FR2873963A1 - Adjustment arm for continuous angular orientation device, has helical ribs counter-supported on central rod, for blocking axial displacement of arms and neutralizing clearance obtained during release of arms and thrust of screw on one arm - Google Patents

Abstract

The arm has a tube with helical grooves and in which helical ribs (12) of arms (20, 21) are counter-supported on a central rod, for blocking axial displacement of the arms (20, 21) and neutralizing a clearance due to tilting of an energy absorption device. The clearance is obtained during the release of the arms (20, 21) and a correlative thrust of a screw (23) on one of the arms to ensure the unblocking of the displacement.

Description

The present invention relates to a safety device for seats of

  motor vehicles, particularly in the event of accidental shock, by progressive absorption of programmable energy associated with a mechanism for trimming and maintaining angular position of the seat and the backrest, as described in French patents N 00.02762,

  "Motor vehicle seat joint adjustment mechanism", N 00.10313, "Motor vehicle seat articulation device" and PCT / FR01 / 00611, "Motor vehicle seat adapted to receive a seat belt" , in the name of the same inventor.

  These mechanisms comprise a transverse tube mounted horizontally and secured to two frame elements of the seat, such as, for example, the amounts of the backrest, the ends of this tube, protruding from these amounts, coming to engage in bearing bearings in rotation integral with the seat sides of the seat and thus forming the axis of articulation of the inclination of the backrest, the tube comprising at least one, but preferably several, internal helical grooves in which comes to fit, free translation axial but guided in angular setting by these helical grooves, a trimming nut having on its outer surface corresponding helical ribs and traversed on the one hand axially by a central bar provided with straight splines and interlocked in a corresponding hole blocking any rotational movement between the nut and the bar, but not the sliding of the nut on the bar along their common axis, the e the ends of the bar being held by the bearings integral with the seat flanks, at least one of its extremities being locked in rotation, the trimming nut being, on the other hand, traversed by a threaded hole parallel to, but radially offset from the bar and receiving a screw free in rotation but wedged in translation on at least one of the bearings, the control in rotation of this screw by at least one of its extremities protruding from the bearing ensuring the axial displacement of the nut which, locked in rotation on the bar, will cause the rotation of the tube by action on its helical grooves, and thus the variation of inclination of the backrest.

  This design advantageously allows, in the case of a belt mounted on the seat and requesting a single amount of backrest, to absorb the force by a single half of the tube, while the torsion bar works equally on its two ends.

  The force exerted on the backrest in the event of an accident, being supported in its entirety by the amount receiving the belt anchorage, will be applied, whatever its distribution, at each end of the tube and integrally transmitted by the tube. the nut which retransmits itself to the central bar then acting as a torsion bar which distributes it proportionally to each of its ends according to the axial position of the nut.

  In the opposite case of the tube supported by the flanks of the seat and the torsion bar by the backrest, it would be the tube, usually more resistant, which would work on both ends, while the torsion bar, which is weaker, would only work on one half, which would lead to oversizing to absorb the planned effort.

  Shock absorbing devices related to the seats of the occupants of a vehicle are, depending on the safety standards to be complied with, the structure, the type of vehicle and the results of the impact tests established during their development, designed specifically for each type of vehicle. One of the objects of the present invention is a device making it possible, from a standard unit of seat inclination trimming mechanism mentioned above, to obtain a progressive progressive damping as a function of the evolution of the forces undergone and allowing self-adaptation. instantaneous and automatic energy absorptions desired for these mechanisms according to the situations envisaged for different types of vehicles.

  According to the invention, the central bar, in addition to its role of guiding and setting the trimming nut of the reclining control mechanism of the seat back, will have a function of energy absorption bar comprising at least a zone of plasticization with progressive stiffness, by variation of the section of metal concerned, for solid or hollow bars, preferably of tubular form, or the thickness of a surface hardening. In the case of a single zone, this plastification zone may be preferably located on an appropriate axial length at the blocked end of the bar. The progressivity of its stiffness may result from a gradual increase in the tubular thickness, resulting for example from a frustoconical bore of this part of the tubular bar or from a surface hardening with progressively variable depth.

  The zone of plasticization of the bar will comprise on its external surface at least one rib in relief parallel to its axis. This rib will be supported on a series of support points arranged on the inner surface of a sleeve concentric to the bar, covering the plastic zone and secured to the bar beyond this area. These support points may be advantageously formed by at least one helical ramp against which abuts the rib of the plasticizing zone, thus forming an evolutive continuous support point depending on the plastic deformation in torsion of the plasticizing zone. This arrangement thus ensures a regular and programmed twisting of the plastic deformation zone by winding around the bearing ramps of the outer sleeve and thus a displacement of the twisting bearing point towards the zones with progressive increase of the stiffness as a function of the loads. transmitted and therefore a gradual absorption of efforts. This avoids a local concentration of deformation resulting in a necking of the bar by exceeding a certain torsional stress threshold and each load will be automatically opposed a corresponding damping.

  This trimming sleeve of the progressive increase in the stiffness of the lamination zone will advantageously be secured to the central bar by interlocking with force on the splines arranged on the outer surface of the bar and guiding the trimming nut. inclination of the seat back as well as its end-of-travel limitation. The resistance of the sleeve will complete the resistance of the zone of plasticization to obtain a resistance always at least equal to that of the bar which it prolongs, ensuring the complement of the zone of plasticization starting from its progressive point of support and serving as limit stop at the trimming nut.

