Patent Publication Number: US-2020290180-A1

Title: Fastening socket for assembling structures and associated attachment

Description:
The present invention relates to a fastening socket for assembling at least two previously drilled structures, said socket extending along a main axis between a first and a second open end, said socket comprising a substantially cylindrical body and an enlarged head, said enlarged head comprising first mounting surfaces capable of being assembled to a first installation component and for rotationally locking said first installation component about the main axis. 
     The invention applies particularly to temporary fasteners such as clamps. 
     Prior to the final assembly of two structural elements, it is known to carry out a temporary assembly of said elements by means of temporary fasteners inserted into through-holes. Such temporary fasteners are described in particular in document EP2247862. 
     During assembly of said temporary fasteners, a first mounting tool locks the socket in rotation in the through-hole while a second tool rotates a screw disposed in the socket. In this way, the socket must be locked firmly during screwing, which can be driven in a rotationally driven manner. 
     Furthermore, in the case of a mounting of the temporary fasteners made by an automaton, the fastener must be able to be gripped and moved easily by said automaton. 
     Finally, the fastener must be able to be completely removed from the through-holes by an automatic machine, even in the presence of mastic previously placed in the hole that potentially started to cure. 
     The temporary fasteners of EP2247862 document have in particular cross notches arranged in the socket head. These notches can cause insufficient locking of the socket, in particular when a large torque is exerted on the screw. Furthermore, such notches do not allow only sufficient gripping of the fastener by an automatic machine, which implies providing said automaton with additional gripping means. 
     The aim of the invention is to overcome these disadvantages. For this purpose, the subject of the invention is a fastening socket of the aforementioned type, comprising a first substantially cylindrical recess extending along the main axis from the first end, said first recess leading to a planar shoulder substantially perpendicular to said main axis, the first recess and the planar shoulder being received inside the enlarged head, the first mounting surfaces being formed by an inner surface of the first recess. 
     According to an advantageous aspect of the invention, the fastening socket is such that the first mounting surfaces comprise flats formed radially projecting or recessed relative to a cylindrical inner surface of the first recess. 
     The invention further relates to a fastener for assembling at least two previously drilled structures, comprising a socket as described above and an elongated element, movable inside the socket, said elongated element comprising a substantially cylindrical rod and a head arranged at a first end of said rod, said head of the elongated element comprising a second substantially cylindrical recess extending along the main axis, said second recess comprising second mounting surfaces adapted to be joined to a second installation element and to rotationally secure the elongate element and said second installation element about the main axis. 
     According to other advantageous aspects of the invention, the fastener comprises one or more of the following features, taken separately or according to all technically possible combinations:
         the socket comprises an inner ring for axially guiding the rod of the elongate element, said ring extending radially from an inner surface of the body;   the shank of the elongated element is provided with a thread;   the fastener further comprises a hooking element comprising: a base capable of sliding in the socket along the main axis, said base comprising a central opening; and tabs connected to said base around the central opening, said tabs extending through the second open end of the socket, each tab comprising a hooking nose; the elongated element being movable along the main axis in the central opening of the base, so as to radially move the legs between a retracted position and an extended position;   the central opening of the base is provided with a thread complementary to the thread of the shank of the elongate element;   a second end of the elongated element comprises a lug extending along the main axis from the rod, said lug having a transverse dimension smaller than a transverse dimension of the rod, the fastener further comprising a ring assembled to said lug, said ring forming an axial stop with respect to the base of the hooking element;   the ring comprises a first and a second substantially cylindrical portions, aligned axially, said first and second portions having respectively an outer diameter smaller than and greater than a minimum diameter of the central opening of the base, a junction between said first and second portions forming the axial stop.       

     The invention further relates to a setting nose for assembling a fastener as described above with at least two previously drilled structures, said setting nose comprising: a first installation element having a tubular shape, said first installation element having a front portion able to fit into the first recess of the enlarged head of the socket, said first installation element being configured to join with the first mounting surfaces of the enlarged head so as to lock the socket in rotation about the main axis, and a second installation element arranged inside the first installation element, said second installation element comprising a tip configured to fit into the second recess of the head of the element and to join the second mounting surfaces, the second installation element being capable of exerting a torsional torque on said elongate element. 
