Method for drilling components to be assembled and drilling tool

Description

TECHNICAL FIELD

[0001] The invention relates to a method for drilling structural parts (panels, partitions, sections, etc.) arranged in the assembly position, and to a sealed drilling tool for removing all the chips produced during drilling without polluting the working environment. Any type of installation comprising assembled structures is intended to be able to follow this method and use this sealed drilling tool, in particular vehicles such as aircraft, trains, ships, and construction buildings. The invention also applies to the drilling of a single structural part to be fixed to a support or to be assembled to any equipment.

[0002] Thus, in the aeronautical field, every aircraft is made up of structures assembled to form its architecture. The assembly of these structures is based on so-called "classic" methods in which the structures are first drilled before the installation of fasteners, and this drilling step produces a large quantity of machining chips which must then be removed to clean the structures.

[0003] Some of these structures, such as doors, are located in areas that are difficult to access due to their complex shape and small size: specific drilling techniques then rely on machines capable of coming into contact with each face of the material to be drilled. STATE OF THE ART

[0004] Traditionally, when assembling structural parts, particularly in the aeronautical field, they are first mounted once and then held in the assembly position using pins during a preliminary pinning step before being drilled. This drilling passes through the parts and then produces numerous machining chips which spread in the vicinity of the drilled bore. This environment must then be cleaned and this cleaning requires a complete disassembly of the assembly because the parts are then subjected to a surface treatment. The main purpose of this treatment is to smooth the surface of the parts and therefore also produces residues which must also be cleaned. Conventionally, interposition putty is applied to the interface of the parts to be assembled, in order to avoid any free space between the parts, before reassembling them and carrying out a second positioning pinning.The last step is the assembly of the parts, generally by riveting.

[0005] Drilling of aeronautical structures is therefore carried out during the first stages of assembly of these structures and at least two cleaning stages are necessary to remove the shavings produced during assembly. In addition, the interposition putty used must be applied to clean interfaces because it cannot be contaminated by residues under penalty of having to be replaced.

[0006] These successive cleanings represent meticulous tasks that are time-consuming and cannot be avoided due to the production of chips and waste during machining.

[0007] Another problem related to this type of installation is the repetition of successive assembly-disassembly-reassembly of the structures to be assembled: each assembly is accompanied by pinning in order to position the structural parts. In addition to the time required to carry out these steps, reassembly can present problems for assembly: since the drilling is carried out during the first assembly, disassembly and reassembly do not guarantee that the drilled holes are again correctly aligned opposite each other, which would result in quality problems, leading to additional machining and cleaning.

[0008] In order to recover shavings, document US2021069844 A1 discloses a drill equipped with an adjustable suction chamber around the drill bit, this chamber coming into contact with the surface to be drilled to partition the drilling space. However, such a suction chamber is bulky and is therefore not suitable for drilling holes in confined areas.

[0009] Furthermore, document EP0832722A1, which discloses a drilling method according to the preamble of claim 1 and a drilling tool according to the preamble of claim 7, illustrates a “C-clamp” type drilling machine whose clamp allows it to grip the structures to be assembled and carry out drilling in areas of limited accessibility. However, this tool does not allow the removal of chips which spread in the vicinity of the drilled hole, thus requiring disassembly to carry out cleaning.

[0010] To solve accessibility problems, a commonly used drill is arranged in one of the branches of a clamp coming from either side of the structural elements to be drilled. This type of drill has a blower as well as a suction system via flutes on the drill bit for chip evacuation. This chip evacuation is necessary to meet the high levels of drilling quality required, particularly in the aeronautical field, and to avoid unwanted widening of the bore due to the accumulation of chips in the bore.

