Swiveling device for vehicle seats

Abstract

The invention relates to a swiveling device (1) for vehicle seats including a stator (3a, 3b, 11), intended to be fastened to the vehicle floor, a rotor (5), rotatable relative to the stator and intended to be fastened to the vehicle seat frame, and a locking mechanism (21, 23, 25) for selectively allowing or preventing rotation of the rotor relative to the stator. The rotor can be locked relative to the stator in a plurality of discrete locking positions. In order to obtain a smooth and comfortable operation, the swiveling device is provided with resistance means (31, 31a, 31b) arranged in the proximity of said locking positions, so that resistance to the rotation of the rotor relative to the stator is remarkably increased and the user receives the information that a selectable position of the vehicle seat relative to the vehicle floor is being reached.

Description

Swiveling device for vehicle seats

[0001] The present invention relates to a swiveling device for a vehicle seat.

[0002] More particularly, the present invention relates to a manually operated swiveling device for a vehicle seat.

[0003] Vehicle seats provided with a swiveling device are known and widespread.

[0004] A swiveling device allows the vehicle seat to rotate about an axis that is substantially perpendicular to the vehicle floor.

[0005] In general, a swiveling device allows a rotation of the corresponding vehicle seat over an angle of at least 90°, thus allowing the vehicle seat to pass from a first position, in which the seat is oriented towards the traveling direction of the vehicle, to a second position, in which the seat is oriented towards the adjacent vehicle door.

[0006] In this way, the swiveling device facilitates the entry of the driver or passenger into the cockpit and / or the exit therefrom.

[0007] It will be evident that swiveling devices are particularly useful for individuals with limited mobility, especially with restricted lower body strength and movement capability.

[0008] Accordingly, they can be introduced into the vehicle cockpit as an aftermarket adaptation to an existing passenger vehicle, replacing the original seat anchoring arrangement to the vehicle floor.

[0009] In general, swiveling devices are inserted between the original vehicle seat and the vehicle floor in place of the original seat anchoring arrangement, and they comprise a stator, which is coupled to the vehicle floor, and a rotor, which is coupled to the seat cushion frame and can rotate relative to the stator.

[0010] In order to selectively allow or prevent rotation of the rotor relative to the stator, a locking pin is usually provided, and an actuating lever is used for switching the locking pin from a locking position (in which rotation of the rotor relative to the stator is prevented) to an unlocking position (in which rotation of the rotor relative to the stator is allowed).

[0011] Once the locking pin has been switched to the unlocking position, rotation of the rotor relative to the stator can be obtained.

[0012] In detail, the swiveling device may include a motor for mechanically or electromechanically driving rotation of the rotor relative to the stator.

[0013] In case of motorized swiveling devices, the swiveling device may also include a control unit for controlling operation of the motor, so that a rotation of a predetermined, desired angle of the vehicle seat relative to the vehicle floor is obtained.

[0014] Once such rotation of said predetermined, desired angle has been carried out, the locking pin is brought back to the locking position, and the rotor of the swiveling device is blocked in the new desired position relative to the stator.

[0015] As an alternative, rotation of the swiveling device may be manually driven by the user sitting on the vehicle seat. That is, the user brings the locking pin to the unlocking position, and then they cause the swiveling device to rotate by exerting a force on the seat cushion.

[0016] The structure of manually operated swiveling devices is undoubtedly simpler and cheaper than the structure of motorized swiveling devices.

[0017] However, such manually operated swiveling devices are not free from drawbacks.

[0018] In such swiveling device, a plurality of discrete positions in which the rotor can be blocked relative to the stator are provided. Such discrete blocking positions correspond to positions of the vehicle seat relative to vehicle floor that can be selected by the user.

[0019] For instance, four discrete positions at 90° from one another can be provided.

[0020] By bringing the locking pin to the unlocking position and by making the swiveling device rotate, the user can move the vehicle seat from a first, starting position among such selectable discrete positions to a second, final position among such selectable discrete positions.

[0021] However, it is very hard for the user to apply a force allowing to exactly reach a selectable position.

[0022] It is much more likely that the user obtains either an underrotation of the swiveling device, thus not reaching the desired final position, or an overrotation of the swiveling device, thus going beyond the desired final position.

[0023] This makes the operation of the swiveling device uncomfortable, as the user will be forced to make the swiveling device slightly rotate back and forth until the selectable position is reached.

