Fitting for a vehicle seat

In the case of a fitting (10) for a vehicle seat, in particular for a motor vehicle seat, having a first fitting part (11), a second fitting part (12) in geared connection with the first fitting part (11), and a rotatably mounted eccentric (26, 27) driven by a driver (21, 26) to cause relative rolling between the first fitting part (11) and the second fitting part (12), a third fitting part (54) can be both pivoted freely relative to the first fitting part (11) in an unlocked state and locked with respect to the first fitting part (11) in a locked state, wherein a disengagement mechanism (80) is provided for maintaining the unlocked state of the third fitting (11) part during pivoting freely.

BACKGROUND OF THE INVENTION

The present invention relates to a fitting for a vehicle seat, in particular for a motor vehicle seat, comprising a first fitting part and a second fitting part, wherein there is geared connection between the first fitting part and the second fitting part so that there can be relative rolling between the first fitting part and the second fitting part; a rotatably mounted eccentric for being driven, and for causing the relative rolling between the first fitting part and the second fitting part in response to the eccentric being driven; a driver for driving the eccentric so that the eccentric causes the relative rolling between the first fitting part and the second fitting part, wherein the fitting is operative for steplessly adjusting inclination of a backrest of the vehicle seat by way of the relative rolling between the first fitting part and the second fitting part, which occurs in response to the eccentric being driven; a third fitting part mounted for being pivoted relative to the first fitting part, enabling pivoting of the backrest of the vehicle seat relative to both the first fitting part and the second fitting part; a locking mechanism for providing locked and unlocked states of the third fitting part, wherein the third fitting part is at least indirectly locked with respect to the first fitting part during the locked state of the third fitting part, and the third fitting part can be pivoted relative to the first fitting part during the unlocked state of the third fitting part.

A fitting that is of this type is disclosed in U.S. patent application Ser. No. 11/654,825. The first fitting part is provided with a detent element interacting with the third fitting part and also serving as a stopper for the relative movement of the first fitting part and the second fitting part. If the third fitting part, i.e. the backrest, is pivoted forward and reaches its frontmost position, the locking mechanism will provisionally lock the third fitting due to the special shape of the detent element.

BRIEF SUMMARY OF SOME ASPECTS OF THE INVENTION

An aspect of the present invention is the provision of improvements to a fitting of the type described immediately above, for example to increase the range of applications for such a fitting.

In accordance with one aspect of the present invention, a fitting for a vehicle seat, in particular for a motor vehicle seat, comprises a first fitting part and a second fitting part, wherein there is geared connection between the first fitting part and the second fitting part so that there can be relative rolling between the first fitting part and the second fitting part; a rotatably mounted eccentric for being driven, and for causing the relative rolling between the first fitting part and the second fitting part in response to the eccentric being driven; a driver for driving the eccentric so that the eccentric causes the relative rolling between the first fitting part and the second fitting part, wherein the fitting is operative for steplessly adjusting inclination of a backrest of the vehicle seat by way of the relative rolling between the first fitting part and the second fitting part, which occurs in response to the eccentric being driven; a third fitting part mounted for being pivoted relative to the first fitting part, enabling pivoting of the backrest of the vehicle seat relative to both the first fitting part and the second fitting part forward into a dump (e.g., substantially horizontal) position; a locking mechanism for providing locked and unlocked states of the third fitting part, wherein the third fitting part is at least indirectly locked with respect to the first fitting part during the locked state of the third fitting part, and the third fitting part can be pivoted relative to the first fitting part during the unlocked state of the third fitting part; and a disengagement mechanism for maintaining the unlocked state of the third fitting part during pivoting into the dump position.

The use of an eccentric planetary gear permits the angle of inclination of the backrest to be steplessly adjusted. The eccentric planetary gear can be driven manually or by way of a motor.

Using a third fitting part, which is pivotable relative to the first fitting part and can be locked with the first fitting part, it is possible to pivot the backrest freely and/or into a dump (e.g., substantially horizontal) position, independently of the inclination setting, and without influencing that setting. The number of possible areas of application and the comfort level are increased.

The disengagement mechanism avoids a locking of the third fitting part in the dump position.

Other aspects and advantages of the present invention will become apparent from the following.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT

A vehicle seat1for a motor vehicle includes a seat part3and a backrest4. The inclination of the backrest4can be adjusted relative to the seat part3by way of a motor drive. For adjusting the inclination of the backrest, a handwheel5(or an electric motor) is used to rotate a drive shaft7which is arranged horizontally in the transition zone between the seat part3and the backrest4. On both sides of the vehicle seat1, the drive shaft7engages in a fitting10in a rotationally fixed manner that will be described further below. The drive shaft7defines the directional data of a cylindrical coordinate system that is used in this description.

