Patent Publication Number: US-2023158924-A1

Title: Seat rail pair for longitudinal adjustment of a vehicle seat and energy absorber and locking device, in particular for such a seat rail pair

Description:
The present application claims priority of German patent application no. 10 2020 108 799.3 “Seat rail pair for longitudinal adjustment of a vehicle seat as well as energy absorber and locking device, in particular for such a seat rail pair”, filed on Mar. 30, 2020, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates generally to adjusting the position of a vehicle seat in an adjustment direction, and more particularly relates to provisions for dissipating energy in or on a vehicle seat in the event of a crash. Further aspects of the present invention relate to an energy absorber for converting crash energy in a vehicle by deformation of a deformation member, and to a locking device for releasably locking a first component which is slidably guided in an adjustment direction relative to a second component in a vehicle interior of a motor vehicle. 
     PRIOR ART 
     A seat rail pair for adjustment of a motor vehicle seat in an adjustment direction, which usually coincides with the longitudinal direction of the vehicle, and for locking a desired position of the motor vehicle seat in the adjustment direction as claimed in the preamble of claim  1  is disclosed in DE 196 13 506 A1. The lower rail is embraced over part of its length from below by a carriage bent from a sheet metal, which forms an outwardly projecting detent strip on its one lateral leg and is firmly connected to the lower rail by a rivet. A detent plate rests on the upper side of the upper rail and is firmly connected to the upper rail and provided with detent holes in an area overlapping the detent strip, which are aligned with the detent holes of the detent strip of the carriage in the selectable longitudinal adjustment positions of the seat. When the seat is locked, detent pins engage through the aligned detent holes. In the area of its underside, the carriage is provided with a row of apertures running in the longitudinal direction of the lower rail, which are separated from each other by transverse webs. A wedge body fixed to the underside of the lower rail engages in the foremost of the apertures, the wedge section of which is directed against the transverse webs. The transverse webs each act as energy-absorbing elements in the event of a crash, dissipating crash energy by deformation. 
     Although the structure of the seat rail pair is relatively compact, in the case of electric longitudinal adjustment of the vehicle seat, a large number of additional components are arranged in a path that introduces the force acting on the vehicle seat into the vehicle structure, which further influence the dissipation of crash energy, so that it is difficult to specifically influence the dissipation of crash energy. 
     WO 2013/046200 A1 discloses the installation of an energy absorber element designed as a tubular hollow profile directly between the two rails of a seat rail pair for adjustment of a motor vehicle seat. The coupling of an electric drive for adjusting the upper rail relative to the lower rail is not provided. 
     Energy absorbers are known from the prior art, in which rod-shaped or tubular components are selectively deformed, for example by folding, buckling, bending, tearing and the like, in order to reduce or convert crash energy in a vehicle. These energy absorbers are very complex to manufacture and design. The definition of nominal fracture/target deformation portions must be designed via elaborate tests. The force/energy levels are very strongly dependent on the geometry, material tolerances, friction, crash or speed of deformation, etc. This results in very large tolerances in the conversion of the crash energy. As a result, the amounts of residual crash energy, acceleration and external forces acting on the vehicle occupants vary greatly, making the design of safety systems even more difficult. Highly fluctuating energy conversion characteristics may additionally cause force pulses to act on the body or the vehicle occupant, which can have a detrimental effect. Furthermore, the known crash elements can usually only be designed for one energy conversion level/force level. These energy absorbers are installed primarily in the vehicle body. Examples of such energy absorbers are disclosed in DE 10 2007 051 815 B4, DE 198 58 432 A1, DE 20 2007 012 746 U1 or DE 10 2014 211 510 A1. 
     EP 1 197 429 A2 discloses an energy absorber for absorbing energy from a vehicle in an impact situation. The energy absorber comprises a first part, a second part, and an elongated deformable member attached to the first part and extending through a deformation structure carried by the second part. The elongated deformable member normally acts as a connecting member or strut between the first part and the second part. When the force acting between the first part and the second part in a predetermined direction exceeds a predetermined amount, the elongated deformable member is progressively forced through the deformation structure as the distance between the first part and the second part changes, thereby forcing the deformable member to undergo plastic deformation. The deformation structure is configured to cause plastic deformation with substantially no change in the cross-sectional area of material of the deformable member, to provide a relatively gradual retardation. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a seat rail pair for adjustment of a vehicle seat in an adjustment direction, for which a reduction in crash energy can be selectively specified in a simple and reproducible manner by means of a simple and inexpensive structure. According to a further aspect of the present invention, there is to be provided an energy absorber for converting crash energy in a vehicle by deformation of a deformation member, which enables a very well controllable and reproducible conversion of crash energy. According to a further aspect of the present invention, there is to be provided a locking device for releasably locking a first component which is guided so that it can be displaced in an adjustment direction relative to a second component in a vehicle interior of a motor vehicle, in particular for releasably locking a component of a vehicle seat once, which locking device can be manufactured in a simple and inexpensive manner and can be reliably and very quickly unlocked. According to a further aspect of the present invention, there is to be provided a vehicle seat which is fastened to a fastening rail of such a seat rail pair. 
     According to the present invention, these problems are solved by a seat rail pair with the features as claimed in claim  1 , by an energy absorber with the features as claimed in claim  16 , by a locking device with the features as claimed in claim  26 , and by a vehicle seat with the features as claimed in claim  35 . Further advantageous embodiments are the subject-matter of the dependent claims. 
     As claimed in a first aspect of the present invention, there is provided a seat rail pair for adjustment of a vehicle seat, in particular a motor vehicle seat, in an adjustment direction, comprising a guide rail extending parallel to the adjustment direction for fastening to a vehicle floor, and a fastening rail adjustably guided on the guide rail in the adjustment direction for fastening the vehicle seat, wherein an energy absorber element, in particular an energy absorber as disclosed in more detail below, is provided in a path which introduces the force acting on the vehicle seat into the vehicle structure, which element permits a movement of the vehicle seat in the adjustment direction under plastic deformation when a predetermined value of the force is exceeded. 
     According to the present invention, an adjustment element for adjusting the vehicle seat in the adjustment direction is guided on the guide rail or on the fastening rail and is coupled to the guide rail, wherein the fastening rail can be adjusted relative to the adjustment element in the adjustment direction with deformation of the energy absorber element, when the predetermined value of the force acting on the vehicle seat is exceeded. 
     The coupling of the fastening rail to the adjustment element is not released during driving or during normal adjustment of the vehicle seat, for example for a comfort setting, and remains fixed. In the event of a crash, on the other hand, the coupling between the fastening rail and the adjustment element is released and the fastening rail can move in the guide rail relative to the adjustment element. An energy absorber is integrated between the fastening rail and the adjustment element. During driving or during normal adjustment of the vehicle seat, the energy absorber is firmly coupled to the fastening rail and the adjustment element. In the event of a crash, the energy absorber is still firmly coupled to the fastening rail and the adjustment element. The energy absorber converts the crash energy. The adjustment element, which is coupled to the guide rail, remains coupled to the guide rail in the event of a crash and transfers the crash energy to the seat frame or vehicle structure. The fastening rail guides the entire seat in a defined direction in the event of a crash. 
     The adjustment element may be a rail profile designed in the manner of a conventional upper rail, which is preferably relatively short and guided in the guide rail. The guide rail itself is preferably designed in the manner of a conventional lower rail and serves to fasten the respective seat rail to the floor of a vehicle body. The actual vehicle seat is fastened to the second upper rail. The second upper rail is expediently designed as a relatively long rail section which is also guided in the guide rail. The two upper rail segments represent separate components which are suitably coupled to one another. 
     According to a further embodiment, the energy absorber element is coupled via a breakaway member in the path that introduces the force acting on the vehicle seat into the vehicle structure, the breakaway member being destroyed when the predetermined value of the force is exceeded. This allows the rigid coupling between the fastening rail and the adjustment element to be released, allowing relative movement between the fastening rail and the adjustment element while the energy absorber is deformed. 