[0024] US 2024 / 083307 discloses a swiveling device for a vehicle seat including rotating disc and a fixed disc and a locking mechanism for selectively allowing or preventing rotation of the rotating disc relative to the fixed disc. The locking mechanism includes a vertical latch mounted on the rotating disc and at least one locking hole provided on the fixed disc. The vertical latch includes a bracket fastened to the rotating disc and at least two locking pins mounted on the bracket, protruding through corresponding pin holes provided in the rotating disc and vertically movable relative to the bracket.

[0025] Far from the locking hole, the distance between the rotating disc and the fixed disc is greater than the length of the portion of the locking pins protruding from the rotating disc, so that the rotating disc can freely rotate relative to the fixed disc. Climbing slopes are provided on the fixed disc at the two sides of the locking hole, so that the locking hole is located at a highest position of the climbing slopes. When the vertical latch on the rotating disc approaches a locking position, the ends of the two locking pins encounter the climbing slope on the fixed disc, and the climbing slope pushes the locking pins to move upward by overcoming the resistance of spring elements. When the locking pins reach the position of the locking hole, the spring elements urge them downwards and into the locking hole for locking.

[0026] The locking mechanism disclosed in US 2024 / 083307 has several drawbacks.

[0027] First of all, the locking pins move in the vertical direction so that their operation can be affected by external factors such as the user’s weight, which makes the locking mechanism scarcely reliable.

[0028] Secondly, both the unlocking mechanism and the climbing slope provided on the fixed disc cooperate with the same components, i.e. the locking pins, and counteract the same elements, i.e. the springs urging the locking pins downwards, which makes the operation of the swiveling device scarcely reliable.

[0029] Thirdly, no measure is provided for making the operation of the swiveling device more comfortable.

[0030] The main object of the present invention is to obviate to the above-mentioned drawbacks, by providing a swiveling device that allows the user to comfortably move from a first starting position among a plurality of discrete selectable positions to a second final position among such plurality of discrete selectable positions.

[0031] Another object of the present invention is to provide a swiveling device having a solid construction and an improved passive safety performance in case of front, rear and lateral crashes.

[0032] These and other objects are achieved by a swiveling device as claimed in the appended claims.

[0033] The swiveling device according to the invention includes a stator, intended to be fastened to the vehicle floor (or to a vehicle component integral to the vehicle floor), and a rotor, rotatable relative to the stator and intended to be fastened to the vehicle seat frame (or to a vehicle component integral to the vehicle seat frame).

[0034] The swiveling device further includes a locking mechanism for selectively allowing or preventing rotation of the rotor relative to the stator.

[0035] According to a preferred embodiment of the invention, the locking mechanism includes a locking member and a plurality of discretely arranged seats suitable for receiving said locking member, said seats defining corresponding discrete locking positions of the rotor relative to the stator.

[0036] The seats are preferable uniformly distributed along the circumference of the swiveling device.

[0037] According to another preferred embodiment of the invention, the locking mechanism includes a seat and a plurality of discretely arranged locking members suitable for being received in said seat; in this embodiment, said locking members define the discrete locking positions of the rotor relative to the stator.

[0038] The locking members are preferable uniformly distributed along the circumference of the swiveling device.

[0039] In both embodiments, such discrete locking positions correspond to positions of the vehicle seat relative to the vehicle floor that can be selected by the user.

[0040] The swiveling device further includes an actuating member for switching the locking mechanism from a locking configuration, in which rotation of the rotor relative to the stator is prevented, to an unlocking configuration, in which rotation of the rotor relative to the stator is allowed overcoming the resistance of first resistance means.

[0041] According to the invention, second resistance means, separate and independent form the first resistance means, are provided along the circumference of the swiveling device in the proximity of said discrete locking positions, such second resistance means offering an increased resistance to the rotation of the rotor relative to the stator.

[0042] Due to the provision of said second resistance means, when the user makes the swiveling device rotate, they feel an increased resistance as soon as they are approaching a discrete locking position.

[0043] As a result, the user gets the information that they is reaching a selectable position and can reduce and then stop the force exerted on the vehicle seat for causing the rotation of the swiveling device.

[0044] According to a preferred embodiment of the invention, the second resistance means are obtained by a reduction of the gap in the radial direction between the rotor and the stator.

