FR2887941A1 - Helicopter rotor shock absorber fixing component has bolt with nut locked by looped spring clip to permit manual fitting and removal - Google Patents

Abstract

The fixing component consists of a bolt (29) and a nut (31) with a nut locking element in the form of a spring clip (35). The clip has a straight section formed by its two ends that is inserted through transverse holes in the nut and bolt, and a folded loop that clips over the nut and engages with an annular groove (55) in it. It is fitted and removed by lifting the loop - a movement that can be performed manually.

Description

Device for assembling parts of a rotorcraft.

  The present invention relates to a device for assembling parts of a rotorcraft, and to a rotorcraft comprising two parts assembled by such a device.

  The technical field of the invention is that of the manufacture of helicopter rotors.

  The invention relates in particular to an articulated assembly device of two parts of a rotorcraft rotor, in particular an articulated attachment device for a drag damper on a hub of the rotor of a helicopter, as well as a rotor of rotorcraft having two mutually articulated parts by such a device.

  It is known to attach a damper to the hub of a helicopter rotor and a rotor blade to damp the oscillations of the blade along its axis of drag; this attachment can be effected by means of a pivot or sleeve integral with the damper, the pivot being traversed by a shaft or bar secured to the hub by means of a clevis or equivalent structure - as described in patents FR 2733961 and US 5636970.

  Such an arrangement allows the damper to oscillate in rotation along the longitudinal axis of the shaft which is generally substantially perpendicular to the longitudinal axis of the damper.

  Such a shaft may consist essentially of a smooth portion of the body of a screw having a head and a body whose free end is threaded; the head can bear against an outer face of a first wall of the yoke, around a first bore provided in this wall and through which the body of the screw; the screw can extend into a second bore aligned with the first bore and provided in a second wall of the yoke; the smooth part of the screw body thus extends into the space or gap separating the two walls of the yoke, while the threaded end of the screw protrudes outside the second wall and receives a nut s' pressing on an outer face of the second wall of the screed.

  The smooth portion of the screw extending in the air gap delimited by the two walls facing each other receives the pivot or sleeve of the damper.

  This nut assembly must withstand the vibrations to which the joint and the rotor parts are subjected.

  This assembly must also be easily dismantled and reassembled in situ, in particular to allow the replacement of wear rings provided in the bores receiving the screw whose smooth central part forms the hinge shaft.

  These disassembly and reassembly operations of the joint must be performed quickly and without risk of damage to the articulated parts and / or parts of the rotor surrounding the joint.

  It is to these needs that the invention responds.

  The object of the invention is in particular to propose a device for articulating two parts of a rotorcraft rotor which is improved and / or which remedies, in part at least, the disadvantages or deficiencies of the known articulation devices of these rooms.

  According to a first aspect of the invention, there is provided a first locking means designed and arranged to immobilize in rotation the nut relative to the screw receiving it, the first locking means being releasable (removable) and engageable (insertable) manually, without requiring the use of a tool for its engagement or disengagement. For this purpose, the first locking means preferably comprises an elastically deformable pin or pin which forms a loop and comprises two portions intersecting each other.

  The invention makes it possible to immobilize the nut without using a pliers, a spanner, a screwdriver, or a pin extraction tool, which are usually necessary for the assembly or disassembly of such an assembly, and whose impact or the support against a piece of rotorcraft located near the assembly could be the cause of damage to it.

  The first locking means preferably comprises an elastically deformable pin or pin which comprises a first substantially straight portion designed and arranged to extend in two orifices (or cavities) substantially radial and coincident (coaxial) respectively provided in the nut and in the threaded portion of the screw, a second curved portion extending the first portion, which is designed and arranged to surround at least a portion of the nut and / or screw portion of the screw, and a third portion extending the second portion and overlapping (i.e. crossing) the first portion.

  According to a particular embodiment, the pin or pin has a fourth portion extending the third portion and forming a loop with the second and third portions.

  In a still more particular mode, the fourth portion is extended by a fifth substantially straight portion juxtaposed to the first portion.

  According to a preferred embodiment of the invention, there is further provided a second locking means designed and arranged to immobilize in rotation the nut relative to the wall against which it is supported, so that the nut can be tightened by rotating the screw without using a nut holding tool such as a wrench.