  The helical ramps of the progressivity trimming sleeve are calculated to determine the maximum angle of rotation of the backrest, ie, for example 50, which is thus limited in the end stop but with a progressive deceleration up to this value without stopping. brutal in case of shock before. For the rear shocks, in the opposite direction of rotation, counter-support ramps bear against the opposite sides of the ribs. In this case, these helical ramps are calculated for a different angle, for example 15 to 20, corresponding to this function.

  A torsion limitation of the zones of plasticization can also be obtained, according to the invention, by realizing the trimming sleeve in two parts nested between them by a jaw assembly having a play in rotation corresponding to the desired plasticization deformation limits, by example of 50 in front damping and 20 in rear damping. The jaw assembly could be of the open type, the jaw clutching in the thickness of the sleeve, or of the closed type, the interlocking taking place radially in cavities of an extra thickness in which fit with play in rotation the two ends of assembly of the sleeve. This solution, which is not progressive and causes a sudden stop, can be used as a limit limiter.

  To ensure a good accuracy of the amounts of energy absorption provided by the device according to the invention, without depending on the construction tolerances of the mechanisms, the seat structure and the vehicle and external circumstances, it is at the same time, at the level of the external helical ribs which receive the force transmitted by the tube and at the level of the internal straight splines transmit directly to the central bar, and therefore to its energy absorbing device.

  For this purpose, according to the invention, a coupling of two nuts, slidably free with respect to each other in a limited spacing and angularly immobilized by the central energy absorption bar, is used. Their axial displacement in opposition by spacing or approximation under the thrust of a nut actuated by the adjusting screw causes each to drive the tube in an opposite direction and thus immobilize it angularly with respect to the central bar. The helical grooves of the tube on which the nuts come to bear in an opposite way force them to be against the support of the splines of the central bar, which blocks the axial displacement of the two nuts and causes the jamming of the entire mechanism and consequently the neutralization of the tilting of the backrest by jamming at rest obtained by the coupling of the two nuts. The clearance necessary for the operation of the reclining mechanism of the backrest angle will be obtained automatically when the two nuts are unhooked by the control of the screw for adjusting the position of the backrest and the corresponding thrust of the nut on one of the nuts assuring his unlock.

  In the case of jamming obtained by bringing the two nuts together, they are in operation in maximum spacing position as if it were a single nut with continuous helical ribs and which would have removed the central portion . The space between the two nuts must be sufficient to allow jamming, without they are in contact at rest, under the action of the pressure of a spring bringing the two nuts together. In order to avoid a gap lock, a retaining screw will limit the maximum spacing of the two nuts so that their helical ribs are in line with one another as if they formed a single unbroken rib. The unlocking by spacing of the two nuts will be done automatically during any trimming position of the folder, resulting in a drive nut towing the other. The back tilt adjustment control screw drives a free nut axially but immobilized angularly by the nuts which abuts in the nut concerned in the direction of rotation of the control screw.

  In the case of jamming obtained by spacing the two nuts, the operating principle will be identical, but inverted. The control of the "drive" nut will cause a reconciliation unlocking the mechanism by the action of nuts located on the opposite faces of the nuts against a spacer spring located between the nuts. This solution is a little more complex than the previous one by requiring two nuts and their spacing adjustment, on the other hand, screws for retaining the spacing of the nuts are not necessary, this distance being limited by the jamming and unlocking being ensured. by the bringing together of the nuts one of the other, this approximation being limited by the setting in support of the two nuts one safe of the other.

  By these devices are thus neutralized the games both on the side of the central bar and the helical grooves, allowing to no longer be dependent on the dimensions of construction and their tolerances. Moreover, the combination of two smaller nuts each than a single nut promotes their realization in sintered material, especially steel, high density and increases the total length and therefore the contact surface on the side of the helical ribs about 50%.

  The movable end of the torsion bar, opposite the fixed end, may be used, depending on its degree of torsion as a result of a variation of uncontrolled inclination of the seat back in case of accident, to automatically trigger an articulated seat of the seat, called "anti-submarining", raising the seat by a mechanical means such as a spring joint and thus preventing the sliding of the occupant along the seat forwards, and / or a pretensioning belt, tilting device before the headrest or the upper part of the backrest or simultaneously of both if they are one, in the event of a rear impact and all other auxiliary functions of protection against front or rear impact.

  For this purpose, an insert will be fixed on the end of the torsion bar, limiting in rotation the angular displacement of the bar about 5 forwards and backwards, this part being provided with a trigger arm will be driven in rotation in the bearing under the action of the shock that triggered the rotation of the torsion bar, ensuring the triggering of the auxiliary protection devices it has the function to activate.

  The bearings of the device according to the invention simultaneously provide the functions of fixing and articulation of the backrest on the seat cushion and the fixing of the energy absorption bar connected to the seat, one of its extremmites being fixed, preferably welded to one of the bearings, the other bearing receiving the other end of the bar with a set of predetermined angular rotation. They also contribute to maintaining the spacing and verticality of the flanks of the seat cushion and incorporate a control mechanism for rapid positioning of the inclination of the backrest, concentric of the continuous tilting trimming mechanism prenentioned.