     According to an advantageous aspect of the invention, the setting nose comprises one or more of the following features, taken separately or according to all technically possible combinations:
         the setting nose further comprises a tubular blocking element movable in rotation inside the first installation element, the second installation element being arranged inside said blocking element, an axial end of said blocking element having a collar extending radially outwards, the front part of the first installation element and the collar respectively have a first and a second radial surface of identical cross-section, the setting nose being such that, in a first so-called installation configuration, said first and second radial surfaces are axially aligned, said collar thus being able to fit into the first recess of the enlarged head of the socket in such a way as to bear axially on the one hand against the planar shoulder of the socket and on the other hand against the front part of the first installation element;   the first and second radial surfaces are configured such that, in a second so-called locking configuration, a portion of the second radial surface forms an outer projection with respect to the first radial surface.       

     The invention further relates to an assembly for installing a fastener, said assembly comprising a fastener as described above and a setting nose as described above. 
     According to an advantageous aspect of the invention, said attachment and said delivery nose are configured such that, in the second locking configuration, the collar is able to be axially locked between the planar shoulder and the first mounting surfaces of the socket. 
    
    
     
       The invention will be better understood on reading the following description, given solely by way of non-limiting example and made with reference to the drawings, in which: 
         FIG. 1  is a cross-sectional view of a socket according to a first embodiment of the invention; 
         FIGS. 2 and 3  are views, respectively lateral and in cross section, of a fastener comprising the socket of  FIG. 1 ; 
         FIG. 4  is a perspective view, in cross section, of a fastener comprising the socket according to a second embodiment of the invention; and 
         FIG. 5  is a side detailed view of an installation assembly comprising the attachment of  FIG. 4  and a setting nose according to a first embodiment of the invention; 
         FIG. 6  is a cross-sectional view of the setting nose of  FIG. 5 ; 
         FIG. 7  is a detail view of the setting nose of  FIGS. 5 and 6 ; 
         FIGS. 8 and 9  are perspective detail views of the fitting nose of  FIGS. 5 to 7 , respectively in a first and a second configuration; and 
         FIG. 10  is a cross-sectional view of a setting nose according to a second embodiment of the invention. 
     
    
    
       FIGS. 2 and 3  show a fastener  10  according to a first embodiment of the invention, comprising a fastening socket  12  according to a first embodiment of the invention. The socket  12  is shown only in  FIG. 1 . 
       FIG. 4  shows a fastener  110  comprising a fastening socket  12  according to a second embodiment of the invention. 
     In the following description, the fasteners  10  and  110  and the sockets  12  and  112  will be described simultaneously, the common elements being designated by the same reference numbers. 
     In the embodiments shown, the fastener  10 ,  110  is a removable attachment, intended for the temporary assembly of two previously drilled structures (not shown). Alternatively, the socket  12 ,  112  is incorporated into another type of fastener, for example a permanent fastener. 
     The fastener  10 ,  110  extends along a main axis  14  defining an axial direction, and comprises: the socket  12 ,  112 ; an elongate element  16 ; a hooking element  18 , an assembly ring  20  and a bearing washer  22 . 
     The socket  12 ,  112  has a substantially tubular shape, extending along the main axis between a first  30  and a second  32  open ends. The socket  12 ,  112  comprises a body  34  and an enlarged head  35 . 
     The body  34  has an outer surface  36  and an inner surface  37 , which are substantially cylindrical. The outer surface  36  is cylindrical of revolution. The inner surface  37  has an anti-rotation shape. The inner surface is preferably formed of flats and has, for example, a hexagonal or octagonal cross-section. 
     In the embodiments shown, the enlarged head  35  has a frustoconical outer surface  38  intended to be placed in a countersink of one of the structures to be assembled. The enlarged head  35  also has a flat surface, substantially perpendicular to the main axis  14  and forming the first end  30  of the socket  12 ,  112 . 