  Preferably, the second locking means comprises a tab or flange integral with the nut, extending substantially radially from the threaded body of the nut, and designed and arranged to bear on a locking face provided in the wall having a bearing surface against which the nut rests, this locking face forming an angle (not flat) with said bearing surface of the wall.

  According to a preferred embodiment, the nut comprises two such substantially diametrically opposed lugs or flanges (with reference to the screwing axis of the nut which corresponds to the axis of the bore and the hinge); in this case, the wall against which the nut is supported comprises two locking faces provided to respectively cooperate with these two lugs or wings.

  Although the second locking means is preferably integrated in the nut, according to an alternative embodiment it can be integrated with a separate piece forming a washer (cage) comprising indexing means (mutual rotational guiding) with the nut, such as notches or facets designed (e) s and arranged (s) to rely on complementary notches or facets provided (s) at the periphery of the nut.

  According to a still preferred embodiment of the second means of locking the nut relative to the wall, the two locking faces integrated in the wall are flat, parallel to each other, and perpendicular to the bearing face of the nut. surrounding the bore receiving the screw.

  Other features and advantages of the invention appear in the following description, which refers to the accompanying drawings and which illustrates, without any limiting character, preferred embodiments of the invention.

  Figure 1 is a schematic perspective view of an assembly device according to a first embodiment of the invention.

  FIG. 2 is an end view of the device of FIG. 1, and is a view along II of FIG.

  FIG. 3 is a partial longitudinal sectional view along III III of FIG. 2.

  Figures 4, 10 and 11 are plan views of three embodiments of a pin of a device according to the invention; the pin 2887941 5 illustrated in FIG. 4 is that illustrated in FIGS. 1, 2 and 5 to 7 while the pin illustrated in FIG. 10 is that illustrated in FIG.

  Figures 5 to 8 schematically illustrate in perspective a link articulated by a yoke according to the invention; FIG. 8 illustrates the clevis integral with an aircraft part while FIGS. 5 to 7 illustrate three distinct positions of engagement of the locking pin of an articulated assembly device according to the invention.

  Figure 9 is a schematic perspective view of a nut of an assembly device according to the invention.

  FIG. 12 illustrates, in side view, the deformation movements of a pin for its engagement or disengagement of a screw-nut assembly of a device according to the invention.

  FIG. 13 is a view from above of an articulated connection device according to the invention which is mounted on the yoke illustrated in FIG. 8.

  Figure 14 is a schematic perspective view of a nut locking piece according to an alternative embodiment of the invention.

  Fig. 15 is a perspective view illustrating the articulated connection of a drag damper to a helicopter rotor hub.

  Figure 16 is a view according to XVI of Figure 11.

  With reference to FIGS. 5, 8, 13 and 15 in particular, a hinge 21 with a yoke connects pivotally between two parts 22 and 23, along an axis 24; the yoke is integrated with the functional member 22 so as to constitute therewith a one-piece assembly; in the exemplary embodiments illustrated in these figures, each of the yokes connects between them a hub 22 of a rotorcraft and a shock absorber 23 of drag.

  Each yoke comprises two walls 25, 26 facing each other housing two wear rings 27, 28 fitted in two bores respectively formed in the walls 25, 26, along the pivot axis 24. These wear rings receive through a shaft 29 forming part of a screw having at its upstream end a head or member 30 for driving in rotation, and cooperating at its threaded downstream end 52 with a nut 31.

  This nut 31 is placed outside the yoke 25, 26, bearing against a face 40 of external support of the wall 25, while the base of the head 30 of the screw bears against an outer face 41 support of the other wall 25 of the yoke (see Figure 13).

  For immobilization in rotation, the nut 31 is engaged at the periphery of the wall 25 of the yoke against which it bears. For this purpose, the periphery of the wall 25 has flats 32 or similar locking facets. The nut 31 is equipped with a plate 33 comprising two angled tabs respectively for gripping two diametrically opposed flats 32 which the wall 25 comprises; the nut 31 can thus be immobilized in rotation on the yoke during the screwing of the shaft 29 therethrough, without requiring the use of a tool, because of the respective engagement of support legs 34 on the facets 32.