[0011] However, chip suction is not complete: part of the chips is ejected at the entrance to the bore via radial grooves made on the machine nose, the front part of the drill in contact with the structure, the primary function of these grooves being to allow a chip suction flow. In addition, during unclogging, that is to say when the drilled hole becomes through, a sudden ejection of chips occurs at the exit of the bore through the second branch of the clamp, causing exit burrs and polluting the work area. The branch of the clamp at the exit of the bore is hollow and open to the outside for the evacuation of chips, the accumulation of which, even limited, can cause the drill bit to break, problems with precision, time and drilling quality. STATEMENT OF THE INVENTION

[0012] In order to overcome the disadvantages of the prior art set out above, the main objective of the invention is to recover and control the evacuation of all the chips generated during drilling, before they spread into the environment around the bore formed, thus making it possible to avoid costly disassembly / reassembly steps of the structures to be assembled. The term "upstream" means "coming from the side where drilling begins" and "downstream" refers to the side where the bore opens out, each side being defined on either side of the part(s) to be drilled. In addition, "upstream blowing" describes blowing coming from upstream and directed downstream, while downstream blowing describes blowing in the opposite direction, i.e. directed from downstream to upstream.

[0013] To do this, the invention provides for implementing a method of drilling parts to be assembled and recovering chips using a drill mounted on a clamp branch, using downstream blowing and avoiding upstream radial ejection of chips in order to achieve sealed evacuation.

[0014] More specifically, the present invention relates to a method for drilling at least one bore in one or more parts positioned according to the claim. These parts are stacked and then clamped between upstream and downstream branches of a clamp of a drilling tool. The upstream branch accommodates a drill equipped with a drill bit and the downstream branch is hollow and open to the outside. A so-called upstream blow directed towards the parts to be assembled circulates air through the drill bit and then in the opposite direction in lateral flutes extending along this drill bit.

[0015] The drilling process is carried out in the following steps: positioning the clamp of the drilling tool on a drilling location of the part(s); selection and mounting of the drill corresponding to a diameter of the bore to be drilled, then positioning the drill in the activation position; triggering the upstream blowing of pressurized air; beginning the advance of the drill in the upstream direction and triggering a downstream blowing of pressurized air, the downstream blowing being carried out in a sealed environment in the hollow downstream branch of the clamp of the drilling tool and in the opposite direction to said upstream blowing; advancing the drill in the downstream direction in the parts by forming chips until the bore is cleared, extraction of the chips in the upstream direction via the flutes of the drill then evacuation of these chips in a sealed environment; withdrawal of the drill from the bore;maintaining the blows after unblocking and removing the drill from the bore, the downstream blow keeping the chips in the bore for complete suction, then stopping the blows, and uninstalling the clamp from the drilling tool.;

[0016] By unclogging is meant the state of drilling of the last part drilled at the moment when the bore becomes completely through or through, the diameter of the bore then being constant over its entire length.

[0017] Advantageously, the chips produced are all sucked up by the upstream clamp due to the tightness of their evacuation and do not become debris or residues which would spread, accumulate and insert themselves on the structural parts or other surfaces in the vicinity, unlike the conventional method. The combination of downstream blowing and upstream evacuation in a sealed environment according to the invention therefore makes it possible to avoid intermediate cleaning and disassembly / reassembly steps, which generates a substantial time saving during assembly. In addition, since the drilling is carried out before assembly, without an intermediate disassembly / reassembly step, the bores of each part to be assembled are therefore directly and correctly aligned without the need to adjust the positioning of each of these parts, which also promotes rapid and precise assembly of the whole.

[0018] In certain preferred forms of implementation: the evacuation of the chips is carried out by suction; in the case where the parts are intended to be assembled, they are previously pinned after stacking and assembled after drilling; the downstream blowing of pressurized air is triggered before the start of the advance of the drill; following the removal of the drill from the bore, the drill can be changed for another of larger diameter to increase the diameter of the bore; after uninstalling the clamp from the drilling tool, it can be moved and put in place in different locations to proceed with the drilling of other bores and the assembly of the structural parts at different points.