     The enlarged head  35  comprises a first substantially cylindrical recess  40 , extending along the main axis  14  from the first end  30 . In the embodiments shown, the first recess  40  comprises in particular an inner cylindrical surface  42  of revolution. 
     The first recess  40  ends axially on a first shoulder  44 , received inside the enlarged head  35 . The first shoulder  44  is planar and substantially perpendicular to the main axis  14 . In the embodiments shown, the first shoulder  44  has an annular shape. 
     The first recess  40  has, in particular, a depth  45  along the main axis  14 , between the first end  30  of the socket  12 ,  112  and the first shoulder  44 . 
     The enlarged head  35  further comprises first mounting surfaces  46  capable of blocking the recess  40  in rotation about the main axis. Said first mounting surfaces  46  have an anti-rotation shape and are preferably formed of flats, arranged in axially extending planes. The flats  46  extend from the first end  30  of the socket  12 ,  112  but do not reach the first shoulder  44 . 
     In the embodiments shown, the flats  46  project radially with respect to the cylindrical inner surface  42 , such that a diameter passing through the centers of the flats  46  is less than the largest diameter of the first shoulder  44 . 
     Said shoulder  44 , an axial end of the flats  46  and the cylindrical inner surface  42  thus define a hollow volume  47 . 
     Alternatively, the flats are formed recessed relative to said cylindrical inner surface. 
     The first recess  40  is extended axially by a circular groove  50 , said groove having a diameter smaller than the diameter of the cylindrical inner surface  42 . The groove  50  ends axially at a second plane shoulder  52 , substantially perpendicular to the main axis  14 . The groove  50  and the shoulder  52  are in particular capable of receiving the washer  22 . 
     As can be seen in  FIGS. 1 and 2 , the shoulder  52  of the socket  12  opens radially on the inner surface  37  of the body  34 . On the other hand, as can be seen in  FIG. 4 , the shoulder  52  of the socket  12  is extended radially by a ring  54  projecting relative to the said inner surface  37 . The ring  54  comprises a circular orifice  56 , arranged along the main axis  14 . 
     The second end  32  of the socket  12 ,  112  comprises a crimping flange  58 . In  FIGS. 1 to 6 , the crimping flange  58  is shown before deformation. 
     The elongate member  16  extends along the main axis  14  between a first  60  and a second  62  end. The elongated element  16  comprises a substantially cylindrical rod  64 , as well as a head  66  and a lug  68  arranged respectively at the first  60  and the second  62  ends of said elongated element. 
     In the illustrated embodiments, the rod  64  is a threaded rod. A maximum diameter of the rod  64  is less than a minimum transverse dimension of the inner surface  37  of the body  34 , allowing mobility of the elongate element  16  inside the socket  12 ,  112 . 
     In the case of the socket  112 , the maximum diameter of the rod  64  is substantially equal to the diameter of the circular orifice  56  of the ring  54 , said ring ensuring an axial guidance of the elongate element  16 . 
     The head  66  of the elongate element  16  has a cylindrical shape projecting radially with respect to the rod  64 . The head  66  has a planar end, substantially perpendicular to the main axis  14  and forming the first end  60  of the elongate element. 
     The head  66  of the elongated element  16  comprises a second recess  70  substantially cylindrical, extending along the main axis  14  from said first end  60 . The second recess  70  forms second mounting surfaces capable of being connected to an installation tool in order for said tool to rotate the elongate element  16 . 
     The second recess  70  is, for example, a multi-lobed impression, as described in the document EP2458232 in the name of the applicant. 
     The lug  68  extends along the main axis  14  and axially extends the rod  64 . A diameter of said lug is less than a minimum diameter of the rod  64 . 
     The lug  68  comprises a crimping flange  72  forming the second end  62  of the elongate element. In  FIGS. 3 and 4 , the crimping flange  72  is shown before deformation. 
     The hooking element  18  comprises a base  80  and at least two tabs  82  connected to said base  80 . In the embodiments shown, the hooking element  18  comprises four identical tabs  82 . 