[0045] More particularly, the second resistance means include first resistance elements arranged on the rotor and second resistance elements arranged on the stator, the first and second resistance elements cooperating with each other for obtaining a reduction of the radial gap between the rotor and the stator.

[0046] For instance, the rotor can be provided with a radially outwardly projecting elastic member, and the stator can be provided with radially inwardly projecting bosses in the proximity of the discrete locking positions.

[0047] The radial extension of the outwardly projecting elastic member can be chosen smaller than the radial distance between the outer surface of the rotor and the inner surface of the stator but greater than the radial distance between the outer surface of the rotor and the surface of the projecting bosses provided on the inner surface of the stator.

[0048] As a result, when the elastic member meets a boss during rotation of the rotor relative to the stator, the elastic member gets compressed against the boss, thus generating friction and increased resistance to rotation.

[0049] It is evident, that it could also be possible to provide the rotor with an outwardly projecting boss, and the stator with inwardly projecting elastic members in the proximity of the discrete seats.

[0050] In addition, multiple elastic members can be used in conjunction with multiple bosses to increase the magnitude of the resistance to rotation, or to set it to the value requested by the customer.

[0051] It is also evident that the second resistance means could be implemented by means of components having a different construction and operation, provided that they are suitable for generating friction and for increasing the resistance to the rotation of the rotor relative to stator.

[0052] Even assuming that in US 2024 / 083307 the climbing slopes provided in the fixed disc offer an increased resistance to the rotation of the rotating disc relative to the fixed disc – which effect is not mentioned in the disclosure of this document – the construction and operation of the swiveling device according to the invention is remarkably different.

[0053] First of all, in US 2014 / 083307 the climbing slopes interact with the locking mechanism, namely with the locking pins, and make the locking pins move upwards against the resistance of their springs.

[0054] Conversely, in the present invention, second resistance means are provided for offering an increased resistance to the rotation of the rotor relative to the stator, which second resistance means are separate and independent from the first resistance means acting on the actuating member and urging the locking mechanism to the locking configuration.

[0055] Therefore, the operation of the second resistance means is completely independent from the locking mechanism, and vice versa.

[0056] Secondly, in the present invention the second resistance means acts in the radial direction, so that their operation is independent from gravity, thus from the presence and entity of a weight arranged on the vehicle seat (such as a passenger).

[0057] According to a preferred embodiment of the invention, the stator is provided with a reinforcement ring having a substantially cylindrical shape, and the second resistance means are arranged on the inner surface of the reinforcement ring.

[0058] The provision of such reinforcement ring allows to increase the stiffness and the structural strength of the swiveling device, namely in case of frontal or lateral crashes.

[0059] According to an alternative embodiment of the invention, said reinforcement ring is replaced by a plurality of discrete elements, namely by a plurality of pairs of co-operating brackets.

[0060] Preferably, such pairs of co-operating brackets are as many as the locking positions and they are arranged at the locking positions or close thereto. In this way, the second resistance means can be arranged on these brackets.

[0061] Further features and advantages of the invention will become more evident from the detailed description of preferred embodiments thereof, given by way of non-limiting example, with reference to the attached drawings, in which:Fig.1a

[0062] is a schematic perspective view of a vehicle seat provided with a swiveling device according to the inventionFig.1b

[0063] is a schematic perspective view of another vehicle seat provided with a swiveling device according to the inventionFig.2

[0064] is a perspective view of the swiveling device according to a first embodiment of the inventionFig.3

[0065] is an exploded view of the swiveling device ofFig.4

[0066] shows, in a lateral view, a detail of the swiveling device of Figures 2 and 3 relating to the resistance means arrangement of such swiveling deviceFig.5

[0067] shows, in a top view, a further detail of the swiveling device of Figures 2 and 3 relating to the resistance means arrangement of such swiveling deviceFig.6

[0068] is a perspective view of the swiveling device according to a second embodiment of the inventionFig.7

[0069] shows, in a lateral view, a detail of the swiveling device ofrelating to the resistance means arrangement of such swiveling deviceFig.8

[0070] shows, in a top view, a further detail of the swiveling device ofrelating to the resistance means arrangement of such swiveling device.

[0071] A vehicle seat 100 is schematically shown in.

