Drilling device particularly usable in an aeronautical machining process

Abstract

Drilling device comprising: an external support element (2); a central tubular element (3) carried by the external support element (2) and sliding with respect to the external support element (2) along an axis (H) with opposite directions; the central tubular element (3) being provided at a first end (3-a) with three abutment teeth (5) and having a second end (3-b) configured to house in a radially fixed manner a portion (7) of a drilling head (8) provided with a drilling tool (9). The drilling device further comprises a suction cup element (12) with an annular end portion (13) that externally surrounds the end edge (4), wherein, in use, the suction cup element (12) is firmly connected to the surface (15) and the central tubular element (3) can be made to advance axially by applying a thrust to the tubular element (3) by means of the drilling head (8).

Description

[0001] "DRILLING DEVICE PARTICULARLY USABLE IN AN AERONAUTICAL MACHINING PROCESS"

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No . 102023000027714 filed on December 21 , 2023 , the entire disclosure of which is incorporated herein by reference .

[0004] Field of the Art

[0005] The present invention relates to a drilling device particularly usable in an aeronautical machining process .

[0006] Background of the Invention

[0007] In aeronautical machining processes , there are currently various drilling methods , among which the following are listed .

[0008] Manual drilling by using a drilling device carried by an operator .

[0009] This drilling method is normally used in the aeronautical field to carry out repairs , for example on components already assembled and j oined by installing fixed connecting elements . The operation is performed by centring the drilling device ( for example , a drill ) on the previously installed fixed connecting element and by pushing manually by the operator on the drilling device , it allows the connecting element to be removed .

[0010] Although this method is easy to use and does not require j igs or support systems , there are a number of disadvantages , comprising :

[0011] - uncontrollability of the drilling depth; risk of damaging the surface of the component and the existing hole ( ovali zation or notching of the inner diameter ) ;

[0012] - long working times , compared to an automatic method; quality of the workmanship extremely dependent on the experience of the operator ;

[0013] - tiring working conditions for the operator ; and the method does not guarantee the repeatability of the operation .

[0014] Manual drilling by using a drilling device arranged on a tripod .

[0015] This method in the aeronautical field is normally used to perform coupling drilling between components during the manufacturing of an aeronautical structural assembly . The connection member must be integrated to the end of the drilling device ( for example , a drill ) . The tripod, by means of its three support points , forms a medium plane in the area adj acent to the hole , thus orienting the drilling device .

[0016] Although this method is easy to use , inexpensive and does not require j igs or support systems , there are a number of disadvantages comprising :

[0017] - risk of damaging the existing hole ;

[0018] - repeatability of the operation dependent on the experience of the operator ;

[0019] - tiring working conditions for the operator ;

[0020] - long working times , compared to an automatic system;

[0021] - the need to make a pre-hole ;

[0022] - the parts after drilling require deburring due to the burr formed during the drilling process (passage of the tool between one component and another ) ;

[0023] - processing that does not guarantee repeatability;

[0024] - risk of hole ovali zation .

[0025] Manual drilling by using drilling j igs .

[0026] This method in the aeronautical field is normally used to perform coupling drilling between components during the manufacturing of an aeronautical structural assembly and drilling j igs are generally arranged referring to appropriate locators on an assembly rig . Drilling j igs are components that are generally made of metal material provided with guide bushings whose function is to guide the drilling device .

[0027] Although this method is easy and inexpensive , assuring high repeatability and a better hole quality than that achieved by the above methods , there are a number of disadvantages comprising : presence of non-recurring costs due to the design and construction of the drilling j ig; the j igs cannot be used when the hole spacing has a dimension smaller than the sum of the diameters of the guide bushings ;

[0028] - wear of the contact elements ;

[0029] - long working times , compared to an automated system;

[0030] - the accuracy of perpendicularity of the hole relative to the plane depends on the j ig and not on the shape of the component to be drilled around the hole ;

[0031] - quality of the hole depends on the operator experience ;

[0032] - tiring for the operators ; and

[0033] - the parts after drilling need deburring due to burr formed during the drilling process (passage of the tool between one component and another ) .

[0034] Semi-automatic drilling by using drilling j igs and a system with automatic drilling device advancement .

