Locking device for a vehicle seat

[0002] This is a continuation of PCT/EP02/07770, which was filed Jul. 12, 2002, published in German, and is entirely incorporated herein by reference.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] The invention is explained in greater detail below with reference to an exemplary embodiment which is illustrated in the drawings, in which:

[0010] FIG. 1 shows a partial view (illustrated partially in section) of a latching fitting having a locking device according to the invention, and

[0011] FIG. 2 shows a schematic illustration of a vehicle seat.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.