FR2494354A1 - AXLE-NUT FIXING DEVICE - Google Patents

Abstract

A 10 METAL SHAFT-NUT COMBINATION IS PARTICULARLY SUITABLE FOR THE REALIZATION OF A THREADED CONNECTION IN COMPONENT PARTS. THE SHAFT 12 IS INSERTED IN A HOLE 68 PRE-SHAPED IN THE PART SO AS TO RECEIVE A NUT 14. DURING THE ASSEMBLY, THE SHAFT AND THE NUT DEFINE OPPOSITE FIXING PARTS 34, 64 WHICH COME IN CONTACT WITH OPPOSITE FACES 35, 65 OF THE PART IN AREAS LOCATED RADIALLY OUTSIDE THE HOLE, AND OF THE CHARGE RELEASE AREAS 36, 54 EXTENDING CIRCUMFERENTIALLY WHICH ARE EXTERNALLY CONTIGATED TO THE HOLE, OR CONTACT WITH THE PART AND ITS LOAD ARE AVOIDED.

Description

1.

  The present invention relates to fasteners

  tion and, more particularly, a combination of a metalli-

  that threaded nut whose use is particularly des-

  with composite materials. The metal shaft must be inserted in a pre-formed hole in a piece of composite material

  site and the nut is screwed on this axis. The axle and nut

  end opposite fastening parts which come into contact with opposite sides of the part in areas

  arranged radially outside the hole.

  The bolt-nut combinations of the prior art have certain drawbacks when used with advanced technique composite structures. Such structures show a tendency to strip off at the edge of a hole drilled in the structure or in an area immediately adjacent to this edge. For this reason, state-of-the-art composite structures often require special securing combinations. The

  Bolt-nut combinations of the prior art have geometries

  sortings which cause the load of the composite structures to the right of the pre-formed hole or in an adjoining zone of the hole

  in which they are used, and therefore contribute

  drink at weakening, failures or destruction--

  tion of the composite material in this area.

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  attachment combinations tend to be more massive

  ves and heavier than necessary and their mechanical resistance

  that is only partially used. These combinations are therefore generally oversized when used with composite materials. It is therefore desirable to have a lighter threaded combination

  that the devices of the prior art, and which is specific

  only designed in terms of mechanical strength and geo

  metrics for applications involving materials

  posites. In addition, it is desirable to have a combination of

  fixation type of this nature, which charges a composite structure for its fixation without contributing to

  failure of the composite material. It is also desired

  table to have a combination of fixing this na-

  which can be produced simply and efficiently, and

  be installed using conventional methods.

  The metal axle-nut combination of the pre-

  sente invention comprises an elongated axis having a part

  externally threaded at one end and a part

  head tie at its opposite end. The axis is inserted in a preformed hole in a composite part so that the head part abuts against one face of the part and the threaded part extends beyond the opposite face of the part to screw the nut . The nut and the head part of the axle define opposite fixing parts which come

  in contact with the opposite faces of the part in zo-

  nes radially distant from the outside of the hole, faces

  that they subject to a certain charge. Each of the

  fixing ties includes a recess extending circum-

  or part of lightening contiguous to the hole so that contact with the workpiece and its load in this area are avoided. The previous combination allows by

  therefore reduce the problem of structural failures

  ture related to the use of fastening devices of the prior art with composite materials, The metal axis comprises a hollow core

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  extending through it, which constitutes a light fixing member having advantages over solid bolts of the prior art in their use with composite materials. In particular, the hollow core has a tail of smaller section, so that an elastic elongation can be induced in this tail without subjecting the composite material to excessive stresses. If desired, the

  axial mechanical resistance of the axis can be adjusted

  can vary its radial thickness while its shear strength can be improved by filling the core with

  appropriate composite materials. The axis can be

  killed by sheet metal, wire, tube or be machined in bars.

  The nut can be obtained by stamping. The nut and axle can-

  wind have interior and / or exterior surfaces for the introduction of a key, and be self-locking. The axis can

  have a protruding or level head portion.