     According to a further embodiment, the energy absorber element and the breakaway member are interchangeably mounted in or on the seat rail pair so that the vehicle seat can be returned to its original condition prior to a crash event after the installation of new replacement parts and can continue to be used. 
     According to a further embodiment, the energy absorber element is coupled via a locking device having a predetermined triggering threshold in the path that introduces the force acting on the vehicle seat into the vehicle structure. When the triggering threshold is exceeded, i.e., when the predetermined value of the force acting on the vehicle seat is exceeded, the locking device is unlocked or released, thereby releasing an adjustment of the fastening rail relative to the adjustment element with deformation of the energy absorber element in the adjustment direction to dissipate crash energy. The locking device may thereby be unlocked purely mechanically or by activating an electric actuator. 
     According to a further embodiment, an electronic processing unit may be provided that is configured to generate an activation signal for activating an electric actuator and unlocking the locking device on the basis of a pre-crash input signal. 
     An even more flexible activation of the electric actuator can be achieved by providing electronic sensors for sensing at least one adjustment parameter of the vehicle seat and/or at least one parameter concerning the vehicle seat and for outputting corresponding signals, and by providing an electronic processing unit for processing the signals outputted by the electronic sensors, which is configured, to generate, on the basis of the signals output by the electronic sensors, the activation signal for triggering the actuator and for unlocking the locking device when the predetermined value of the force acting on the vehicle seat is exceeded and when the at least one setting parameter of the vehicle seat and/or the at least one parameter relating to the vehicle seat is respectively within a predetermined range. The triggering of an unlocking of the locking device can thus be made dependent, for example, on the current position of the vehicle seat in the adjustment direction, on the weight of a vehicle occupant, on an inclination of a seat backrest, on a rotational position of a seat part of the vehicle seat or of the vehicle seat itself, etc. 
     According to a further aspect of the present invention, which may also be claimed independently of the above-described seat rail pair, there is provided an energy absorber for converting crash energy in a vehicle by deformation of a deformation member, comprising a deforming member presetting the deformation and comprising a deformation member, which is designed as a tubular hollow profile extending in a longitudinal direction and is guided so that it can be displaced relative to the deforming member in the longitudinal direction, an opening having a predetermined inner profile being formed in the deformation member, the deformation member extending through the opening, wherein a displacement of the deformation member relative to the deforming member in the longitudinal direction in the event of a crash causes a deformation of the outer profile of the deformation member by the inner profile of the opening. 
     In the event of a crash, a section of the hollow profile that has not yet been deformed is forced through the opening of the deforming member. The inner profile of the deforming member causes the section of the hollow profile that has not yet been deformed to be deformed. 
     Preferably, the deformation takes place exclusively or almost exclusively as bending of wall sections of the not yet deformed section of the hollow profile. Thus, the conversion of energy may be implemented primarily by deformation (of)/bending the hollow section, thus minimizing friction. This makes the conversion of energy very controllable and reproducible because frictional effects, which otherwise worsen the reproducibility of dissipation of crash energy, are avoided according to the present invention. By varying the initial tube geometry (width, height, diameter, . . . ) and the material used, the characteristics of energy conversion can be controlled very precisely and reproducibly. 
     According to a further embodiment, the inner profile of the opening and the profile of the tubular hollow profile are designed such that the neutral fiber of the tubular hollow profile is identical before and after the deformation of the deformation member. For this purpose, the inner profile of the opening may vary in the longitudinal direction, in particular in accordance with a continuous function, wherein a circumferential length of the inner profile of the opening is constant for each position in the longitudinal direction. Thus, a very reproducible deformation of the tubular hollow profile can be achieved. 
     According to a further embodiment, the deformation member has, at least in sections, an outer profile with an n-fold rotational symmetry, where n is an integer and n is greater than or equal to three, so that torsion of the energy absorber can be effectively prevented. 
     According to a further embodiment, the deformation member has a plurality of pre-embossments in the radial direction, each of which is formed with mirror symmetry with respect to an axis to the geometric center of the tubular hollow profile. 
     According to a further aspect of the present invention, which can also be claimed independently of the seat rail pair described above and/or the energy absorber described above, there is provided a locking device for releasably locking a first component, which is guided so that it can be displaced in an adjustment direction relative to a second component in a vehicle interior of a motor vehicle, in particular for the one-time releasable locking of a component of a vehicle seat, comprising a pivotally mounted locking arm having a plurality of locking bodies which are arranged at a distance from one another in the adjustment direction and, in a locked basic position of the locking arm, each engage via associated openings which are formed in the first and second components, respectively, wherein the locking arm is pressed down into the locked basic position as long as a predetermined value of a force acting on the first component is not exceeded, and wherein the locking arm is released or de-locked when the predetermined value of the force acting on the first component is exceeded, so that the locking arm is pivoted into a release position in which the engagement of the locking bodies in the associated openings is released. 
    
    
     
       OVERVIEW ON DRAWINGS 
       Hereinafter, the invention will be described in an exemplary manner with reference to preferred embodiments and with reference to the accompanying drawings, which show: 
         FIG.  1    the general configuration of a longitudinal adjustment device for longitudinal adjustment of a vehicle seat according to the present invention in a schematic view; 
         FIGS.  2   a - 2   c    a longitudinal adjustment device for vehicle seats according to the present invention in different longitudinal positions and in schematic views; 
         FIGS.  3   a - 3   f    each in a longitudinal section and in a partial perspective section, a longitudinal adjustment device for vehicle seats according to the present invention in different longitudinal positions; 
         FIG.  4    in a schematic representation, the basic structure of an energy absorber for a longitudinal adjustment device for vehicle seats according to the present invention; 
         FIGS.  5   a - 5   e    in various views, an energy absorber according to the present invention in an initial position prior to deformation of its deformation sections; 
         FIGS.  6   a - 6   e    in corresponding views, the energy absorber according to  FIGS.  5   a - 5   e    during or after a deformation of its deformation sections; 
         FIG.  7   a    in a schematic side view, an energy absorber according to a further embodiment of the present invention; 
         FIG.  7   b    an exemplary characteristic curve of the energy absorber according to  FIG.  7     a;    
         FIG.  8    in schematic sectional views, further embodiments of an energy absorber according to the present invention; 
         FIGS.  9   a  and  9   b    a locking mechanism for a longitudinal adjustment device for vehicle seats according to the present invention in a locked and an unlocked position; 
         FIG.  10    in a schematic perspective view, a longitudinal adjustment device for vehicle seats according to the present invention with a locking mechanism according to  FIGS.  9   a    and  9   b;    
         FIGS.  11   a - 11   c    a further exemplary embodiment of a locking mechanism for a longitudinal adjustment device for vehicle seats according to the present invention in a locked position and in an unlocked position and in a perspective view; 
         FIGS.  12   a - 12   c    in various views, a longitudinal adjustment device for vehicle seats according to the present invention, comprising a locking mechanism according to  FIGS.  11   a - 11   c   ; and 
         FIG.  13    in a schematic block diagram a circuit diagram, a control device for a further embodiment of a longitudinal adjustment device for vehicle seats according to the present invention. 
     
    
    
     In the drawings, identical reference numerals designate identical or technically equivalent elements or groups of elements. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to  FIG.  1   , the basic principle of a longitudinal adjustment device for a vehicle seat according to the present invention will first be explained. The longitudinal adjustment device  1  shown in  FIG.  1    is formed by a lower rail generally designated by reference numeral  10  and an upper rail guided therein for longitudinal displacement in the x-direction (adjustment direction) and generally designated by reference numeral  21 . The lower rail  10  is intended to be mounted on the floor of a vehicle body, while the vehicle seat  8  is attached to the upper rail  21  via mounting brackets  81 . Lower and upper rails  10 ,  21  are each formed as profiles with a substantially U-shaped cross-section and are produced by punching and stamping from a flat sheet material of suitable strength. The two U-shaped profiles alternately engage with each other in the assembled state, thereby forming a total of two tear-resistant embracing areas which provide a high degree of mechanical stability for the longitudinal adjustment device  1 . The two rails  10 ,  21  are guided in the adjustment direction x by guide means and kept at a distance from each other to reduce friction. The guide means may be designed as rolling members, for example as rollers, in order to achieve the lowest possible friction, but may also be designed exclusively as sliding members, for example made of a plastic material. Although specific embodiments of such rail profiles are shown in the further figures of this application, the present invention expressly shall not be deemed to be delimited to the use of these particular rail profiles, but rather may be applied to any other suitable rail profiles. 