  At the end of screwing of the screw body 29, a pin 35 is put in place at the downstream end of the shaft 29 for locking the nut 31 thereon. For this purpose, the nut 31 comprises at its downstream end clearances 36 for passage of the pin 35, these clearances 36 being constituted by radial notches formed at the downstream end of the nut 31. As illustrated in FIGS. 5 to 7 and 15 in particular, the pin 35 comprises an elastically deformable loop 37 intended to surround at least a portion of the periphery of the nut 31, as well as a straight portion 38 intended to pass through the shaft 29 and the notches 36.

  In the variant embodiment illustrated in FIG. 14, the plate 33 carrying the locking tabs 34 is part of a part 53 distinct from the nut, which can be attached coaxially to the nut, unlike the other figures where the plate 33 is secured to the nut 31 with which it forms a one-piece assembly. In this variant, the part 53 comprises tabs 39 extending from a first face of the plate, this first face being opposite to that from which the tabs 34 for gripping the flats 32 extend. 39 are intended to grip flats formed on the nut, for a mutual connection in rotation of the part 53 and the nut 31.

  With reference to FIGS. 4, 10, 11 and 16 in particular, the pin 35 comprises a rectilinear, straight portion 38 intended to extend inside a diametrical channel 54 pierced in the screw (see FIG. 3), and the inside of two diametrically opposite grooves or notches 36 of the nut 31 The pin 35 further comprises a filamentary portion extending the portion 38; this second part comprises two elbows 43, 44 joined by a rectilinear portion 42 substantially parallel to the portion 38.

  A third straight filamentary portion 45 extends the bend 44 of the second portion and overlaps the first pin portion 38.

  These three portions form a loop 37, which in mounting position surrounds at least the half circumference of the nut.

  In the embodiment illustrated in FIG. 10, the third portion 45 is extended by a fourth portion comprising three elbows 46, 48 and 50 connected by two rectilinear portions 47 and 49. This embodiment facilitates manual gripping of the pin by its third and / or or fourth portions, and their elastic deformation necessary for engagement (and disengagement) of the pin.

  The embodiment corresponding to FIGS. 11 and 16 has the advantage of a reduced mass while facilitating the gripping of the pin by its third portion 45 as well as the deformation of parts 42 to 45.

  The embodiment illustrated in FIG. 4 is similar to that of FIG. 10; however, the fourth portion 46 to 50 is here extended by a fifth portion 51 which extends along the first portion 38 and forms therewith the pin passing through the screw, as shown in particular in Figures 1 to 3.

  In this embodiment, the section of the wire can be substantially twice as small as in the other embodiments while maintaining the same overall section in the central right portion (consisting of the straight portions 38 and 51) which passes through the axis 29 via its channel 54 to lock the nut 31.

  The braking efficiency is then as good as in other embodiments but with great flexibility of the pin, facilitating its introduction and removal.

  With reference to FIGS. 1 to 3 in particular, the engagement of the central part 38, 51 of the pin in two opposite radial grooves 36 of the nut and in the diametrical channel 54 passing through the threaded end 52 of the screw is rendered possible when the grooves extend in the extension of this channel.

  With reference to FIG. 3, the nut 31 has an internal annular groove 59 receiving a braking ring 60 engaged against the threads of the part 52 of the screw.

  With reference to FIGS. 7 and 12 in particular, this engagement is made possible by the elastic deformation of the pin, the portion forming the loop 37 remaining substantially flat and inclining with respect to a plane transverse to the axis 24 and containing the substantially common axis parts 38 and 51 of the pin which corresponds to the axis of the channel 54; this deformation movement corresponds to a distance from the first and third pin parts.

  This deformation obtained by manual effort on the pin portions forming said third portion (mark 45) and / or the loop, is facilitated by the polygonal shape (rectangular rounded corners) of this pin portion which is projecting relative to the periphery of the nut.

  Figures 6 and 12 illustrate the pin in a temporary position of partial engagement in the cavities 36 and 54 and around the nut 31, while Figures 1 to 3, 5 and 15 in particular illustrate the pin in a position of full engagement in cavities 36 and 54 and around the nut; in this position, the third pin portion 45 is returned, thanks to its elasticity, substantially in contact with the first portion 38 and the fifth portion 51 that it overlaps.

