Locking device for a vehicle seat

[0002] The present invention relates to a locking device for a vehicle seat.

[0003] It is known for a locking device to be part of an articulated fitting for a motor vehicle seat. An inclination adjustment provided by such a fitting takes place between a lower part of the fitting, which is fixed to the seat part, and an upper part of the fitting, which is fixed to the backrest. The lower part of the fitting and the upper part of the fitting are locked, except when the backrest is being pivoted, by means of a latch mounted on the lower part of the fitting. The latch is secured by a prestressed, eccentric clamping element. An intercepting element having a concentric intercepting surface serves to support the latch in the event of a crash. Due to manufacturing tolerances, especially in the case of finely stepped inclination adjustment, the distance between the latch and the intercepting element may result in it no longer being possible to absorb the crash load.

[0004] One aspect of the present invention is the provision of an improved locking device of the above-described type. In accordance with this aspect, the locking device is for releasably restricting relative movement between first and second parts of a vehicle seat, or the like, that are mounted for moving relative to one another, and the locking device includes first and second toothed elements mounted for alternately being engaged to one another and disengaged from one another. The first toothed element is for being connected to the first part of the vehicle seat, the second toothed element is for being connected to the second part of the vehicle seat, and the locking device is for allowing the relative movement between the first and second parts of the vehicle seat while the first and second toothed elements are disengaged from one another. The locking device further includes a clamping element that generally keeps the first and second toothed elements engaged to one another while the locking device is in a locked state. The first and second toothed elements restrict relative movement between the first and second parts of the vehicle seat while the first and second toothed elements are kept engaged to one another. The locking device additionally has an intercepting element including at least two intercepting surfaces. In the event of a crash, the intercepting element supports the first toothed element via at least one of the intercepting surfaces to keep the first and second toothed elements engaged to one another.

[0005] In accordance with one nonlimiting example of the present invention, the intercepting element is for supporting the first toothed element via a first intercepting surface of the two intercepting surfaces, rather than via a second intercepting surface of the two intercepting surfaces, to keep the first and second toothed elements engaged to one another when the locking device has first tolerances and the crash occurs. Similarly and in accordance with another nonlimiting example of the present invention, the intercepting element is for supporting the first toothed element via the second intercepting surface, rather than via the first intercepting surface, to keep the first and second toothed elements engaged to one another when the locking device has second tolerances, which are different from the first tolerances, and the crash occurs.

[0006] On account of the intercepting element having at least two different intercepting surfaces, the functioning of the intercepting element can be ensured and the loss of contact of the toothing minimized even at relatively large tolerances. Two or more intercepting surfaces can be provided. The intercepting surfaces, which are formed preferably concentrically or at least approximately concentrically with the pivot axis of the intercepting element, are preferably arranged adjacent to each other on the intercepting element, i.e. are connected to each other, preferably have small central angles, i.e. an angle of a few degrees, and preferably form a convex contour on the intercepting element. Each of these measures increases the probability of one of the intercepting surfaces taking up the smallest possible distance from the first toothed element, i.e. being aligned parallel to a bearing surface of said toothed element. This preferably applies to just one intercepting surface.

[0007] In a preferred embodiment, the two or more intercepting surfaces are at a different distance from the pivot axis of the intercepting element. Radial tolerances can also be compensated for by a slightly eccentric shape of the intercepting element. In this case, steps can be provided between the intercepting surfaces, which steps somewhat reinforce the eccentric shape of the intercepting element.

[0008] A vehicle seat according to the invention, in particular a motor vehicle seat, has at least one vehicle seat adjuster or a seat-fixing means on the vehicle floor having a locking device according to the invention. A vehicle seat adjuster of this type may, for example, be a latching fitting having combined inclination adjustment and a free-pivoting function, where the locking device is released in both cases, or may be any desired articulated fitting, for example a tumbling fitting where the locking device is released only for the free-pivoting process. The vehicle seat adjuster may optionally also be a longitudinal adjuster, height adjuster or inclination adjuster. The locking device according to the invention may also be used for the seat-fixing means by which the vehicle seat is fixed to the vehicle floor. The toothed elements which are used can be pivotable latches or latches mounted in a floating manner and having a lateral toothing, displaceable locking bars having a toothing at the front end, gearwheels having an external toothing, hollow wheels having an internal toothing or suitable combinations thereof.