  The present invention will be well understood during the

  following description made in conjunction with the drawings below

joints in which:

  Figure 1 is a sectional view of a embodiment

  reading of a sheet metal shaft and a nut according to the present invention, shown after mounting on a part; Figure 2 is an elevational view showing certain features of an embodiment of a nut according to the present invention; Figure 3 is a sectional view of part of the sheet metal shaft of Figure 1 before mounting; Figure 4 is a sectional view of part of a

  sheet metal axis according to a second embodiment of the pre-

  invention; Figure 5 is a sectional view of part of a sheet metal shaft according to a third embodiment of the present invention; Figure 6 is a sectional view of part of a sheet metal shaft according to a fourth embodiment of the present invention; Figure 7 is a sectional view of part of a

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  sheet metal axis according to a fifth embodiment of the pre-

  invention; Figure 8 is a sectional view of part of a sheet metal shaft according to a sixth embodiment of the present invention; Figure 9 is a sectional view of part of a

  sheet metal axis according to a seventh embodiment of the pre-

  invention; Figure 10 is a sectional view of part of a

  sheet metal axis according to an eighth embodiment of the pre-

  invention; Figure It is a sectional view of part of a

  sheet metal axis according to a ninth embodiment of the pre-

  invention; Figure 12 is a sectional view of part of a

  sheet metal axis according to a tenth embodiment of the pre-

  invention; and Figure 13 is a sectional view of part of a

  sheet metal axis according to an eleventh embodiment of the pre-

invention.

  In connection, now with the figures, a first

  embodiment of a metal axle-nut combination

  lon the present invention is shown in Figures 1 to 10. The combination 10 comprises a sheet metal pin 12 which is

  shown after mounting on a piece of composite material

  te S with a threaded nut 14, the characteristics and

  the functions will be described more fully below.

  The axis 12 comprises an elongated tail 16 generally-

  cylindrical, ending in ends 17 and 18.

  In one piece with the tail 16, near the end

  mite 17 and extending axially from this extremi-

  tee, there is an externally threaded portion of reduced diameter 20 which ends in an end face 22. The axis 12

  also includes a head portion 26 disposed at the end

  mite 18 from tail 16, This part 26 includes effective-

  part of the tail 16 which consists of an integral rim 30 extending outward from the tail

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  in a generally radial direction, the peripheral part

  external risk 32 of the rim 30 defines an annular surface

  re 34 which is intended to come into contact with the face 35 of

  the part S during the mounting of the axis 12. The radial part-

  inner ment of the rim 30 defines a concave recess 36 extending circumferentially, disposed between the end

  18 of the tail 16 and the contact surface 34 of the flange 30.

  This recess 36 serves to release the stresses exerted

  in ledge 30, the purposes and function of which will be described

more fully below.

  As shown in FIG. 1, the metal axis 12 comprises a hollow core 37, situated axially, which extends between the head part 26 and the threaded part 20, the tail 16 constituting the intermediate part. The head portion 26 includes an access opening 38 which communicates with the core

  hollow 37. The opposite end of the axis 12 comprises a bore

  sage 39 which is coaxial with the soul 37 and allows to make commun

  to screw, along the threaded part 20,1'me 37 with the face

  extreme 22. This bore 39 forms an inner surface of the

  with the introduction of a key which facilitates the mounting of

axis 12 with nut 14.

  The nut 14 of the combination 10 comprises an elongated body part 40. As shown in FIG. 1, the part

  comprises at one of its ends a tail 42 generally

  cylindrical and axially extending, which defines a

  outer peripheral surface 44 and an end face 46.

  Part 40 also includes a folded down radial base

  outwards 48 at the end of the tail 42 opposite

  laid from the end face 46, the exposed end of the base 48

  defining an end face 50. An opening placed axially-

  ment extends from the end face 50 in the body part 40 so as to define a recess 51 in the base 48 intended to receive the end 17 of the shank 16 when mounting the nut 14 on the axis 12. The opening also defines a threaded axial bore 52 extending in the tail 42 between the recess 51 and the end face 46, which is intended to come

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  engage in the threaded part 20 of the axis 12 during the assembly

  tightening with nut 14. As shown in Figure 1, the recess-

  ment 51 of base 48 has the general shape of a bell which

  defines an arc-shaped side wall 53 diverging radia-

  Lement outward when moving in the axial direction towards the end face 50. In a place immediately adjacent to the end face 50, the side wall 53 defines a

  annular release part 54, the purposes and function of which

tion will be described below.

