Abstract:
A locking device for a vehicle seat, in particular a locking device in an adjuster of a motor vehicle seat, has at least two locking elements ( 12, 15 ) which can be moved relative to each other and can be brought into engagement where they are secured by at least one securing element ( 23 ) which is mounted in a manner such that the securing device can pivot about a rotational axis ( 25 ). The securing element ( 23 ) is mounted in a balanced manner.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation of PCT/EP02/07770, which was filed Jul. 12, 2002, published in German, and is entirely incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a locking device for a vehicle seat, in particular a locking device located in an adjuster of a motor vehicle seat, having at least two locking elements which can be moved relative to each other and can be brought into engagement, with the engagement being maintained by at least one securing element which is mounted for pivoting about a rotational axis. 
     In a known locking device of this type for locking a fitting of a vehicle seat having a backrest which can pivot freely, there is a pivotable detent pawl for locking the fitting upper part, a control cam connected in a rotationally fixed manner to the detent pawl, an intercepting element for supporting the detent pawl in the event of a crash, and a spring-loaded clamping element, which acts on the control cam, for clamping the detent pawl relative to the fitting upper part. The intercepting and clamping elements, which are for acting as securing elements, are mounted pivotably and are provided with suitable active surfaces. In practice, some things remain to be desired, for example with regard to the outlay involved in production. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the present invention is the provision of a locking device for a vehicle seat, in particular a locking device located in an adjuster of a motor vehicle seat, having at least two locking elements which can be moved relative to each other and can be brought into engagement where they are secured by at least one securing element that is mounted, in a balanced manner, for pivoting. 
     By virtue of the securing element being mounted in a balanced manner, i.e. the rotational axis of the securing element runs through its center of gravity, mass forces of inertia do not, in the event of a crash, produce a resulting torque which would cause a moment of momentum, i.e. a pivoting movement, of the securing element. As a result, an acceleration of the securing element, which could have an opening effect on further securing elements via connecting means, is avoided, with the result that the securing element behaves in a manner which is neutral in terms of acceleration. In the case of the known locking devices having securing elements which are mounted outside the center of gravity, the above-mentioned problems may occur, particularly if the securing elements are connected together, and the problems have to be prevented by appropriate, dimensionally accurate machining of the components. 
     At least one section of material is preferably integrally formed on the securing element as a balancing weight. This integral design is neutral in terms of outlay in the case of production. In order to avoid stresses and fractures if overloaded, the section of material may be of lug-like design with rounded or continuous transitions. For a simpler balancing of masses, two sections of material are preferably provided at the same distance from the rotational axis, specifically, as a rule, with respect to the rotational axis, on the side facing away from the active surface of the securing element. A flat design of the securing element not only saves structural space, but also simplifies the balancing. Preferably taken into consideration as the balanced securing element are clamping and/or intercepting elements which are suitable for clamping and, in the event of a crash, for supporting locking elements designed as pivotable detent pawls. 
     The locking device according to the invention can be used for various adjusters, i.e. both for rotational adjusters, such as, for example, fittings of vehicle seats having a backrest which can be varied in inclination and/or can pivot freely, and also for linear adjusters, such as, for example, longitudinal adjusters or vertical adjusters in combination with diagonal struts. The locking device according to the invention can also be used for the locking of various positions of a foldable vehicle seat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in greater detail below with reference to an exemplary embodiment which is illustrated in the drawings, in which: 
     FIG. 1 shows a partial view (illustrated partially in section) of a latching fitting having a locking device according to the invention, and 
     FIG. 2 shows a schematic illustration of a vehicle seat. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A latching fitting  1  for a vehicle seat  3  is provided with a fitting lower part  5  which is fixed on the seat substructure and has two essentially flat plates which are joined together and define a structural space of the fitting lower part  5 , and with a flat fitting upper part  8  which is fixed to the backrest structure. The fitting upper part  8  is at least partially arranged within the structural space of the fitting lower part  5  and can be rotated relative to the fitting lower part  5  about a backrest bolt  10 . The vehicle seat  3  has two mirror-inverted latching fittings  1  which support the backrest of the vehicle seat  3  in a manner such that it can be adjusted in inclination and pivoted. For a locking device  11 , a toothed rim  12 , which is curved around the backrest bolt  10 , is provided on the fitting upper part  8 , in the region facing away from the backrest, and a detent pawl  15 , which is arranged within the structural space and is mounted pivotably on a pawl bearing bolt  13 , is provided on the fitting lower part  5 . The detent pawl  15  and the toothed rim  12  are for interacting by toothed engagement depending on the relative position of the fitting parts  5  and  8 . 