  These bearings are centered on the spacer tube containing the mechanism according to the invention and made integral with its ends. They are thus centered on the axis of rotation of the file. Made of stamped sheet metal, they have flanges for fixing on the sides of the seat base on which they are fixed by two screws in the upper part of the seat. A third screw will be added in the lower part at the end of a prolongation of maximum elongation downward of the fixing flange of the bearing. Given the very significant efforts exerted on the bearings in the case of safety belts retained by the backrest, this provision will reduce the forces exerted by the bearings on the flanks of the seat base. The screw located in the lower part to receive the anchoring of the seat belt can also be used to serve as a third fixing point of the bearing flange, with a corresponding simplification of the assembly and a corresponding reduction in cost. The flange of the bearing will then be wedged between the surface of the seat and the attachment plate of the belt, thus forming a rigid and resistant stack.

  The mechanism according to the invention also makes it possible to receive, by fixing in the middle of the spacer tube, seat backs with a single axial column, telescopically height-adjustable and surmounted by a headrest frame receiving the upper attachment of seat belt. This column then has the advantage of transmitting the forces directly at the level of the trimming nut. Such a structure, in addition to its weight reduction compared to the classic frameworks of files, has the advantage of leaving any freedom of design of the file to which it applies. The space on either side of the column can be left free, which increases the space available at the rear of the seat.

  Eccentric rings will be reported on the ends of the tube to allow a refocusing of the central bar and therefore the mechanism to eliminate any jamming or deformation resulting from an accident having twisted the areas of plasticization, which can change the alignment of the bar and result in misalignment called "bayonet setting" areas of plasticization and hardening of the operation.

  The two bearings thus constituted make it possible to integrate concentric mechanisms for rapid positioning of the backrest by successive offsets of discontinuous positions by means of a retractable catch for locking a rotating part of the bearing by blocking positioning notches, in a provision preventing the ratchet from coming out of its notch in the event of an accident by means of a permanent locking of the pawl in its notches only unlocked automatically during the commands of change of inclination of the backrest.

  The mechanism according to the invention can thus be produced as a complete autonomous mechanical subassembly, providing all the functions of control of seat adjustment, continuously or discontinuously, damping of the front and rear shocks, the assembly of the backrest on the seat. 'Seat and constitution of the seat in an autonomous unit with its seat belt, requiring no electrical connection for the control of systems of "anti-submarining" and / or pre-tensioner belt unit ready to be vehicle mounted.

  An exemplary embodiment of such a safety device for a motor vehicle seat according to the invention, in particular progressive energy absorption programmable for the implementation of different protections depending on the circumstances will be described below with reference to attached drawings where: - Figure 1 shows schematically an embodiment of the entire mechanism, in axial section; Figure 2 shows a cross-section at the trimming nut showing sections of the helical ribs and grooves and the distributions of their assembly sets; - Figure 3 shows in axial section the plasticization zone ensuring energy absorption at the fixed end of the central bar; - Figure 4 shows in axial section the end of the central bar section variable stiffness and the distribution of its twisting bearing ramps in folded section; - Figure 5 shows in axial section and folded section the twisting control tube and its helical ramps of limitation of plasticization deformation; - Figure 6 shows an axial section of an example of a twisting control tube comprising an angular limitation device of twisting; FIG. 7 represents in perspective and axial section the angular thrust jaws of rotation of the same device for angular limitation of twisting; - Figure 8 shows in perspective and axial section of an embodiment of the jaw, arranged radially in an excess thickness of the control tube; - Figure 9 shows in a cross section of the mechanism at the trimming nut the axial distribution of the elements of a walnut in two parts; - Figure 10 shows in axial section a two-part nut wedged by approximation under the action of a spring; - Figure 11 shows in axial section a two-part nut wedged by spacing under the action of a spring; FIG. 12 shows in axial section the free end of the torsion bar with an insert fixed on between the bar and the bearing, limiting in rotation the angular displacement of the bar and provided with a trigger arm of auxiliary devices of FIG. protection; - Figure 13 shows in perspective the assembly part between the bar and the bearing of this insert; FIG. 13-1 shows, in axial section of the end of a bar, an alternative embodiment of the mechanism in which the energy absorption bar has the same axis as the transverse tube, eliminating any risk of accidental blocking; - Figure 13-2 shows a corresponding cross-section at the connection to a file post; - Figure 14 shows a mounting assembly of the mechanism to the side of the seat cushion and the reinforcing extension of the fixing flange; - Figure 15 shows the same bearing in axial section along XV-XV; - Figure 15-1 shows schematically a telescopic single column seatback frame integral with the middle of the spacer tube, at the level of the trimming nut, with axial folded section showing the height adjustment rack of the column and view of above showing the location of a file shell; FIG. 15-2 shows an assembly bearing according to FIGS. 14 and 15 mounted on a seat shell flank with attached shell, for example of light alloy, with stiffening ribs and fallen edges ensuring its rigidity; FIG. 16 shows the ratchet face of a discontinuous ratchet backrest orientation device and a stored positioning cam mounted on a bearing in the forward tilt position of the backrest; - Figure 17 shows an axial section of the bearing provided with this device; - Figure 18 shows the same ratchet device according to Figure 16 in normal reclining position of the backrest, -25 tilt, with ratchet in the engaged position; - Figure 19 shows the opposite side of discontinuous file orientation device according to Figures 16, 17, 18, with its control system cable, latch and rudder; - Figure 20 shows the same device according to Figure 19 where the rudder, driven by the latch, in turn drives the pawl; - Figure 21 shows in perspective the entire mechanism according to the invention, the bearings are equipped with discontinuous orientation devices according to Figures 16 to 20; - Figure 22 shows in perspective, on a larger scale, the previous mechanism, with a section of the spacer tube showing the arrangement of the central bar, the control screw and its internal grooves guiding the nut.