[0019] Advantageously, triggering the downstream blowing before the drill begins to advance saves time and makes it easier to carry out, as the drill advances to the unblocking point are generally carried out in a single step. Indeed, since the purpose of downstream blowing is to prevent chips from being ejected into the downstream branch during unblocking, this prior triggering of the downstream blowing pushes any chips or other residue into the upstream branch via the drill flutes.

[0020] Advantageously also, the drilling process can be repeated either by changing the drill bit to enlarge the bore, or by moving the sealed drilling clamp to make a new bore. Changing the drill bit after removing the drill while keeping the sealed drilling clamp in position improves the accuracy when drilling a large diameter bore requiring drilling a first bore called a pilot hole which is then enlarged when using a larger diameter drill bit.

[0021] The invention also relates to a tool for drilling at least one structural part according to claim 7, comprising the drill equipped with the drill bit provided with the lateral chip extraction flutes and the upstream blowing means of pressurized air through a central axis of the drill bit. The tool further comprises the clamp with two branches which grip the part(s) by an open end on each of the branches. The downstream branch receives in a sealed manner by its open end a downstream blowing member of pressurized air in the opposite direction and with a working pressure at least equal to that of the upstream blowing in order to push back the chips when the bore is open. The drilling tool is also provided with a sealed chip evacuation and recovery member cooperating with the lateral extraction flutes and a sealed machine nose arranged at the open end of the upstream branch and in contact with the structural part to be drilled.

[0022] Advantageously, the combination of the sealed machine nose and the downstream air blowing thus hermetically closes the drilling zone and the chips therefore have as their only exit route extraction through the lateral flutes of the drill and then through the evacuation member. In addition, the air blowing in the downstream branch pushes the flow of chips towards the upstream branch of the clamp and towards the suction and evacuation-recovery zone during unclogging. Contamination of the structural part(s) by chips is thus completely avoided, in particular that of the interposition putty. Since the cleaning steps and consequently those of disassembly / reassembly are no longer necessary, a gain in productivity is generated.

[0023] According to certain preferred embodiments: to achieve sealing, the rigidity of the machine nose is less than that of the structural part(s) to be drilled in order to fit its shape passively and / or a clamping mechanism holds it on the structural part(s) chosen from a hydraulic, pneumatic and electrical system; the air for the upstream and downstream blows comes from the same compressed air network, in particular at least 6 bars; in the case where the evacuation is carried out by suction, a depression of at least 0.1 bar is established in the evacuation member; the air blow may contain a lubricant which is evacuated in the same way as the chips, and the clamp may be chosen from a C-Clamp type clamp, a J-Clamp type clamp and a spring clamp. PRESENTATION OF FIGURES

[0024] Other characteristics and advantages of the present invention will emerge from the following reading of a detailed example of embodiment without limiting its scope, with reference to the appended figures which represent, respectively: there figure 1 , a cutaway perspective view of two structural pieces being assembled; the figure 2 , a sectional view of the walls of the parts to be drilled along a plane perpendicular to the walls, when the drilling tool is in place; figure 3 , the sectional view according to the figure 2 at the start of drilling; the figure 4 , the sectional view according to the figure 2 being drilled; the figure 5 , the sectional view according to the figure 2 when the piercing is about to become clear; figure 6 , the sectional view according to the figure 2 when the drilling is through; the figure 7 , the sectional view according to the figure 2 at the end of the drilling; the figure 8 , the same detailed sectional view of the bore which has become open, and the figure 9 , an example of a flowchart detailing the steps of the process. DETAILED DESCRIPTION

[0025] There figure 1 represents a perspective view cut along plane P1 of two metal parts during their assembly, composed of an upstream part 1a and a downstream part 1b, “upstream” and “downstream” distinguishing the first part to be pierced (upstream) from the second (downstream). These parts 1a, 1b correspond in the example to portions of adjacent sections of fuselage of an aircraft to be riveted. They each have a flat wall 10a and 10b, these walls being positioned against each other to be mounted by stacking and pinning.

