Locking device, in particular for a vehicle seat

A locking device, in particular for a vehicle seat, includes a latch (24) and a counter element that interacts for locking. A bearing bush (30), a release element (32) that is rotationally mounted inside the bearing bush (30) and a catch element (34) for reinforcing the latch (24) in the event of a crash are provided with the catch element (34) being mounted in a rotationally secure manner on the release element (32) or being embodied as one piece with the release element. A tightening element (36), for securing the locked latch (24) during normal operation, is arranged in an axial manner adjacent to said catch element (34) and is mounted in a pivotable manner and is prestressed in such a manner that it is pivotably mounted on the outside on the bearing bush (30).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. States National Phase application of International Application PCT/EP2009/000160 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2008 008 936.2 filed Feb. 8, 2008, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a locking device, in particular for a vehicle seat, comprising a latch and a counter element, which interact for locking.

BACKGROUND OF THE INVENTION

A fitting comprising a locking device of this type for a two-door motor vehicle is known from DE 10 2006 044 489 A1, which is used to permit access to the rear by means of the backrest freely pivoting in the forward direction, and to provide different inclination adjustments of the backrest for use by a passenger. For the free pivoting, the locking device is unlocked by a release element being rotated. In order to prevent undesired pivoting-back of the backrest, for example when the cushioning in the transition region between the backrest and the seat part is too great, a securing of the backrest is provided in the freely pivoted position.

SUMMARY OF THE INVENTION

The object of the invention is to improve a locking device of the aforementioned type.

According to the invention, a locking device is provided with a latch, a prestressed clamping element for securing the locked latch normally and a catch element for reinforcing the latch in the event of a crash. For unlocking the latch, a release element is provided, the rotation thereof about its own axis preferably pivoting the catch element away from the latch. The clamping element is preferably coupled so that it may be carried along with free travel, for example by means of a slotted pin guide, so that it is ultimately also pivoted away from the latch by the rotating release element, thus unlocking said latch. A bearing bush is provided for mounting the release element and the clamping element. The mounting of the release element according to the invention inside the bearing bush and the clamping element on the outside on the bearing bush has the advantage that, at the start of the rotation of the release element, the clamping element is not already inadvertently carried along, for example due to friction but, for example, only when the free travel has been passed. Moreover, if the clamping element were to be pivoted away in the event of a crash, the catch element would be able to remain unaffected in its position.

The locking device is preferably a component of a fitting for a vehicle seat having a seat part and a backrest, the fitting preferably being provided with an adjustment fitting for the inclination adjustment of the backrest relative to the seat part, a freely-pivoting unit for the centric free-pivoting of the backrest from at least one position of use into a freely pivoted position, which is triggered by means of a freely-pivoting operating element, a fitting lower part which may be connected to the seat part and which carries the adjustment fitting and a fitting upper part associated with the freely-pivoting unit, which may be connected to the backrest and which in the position of use is locked by means of the locking device.

The latch is preferably pivotably articulated to the fitting upper part and locked to a detent plate of the freely-pivoting unit. Preferably, a cover is provided which is connected to the fitting upper part and covers the locking device. The adjustment fitting is connected with its two fitting parts which are rotatable relative to one another, on the one hand, preferably fixedly to the detent plate and, on the other hand, fixedly to the fitting lower part. Thus the freely-pivoting unit may be produced and tested as a pre-assembled sub-assembly.

Preferably, a securing latch is provided which secures the fitting upper part in the freely-pivoted position of the backrest to the fitting lower part. The securing latch is preferably able to be opened automatically by means of the longitudinal adjuster of the vehicle seat, in particular when the longitudinal adjuster moves the vehicle seat into the previously set longitudinal seat position, which is recognized by a memory device. Moreover, the securing latch may be opened manually by means of the freely-pivoting operating element, in particular in specific situations when, for example, the previously set longitudinal seat position is no longer reached. A freely-pivoted position, independent of the set inclination of the backrest, results when securing the fitting upper part to the fitting lower part.