  In FIG. 1, the tube 1, provided with helical internal grooves 2 over at least a part of its length, preferably obtained by a cold hammering technique ensuring precise shaping without further machining, is made integral with the base. two uprights 3 and 4 of a motor vehicle seat back, not shown, for example by welding. A trimming nut 5, having on its outer surface helical ribs 6 slidable in the internal helical grooves 2 of the tube 1, is slidably mounted on a bar 7 along the grooves 8 ensuring its locking in rotation. The ends of the bar 7 are engaged tightly in bearing bearings 9 and 10 integral with the sides of the seat cushion, not shown. A trimming screw 11 passes through a threaded hole corresponding to the nut 5 and is mounted fixed in translation and free to rotate in at least one of the bearing bearings, 9 for example, its end projecting beyond this bearing being provided with a socket operating mechanism such as a square allowing the control in rotation of the screw 11.

  A single screw 7a fixed axially at the end of the central bar 7 ensures the assembly of the mechanism inside the tube 1 and simultaneously the fixing of the bearing 10 and the arm 26 actuating the trigger functions. The tube 1 is engaged by the outside of the backrest in the upright 3 and then slid into the first face of the upright 4 and then into the second face, allowing, by polygonal indexing of triangular shape, to give it its angular position relative to the helical grooves of the tube 1.

  The rotation of the screw 11 causes the displacement in translation of the nut 5 along the axis of the bar 7 on which it slides and which maintains it in fixed angular position due to its rigidity and its mounting locked in rotation in at least, for example, the bearing 9 integral with the seat flank. As a result, the correlative displacement of the helical ribs 6 of the nut 5 will cause, by action on the helical internal grooves 2, a corresponding rotation of the tube 1 and thus the amounts 3 and 4 of the seat back. The important step chosen for the helical grooves 2 and the reduction in displacement of the nut 5 by the screw 11 will allow an angular trimming of the continuous file, linear and very precise, with a minimum of effort to exert on the control handle. Its control by simple rotation of the control socket makes it easy to adapt it to known electrical control devices for trimming seats.

  As it appears in FIG. 1, the mechanical sub-assembly consisting of the tubel connecting the uprights 3 and 4 of the backrest will be easily fitted into the upright 3, then slid to the upright 4 and oriented in this upright, for example by a triangle, to give the file its angular indexing of -25 relative to the vertical, shoulders for its axial positioning, and thus to precisely adjust the spacing of the uprights 3 and 4.

  The trimming and energy absorption mechanism is a ready-to-assemble subassembly. It comprises the bar 7 on which the bearing 9 is pressed into the press and welded, the control screw 11 assembled on the bearing and held axially by its two hemispherical stops 31, the nut 5 being mounted on the bar 7 and engaged on the screw 11, then brought for example to the middle of the bar 7. This subassembly will be placed in the tube 1 and held axially by the bearing 10, itself immobilized axially by the screw 7a assembly cooperating with a tapping made axially in the movable end of the bar 7.

  FIG. 2 shows on an enlarged scale a cross section of the mechanism at the level of the adjusting nut 5. In order to reduce the forces on the control screw 11, the flanks of the ribs 6 and grooves 2 will be substantially parallel to their axial plane to reduce the pressure angle as much as possible. Similarly, in the example described, to reduce friction, only three ribs 12, 120, shown in grid hatching on the nine shown, will be provided with a normal play of operation. The other six ribs will be slightly smaller and lower, so as not to wear in normal operation. They will come into contact only in case of accidental operation, to strengthen the strength of the assembly.

  FIG. 3 shows the arrangement of the central bar 7 in its energy absorption bar function according to the invention, its end, here of tubular shape, being secured to the bearing 9 by interlocking and welding and comprising a plasticizing zone. 13 to progressive stiffness, by variation of the metal section concerned, or the progressively variable thickness of a surface hardening 14. The progressiveness of its stiffness will result from a gradual increase in the tubular thickness, for example by means of a frustoconical bore of this portion 13 of the tubular bar, as shown in FIG. 4, or of a surface hardening with progressively variable depth as represented at 14. The plasticizing zone 13 of the bar will comprise on its outer surface at least one rib 15 raised parallel to its axis. The flank15-1 of this rib will be supported on a series of support points arranged on the inner surface of a sleeve 16 concentric to the bar, covering the plasticizing zone 13 and secured to the bar beyond this zone. These support points may advantageously be formed by at least one helical support ramp 17-1 against which abuts the flank 15-1 of the rib 15 of the plasticizing zone 13, thus forming a continuous continuous support point depending on the plastic deformation in torsion of the zone of plasticization. This arrangement thus provides a regular twisting of the plastic deformation zone by winding around the bearing ramps 17-1 of the outer sleeve 16 and thus a displacement of the twisting bearing point towards the areas with progressive increase of the stiffness in function transmitted charges and therefore an automatic absorption of the efforts according to their aggravation.