[0026] Then the walls 10a, 10b are drilled according to the method of the invention to produce, in this example, two drill holes 8 and 8'. The drill hole 8' (seen in section) is used, in the illustrated example, to crimp a rivet 7 for assembling the two walls 10a and 10b. An embodiment of a drilling tool 100 used to drill two wall structure parts 10a and 10b is detailed in the following figures.

[0027] The sectional view of the figure 2 according to plan P1 of the figure 1 , perpendicular to the walls 10a and 10b, shows more precisely the constituent elements of the drilling tool 100 as well as its positioning on the desired location in order to carry out the drilling (the final result of which appears in figure 1 ). The tool is built around a C-clamp type clamp 2 for sealed drilling according to the example illustrated, composed of an upstream branch 2a and a downstream branch 2b. These two branches are integral and grip the upstream 1a and downstream 1b parts to be assembled, more precisely the upstream 10a and downstream 10b walls, by the support 2h and the machine nose 2k. Interposition putty 1c was coated at the junction between the upstream 1a and downstream 1b parts in order to fill the machining defects of the parts and to join them.

[0028] The downstream branch 2b is fixed and has at its end 2d a downstream hollow pipe 2e forming an open end and having two end terminals 2f and 2g. The support 2h establishes at the terminal 2f a sealed contact with the assembly wall 10b of the downstream part 1b and the other opening terminal 2g of the downstream hollow pipe 2e receives in a sealed manner in the direction 9b a downstream air blowing member 2i. This pipe 2i brings a flow of pressurized air into the downstream hollow pipe 2e.

[0029] The upstream branch 2a comprises an upstream hollow conduit 2j sliding in the direction 9a forming an open end parallel to the direction 9b, to engage the machine nose 2k arranged at this open end of the upstream branch 2a and in contact with the wall 10a of the upstream part 1a of the structure to be drilled. This machine nose 2k is made of a material of lower rigidity than that of the part 1a and maintains the sealing of the contact passively. The upstream hollow conduit 2j houses on the one hand the drill 3 in its cavity and on the other hand an evacuation path 4 fitted into its periphery constituting a sealed evacuation and recovery member cooperating with the lateral extraction flutes 3b and the sealed machine nose 2k.

[0030] The drill 3, equipped with a drill bit 3a, is movable in the direction 9c, allowing, when the upstream hollow pipe 2j is in contact with the wall 10a of the upstream part 1a, the drill bit 3a to advance to carry out the drilling through the walls 10a and 10b, respectively of the upstream 1a and downstream 1b parts. This drill 3a is provided with lateral chip extraction flutes 3b winding helically along the drill 3a which, combined with the upstream pressurized air blowing 5a through the central axis 30a of the drill 3a, extract the chips 6 formed during drilling by raising them so that they are evacuated by suction in the evacuation path 4. The pressurized air of the upstream blowing 5a coming from a compressor (not shown) is directed according to the arrow F1 through a central axis 30 of the drill 3 aligned with the central axis 30a of the drill 3a, up to the end 31a of the conical drill tip 32a.This upstream blowing air 5a can optionally contain a lubricant which is subsequently sucked in and evacuated at the same time as the chips.

[0031] The sectional view of the figure 3 illustrates the installation of the drilling tool 100: the upstream 2a and downstream 2b branches then hold the walls 10a and 10b of the upstream 1a and downstream 1b parts in a sealed manner, and the drill 3a arrives close to the upstream wall 1a to begin drilling. The upstream blower 5a is triggered and propelled into the axis 30a of the drill 3a air at 6 bars. The air suction (arrow 5c) is advantageously reinforced by a depression of 0.5 bar created at a distant end (not shown). Other depression values can be used, for example between 0.1 bar and 1 bar.

