FR2685020A1 - Device intended for mounting a point tongue and a stock rail mutually combined on a sleeper - Google Patents

Abstract

The present invention relates to a device intended for mounting a point tongue and a stock rail mutually combined on a sleeper. This device (1) includes a slide chair (plate) (6) mounted floating on the sleeper (4) and bearing, via elastic bearing means (83), on a chair edge (49) which is immobilised firmly with respect to the sleeper (4). When such a device (1) is used for mounting a point tongue (2) and a stock rail (3) on a prestressed reinforced concrete sleeper (4) it makes it possible, despite the rigidity of such a sleeper (4), to reduce the stresses appearing in the point tongue (2), the stock rail (3) and the chair (6) when trains pass.

Description

 The present invention relates to a device intended for mounting a needle and a mutually associated counter-needle on a cross member, in particular a cross member in prestressed reinforced concrete, and comprising for this purpose a sliding bearing having a mean plane, a face bearing of the bearing on one face of the cross member, the bearing face of the bearing being planar and cutting perpendicularly the mean plane of the bearing, defining with it a preferred direction, means for receiving a counter-needle and a needle on the pad opposite the bearing face of the pad, respectively in a determined location relative to the pad and in a variable location relative to the pad and juxtaposed with the determined location of the counter-needle in a determined direction of said preferred direction, as well as means for mounting the bearing on the cross member.

 In the current state of the art, these mounting means are chosen and tolerated so as to ensure that the sliding bearing is immobilized as firmly as possible relative to the cross member, with the aim of preserving over time a precise positioning of the bearing. and, with it, of the corresponding needle against the crosspiece.

 Thus, the sliding pad is generally mounted in direct support on the crossmember, that is to say without the interposition of a sole, or else by interposing between them a rigid sole, and it is fixed on the crossmember by means of 'screwing members, namely generally lag bolts, passing through the bearing by toleranced holes as closely as possible, and in practice machined in the bearing.

 Such mounting has been satisfactory so far, as long as the sleepers used for mounting the switches and crossings were wooden sleepers.

 However, there is a tendency to gradually replace the wooden sleepers with prestressed reinforced concrete sleepers, even for the production of switches and crossings, and it has been found that in the case of switches and crossings thus mounted on prestressed reinforced concrete sleepers , the above-mentioned assembly resulted in the appearance of unacceptable stresses in the needle, in particular at its end which is fine and fragile, and in the counter-needle, in particular at the transition between the zone of the counter-needle having an incomplete shoe and the counter-needle area with a full shoe, as well as in the sliding pad itself, when passing trains.

 In fact, the wooden sleepers made it possible to alleviate these constraints by offering their own flexibility, which the prestressed reinforced concrete sleepers do not have.

 The object of the present invention is to remedy these drawbacks, that is to say to render the assembly formed by a sliding bushing and a cross member, in particular in prestressed reinforced concrete although the present invention may find its application in the case of sleepers of other types, sufficient flexibility to limit to acceptable values the stresses in the needle, the counter-needle and the sliding bearing.

 To this end, the present invention provides a device of the type indicated in the preamble, further characterized in that the mounting means of the bearing are chosen and / or toleranced so as to allow a limited clearance of the bearing relative to the crosspiece in all the directions of the bearing face of the bearing from a privileged position of the bearing with respect to the cross member, in that this device further comprises a bearing stop having a mean plane, means for firmly immobilizing the cushion stop relative to the cross-member, in a position in which the cushion stop is juxtaposed with the cushion in the opposite direction to said determined direction and the mean planes of the cushion occupying said privileged position and of the cushion stop substantially coincide, and in that the bearing stop and the bearing have towards each other means for elastic support of the bearing against the bearing stop in said opposite direction and in two directions perpendicular to the mean plane of the bearing and mutually opposite, from said privileged position.

 In other words, the present invention proposes to mount the bearing on the crosspiece in a floating manner, and to oppose the tendency of the bearing to move under the action of the forces to which the counter-needle and the needle in passing trains, a predetermined elastic resistance provided by pressing the bearing on the elastic support means themselves bearing on the bearing stop, which can in turn be considered to form a rigid whole with the cross.

 Thus, in spite of the rigidity that the cross member can have, in particular when it is made of prestressed reinforced concrete, it is possible to ensure the mounting of a mutually associated needle and counter-needle sufficient flexibility to avoid excessive stresses when passing trains, both in the needle and the counter-needle as in the bearing; this results in an increase in the longevity of the needle, the counter-needle and the bearing, as well as the possibility of admitting increased rolling forces and consequently increased passage speeds and / or loads.

 It will be noted that, despite the floating mounting of the bearing on the cross member, it is ensured that the positioning of the bearing relative to the cross member retains at all times any desired precision insofar as the elasticity of the elastic support means , combined with the immobility of the bearing stop relative to the cross member, ensures the maintenance of the bearing in the aforementioned privileged position when the needle and the counter-needle are not subjected to stresses, i.e. -in particular say outside the periods of passage of trains, while the support of the pad against the pad stop by means of elastic support means not only in one direction of the mean plane of the pad but also in two directions perpendicular to this mean plane and mutually opposite makes it possible to predetermine the displacement of the bearing at the time of the appearance of stresses in the needle and the counter-needle with the passage of the trains, i.e. ire to predetermine the position which the bearing then occupies with respect to the cross-member, within limits compatible with the respect of the geometrical conditions which the track must respect for safety reasons.

 Naturally, it is possible to envisage differentiating the device according to the invention according to the direction of the switchgear to which it must be integrated and according to whether it is located to the right or to the left in this switchgear, with reference to a observer placed in the center line of the track, facing the needle points. However, in accordance with current practice in the field of intermediate devices for mounting railway elements on a sleeper, also called small equipment, it is preferred that the pad and the pad stop are respectively symmetrical with respect to the corresponding mean plane, in particular with regard to the elastic support means, so as to allow the use of the same pad and the same pad stop whatever the direction of the concerned track device and the position of the pad and the pad stop in this track device, that is to say to authorize a standardization of the device according to the invention.

The elastic support means of the cushion against the cushion stop can have various embodiments but, according to a currently preferred embodiment, particularly simple and effective, these elastic support means comprise
- on the bearing stop two substantially flat abutment faces and disposed respectively on either side of the mean plane of the bearing abutment, forming between them a dihedral of determined angle so that each abutment face of the bearing stop is placed opposite a respective abutment face of the bearing occupying said privileged position, being parallel to this abutment face and respecting a continuous space with respect to it,
- Between each abutment face of the bearing stop and the respective abutment face of the bearing and engaged with each of them, an elastically deformable pad in compression and in shear.