The securing latch is preferably pivotably articulated to the fitting upper part and cooperates, for the purpose of securing, with a stop on the fitting lower part. This simplifies the coupling to the longitudinal adjuster. The stop preferably also defines the inclination adjustment, for example by it being arranged within a recess of the detent plate. The dual function dispenses with a further component. The securing latch in the position of use preferably bears against a component of the freely-pivoting unit, for example the detent element or a switching ring, which is advantageous for the freely-pivoting unit as a pre-assembled sub-assembly. During the free pivoting of the backrest, when reaching the stop the securing latch may pivot slightly upwards with the further pivoting movement of the backrest and slide along the underside of the stop, until it engages behind the stop after passing the stop. However, other possibilities for the cooperation of the securing latch and the stop are also possible. The securing latch and the stop preferably cooperate outside the self-locking region. A pretensioning may ensure a non-positive cooperation. Thus it is respectively ensured that the securing latch opens by a relative movement of the fitting upper part and stop and/or above a marginal force.

The securing latch is preferably secured by an operating lever, which is preferably prestressed. The securing may take place positively or non-positively. The securing latch secured by the operating lever may be opened, by the cooperation of the securing latch and the operating lever being canceled, for example by the operating lever being pivoted away from the securing latch. This may take place automatically in the presence of specific conditions, for example in a specific longitudinal seat position, so that the backrest may then be pivoted back into its initial position.

By means of a rotatable switching ring which during the actuation of the freely-pivoting operating element, cancels the cooperation of the securing latch and the operating lever, the securing operation may be manually terminated. The rotation of the switching ring is, for example, effected by the catch element, for which said two components preferably have projections with suitably higher sides. The rotated switching ring preferably acts by means of a switching contour on the operating lever, in order to remove said operating lever from the securing latch.

The invention may be used preferably in longitudinally adjustable vehicle seats of two-door motor vehicles with central free pivoting of the backrest, but also may be used for other vehicle seats. With a use of the fitting according to the invention for activating the so-called “easy entry function”, in which apart from a free pivoting of the backrest a movement of the vehicle seat takes place, the backrest may be pivoted back exactly when the previously set longitudinal seat position is reached.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in particular, a vehicle seat1for a two-door motor vehicle has, for the inclination adjustment, i.e. the slow, small angular alteration between a plurality of positions of use, and free pivoting, i.e. the rapid, large angular alteration from a position of use into a freely pivoted position as a specific position of non-use, of its backrest2relative to its seat part3, one respective fitting5on both of its sides. On the outside of the vehicle seat1, for the inclination adjustment function on one of the fittings5, a handwheel7is provided and between both fittings5a shaft connected to the handwheel7, whilst for the free-pivoting function a freely-pivoting operating element8, for example a hand lever, is movably attached to the backrest2.

Each fitting5comprises a fitting lower part9which serves for fastening the fitting5to the structure of the seat part3(“fixed to the seat part”), a backrest inclination adjustment fitting, denoted in short hereinafter as an adjustment fitting11, and a freely-pivoting unit12which in turn has a fitting upper part14, which is used for fastening the fitting5to the structure of the backrest2(“fixed to the backrest”).

The adjustment fitting11is formed in terms of structure as a disc-shaped unit, as is disclosed for example in DE 101 05 282 B4 (corresponding to U.S. Pat. No. 6,799,806), the disclosure thereof being expressly included in the invention. The adjustment fitting11has two fitting parts which may be rotated relative to one another and are held together by means of a clamping ring in the axial direction. In the embodiment, the adjustment fitting11is configured as a geared fitting, i.e. the two fitting parts of the adjustment fitting11are connected to one another in transmission by means of an eccentric epicyclic gear—which is self-locking here—and which in the present case permits a securing without clearance of the two fitting parts of the adjustment fitting11, and for the stepless adjustment forces a relative rotation of the two fitting parts of the adjustment fitting11with a superimposed wobble motion. The path of this wobble motion might be denoted as a wobble loop. Such a geared fitting is, for example, disclosed in DE 44 36 101 A1 (corresponding to U.S. Pat. No. 5,634,689), the disclosure thereof being expressly included in the invention. The rotation of the handwheel7drives the geared fitting. However, other geared fittings and—in theory—also detent fittings may also be used as adjustment fittings11. In the latter case, a small rotation of the handwheel7or a lever provided as an alternative unlocks the detent fitting. The adjustment fitting11is connected by one of its two fitting parts and the clamping ring fixedly to the fitting lower part9, i.e. one of the two fitting parts of the adjustment fitting11is fixed to the seat part. To this end, the fitting lower part9has a fork-shaped receiver for the adjustment fitting11.