The fitting10is designed as a geared fitting in which a first fitting part11and a second fitting part12are connected with each other by way of a gear for the purpose of making and securing adjustments. More specifically, the first fitting part11and the second fitting part12are connected by way of an eccentric planetary gear—in the exemplary embodiment a self-locking planetary gear—as described, for example, in U.S. Pat. No. 5,634,689. The entire disclosure of U.S. Pat. No. 5,634,689 is incorporated herein by reference. In the exemplary embodiment, the plate-shaped second fitting part12is firmly connected with the structure of the seat part3, i.e. it is fixedly attached to the seat part3, by means of a seat part adapter12a. In another arrangement the positions of the fittings11and12can be interchanged. The two fitting parts11and12may also be disc-shaped.

In order to form the gear mechanism, a toothed wheel16with external toothing is embossed on the second fitting12, a toothed ring17with internal toothing is formed on the first fitting11, and the toothed wheel and the toothed ring intermesh with each other. The diameter of the tip circle of the external toothing of the toothed wheel16is smaller by at least the height of one tooth than the diameter of the root circle of the internal toothing of the toothed ring17. A corresponding difference of at least one tooth between the number of teeth in the toothed wheel16and in the toothed ring17permits the toothed ring17to roll on the toothed wheel16. Thus, an eccentric planetary gear is provided.

Concentrically to the internal toothing of the toothed ring17, the first fitting part11has an integrally formed collar element19on the side facing the toothed wheel16. A driver21is mounted by way of a hub22inside the collar element19. The driver21is provided with a receptacle (e.g., provided centrally with a borehole23) for receiving the drive shaft7. The profile of the borehole23matches the profile of the drive shaft7, which in the exemplary embodiment is the profile of a splined shaft. In a radial distance to its hub22, the driver21includes a driving segment24arranged on the (radial) outside of the collar element19and extending around the collar element19for less than 160° in the circumferential direction. At one end of the hub22, the driver21is provided with a cover disc25having a larger diameter than the hub22. In the present embodiment, the driver21with hub22, driving segment24, and cover disc25is made of one piece, but it may also be made of several pieces, as described, for example, in U.S. Pat. No. 7,188,903. The entire disclosure of U.S. Pat. No. 7,188,903 is incorporated herein by reference.

On its (radial) outside, the collar element19supports two wedge segments27which, by way of their curved outer surfaces, support a sliding bearing bushing28which is pressed in a rotationally fixed manner into the second fitting part12. The two wedge segments27together extend for more than 180° in the circumferential direction. The driving segment24engages with play between the narrow ends of the wedge segments27. The driver21may be provided with axial projections touching the two wedge segments27, to secure the wedge segments27in the axial direction.

The broad ends of the wedge segments27face each other. Each of the broad ends of the wedge segments27accommodate, by way of a recess defined by projecting sections of material, an angled end finger of an annular spring35. The spring35pushes (e.g., urges) the wedge segments27apart from one another in the circumferential direction, so that in the event of the wedge segments27becoming blocked during operation or if the backrest4comes up against a load, the radially outer, projecting sections of material (which are located at the broad ends of the wedge segments27) may come into contact with and act upon one another.

The driver21is secured axially on the outside of the first fitting part11by way of a clipped-on securing ring43. A sealing ring44is provided on the outside of the second fitting part12, between the embossing for the toothed wheel16and the cover disc25of the driver21.

The wedge segments27define an eccentric which, by extension in the direction of the eccentricity, presses the toothed wheel16into the toothed ring17at an engagement point defined by the cooperative design/interaction between the toothed wheel, toothed ring and eccentric. When the drive force is provided by the rotating drive shaft7, torque is transmitted first to the driver21and by the rotating driver21to the eccentric, so that the eccentric slides along the sliding bearing bushing28, changing the direction of the eccentricity and thus changing the point of engagement of the toothed wheel16in the toothed ring17, which manifests itself as a wobbling rolling movement, i.e. as relative rotation with a superimposed wobbling motion. The inclination of the backrest4can thus be steplessly adjusted between several use positions.

In order to limit the range of adjustment between the first and second fitting parts11,12, the first fitting part11is provided with a first stopper47. If the backrest4is inclined to the front-most position, the first stopper47will come to bear against an adapter projecting axially from the second fitting part12or another part of the structure of the seat part3.

During an unlocked state discussed in greater detail below, the backrest4can be freely pivoted, by way of the fitting10, e.g., in order to facilitate access to a row of seats behind the vehicle seat1. The pivoting of the backrest4can even be continued to achieve a more or less (e.g., substantially) horizontal position of the backrest, which is referred to as the dump position, e.g., in order to enlarge the space for storing goods. According to the invention, the backrest4can be separately unlocked and manually pivoted forward, without moving the two fitting parts11and12relative to each other. In accordance with the exemplary embodiment, when the backrest4has been pivoted forwardly to the “dump position”, the backrest4extends more or less (e.g., substantially) horizontally and is typically in opposing face-to-face relation with seat part3. In accordance with the exemplary embodiment and more specifically, the backrest4may be (e.g., typically is) in opposing face-to-face contact with the seat part3while the backrest4is in the dump position, as discussed below.