  The nut 14 also includes a portion 56 of engagement-

  tool ment, hollow, elongated, axially extending, shaped

  hexagonal or some other geometric shape, which is distant

  radially from the body part 40 towards the outside of

  so as to define an exterior surface 58 and an interior surface

  60 for tool, Part 56 for tool engagement

  me at its end 61 in one piece with the body part thanks to a radial flange 62 extending between the base 48 and the end 61. As shown in FIG. 1, the flange 62

  cooperates with the end face 50 of the base 48 and with the end

  mite 61 of the tool engagement portion 56 so as to defi

  nin a contact surface 64 which is intended to come into contact

  tact with side 66 of part S when mounting the nut

14 on axis 12.

  To use combination 10, the sheet metal pin 12 is first installed by inserting the shank 16 and the threaded part 20 in a hole 68 pre-formed in the part S. The pin 12 is then advanced in the hole 68 so that the rim 30 of the head portion 26 abuts against the face 35 and that

  the threaded part 20 extends beyond the face 66 of the part

  ce S. The nut 14 is then mounted on the axis 12 in the conventional manner. In this respect, the internal tool surface of the axis 12, formed by the bore 39 in the threaded part 20,

  can be used in conjunction with surfaces for or

  til 58 and / or 60 of the nut for advancing and adjusting the nut 14 relative to the part S. The nut 14 may include

  an axial counterbore in the recess 51. This counterbore

  ge allows combination 10 to account for differences

7. 2494354

  thickness of the parts by allowing the shank 16 of the axis 12 to extend inside thereof, Once installed, the combination 10 has a definite advantage over the bolt-nut combinations of the prior art when they are used with parts comprising state-of-the-art composite structures. Such structures tend to cause delamination near the edge of a threaded hole extending through it. For this reason, a bolt-nut combination which exerts a load on the composite structure in line with the hole or in an area immediately contiguous to the hole, will contribute to causing a

  failure or destruction of the composite material. The com-

  pairing 10 avoids this problem by offering a

  mounting fixture with optional securing parts

  posed which define distant radial load zones-

  ment from the outside of the hole 68 along the faces 35 and 66 of the part S. This advantage is obtained by the cooperation of the annular recess 36 of the flange 30 of the axis 12 and the annular part 54 of the face end 50 of the base 48 of the nut 14, which allow the release of the charges in the area of the part S immediately adjacent to the hole 68. Thanks to this geometry, the combination 10 will only subject the part S to a fixing load in the zones defined by the contact of the surface 34 with the face 35 and of the surface 64

with face 66.

  Combination 10 can be effectively performed in the following manner. The sheet metal pin 12 is formed from a sheet metal blank so as to define the threaded part, the tail 16, the head part 26 and the hollow core 37

  using a pro-matrix manufacturing process

  gressives or to an eyelet making machine. The fi-

  external lets of the threaded part 20 are formed by a pro-

  yielded from rolling nets. The nut 14 is formed by a ma-

  progressive, and the internally threaded bore 52 can be machined by conventional tapping, The various key surfaces of the nut 14 and the axis 12 can be modified to

  will. The surfaces 58 and 60 of the engagement part of

  the 56 of the nut 14 can be formed so as to be

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  hexagonal, as shown in FIG. 2. Alternatively, the surfaces 58 and 60 could be formed so as to give lobed surfaces. Part of a variant of axis 12

  is shown in Figure 5, where the hollow core 37 has been extended

  due to the end face 22 of the threaded part 20 and the inner surface for the tool provided by the bore 39 a

been eliminated.

  The suit 10 can be designed in different ways.

  ons to make a self-locking threaded assembly. The nut

  14 may have a self-locking feature by

  tail weaving 42 in diametrically opposite places

  of the outer surface 44 contiguous to the end face 46.

  The crimping process will have the effect of giving this

  part of the tail 42 the elliptical shape shown in fig-

  re 2. The threaded part 20 of the axis 12 may have a

  similar self-locking characteristic along its part 72, the resulting elliptical shape being represented in the

  Figure 3. Alternatively, the tail 42 of the nut 14 and / or the par-

  threaded tie 20 of axis 12 may have parts of

  toggle having a generally elliptical or three-lobed shape, or else the nut 14 may have a threaded bore

52 having self-locking threads.

