Abstract:
Tooling for molding with keys for the production of air intakes without clips of substantially tubular shape, comprises a self-supporting mandrel with keys comprising at least three sectors in the form of panels, namely at least two articulated sectors ( 3 ) retractable toward the center of the mandrel and a key sector independent from the other sectors and insertable between these latter, thereby, by abutment, to define, by their external surfaces, a continuous surface corresponding to the internal surface of the air intake, elements to lock in abutted position the sectors, and a control device, disconnectable from the mandrel, of the relative displacement of the movable sectors to place them either in a molding position by abutment of the sectors, or in an unmolding position by retraction of the sectors toward the interior of the mandrel.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to the production of air intakes for nacelles containing the engine group, particularly for a jet engine, for aircraft. 
     The nacelle has a substantially annular cross-section and defines between it and a central portion of the engine an annular so-called fan channel. 
     The wall of the nacelle defining the fan channel is treated acoustically and constitutes a sandwich formed from a central cellular core flanked, on the fan channel side, with an acoustically resistive layer and, on the other side, with a total reflector. 
     This wall is conventionally formed of several sectors or segments, generally three or four, butted together by clipping to constitute a substantially annular conduit. 
     It is also known to produce air intakes with the help of two clipped panels, substantially semicircular in cross-section, with the help of a mold having the shape of half of an air intake. This technology could be pursued to its limit so as to produce a fan channel panel that is not only of one piece but also without clips, if the shape of such a panel permitted demolding without disassembly or destruction of the mold, which is not the case, the wall of a fan channel being almost always of a re-entrant shape. 
     SUMMARY OF THE INVENTION 
     The present invention has precisely for its object the provision of tooling for molding with keys, permitting particularly the production of air intakes without clips. 
     In the present description, an air intake without clips is formed of a panel of a substantially tubular shape constituted by a sandwich comprising a central cellular core, a total reflector and a resistive layer disposed on the internal surface of the panel, said internal surface comprising no connections nor clips that could disturb the acoustic damping of the panel. 
     To this end, the invention has for its object tooling for molding with keys for the production in particular of air intakes without clips of substantially tubular shape, comprising:
         a self-supported mandrel with keys, comprising at least three sectors in the shape of panels, namely at least two articulated sectors retractable toward the center of said mandrel and a so-called key sector independent of the two other sectors and insertable between these latter, such that, upon abutting, there can be determined by the external surface a continuous surface corresponding to the internal surface of the air intake;   means to lock in abutted position said sector;   and, a control device, detachable from the mandrel, preferably automatic, for the relative displacement of the movable sectors to place them either in a molding position by abutting the sectors, or in an un-molding position by retraction of said sectors toward the interior of the mandrel.       

     According to a preferred embodiment, the tooling comprises:
         a mandrel with keys comprising four sectors, namely a fixed sector and flanked by two other sectors that are symmetrical and articulated on the fixed sector, and a key sector independent from the others and insertable between the two articulated sectors by means to lock in abutted position the sectors, the mandrel being thus self-supported;   a control device for the relative displacement of the sectors to place them either in a molding position by abutment of all the sectors, or in an un-molding position by retraction of the three movable sectors inwardly of said mandrel, the control device being disengageable from the mandrel, and,   means permitting the transport and rotation of the mandrel in its molding position, constituted by two movable flanges adaptable to the two ends of the mandrel, said flanges being connected by securement ties and provided at their center with a socket or the like for connection to drive means for said mandrel in rotation about its axis.       

     The device for controlling the displacement of the sectors is constituted for example by a structure for receiving the mandrel in vertical axial position, comprising:
         first fixed means on which the fixed sector rests   second movable means on which the key sector rests, these means being movable diametrically to the mandrel,   and third and fourth means, respectively for support of the two articulated sectors, said third and fourth means each comprising a carriage movable inwardly of the mandrel and carrying a drive means on which one of said articulated sectors rests.       

     Such a mandrel, once shaped, which is to say with its sector panels abutted and locked and provided with its flanges, can be disposed horizontally on a device for driving it in rotation so as for example the emplacement of draping, winding or banding of the elements or elements constituting the acoustically resistive layer of a panel of a monobloc fan channel without clips, then for the emplacement of other constituent elements of the panel. 