[0072] The vehicle seat 100 generally includes a seat cushion, including a seat cushion frame 102 and seat cushion foam body (not shown) mounted to the seat cushion frame, and a seat backrest, including a seat backrest frame 104 and seat backrest foam body (not shown) mounted to the seat backrest frame.

[0073] In a known manner, the seat cushion frame 102 is mounted on a pair of tracks 106. In detail, the seat cushion frame 102 is fastened to the upper rails 106a of the tracks 106, while the lower rails 106b of the tracks 106 are fixedly fastened to the vehicle floor 200, said upper rails being slidably connected to said lower rails.

[0074] The vehicle seat 100 is provided with a swiveling device 1 according to the invention, allowing the vehicle seat 100 to rotate relative to the vehicle floor 200 about a vertical direction Z, i.e. a direction that is substantially perpendicular to the vehicle floor 200.

[0075] The swiveling device 1 is interposed between the seat cushion frame 102 and the vehicle floor 200 and includes a stationary (i.e. non-rotating) portion and a rotating portion.

[0076] In the shown example, the stationary portion of the swiveling device 1 is connected to the upper rails 106a of the tracks 106, while the rotating portion of said swiveling device is connected to seat cushion frame 102.

[0077] Thanks to this arrangement, the swiveling device 1 as a whole can move with the vehicle seat 100, when, for instance, said vehicle seat slides along the tracks 106; at the same time, the vehicle seat 100 can rotate relative to the vehicle floor (for instance, when a user enters the vehicle cockpit or exits therefrom).

[0078] Another vehicle seat 100’ provided with a swiveling device 1 according to the invention is schematically shown in.

[0079] The overall construction of the vehicle seat 100’ is the same as disclosed with reference to.

[0080] In this further example, the stationary portion of the swiveling device 1 is directly connected to the vehicle floor, while the rotating portion of said swiveling device is connected to the lower rails 106b of the tracks 106.

[0081] Thanks to this arrangement, the vehicle seat 100’ can rotate together with the tracks 106 relative to the vehicle floor.

[0082] A swiveling device 1 according to a first embodiment of the invention is shown in greater detail in Figures 2 and 3.

[0083] The swiveling device 1 includes a stationary stator and a rotating rotor.

[0084] In the shown embodiment, the stator includes a lower stator plate 3a and an upper stator plate 3b, and the rotor includes a rotor plate 5 sandwiched between the lower and upper stator plates 3a, 3b.

[0085] A lower bearing ring 7a is provided between the lower stator plate 3a and the rotor plate, and an upper bearing ring 7b is provided between the rotor plate and the upper stator plate 3b.

[0086] The stator plates 3a, 3b, as well as the rotor plate 5, preferably have an overall substantially annular shape.

[0087] In greater detail, in the shown embodiment the lower stator plate 3a includes a peripheral annular rim 9 and it is coupled to a reinforcement ring 11. Such reinforcement ring 11 has a substantially cylindrical wall 13, upwardly projecting from the inner edge of the annular rim 9 of the lower stator plate 3a.

[0088] The rotor plate 5 includes a peripheral annular rim 15 and a cylindrical wall 17, downwardly projecting from the inner edge of the annular rim 15.

[0089] The upper stator plate 3b includes a peripheral annular rim 19.

[0090] The inner diameter of the stator, namely the inner diameter of the cylindrical wall 13 of the reinforcement ring 11 coupled to the lower stator plate 3a, is slightly larger than the outer diameter of the rotor, namely than the outer diameter of the cylindrical wall 17 of the rotor plate 5.

[0091] As a result, the cylindrical wall 17 of the rotor plate 5 can be received inside the cylindrical wall 13 of the reinforcement ring 11 and the rotor plate can rotate relative to the lower stator plate without friction.

[0092] A locking mechanism is provided for selectively locking and unlocking rotation of the rotor of the swiveling device relative to the stator of said swiveling device.

[0093] In the shown embodiment, such locking mechanism includes a locking member, such as a locking pin 21, and a plurality of discrete seats 23 suitable for receiving and firmly retaining said locking pin.

[0094] The locking member 21 is integral in rotation with the rotor, while the seats are arranged in the stator.

[0095] In the shown embodiment, the seats 23 are provided along the circumference of the peripheral annular rim 19 of the upper stator plate 3b, and they are uniformly distributed along the circumference of said peripheral annular rim 19.