[0035] This method in the aeronautical field is normally used to perform coupling drilling between components during the manufacturing of an aeronautical structural assembly and generally the j igs are arranged by referring to appropriate locators on an assembly rig . The drilling j igs are components generally made of metal material provided with bushings and attachments for the drilling system with advancement control along an axis " Z ( drilling axis ) " of a drilling device .

[0036] Although this method allows the repeatability of the process , allows the improvement of the hole quality, minimi zes the possibility of hole ovali zation and implements an improvement compared to drilling with manual j igs , there are a series of disadvantages comprising :

[0037] - non-recurring costs for the design and manufacturing of the drilling j ig;

[0038] - need for adequately proportioned j igs to support the weight of the drilling devices ;

[0039] - not usable when the hole spacing has a dimension smaller than the sum of the diameters of the guide bushings ;

[0040] - not usable on rigs not duly proportional to the weight of the j igs themselves ;

[0041] - maintenance of the interface areas of the j ig with the ass e mb 1 y rig;

[0042] - wear of the elements in contact ;

[0043] - limited use due to undercuts , structural impediments ;

[0044] - the parts after drilling require deburring due to the burr formed during the drilling process (passage of the tool between one component and another ) ; and di f ficulty in choosing the average tool advancement parameters in the di f ferent material packages to be drilled .

[0045] Drilling with CNC gantry machines

[0046] This method in the aeronautical field is used to perform coupling drilling between components during the manufacturing of an aeronautical structural assembly and generally the components arranged on an assembly rig are arranged inside the work area of the gantry machine . CNC processing machines have lightened heads that are appropriately si zed for the drilling process only .

[0047] The positive aspects of this method are :

[0048] - repeatability of the process ;

[0049] - controllable and repeatable production times ;

[0050] - high quality of the hole made ;

[0051] - random control of the drilling; - speed of work execution; signi ficant improvement compared to drilling with manual j igs ;

[0052] - control of drilling depth with narrow tolerances ;

[0053] - possibility of performing countersinking with very narrow tolerances .

[0054] However, the following disadvantages should be noted : large investments for the acquisition of the system and installation thereof ( construction works to support the load of the gantry system) ;

[0055] - very complex and expensive equipment ;

[0056] - limit of use in undercuts ;

[0057] - limit of drilling due to large dimensions of the drilling head; production l ines designed for the single product and therefore not easy to use on other products ; logistics within the production flow, controlled by the machine ( tack time ) ;

[0058] - need for highly experienced operators to program drilling paths ; and

[0059] - need for back-up solutions in the event that the machine stops for extraordinary maintenance or other reasons .

[0060] Drilling made by using anthropomorphic robots .

[0061] This method in the aeronautical field is used to perform coupling drilling between components during the manufacturing of an aeronautical structural assembly that takes place on a dedicated rig .

[0062] The drilling system is installed at the end of an anthropomorphic robot mounted on a fixed guide or on an AGV and in this case , unlike the CNC drilling machine , it is the robotic drilling system that moves towards the flight span .

[0063] The positive aspects of this method are : - repeatability of the process ;

[0064] - high quality of the hole made ;

[0065] - random control of the drilling;

[0066] - speed of work execution;

[0067] - control of drilling depth with narrow tolerances ;

[0068] - possibility of performing countersinking with very narrow tolerances ;

[0069] - controllable and repeatable production times ;

[0070] - possibility of drilling without re-burring with great time savings and reduced flows ; greater flexibility of the method compared to a gantry machine ;

[0071] - superior capacity compared to a gantry machine in drilling in narrow or undercut areas .

[0072] However, the following disadvantages should be noted :

[0073] - large investments for the acquisition of the system and the installation thereof ( construction work to support the load of the system) ;

[0074] - very complex equipment ;

[0075] - very expensive equipment ;

[0076] - limit of use in undercuts ;

[0077] - limit of drilling due to large dimensions of the drilling head; logistics within the production flow, constrained by the machine , a criticality that increases i f the drilling system is mounted on a robot that moves on a fixed guide ;

[0078] - the system must be managed by speciali zed operators ;

[0079] - need to provide back-up solutions in the event that the system stops due to extraordinary maintenance .