[0032] The downstream blow pipe 2i is installed in the downstream hollow pipe 2e, allowing this pipe to be completely sealed. In this embodiment, the downstream blow (arrows 5b) is triggered at the start of drilling and the downstream blow pipe 2i is connected to the same compressed air network as the upstream blow 5a, and therefore propels compressed air also at 6 bars in this example. The downstream blow (arrows 5b) can also be triggered later after the start of drilling and before it becomes a through hole, i.e. before the drill 3a completely passes through the two upstream 1a and downstream 1b walls. Drilling is then carried out in two stages: a first stage before clearing and then a second stage from the moment of clearing. However, it is advantageous to trigger the downstream blowing (arrows 5b) before starting drilling so as to merge the two stages into a single stage.

[0033] The sectional view of the figure 4 documents the start of drilling: drill 3a digs hole 8 in upstream wall 1a and chips 6, carried by the air from upstream blowing 5a are extracted from hole 8 following lateral flutes 3b, then sucked into discharge path 4. In fact, the air from upstream blowing 5a produces suction in the opposite direction to upstream blowing 5a via the flutes along the drill bit before being sucked into discharge path 4 by the depression (arrows 5c) created in this path. Upstream blowing 5a and downstream blowing 5b are maintained under 6 bars throughout drilling.

[0034] In the sectional view of the figure 5 , the drilling is almost opening onto the downstream face 12b of the wall 10b of the downstream part 1b, and there remains only a thin layer of material in the hole 8 before the drill 3a is opening onto this face 12b. If the downstream blowing 5b has not been triggered at the start of drilling, the progression of the drill 3a is stopped to avoid expulsion of the chips 6 into the downstream hollow pipe 2e under the action of the upstream blowing 5a during unblocking.

[0035] The unclogging is illustrated in the detailed sectional view of the Figure 8 : the drill 3a has started to perforate the downstream face 12b of the downstream wall 10b and only tabs 8a remain in the hole 8 drilled in the form of a bore 8b in the downstream wall 10b. The chips 6 are held in the bore 8b by the pressure of the downstream blower 5b which is equal to the pressure of the upstream blower 5a, thus allowing the extraction (arrows 5d) of the chips by the flutes 3b before being sucked up for evacuation (arrows 5c, cf. figures 4 And 5 ).

[0036] In this embodiment, the air from the upstream blowing 5a and the air from the downstream blowing 5b come from the same compressed air network by a common compressor and are therefore at the same pressure: it is however possible to use for the downstream blowing 5b a pressure higher than that of the upstream blowing 5a. In all cases, the working pressure of the downstream blowing is in the opposite direction and at least equal to that of the upstream blowing to be able to push any chips or part of chips downstream of the face 12b into the bore 8b when the bore is open and therefore create a “virtual” sealed bottom for chips and their derivatives: these residues can therefore only leave the bore 8b through the flutes 3b before being sucked in.

[0037] In the sectional view of the figure 6 , the drill 3a is entirely through and the last chips 6 are evacuated in the suction path 4. The upstream 5a and downstream 5b blows, as well as the suction 5c are maintained to suck up all the chips from the drilling until the withdrawal of the drill 3a which returns to its initial position by displacement parallel to the direction 9c, as illustrated in the figure 7 . The upstream hollow pipe 2j is then moved in the direction 9a, parallel to the direction 9c, to release the upstream 1a and downstream 1b structural parts from the C-clamp 2. This clamp 2 can then be positioned in different locations to drill other bores. The drill bit 3a can also be exchanged with another one of larger diameter in order to drill a larger diameter or to gradually enlarge the diameter of a previously drilled bore.

[0038] There figure 9shows the flowchart of the method for drilling a bore 8b in two structural parts 1a and 1b positioned against each other for assembly: these parts 1a and 1b are stacked then pinned and clamped between the upstream 2a and downstream 2b branches of the clamp 2 of a drilling tool 100. The upstream branch 2a accommodates a drill 3 equipped with a drill bit 3a and the downstream branch 2b is hollow and open to the outside at its end 2d. The upstream blower 5a, directed towards the parts 1a and 1b to be assembled, circulates air through the drill bit 3a then in the opposite direction in the flutes extending along the drill bit 3a.