[0096] More particularly, four discrete seats 23 are arranged at 90° from one another along the circumference of the peripheral annular rim 19 of the upper stator plate 3b.

[0097] This arrangement is particularly advantageous, as it allows, for instance, to rotate the vehicle seat over an angle of 90°, for passing from a first position, in which the seat is oriented towards the traveling direction of the vehicle, to a second position, in which the seat is oriented towards the adjacent vehicle door.

[0098] However, a different number of seats and / or a different distribution of such seats along the circumference of the swiveling device could also be envisaged.

[0099] It is to be noted that, according to a different embodiment of the invention, the locking mechanism could include a seat, integral in rotation with the rotor, and a plurality of discrete locking members (locking pins), arranged on the stator and suitable for being received and firmly retained in said seat.

[0100] In such embodiment, the locking pins would be provided along the circumference of the peripheral annular rim of the upper stator plate, and they would be uniformly distributed along the circumference of said peripheral annular rim.

[0101] Turning back to the embodiment shown in Figures 2 and 3, the locking mechanism further includes an actuating member, such as an actuating lever 25, for switching the locking pin 21 from a locking position, in which it is firmly held in one of the seats 23 and rotation of the rotor plate 5 relative to stator plates 3a, 3b is prevented, to an unlocking position, in which it is released from the seat 23 and rotation of the rotor plate 5 relative to stator plates 3a, 3b is allowed, and vice versa.

[0102] The actuating lever 25 switches the locking pin 21 from the locking position to the unlocking position by overcoming the resistance of first resistance means.

[0103] In the shown embodiment, the first resistance means are elastic means, such as a spring.

[0104] More in detail, in the shown embodiment, the actuating lever 25 that carries the locking pin is hinged to the rotor plate 5 at a pivoting pin 26 and is provided with a spring 27; when the spring 27 is in rest condition, the locking pin 21 is in its locking position.

[0105] By gripping the actuating lever 25 and overcoming the elastic resistance of the spring 27, the user can switch the locking pin 21 to its unlocking position. When the user releases the actuating lever 25, the elastic return force of the spring 27 brings back the locking pin 21 to its locking position.

[0106] As shown in the Figures, a bracket 29 is preferably provided on the rotor plate 5 for limiting the rotation of the actuating lever 25.

[0107] This bracket 29 advantageously protects the actuating lever 25 and the hinge about which it rotates, for instance in case of crashes.

[0108] In addition, said bracket 29 contributes to increase the overall stiffness of the swiveling device construction.

[0109] In order to obtain a smooth and comfortable operation of the swiveling device, it is strongly recommended that the user releases the actuating lever 25 and the locking pin 21 is brought back to its locking position when said locking pin 21 is at the angular position of one of the seats 23.

[0110] In this way, as soon as the user releases the actuating lever, the locking pin is received and firmly held in the corresponding seat 23 and rotation of the swiveling device is immediately stopped.

[0111] To this purpose, the swiveling device 1 according to the invention includes means for informing the user that they is approaching a seat 23, i.e. a selectable position for the vehicle seat, so that they can release the actuating lever at proper moment during rotation of the swiveling device.

[0112] More particularly, the swiveling device 1 includes second resistance means that generate friction and increase the resistance to the rotation of the rotor relative to the stator when said rotor, during its rotation, is approaching a seat 23.

[0113] The second resistance means 31 of the swiveling device 1 according to the invention are shown in detail in Figures 4 and 5.

[0114] In the shown embodiment, second resistance means 31 includes first resistance element(s) 31a provided on the rotor, namely on the rotor plate 5, and second resistance element(s) 31b provided on the stator, namely on the reinforcement ring 11, the first and second resistance elements 31a, 31b cooperating with each other for reducing the radial gap G between the rotor and the stator in proximity of the seats 23, so as to generate friction and increase the resistance to the rotation of the rotor relative to the stator when said rotor, during its rotation, is approaching a seat 23.

[0115] In greater detail, the first resistance element(s) provided on the rotor are implemented as a radially outwardly projecting elastic member 31a arranged on the outer surface of the cylindrical wall 17 of the rotor plate 5, and the second resistance element(s) provided on the stator are implemented as radially inwardly projecting bosses 31b arranged on the inner surface of the cylindrical wall 13 of the reinforcement ring 11.