     According to  FIG.  1   , the upper rail comprises a total of two segments, namely a second upper rail  21  to which the vehicle seat  8  is attached, and a first upper rail  20  which serves for the actual adjustment of the vehicle seat  8  in the adjustment direction x along the lower rail  10 . In this sense, the first upper rail  20  may also be considered as an adjustment member for adjusting the vehicle seat  8  in the adjustment direction x, which is guided on and coupled to the lower rail  10  acting as a guide rail. Alternatively, the first upper rail  20  or the adjustment member  20  may also be guided directly in the second upper rail  21 . In this case, the longitudinal adjustment can be designed for a manual or electrically driven longitudinal adjustment. In the case of a manual longitudinal adjustment of the vehicle seat  8 , the first upper rail  20  may be a rail profile which is guided on or in the lower rail  10  in the manner of the second upper rail  21  and is provided with a mechanical locking device for locking a position of the vehicle seat  8  in the adjustment direction x as selected by the user, for example by means of a locking device comprising a plurality of locking pins, as disclosed in WO 2006092118 A2 of the Applicant. In the case of an electrical longitudinal adjustment of the vehicle seat  8 , the adjustment element may be an adjusting device designed as a spindle drive, as disclosed by way of example in DE 102007027410 A1 of the Applicant, comprising a spindle extending along a spindle axis, which is arranged in a free space between the lower rail  10  and the first upper rail  20  and is fastened to the lower rail  10 , and with a spindle nut arranged rotatably on the spindle, which is mounted in a housing and, in order to generate an adjusting force, is set in rotary motion by an electric drive motor in order to move along the spindle and transmit an adjusting force to the adjustment element  20  via a housing, as disclosed by way of example in German utility model DE 20 2006 004 613 U1 of the Applicant, the entire contents of which are hereby expressly incorporated by way of reference. 
     Expediently, the first upper rail  20  is accommodated and guided in a guide channel formed by the profile of the lower rail  10  or, in order to achieve the longest possible adjustment path, the first upper rail  20  is formed as a relatively short rail segment with a U-shaped profile which engages in the profile of the lower rail  10  in the manner of the second upper rail  21  in order to form two tear-resistant embracing areas. 
     Expediently, the adjustment element  20  thus formed is rigidly coupled to the lower rail  10  via the mechanical locking device or via the electrical longitudinal adjustment device. 
     In a normal operating condition, when no high accelerations or forces due to a crash are acting, the second upper rail  21  is rigidly coupled to the first upper rail  20  via a coupling device  5  which includes an energy absorber, as described in more detail below. The second upper rail  21  with the vehicle seat  8  attached thereto thus directly follows an adjustment of the first upper rail  20  or of the adjustment element  20  in the adjustment direction x. The longitudinal adjustment of the upper rail formed as a whole by the two components  20 ,  21  is thereby limited by end stops or the like. 
     As shown schematically in  FIG.  1   , the coupling device  5  is provided in a path via which a force acting on the vehicle seat  8  is introduced into the vehicle structure. A suitable design of the coupling device  5  ensures that the energy absorber incorporated in this path is bridged in a normal operating state, so that a rigid coupling between the two components  20 ,  21  is ensured in a normal operating state. For this purpose, suitably designed coupling sections  50  may be provided, via which an energy absorber is bridged in a normal operating state but which is incorporated into the path via which the force acting on the vehicle seat  8  is introduced into the vehicle structure, when a predetermined value of the force acting on the vehicle seat  8  is exceeded (i.e. in the event of a crash), so that the energy absorber then permits, under plastic deformation, a movement of the second upper rail together with the vehicle seat  8  fastened thereto in the adjustment direction x relative to the adjustment element or the first upper rail  20 . During this relative movement between the second upper rail  21  and the adjustment element or the first upper rail  20 , the energy absorber dissipates crash energy by material deformation. The relative movement is limited by end stops or the like to a range over which the energy absorber is capable of dissipating crash energy by material deformation. 
     In this way, a rigid coupling of the vehicle seat  8  with the adjustment element  20  can be achieved in a normal operating state, but in the event of a crash, when the force acting on the vehicle seat  8  exceeds a predetermined threshold value, an energy absorber can be switched in to dissipate crash energy by material deformation through a relative movement between the second upper rail  21  and the adjustment element or, respectively, the first upper rail  20  over a range over which the energy absorber is capable of dissipating crash energy by material deformation, and to thereby reduce the forces acting on the vehicle seat  8  or a vehicle occupant in the event of a crash. It may expedient for this purpose to provide the option to switch rapidly between the normal operating state and the crash state, for example by means of a rapid adjustment of the operating state of the connecting sections  50  or by means of a suitable design of a coupling device, as described in more detail below with reference to  FIGS.  9   a    ss. A switchover of the coupling between the first and second upper rails  20 ,  21  between the normal operating state and the crash state required for this purpose may thereby be triggered, for example, by an external electrical signal, in particular by a pre-crash signal provided by a central on-board electronic system, by signals from sensors, for example acceleration or force sensors, and by activation of an actuator, but may also be triggered purely mechanically by breaking a breakaway member, for example if the forces acting on the vehicle seat exceed a threshold value which is predetermined by an appropriate design of the mechanical strength of the breakaway member. Examples of such an activation are explained in more detail below. 
     In this context, the components of the longitudinal adjustment device  1  may be designed in such a manner that they can be returned to their initial (home) state or to the normal operating state of the longitudinal adjustment device  1  after a crash by replacing the energy absorber, the breakaway member and other components, for example an actuator or a connecting section  50 , or by transferring a coupling device back to its initial (home) state or to the normal operating state. 
     These operating states of the longitudinal adjustment device  1  are schematically summarized in  FIGS.  2   a - 2   c   . In a normal operating state, when the forces acting on the vehicle seat  8  do not exceed a predetermined threshold value, the second upper rail  21  with the vehicle seat  8  attached thereto and the adjustment element or the first upper rail  20  are rigidly coupled to one another via a coupling device  5 . The vehicle seat  8  thus directly follows an adjustment of the adjustment element or the first upper rail  20 . The vehicle seat  8  can thus be freely adjusted in the adjustment direction x between the front end position shown in  FIG.  2   a    and the rear end position shown in  FIG.  2   b   . In the case of a mechanical longitudinal adjustment, the desired position of the vehicle seat  8  is secured by a mechanical locking unit  22 . In the case of an electrical longitudinal adjustment, the adjustment element  20  and the lower rail  10  are rigidly coupled to each other via a gear unit of the electrical longitudinal adjustment. 
       FIG.  2   c    shows the longitudinal adjustment device  1  in the event of a crash when the forces acting on the vehicle seat  8  have exceeded a predetermined threshold value. In the event of a crash, the energy absorber of the coupling device  5  is coupled or added to the path via which a force acting on the vehicle seat  8  is introduced into the vehicle structure, and the rigid coupling between the second upper rail  21  with the vehicle seat  8  attached thereto and the adjustment element or the first upper rail  20  is released or compensated, so that the energy absorber can dissipate crash energy by deformation, which may result in a certain relative movement between the second upper rail  21  with the vehicle seat  8  attached thereto and the adjustment element or the first upper rail  20 , as schematically indicated in  FIG.  2   c    by the stretching of the coupling device  5 . 
     Thus, two guide systems are combined in a longitudinal adjustment device according to the present invention. On the one hand, a guide system for a classical longitudinal adjustment, for example for a comfort adjustment of the x-position of a vehicle seat in a vehicle, and an additional guide system for an absorber of crash energy in a vehicle seat. For this purpose, a lower rail acting as a guide rail is required for guidance relative to the frame or vehicle body and is permanently installed. A first upper rail or adjustment element is inserted into this lower rail to effect a fixed coupling with the lower rail, for example via a mechanical locking device displaceably guided in a longitudinal direction, via a spindle-gear unit, via a pinion-rack unit or the like. This part of the seat rail pair serves for an adjustment of the comfort position of the vehicle seat. A second upper rail is inserted into the lower rail to which the vehicle seat is attached. Both upper rails are coupled to each other, incorporating an absorber of crash energy or an energy absorber which is activated or added in the event of a crash. 