 One of the aforementioned dihedral thus has the shape of a dihedral of concave angle while the other of these dihedrons has the shape of a dihedral of convex angle, the sum of these angles equaling 360 ". Preferably, these are the abutment faces of the bearing stop which form between them a concave dihedral while the abutment faces of the bearing form between them a convex angle dihedron.

 The arrangement of the abutment faces on the bearing of a device according to the invention hardly complicates the manufacture of this bearing, generally in the form of a locally machined foundry piece, in comparison with the manufacture of a bearing of Prior Art; producing the bearing stop, with its two abutment faces, and elastically deformable buffers in compression and in shear interposed between the bearing and the bearing stop can also be simple and inexpensive, the bearing stop being for example made in the form of a locally machined foundry piece then removably attached to the cross member and each pad in the form of a molded piece. I1 follows that the production of a device according to the invention is itself simple and does not entail a considerable additional cost in comparison with the production of a cushion of the prior art.

 Preferably, untimely displacements of the pads interposed between the pad and the pad stop are avoided by securing each of these pads with at least one of the corresponding abutment faces.

 To facilitate maintenance operations, however, in the event of wear or deterioration of the pads, it is preferred that, for this purpose, each pad and at least one of the corresponding abutment faces include removable mutual securing means. For example, in a particularly simple manner to carry out, effective as regards the mutual securing obtained and convenient as regards the possibility of changing a tampon, the means of removable mutual securing of a tampon with at least one of the abutment faces corresponding comprise at least one hole arranged in this abutment face and a respective elastically compressible tenon integral with the pad, engaged in this hole and dimensioned so that it is retained there in elastic compression preload.

 Each pad can thus be secured, in particular removably, with one and the other of the corresponding abutment faces, or even be secured only with one of them, which is sufficiently effective and facilitates in addition maintenance operations. In this regard, each buffer is preferably secured to the corresponding abutment face of the bearing stop which is itself, as indicated above, preferably produced separately from the cross member and attached removable on this cross member, in particular for reasons of ease of manufacture and maintenance, it being understood that it is more convenient to dismantle the bearing stopper for a certain number of maintenance operations than to dismantle the bearing, which carries the needle and the counter-needle.

 Thus, it is advantageously provided that the bearing stop has a bearing face on said face of the cross member, this bearing face of the bearing stop being plane and perpendicular to the mean plane of the bearing stop, and that the means for firmly immobilizing the bearing stop relative to the cross-member are means for mounting the bearing stop on the cross-member, chosen and / or tolerated so as to ensure said firm immobilization, it being understood that d other embodiments of a bearing stop firmly immobilized with respect to a cross member could be envisaged without departing from the scope of the present invention, and in particular an embodiment of the bearing stop under shape integrated directly into a cross member.

 For example, in a way directly inspired by the traditional mounting of the bearings on the crosspieces, it can be provided that the means for mounting the bearing stop comprise a rigid sole in compression and in shear, interposed between the bearing face of the bearing stop and said face of the cross member, and means for clamping the bearing stop on said face of the cross member perpendicular to the bearing face of the bearing stop; also directly inspired by the traditional mounting method of the bearings on the crosspieces, it is possible to provide for these clamping means to include holes passing through the bearing stopper perpendicularly to its bearing face and members for screwing the stopper bearing on the crosspiece, through said holes, said holes being dimensioned so that there is practically no play around each screw member.

 The mounting of the bearing can also be inspired by the traditional mounting of the bearings except that, typically, it is floating rather than being rigid.

 According to a currently preferred embodiment, the mounting means of the bearing comprise an elastically deformable sole in compression and in shearing, interposed between the bearing face of the bearing and said face of the cross member, and means for clamping the bearing on said face of the cross member perpendicular to the bearing face of the bearing; advantageously, these clamping means comprise holes passing through the bearing perpendicular to its bearing face and members for screwing the bearing on the cross-member, through said holes, said holes being dimensioned so that remains around each screwing member continuous play in said privileged position of the bearing.

 Naturally, insofar as the production of the device according to the invention involves modifications of the sliding bushing in comparison with the sliding bushings of the prior art, on the one hand, and the production of a bushing stop for its part Newly introduced, the present invention relates not only as a whole to a device for mounting a needle and a mutually associated needle against a cross member, but also the sliding bearing and the bearing stop considered individually and having the characteristics specific to the production of the device according to the invention.

 Other characteristics and advantages of this device as well as of the sliding pad and of the pad stop which it comprises will emerge from the following description, relating to a nonlimiting exemplary embodiment, as well as from the appended drawings which show an integral part of this description.

 - Figure 1 shows a sliding pad according to the invention, in a top view.

 - Figures 2 and 3 show views of this pad in section through planes identified in II-II and III-III in Figure 1, respectively.

 - Figure 4 shows a partial view of this bearing in section through a plane identified in IV-IV in Figure 1.

 - Figure 5 shows a view of this pad along the arrow marked in V in Figure 1.

 - Figure 6 shows a partial view of this pad along the arrow marked in VI in Figure 1.

 - Figure 7 shows a top view of the bearing stop.

 FIG. 8 shows a view of this bearing stop in section through planes marked in VIII-VIII in FIG. 7.

 - Figure 9 shows a view of an elastic support pad of the pad on the pad stop, in side elevation.

 - Figure 10 shows a view of this buffer along the arrow marked in X in Figure 9.

 - Figure 11 illustrates the mounting of a needle and a counter-needle on a crosspiece by means of a device according to the invention, the sliding bushing being seen in section partly according to the plans marked in II-II in FIG. 1 and partly in section along the plane marked in IV-IV in FIG. 1 and the bearing stop being seen in section along the planes identified in VIII-VIII in FIG. 7.

 By convention, the device according to the invention 1 will be described with reference to the position it occupies when it assembles a needle 2 and a mutually associated counter-needle 3, that is to say forming the same half-switch, on a cross member 4, in particular of prestressed reinforced concrete, itself occupying its normal position of use, and more precisely on a flat face 5 then upper of this cross member 4, as shown in FIG. 11 .

 It will be observed that this FIG. 11 illustrates the use of a device according to the invention 1 in an area of a half-switch in which the pads 17 and 20 of the counter-needle 3 and of the needle 2 are incomplete and in which the needle 2 is capable of coming into direct contact, that is to say without an intermediate piece forming a stop, with the counter-needle 3; however, a device according to the invention 1 could naturally be used in any other zone of the switch.

 Reference will firstly be made to FIGS. 1 to 6 and II where a bearing 6 according to the invention has been illustrated, for example produced in foundry in the form of a single piece.