     The base  80  of the hooking element  18  has a substantially cylindrical shape and has an outer surface  84  of complementary shape to the inner surface  37  of the body  34 . The base  80  is thus able to slide in the socket  12 ,  112  along the main axis  14 , while being locked in rotation in said socket. 
     The base  80  comprises a central opening  86  arranged along the main axis  14 . The central opening  86  is provided with an internal thread that is complementary to the thread of the rod  64  of the elongate element  16 . 
     The tabs  82  are arranged around the central opening  86  and extend axially from the base  80 , through the second open end  32  of the socket  12 ,  112 . One end of each tab  82  is formed by a hooking lip  88 . 
     The tabs  82  and/or their junction with the base  80  have certain elasticity. More specifically, the tabs  82  are movable relative to the main axis  14  between a retracted position, in which the hooking lips  88  are in contact with each other, and a deployed position, in which said hooking lips  88  are spaced radially from one another. 
       FIGS. 2, 3 and 4  show the attachment  10 ,  110  in the retracted position.  FIG. 5  shows the attachment  110  in the deployed position. 
     In the retracted position and in the deployed position, a maximum diameter at the hooking lips  88  is respectively smaller and greater than a diameter of the outer surface  36  of the body  34  of the socket  12 ,  112 . 
     The assembly ring  20  is assembled to the lug  68  of the elongate element  16  and to the central opening  86  of the base  80  of the hooking element  18 ; the assembly ring  20  thus assembles the elongate element  16  and the hooking element  18 . 
     More specifically, the assembly ring  20  is fixed axially with respect to the lug, being blocked on either side by the rod  64  and by the crimping flange  72 . Said flange is folded radially outwards after deformation. 
     On the other hand, the assembly ring  20  comprises a first  90  and a second  92  axially aligned portions. Each of the first  90  and second  92  portions has a cylindrical outer surface of revolution. 
     The first portion  90 , arranged on the side of the rod  64 , has an outer diameter less than or equal to a minimum diameter of the central opening  86  of the base  80 . In a so-called release configuration of the fastener  10 ,  110 , as shown in  FIGS. 3 and 4 , said first portion  90  is inserted into said central opening  86 . 
     The second portion  92 , arranged on the side of the crimping flange  72 , has, on the contrary, an external diameter greater than the minimum diameter of the central opening  86 . Thus, a junction between the first  90  and second  92  portions forms an axial stop with respect to the base  80 , preventing a separation of the elongate element  16  and the hooking element  18  in the disengaged configuration. 
       FIG. 5  shows an assembly  200  for installing the fastener  10 ,  110  in order to assemble two previously drilled structures. The assembly  200  comprises at least one fastener  10 ,  110 , as well as a setting nose  202  according to a first embodiment. The setting nose  202  alone is shown in  FIGS. 6 to 9 . 
       FIG. 10  shows in section a setting nose  302  according to a second embodiment. Each of the setting noses  202 ,  302  is able to be used for an installation of the fastener  10 ,  110 . In The following description, the setting noses  202  and  302  will be described simultaneously, the common elements being designated by the same reference numbers. 
     The setting nose  202 ,  302  comprises in particular a first  204 ,  304  and a second  206  installation element, as well as a body  208 ,  308  suitable for being assembled to an automaton (not shown). The setting nose  202  of  FIGS. 5 to 9  further comprises a blocking element  209 . 
     The first installation element  204 ,  304  is a tubular socket, extending along a setting axis  210 . The first installation element  204 ,  304  comprises a rear portion connected to the body  208 ,  308 , as well as a front portion  212 . 
     The front part  212  has a shape capable of being fitted into the first recess  40  of the enlarged head  35  of the socket  12 ,  112 . In particular, the front part  212  comprises a radial surface  214 ; said radial surface comprises curved surfaces of complementary shape to the cylindrical inner surface  42 , alternated with flats  215  complementing the flats  46  of the first recess  40 . 
     The front portion  212  further includes a planar end surface  216 . In the embodiment  302  of  FIG. 10 , the end surface  216  is intended to come into contact with the first shoulder  44  of the socket  12 ,  112 . 