  In addition to the above features, the combination

  naison 10 is an adaptable fastening device which

  has several advantages over mas-

  sives of the prior art. The currently known solid fastening devices are generally oversized for applications with composite materials. However, the

  hollow configuration of axis 12 provides a combination

  light 10, particularly suitable for parts made of material

  composite line. The hollow core 37 gives the axis 12 a resistance

  sufficient axial mechanical force in most applications

  where composite materials come in. However, the re-

  axial mechanical resistance of axis 12 can be adjusted according to certain particular applications by making

  vary the radial thickness of the shank 16 and the part fi-

  letter 20. Furthermore, due to the presence of the hollow core

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  37, the tail 16 of the axis 12 has a smaller section, so that

  te that the elastic elongation can be induced in the tail without exceeding the limits of the support load of a part

  made of composite material. This characteristic gives better

  their constancy of subjection for variable temperatures, and under the effect of a fatigue load. In particular applications where the shear strength is

  is causing problems, the hollow core 37 can be replaced

  plaice of suitable materials, such as composite materials

  high mechanical strength, so as to strengthen the

  axis shear strength 12.

  Figures 4, 6, 7, 8, 10, 11 and 12 show variants of axis 12 incorporating various geometries for the head portion 26. The elements of the metal axes shown in these figures which are common to the elements

  represented in figure 1 have the same reference numbers

  this. In the embodiment shown in FIG. 4,

  the head portion 26 of the axis 12 has a more pronounced geometry.

  as the geometry shown in figure 1. More specific-

  ment, the rim 30 of this embodiment extends over a greater axial length from the end 18 of the

  queue 16. When axis 12 of this embodiment is under-

  placed at a limit load during the mounting of the axis 12 and the nut 14, the head part 26 will deform to take a shape similar to that of FIG. 1. This geometry therefore provides a head part 26 o the level of

  load to which the composite part S is subjected can be con-

controlled and limited.

  In the embodiment of the head part 26 shown in FIG. 6, the flange 30 does not end at the

  outer periphery 32 as in the case of the feedback mode

  Reading of FIG. 1. On the contrary, the rim 30 comprises an integral part 74 which defines a cylindrical part

  hollow generally extending in the axial direction and terminating

  not by an end portion 76 extending radially towards

  inside and axially distant from part 32. The

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  ties 74 and 76 form external and internal surfaces 78 and

  tool grips, respectively, which facilitate mounting

  tage of the axis 12 and the nut 14. These surfaces 78 and 80 can-

  may be hexagonal, lobe-shaped or other shaped. FIG. 7 represents an embodiment of the head part 26, where the rim 30 defines a part

  intermediate 82 generally U-shaped and extending axially

  Lement, which is disposed between the end 18 of the tail 16 and the outer peripheral portion 32 it connects. This geometry gives a head portion 26 having an outer surface 84 extending axially for the tool grip, which can be given a certain shape in order to facilitate

  mounting the axle 12 and the nut 14.

  FIG. 8 represents an embodiment

  axis 12 o the head portion 26 comprises a cap

  sant sealing and preventing access to the hollow core 37.

  This cap 86 has the shape of a cup which is imparted during the formation of the head portion 26. The cap 86 comprises a side wall 88, cylindrical and generally extending in the axial direction, which forms an external gripping surface of tool. The side wall 88 can have any of the geometries described above in order to facilitate

  mounting the axle 12 and the nut 14.

  Figures 10 to 12 show three variants of the axis 12 having head portions 26 which are not projecting and have a generally frustoconical shape, which

  are intended to be used with a part hole 68 comprising

  as a counterbore as shown in 98 in the figure

  Each of these embodiments comprises a head portion 26 which defines a contact surface 34 extending circumferentially and radially distant from the outside of the hole 68, as well as a recessed or release portion of

  stress 36 extending circumferentially between the surface

  this contact 34 and the end 18 of the tail 16. These embodiments of the axis 12 include a hollow core 37

  similar to that of the previous embodiments, and may

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  can be formed identically. Figures 10 and 11 show two embodiments where the head portion 26 includes an opening 38 for accessing the hollow core 37. In the embodiment of Figure 11, the outer peripheral portion 32 of the flange 30 is radially folded inwards so as to constitute a head portion 26 having a

  better mechanical resistance. Figure 12 shows a mo-

  o the head portion 26 comprises a cap portion 100 intended to seal the hollow core 37 and to

prevent access to it.