  The helical ribs 17-1 of the progressivity adjusting sleeve 16 are calculated to determine the maximum angle of rotation of the backrest, ie, for example 50, which is therefore limited at the end stop but with a progressive deceleration up to to reach this value without sudden stop in case of impact before. For the rear shocks, in the opposite direction of rotation, the flanks 15-2 of the ribs 15 abut on the flanks 17-2 helical ramps against support. In this case, the helical shape of the ramps is calculated for a different angle, for example 15 to 20, corresponding to this function.

  The trimming sleeve 16 of the gradual increase of the stiffness of the zone of plasticization will advantageously be secured to the central bar 7 by interlocking with force 18 on the grooves 8 arranged on the outer surface of the bar and ensuring the guiding of the 5 seat tilt trimming nut. The resistance of the sleeve 16 will complete the resistance of the progressive plasticizing zone to obtain a resistance at least equal to that of the bar 7 which it extends, providing the complement of relay with the zone of plasticization 13 from its point of contact. progressive support along the ribs 15 resting on the support ramps 17.

  FIG. 4 shows in axial section and section a bar end 7 whose progressive torsional damping stiffness at 13 is obtained by a frustoconical portion of its internal bore. The folded section shows the disposition of the torsion winding ribs 15 on the flanks of the helical ramps 17 of the sleeve 16 shown in the same axial section and folded section in FIG.

  Figure 6 shows in section a constructional variant of the central bar 7 and the sleeve 16 having a torsion limiting assembly. A torsion limitation of the plasticizing zone 13 will be obtained by producing the trimming sleeve 16 in two parts nested together by a jaw assembly 19, shown in perspective in FIG. 7, having a rotation clearance corresponding to the deformation limits of FIG. desired plastification, for example of 50 in front damping and 20 in rear damping. The jaw assembly may be of the open type, as in FIG. 7, the claws 19 engaging in the thickness of the sleeve, or of the closed type, as shown in perspective section in FIG. 8, the fitting being effected radially. in cavities of an extra thickness in which fit together with rotating play the two assembly ends of the sleeve.

  From these examples, it is possible to consider all programmed damping solutions to achieve the desired result and thus limit the maximum effort exerted on passengers in different phases of deceleration front and rear.

  The angular play of the file, particularly with respect to the bar 7 must be limited. Indeed, given the relatively small section of the latter compared to the distance between the axis of the headrest of the backrest, the slightest play can lead to a significant displacement of the top of the file and thus inaccuracy trimming angular backrest as well as vibrations and noise. It is expected to overcome the building blocks at the adjusting nut 5, which transmit all the effort directly to the central bar 7 and therefore to its energy absorbing device.

  For this purpose, according to the invention, as indicated in FIGS. 9, 10 and 11, a coupling of two nuts 20, 21, free to slide relative to one another and angularly immobilized by the central bar 7 energy absorption. The control screw 11 for adjusting the inclination of the backrest drives a nut 23 free axially but immobilized angularly by the nuts which abuts in the nut concerned in the direction of rotation of the control screw. At rest, the nuts 20-21 are opposed by spacing or approximation under the action of a spring 24 which ensures their permanent locking between the tube 1 and the central bar 7, thus eliminating all positioning and assembly games the backrest on the seat. The thrust on one or other of the nuts 20,21 of the nut 23 actuated by the adjusting screw 11 eliminates this blockage and causes each to cause the tube 1, the drive nut pulling or pushing the other and thus position it angularly with respect to the central bar 7. The helical ramps 2 of the tube 1 on which the nuts 21-22 come to bear in an opposite manner force them, pushed by the spring 24, to counteract on the grooves 8 of the central bar 7, which blocks the axial displacement of the two nuts and causes the jamming of the entire mechanism and consequently the neutralization of the tilting of the backrest by jamming at rest obtained by mating the two nuts. The clearance necessary for the operation of the reclining mechanism of the backrest will be obtained automatically when the two nuts 2021 are unhooked by the control of the adjusting screw 11 of the backrest position and the corresponding thrust of the nut 23 on one nuts for unlocking.

  In the case of jamming obtained by bringing the two nuts 20-21 together, as indicated in FIG. 10, they are in operation in the maximum spacing position as if it were a single nut with ribs 12 continuous, the central part of which would have been removed. The space 22 separating the two nuts should be sufficient to allow jamming, without them in contact at rest, under the action of the pressure of a spring 24 bringing the two nuts together. In order to avoid a gap lock, a retaining screw 25 will limit the maximum spacing of the two nuts so that their helical ribs 12 are in line with one another as if they formed a single unbroken rib. The unlocking by spacing of the two nuts will be done automatically during any trimming of the backrest position, driving a drive nut under the thrust of the nut 23, then towing the other nut and automatically unlocking the wedge by the spacing of the two nuts 20-21.

  In the case indicated in FIG. 1 of a wedging obtained by spacing the two nuts under the action of nuts 23 located on the opposite faces of the nuts against a spacer spring 24 located between the nuts, the operating principle will be identical, but inversely. The control of the "driving" nut thrust by the action of a nut 23 associated with it will cause a connection unlocking the mechanism, the drive nut driving the other nut thrust. This solution is a little more complex than the previous one by requiring two nuts 23 and their spacing adjustment, on the other hand, screws for retaining the spacing of the nuts are not necessary, this distance being limited by the jamming and unblocking being ensured by the bringing together of the nuts one of the other, this approximation being limited by the setting in support of the two nuts one on the other.