[0080] There is therefore a need to obtain an extremely simple drilling device that still allows ensuring a high drilling quality like that of gantry machines or CNC systems while having a reduced cost . The document US2020156161A1 describes a device for removing a fastener installed in the hole of an aircraft structure , which comprises : a base capable of being fixed to the structure by means of suction cups , and a guiding device , which defines a cylindrical passage and comprises : a support provided with a first removable mounting means with the base in a first assembled configuration; a locking element , movable relative to the support ; and a device for adj usting an axial position of the locking element relative to the support, in a locked configuration corresponding to the engagement of said locking element with the fastener, so as to prevent rotation of said fastener relative to the structure .

[0081] Object of the Invention

[0082] The foregoing obj ect is achieved by the present invention in that it relates to a drilling device of the type described in claim 1 .

[0083] Description of the Drawings

[0084] The invention will be illustrated with the attached figures which represent a preferred example of embodiment , wherein : Figure 1 represents a perspective view of a drilling device made according to the dictates of the present invention;

[0085] Figure 2 is a front perspective view of the drilling device according to the present invention;

[0086] Figure 3 is a perspective view from below of the device according to the present invention;

[0087] Figure 4 illustrates , again in perspective view, the drilling device of the present invention used for drilling an aeronautical component ;

[0088] Figure 5 illustrates a section of the device of Figure 1 ;

[0089] Figure 6 illustrates an enlargement of said section;

[0090] Figure 7 illustrates , in exploded perspective view, the device of Figure 1 ;

[0091] Figure 8 illustrates the device of the present invention used with a robot ; Figure 9 illustrates the device of the present invention used with a cobot ;

[0092] Figure 10 illustrates , in lateral view, an alternative of the drilling device of Figures from 1 to 9 ; and

[0093] Figure 11 illustrates , in front view, the alternative of Figure 10 .

[0094] Preferred Embodiment

[0095] Number 1 denotes , as a whole , in the attached figures , a drilling device .

[0096] The drilling device 1 comprises ( see in particular Figures 5 , 6 and 7 ) :

[0097] - an external support element 2 that extends along an axis H;

[0098] - a central tubular element 3 with axial symmetry carried by the external support element 2 and sliding with respect to the external support element 2 along the axis H in opposite directions .

[0099] The central tubular element 3 is provided at a first end 3-a, with an annular end edge 4 provided with three trapezoidal abutment teeth 5 that extend along the axis H, have flat end portions coplanar with a plane P perpendicular to the axis H and are equally angularly spaced around the axis by 120 ° ; the central tubular element 3 has a second end 3-b configured to house in a radially fixed manner a cylindrical portion 7 of a drilling head 8 provided with a drilling tool 9 ( see Figure 1 ) , for example a rotating drilling tip . The drilling head 8 is rotated by an electric motor (not illustrated for simplicity) .

[0100] The drilling device 1 also comprises an elastic element 10 ( described in detail in the following) which is interposed between the external support element 2 and the central tubular element 3 and extends axially . The drilling device 1 finally comprises a suction cup element 12 integral with a first end 2 -a of the external support element 2 and provided with an annular end portion 13 that extends around the axis H along a path that externally surrounds the end edge 4 in a radial direction .

[0101] As will be better explained in the following, the annular end portion 13 ( see Figure 4 ) is configured for fluid-tight resting on an external surface 15 of an aeronautical component 17 subj ect to drilling . Furthermore , the suction cup element 12 is provided with a connection member 20 with a device for creating a vacuum of a known type and therefore not illustrated . The suction cup element 12 is made of deformable material , such as rubber .

[0102] The suction cup element 12 is placeable , in use , following the creation of the vacuum inside the same , in a configuration in which it is firmly connected to the surface 15 and the central tubular element 3 can be advanced axially until the three abutment teeth 5 rest on the surface 15 defining a stable position of the central tubular element 3 with respect to the surface 15 and the elastic element 10 is compressed by the force exerted by the drilling head 8 .

[0103] The external support element 2 comprises ( see in particular Figure 7 ) : a flat disk element 22 transversal to the axis H and provided with a central circular through opening 23 coaxial with the axis H and configured to allow the sliding of the central tubular element 3 ; and

[0104] - a bell-shaped tubular element 24 with a diameter decreasing towards a tapered end having an end with a greater radius stably connected to the flat disk element 22 and an end with reduced radius defining a through opening 25 engaged by the central tubular element 3 , which is slidable with respect to the bell-shaped tubular element 24 . The tubular element with decreasing diameter 24 internally defines an inner chamber 27 that is in communication through channels 28 ( see Figure 6 ) with the inner cylindrical cavity 30 defined by the central tubular element 3 ; the inner chamber 27 is connectable by means of a connector 31 to a suction device (not illustrated) of the dust produced during drilling .