 This bearing 6 has a mean plane 7 with respect to which it is symmetrical and which is oriented perpendicular to the upper face 5 of the cross-member. Downwards, it has a machined flat face or lower face 8 which is perpendicular to the plane 7, which it cuts by defining with it a preferred direction 9, and which is intended to rest on the upper face 5 of the cross member 4 via a sole 10 of generally flat shape.

 In view of the implementation of the present invention and in a characteristic manner of the illustrated embodiment, this sole 10 is elastically deformable in compression and in shear between a lower face 11 placed in contact, flat, with the upper face 5 of the cross-member 4 and an upper face 12 parallel to the lower face 11 and placed in contact, flat, with the lower face 8 of the pad 6 with respective contact pressures such that mutual friction is established respectively between the lower face 11 of the sole 10 and the upper face 5 of the cross member 4 and between the upper face 12 of the sole 10 and the lower face 8 of the pad 6, due to the presence of means 13, described later, ensuring the tightening of the bearing 6 on the upper face 5 of the cross member, by means of the sole 10, perpendicular to the lower face 8 of the bearing 6 as well as to the face upper 5 of cross 4.

 The lower face 8 of the cushion 6 is delimited by connection to a song 14 of indifferent contour, if not locally as will appear below, which song 14 connects this lower face 8 to an upper face 15 of the cushion 6.

This upper face 15 is itself formed of a juxtaposition, parallel to the direction 9, of several faces turned upwards and each of which is symmetrical relative to the plane 7. Thus, this upper face 15 of the bearing 6 comprises
- A flat, machined face 16 for receiving the shoe 17 of the counter-needle 3 at a fixed, fixed location, relative to the pad 6 this face 16 is inclined relative to the underside 8 of the pad 6 so as to approach it in a specified direction 18 from direction 9
- A flat, machined face 19 for receiving and sliding the shoe 20 of the corresponding needle 2, juxtaposed against the counter-needle 3 but occupying a variable location with respect to the latter as well as with respect to the bearing 6; this face 19 is parallel to the underside 8 of the pad 6 and juxtaposed to the face 16 in the direction 18, by means of a groove 21 perpendicular to the mean plane 7 of the pad 6
- Two plane faces, machined, 22 and 23 for receiving the clamping means 13, each of these faces 22 and 23 being parallel to the lower face 8 of the bearing 6; the face 22 is juxtaposed with the face 19 for receiving and sliding the shoe 20 of the needle 2 in the direction 18 while the face 23 is juxtaposed with the face 16 for receiving the shoe 17 of the counter-needle 3 in the direction 24 opposite to meaning 18.

 These arrangements of the upper face 15 of the pad 6 are known in themselves and do not require further description; they are indifferent with regard to the present invention and could vary without departing from the scope thereof.

Likewise, in known manner, the bearing 6 comprises means 25 for receiving retaining members integral with the counter-needle 3 in its determined location relative to the bearing 6, these means 25 respecting the symmetry of the bearing 6 with respect to its medium shot 7 and comprising in the example illustrated
two holes 26 arranged in mutually symmetrical positions relative to the plane 7, perpendicular to the lower face 8 of the pad 6, under a rectilinear rib 27 oriented perpendicular to the mean plane 7 and arranged in relief on the upper face 15 of the pad 6, at the transition between the faces 23 and 16 thereof; this rib 27 is locally interrupted opposite each of the holes 26 which it however partially overlaps on either side so as to create localized undercuts making it possible to introduce and retain upwards, in each of the holes 26 , a respective oval or T-shaped bolt 28 receiving itself, above the rib 27 and from bottom to top, a toad 29 applying downwards on the one hand on the face 23 and on the other share on the shoe 17 of the counter rail 3, a respective Grower washer 30 in compression preload, a respective flat washer 31 and a respective nut 32 for tightening, according to a technique known per se
- A handle 33 for supporting in the direction 24 for the core 34 of the counter-rail 3 and for fixing the counter-needle 3 relative to the bearing 6 by means of this core 34; this handle 33 is made in one piece with the pad 6 and consists of two flanges 35 of the pad 6 and a strip 36 connecting these two flanges 35 mutually; the two flanges 35 are flat, parallel to the mean plane 7 with respect to which they are mutually symmetrical and are connected to the edge 14 of the pad 6 at the face 23; they protrude upward and in the direction 18 relative to the upper face 15 of the bearing 6, from their connection to the edge 14 thereof, so as to partially overhang the receiving face 16 of the pad 17 of the counter rail 3 without, however, hindering the passage of this counter rail 3 perpendicular to the mean plane 7 of the bearing 6; cantilevered directly above the face 16 for receiving the shoe 17 of the counter rail 3, the two flanges 35 bend towards the mean plane 7 of the pad 6 and are connected to each other by the strip 36 which is flat and perpendicular to this mean plane 7 to serve as a support for the core 34 of the counter rail 3 in the direction 24; in view of this support, the strip 36 has in the direction 18 a machined face 37 defined by generatrices perpendicular to the mean plane 7 of the pad 6 and having when it is seen in section along the mean plane 7 or parallel to it a shape complementary to that of the section of the core 34 of the counter rail 3 centrally with reference to this face 37, along an axis 38 disposed in the mean plane 7 and oriented parallel to the face 16 for receiving the pad 17 of the counter needle 3, the strip 36 is drilled right through a hole 39 for receiving a hammer head bolt 40 also passing through the core 34 of the counter rail 3 through a hole 41 thereof and bearing by its head, in the direction 24, against the core 34 of the counter rail 3 itself bearing in this direction 24 against the face 37 of the strip 36; opposite the latter, this nut 40 successively carries, in the direction 24, a Grower washer 42 bearing against the strip 36 and a nut 43 bearing against the washer 32 so as to tighten the core 34 of the counter-rail 3 against the face 37 of the strip 36.

 These provisions are also well known to a person skilled in the art and do not require further description; they are indifferent with regard to the present invention and could vary without departing from the scope thereof.

 However, typically the bearing 6 illustrated and in order to implement the present invention, the two flanges 35 are connected to each other not only at their overhang relative to the receiving face 13 of the shoe 17 of the counter-needle 3, and this by means of the strip 36, but also opposite the strip 36, at a localized area of the edge 14 which defines an end area 34 of the pad 6 in the direction 24 and in which the edge 14 has when the pad 6 is seen in plan a pointed shape in the direction 24, with symmetry with respect to the mean plane 7 of the pad 6. Along the edge 14 thus formed, the pad 6 has an integral part, by being produced in one piece, and projecting above its face 23 perpendicularly to its lower face 8, two flanges 45 flat, mutually symmetrical with respect to the plane 7 and oblique with respect to the latter, these two flanges 45 are connected ant in the direction of a distance from the plane 7 to a respective flange 35 while they are connected to each other along the plane 7. It is noted that the two flanges 45 form with the two flanges 35 and the pad 6 a completely rigid , able to resist significant efforts.