  To promote the retention of the pin in the latter position, an annular groove or groove 55 extends at the periphery of the nut 31 by connecting the radial grooves 36 to each other; as illustrated in FIG. 3 in particular, this groove receives a portion of the rectilinear portions 42 and 47 of the pin buckle.

  According to the preferred embodiment illustrated in Figure 13, the end 57 of the screw which is opposite its end 52 has a thread like the latter, instead of an integral projecting head as shown in Figure 3 in particular. In this case, a second nut 56 is screwed around the end 57 to bear on the outer face 41 of the wall 26 of the connecting yoke. In addition, the end 57 has a hollow recess 58 with an axis 24, for example an Allen key, which allows the rotation of the screw by a tool of shape adapted to that of this footprint.

  Such an embodiment allows the handling of the assembly, even in an inaccessible area with the usual tools (eye or pipe wrench): indeed, the shaft / nut assembly according to this embodiment can be tightened / loosened with a hexagonal key (called Allen key), which has the advantage of a small footprint.

Claims (16)

  1. Device for assembling parts (22, 23) of a rotorcraft comprising a screw (29), a nut (31), and a first removable locking means designed and arranged to immobilize in rotation the nut relative to the screw receiving, characterized in that the first locking means comprises a deformable pin or pin which forms a loop (37) and comprises two portions (38, 45) intersecting so that it can be engaged and manually released.   2. Device according to claim 1 wherein the pin or pin comprises a first portion (38) substantially straight designed and arranged to extend into two cavities (36, 54) substantially radial and coincidentally provided respectively in the nut and in the threaded portion (52) of the screw, a second curved portion (42 to 44) extending the first portion and configured and arranged to surround at least a portion of the nut and / or screw portion of the screw, as well as a third portion (45) extending the second portion and overlapping the first portion.   3. Device according to claim 1 or 2 wherein the pin or pin has a fourth portion (46 to 50) extending the third portion and forming said loop with the second and third portions.   4. Device according to claim 3 wherein the fourth portion is extended by a fifth portion (51) substantially straight and juxtaposed to the first portion.   5. Device according to any one of claims 1 to 4 wherein the nut comprises a peripheral groove (55) provided and arranged to receive a portion (42, 47) pin.   6. Device according to claim 5 wherein the nut comprises notches (36) substantially radial provided and arranged to receive a pin portion, these notches being connected by the outer peripheral groove (55).   7. Device according to any one of claims 1 to 6 wherein the loop has a polygonal shape with rounded corners.   8. Device according to any one of claims 1 to 7 which further comprises a second locking means designed and arranged to immobilize in rotation the nut relative to a wall (25) against which it is supported, so that the nut can be tightened by rotating the screw without using a nut holding tool such as a wrench.   9. Device according to claim 8 wherein the second locking means comprises a tab or flange (34) extending substantially radially from the nut and designed and arranged to abut on a face (32) provided for locking in a wall (25) of one of the parts to be assembled comprising a bearing face (40) against which the nut rests, this locking face forming a non-flat angle with said bearing face of the wall ( 25).   10. Device according to claim 9 wherein the second locking means comprises two such substantially diametrically opposed lugs or flanges, and wherein the wall against which the nut rests has two locking faces provided to respectively cooperate with these two legs. or wings.   11. Device according to any one of claims 8 to 10 wherein the second locking means is integrated with the nut.   12. Device according to any one of claims 8 to 10 wherein the second locking means is integrated in a separate part (53) forming a cage washer comprising indexing means (mutually rotational guide) with the nut, such as notches or facets (39) designed and arranged to rest on complementary notches or facets provided at the periphery of the nut.   13: Device according to any one of claims 10 to 12 wherein the two locking faces integrated in the wall are flat, parallel to each other, and perpendicular to the bearing face of the nut surrounding the bore receiving the screw .   14. Device according to any one of claims 1 to 13 wherein the screw comprises a smooth central portion.   15. Device according to any one of claims 1 to 14 wherein the screw comprises two ends (52, 57) threaded and a recess (58) recessed.   Rotorcraft rotor having a hub and damper affixed to the hub by a hinge having the features of any one of claims 1 to 15.