[0039] The drilling process begins with the positioning of the clamp 2 of the drilling tool 100 on the desired drilling location (step 201) of the parts 1a and 1b, by the selection and mounting of the drill 3a corresponding to the diameter of the bore 8b to be drilled (step 202), as well as the positioning of the drill 3a in the activation position (step 203).

[0040] After the drilling tool 100 has been put in place, the operator triggers the upstream air flows (step 204), namely the upstream blowing 5a of pressurized air and the suction 5c, before proceeding in this exemplary embodiment to trigger the downstream blowing 5b of pressurized air (step 205a) then to the start of the advancement of the drill 3 (step 205b) thus making it possible to suck up the chips 6 resulting from the drilling. The downstream blowing 5b is carried out in a sealed environment at the hollow end 2e of the downstream branch 2b of the clamp 2 of the drilling tool 100 and in the opposite direction to said upstream blowing 5a. In other embodiments, steps 205a and 205b can be reversed, the downstream blowing 5b being triggered before the drilling is through (step 206).

[0041] The drill 3 advances in the downstream direction in the parts 1a and 1b, forming chips 6 until the bore 8b is unblocked. These chips 6 are extracted upstream via the flutes 3b of the drill 3a and are then evacuated into a sealed environment. The blowing and suction are maintained (step 208) after the unblocking and removal of the drill from the bore 8b (step 207) in order to achieve complete evacuation of the chips by suction. Then the blowing and suction are stopped: the operator can then proceed to uninstall the clamp (step 209) and thus complete the drilling with an assembly of the structural parts 1a and 1b by riveting (step 210).

[0042] According to certain forms of implementation, following step 208, the drill 3a can be changed for another of larger diameter (step 211) then the drill 3a is again placed in the activation position (step 203) to increase the diameter of the bore 8b.

[0043] After uninstalling the clamp 2 from the drilling tool 100 (step 209), it can be moved (step 212) and placed in different locations (step 201) to drill other bores and then assemble the structural parts 1a and 1b at different points 8 and 8'.

[0044] The invention is not limited to the examples described and shown.

[0045] Thus, the materials of the structural parts used can be chosen between metallic materials, composite materials, wood, plastic and a combination of metallic, composite, wood and plastic material. In addition, the 2k machine nose, which maintains the seal passively, can be replaced by active systems also allowing this maintenance by a clamping mechanism attached to the downstream branch of the clamp, such as a hydraulic, pneumatic or electric system. In the case of composite materials containing carbon, the carbon dust resulting from drilling is carried away by the sealed chip evacuation, without contaminating the operator's environment.

[0046] Furthermore, the tool and the process are suitable for drilling two structural parts but are also suitable for drilling a single part in order to fix it later, for example on equipment. Generally, the assembly of the part(s) is carried out by riveting, by a screw-nut assembly or by any other means (staples, pins, spacers, etc.).

[0047] Also, types of clamps other than C-clamp type are suitable for clamping the upstream 1a and downstream 1b parts, such as J-clamp type clamps, spring clamps, hydraulic clamps, cylinder clamps. In particular, the upstream branch of the clamp can be constituted for its main element by the drill surrounded by a waterproof structure.

[0048] Finally, the downstream blowing can be triggered at any time, in particular during the advancement of the drill or after unblocking provided that the downstream blowing 5b and the suction 5c are maintained for a sufficiently long time after the withdrawal of the drill 3a. The suction 5c used by this embodiment example is optional: the sealing of the tool combined with the blowing and the evacuation member 4 allows a natural exit of the drilling chips.