 In the direction 24, each of the flanges 45 is delimited by a respective flat face 46 perpendicular to the lower face 8 of the pad 6, the two faces 46 being mutually connected at the plane 7 by a transition facet 47 set back from they in the direction 18.

The two faces 46 are machined and form between them a dihedral with an angle a greater than 1800, also distributed on either side of the plane 7 with respect to which each of the faces 46 forms for example an angle a / 2 of the order 114 "+ 0.25, this figure being given by way of non-limiting example.

As will appear below, these faces 46 are intended to form part of means 83 for elastic support of the pad 6 in the direction 24 as well as in mutually opposite directions 48 perpendicular to the mean plane 7 of the pad 6, on a pad stop 49, visible in FIGS. 7, 8 and 11, juxtaposed with the pad 6 in the direction 24, without direct contact with this pad 6.

 In fact, also characteristic of the present invention, the mounting of the bearing 6 on the upper face 5 of the cross-member 4 by means of the sole 10 and thanks to the clamping means 13 is not a rigid mounting in accordance with the prior art, but a floating mounting, allowing limited travel of the bearing 6 in all directions of its lower face 8 relative to the cross member 4, from a privileged relative position constituting the mounting position of the bearing on the crosspiece and the position that this pad occupies in the absence of stress in the counter-needle 3 and the needle 2.

 This limited clearance is authorized by the elasticity of the sole 10, in particular in shear, and by the choice and tolerancing of the clamping means 13.

 In the example illustrated, the tightening of the cushion 6 on the upper face 5 of the cross-member 4 is ensured by threading and, for this purpose, the cushion 6 has four holes passing right through it perpendicularly to its lower face 8, with due to two holes 50 opening into the face 23 and mutually symmetrical with respect to the mean plane 7 of the bearing 6 and two holes 51 opening into the face 15 and mutually symmetrical with respect to this same mean plane 7.

 Each of these holes 50, 51 is essentially defined by an inner peripheral face 52, 53 cylindrical of revolution around a respective axis 54, 55 perpendicular to the lower face 8 of the bearing 6, into which each of these holes 50, 51 opens out. by a respective coaxial annular recess 56, 57; upwards, respectively in the face 23 and in the face 22, the holes 50, 51 open out by a frustoconical annular facet, coaxial, respectively 58, 59.

 Each of the holes 50, 51 is intended to receive, coaxially in the aforementioned privileged position of the bearing 6 relative to the cross-member 4, a respective lag screw 60, 61 also passing through the sole 10 through a respective through-hole 62, 63 thereof. .

 In a manner known in itself, each lag screw 60, 61 has a head 64, 65 which bears on the upper face 15 of the pad 6, and more precisely respectively on the face 23 or on the face 22, by the through a stack of washers engaged on its rod 66, 67, namely from top to bottom of the Belleville washers 68, 69, a flat washer 70, 71 and a barrel washer 72, 73 which bears down respectively on face 23 or on face 22 and the barrel 75, 76 of which partially engages in the corresponding bore 50, 53; made of a synthetic material, this barrel washer 72, 73 avoids metal-to-metal contact between the lag screw 64, 65 and the pad 6 and facilitates the desired clearance of the pad 6 relative to the cross member 4 as well as relative to the lag screws 60 , 61 which then behave as a whole integral with the cross-member 4.

 In a manner known in itself, the barrel washer 72, 73 closely follows the rod 66, 67 of the corresponding lag screw 60, 61 so that practically no relative radial displacement can occur.

 On the other hand, in a characteristic manner of the present invention, care is taken to preserve, when the pad occupies its aforementioned privileged position relative to the cross-member 4, a continuous annular clearance 74, 75 between on the one hand an external peripheral face 76, 77 , cylindrical of revolution around an axis coincident with that of the lag screw 60, 61, which delimits each barrel 75, 76 in the direction of a distance from this axis and on the other hand the inner peripheral face 52, 53 of the corresponding hole 50, 51; for this purpose, taking into account that the barrel washers 72, 73 are preferably chosen from the ranges available on the market and consequently have imposed dimensions, the diameter D 1 of the inner peripheral faces 52, 53 of the holes is chosen. 50, 51 so that it is appreciably greater, for example of the order of a few millimeters, than the imposed diameter D2 of the outer peripheral faces 76, 77 of the barrels 75, 76. The holes 50 and 51 may moreover result In addition, each barrel 75, 76 has axially an unreferenced length less than the thickness also unreferenced that the bearing has between its underside 8 and, respectively, the face 23 or the face 22 so that when the barrel washer 72, 73 rests down respectively on the face 23 or on the face 22, the barrel 74, 75 remains slightly recessed upward relative to the bottom face higher 8 of the pad 6 and, for instance, is flush with the transition between the inner peripheral face 52, 53 of the corresponding bore 50, 51 and the recess corresponding 56, 57.

 In addition, the holes 62, 63 of the sole 10 have a diameter for example equal to the diameter D1 of the faces 52, 53 of the holes 50, 51, that is to say much greater than the diameter D3 of the rods 66, 67 of the lag screws 60, 61.

 Thus, in the aforementioned privileged position of the bearing 6 relative to the cross-member 4, there is no direct contact, radially with reference to the axes 54, 55 of the holes 50, 51, between the bearing 6, on the one hand, and all integral formed by the cross member 4 and the lag screws 60, 61 as well as the barrel washers 72, 73 which they carry, on the other hand, so that by means of an elastic deformation of the sole 10 in shear, and a friction of the faces 23 and 22 of the pad 6 under the barrel washers 72, 73, possibly facilitated by an elastic compression of the sole 10, the pad 6 can move in any direction of its lower face 8 relative to the crosspiece 4, in fact parallel to the upper face 5 thereof, within the limits imposed by the difference between the diameters D2 and D1.

 To oppose such displacements an elastic resistance, in addition to that which the sole 10 may oppose to them, as well as to prevent such displacements, at their maximum amplitude, from resulting in contact between the barrels 75, 76 of the washers with barrel 72, 73 and the inner peripheral faces 52, 53 of the holes 50, 51, which would result in a recovery by the lag bolts 60, 61 of the shear forces appearing between the bearing 6 and the crosspiece 4 when passing trains, undesirable since depriving the mounting of the needle 2 and the counter-needle 3 on the crosspiece 4 of the desired flexibility, the means 83, mentioned above, are provided for elastic support of the pad 6 in the direction 24 and in both directions mutually reported 48 on the bearing stop 49, which is itself immobilized firmly relative to the cross 4.