  By these devices are thus neutralized the games both on the side of the central bar and helical ramps, allowing to no longer be dependent on the dimensions of construction and their tolerances. Furthermore, the combination of two walnuts narrower than a single walnut promotes their realization sintered material, especially steel, high density, and increases the contact surface on the side of each of the helical ramps of about 50%.

  Figure 12 shows in axial section the bearing 10 fixed on the seat of the seat 27 and receiving the rotating end of the torsion bar 7 opposite the welded bearing. The torsion of the bar 7 following a variation of uncontrolled inclination of the seat back in an accident, will automatically trigger an articulated seat of the seat, called "anti-submarining", raising the seat by mechanical means such as a spring hinge and thereby preventing slipping of the occupant along the seat forward, and / or belt pre-tensioning mechanism, tilting forward of the seat; headrest or the upper part of the backrest in the event of a rear impact or any other auxiliary functions of protection against front or rear impact by means of an insert 25 fixed on the end of the torsion bar 7, limited in rotation in the bearing by the angular displacement of the bar about 5 in front and back, by a fitting with clearance 28, this part being provided with a trigger arm 26 rotated and ensuring the triggering of the auxiliary devices protec its function is to activate. Figure 13 shows in perspective the assembly head of the part 25 on the bar 7, the trigger arm 26 is not shown.

  FIG. 13-1 represents, in simplified axial section, an alternative embodiment of the end of the mechanism represented in FIG. 3 corresponding to its zone of plasticization, making it possible to avoid any risk of accidental jamming. Indeed, in extreme cases, if the central bar 7 is not on the same axis as the tube 1 and the trimming nut 5, the torsion forces can cause a relative angular displacement generating a radial displacement between the nut trimming and fixing the central bar in the bearing, causing jamming of the mechanism due to eccentricity and thus a blockage in position of the siege seat back impede the release of an occupant. This risk will be avoided by arranging the tube 1 and the central bar 7 on a common axis 29, with corresponding increase in the diameter of the extremities of the tube 1, as indicated in the section of FIG. 13-2, thus eliminating any risk of jamming by rotation around the same axis of the nut 5 or 20-21.

  In order not to increase the diameter of the mechanism in the central part of the tube 1 and not to disturb the rear passengers, only the two extremities of the tube 1 may be increased in diameter at the level of the fastening on the seat posts 3, 4 so that their axis of articulation is concentric with that of the central bar 7, avoiding the eccentricization of the areas of plasticization. This arrangement can be achieved either by a frustoconical flare 30 offset during shaping of the tube, or by the addition on the tube eccentric rings reported.

  It is the same for the control screw 11 which is immobilized axially and radially in the bearing, as represented in FIG. 13-1, and which can undergo angular displacement during the plasticization in torsion of the central bar 7, which will have the effect of causing it to jam and prevent its operation in an accidental situation. This risk of jamming will be avoided by producing the screw 11 in two parts, one of which, the screwing zone 11-1, will remain parallel to the axis of the central bar 7, in order to be able to freely turn in the nut 5, 20-21 and will be connected by a cardan type hinge means 11-3 to a control portion 11-2 corresponding to the plasticizing zone of the central bar, this control portion 11-2 being hingedly mounted in the bearing 9, for example by hemispherical bearing faces 31 of its axial stops.

  The ends of the tube 1 comprise eccentric rings arranged to allow a refocusing of the central bar 7 corresponding to the axis of the bearings and the corrugated orifice allowing the passage of the bar 7 in the nut 5, 20, 21 to eliminate all jamming of assembly or deformation resulting from accidental operation.

  FIG. 15 shows in section XV-XV a bearing 10 for assembling the mechanism to the side of the seat cushion according to the front view of FIG. 14. Made of stamped sheet metal, these bearings 10 comprise fixing flanges 32 on the flanks of the seat of the seat on which they are fixed by two screws 33 usually placed in the upper part of the seat, not shown. This arrangement will be reinforced by an additional fastening 34 at the bottom end of a prolongation extension of maximum downward 35 of the fixing flange of the bearing. Considering the very significant efforts following the arrow 36 exerted on the bearings in the case of safety belts retained by the backrest, this provision will reduce the forces exerted by the bearings on the flanks of the seat base. The fastener 34 located in the lower part may advantageously correspond to the axis of the existing anchoring screw of the seat belt, with a correlative simplification of the assembly and a corresponding reduction in cost. The extension 35 of the flange 32 of the bearing will then be wedged between the surface of the seat and the attachment plate of the belt, thus forming a rigid and resistant stack.

  The bearings 10 thus simultaneously provide the fastening functions on the seat back equipped with its reclining tilt mechanism continuously, preferably removably, articulation of the backrest on the seat, fixing the bar 7 d energy absorption connected to the seat, one of its ends being fixed, preferably welded to the corresponding bearing 9, the second bearing 10 allowing to leave in a predetermined manner an angular play on the other end of the bar, of maintain the spacing and verticality of the sidewalls of the seat, to integrate a concentric quick-shift discontinuous tilt adjustment mechanism to the continuous tilt trimming mechanism.