The freely-pivoting unit12has an—approximately annular—detent plate16, relative to which the fitting upper part14is rotatably mounted about an axis A. The axis A and its position within the vehicle seat1define the directional information used in the present case. As the axis A—possibly apart from the wobble motion—coincides with the central axis of the adjustment fitting11, in the present case central free pivoting is present. A stop17is fastened to the fitting lower part9and projects therefrom axially. The detent plate16has on one part of its periphery a recess16aoffset radially to the inside, defined in each case by a step, within which the stop17is arranged. By the cooperation of the stop17with the steps of the detent plate16, the angle for the inclination adjustment of the backrest2is defined. The detent plate16(and thus the freely-pivoting unit12) is fixedly connected to that of the two fitting parts of the adjustment fitting11which is not fixed to the seat part. The connection of the freely-pivoting unit12to the adjustment fitting11takes place, for example, by laser welding.

For the mounting of the fitting upper part14, the detent plate16in the present case has a collar projecting axially relative to the axis A, on which the fitting upper part14is rotatably mounted. The fitting upper part14also has a collar which projects towards the detent plate16, so that between the detent plate16and the fitting upper part14a constructional space is present. A retaining disk18serves as axial securing of the fitting upper part14. The retaining disk18configured as an annular disk is connected to the detent plate16after positioning the fitting upper part14on the collar of the detent plate16, said retaining disk engaging behind the fitting upper part14. A cover20connected to the fitting upper part14defines, on the one hand, a constructional space between itself and the fitting upper part14projecting upwards over the detent plate16. On the other hand, the lower edge of the cover20is configured as a retaining clamp, and engages over the detent plate16, possibly by the interposition of a slider, for example made of plastics. The cover20is thus used as further axial securing of the fitting upper part14.

On the fitting upper part14by means of a bearing pin22a latch24is pivotably mounted, which may be locked to the detent plate16. The bearing pin22parallel to the axis A defines at the same time the pivoting motion of the fitting upper part14to the rear, and namely both normally and also in the event of a (rear) crash, by bearing against a first detent stop26of the detent plate16. For locking the latch24and for limiting the pivoting motion of the fitting upper part14to the front in the event of a (front) crash, a second detent stop28is provided in the radial extension of the latch24on the detent element16. The latch24is locked to the detent plate16, on the one hand, by being supported by means of the bearing pin22on the first detent stop26and, on the other hand, by bearing with its free end on the second detent stop28without clearance. To this end, the bearing takes place at an angle outside the self-locking region. An alternative support on the first detent stop26may be implemented by means of a shaping or the like of the fitting upper part14. Both detent stops26and28are formed in the present case on the detent plate16, i.e. configured integrally therewith. The bearing pin22is configured as an eccentric pin, i.e. it is rotatably mounted in the fitting upper part14about an axis which is offset relative to the pivot axis of the latch24, relative to said fitting upper part. For compensating for production tolerances, the bearing pin22is adjusted and fixed such that the latch24bears with maximum latch engagement on the second detent fitting28.

In the fitting upper part14a bearing bush30is preferably located fixedly in terms of rotation which, for example, is riveted or welded into an opening of the fitting upper part14. A release element32is rotatably mounted by means of this bearing bush30, parallel to the axis A and to the bearing pin22. On the release element32is located fixedly in terms of rotation or configured in one piece with the release element32, a catch element34, whilst a clamping element36—arranged axially adjacent to the catch element34—is mounted pivotably on the bearing bush30. Thus the release element32is mounted inside the bearing bush30and the clamping element36externally on the bearing bush30. The catch element34and the clamping element36are aligned with the latch24when the fitting upper part14is locked. The mode of operation of the catch element34and the clamping element36is disclosed in DE 44 39 644 A1 (corresponding to U.S. Pat. No. 4,223,947), the disclosure thereof being expressly included. The clamping element36bears with a clamping surface curved eccentrically relative to the release element32at an angle outside the self-locking region on a bearing surface of the latch24. The clamping element36is acted upon by a tension spring38formed as a helical spring, so that the clamping element36bears with pretensioning against the latch24. As a result, the fitting upper part14is locked without clearance to the detent plate16. The catch element34is acted upon by an arresting spring40configured as a helical-tension spring. The catch element34and the clamping element36are coupled to one another to be carried along with free travel by means of a slotted pin guide44. To this end, the clamping element36has a slot curved about the release element32, into which a pin of the catch element34engages. The cover20covers the latch24, the catch element34, the clamping element36and the springs38and40and protects said elements from soiling.

