection body 21 and, for example, open radially to an additional discharge chamber 46. The additional fluid discharge ports, or each additional fluid discharge port 48, are configured to discharge leakage flow flowing in the additional leakage passage 45 outside the hydraulic rotary impact hammer drill 2.

[0118] according to Figure 8 In the illustrated embodiment, the injection body 21 includes a pressurization channel 49 that extends over at least a portion of the body length and extends substantially radially toward the front inner surface. A pressurization fluid (typically compressible and ideally lubricating) is supplied to this pressurization channel 49, thereby allowing for the limitation of rotational and translational friction between the handle 14 and the injection body 21.

[0119] Figure 9 A hydraulic rotary impact hammer drill 2 according to an eighth embodiment of the present invention is shown, which differs from the seventh embodiment mainly 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, wherein the inner diameter of the front inner surface is smaller than the inner diameter of the first inner surface, and the hydraulic rotary impact hammer drill 2 includes an additional pressure drop generating device disposed in an additional leakage passage 45 and configured to generate a pressure drop in the additional leakage passage 45 when a leakage flow flows in the additional leakage passage 45.

[0120] according to Figure 9 In the illustrated embodiment, the pressure drop generating device includes an additional deflection surface 51, which is annular and disposed on the injection body 21. The additional deflection surface 51 connects the front inner surface to the first inner surface.

[0121] according to Figure 9 In the illustrated embodiment, the additional deflecting surface 51 extends substantially perpendicular to the longitudinal axis of the handle 14 and is configured to redirect the leakage flow in the additional leakage passage 45 toward the front spare sealing gasket 44 from a flow direction substantially parallel to the longitudinal axis of the handle 14 to a flow direction perpendicular to the longitudinal axis of the handle 14. Advantageously, the additional deflecting surface 51 is configured to redirect the leakage flow toward the longitudinal axis of the handle 14.

[0122] According to a variation of the invention, the additional deflecting surface 51 may have a generally truncated conical shape and converge in the direction of the front spare sealing gasket 44. For example, the additional deflecting surface 51 is inclined at a certain angle relative to the longitudinal axis of the handle 14, the angle of inclination being between 1° and 89°, for example between 30° and 60°, advantageously about 45°.

[0123] Therefore, in the event of leakage in the front main sealing gasket 26 and the injection fluid being high-pressure water, the water jet originating from the front main sealing gasket 26 will be deflected at least once by the additional deflecting surface 51 provided on the injection body 21, and a second time by the outer surface of the third shank portion 14.3, before being loaded onto the front backup sealing gasket 44. These pressure drops will significantly limit the flow velocity of the water jet and thus reduce the dynamic pressure applied to the front backup sealing gasket 44. Consequently, the injection fluid leaking through the front main sealing gasket 26 can be discharged through the additional fluid discharge orifice 48 without directly loading the front backup sealing gasket 44, thereby significantly extending its service life.

[0124] Furthermore, given the significant reduction in dynamic pressure applied to the front spare sealing gasket 44 by the injected fluid, the predominant boosting pressure at the front of the front spare sealing gasket 44, due to the presence of the boosting channel 49, will be sufficient to limit the risk of leaking fluid infiltration caused by the boosting area of ​​the hydraulic rotary impact hammer drill or the boosting channel in the hydraulic area. Therefore, the presence of the additional deflection surface 51 allows for further increases in the reliability of the hydraulic rotary impact hammer drill 2 according to the invention.

[0125] According to another variation of the invention, the additional deflecting surface 51 may converge in the direction of the front primary sealing gasket 26 and is configured to guide leakage flow flowing in the additional leakage passage 45 along the direction of the front spare sealing gasket 44 towards the front primary sealing gasket 26. According to this embodiment of the invention, the additional deflecting surface 51 is inclined relative to the longitudinal axis of the shank 14 at a certain angle, which includes between 91° and 179°, for example between 120° and 150°, advantageously about 135°.

[0126] According to a variation of the invention, the injection body 21 may include a rear intermediate portion axially located between the rear primary sealing gasket 27 and the rear spare sealing gasket 28, and this rear intermediate portion will include an inner circumferential surface with a certain 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 in the leakage passage 29. According to this variation of the invention, the pressure drop generating device will be formed by the surface roughness of the deflection surface 34 and the inner circumferential surface.

[0127] According to another embodiment of the invention, in addition to the deflecting surface 34, the handle 14 may include a connecting portion located axially between the first handle portion and the second handle portion, the connecting portion including an outer peripheral surface having a certain surface roughness configured to generate a pressure drop in the leakage path (in addition to the pressure drop generated by the deflecting surface 34) when the leakage flow flows in the leakage path. According to this variation of the invention, the pressure drop generating device will be formed by the surface roughness of the deflecting surface 34 and the outer peripheral surface.

[0128] It goes without saying that the present invention is not limited to the only embodiment of the hydraulic rotary impact hammer drill described above as an example; rather, the present invention covers all its variations.