  FIG. 15-1 schematically shows a seat back frame with a single telescopic central column 37 integral with the middle of the spacer tube 1, at the level of the trimming nut, with an axial folded section showing the rack 38 for adjusting the height of the column and top view showing the location of a back shell 39.

  The seat belt exit 40 and the headrest 41 are integral and adjustable simultaneously in height and represented in maximum lift. The control of the movable part can also be made by a geared motor incorporated in the headrest actuating a screw meshing in a nut integral with the fixed column 37. This backrest structure allows a saving of space at the rear of the part and else of the column 37 as well as any freedom of design of the upholstery of the file from the shell 39, which can be personalized. This light alloy frame with a 39 magnesium shell allows a significant weight gain compared to seats of the state of the art.

  FIG. 15-2 shows an assembly bearing 10 according to FIGS. 14 and 15 mounted on a seat flank 27 (FIG. 12) of seat with separate high-strength sheet metal extensions, with stiffening ribs 42 and fallen edges. 43 in opposition facilitating their attachment to the flanks 44 of a seat box of the seat, made at the slightest weight of light alloy and which will integrate the movable seat of a device called "anti-submarining". The access light 45 receives the control end of the triggering arm 26 (FIG. 12) which, by pulling on a control cable, will actuate an unlocking pin freeing the lifting springs from the mobile seat of the device called "d". anti-submarining ". The triggering arm 26 may simultaneously actuate a control cable for triggering a spring cylinder actuating a pre-tensioning device of the safety belt by releasing a release pin of the spring actuating the pre-tensioner and can be equipped with a non-return device avoiding the stress relief of the belt. This relatively simple structure, low weight, purely mechanical and does not require electrical connection will advantageously replace the pyrotechnic devices assuming the same functions.

  FIG. 16 shows a discontinuous backrest orientation mechanism by ratchet 46 and positioning cam 47 mounted on a rotary bearing 48 in the tilted forward position of the stored return backrest. The bearings make it possible to integrate rapid positioning mechanisms. tilting of the backrest by discontinuous position adjustment by means of retractable latching pawls 46 of a rotating part of the bearing 48 by locking positioning notches 49. These notches position the rapid positioning angles of the backrest, for example - 25 relative to the vertical for the standard position, - 75 for the sleeping position, + 30 for an advanced position. In the latter case, simply unlock the pawl 46 and release the control handle and push the folder until abutting. To return to position -25, it is not useful to operate the handle.

  This multi-function quick-shift mechanism thus allows an advanced position adjustment of the backrest, for example by a forward inclination of +30, with return stored in the standard position without action on the control lever, a setting setting in tablet ensuring the locking of the backrest on the seat by a notch with successive bearings ensuring the automatic retention of the backrest in the tightest position, taking into account the real position due to the variable position of the continuous adjustment, the setting back position berth at -75 for example, with obligation to engage the retaining pawl ensuring the positive security of immobilization of the file. The continuous trimming mechanism makes it possible, if necessary, to go beyond this limit and operates in all the positions of the discontinuous adjustment making it possible to obtain, associated with the continuous trimming, any position between the setting in tablet and the sleeping position. beyond -75.

  FIG. 17 shows a simplified axial section of the same device showing the assembly of the rotary bearing 48 on the fixed bearing 10, with a ring 50 for retaining the bearing 48 and the axis 51 of rotation of the pawl 46. On the same axis 51 is fixed, opposite the pawl 46, a rudder 52 supporting a lock securing the uncontrolled opening of the pawl in all discontinuous positions.

  FIG. 18 shows the same pawl-side device according to FIG. 16 in the normal rectification position of the backrest, at -25 of inclination, with the trace 53 of the engagement movement of the pawl 46. The pawl 46 is equipped with a tail 46-1 having two functions: - Limiting the maximum opening angle 53 of the pawl 46 shown in FIG. 18; - To bear on the cam 46-2 in order to force the pawl to go down into the notch of the sleeping position - 75 without being able to go beyond it in order to secure this position and to avoid, for example, setting the horizontal of an unlocked folder.

  However, it is possible to exceed the angle of - 75 once the ratchet is locked by acting on the continuous adjustment.

  Figures 19 and 20 show the opposite side of the discontinuous backrest orientation device according to Figures 16, 17, 18, mounted on the opposite face of the bearing 10, with its cable control system of a latch 54 and a spreader 55 mounted oscillating on an axis 56 simultaneously driving the pawl 46, shown in phantom, by the spreader 55. The bearings 9,10 each comprise a rapid positioning mechanism of recline of the backrest by discontinuous position adjustment by means of a retractable locking pawl 46 of a rotatable part of the bearing 48 by blocking positioning notches 49 corresponding to the rapid positioning angles of the backrest, with the assembly of the rotary bearing 48 on the fixed bearing 10 by a retaining ring 50 of the bearing 48 and its immobilization in rotation on the axis 51 of rotation of the pawl 46 being mounted, opposite the pawl 46, a spreader 55 supporting at one of its ends a latch 54, with its system cable control, the spreader 55 being mounted oscillating on the axis 51 of simultaneous driving of the pawl 46 by the spreader 55, a spring 57 attached to the end of the spreader 55 opposite the latch 54 reminding the lifter, and by therefore the pawl 46 in the automatic closing position, the second spring 59 ensuring the return of the latch 54 against a limit stop 58 in automatic closure of the latch 54, under the action of a control cable coming out of the stop 62 of the cable sheath and fixed to the latch 54 by the fastening lug 63, the latch 54 will pivot at an angle 64 releasing its support finger 65 from the stop 60 allowing the tilting of the spreader 55 and thus the release of the ratchet 46 of its positioning notch 49 allowing rotation of the bearing 48.