[0009] Having thus described the invention in general terms, the invention is explained in greater detail in the following with reference to two exemplary embodiments that are illustrated in the drawings, which are not necessarily drawn to scale, and wherein:

[0010] FIG. 1 shows a lateral view, only illustrated in part, of the first exemplary embodiment in a locked state,

[0011] FIG. 2 shows a schematic side view of a vehicle seat having the first exemplary embodiment,

[0012] FIG. 3 shows a detail from an illustration corresponding to FIG. 1 of the first exemplary embodiment, in a position after a crash,

[0013] FIG. 4 shows an illustration corresponding to FIG. 3 of the first exemplary embodiment in an open position, and

[0014] FIG. 5 shows a section through the second exemplary embodiment.

[0015] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

[0016] The first exemplary embodiment relates to a locking device for an articulated fitting 3 of a vehicle seat 4 which is used in a motor vehicle. The arrangement of the vehicle seat 4 in the motor vehicle and the normal travelling direction thereof define the following directional details. The articulated fitting 3 is designed as a latching fitting, but may also be designed as a tumbling fitting. The articulated fitting 3 comprises a lower part 5 of the fitting, which is connected to a seat part 6 of the vehicle seat 4, and an upper part 7 of the fitting, which is connected to a backrest 8 of the vehicle seat 4. During a free-pivoting process, the two fitting parts 5 and 7 can be pivoted relative to each other about a backrest rotational axis 9 and, in the exemplary embodiment, also during an inclination adjustment of the backrest 8, and are otherwise locked to each other by the locking device.

[0017] For the locking procedure, on the one side a pivotable latch 11 is coupled as a first toothed element to the lower part 5 of the fitting by means of a first bolt 13, and, on the other side, the upper part 7 of the fitting has, concentrically with the backrest rotational axis 9, a toothed ring 15 which is fixed to the upper part of the fitting as a second toothed element. In the locked state of the locking device, the latch 11 engages with a toothing, which is provided at the free end of the latch 11, into the toothing of the toothed ring 15 without self-locking. In order to be able to adjust the articulated fitting 3 which is used as a backrest inclination adjuster, or in order to be able to freely pivot the backrest 8 in order to gain access to the rear seat bench, the latch 11 can be pivoted away from the toothed ring 15. The latch 11 is assigned a control element 17 which is rotationally fixed or connected integrally to it.

[0018] In order to keep the latch 11 in engagement with the toothed ring 15, a clamping element 21 is provided which is coupled to the lower part 5 of the fitting by means of a second bolt 23. The pivotable clamping element 21 is spring-loaded in the direction of the latch 11 where a clamping surface 27 of the latch 11 is arranged in the pivoting region of the free end of the clamping element 21, which clamping surface is formed on that side of the control element 17 which faces away from the toothed ring 15, but could alternatively be situated on the latch 11. In the locked state, the clamping element 21, which is provided with an eccentric contour on the free end, bears against the clamping surface 27 with tension and outside the self-locking range, so that the latch 11 is held in the toothed ring 15.

[0019] An intercepting element 30, which is mounted pivotably about the second bolt 23, is formed separately from the clamping element 21, but may be carried along by the latter. The intercepting element 30 has, next to one another on its free end, a first intercepting surface 31 whose distance from the second bolt 23 is R1, a second intercepting surface 32 whose distance from the second bolt 23 is R2, a third intercepting surface 33 whose distance from the second bolt 23 is R3, a fourth intercepting surface 34 whose distance from the second bolt 23 is R4, and a fifth surface 35. The fifth surface 35 restricts the stroke of the latch in the opened state. Small steps are formed between the associated intercepting surfaces 31, 32, 33 and 34 by the different distances R1, R2, R3 and R4. The four intercepting surfaces 31, 32, 33 and 34, which are arranged tangentially with regard to the second bolt 23, are curved concentrically with each other about the second bolt 23. The four intercepting surfaces 31, 32, 33 and 34 are each at an angle of approximately 6° to 9°, preferably 8°, to each other. The intercepting element 30, which is spring-loaded with respect to the clamping element 21, is coupled to the clamping element 21 by means of carryalong stops or slot and pin guides, so that when the locking device is unlocked the intercepting element 30 can carry along the clamping element 21.