 To this end, it is possible to envisage making the bearing stop 49 in a form integrated into the cross member 4, in particular when the latter is made of prestressed reinforced concrete, but it is preferred to detachably mount the bearing stop 49 on the face upper 5 of cross 4.

 A nonlimiting example of a bearing stop 49 attached integrally to the upper face 5 of the cross member 4 will now be described, with reference to FIGS. 7 to 10 as well as to FIG. 11.

 This bearing stop 49, for example made in the foundry in the form of a single piece and having a mean plane 78 with respect to which it is symmetrical, which is perpendicular to the upper face 5 of the cross member and with which the mean plane substantially coincides 7 of the pad 6 when the latter occupies the aforementioned privileged position, has a planar, machined lower face 79 which rests on the upper face 5 of the cross-member 4 by means of a sole 80 which has a generally flat shape , between a flat lower face 81 by which it is applied flat on the upper face 5 of the cross-member 4 and an upper face 82 parallel to this face 81 and on which the lower face 79 of the l bearing stop 49.

 Unlike the sole 10 chosen and dimensioned so as to give elasticity to the mounting of the bearing 6 on the cross-member 4, the sole 80 is chosen and dimensioned so as to behave rigidly in compression and in shear between its lower faces 81 and upper 82 , this elasticity of the sole 10 and this inelasticity of the sole 80 is understood naturally by reference to the normal conditions of use, and in particular with reference to the forces which the bearing 6 respectively undergoes and, by means of means 83 of support of the latter against the stop of the pad 49, the pad 49 itself, due to the forces undergone by the needle 2 and the counter-needle 3 when the trains pass. The sole 80 may possibly be produced in the same materials than the sole 10, but present between its faces 81 and 82 a thickness not referenced less than that, also not referenced, than the sole 10 between its faces Il and 12; the two soles 10 and 80 can also be made of different materials.

 The lower face 79 of the bearing stop 49 has a contour whose shape is indifferent, except in a localized manner as will emerge from the following description, and is connected along this contour to a edge 119 which la connects to an upper face 84 of the bearing stop 49; this upper face 84 is planar, machined, and parallel to the lower face 79.

 However, in a direction which coincides with direction 18 when the pad stop 49 and the pad 6, occupying said privileged position, are assembled to a cross member, the edge 119 extends, projecting upwards relative to the face. upper 84 of the bearing stopper 49, in the form of two flat edges 85 mutually symmetrical with respect to the mean plane 78 and oriented perpendicular to the lower faces 79 and upper 84 of the bearing stopper 49. These two edges 85 are mutually connected along the mean plane 78 while, in the direction of a distance from it, each of them is connected to a respective flange 86 of the bearing stop 49; like the flanges 85, each of the flanges 86 is projecting above the upper face 84 of the sliding pad 49, along the edge 119 thereof, and oriented perpendicular to this upper face 84 as well as to the underside 79 of the sliding pad 49, the two flanges 86 being flat and oriented parallel to the mean plane 78 with respect to which they are mutually symmetrical.

 In direction 18, if it is assumed that the bearing stop 49 and the bearing 6, occupying said privileged position, are mounted on the cross-member 4, the two flanges 85 have a respective planar, machined face 87 perpendicular to the underside 79 of the bearing stop 49.

 The two faces 87, which are connected mutually along the plane 78 by means of a transition facet 88 set back in the direction 24, on the same assumption of mounting the bearing stop 49 and the bearing 6 on a cross, are oriented obliquely to the mean plane 78, forming between them an angle ss equally distributed on either side of the plane 78 and equal to the difference between 360 "and the angle ci formed between them the faces abutment 46 of the cushion 6; in other words, in the nonlimiting example illustrated, each face 87 forms with respect to the plane 78 a 3/2 angle of 66 "+ 0.25.

 Thus, when the pad stop 49 and the pad 6, occupying said privileged position, are mounted on the cross-member 4 and the pad stop 49 is juxtaposed in the direction 24 with the pad 6, each of the faces 87 is placed in look of a respective abutment face 46 of the bearing 6, while being both spaced from this abutment face 46 and parallel to it, just as the transition facets 47 and 88 are mutually spaced so that Then there remains between the pad 6 and the pad stop 49 a continuous space 118.

 Each of the faces 87 of the bearing stop 49 however constitutes an abutment counterpart for the respectively corresponding abutment face 46 of the bearing 6 and, as such, is part of the means 83, cited above, for elastic bearing of the bearing 6 on bearing stop 49.

 For this purpose is interposed between each abutment face 46 of the bearing 6 and the respectively corresponding abutment face 87 of the bearing stop 49 a respective pad 89, elastically deformable in compression and in shear, in contact without prestressing with the faces of stop 46 and 87 respectively corresponding when the pad 6 occupies the aforementioned privileged position.

 More precisely, each pad 89, made of rubber or of synthetic material having the elasticity of the rubber, has two plane faces, mutually parallel, 90 and 91 mutually spaced apart with a thickness E substantially equal to the thickness separating each other from a abutment face 46 the corresponding abutment face 87, if we consider the pad 89 in the rest state and the pad 6 in its aforementioned privileged position, the faces 90 and 91 being placed respectively in contact, flat, with one of the abutment faces 46 and of the corresponding abutment face 87.

 These faces 90 and 91 are joined by a edge 92 which has any shape compatible with the generally rectangular shape of the abutment faces 46 and 87, namely in the illustrated example a form of revolution around an axis 93 perpendicular to the faces 90 and 91. More precisely, the edge 92 is formed of a cylindrical face 94 of revolution around the axis 93 and connecting to the face 91, and of a frustoconical face 95 of revolution around the axis 93 and connecting on the one hand to the face 94 and on the other hand to the face 90 while converging towards its connection with the face 90; each flat face 90, 91 of the pad 89 thus has a circular contour with a diameter D7, D8 at most equal to the diameter (not referenced) of a circle (not shown) inscribed in the respective corresponding abutment face 46, 87 of so as to ensure mutual contact flat above.

 Preferably, each of the buffers 89, which are identical and mutually symmetrical with respect to the plane 78, is secured with at least one of the corresponding abutment faces 46, 87 and, advantageously, it is thus secured only with one of them, namely in the example illustrated with the abutment face 87, that is to say with the corresponding flange 85 of the bearing stop 49.