     The coupling between the two upper rails is not released in a normal operating state, i.e. during driving or adjustment of the comfort setting of the vehicle seat, and remains fixed. In the locked normal operating state, when the second upper rail is rigidly coupled to the first upper rail or the adjustment element, there is no play or only a very slight elastic play between the second upper rail and the first upper rail or the adjustment element, so that the vehicle seat follows an adjustment of the adjustment element or the first rail immediately, without slippage. In the event of a crash, however, the coupling is disengaged or released and the second upper rail, to which the vehicle seat is attached, is guided in the lower rail and can be adjusted over a limited distance relative to the first upper rail  20  or the adjustment element  20 , with deformation of the absorber of crash energy or energy absorber, which is now coupled into the path, to dissipate crash energy. The absorber of crash energy or energy absorber functions in every position of the comfort adjustment of the vehicle seat (especially during a longitudinal adjustment). 
     The energy absorber is integrated between the two upper rails. During driving or adjustment of the comfort setting, the energy absorber is firmly coupled to both upper rails. In the event of a crash, the energy absorber is still firmly coupled to both upper rails, but a relative movement between the two upper rails is released. The energy absorber then converts the crash energy by deformation. The first upper rail or adjustment element remains coupled to the lower rail in the event of a crash and transfers the crash energy into the frame or vehicle structure. In the event of a crash, the second upper rail guides the vehicle seat in a defined direction specified by the lower rail. The threshold for displacement of the two upper rails is not controlled by a lock but by force via the energy absorber itself. The energy absorber is set so that it is not activated under normal operating forces and transmits the operating force and differential forces. At higher forces, e.g. due to a crash, the energy absorber is activated and the rails guide the vehicle seat. 
     By means of additional electronic sensors provided on the vehicle seat or in its immediate vicinity, or also by mechanically sensing setting parameters of the vehicle seat, the activation or coupling-in of the energy absorber can be made dependent on at least one setting parameter of the vehicle seat and/or on at least one parameter relating to the vehicle seat, for example on the current seat position, height or weight of a person sitting on the vehicle seat, on seat occupancy, and on any logical combinations of such parameters. Such a sensing of at least one adjustment parameter of the vehicle seat and/or of at least one parameter concerning the vehicle seat also enables the use of a longitudinal adjustment device according to the present invention in rotatable vehicle seats or in vehicle seats which are designed for autonomous driving operation and which can be adjusted into a reclined or relaxed position retracted very far towards the rear, in which conventional restraint systems, such as seat belts or even airbag systems, cannot be effective. For example, the rotational position of the vehicle seat can be sensed or determined by an electronic sensor or by a mechanical sensor when the vehicle seat is retracted rearward from a range in which restraint systems are still effective. 
     The energy absorber is expediently guided not by means of guide rails but by means of slotted pieces, track guides, tubes or the like. 
     Expediently, the energy absorber is integrated into the path that introduces the force acting on the vehicle seat into the vehicle structure in such a manner that, when it is triggered in the event of a crash, i.e. when the force acting on the vehicle seat exceeds a predefined threshold value, it can absorb crash energy both in the event of a front crash and in the event of a rear crash and dissipate the crash energy by deformation. 
     Due to its simple design with a small mounting space, the longitudinal adjustment device according to the present invention can be integrated in a simple and cost-effective manner into a guide system that is already existing or has been designed. Only a small number of additional components are required for the second guide system (second upper rail  21 ) used for this purpose, which enables a low weight and low additional costs. The longitudinal adjustment system as a whole can be designed in such a manner that the entirety of the two upper rails can be combined modularly with an existing standard lower rail. 
     In the following, a specific embodiment of a longitudinal adjustment device according to the present invention will be described with reference to  FIGS.  3   a - 3   f   . This is shown in accordance with the positions shown in  FIGS.  2   a - 2   c   , in each case in a longitudinal section and in a perspective partial section. Here, the lower rail  10  and the two upper rails  20 ,  21  may be designed as profiles which are U-shaped in cross-section, as disclosed, for example, in WO 2011147991 A1 of the Applicant. 
     As shown in  FIGS.  3   a  and  3   b   , a seat rail pair of a longitudinal adjustment device  1  according to the present invention comprises in each case a lower rail  10  and two upper rails  20 ,  21 , each of which is designed as a profile which is U-shaped in cross section. A threaded spindle  14  is held on the bottom of the lower rail  10  by means of mounting brackets  12 ,  13  in the interior of the respective seat rail, in which a spindle nut of a gear  23  is engaged, which is driven by means of an electric motor (not shown) for longitudinal adjustment of the vehicle seat. While the second upper rail  21 , to which the vehicle seat is attached, is usually relatively long, the first upper rail  20  can be designed to be relatively short in order to optimize the available maximum adjustment travel of the seat rail pair. The two upper rails  20 ,  21  are guided independently of one another on or in the lower rail  10 . 
     A coupling device  5  including an energy absorber is firmly connected to the first and second upper rails  20 ,  21 . The energy absorber may be designed in particular as a tubular hollow profile, as described in more detail below with reference to  FIGS.  4  to  6     e . The energy absorber may in principle also be designed in another manner to provide for a suitable, force-dependent coupling between the two upper rails  20 ,  21 . 
     According to the embodiment example of  FIGS.  4  to  6     e , the energy absorber has a deforming die  51  with an opening defining the deformation of the hollow profile, through which the tubular hollow profile extends. The deforming die  51  is fixedly connected to the second upper rail  21  by means of a connecting section  50 , so that the latter is held fixed relative to the vehicle seat. In principle, however, the deforming die  51  may also be fixed to the vehicle seat, for example to a seat subframe of the vehicle seat, or fixed in a stationary manner relative to the first upper rail  20 . According to  FIG.  3   a   , the deforming die  51  is disposed approximately at a central position on the tubular hollow profile so that the energy absorber is designed to dissipate crash energy both in the event of a rear crash and in the event of a front crash. By selecting the position of the deforming die  51  along the tubular hollow profile, more weight can be given to the design for one of the two crash scenarios, up to the limiting case of a design configured for only one of the two afore-mentioned crash scenarios. 
     Expediently, the tubular hollow profile of the energy absorber  5  is bridged by means of a force-dependent releasable coupling device in a normal operating state. In this case, the coupling device takes on rigid coupling between the first upper rail  20  and the second upper rail  21  with the vehicle seat attached thereto. Only in the event of a crash, when the force acting on the vehicle seat exceeds a predetermined threshold value, is this coupling released so that the two upper rails  20 ,  21  are then coupled to each other only via the tubular hollow profile, and deformable deformation sections  53  of the tubular hollow profile are pressed through the opening of the deforming die  51  by a crash-induced relative movement between the first and second upper rails  20 ,  21 , which results in a deformation inside the deforming die  51  and thus in a dissipation of crash energy. The relative movement between the two upper rails  20 ,  21  continues until end stops terminate this relative movement. 
     Starting from the rear end position of the longitudinal adjustment device  1  shown in  FIGS.  3   a  and  3   b   , when the gear housing  24  rests against the rear mounting bracket  13 , the two upper rails  20 ,  21  can be transferred together, in a normal operating state, to a front end position in which the gear housing  24  rests against the front mounting bracket  12 , as shown in  FIGS.  3   c  and  3   d   , due to the rigid coupling with each other. 