Claims

1. A hydraulic rotary impact hammer drill (2), comprising: -hammer drill body (3), - A fluid injection section (19) is provided on the front part of the hammer drill body (3). The fluid injection section (19) includes a longitudinal passage (22), a fluid feed inlet (23) for fluid connection with the injection fluid source, and an annular groove (25) fluidly connected to the fluid feed inlet and leading to the longitudinal passage (22). - A shank (14) for connection with at least one drill pipe equipped with a tool, the shank (14) having a longitudinal axis and extending in a longitudinal passage (22) of the fluid injection portion (19), the annular groove (25) extending around the shank (14), the shank (14) including 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 groove (25) and the fluid injection conduit (17). - Impact piston (5), which is slidably mounted inside the hammer drill body (3) along the impact axis (A) and is configured to strike the shank (14). - A front main sealing washer (26) and a rear main sealing washer (27), which are annular and each extends around the handle (14). The front main sealing washer (26) and the rear main sealing washer (27) are fastened to the fluid injection portion (19) and are axially disposed on both sides of the annular inner groove (25). The front main sealing washer (26) and the rear main sealing washer (27) are configured to fit tightly with the first handle portion (14.1) of the handle (14). - A rear spare sealing gasket (28), which is annular and extends around the handle (14), the rear spare sealing gasket (28) is located at the rear of the rear main sealing gasket (27) and is fastened to the fluid injection portion (19), the rear spare sealing gasket (28) is configured to fit tightly with the second handle portion (14.2) of the handle (14), - A leakage path (29), defined between the handle (14) and the fluid injection portion (19) and extending from the rear main sealing gasket (27) to the rear spare sealing gasket (28), wherein when a leak of injected fluid occurs at the rear main sealing gasket (27), the leaking flow will flow in the leakage path (29). - At least one fluid discharge port (33) is disposed on the fluid injection portion (19) and is fluidly connected to the leakage passage (29), the at least one fluid discharge port (33) being configured to discharge leakage flow flowing in the leakage passage (29) outside the hydraulic rotary impact hammer drill (2), The first shank portion (14.1) is cylindrical and has a first outer diameter, and the second shank portion (14.2) is cylindrical and has a second outer diameter that is significantly larger than the first outer diameter. The hydraulic rotary impact hammer drill (2) includes a pressure drop generating device disposed in the leakage passage (29) and configured to generate a pressure drop in the leakage passage (29) when a leakage flow flows in the leakage passage (29). The pressure drop generating device includes a deflection surface (34) disposed on the shank (14) and located between the first shank portion (14.1) and the second shank portion (14.2). The deflection surface (34) is configured to redirect the leakage flow flowing in the leakage passage (29) toward the rear spare sealing gasket (28) to a flow direction transverse to the longitudinal axis of the shank (14).

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

3. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The deflection surface (34) is configured to deflect the leakage flow in the leakage passage (29) toward the rear spare sealing gasket (28) such that the leakage flow deviates from the longitudinal axis of the handle (14).

4. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The deflection surface (34) is annular.

5. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The deflection surface (34) extends transversely to the longitudinal axis of the handle (14).

6. The hydraulic rotary impact hammer drill (2) according to claim 5, wherein, The deflecting surface (34) is tilted relative to the longitudinal axis of the handle (14) at an angle between 1° and 89°.

7. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The handle (14) includes a deflection collar (41) disposed on the outer surface of the handle (14) and including the deflection surface (34).

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

9. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The leakage path (29) includes a discharge chamber (31) that extends at least partially around the handle (14) and is located between the rear main sealing gasket (27) and the rear spare sealing gasket (28), and the at least one fluid discharge port (33) leads to the discharge chamber (31).

10. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The handle (14) includes a connecting portion located axially between the first handle portion and the second handle portion (14.1, 14.2), the connecting portion including an outer peripheral surface having a surface roughness configured to generate a pressure drop in the leakage passage (29) when a leakage flow flows in the leakage passage (29), the pressure drop generating device being formed at least in part by the surface roughness of the outer peripheral surface.

11. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, wherein, The fluid injection portion (19) includes a rear intermediate portion located axially between the rear main sealing gasket (27) and the rear spare sealing gasket (28). 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 a leakage flow flows in the leakage passage (29). The pressure drop generating device is formed at least in part by the surface roughness of the inner circumferential surface.

12. The hydraulic rotary impact hammer drill (2) according to claim 1 or 2, further comprising: - A front spare sealing gasket (44), which is annular and extends around the handle (14), is located at the front of the front main sealing gasket (26) and is fastened to the fluid injection portion (19), and is configured to fit tightly with the third handle portion (14.3) of the handle (14). - An additional leakage path (45), defined between the handle (14) and the fluid injection portion (19) and extending from the front main sealing gasket (26) to the front spare sealing gasket (44), in the event of a leak of injected fluid at the front main sealing gasket (26), the leaking flow will flow in the additional leakage path (45). - At least one additional fluid discharge port (48) is disposed on the fluid injection portion (19) and fluidly connected to the additional leakage passage (45), the at least one additional fluid discharge port (48) being configured to discharge leakage flow flowing in the additional leakage passage (45) outside the hydraulic rotary impact hammer drill (2), - An additional pressure drop generating device is disposed in the additional leakage passage (45) and configured to generate a pressure drop in the additional leakage passage (45) when a leakage flow flows in the additional leakage passage (45).

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

14. The hydraulic rotary impact hammer drill (2) according to claim 13, wherein, The additional pressure drop generating device includes an additional deflection surface (51) disposed on the fluid injection portion (19) and located between the first handle portion (14.1) and the third handle portion (14.3). The additional deflection surface (51) is configured to redirect leakage flow in the additional leakage passage (45) toward the front spare sealing gasket (44) in a flow direction transverse to the longitudinal axis of the handle (14).

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