[0105] The central tubular element 3 comprises a first cylindrical tubular sleeve 33 connected in an axially fixed manner by means of known techniques to a second cylindrical tubular sleeve 34 having an outer diameter smaller than the inner diameter of the first cylindrical tubular sleeve 33 ; at an overlapping axial region between the first cylindrical tubular sleeve 33 and the second cylindrical tubular sleeve 34 , an annular housing 35 is formed, which extends axially and houses the elastic element 10 that is defined by a helical spring having a first end portion arranged in abutment on a shoulder 39 ( see Figure 6 ) of the annular housing 35 and a second end portion arranged in abutment on a shoulder 40 formed on the disk element 22 of the external support element 2 .

[0106] The second end 3-b of the central tubular element 3 is formed by the sleeve 33 and therefore the cylindrical portion 7 of the drilling head 8 can be inserted inside the sleeve 33 .

[0107] The first end 3-a of the central tubular element 3 is formed by the sleeve 34 and therefore the three abutment teeth 5 are formed on annular end edge 4 of the sleeve 33 .

[0108] With reference to Figure 3 , the suction cup element 12 has a plurality of chambers 43 ( eight in the example but the number may be di f ferent ) separated from one another and arranged in di f ferent angular positions around the axis H . The chambers 43 are each connected to the connection member 20 for creating the vacuum so that the suction of air inside each chamber 43 is independent .

[0109] In the embodiment, each chamber 43 extends for the same angular opening ( 45 ° ) around the axis H so that the chambers 43 have the same shape and the suction cup element 12 is symmetrical with respect to the axis H .

[0110] The suction cup element 12 has an annular shape and is defined by a curved side 45 made of deformable material ( rubber in the example ) and provided with a first outer annular end lip 46 and a second inner annular end l ip 47 coplanar with respect to one another and suitable for being arranged in sealed contact with said surface 15 .

[0111] The inner annular lip 12 has a diameter that is slightly greater than the diameter of the sleeve 34 ( see Figures 3 and 5 ) .

[0112] The curved side 47 is provided with a plurality of integral dividing partitions 49 ( these also made of a deformable material such as rubber ) that extend in a radial direction and are suitable for separating the adj acent chambers 43 .

[0113] In use , the drilling device 1 with the drilling head 8 inserted in the second end 3-b is carried by an arm of a robot R ( Figure 8 ) or by the arm of a cobot C ( Figure 9 ) . The robot R and the cobot C are of a known type and therefore are not further detailed .

[0114] As is known, a Cobot or co-robot ( the term derives from " collaborative robot" ) is a robot designed to physically interact with humans in a workspace , for this reason the cobot is generally mobile in the workspace whereas the robots are generally fixed .

[0115] Cobots are described in a 1997 US patent by Edward Colgate and Michael Peshkin, professors at Northwestern University, which describes cobots as " a device and method for direct physical interaction between a person and a computer-controlled manipulator" .

[0116] Robots R and / or cobots C are programmed to drill holes in an aircraft component 17 ( see Figure 4 ) , for example a portion of a vertical stabili zer of an aircraft V, illustrated schematically in Figure 9 .

[0117] For said purpose , the arm of the robot R / cobot C brings the suction cup element 12 into contact with the surface 15 of the aircraft component so that the axis H corresponds to the point where the hole is to be drilled .