     Finally,  FIGS.  3   e  and  3   f    show the behavior of the longitudinal adjustment device  1  in the event of a rear crash when the vehicle seat has previously been moved to the region of a rear end position. In this case, the rigid coupling between the first upper rail  20  and the second upper rail  21  with the vehicle seat attached thereto is released, for example by releasing the coupling device  5 , so that the two upper rails  20 ,  21  are then only coupled to each other via the tubular hollow profile, which allows a certain relative movement between the two upper rails  20 ,  21  and causes the formation of a gap  25  between the two upper rails  20 ,  21 . Driven by the crash-related forces, the tubular hollow profile with the deformation sections  53  at the front end is pressed through the deforming die  51 , which causes a deformation of the deformation sections  53  in the region in front of the deforming die  51  and results in deformed sections  53 ′ behind the deforming die  51 . Crash energy can be dissipated due to the deformation of the deformation sections  53  to the deformed sections  53 ′. Finally, the relative movement of the two upper rails  20 ,  21  is terminated by end stops or the like (not shown). 
     Details of an energy absorber for converting crash energy in a vehicle by deformation of a deformation member are described below with reference to  FIGS.  4  to  6     e . In this connection,  FIG.  4    shows in a schematic diagram the basic structure of an energy absorber which can be used in particular in a longitudinal adjustment device for vehicle seats in accordance with the present invention, as described above. 
       FIG.  4    relates generally to a scenario in which an energy absorber is coupled between a component  58  fixed to the vehicle body, for example directly to a section of a vehicle body, and a separate component  59 , which in the event of a crash can be adjusted over a relatively short distance in a guided manner relative to the component  58  fixed to the body, with deformation of the energy absorber. The guide required for this purpose is generally designated by reference numeral  54  and may be designed, for example, as a rail system, as a tube system, as a guiding device with slotted pieces or the like. 
     Referring to  FIG.  4   , a tubular hollow profile according to the present invention comprises a preformed section  52  having a first outer profile and a deformation section  53  adjoining the preformed section  52  in the longitudinal direction x and having a second outer profile. A deforming die  51  acting as a deforming member is arranged between the preformed section  52  and the deformation section  53 , the deforming die  51  having an opening through which the tubular hollow profile extends. It is assumed that the deforming die  51  is stationary relative to the component  59 . The inner profile of the opening of the deforming die  51  is formed to correspond to the first outer profile of the preformed section  52 . The second outer profile of the deformation section  53  is formed different to the first outer profile, at least in sections, and extends radially beyond the first outer profile, at least in sections. 
     In the event of a crash, forces act on the separate component  59  which accelerate the separate component  59  together with the deforming die  51 , which is stationary with respect thereto, in the direction of the component  58  fixed to the vehicle body and press the deformable deformation section  53  of the tubular hollow profile through the opening of the deforming die  51 . Because the second outer profile of the deformation section  53  is formed at least in sections different from the first outer profile and extends at least in sections radially to beyond the first outer profile, this results in deformation of the deformation section  53  in the radial direction by bending. The deformable deformation section  53  of the tubular hollow profile is further pressed through the opening of the deforming die  51  under deformation to dissipate additional crash energy between the two components  58 ,  59 . In the process, the component  59  moves closer and closer to the stationary component  58  until finally the deforming die  51  has come close to the stationary component  58  and most of the deformation section  53  has been deformed. In this state, any further movement of the component  59  toward the stationary component  58  is stopped by end stops or the like, which may be provided, for example, in the guide device  54 . 
     In the plan view onto the left end face of the tubular hollow profile shown in  FIG.  5   d   , the profile of the preformed section  52  can be seen to comprise a plurality of side wings  520  or preforms in the radial direction which may be uniformly curved and each of which may be mirror symmetrical in shape. The side wings  520  impart to the tubular hollow profile, at least in sections, an outer profile having an n-number rotational symmetry, where n is an integer and n is greater than or equal to three. In this case, the outer profile of the preformed section  52  corresponds to the inner profile of the opening formed in the deforming die  51 , which defines the deformation of the deformation section  53  as it passes through the opening. 
     In the plan view onto the right end face of the tubular hollow profile shown in  FIG.  5   c   , the profile of the deforming section  53  can be seen to extend radially, at least in sections, beyond the outer profile of the preformed section  52 , so that the deforming section  53  is deformed when it is plunged through the opening of the deforming die  51 . In the illustrated embodiment, the outer profile of the deformation section  53  is formed by a smooth, substantially linearly extending sidewall  530  and a circularly curved sidewall  531  enclosing an approximately three-quarter circle, both the smooth sidewall  530  and the curved sidewall  531  being spaced radially further from the center of the tubular hollow profile than the side wings of the preformed section or in the opening of the forming die  51 . 
     Thus, when the deformation section  53  is forced into the opening of the deforming die  51  in the event of a crash, sections of the smooth side wall  530  and the curved side wall  531  are bent radially inward, forming a profile with side wings arranged in an n-numbered rotational symmetry, corresponding to the outer profile of the preformed section or opening in the deforming die  51 . 
     The inner profile of the deforming die  51  and the outer profile of the deformation section  53  are thereby matched to each other in such a way that the deformation section  53  is preferably formed exclusively by bending into a profile corresponding to the inner profile of the deforming die  51  and the outer profile of the preformed section  52 . 
       FIGS.  6   a - 6   e    show the energy absorber  5  in a state in which most of the deformation section  53  has already been pushed through the opening in the deforming die  51  to form the deformation section  53 ′, the profile of which corresponds to the profile of the preformed section  52  or the inner profile of the opening in the deforming die  51 . 
     According to the present invention, the conversion or reduction of crash energy acting on the vehicle occupant is thereby achieved by radial deformation of a tubular hollow profile. For this purpose, the crash element is forced and/or pushed through a second element in the event of a crash with the aid of the crash energy, for example a tube through a die. When the tube is forced through the die, the tube is radially deformed by bending. In this process, the internal shape of the die defines the forming and final shape of the tubular hollow profile. During the crash, the crash energy is converted into deformation energy, thus reducing the loads on the vehicle occupant. 
     The conversion of crash energy is primarily implemented by deformation/bending, whereby friction is minimized. This makes the conversion of crash energy very controllable and reproducible. Friction, on the other hand, worsens the reproducibility of the conversion of crash energy. By varying the initial tube geometry (for example width, height, diameter, . . . ) and the material used, the maximum energy conversion can be controlled very well according to the invention. 
     The maximum energy conversion can be controlled very well via the degree of deformation (initial geometry compared to final geometry), which is determined by means of the tube geometry and die geometry. 
     By means of the material thickness of the tubular hollow profile, the maximum level of energy conversion can be adjusted very well, even using the same geometry of tube and die. 
     The path of the energy conversion can be controlled very well by means of the length of the tubular hollow profile. 
     Due to the good adjustability of the maximum level of energy conversion, the energy absorber element is very easy to scale and can thus be applied to different crash load scenarios, vehicle types, loads, absorber paths, etc. with little additional effort for the design. 
     Because the conversion of crash energy is primarily based on the mechanism of a deformation of the deformation section, the result is a very smoothly running characteristic curve of the energy conversion. Additional force pulses, as occur in particular with folding crash absorbers and are caused by a strongly fluctuating characteristic curve, can be avoided according to the present invention. 
     The characteristic curve of the conversion of crash energy and the respective force level can be controlled very well via the pre-embossment of the tubular hollow profile. Not only can the maximum height of the characteristic curve be controlled in a simple manner, but also the course of the characteristic curve as a whole. As a result, the energy absorber can be used as a crash energy conversion element for various crash load scenarios. For example, the energy absorber can be designed in a simple manner for different weights, different speeds, different types of vehicles, etc. In principle, the more deformation travel (i.e. tube length) available, the higher the deformation force that can be achieved with the energy absorber. In principle, a soft stop function can also be achieved by means of a sharp rise in the characteristic curve of the energy absorber. 
     The inner contour of the deforming die  51  is expediently designed so that the neutral fiber of the tube cross section are identical before and after deformation. For this purpose, the inner profile of the opening of the deforming die  51  varies in the longitudinal direction x. In particular, it varies in the longitudinal direction x in accordance with a continuous function, wherein a circumferential length of the inner profile of the opening of the deforming die  51  is constant for each position in the longitudinal direction x. This guarantees a uniform deformation of the tubular hollow profile over the complete stroke and guarantees that the neutral fiber of the tube cross-section is not changed. The initial geometry can also be used with a mathematical circular equation for round geometries. 