     For polymerization, either of the single resistive layer, or of the assembly of sandwiches constituting the panel as well as if desired to carry out the steps of baking or welding in complement of said polymerization, the mandrel is retrieved and placed in the oven or autoclave after withdrawal or not of the flanges. 
     To recover finally the panel, the flanges are (if desired) returned into position on the mandrel which is thus positioned vertically on the mounting/unmounting device of the mandrel. 
     The device is, after unlocking of the key sector, actuated so that in the first place it is moved in translation inwardly of the key sector, then, in the second instance, pivoting inwardly the two articulated sectors so as to disengage these three sectors from the air intake panel thus produced, which can then easily be withdrawn. 
     The device can then be actuated by a reverse process to reconstitute a mandrel in such shape as to produce another panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages will become apparent from the description which follows, of one embodiment of the mandrel and its associated tooling, which description is given solely by way of example and with respect to the accompanying drawings, in which: 
         FIG. 1  is a schematic perspective view from above of a mandrel of a shape in accordance with the invention; 
         FIG. 2  is a view identical to that of  FIG. 1 , showing the internal surface of the mandrel that is not visible in  FIG. 1 ; 
         FIG. 3  is a view of the mandrel of  FIG. 2  in retracted de-molding position; 
         FIG. 4  shows the mandrel of  FIGS. 1 and 2  provided with its transport and mounting flanges on a device for rotating the mandrel and on which for example is deposited a resistive layer; 
         FIG. 5  shows the mandrel of  FIG. 4  without its flanges, resting on a cradle, for placing in an autoclave; 
         FIG. 6  is a fragmentary perspective view of an example of structure of a mandrel according to the invention; 
         FIG. 7  is a detailed view of the structure of  FIG. 6 ; 
         FIG. 8  is a top plan view of the key sector of the mandrel of  FIG. 6  in line with the junction between the key sector and one of its adjacent sectors; 
         FIG. 9  is a perspective view of the tooling designed to permit the modification of the mandrel from the molding configuration of  FIG. 2 , to the un-molding configuration of  FIG. 3 ; 
         FIG. 10  shows the tooling of  FIG. 9  with, in place, the mandrel, partially represented; 
         FIG. 11  is a detailed view of the control means of the tooling of the locking of the key sector; 
         FIG. 12  is a detailed view of control of the movement of a tool carriage of  FIG. 9 ; 
         FIG. 13  shows the embodiment of a mandrel with three sectors, and 
         FIG. 14  shows the embodiment of a mandrel with five sectors. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIGS. 1 to 3 , there is shown schematically a mandrel  1  with keys, according to the invention, respectively in its molding configuration ( FIGS. 1 and 2 ) and in its unmolding configuration ( FIG. 3 ). 
     The mandrel  1  is of generally tubular shape and constituted by four sections or sectors, namely a so-called fixed sector  2  on opposite sides of which are associated two identical sectors  3 , called articulated sectors because they are connected to the fixed sector  2  each by a pair of hinges  4 . 
     The fourth sector  5 , called the key sector, is an independent sector interposed between the two articulated sectors  3 . It is lockable in place on the two adjacent sectors  3  by locks  6  ( FIG. 2 ) secured to the key sector  5  and coacting with keepers  7  fixed on the sectors  3  facing latches of locks  6 . 
     Sectors  2 ,  3 ,  5 , in the molding position of the mandrel  1 , define an external surface which corresponds to the internal wall in contact with the air flow which enters the fan channel of the air intake panel to be produced. 
     The placing of the mandrel in the un-molding configuration ( FIG. 3 ) takes place by retraction inwardly of the key sector  5 , after unlocking the locks  6 , then folding inwardly the articulated sectors  3  by rotation about the axis of the hinges  4 . The tooling necessary for this operation will be described later with reference to  FIGS. 8 to 11 . 
       FIG. 4  shows the mandrel  1  of  FIGS. 1 and 2  on which has been emplaced for example by winding, banding or draping a resistive layer  8  constituting one of the elements of an air inlet panel without clips in the sense defined above. 
     The mandrel  1  is inserted between two end flanges  9   a ,  9   b , connected by ties  10 , the flanges bearing by their periphery on the sector of the sections. 