  The geometries of the embodiments of Figures to 12 include various head parts 26 which are flush and have the advantages mentioned above when they are

  used with parts made of composite material. More specific

  cally, the head portion 26 of these embodiments includes

  carries an axis l1 where the fixing load produced by the assembly

  the axle-nut is distributed over the radially outer part

  re-counterbore 98. This characteristic, as well as the

  presence of the hollow core 37, give these embodiments

  sation of load and mechanical resistance characteristics

  similar to those of the embodiments described above.

  Figures 9 and 13 show two modes of

  reading of an axis according to the present invention, where the core digs

  se 37 was formed by drilling a massive tail 16. The elements of each of the metal axes shown in these figures which are common to the elements shown in Figure 1 have the same reference numbers. The embodiment shown in FIG. 9 comprises a solid head portion 26 which defines a cylindrical external surface 90 extending in the axial direction to constitute a surface for taking a tool. The exposed end 92 of the head portion includes

  a recess 94 which extends axially from this former

  extremity. As shown in FIG. 9, the side wall 96 of the recess 94 constitutes an internal tool-taking surface, which with the external tool-taking surface 90

  can be any shape to facilitate assembly

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* ge of the axis and the nut 14. The embodiment of FIG. 13 includes a head portion 26 which is not projecting, is generally frustoconical and similar to those shown in FIGS. 10 to 12, and which has the same advantages. Note that the embodiment of Figure 13 includes a cap portion 100 similar to that of the embodiment of-Figure 12. However, the portion of Figure 13 defines an opposite end 102, which has a recess s' extending axially 104. The lateral part 106 of the recess 104 constitutes an internal tool-taking surface which may have the desired shape for the purpose

  to facilitate the mounting of the axle and the nut 14.

  The present invention is not limited to the examples

  ples of realization which have just been described, it is on the contrary susceptible of modifications and variants which

will appear to those skilled in the art.

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Claims (8)

  1 - Fixing device intended to be used with a part comprising a pre-formed hole, characterized in that it comprises: an elongated axis for insertion into the hole, this axis having a threaded part externally to one   of its ends, and a head portion at its end oppo-   seat which defines a first fixing part arranged in a   dialement outside the axis and a nut which is mounted on the axis, this nut comprising an elongated body part having at one of its ends a base coming into contact with the   part and an axial bore provided with threads on at least one part   tie of its length in order to receive by engagement the threaded part of the axis, and a second fixing part arranged radially outside the body part contiguous to the base, these first and second fixing parts serving to subject to a load for fixing the opposite faces of the part in zones radially distant from the outside of the   hole when mounting the nut and axle.   2 - Device according to claim 1, character-   in that the head part of the axis comprises a recess   circumferentially extending annular, arranged radially-   between the axis and the first fixing part, this   duly defining a load release zone which is arranged radially between the first fixing part and the hole where the head part is not in fixing contact with the coin.   3 - Device according to claim 1, character-   in that the head part of the axle reaches an axial load threshold during the mounting of the nut on the axle, which has the effect of limiting the fixing load applied to the   part by the first and second fixing parts.   4 - Device according to claim 1, character-   in that the head portion includes an exterior surface   re extending axially from tool grip for easy   ter the mounting of the nut and the shaft.   - Device according to claim 1, character-   in that the head portion includes an extended recess   axially forming an internal surface for taking hold of 14. 2494354   til to facilitate the mounting of the nut and the axis.   6 - Device according to claim 1, characterized in that the threaded part ends in an end face comprising an axial recess which provides an internal surface for tool taking to facilitate the mounting of the nut and the axis.   7 - Device according to claim 1, character-   se in that the axis comprises a hollow core extending sensi-   along its length from the head portion to   that, and at least partially, the threaded part.   8 - Device according to claim 7, characterized in that the axis is formed from a solid threaded element, the core being obtained by drilling.   9 - Device according to claim 7, character-   in that the axis is formed from a sheet metal blank   by a series of passages in progressive matrices.   - Device according to claim 7, character-   in that the head portion further comprises an opening   re access that communicates with the soul.