     In principle, a combination of deformation and tapering of the tubular hollow profile can also be used, in which case the neutral fiber of the tubular cross section before the crash can be different to the neutral fiber of the tubular cross section after the crash. 
     With reference to  FIGS.  7   a  and  7   b   , ways of influencing the characteristic curve of the tubular hollow profile for energy conversion by deformation are described below. In section I, the outer diameter of the preformed section increases linearly with three radial preforms, assuming that the outer diameter of the preformed section corresponds to the inner diameter of the profile in the deforming die right at the beginning. A corresponding linear increase in the characteristic curve of the conversion of crash energy results if the wall thickness of the tubular hollow profile is constant in all areas of section I. 
     In section II, the outer diameter of the preformed section continues to increase linearly, with the outer profile in section II gradually changing from a profile with radial preforms corresponding to the inner profile of the opening in the deforming die to a profile corresponding to the profile of the aforementioned deformation section  53 . This results in a steeper slope of the characteristic curve of the conversion of crash energy in section II. 
     Finally, in section III, the outer diameter of the tubular hollow profile is constant, with the profile of the tubular hollow profile in section III corresponding to the profile of the aforementioned deformation section  53 . This results in slope of the characteristic curve of the conversion of crash energy in section III, which is again smaller. 
     Sections with different pre-embossment are thus provided along the tubular hollow profile, whereby a progressive force-displacement characteristic curve of the tubular hollow profile can be controlled in a targeted manner A similar progressive characteristic curve force vs. displacement can also be generated by increasing the material thickness of the hollow section. 
     As will be readily apparent to those skilled in the art, the application of an energy absorber for converting crash energy is not limited to a longitudinal adjustment device for vehicle seats, but can be used quite generally with any vehicle components mounted in the interior of a vehicle for the purpose of dissipation of crash energy by deformation. Examples include, in particular, vehicle seats, components of a vehicle door, such as a side impact guard, or a knee impact element of a vehicle console. 
       FIG.  8    shows schematic sectional views of further embodiments of an energy absorber according to the present invention. The characteristic curve of the conversion of crash energy of the tubular hollow profile can be suitably adapted by the number of pre-embossments in the radial direction as well as the wall thickness in the pre-embossments. The outer profile of the tubular hollow profile always corresponds to an n-numbered rotational symmetry, where n is an integer and n is greater than or equal to three. 
     In the following,  FIGS.  9   a  and  9   b    will be used to describe a first embodiment of a locking device which is generally suitable for releasably locking a first component relative to a second component which is guided so that it can be displaced in an adjustment direction in a vehicle interior of a motor vehicle. The locking device is designed to be unlocked very quickly in the event of a crash. In particular, the locking device may be associated with an energy-absorbing element arranged in a path through which a force acting on a vehicle seat is introduced into the vehicle structure. In a normal operating condition, when the forces acting on the vehicle seat do not exceed a predetermined threshold, the locking device may provide a rigid coupling between the vehicle seat and the vehicle structure, for example by directly coupling the two upper rails to each other in a seat rail pair, as described above with reference to  FIGS.  2   a  to  3   f   . On the other hand, in the event of a crash, when the forces acting on the vehicle seat exceed the predetermined threshold, the locking device can rapidly release (de-lock) the rigid coupling between the vehicle seat and the vehicle structure to enable a movement of the vehicle seat relative to the vehicle structure, for example between the two upper rails in a seat rail pair, as described above with reference to  FIGS.  2   a  to  3   f   . However, because the energy absorber element is still coupled into the path through which the force acting on a vehicle seat is introduced into the vehicle structure, crash energy can thus be effectively dissipated at an early stage of a crash by deformation of the energy absorber element. 
       FIG.  9   a    shows the locking device  5 ′ in a locked state. It comprises a locking arm  60  having a plurality of locking bodies  62 , which are designed as wedge-shaped teeth, which are arranged at a distance from one another in the adjustment direction x and which, in the locked basic position of the locking arm  60 , engage through openings  28 ,  28 ′, which are formed in a first mounting bracket  27  and a second mounting bracket  27 ′, respectively. The two mounting brackets  27 ,  27 ′ are representative here of the first and second components, respectively, which are intended to be rigidly coupled to one another in a normal operating state and whose coupling is intended to be rapidly released by releasing the locking device  5 ′ in the event of a crash. It shall be assumed for the following, that the second mounting bracket  27 ′ is arranged stationary relative to the vehicle structure, and that the first mounting bracket  27  is guided so that it can be displaced relative to the second mounting bracket  27 ′ or the vehicle structure in the event of a crash. 
     The locking arm  60  is mounted so that it can be pivoted about a pivot axis  61  at a first end of the locking arm  60 . The locking arm  60  is pushed downward by a locking pawl  66  into the locked basic position according to  FIG.  9   a   , as long as a predetermined value of a force acting on the first mounting bracket  27  is not exceeded. When the predetermined value of the force acting on the first mounting bracket  27  is exceeded, on the other hand, the locking arm  60  is released or disengaged so that it can be pivoted about the pivot axis  61  into a released position according to  FIG.  9   b   , in which the engagement of the locking teeth  62  with the associated openings  28 ,  28 ′ of the two mounting brackets  27 ,  27 ′ is released and the first mounting bracket  27  is displaceable relative to the second mounting bracket  27 ′ or the vehicle structure. 
     The locking device  5 ′ further comprises a pivotably mounted intermediate member  68 , which in the illustrated embodiment is formed as a U-shaped profile and is mounted so that it can be pivoted about a different axis  69  than the locking pawl  66 . In principle, it may be sufficient if the threshold value for triggering the locking device  5 ′ in the event of a crash is predetermined by the strength characteristics of a breakaway member  71  which secures the locking pawl  66  or the pivotably mounted intermediate member  68  and prevents their pivoting movement for unlocking the locking pawl  66  as long as a predetermined value of the force acting on the first mounting bracket  27  is not exceeded. For this purpose, it may be sufficient for a plunger  76  mounted on a housing portion  65  of the locking device  5 ′ to permanently bias the pivotably mounted intermediate member  68  against the locking pawl  66  with a high force in a normal operating condition. If the pre-tensioning force becomes too high due to crash forces, the breakaway member  71 , for example a bolt, breaks. After destruction of the breakaway member  71 , the pivotably mounted intermediate member  68  is first pivoted downward about the pivot axis  69  so that it thereby acts on a rear portion of the locking pawl  66  to pivot the locking pawl  66  upward to release a pivotal movement of the locking arm  60  about the pivot axis  61  to release engagement of the locking teeth  62 . 
     To drive this pivoting movement, the front and rear flanks  63   a ,  63   b  of the locking teeth  62  are each inclined at an acute angle with respect to a perpendicular to the locking arm  60 , so that a relative displacement of the first mounting bracket  27 ′ relative to the second mounting bracket  27  drives pivoting of the locking arm  60  to the release position as shown in  FIG.  9   b    because the flanks  63   a ,  63   b  of the locking teeth  62  slide along the edges of the openings  28 ,  28 ′ in the mounting brackets  27 ,  27 ′. 
     In other words, due to the wedging effect caused by the locking teeth  62 , a relative movement of the two mounting brackets  27 ,  27 ′ in the event of a crash, when the breakaway member  71  is destroyed and the locking pawl  66  is released, generates a transverse force and in the x-direction. This causes the locking arm  60  to rotate under its own power. In this case, it may be sufficient if the self-locking of the locking arm  60  is generated by a suitably designed breakaway member. 
     According to a preferred embodiment, the self-locking of the locking arm  60  is generated by the pivotably mounted intermediate member  68 , which is released by activating an electric actuator by destroying the breakaway member  71 . For this purpose, the electric actuator must respond quickly. According to the present invention, an electrically operable actuator is preferred for this purpose, which includes a pyrotechnic gas generator that is triggered when the activation signal is applied. 
     The pyrotechnic gas generator comprises an ignition unit and a solid propellant. The ignition unit is activated by a current pulse from a control unit. This ignites the solid propellant, which may be in tablet form. The resulting hot gas flows through a metal filter from the gas generator into a gas-tight chamber, which drives a plunger  76  that destroys the breakaway member  71 . Such pyrotechnic gas generators are sufficiently well known from airbag systems. 