     Along the axis of mandrel  1 , on the external surface of the flanges  9   a ,  9   b , are arranged sockets  11  permitting the transport of the mandrel and its emplacement on a device for driving in rotation (not shown) of the mandrel  1  about its axis disposed for example horizontally. 
       FIG. 5  shows the mandrel  1  of  FIG. 4 , without its flanges  9   a ,  9   b  and in place on a cradle  12  for passage for example into an oven or an autoclave to polymerize the resin of the resistive layer  8 . The mandrel  1  rests on peripheral shoes  13 . It is however to be noted that the mandrel  1  could enter the oven or autoclave without first having its flanges removed. 
       FIGS. 6 to 8  show an embodiment of the structure of the sectors of mandrel  1 . 
     In  FIG. 6 , there is shown a fixed sector  2 , an articulated sector  3  and a key sector  5 , all constituted by a framework formed by parallel uprights  14  interconnected on the internal side by parallel flanged cross-pieces  15  and, on the outer side, by a thin sheet  16  whose external surface defines the molding surface of the mandrel. 
     The locks  6  of the key sector  5  are fixed on reinforced lateral uprights  14 ′ and coact with keepers  7  also fixed on reinforced lateral uprights  14 ″ of the articulated section  3 . 
     Moreover, as can be seen in  FIG. 7 , the two elements  4   a ,  4   b  of each hinge  4  for articulation between the sectors  2  and  3  are fixed, on the one hand ( 4   a ) on the uprights  14  of the fixed sector  2  and, on the other hand ( 4   b ) on a plate  17  connecting two cross-pieces  15  of the sector  3 . 
       FIG. 8  is a fragmentary top plan view of the structure of  FIG. 6 , at the junction between the key sector  5  and one of the articulated sectors  3 . 
     The lock  6  is carried by a plate  18  itself fixed to the lateral upright  14 ′ of the key sector  5 . 
     The latch  19  of the lock passes through the wall of the upright  14 ′ and that of the lateral upright  14 ″ of the sector  3  and engages in the keeper  7 . 
     The latch  19  is moved with the help of means described later with reference to  FIG. 11 . 
       FIGS. 9 to 12  show an embodiment of the means adapted to place the mandrel  1  in one or the other of its molding configurations ( FIG. 1 ) and un-molding configurations ( FIG. 3 ). 
     These means comprise a tubular steel chassis  20  of generally octagonal shape, defining a first movement track  21  diametral to the octagonal structure, flanked by two symmetrical movement tracks  22 , converging in a direction substantially from one of the ends of said first track  21 . 
     The track  21  is defined by two horizontal parallel beams  23 . 
     At one of the ends of the track  21  is fixed on the beams  23  a crosspiece  24  carrying two pins  25  adapted to support and center in vertical position the fixed sector  2  of the mandrel. To this end, in the lower portion of the sector  2  ( FIG. 6 ) are disposed, at the end of two uprights  14 , sockets  26  adapted to engage over the pins  25 , as shown in  FIG. 10 . 
     From the other end of the beams  23  and on their upper surface are fixed two rails  27  extending substantially over a little more than half of the length of said beams. 
     On the rails  27  move, by means of shoes  28  ( FIG. 12 ), a carriage  29  whose end (outer side) carries a cross-piece  30  provided with two support and centering pins  31 , analogous to the pins  25  and adapted to receive sockets  32  analogous to the sockets  26 , provided at the lower end ( FIG. 6 ) of uprights  14  of the key sector  5 . 
     The carriage  29  is moved by a screw  33  driving a nut  34  secured to the carriage  29 . 
     The screw  33  turns in the carriage  20  and is provided at its external end with a return angle  35  for controlling the screw either manually or by pneumatic screwing. 
     The carriage  29  carries a post  36  supporting two devices for actuating two pairs of locks  6 .  FIG. 11  shows in greater detail the actuating device of the upper pair of locks of the key sector  5 . 
     Each device comprises a control rod constituted by two lateral returns  37  whose ends in the form of hooks  38  coact with the complementary ends  39  ( FIGS. 6 and 8 ) of the latches  19  of the locks  6 . 
     The locks  37  are articulated on a head  40  movable vertically in guide slides  41  fixed to the post  36 , under the action of the rod  42  of a jack  43  also fixed to the post. 