     A control cam  17  which, firstly, interacts with a control disc  18  of the fitting upper part  8 , which disc is arranged around the backrest bolt  10 , and, secondly, interacts with a clamping eccentric  23 , is provided on the detent pawl  15  in a parallel plane. The essentially flat clamping eccentric  23  is mounted pivotably on a bearing bolt  25  of the fitting lower part  5  on that side of the detent pawl  15  which faces away from the toothed rim  12 . In order to interact with the control cam  17 , the clamping eccentric  23  has a clamping surface  23 ′ which is curved eccentrically with respect to the bearing bolt  25 . In the locked state of the latching fitting  1 , a spring (not illustrated) presses the clamping eccentric  23  by way of the clamping surface  23 ′ against the control cam  17 , with the result that the detent pawl  15  is pressed with its teeth into the toothed rim  12  and is therefore secured when in use. 
     As a securing means in the event of a crash, an essentially flat intercepting element  27  is provided. The intercepting element  27  is likewise mounted in a spring-loaded and pivotable manner on the bearing bolt  25  in the same plane as the detent pawl  15 , i.e. in a plane parallel to the clamping eccentric  23 . The intercepting element  27  is normally arranged at a small distance from the detent pawl  15 . In the event of a crash, a torque acts on the fitting upper part  8  which acts on the detent pawl  15  and, if appropriate, presses back the clamping eccentric  23 . After a minimal pivoting movement, the detent pawl  15  is supported on the intercepting element  27  in such a manner that the toothed engagement between the detent pawl  15  and the toothed rim  12  is maintained. 
     An unlocking bolt  29 , which engages through a slotted guide  31  of the clamping eccentric  23 , is fitted on the intercepting element  27  parallel to the bearing bolt  25 . The intercepting element  27  and the clamping eccentric  23  are connected via the slot and tenon guide formed in this manner. In order to unlock the latching fitting  1  when it is in use, the intercepting element  27  is pivoted back via the unlocking bolt  29  counter to its spring loading, in which case, after a dead movement via the slot and tenon guide, it pulls along the clamping eccentric  23 , i.e. opens counter to its spring loading. During the further course of this movement, the intercepting element  27  carries along the detent pawl  15 , with the result that the latter is opened and the latching fitting  1  is unlocked. 
     In order, in the event of a crash, to keep the opening moment on the clamping eccentric  23  as small as possible, the clamping eccentric  23  is mounted in a balanced manner on the bearing bolt  25 . For this purpose, the clamping eccentric  23  has, at the same distance from the bearing bolt  25 , two integrally formed, lug-like sections of material  33  which are arranged, with respect to the bearing bolt  25 , on that side of the clamping eccentric  23  which faces away from the clamping surface  23 ′. On the side situated radially further outward, the sections of material  33  merge with a continuous transition into the clamping eccentric and then into one another, while on the other side a step-like, rounded transition is provided. The integral design together with the clamping eccentric  23  simplifies the production of the sections of material  33 . Owing to the selected dimensions of the sections of material  33 , the center of gravity of the clamping eccentric  23  lies precisely on the rotational axis of the clamping eccentric  23 . In the event of a crash, the inertia of the clamping eccentric  23  does not cause a torque to be produced nor does it cause the latter to be transmitted to the intercepting element  27  via the connecting means. The intercepting element  27  is preferably balanced in a corresponding manner.