     As an alternative, a gearbox, lifting solenoid, shape memory actuator, piezoelectric actuator or the like may be used to release the locking device  5 ′. As an alternative to the pyrotechnic drive, a motor or a pneumatic drive could be used. 
       FIG.  10    shows a specific mounting situation of such a locking device  5 ′ according to  FIGS.  9   a  and  9   b    in a longitudinal adjustment device for vehicle seats. First of all, additional components for connecting the vehicle seat to the seat rail pair  2  are shown, including two mounting brackets  85  which are each attached to the second upper rails  21  and to which the vehicle seat is attached. A groove-type guide  86  for adjusting the angle of inclination of the backrest is shown at the rear end of the mounting brackets  85 . The two mounting brackets  85  are rigidly connected to each other via transverse members  87 ,  88 . Locking units  5 ′ as shown in  FIGS.  9   a  and  9   b    are provided on the rear transverse member  88  on the inside of the longitudinal adjustment device  1 . When triggered in the event of a crash, these release the rigid coupling between the two upper rails  20 ,  21  to permit a relative movement between the two upper rails  20 ,  21 . For the dissipation of crash energy, an energy absorber is coupled into the path that introduces the force acting on the vehicle seat into the vehicle structure via the first upper rail  20  and the lower rail  10 , as described above with reference to  FIGS.  4  to  8   . The energy absorber is provided on the inner side of a carrier  55  and dissipates energy by deformation in the event of a crash, as described above. The engagement of locking teeth of the locking device  5 ′ in associated detent openings is released by activating a pyrotechnic gas generator  75  of the locking device  5 ′ to release the relative movement between the two upper rails  20 ,  21  with the energy absorber interposed. 
       FIGS.  11   a - 11   c    show a further embodiment of a locking device  5 ′ according to the present invention. Here, the pyrotechnic actuator  75  is secured to a first housing portion  65  formed by two outwardly bent retaining arms  640  forming a cylindrical receiving opening and a rectangular receiving space, wherein a gap or retaining groove  641  is formed between the rectangular receiving space and the cylindrical receiving opening in which a clamping ring  642  securely retains a radial projection of the pyrotechnic actuator  75 . The pyrotechnic actuator  75  itself is secured to the rectangular receiving space of the housing section  65  by means of retaining clips  650 . 
     In the normal operating condition shown in  FIG.  11   a   , when the prevailing forces do not exceed a predetermined threshold, one end of the pivotably mounted locking pawl  66  is in direct contact with the front end of the pyrotechnic actuator  75 . Rotational movement of the locking pawl  66  is prevented by a locking pin  71 , designed as a breakaway member, which is secured in openings on the housing section  64 . At its opposite other end, the locking pawl  66  is mounted for rotational movement about axis  67 . The other end of the locking pawl  66  pushes the pivotably mounted locking arm  60  downward so that the locking teeth  62  engage in associated detent openings  28 ,  28 ′ in the manner described above to block a relative displacement between the two brackets  27 ,  27 ′. 
     In the event of a crash, when the prevailing forces exceed a predetermined threshold, the pyrotechnic actuator  75  is electronically activated so that the plunger is propelled forward by ignition of the ignition unit of a pyrotechnic gas generator, causing the locking pawl  66  to first destroy the locking pin  71  and then the locking pawl  66  to further pivot about the axis  67  until finally the other end of the locking pawl  66  releases the locking arm  60  and no longer pushes it downward. The chamfered front and rear flanks  62   a ,  63   b  of the locking teeth  62  then actively drive further upward pivoting of the locking arm  60  due to the onset of relative displacement between the two mounting brackets  27 ,  27 ′ in cooperation with edges of the associated detent openings  28 ,  28 ′ until finally the engagement of the locking teeth  27 ,  27 ′ with the associated detent openings  28 ,  28 ′ is fully released and the release position shown in  FIG.  11   b    is reached. 
     The shaping of the locking teeth  62  is designed to more effectively drive the upward pivoting of the locking arm  60  into the release position. As can be seen from  FIGS.  11   a - 11   c   , the closer the locking teeth  62  are arranged to the rear end of the locking arm  60  with the pivot axis  61  located there, the more they are bent backward. Thus, the locking teeth  62  are wedged into the associated detent openings  28 ,  28 ′ with different angles of inclination. While the angle of inclination of the first locking tooth  62 —as viewed from the pivot axis  61 —at which it is inclined rearwardly in the direction of the pivot axis  61  is greatest and is about 20 degrees in the illustrated embodiment, this angle of inclination becomes smaller and smaller the further apart the respective locking tooth  62  is from the pivot axis  61 . As can be seen from  FIG.  11   a   , the foremost locking tooth  62  spaced furthest from the pivot axis  61  engages almost perpendicularly in the associated detent openings  28 ,  28 ′. The opening widths of the associated detent openings  28 ,  28 ′ are suitably adapted to this geometry of the locking teeth  62 . As can be further seen from  FIGS.  11   a - 11   c   , the lengths of the locking teeth  62  are also different. More specifically, the length of the first locking tooth  62 —as viewed from the pivot axis  61 —is smallest and the length of the locking teeth  62  becomes longer and longer the further apart the respective locking tooth  62  is located from the pivot axis  61 . The forward free ends of the locking teeth  62  enclose an envelope E that is curved with a progressively decreasing pitch starting from the region of the pivot axis  61  and progressively away from the locking arm  60 . 
     In a locking device  5 ′ according to the present invention, it is important to rapidly destroy or break the breakaway member in order to release the locking of the locking device  5 ′, which can be achieved in particular by means of a pyrotechnic actuator. Due to the inertial force, the vehicle seat generates its own rotary drive for the locking teeth during a crash, which locking teeth are comb-like and beveled, and thus no external rotary drive is required to pivot the locking arm. Overall, the system enables a very short opening time. 
     A locking device  5 ′ according to the present invention can be manufactured in a simple and inexpensive manner using stamped parts and/or injection molded parts. The two embodiments described above can also be used in a belt integral seat without major modifications, and thus both locking devices  5 ′ can also accommodate higher crash loads. 
       FIGS.  12   a - 12   c    show a specific mounting situation of such a locking unit  5 ′ according to  FIGS.  11   a - 11   c    in a longitudinal adjustment device for vehicle seats. The locking units  5 ′ are provided on the rear transverse member  88  on the inside of the longitudinal adjustment device  1 . When triggered in the event of a crash, these release the rigid coupling between the two upper rails  20 ,  21  to enable a relative movement between the two upper rails  20 ,  21 . For the dissipation of crash energy, an energy absorber is coupled in the path that introduces the force acting on the vehicle seat into the vehicle structure via the first upper rail  20  and the lower rail  10 , as described above with reference to  FIGS.  4  to  8   . The energy absorber is provided on the inner side of a carrier  55  and dissipates energy by deformation in the event of a crash, as described above. The engagement of locking teeth of the locking device  5 ′ in associated detent openings is released by activating a pyrotechnic gas generator  75  of the locking device  5 ′ to release the relative movement between the two upper rails  20 ,  21  with the interposition of the energy absorber. 
     As already explained above, the release of a locking device for a vehicle seat can in principle be controlled purely mechanically. Thus, it may be sufficient to determine the release behavior of the locking device purely mechanically by means of the mechanical characteristics of the aforementioned breakaway member and its integration into the path via which a force acting on a vehicle seat is introduced into the vehicle structure. In addition, provisions may be made to release a triggering of the locking device by releasing the pivoting movement of the aforementioned locking arm only if setting parameters of the vehicle seat, which are sensed purely mechanically, are within a predetermined range. Examples of such setting parameters may be: a position of the vehicle seat in the longitudinal direction of the seat rail pair (for example, if the vehicle seat has been reclined far backward into a relax or rest position for an autonomous driving application in which personal restraint systems, such as airbags or seat belts, are no longer effective, it may be advantageous for the locking device not to be released, so that the rigid coupling of the two upper rails remains in place and the vehicle seat can be moved more quickly back into the area in which personal restraint systems are effective), an angle of inclination of the backrest of the vehicle seat (if the backrest is inclined too far backwards, for example, it can be advantageous if another securing system first raises the backrest again before, if applicable the aforementioned locking device is triggered), an angle of rotation of the vehicle seat (if the vehicle seat is twisted sideways or rotated backwards by 180 degrees, it may be advantageous if the aforementioned locking device is not triggered but other securing systems are activated instead). Such adjustment parameters of the vehicle seat can in principle be sensed purely mechanically, for example by means of control cams or depressing members or by means of area-dependent latching or release of securing bolts or the like, the respective position of which is either directly coupled to the breakaway member or blocks an adjustment of an element that destroys a breakaway member. 