     The ends  38  of the returns  37  are held by guides  44  secured to the post  36 . 
     At the hood of the post is disposed, fixed to the carriage  29 , a second jack  43 ′ ( FIG. 9 ) for actuating the lower locks  6  by a mechanism identical to that of  FIG. 11 . 
     Each track  22  comprises two parallel beams carrying two rails  45  on which circulate by means of shoes a carriage  46  moved, like the carriage  29 , with the help of a screw  47  provided with an angle return  48 . 
     Each carriage  46  carries a drive and guide pin  49  adapted to be received in a suitable throat (not shown) provided at the lower end of each articulated sector  3 . 
     In  FIG. 10 , there is partially shown the mandrel  1  in molding position, directly over its rest position on the chassis  20 . The mandrel is simply disposed on the pins  25  (fixed sector  2 ), on the pins  31  (key sector  5 ) and on the pins  49  (articulated sectors  3 ), the carriages  29  and  46  being in one of their two end positions on their respective movement tracks  21  and  22 . 
     In this position of the carriage  29 , the returns  37  of the actuating devices for the locks  6  are located in the vertical plane defined by the four locks  6 . 
     To pass from the un-molding position of the mandrel  1  of  FIG. 3 , the unlocking of the locks  6  is effected by retracting the rod of the jacks  43 ,  43 ′, then the carriage  29  is moved in the direction of the center of the chassis  20 , the carriages  46  being still stationary and locked. 
     When the carriage  29  has reached its maximum retracted position, and even a little before this position is reached, the carriages  46  can be actuated, simultaneously or not, to cause to pivot inwardly the articulated sectors  3  by rotation about the axis of the hinges  4 , the sectors being driven by the pins  49 . 
     The sectors of the mandrel being thus positioned, it is easy to withdraw the molded envelope  8  ( FIG. 3 ). 
     The screws  33  and  47  are preferably controlled automatically by a control device (not shown) synchronizing the movements of the carriages  29 ,  46  to accelerate the manipulation, but said screws  33 ,  47  can be controlled manually with the help of a crank for example. 
     To reconstitute the mold, the reverse series of movements is carried out. 
     Once the mandrel has been shaped, after blocking the locks  6 , the control devices ( 37 ,  38 ) of said locks can be loosened and there can be removed from the chassis  20  the mandrel  1  which is self-supporting thanks to the locked key sector  5 , to provide it with the flanges  9   a ,  9   b  for transport and rotation. 
     The mandrel  1  is replaced on the chassis  20 , either after polymerization of the resistive layer so as to recover this latter, the other elements of the sandwich defining the air intake panel being emplaced according to other techniques, or after final polymerization of said sandwich, so as to recover the panel for its finishing, all the elements of the panel being emplaced on the mandrel from the outset. 
     There has been described above a preferred embodiment of the mandrel with keys, but it is to be noted that the mandrel according to the invention can comprise a number of sectors different from four, namely a lesser number, essentially three sectors, or a greater number, particularly five sectors. 
     In the version with three sectors, shown in  FIG. 13 , two sectors S 1  and S 2  are articulated one on the other about a fixed axis A of rotation and the third sector S 3  forming the key sector is independent and movable and can be inserted between the two others in the deployed position to constitute by abutment a continuous surface corresponding to the internal surface of an air intake. In the un-molding position, the key sector S 3  is first of all moved toward the center of the mandrel (position S′  3 ), then the sectors S 1 , S 2  are folded toward each other (positions S′  1 , S′  2 ). 
     In the five sector version, shown in  FIG. 14 , four sectors S 4  to S 7  are articulated relative to each other symmetrically about a fixed axis A of rotation, and a fifth sector S 8  is an independent key sector movable diametrically of the mandrel. 
     In the molding position, the sectors S 4  to S 7  abut. In the un-molding position of the mandrel, the articulated sectors S 4  to S 7  are first folded toward the center of the mandrel as shown at S′  4  to S′  7  in  FIG. 14 , then the key sector S 8  is moved toward the center of the mandrel at S′  8 . 
     Generally speaking, and no matter what the number of sectors, the mandrel comprises an independent and movable key sector, the other sectors being articulated to each other or movable so as to be retractable inwardly of the mandrel.