[0116] Preferably, radially inwardly projecting bosses 31b are provided close to each seat 23, on either side thereof. Accordingly, in the shown embodiment, in which four discrete seats 23 are provided, eight radially inwardly projecting bosses 31b are provided on the reinforcement ring 11, a pair of bosses for each seat 23.

[0117] The radially outwardly projecting elastic member 31a and the radially inwardly projecting bosses 31b are sized so that the radial extension of said outwardly projecting elastic member 31a is smaller than the radial distance between the outer surface of cylindrical wall 17 of the rotor plate 5 and the inner surface of the cylindrical wall 13 of the reinforcement ring 11, but at the same time it is greater than the distance between the outer surface of cylindrical wall 17 of the rotor plate 5 and the inner surface of the inwardly projecting bosses 31b.

[0118] As evident from, thanks to this arrangement the rotor plate 5, with its radially outwardly projecting elastic member 31a, rotates without friction relative to the stator plates 3a, 3b and the reinforcement ring 11 as long as the locking pin 31 is far from a seat 23.

[0119] However, when the locking pin 31, during rotation of the rotor plate 5, is approaching a seat 23, the radially outwardly projecting elastic element 31a meets a corresponding radially inwardly projecting boss 31b, gets compressed and slithers against the surface of the boss.

[0120] As a result, friction is generated and the resistance to the rotation of the rotor relative to the stator is considerably increased, so that the user immediately perceives that a selectable position for the vehicle seat is being reached.

[0121] It is evident, that it could also be possible to provide the outer surface of the cylindrical wall 17 of the rotor plate with a radially outwardly projecting boss, and the inner surface of the cylindrical wall 13 of the reinforcement ring 11 with radially inwardly projecting elastic members in the proximity of the seats 23, preferably on either side thereof.

[0122] Nevertheless, provision of radially inwardly projecting bosses on the reinforcement ring 11 advantageously contributes to increase the overall stiffness and resistance to shocks of the swiveling device 1.

[0123] It is also evident, that it could also be possible to provide the outer surface of the cylindrical wall 17 of the rotor plate with multiple radially outwardly projecting elastic members (or with multiple radially outwardly projecting bosses, respectively), and the inner surface of the cylindrical wall 13 of the reinforcement ring 11 with multiple radially inwardly projecting bosses (or with multiple radially inwardly projecting elastic members, respectively).

[0124] By increasing the number of radially outwardly projecting elastic members (for instance up to four), it is possible to modify the value of the resistant torque and, therefore, of the friction feeling effect.

[0125] A swiveling device 1 according to a second embodiment of the invention is shown in Figures 6 – 8.

[0126] The construction of the swiveling device 1 is substantially the same as disclosed in connection with the first embodiment described above.

[0127] The swiveling device 1 of this second embodiment differs from the one of the first embodiment in that the annular reinforcement ring is replaced by a plurality of discrete elements, namely by a plurality of discrete pairs of co-operating brackets 12a, 12b.

[0128] Each pair of brackets includes a lower bracket 12a fastened to the lower stator plate 3a and a co-operating upper bracket 12b fastened to the upper stator plate 3b (as can also be seen in).

[0129] In this embodiment, too, second resistance means 31 are provided, which includes first resistance elements 31a provided on the rotor and second resistance elements 31b provided on the stator, close to each seat 23.

[0130] Accordingly, the pairs of brackets 12a, 12b are as many as the seats 23 and they are arranged at the locations of said seats 23 or close thereto. In this way, the second resistance elements 31b can be arranged on said brackets.

[0131] shows the first resistance elements (made as a radially outwardly projecting elastic member 31a) and the second resistance elements (made as radially inwardly projecting bosses 31b) arranged on the lower bracket 12a of a pair of brackets.

[0132] The construction and operation of the first and second resistance elements 31a, 31b is substantially the same as disclosed in connection with the first embodiment.

[0133] As can be seen in, in this embodiment the radially outwardly projecting elastic member 31a has a dome-shaped middle portion 31a’ and two V-shaped end portions 31a’’.

[0134] Advantageously, the V-shaped end portions 31a’’ can be compressed for being fitted into corresponding seats provided in the rotor, so that they are firmly locked into these seats as soon as they are released.

[0135] The domed shape of the middle portion 31a’ advantageously allow an increasing engagement with the inwardly projecting bosses 31b, so that a smoothly and progressively increasing friction feeling effect is obtained.