In the positions of use normally, i.e. in normal use of the seat, the latch24is held (secured) by the clamping element36in its position and the catch element34is arranged at a short distance (relative to the dimensions of the latch24) from the latch24, preferably bearing against a stop of the fitting upper part14. In the event of a crash, if crash forces act on the latch24, which for example exert a high torque on the fitting upper part14, the clamping element36may open due to the absence of self-locking. After a very slight pivoting motion of the latch24, said latch bears against the catch element34. The catch element34supports, therefore, the latch24, which bears within the self-locking region on the catch element34, preferably tangentially or concentrically and as flat as possible. Thus, the latch24is prevented from opening. Thus, the above-disclosed locking device (consisting of the latch24, the detent plate16as a counter element and the catch element34and the clamping element36as securing elements) locks the fitting upper part14(and thus the freely-pivoting unit12) both normally and in the event of a crash.

On the side of the fitting upper part14remote from the cover20, an unlocking lever46is connected fixedly in terms of rotation to the release element32, to which a first control cable48, in operative connection with the freely-pivoting operating element8, is fastened. Alternatively, the release element32may also be actuated via an electrical actuator, for example a servomotor or the like. For unlocking the fitting upper part14by means of the freely-pivoting operating element8, by means of the first control cable48(and the unlocking lever46) the release element32is rotated about its own axis. The release element32drives the catch element34connected fixedly in terms of rotation therewith, which drives and thus opens the clamping element36, by means of the slotted pin guide44—after passing the free travel—i.e. the clamping element36is separated from the latch24and moved away. The latch24is, as a result, released and may open automatically due to the absence of self-locking. In a modified embodiment, the catch element34may bear against an unlocking finger of the latch24and pull said latch with the further pivoting motion.

In the present embodiment, the two fittings5are configured slightly differently on the two vehicle seat sides. The freely-pivoting unit12of the fitting5of the one vehicle seat side is also described further hereinafter.

In said fitting5, on the fitting upper part14, in particular on the collar thereof (or other projection) (or possibly on the detent plate16) a switching ring50is rotatably mounted concentrically to the axis A. The switching ring50is arranged in the axial direction between the detent plate16and the fitting upper part14(i.e. within the above-mentioned constructional space). The switching ring50has a switching contour52, in the present case a radially projecting step, which is arranged in the lower region of the fitting upper part14. The switching ring50further comprises a radially projecting switching finger54and a spring mounting56, also radially projecting, which are both arranged in the upper region of the fitting upper part14. The other end of the arresting spring40is suspended on the spring mounting56. The switching finger54is located in the pivoting region of the catch element34which preferably has a radially projecting actuating arm34afor cooperating with the switching finger54. On the fitting upper part14, a securing latch64is pivotably mounted by means of a securing pin62. The securing latch64is prestressed by means of a securing spring66against the switching ring50and bears with its free end within the recess16aon the switching ring50or on the stop17. The last-mentioned possibility for bearing is available depending on the inclination of the backrest2set by the adjustment fitting11and possibly the wobble motion between the fitting parts of the adjustment fitting11.

On the fitting lower part9provided on this vehicle seat side, an operating lever73is pivotably mounted in the vicinity of the stop17by means of a switching pin71parallel to the axis A. A locking washer75secures the operating lever73on the switching pin71. A switching spring77configured as a helical-tension spring is, on the one hand, suspended on the operating lever73and, on the other hand, fastened to the fitting lower part9, for example suspended on a spring bolt79, which projects from the fitting lower part9parallel to the switching pin71. The switching spring77pretensions the operating lever73against the stop17, the free end of the operating lever73being arranged in the immediate vicinity of the switching ring50.