[0118] The vacuum creation device is then activated and the suction element 12 connects strongly to the surface 15 . I f the contact of the lips 46, 47 on the wall 15 has discontinuities ( for example due to the presence of a hole already made ) , a single chamber 43 is depressuri zed but not the entire suction element 12 . In this way, thanks to the presence of many chambers , contact between the suction element 12 and the component 17 is guaranteed even in the absence of discontinuities or holes already present . By applying a thrust to the first sleeve 33 by means of the drilling head 8 ( for example by means of a linear movement of the robot / cobot arm) , the second sleeve 34 advances axially towards the component 17 until the three abutment teeth 5 rest on the surface 15 defining a stable position of the central tubular element with respect to the surface 15 and the elastic element 10 is compressed . The compression of the elastic element 10 ensures a high stability of the central element 3 on the component 17 since all the applied force is transmitted by means of three points ( the teeth 5 ) which have a small area and therefore exert a high pressure . The drilling head is then rotated and the drilling tool 9 penetrates the aeronautical component 17 following a further movement of the arm towards the aeronautical component 17 (my assumption) . During the drilling operations , the shavings and dust are sucked by the inner cylindrical cavity 30 and then reach the inner chamber 27 through the channels 28 . In this way, the shavings and dust can be removed without the same being dispersed into the environment . The drilling device 1 therefore does not disperse material into the environment during the processing operations . At the end of the drilling operations , air at atmospheric pressure is introduced into the suction cup element 12 which can be decoupled from the aeronautical component 17 and moved to obtain a new hole .

[0119] In the alternative illustrated in Figures 10 and 11 , three contact sensors 40c, 40b, 40c are provided and are equally angularly spaced around the suction cup element 12 and having an equal radial distance R1 with respect to the annular end portion 13 . The end portions of the sensors lie on the same plane PS as illustrated in Figure 10 . The contact sensors cooperate with the control unit of the Cobot C or the robot R to carry out the following operations .

[0120] The arm of the robot R / cobot C brings the suction element 12 into contact with the surface 15 of the aeronautical component and the position of the robot arm is then adj usted by a controller so that all three sensors touch the surface 15 and therefore the plane of the surface corresponds to the plane PS .

[0121] The vacuum creation device is then activated and the suction element 12 connects strongly to the surface 15 . By applying a thrust to the first sleeve 33 by means of the drilling head 8 ( for example by means of a linear movement of the robot / cobot arm) , the second sleeve 34 advances axially towards the component 17 until the three abutment teeth 5 rest on the surface 15 defining a stable position of the central tubular element with respect to the surface 15 and the elastic element 10 is compressed . The compression of the elastic element 10 ensures a high stability of the central element 3 on the component 17 since all the applied force is transmitted by means of three points ( the teeth 5 ) which have a reduced area and therefore exert a high pressure .