The fitting10comprises an annular-shaped bearing ring51that has a radially projecting flange at one end face. At its other end face, the bearing ring51is fixedly connected to the first fitting11, preferably by laser welding. The fitting10further comprises a third fitting part54which is connected to the structure of the backrest4, i.e. is fixedly attached to the structure of the backrest4, by means of a backrest adapter54a. The plate-shaped third fitting part54is pivotably supported on the bearing ring51, so that the third fitting part is pivotable around the central axis defined by the drive shaft7in order to permit centered, free pivoting relative to the first fitting part11; otherwise, however, the third fitting part54is locked (e.g., indirectly locked) with the first fitting part11.

A detent element55is integrally formed with the first fitting part11. The detent element55is spaced apart from the first stopper47. The detent element55serves to lock the third fitting element54to the first fitting part11. For this purpose, a pawl60is pivotably mounted on the third fitting part54by way of a first bearing bolt62. The pawl60is pivotable in the same plane as the detent element55, and the first bearing bolt62extends parallel to the drive shaft7. On the side facing the detent element55, the pawl60is provided with teeth for interacting with the detent element55, which is also formed as teeth. A stop bolt64of the third fitting part54bears against a second stopper65of the first fitting part11in the rearwards-pivoting direction of the third fitting element54.

In accordance with the exemplary embodiment of the present invention, the detent element55and the pawl60can each be characterized as being part of a locking mechanism that is for: locking the third fitting part54by engagement, to provide a locked state of the third fitting part54; and unlocking the third fitting part54by disengagement, to provide an unlocked state of the third fitting part54.

Parallel to the first bearing bolt62, a second bearing bolt67is arranged on the third fitting part54. By way of the second bearing bolt67, a securing element71is pivotably mounted on the third fitting part54. The securing element71is pivotable in the same plane as the pawl60and is acted upon by a securing spring73. The securing element71secures the locked state of the third fitting part54by acting on the pawl60to hold it engaged in the detent element55. An unlocking pin75projects axially from the securing element71and passes outwards through a slot76in the third fitting part54. Otherwise, the pawl60and the securing element71are protected by a cover78on the third fitting part54.

In order to unlock the third fitting part54—for example, by way of a manually operated hand lever79for pulling a cable that is connected to the unlocking pin75—the unlocking pin75is pivoted in the slot76, thereby taking with it the securing element71and pivoting the securing element relative to/away from the pawl60. Then, the securing element71no longer acts upon the pawl60. The pivoting securing element71comes to bear against an unlocking finger (e.g., a substantially radially projecting unlocking finger) on the pawl60, thereby pulling the pawl60open. The pawl60is thus completely disengaged. The backrest4can now be pivoted forward into the dump position.

The peripheral section of the first fitting part11between the detent element55and the stopper47projects farther outwardly in the radial direction than the section ahead the stopper47or than the base of the teeth of the detent element55. Thus, as long as the pawl60is located in the section between the detent element55and the stopper47, the pawl60will not engage, even if the unlocking pin75is no longer pulled (with the lack of pulling on the unlocking pin75causing the spring73to move the securing element71towards and into contact with the pawl60so that the pawl is urged inwardly). If the pawl60passes the stopper47(after about 73°) and reaches the section ahead the stopper47, and if the unlocking pin75is no longer pulled, a fitting according to the state of the art will allow the pawl60to engage with the section ahead the stopper47in a manner such that the unlocked state would not be maintained in the dump position.

According to the invention, a disengagement mechanism80is provided for maintaining the unlocked state of the third fitting part54in the dump position. The disengagement mechanism80comprises a cam ring81with a radially projecting cam83attached to the cam ring81. The cam ring81is fixed to the first fitting part11. The disengagement mechanism80also comprises a lever84pivotably mounted on the third fitting part54by means of a third bearing bolt86, with a return spring88acting upon the lever84. The lever84has a section next to the cam83and a section next to the unlocking pin75(and a section next the third bearing bolt86). In the use positions of the vehicle seat1(e.g., when the backrest4is positioned so that a user may sit in the vehicle seat), the lever84neither interacts with the cam83nor with the unlocking pin75. If the backrest4(and thus the third fitting part54) is pivoted forward, the lever84comes into contact with the cam83and is pivoted by the cam83thus pushing against the unlocking pin75. As a result, even if the unlocking pin75is no longer pulled, and even if the third fitting part54reaches the section of the first fitting part11ahead the stopper47, the securing element71will be kept open by the disengaging mechanism80, and thus the pawl60will be kept disengaged.

When the backrest4is being pivoted backwards and thereby out of the dump position, the lever84leaves the cam83, the return spring88moves the lever84away from the unlocking pin75, the stop bolt64comes to bear against the second stopper65of the first fitting part11, the pawl60again enters into its locking state, and the securing element71secures this locked state.

It will be understood by those skilled in the art that while the present invention has been discussed above with reference to an exemplary embodiment, various additions, modifications and changes can be made thereto without departing from the spirit and scope of the invention as set forth in the following claims.