The vehicle seat1is able to be longitudinally adjusted by means of a longitudinal adjuster81, i.e. in the longitudinal seat position. To this end, the longitudinal adjuster81comprising two seat rail pairs may be unlocked by means of a handle83and automatically locked after releasing the handle83. The longitudinal adjuster81is, however, also unlocked when freely pivoting the backrest2, so that the vehicle seat1(by means of the longitudinal adjuster81) may be moved to the front, in order to facilitate access to the rear, in addition to the free pivoting of the backrest2. The unlocking of the longitudinal adjuster81takes place, therefore, directly by means of the freely-pivoting operating element8or indirectly, as on the vehicle seat side without a switching ring50an unlocking ring84is provided in the fitting5, instead of said switching ring, which is driven in a manner known per se when pivoting forward the backrest2and thus by means of a Bowden cable or the like controls the locking of the longitudinal adjuster81.

A memory device of the longitudinal adjuster81, by means of which the longitudinal seat position (memory position) set before the free pivoting may be located, is operatively connected by means of a second control cable89, preferably a Bowden cable, with the fitting5which has the switching ring50. The second control cable89is fastened to an arm of the operating lever73, i.e. the memory device of the longitudinal adjuster81controls the operating lever73, in order to be able to release the securing latch64.

The free pivoting of the backrest2which is caused by means of the freely-pivoting operating element8, starts with the unlocking of the fitting upper part14on both vehicle seat sides. The latch24is lifted in the manner described above radially from the second detent stop28of the detent plate16. With the pivoting motion of the backrest2to the front, the securing latch64slides with its free end along the switching ring50and thus reaches the stop17. An oblique contour on the securing latch64ensures that the securing latch64which is brought to bear against the stop17slightly pivots up with the further pivoting motion of the backrest2and slides along the underside of the stop17.

After passing the stop17, the stop contour is set back radially for the securing latch64. By means of its pretensioning the securing latch64now falls behind the stop17(radially inside) and engages behind said stop with a securing latch contour64, and namely outside the self-locking region. Thus it displaces the operating lever73which again engages behind the securing latch64and preferably positively secures said securing latch with a corresponding operating lever contour73a. The pivoting motion of the backrest2is completed and secures the fitting upper part14(and thus the backrest2). The pivoted-forward backrest2is now located in the freely-pivoted position which permits unhindered access to the rear. At the same time, the vehicle seat1is in a forward longitudinal seat position.

In order to return to the previously adopted position of use, firstly the vehicle seat1is again moved to the rear, for example by pulling on the backrest2. When the memory position is reached, the longitudinal adjuster81is locked and thus pulls on the second control cable89. The second control cable89now pivots the operating lever73, which releases the securing latch64. The backrest2opens the securing latch64by the commencement of its rearward pivoting motion and may then be pivoted back unhindered. The latch24thus reaches the second detent stop28again and when reaching the previously adopted position of use again falls behind the second detent stop28(radially inside) so that the fitting upper part14and thus the fitting5is again locked. The operating lever73, which is not further acted upon by the second control cable89, is pulled back by the associated switching spring77again into its initial position.

If the memory position is not reached, for example due to objects in the footwell—instead of the previously described automatic opening—the securing of the backrest2may be manually opened by means of the freely-pivoting operating element8. As a result, by means of the first control cable48the release element32is rotated, which pivots the catch element34. The catch element34presses by means of its actuating arm34aonto the switching finger54of the switching ring50. Due to an oblique portion provided there the switching ring50is rotated, whereby the switching contour52comes to bear against the operating lever73, and opens said operating lever. The operating lever73, as a result, releases the securing latch64. As described above, the backrest2may now be pivoted back.

The securing of the fitting upper part14by means of the securing latch64in the freely-pivoted position of the backrest2is, in the present case, designed so that the wobble loop of the adjustment fitting11has no influence. As is visible fromFIGS. 11 and 12, due to the wobble loop the securing pin62adopts different positions relative to the stop17. However, this only has an effect on the support of the securing latch64on the stop17and on the support of the locking lever73on the securing latch64at an angle which is compensated by a suitable shape of the securing latch contour64aand the locking lever contour73a. Ultimately, the same degree of closing m is always produced, i.e. the spacing between the two bearing points (securing latch—stop, locking lever—securing latch) is constant.

While a specific embodiment of the invention has been described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.