     The second installation element  206  is arranged inside the first installation element  204 ,  304 ; said second element is movable in rotation and in translation about the setting axis  210  with respect to said first installation element  204 ,  304 . 
     The second installation element  206  comprises a shaft  220  and a tip  222 . Said tip  222 , in particular visible in perspective in  FIGS. 8 and 9 , is configured to fit into the second recess  70  of the head  66  of the elongate element  16 . 
     Furthermore, the second installation element  206  is connected to a motor of the setting nose  202 ,  302 , or of the automaton, or to a manual tool, so as to be able to exert a torsional torque on the elongate element  16 . 
     Preferably, the first recess  40  of the enlarged head  35  of the socket  12 ,  112  and the front part  212  of the first installation element  204 ,  304  are configured to fit in such a way as to temporarily secure the fastener  10 ,  110  and the setting nose  202 , the main axis  14  coinciding with the setting axis  210 . 
     More specifically, the depth  45  of the first recess  40  is chosen to be sufficiently large so that the friction between said first recess  40  and the front portion  212  compensate for the weight of the fastener  10 ,  110 . Said fastener can thus be transported by the automaton equipped with the setting nose  202 ,  302  without any other gripping than said setting nose. 
     The setting nose  202  of  FIGS. 5 to 9  will now be described more precisely. The blocking element  209  is arranged inside the first installation element  304 . The blocking element  209  is a tubular socket, extending along the axis of installation  210 , between a rear end  230  and a front end  232 . Adjacent to said front end  232 , the blocking element  209  comprises a central tubular portion  233 , an outer diameter of which permits the rotation of said blocking element inside the first installation element  204 . The front end  232  is made in the form of a collar extending radially outwards with respect to the central tubular portion  223 . The end surface  216  of the first installation element  204  is intended to come axially in contact with said collar  232 . 
     A radial surface  234  of the collar  232  has a cross-section identical to the radial surface  214  of the front portion  212  of the first installation element  204 . More specifically, the radial surface  234  has an alternation of flats  235  and arc portions  236  in a so-called installation position, shown in  FIG. 8 , the locking element  209  is in a first angular position relative to the first installation element  204 , such that the flats  235  and  215  are aligned. In the direction of the setting axis  210 , the length of said aligned flats  235 ,  215  is equal, within tolerances, to the depth  45  of the first recess  40  of the socket  12 ,  212 . 
     In said locking position, the locking element  209  is in a second angular position relative to the first installation element  204  such that the flats  235  are misaligned with the flats  215  of said first installation element. 
     An example of a mechanism for rotating the blocking element  209  is visible in  FIG. 6 . The rear part of the first installation element  204  comprises at least one lateral opening  240 . Said lateral opening  240  extends around the installation axis  210  according to an angular portion corresponding at least to a distance between the first and second angular positions of the blocking element  209 . 
     The setting nose  202  further comprises at least one pin  242  arranged radially in the lateral opening  240 . An inner end of the pin  242  is fixed to the rear end  220  of the blocking element  209 . An outer end  244  of said pin  242  forms a radial projection outside the first installation element  204 . The pin  242  is able to move in the lateral opening  240  about the installation axis  210 . 
     The setting nose  202  further comprises a tubular ring  250 , arranged around the body  208  and the rear part of the first installation element  204 . The ring  250  comprises a protruding rear portion  252 , for example a soft or grooved portion to facilitate its manual gripping. 
     Near a front end  254 , the ring  250  comprises at least one orifice  256 , having a shape substantially complementary to that of a section of the pin  242 . The orifice  256  has, for example, a slightly oblong shape, extending axially. 
     The outer end  244  of the pin  242  is housed in the orifice  256 . Thus, rotation of the ring  250  relative to the body  208  of the setting nose  202  allows the pin  242  to move in the lateral opening  240  and to drive in rotation the locking element  209 . A manual rotation of the ring  250  thus drives the rotation of the locking element  209  between the installation and locking positions. 