  The release of the pawl 46 of the notch in which it is engaged is automatically and continuously in a single traction maneuver on the cable. With the cable sheath resting on the lug 62, the end of the cable drives the traction lug 63 varying the angular position of the latch 54 by the value of the angle 64 until the finger is brought into contact with one another. support 65 on the stop 61, thus releasing the bearing 60 whose purpose is to immobilize in the closed position the pawl interposed rudder.

  The lower spring 59 has allowed the latch to be released, the lifter 55 remaining in the closed position of the pawl 46 by the action of the stronger spring 57, the whole as shown in FIG.

  The pulling of the cable becoming stronger than that of the spring 57, the spreader 55 tilts and drives the pawl 46 via the axis 56, making them integral as shown in Figure 19. The pawl having been disengaged, for example from the standard position of -25 shown in Figure 18, just slightly tilt the backrest to press on the tab separating two notches and release the handle, the pawl 46 will automatically re-engage in the desired notch under the action of the return spring 57, the spring 59 then putting the latch 54 in its closed position, the thrust finger 65 automatically coming into locking position under the stop 60.

  The rotary bearing 48 is provided with a cam 46-2 arranged in the same plane as its notches 49 and the pawl 46, intended to act on the tail 46-1 of the pawl 46 which limits the maximum opening of the ratchet 46, the cam 46-2 raising the tail 46-1 having the effect of forcing the pawl 46, for the sleeper position - 75, to position necessarily in this slot without being able to go beyond.

  The combination of the two mechanisms, with continuous and discontinuous adjustment, as previously described makes it possible to avoid possible malfunctions due to a defect in the synchronization, usually necessary, of several associated mechanisms.

  In the design of the continuous trimming mechanism, there is provided a fixed bearing welded to one end of the bar 7, the other bearing having a few degrees of angular freedom with respect thereto. This degree of freedom, necessary for other functions previously described, allows the mobile part supporting the notches of the non-welded bearing on the bar 7 not to be flanged in rotation by the latter and to be angularly aligned in a perfect manner with its ratchet, thus avoiding any problem of synchronization.

  FIG. 21 shows in perspective the whole of the discontinuous trimming mechanism according to the invention, the bearings of which are equipped with discontinuous orientation devices according to FIGS. 16 to 20 with unlocked pawl and rudder, in a position of change of orientation. fast of the seat back.

  FIG. 22 shows in perspective, on a larger scale, the preceding mechanism in the locked position of the pawl and the rudder, with a section of the spacer tube showing the disposition of the central bar, the control screw and its internal guide grooves. of the nut.

  The safety device for motor vehicle seat according to the invention meets all the safety requirements imposed for such seats, while providing all the possibilities of trimming, continuous and discontinuous, seat position, including the inclination of backrest, by a compact, low weight, and fully mechanical ensuring its reliability and durability trimming.

Claims (3)

claims   1- Trimming nut for continuous angular orientation device of a twisting energy absorption bar device characterized in that it is formed of a coupling of two nuts (20,21), free in sliding relative to each other and angularly immobilized by a central bar (7), their axial displacement in opposition by spacing or approximation under the thrust of a spring (24), each driving the tube (1) in a opposite direction and thus immobilizing it angularly by locking on the splines (8) of the central bar (7), the helical grooves (2) of the tube (1) in which the helical ribs (12) of the nuts (20,21) are supported in opposite manner requiring them to be against the support bar (7), blocking the axial displacement of the two nuts (20, 21) and causing the jamming of the entire mechanism and consequently the neutralization of the device failover game, the game requires to the operation of the mechanism being obtained automatically when the two nuts (20-21) are unhooked by the control of the angular position adjusting screw (11) and the corresponding thrust of the nut (23) on one of the nuts ensuring the unlocking.   2- Trimming nut according to claim 1, characterized in that, in the case of jamming obtained by bringing the two nuts (20, 21) closer together, they are in operation in the maximum position of separation as if was a single nut with ribs (12) continuous and which would have removed the central part, the space (22) separating the two nuts to be sufficient to allow jamming, without them in contact at rest under the action of the pressure of a spring (24) bringing the two nuts together, a retaining screw (25) limiting the maximum spacing of the two nuts, the release by spacing the two nuts will be carried out automatically, under the thrust of the nut (23) of a "drive" nut, then towing the other nut and automatically unlocking the wedge by the spacing of the two nuts (20-21).   3- trimming nut according to claim 1, characterized in that, in the case of jamming obtained by spacing the two nuts under the action of the pressure of a spring (24) separating the two nuts one of the other, the control of the adjusting screw (11) and the corresponding thrust of one of the nuts (23) on one of the nuts (20,21) will bring them together unlocking the compression mechanism of the spacer spring (24). ) located between the nuts (20, 21), the "drive" nut pushed by the nut (23) pushing the other nut ..