[0122] Numbers

[0123] 1 drilling device

[0124] 2 external support element

[0125] H axis

[0126] 3 central tubular element

[0127] 3-a first end

[0128] 4 annular end edge

[0129] 5 abutment teeth

[0130] P plane

[0131] 3-b second end

[0132] 7 cylindrical portion

[0133] 8 drilling head

[0134] 9 drilling tool

[0135] 10 an elastic element

[0136] 12 suction cup element 2-a first end

[0137] 13 annular end portion

[0138] R path

[0139] 15 external surface

[0140] 17 aeronautical component

[0141] 20 connection member

[0142] 22 disk portion

[0143] 23 circular through hole

[0144] 24 bell-shaped tubular element 24-a end with greater radius

[0145] 25 through opening

[0146] 27 inner chamber

[0147] 28 channels

[0148] 30 inner cylindrical cavity 31 connector

[0149] 33 first cylindrical tubular sleeve

[0150] 34 second cylindrical tubular sleeve

[0151] 35 annular housing 40c, 40b, 40c sensors

[0152] 39 shoulder

[0153] 40 shoulder

[0154] 43 chambers

[0155] 45 curved side 46 first outer annular end lip

[0156] 47 second inner annular end lip

[0157] 49 integral dividing partitions

Claims

CLAIMS1.- A drilling device characterized by comprising:- an external support element (2) that extends along an axis H;- a central tubular element (3) with axial symmetry carried by the external support element (2) and sliding with respect to the external support element (2) along the axis (H) in opposite directions; the central tubular element (3) being provided at a first end (3-a) with an annular end edge (4) provided with three abutment teeth (5) that extend along the axis (H) , have end portions coplanar with a plane (P) perpendicular to the axis (H) and are equally angularly spaced from one another around the axis of 120°; the central tubular element (3) has a second end (3-b) configured to house in a radially fixed manner a portion (7) of a drilling head (8) provided with a drilling tool (9) ,- an elastic element (10) is interposed between the external support element (2) and the central tubular element (3) and extends axially;- a suction cup element (12) integral with a first end (2-a) of the external support element (2) is provided with an annular end portion (13) that extends around the axis along a path (P) that externally surrounds the end edge (4) in a radial direction; the annular end portion (13) is configured for fluid-tight resting on a surface (15) of a component subject to drilling (17) ; the suction cup element (12) is provided with a connection (20) with a device for creating a vacuum; the suction cup element (12) is placeable, in use, following the creation of a vacuum inside the same, in a configuration in which it is firmly connected to the surface (15) and the central tubular element (3) can be made to advance axially by applying a thrust to the tubular element (3) by means of the drilling head (8)until the three abutment teeth (5) rest on the surface (15) , defining a stable position of the central tubular element with respect to the surface (15) and the elastic element (10) is compressed .2.- The drilling device according to claim 1, wherein the external support element comprises: a flat element (22) transversal to the axis H and provided with a central through opening (23) coaxial with the axis (H) and configured to allow the tubular element (3) to slide; and a tubular element with a decreasing diameter (24) towards a tapered end (24) having an end with a greater radius (24-a) stably connected to the flat element (22) , and an end with reduced radius defining a through opening (25) engaged by the central tubular element (3) , which is slidable with respect to the tubular element with decreasing diameter (24) .3.- The drilling device according to claim 2, wherein the tubular element with decreasing diameter (24) internally defines an inner chamber (27) that is in communication through channels (28) with the inner cavity (30) defined by the central tubular element (3) ; the inner chamber (27) is connectable (31) with a suction device of the dusts produced during drilling.4.- The drilling device according to any one of the preceding claims, wherein the central tubular element (3) comprises a first tubular sleeve (33) connected in an axially fixed manner to a second tubular sleeve (34) having an outer diameter that is lesser than the inner diameter of the first tubular sleeve (33) ; at an overlapping axial region between the first tubular sleeve (33) and the second tubular sleeve (34) an annular housing (35) is formed, which extends axially and houses the elastic element (10) that is defined by a helical spring having a first end portion arranged in abutment on a shoulder (39) of the annular housing (35) and a second end portionarranged in abutment on a shoulder (40) formed on a portion of the external support element (2) .5.- The drilling device according to any one of the preceding claims, wherein the suction cup element (12) has a plurality of chambers (43) separated from one another, arranged in different angular positions around said axis (H) and each connected with the connection member (20) for creating the vacuum.6.- The drilling device according to claim 5, wherein each chamber (43) extends by the same angular opening around the axis, so that the chambers have the same shape and the suction cup element (12) is symmetrical with respect to the axis (H) .7 The drilling device according to claim 5 or 6, wherein the suction cup element (12) has an annular shape and is defined by a curved side (45) made of deformable material and provided with a first outer annular end lip (46) and a second inner annular end lip (47) coplanar with one another and suitable to be arranged in sealed contact with said surface (15) to be drilled .8.- The device according to claim 7, wherein the curved side (47) is provided with a plurality of integral dividing partitions (49) that extend in a radial direction and are suitable to separate adjacent chambers (43) .9.- Device according to any one of the preceding claims, wherein three contact sensors (40c, 40b, 40c) are provided, arranged equally angularly spaced around the suction cup element (12) and having a radial distance R1 with respect to an annular end portion (13) of the suction cup element; the end portions of the sensors lie on the same plane PS.10.- A robot or cobot comprising an arm movable with respectto a component subject to drilling (17) and a drilling device made according to claim 9 and carried by said arm; the robot or cobot being provided with motorised means configured to operate said drilling head; said contact sensors (40c, 40b, 40c) cooperate with the control unit of the Cobot C or the robot R to perform the following operations : move the arm of the robot R / cobot C to bring the suction cup element (12) into contact with the surface (15) of the aeronautical component; regulate the position of the arm so that all three sensors touch the surface (15) and therefore the surface plane corresponds to the plane PS; activate the device for creating the vacuum so that the suction cup element (12) connects strongly to the surface (15) ; move the arm of the robot / cobot to apply a thrust that forms the support of the three abutment teeth (5) resting on the surface (15) defining a stable position of the central tubular element with respect to the surface (15) and the elastic element (10) is compressed.

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