 This attachment is preferably removable in order to authorize an easy change of the pads 89 in maintenance and, for this purpose, each of the pads 89 carries integrally, by making in one piece, a stud 96 projecting from the face 91 according to axis 93; this tenon 96, which is elastically compressible in particular radially with reference to the axis 93, is for example delimited in the direction of a distance from this axis by an outer peripheral face 97 of generally cylindrical shape of revolution around the axis 93 with a diameter D4 determined at rest, that is to say in particular in the absence of centripetal radial stress applied to the stud 96, and this outer peripheral face 97 is locally hollowed out by a number of rectilinear grooves 98 parallel to the 'axis 93; by way of nonlimiting example, eight grooves 98 have thus been illustrated, distributed in four identical groups of two identical grooves, these groups being mutually offset angularly by 90 "with reference to the axis 93 and the two grooves 98 by same group being mutually offset angularly by a few degrees with reference to this axis 93, but other arrangements could also be chosen without departing from the scope of the present invention. The tenon 96 is also delimited by a face end plane 99, which is perpendicular to the axis 93 and to which the outer peripheral face 97, connecting directly to the face 91, is connected by means of a frustoconical face 100 of revolution around the axis 93 and narrowing in a direction going from its connection with the external peripheral face 97 towards its connection with the end face 99.

In order to receive and retain the pin 96 of the corresponding pad 89, each of the flanges 85 is pierced right through, in a central zone of its abutment face 87, with a hole 101 essentially delimited by an inner peripheral face. 102 cylindrical of revolution around an axis 103 perpendicular to the face 87 considered, to which this inner peripheral face 102 cylindrical of revolution around the axis 3 is connected by a face 104 frustoconical of revolution around the axis 103 and s flaring towards the corresponding face 87. The inner peripheral face 102 cylindrical of revolution around the axis 103 has a diameter D5 slightly less than the diameter D4, the difference between these two diameters being easily determined by a
A person skilled in the art so that the engagement of the tenon 96 of a pad 89 in the corresponding hole 101, coincident with the axes 93 and 103, causes radial compression of the tenon 96 by its face 97 in contact with the face 102, and that this radial compression in the elastic range is sufficient to ensure the retention of the stud 89 on the corresponding flange 85.

 The pads 89 constitute, with the abutment faces 46 and 87, the means 83 for elastic bearing of the pad 6 on the pad stop 49 both in the direction 24 and in the mutually opposite directions 48 perpendicular to the mean plane 7 of the pad 6, due to the obliquity of the abutment faces 45, on the one hand, and of the abutment faces 87, on the other hand, relative to the mean plane 7 of the bearing 6 and relative to the mean plane 78 of the bearing stop 49, respectively.

 The pads 89 bearing on the abutment faces 87 of the pad stop 49 allow the pad 6 to move slightly in the direction 24 as well as in one or the other of the directions 48 under the effect of the forces applied. at needle 2 and against needle 3 when passing trains, and to ensure the return of bearing 6 to its aforementioned privileged position when these efforts cease.

 In this respect, the firm immobilization of the bearing stop 49 relative to the cross-member 4 allows this bearing stop 49 to serve as a positioning reference for the bearing 6.

 To this end, means 105 are provided for tightening the bearing stop 49 and the sole 80 on the upper face 5 of the cross member perpendicular to this upper face 5 as well as to the lower face 79 of the bearing stop. 49, the immobilization of the bearing stop 49 on the cross member preferably preferably resulting essentially from the tightening effect applied by these means 105 to the bearing stop 49 and to the sole 80 than by working these means 105 in shear.

 These clamping means 105 are advantageously of the same type as the clamping means 13, and comprise screwing members, namely essentially lag bolts 106, passing through the bearing stop 49 right through perpendicular to its underside 79 in order to be screw in corresponding holes, not referenced, of the cross member 4.

 To receive these lag bolts 106, here two in number, the bearing stop 49 is drilled right through, that is to say from its upper face 84 to its lower face 79, between the flanges 86 and so offset in direction 24 relative to the flange 85 if the bearing stop 49 mounted on a cross member is assumed as well as the bearing 6 occupying the aforementioned privileged position, two holes 108 having a shape of revolution about a respective axis 109 perpendicular to faces 84 and 79.

 Each of the holes 108 is essentially delimited by an inner peripheral face 110 of cylindrical revolution around the respective axis 109 with a diameter D6 determined with precision, in a manner which will be described later; for this purpose, the holes 108 are preferably produced by machining. This inner peripheral face 110 is connected to the lower face 79 of the bearing stop 49 by a recess 111 of revolution about the respective axis 109 while it is connected to the upper face 84 of the bearing stop 49 by a frustoconical face 111 of revolution about the respective axis 109 and widening towards the upper face 84 of the bearing stop 49.

 Each of the holes 108 thus arranged receives coaxially the rod 113 of a respective lag screw 106, which rod carries coaxially, between the head 120 of the lag screw 106 disposed above the upper face 84 of the bearing stop 49 and this upper face 84, a stack of washers comprising, from bottom to top, Belleville washers 114, a flat washer 115 and a barrel washer 116 which bears downwards on the upper face 84 of the bearing stop 49 around the bore 108 corresponding so as to transmit to the bearing stop 49 a clamping force on the upper face 5 of the cross-member 4 via the sole 80, this force being transmitted from the head of the lag bolt 106 by the intermediate stack of washers 114, 115; the barrel 121 of the barrel washer 116 is in turn engaged in the corresponding hole 108.

 The barrel washer 116, preferably identical to the barrel washers 72, 73, closely follows the rod 113 of the corresponding lag screw 106 in radial directions with reference to the corresponding axis 109 and, by the outer peripheral face 117 of its barrel 121 , cylindrical of revolution around the corresponding axis 109, comes into contact on all sides, practically without play, with the inner peripheral face 110 of the respective bore 108 so as to allow practically no radial clearance, with reference to axes 109, between the bearing stop 49, on the one hand, and the assembly then integral formed by the lag bolts 106 and the crosspiece 4. For this purpose, the aforementioned diameter D6 is substantially equal to the diameter D2 of the outer peripheral face 117 of the barrel washer 116. In addition, the barrel of each barrel washer 116 is dimensioned so that, parallel to the respective axis 109, its length is less than the thickness issuer separating the lower 79 and upper 84 faces of the bearing stopper 49 mutually, so that it is permanently set back upwards with respect to the lower face 79 of the bearing stopper 49 and does not risk thus not to oppose the tightening of the latter on the crosspiece; for example, thanks to an appropriate dimensioning, the barrel 121 of each barrel washer 116 follows the entirety of the inner peripheral face 110 of the corresponding hole 108, that is to say ends at the transition between this inner peripheral face 110 and the recess 111.