     Preferably, the setting nose  202  comprises two lateral opening assemblies  240 /pin  242 /orifice  256 , said two assemblies being arranged facing each other with respect to the axis  210 . 
     Other mechanisms of rotation of the locking element  209  can be used, in particular, suitable for rotating the blocking element by means of an automatic machine. 
     A method of installing the fastener  10 ,  110  using a setting nose  202 ,  302  will now be described. The fastener  10 ,  110  is initially in the disengaged configuration. In the case of the setting nose  202  of  FIGS. 5 to 9 , said setting nose is in the installation configuration of  FIG. 8 . 
     An automaton equipped with the setting nose  202 ,  302  grips the fastener  10 ,  110  by assembling the front portion  212  of the first installation element  204 ,  304  with the first recess  40  of the enlarged head  35  of the socket  12 ,  112 . The automaton then moves the fastener  10 ,  110 , thus assembled to the setting nose  202 ,  302 , up to a first and a second structure to be assembled, drilled by a through hole. 
     The automaton introduces the fastener  10 ,  110  into said through-hole until the enlarged head  35  abuts against a front face of the first structure. The socket  12 ,  112  is then received in the through-hole and the hooking lips  88  of the tabs  82  protrude from the second structure. 
     The front part  212  of the first installation element  204 ,  304  exerts an axial force against the enlarged head  35  in the direction of the first structure, in order to rotationally lock the socket  12 ,  112 . The automaton introduces the tip  222  of the second installation element  206  into the second recess  70  of the head  66  and then exerts a torsional torque on the elongate element  16 . The rotation of the rod  64  causes the thread of said rod to engage in the tapping of the central opening  86  of the base  80  of the coupling element. The elongated element  16  moves axially towards the hooking lips  88  of the tabs  82 . The second portion  92  of the assembly ring then radially spreads said hooking lips. 
     The rotation of the elongate element  16  is continued until the hooking lips  88  are in axial abutment against a rear face of the second structure and the head  66  is in contact with the second shoulder  52  and/or the elastic washer  22 . In the case of the socket  112 , the washer  22  is sandwiched between the head  66  of the elongate element  16  and the guide ring  54 . 
     Thus, the fastener  10 ,  110  engages the two structures to be assembled to each other. 
     A similar method, with a rotation of the elongate element  16  in the opposite direction, makes it possible to detach the fastener  10 ,  110  from the through-hole of said structures. The fastener  10 ,  110  can thus be reused. 
     In the case of the setting nose  202  of  FIGS. 5 to 9 , a variant of the above method makes it possible to lock the fastener  10 ,  110  to the said setting nose in order to facilitate the transport thereof. 
     More specifically, according to said variant, an operator grasps the fastener  10 ,  110 , and inserts the front portion  212  of the first installation element  204  and the collar  232  of the locking element  209  into the first recess  40  of the enlarged head  35  of the socket  12 ,  112 . The flats  215 ,  235  are then aligned with the flats  46  of the socket  12 ,  112 . The operator rotates the ring  240  in one direction, so that the locking element  209  reaches the locking position shown in  FIG. 9 . In this position, the arc portions  236  of the collar  232  are arranged in the hollow volume  47  of the cylindrical inner surface  42  of the first recess  40 , between the shoulder  44  and an axial end of the flats  46 . Thus, the socket  12 ,  212  is blocked axially inside the setting nose  202  and can be transported in any horizontal or vertical direction to the first and second structures to be assembled. 
     Once the fastener  10 ,  110  is secured to the structures to be assembled, the operator turns the ring  250  in the other direction, so as to replace the locking element  209  in the installation position and then to unlock axially the fastener  10 ,  110  of the setting nose  20 . 
     The axial locking of the fastener  10 ,  110  in the setting nose  202  by the locking element  209  allows the fastener  10 ,  110  to be transported in any direction without the risk of loss of said fastener. It also allows the fastening  10 ,  110  to be removed from the two structures by simply exerting a traction on the setting nose  202 , even if the mastic interposed between the structures to be assembled has hardened around the socket  12 ,  112 .