     Preferably, however, a locking device is released under the control of an electronic system, which requires electrical or piezoelectric actuators, in particular also a pyrotechnical gas generator, which releases an unlocking of the locking device by destroying a breakaway member or rapidly adjusting a component. For this purpose, the locking device may receive in particular a pre-crash signal from the on-board electronics or an activation signal from a central processor of the vehicle&#39;s on-board electronics, which triggers the electrical actuator of the locking device. 
     The triggering of the locking device can also be influenced or controlled by output signals from sensors, which is explained below by way of example with reference to  FIG.  13   , which illustrates a system for controlling a locking device  5  for a vehicle seat  8 , which is designed as described above. In this system, one or more sensors  102   a - 102   c  are arranged in the vehicle seat  8  and/or in its surroundings, for example optical, electronic or magnetic sensors, which sense at least one setting parameter of the vehicle seat  8  or a parameter concerning the vehicle seat  8 , and output a signal corresponding to the setting parameter to a control device  100 , for example to a processing unit, which may also be integrated in the on-board electronics and logic. On the basis of the respective signal output from an electronic sensor, the control device  100  then generates an activation signal that is output to the electric actuator of the locking device  5  via a line  101  to trigger the unlocking of the locking device  5 . 
     In the calculation of the activation signal, on the one hand, the force acting on the vehicle seat  8  can be included. Thus, the activation signal is output by the control device  100  only when the force acting on the vehicle seat  8  exceeds a predetermined value. However, the generation of the activation signal may additionally be dependent on at least one output signal of the sensors  102   a - 102   c  associated with the vehicle seat  8 . In particular, the control device  100  may also logically associate output signals of the sensors  102   a - 102   c  with each other and further may also logically associate them with the value of the force acting on the vehicle seat  8 . 
     For example, if one of the sensors  102   a - 102   c  senses that the vehicle seat is displaced to a far forward position, i.e., very far forward into the immediate vicinity of a front airbag, it may be advantageous not to trigger an unlocking of the locking device to prevent the vehicle seat from being displaced even further forward toward the front airbag and a vehicle dashboard after an unlocking of the locking device. Or, if one of the sensors  102   a - 102   c  senses that the vehicle seat has been reclined far rearward into a relax or rest position for an autonomous driving application, for example, in which personal restraint systems, such as airbags or seat belts, are no longer effective, it may be advantageous to not trigger an unlocking of the locking device so that the rigid coupling of the two upper rails remains in place and the vehicle seat can be reclined more quickly into the range in which personal restraint systems are again effective. Or, if one of the sensors  102   a - 102   c  senses that the backrest has been reclined too far backward, for example, it may be advantageous for another restraint system to first recline the backrest before the aforementioned locking device is triggered, if applicable. Or, if one of the sensors  102   a - 102   c  senses on the basis of an angle of rotation of the vehicle seat that the vehicle seat is rotated laterally or rotated 180 degrees backward, it may be advantageous not to trigger an unlocking of the locking device but to activate other securing systems. 
     The sensors  102   a - 102   c  can be used to sense a variety of different adjustment parameters of the vehicle seat  8  and/or parameters concerning the vehicle seat  8 . Examples include: a position of the vehicle seat  8  in the adjustment direction x, an angle of inclination of the backrest  81  of the vehicle seat  8 , an adjustment of the height of a seat portion  80  of the vehicle seat  8 , an angle of inclination of the seat portion  80  of the vehicle seat  8 , a seat occupancy, the weight of a vehicle occupant sitting on the vehicle seat  8 , a height of the vehicle occupant, parameters regarding the geometry of the vehicle interior in the vicinity of the vehicle seat  8 , the setting of the height and/or angle of inclination of a headrest of the vehicle seat  8 . 
     A locking device, as described above, is in principle suitable for many other applications in vehicles. Examples are as follows: In the case of a longitudinal adjustment for a seat unit, releasing a movement of a pretensioned seat unit can take place in the event of a pre-crash in order to quickly achieve a directed seat position in the x-direction, in which person restraint systems, e.g. an airbag, are then effective. In the case of an active head restraint, which is preloaded with a spring, a rapid adjustment of the head restraint in the x- and/or z-direction can be accomplished by triggering the locking device. 
     In combination with an energy absorber, as described above, further advantageous effects can be achieved. Examples include: The locking device can release a rapid rotational movement on the seat pan of a vehicle seat during a crash to deform a component or assembly with an energy absorber element. In an adjustment device for adjusting the angle of inclination of a backrest or backrest head, the locking device may release a rapid rotational movement at the backrest head during a crash to deform a component or assembly with an energy absorber element. 
     As will be readily apparent to the skilled person studying the foregoing description, a seat rail pair as described above, an energy absorber with a tubular hollow profile as described above, and a locking device as described above can be integrated into a vehicle seat unit, if necessary together with an electronic control system of an appropriately design, so that crash energy can be effectively dissipated with deformation of the energy absorber when a predetermined value of the force acting on the vehicle seat is exceeded. This can further increase safety for vehicle occupants. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  longitudinal adjustment device 
           2  seat rail 
           5  coupling device with energy absorber 
           5 ′ releasable coupling device 
           8  vehicle seat 
           10  lower rail 
           11  vehicle floor 
           110  guide channel in vehicle floor 
           12  front mounting bracket 
           13  rear bracket 
           14  threaded spindle 
           20  first upper rail 
           200  opening 
           21  second upper rail 
           22  releasable locking device 
           23  gearbox/spindle nut 
           24  gearbox housing 
           25  gap 
           27  first mounting bracket 
           27 ′ second mounting bracket 
           28  opening in first mounting bracket 
           28 ′ opening in second mounting bracket 
           50  connecting section 
           51  deforming die 
           510  deforming section of deforming die  51   
           52  preformed section of hollow profile 
           520  side wing of preformed section  52   
           53  deformation section of hollow profile 
           530  smooth side wall 
           531  curved side wall 
           53 ′ deformed section of hollow profile 
           530 ′ side wing of deformed section  53 ′ 
           54  guiding device 
           55  carrier for energy absorber 
           56  latching opening in carrier  55   
           56 ′ locking body 
           58  body fixed component 
           59  second component 
           60  pivoting locking arm 
           61  pivot axis 
           62  locking tooth 
           63   a  front flank of locking tooth  62   
           63   b  rear flank of locking tooth  62   
           64  first housing section 
           640  retaining arm 
           641  retaining groove 
           642  clamping ring 
           65  second housing section 
           650  retaining clips 
           66  locking pawl 
           67  pivot axis of locking pawl  66   
           68  rotatable intermediate member 
           69  pivot axis of rotatable intermediate member  68   
           70  guide recess 
           71  breakaway pin 
           72  receptacle of breakaway pin  71   
           75  pyrotechnic actuator 
           76  plunger 
           80  seat part 
           800  seat pan 
           801  lateral support 
           802  adjustment fitting for inclination of backrest 
           81  backrest 
           82  mounting bracket/seat base 
           85  mounting bracket 
           86  adjustment guide for inclination of backrest 
           87  transverse member 
           88  transverse member 
           89  motor/gear unit for adjustment of inclination of backrest 
           90  swivel axis for adjustment of inclination of backrest 
           100  central processing unit 
           101  signal line 
           102   a - 102   c  sensor 
         x adjustment direction 
         E envelope