 Naturally, this method of mounting integral with the bearing stop 49 on the crosspiece 4 is only a non-limiting example with respect to which many variants can be provided, as well as with regard to the floating mounting of the bearing 6 relative to the cross member 4. The means 83 for elastic bearing of the pad 6 against the pad stop 49, constituted in the example illustrated by the two abutment faces 46 of the pad 6, the two buffers 89 and the two faces stop 87 of the bearing stop 49, can vary considerably without departing from the scope of the present invention; in particular, instead of providing that the abutment faces 45 of the bearing 6 define a dihedral angle a greater than 1800 while the abutment faces 87 of the bearing stop 49 form a dihedral angle ss less than 1800 , to have a general shape respectively convex and concave, it may be the pad stop 49 which has abutment faces defining a convex shape and the pad 6 which has abutment faces defining a concave shape.

 In general, a person skilled in the art will readily understand that the mode of implementation of the invention which has just been described constitutes only a non-limiting example, with respect to which many variants can be provided without thereby departing from the part of the present invention.

Claims (31)

 1. Device intended for mounting a needle (2) and a mutually associated counter-needle (3) on a cross-member (4), in particular a cross-member (4) of prestressed reinforced concrete, and comprising for this purpose a bearing sliding (6) having a mean plane (7), a face (8) of bearing of the bearing (6) on a face (5) of the cross-member (4), the face (8) of bearing of the bearing ( 6) being planar and cutting perpendicularly the mean plane (7) of the bearing (6) by defining with it a preferred direction (9), means (17, 19, 25) for receiving a counter-needle (3) and a needle (2) on the pad (6) opposite the bearing face (8) of the pad (6), respectively at a location determined with respect to the pad (6) and at a location that is variable by relative to the bearing (6) and juxtaposed at the determined location of the counter-needle (3) in a determined direction (18) of said preferred direction (9), as well as means (10, 13) for mounting the cushion net (6) on the crosspiece (4),  characterized in that the means (10, 13) for mounting the bearing (6) are chosen and / or tolerated so as to allow limited movement of the bearing (6) relative to the crosspiece (4) in all directions of the support face (8) of the cushion (6) from a privileged position of the cushion (6) relative to the cross-member (5), in that the device (1) further comprises a stop (49) for bearing (6) having a mean plane (78), means (80, 105) for immobilizing the stop (49) of bearing (6) relatively to the crosspiece (5) in a position in which the the pad stop (49) is juxtaposed with the pad (6) in the direction (24) opposite to said determined direction (18) and the mean planes (7, 78) of the pad (9) occupying said privileged position and of the 'stop (49) of the bearing (6) substantially coincide, and in that the stop (49) of the bearing (6) and the bearing (6) have support means (83) towards each other elastic neck ssinet (6) against the stop (49) of the bearing (6) in said opposite direction (24) and in two directions (48) perpendicular to the mean plane (7) of the bearing (6) and mutually opposite, from said privileged position.  2. Device according to claim 1, characterized in that the cushion (6) and the stop (49) of the cushion (6) are respectively symmetrical with respect to the corresponding mean plane (7, 78), in particular as regards said means (83 ) elastic support.  3. Device according to any one of claims 1 and 2, characterized in that said means (83) of elastic support comprise  - on the bearing (6) two substantially flat abutment faces (45) substantially perpendicular to the bearing face (8) of the bearing (6) and disposed respectively on either side of the mean plane (7) of the bearing ( 6) by forming between them a dihedral of determined angle (a) different from 1800,  - On the stop (49) of the bearing (6) two abutment faces (87) substantially flat and disposed respectively on either side of the mean plane (78) of the stop (49) of the bearing (6) in forming between them a dihedral of angle (ss) determined so that each abutment face (87) of the bearing stop (49) of the bearing (6) is placed opposite a respective abutment face (46) of the bearing (6) occupying said privileged position, being parallel to this abutment face (46) and respecting a continuous space (118) relative to it,  - between each abutment face (87) of the bearing (49) of the bearing (6) and the respective abutment face (46) of the bearing (6) and in engagement with each of them, a buffer (89) elastically deformable in compression and shear.  4. Device according to claim 3, characterized in that the abutment faces (87) of the bearing stop (49) form between them a concave dihedral (ss) and the abutment faces (46) of the bearing (6) form between them a convex angle dihedral (a).  5. Device according to any one of claims 3 and 4, characterized in that each pad (89) is integral with one (87), at least, of the abutment faces (46, 87) corresponding.  6. Device according to claim 5, characterized in that each buffer (89) and one (87), at least, of the abutment faces (46, 87) corresponding comprise means (96, 101) of removable mutual securing .  7. Device according to claim 6, characterized in that the means (96, 101) for removably securing a buffer (89) with at least one (87) of the abutment faces (46, 87) comprise at least one hole (101) arranged in this abutment face (87) and a respective resiliently compressible lug (96) integral with the pad (89), engaged in this hole and dimensioned so that it is retained therein. elastic compression preload.  8. Device according to any one of claims 5 to 7, characterized in that each pad (89) is secured to the corresponding abutment face (87) of the stop (49) of the bearing (6).  9. Device according to any one of claims 1 to 8, characterized in that the stop (49) of the bearing (6) has a face (79) bearing on said face (5) of the crosspiece (4) , this face (79) bearing the stop (49) of the bearing (6) being plane and perpendicular to the mean plane (78) of the stop (49) of the bearing (6), and in that the means (80, 105) for immobilizing the bearing stop (49) (6) relatively to the cross-member (4) are means (80, 105) for mounting the bearing stop (49) (6 ) on the crosspiece (8), chosen and / or tolerated so as to ensure said firm immobilization.  10. Device according to claim 9, characterized in that the means (80, 105) for mounting the stop (49) of the bearing (6) comprise a sole (80) rigid in compression and in shear, interposed between the face bearing (79) of the bearing (49) of the bearing (6) and said face (5) of the crosspiece (4), and means (105) for tightening the bearing (49) of the bearing (6) on said face (5) of the crosspiece (4) perpendicular to the bearing face (79) of the stop (49) of the bearing (6).  11. Device according to claim 10, characterized in that the means (105) for tightening the bearing stop on said face (5) of the crosspiece (4) comprise holes (108) passing through the stop (49) of bearing (6) perpendicular to its bearing face (79) and members (106) for screwing the stop (49) of bearing (6) on the crosspiece (5), through said holes (108), said holes (108) being dimensioned so that there remains practically no play around each screw member (106).  12. Device according to any one of claims 1 to 11, characterized in that the means (10, 13) for mounting the bearing (6) comprise a sole (10) elastically deformable in compression and in shear, interposed between the face bearing (8) of the bushing and said face (5) of cross-member (4), and means (13) for clamping the bushing (6) on said face (5) of cross-member (4) perpendicular to the face of support (8) of the bearing (6).  