[0020] In the normal, locked state one of the four intercepting surfaces 31, 32, 33 and 34 lies at a small distance opposite a bearing surface 36 of the latch 11. Tolerances due to the manufacturing procedure ultimately decide which of the four intercepting surfaces 31, 32, 33 and 34 lies in the direct vicinity of the bearing surface 36 and is approximately parallel to the latter. In the event of a crash, the backrest 8 exerts a torque on the upper part 7 of the fitting, which exerts, via the toothed ring 15, an opening torque on the latch 11 which, in turn, presses back the clamping element 21 counter to its spring loading. The bearing surface 36 then comes to bear against one of the intercepting surfaces 31, 32, 33 or 34. On account of the at least approximate concentricity of the intercepting surfaces 31, 32, 33 and 34, the latch 11 is unable to exert an opening torque on the intercepting element 30, so that the latch 11 and the intercepting element 30 remain in this position, i.e. the intercepting element 30 supports the latch 11. At the same time, the latch 11 is still in engagement with the toothed ring 15, and so the locking device remains locked.

[0021] In the second exemplary embodiment, a locking device 101 according to the invention for an articulated fitting designed as a latching fitting is provided, in order to be able to infinitely lock said articulated fitting. Components which are identical to components of the first exemplary embodiment or have the same function as the latter bear reference numbers which are correspondingly higher by 100. Otherwise, the second exemplary embodiment and the first exemplary embodiment correspond. Mounted in a floating manner on the lower part of the fitting, which is situated above the plane of the drawing in FIG. 5, is, as a first toothed element, a toothed locking bar 111 which interacts with a toothed ring 115 which is provided on the upper part of the fitting as the second toothed element.

[0022] A cam 117, which projects into the plane of the drawing in FIG. 5, is formed on the locking bar 111 by means of material being forced out. A first clamping element 121, which is coupled pivotably to the lower part of the fitting by means of a first bolt 123, bears in a spring-loaded manner with an eccentric contour against the cam 117 on the side which faces away from the toothing of the locking bar 111, in order to keep the locking bar 111 in engagement with the toothed ring 115. A first intercepting element 126 is likewise mounted pivotably on the first bolt 123, is coupled by means of a carry-along pin and a stop to the first clamping element 121 and is spring-loaded with respect to the latter. In the normal, locked state of the locking device 101 the free end of the first intercepting element 126, which may also be stepped, is arranged at a small distance from that end of the locking bar 111 which faces away from the toothing of the locking bar 111.

[0023] The locking bar 111 acts on the circular toothed ring 115 in the radial direction. In order to be able to engage at inclination angles which deviate by less than one tooth width from the tooth pitch of the toothed ring 115, the locking bar 111 is mounted in a floating manner in that the holder, which is produced by the forcing out of the cam 117, surrounds an island 105 which is forced out of the lower part of the fitting and has a smaller cross section. The locking bar 111 can therefore be guided and supported laterally in the region of its lateral flanks 136, i.e. in the tangential direction with regard to the toothed ring 115. For this purpose, a second clamping element 138 and a second intercepting element 139 are mounted on a second bolt 137 on the one flank 136, while a third clamping 142 and a third intercepting element 143 are mounted on a third bolt 141 on the other flank 136.

[0024] The second and third clamping elements 138 and 142, respectively, correspond in their function and manner of action to the first clamping element 121, i.e. are likewise spring-loaded and by means of an eccentric contour interact with the cam 117. The second and third intercepting elements 139 and 143, respectively, are each coupled correspondingly to the associated clamping element 138 and 142 by means of slot and pin guides. At the free end, the second and third intercepting elements 139 and 143 have a plurality of intercepting surfaces 139′ and 143′, respectively, which are formed concentrically with the bolt 141 and have stepped radii. Depending on the position of the locking bar 111 one of the intercepting surfaces 139′ or 143′ is situated in each case in the direct vicinity of the associated flank 136 of the locking bar 111, so that, corresponding to the situation in the first exemplary embodiment, in the event of a crash they come to bear against each other without an opening torque being transmitted.

[0025] Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for