Claims

1. Method for drilling at least one bore (8b) in one or more positioned structural parts (1a, 1b), these parts being stacked then clamped between an upstream branch (2a) and a downstream branch (2b) of a clamp (2) of a drilling tool (100), the upstream branch (2a) receiving a drilling machine (3) equipped with a drill bit (3a) and the downstream branch (2b) being hollow and open to the outside, the drilling taking place according to the following steps: - positioning the clamp (2) of the drilling tool (100) on a drilling location of the parts (1a, 1b); - selection and assembly of the drill bit (3a) corresponding to a diameter of the bore (8b) to be drilled then positioning of the drill bit (3a) in the activation position; characterized in that a so-called upstream blowing directed towards the parts (1a, 1b) to be assembled circulates air through the drill bit (3a) then in the opposite direction in lateral grooves (3b) extending along this drill bit (3a), and in that the drilling also takes place according to the following steps: - triggering of the upstream blowing (5a) of pressurized air; - start of the advance of the drilling machine (3) and triggering of the downstream blowing (5b) of pressurized air, the downstream blowing (5b) being carried out in an airtight environment in the hollow downstream branch (2b) of the clamp (2) of the drilling tool (100) and in the opposite direction to said upstream blowing (5a); - advancement of the drilling machine (3) in the downstream direction in the parts (1a, 1b) until the bore (8b) is cleared, extraction of the chips (6) in the upstream direction via the grooves (3b) of the drill bit (3) then evacuation of these chips (6) in an airtight environment; - removal of the drill bit (3a) from the bore (8b); - maintaining the blowings (5a, 5b) after unblocking and removing the drill bit (3a) from the bore (8b), then stopping the blowings; and - uninstallation of the clamp (2) from the airtight drilling tool (100).

2. Drilling method according to claim 1, wherein the evacuation of the chips (6) is carried out by suction (5c).

3. Drilling method according to any one of the preceding claims, wherein the parts (1a, 1b) are previously pinned after stacking and assembled after drilling.

4. Drilling method according to any one of the preceding claims, wherein the downstream blowing (5b) of pressurized air is triggered before the start of the advance of the drill (3).

5. Drilling method according to any preceding claim wherein following removal of the drill bit (3a) from the bore (8a), the drill bit (3a) is changed to one of larger diameter.

6. Drilling method according to any one of the preceding claims, wherein following the uninstallation of the clamp (2) from the drilling tool (100), the latter is moved and placed in different locations.

7. Drilling tool (100) for implementing the method according to any one of the preceding claims, of at least one structural part (1a, 1b) comprising the drilling machine (3) equipped with the drill bit (3a) provided with the lateral grooves (3b) for extracting chips (6), further comprising the clamp (2) with two branches (2a, 2b) gripping the part(s) (1a, 1b) by an open end on each of the branches (2a, 2b), characterized in that the drilling machine (3) comprises the upstream blowing (5a) means of pressurized air through a central axis (30a) of the drill bit (3a) and in that the downstream branch (2b) receives in an airtight manner by its open end (2e) a downstream blowing (5b) member of pressurized air in the opposite direction and with a working pressure at least equal to that of the upstream blowing (5a) and in that the drilling tool (100) is equipped with an airtight chip (6) evacuation and recovery member cooperating with the lateral extraction grooves (3b) and an airtight machine nose (2k) arranged at the open end of the upstream branch (2a) and in contact with the structural part (1a) to be drilled.

8. Drilling tool according to the preceding claim wherein the rigidity of the machine nose (2k) is less than that of the structural part(s) (1a, 1b) to be drilled and / or a clamping mechanism holds it on the structural part(s) (1a, 1b) chosen from a hydraulic, pneumatic and electric system.

9. Drilling tool according to any one of claims 7 and 8, wherein the air from the upstream blowing (5a) and downstream blowing (5b) comes from the same compressed air network.

10. A drilling tool according to any one of claims 7 to 9, wherein a depression of at least 0.1 bar is established in the evacuation device (4).

11. A drilling tool according to any one of claims 7 to 10, wherein the air blowing contains lubricant.

12. A drilling tool according to any one of claims 7 to 11, wherein the clamp (2) is selected from a C-Clamp type clamp, a J-Clamp type clamp and a spring clamp.