13. Device according to claim 12, characterized in that the means (13) for clamping the pad on the crosspiece have holes (50, 51) passing through the pad (6) perpendicular to its bearing face (8) and members (60, 61) for screwing the bearing (6) on the cross-member (5), through said holes (50, 51), said holes (50, 51) being dimensioned so that they remain around each screw member (60, 61) a continuous play (74, 75) in said privileged position of the bearing (6).  14. Sliding bearing intended for mounting a needle (2) and a mutually associated counter-needle (3) on a cross-member (4), in particular a cross-member (4) made of prestressed reinforced concrete, said bearing (6) having a mean plane (7), one face (8) of bearing of the bearing (6) on one face (5) of the cross-member (4), the face (8) of bearing of the bearing (6) being plane and perpendicularly cutting the mean plane (7) of the bearing (6) by defining with it a preferred direction (9), means (17, 19, 25) for receiving a counter-needle (3) and a needle ( 2) on the pad (6) opposite the bearing face (8) of the pad (6), respectively at a determined location relative to the pad (6) and at a variable location relative to the pad (6 ) and juxtaposed at the determined location of the counter-needle (3) in a determined direction (18) of said preferred direction (9), as well as means (10, 13) for mounting the bearing (6) on the cross-member (4),  characterized in that the means (10, 13) for mounting the bearing (6) are chosen and / or tolerated so as to allow limited movement of the bearing (6) relative to the crosspiece (4) in all directions of the support face (8) of the bearing (6) from a privileged position of the bearing (6) relative to the cross-member (5), and in that the bearing (6) has means (46) for support against a stop (49) of the bearing (6) in the direction (24) opposite to said determined direction (18) and in two directions (48) perpendicular to the mean plane (7) of the bearing (6) and mutually opposite, from said privileged position.  15. A bearing according to claim 14, characterized in that it is symmetrical with respect to the mean plane (7), in particular as regards said support means (46).  16. A bearing according to any one of claims 14 and 15, characterized in that said support means (46) comprise two abutment faces (46) substantially planar, substantially perpendicular to the bearing face (8) of the bearing (6) and disposed respectively on either side of the mean plane (7) of the bearing (6), forming between them a dihedral of determined angle (ci) different from 1800.  17. A bearing according to claim 16, characterized in that the abutment faces (46) form between them a dihedral of angle (a) convex.  18. A bearing according to any one of claims 16 and 17, characterized in that it comprises two buffers (89) elastically deformable in compression and in shear, each of which is secured to a respective abutment face (46).  19. Pad according to any one of claims 14 to 18, characterized in that the means (10, 13) for mounting the pad (6) comprise a sole (10) elastically deformable in compression and in shear, interposed between the face bearing (8) of the bushing and said face (5) of cross-member (4), and means (13) for clamping the bushing (6) on said face (5) of cross-member (4) perpendicular to the face of support (8) of the bearing (6).  20. A bushing according to claim 19, characterized in that the means (13) for clamping the bushing on the crosspiece have holes (50, 51) passing through the bushing (6) perpendicular to its bearing face (8) and members (60, 61) for screwing the bearing (6) on the cross-member (5), through said holes (50, 51), said holes (50, 51) being dimensioned so that they remain around each screw member (60, 61) a continuous play (74, 75) in said privileged position of the bearing (6).  21. Stop for a sliding bearing (6) intended for mounting a needle (2) and a counter-needle (3) mutually associated on a cross member (4), in particular a cross member (4) made of prestressed reinforced concrete ,  characterized in that it has a mean plane (78), means (80, 105) for immobilizing the stop (49) of the bearing (6) relatively to the crosspiece (5), and means ( 87) for supporting the bearing (6) in one direction (24) of the mean plane (78) and in two directions (48) perpendicular to this mean plane (78) and mutually opposite.  22. Cushion stop according to claim 21, characterized in that it is symmetrical with respect to the mean plane (78), in particular as regards said support means (87).  23. bearing stop according to any one of claims 21 and 22, characterized in that said support means (87) comprise two abutment faces (87) substantially planar and disposed respectively on either side of the mean plane (78) by forming between them a determined dihedral (B).  24. cushion stop according to claim 23, characterized in that the abutment faces (87) of the cushion stop (49) form between them a concave dihedral (ss).  25. bearing stop according to any one of claims 23 and 24, characterized in that each abutment face (87) comprises means (96, 101) of removable mutual securing for a respective pad (89) elastically deformable in compression and in assault.  26. bearing stop according to claim 25, characterized in that the means (96, 101) for removably securing a pad (89) with one (87), respectively, abutment faces (87) comprise at at least one hole (101) arranged in this abutment face (87) to receive a respective elastically compressible tenon (96) integral with the pad (89), dimensioned so that it is retained in elastic compression preload in the hole.  27. bearing stop according to any one of claims 23 to 26, characterized in that it comprises two buffers (89) elastically deformable in compression and in shear each of which is secured with a corresponding abutment face (87) of the 'stop (49) of bearing (6).  28. bearing stop according to any one of claims 21 to 27, characterized in that it has a face (79) bearing on a face (5) of the crosspiece (4), this face (79) d support of the bearing stop (49) (6) being plane and perpendicular to the mean plane (78) of the bearing stop (49) (6), and in that the means (80, 105) of firm immobilization of the bearing stop (49) (6) relative to the cross member (4) are means (80, 105) for mounting the bearing stop (49) of the bearing (6) on the cross member (8) , chosen and / or tolerated so as to ensure said fixed asset.  29. bearing stopper according to claim 28, characterized in that the means (80, 105) for mounting the stopper (49) bearing (6) comprise a sole (80) rigid in compression and shear, interposed between the bearing face (79) of the bearing stop (49) (6) and said face (5) of cross-member (4), and means (105) for tightening the bearing stop (49) ( 6) on said face (5) of the crosspiece (4) perpendicular to the bearing face (79) of the stop (49) of the bearing (6).  30. Bushing stopper according to claim 29, characterized in that the means (105) for tightening the bushing stopper on said face (5) of the crosspiece (4) comprise holes (108) passing through the stopper (49 ) of the bearing (6) perpendicular to its bearing face (79) and of the members (106) for screwing the stop (49) of the bearing (6) on the cross-member (5), through the said bores (108) , said holes (108) being dimensioned so that there remains practically no play around each screw member (106).  31. bearing stop according to any one of claims 28 to 30 in combination with any one of claims 23 to 27, characterized in that the abutment faces (87) are perpendicular to the bearing face (79) on the face (5) of the crosspiece (6).