[0136] It will be evident from the above that the invention reaches the objects set forth above, since the construction of the swiveling device is easy and reliable and its operation is smooth and comfortable.

[0137] It will be also evident that the preferred embodiments shown in the figures and described in detail here above have been given by way of non-limiting example and many variants and modification are possible without departing from the scope of the invention as defined by the appended claims.

[0138] More particularly, the resistance means could be implemented in many other ways within the reach of the person skilled in the art, as long as they are suitable for generating friction and for increasing the resistance to the rotation of the swiveling device rotor relative to swiveling device stator.

Claims

Swiveling device (1) for a vehicle seat, including a stator (3a, 3b, 11), a rotor (5), rotatable relative to said stator and a locking mechanism (21, 23, 25) for selectively allowing or preventing rotation of said rotor relative to said stator, wherein said locking mechanism includes a first locking member (21) which is integral in rotation with said rotor, a plurality of discrete second locking members (23) arranged along the circumference of said stator and suitable for engaging and co-operating with said first locking member (21), and an actuating member (25) for switching said first locking member (21) from a locking position, in which it engages and co-operates with one of said second locking members (23) and rotation of said rotor relative to said stator is prevented, to an unlocking position, in which it is disengaged from said one of said second locking members (23) and rotation of said rotor relative to said stator is allowed, by overcoming the resistance of first resistance means (27), characterized in that second resistance means (31), separate and independent form said first resistance means (27) are provided along the circumference of said stator in the proximity of said discrete second locking members (23), such second resistance means generating friction and offering an increased resistance to the rotation of said rotor relative to said stator when said locking member (21) is approaching one of said second locking members (23).Swiveling device (1) according to claim 1, wherein said first resistance means (27) are elastic resistance means.Swiveling device (1) according to claim 1 or 2, wherein said second resistance means (31) include first resistance element(s) (31a) arranged on said rotor and second resistance element(s) (31b) arranged on the stator, said first and second resistance elements (31a, 31b) cooperating with each other for locally reducing the gap between the rotor and the stator.Swiveling device (1) according to claim 3, wherein said first resistance said first and second resistance elements (31a, 31b) cooperate with each other for locally reducing the gap in the radial direction between the rotor and the stator.Swiveling device (1) according to claim 4 wherein said first resistance elements include at least one radially outwardly projecting elastic member (31a) provided on a surface of said rotor facing said stator, and said second resistance elements include radially inwardly projecting bosses (31b) provided on a surface of said stator facing said rotor.Swiveling device (1) according to claim 5, wherein, for each of said second locking members (23), at least one pair of radially inwardly projecting bosses (31b) are provided, the radially inwardly projecting bosses of each pair of radially inwardly projecting bosses being arranged on either side of said second locking member.Swiveling device (1) according to claim 5 or 6, wherein the radial extension of said at least one radially outwardly projecting elastic element (31a) is smaller than the radial distance between said surface of said rotor facing said stator and said surface of said stator facing said rotor, but greater than the radial distance between said surface of said rotor facing said stator and the surface of said radially inwardly projecting bosses (31b).Swiveling device (1) according to claim 4, wherein said first resistance elements include at least one radially outwardly projecting boss provided on a surface of said rotor facing said stator, and said second resistance elements include inwardly projecting elastic members provided on a surface of said stator facing said rotor, the radial extension of said at least one radially outwardly projecting boss being smaller than the radial distance between said surface of said rotor facing said stator and said surface of said stator facing said rotor, but greater than the radial distance between said surface of said rotor facing said stator and the surface of said inwardly projecting elastic members.Swiveling device (1) according to any of claims 1 to 8, wherein said first locking member is made as a locking pin (21) and said second locking members are made as discrete seats (23) arranged along the circumference of said stator and suitable for receiving said locking pin (21).Swiveling device (1) according to any of claims 1 to 8, wherein said first locking member is made as a locking seat and said second locking members are made as discrete locking pins arranged along the circumference of said stator and suitable for being receiving in said seat.Swiveling device (1) according to any of claims 1 to 10, wherein said stator includes a lower stator plate (3a), an upper stator plate (3b), and said rotor includes a rotor plate (5) sandwiched between said lower and upper stator plates (3a, 3b).Swiveling device (1) according to claim 11, wherein said actuating member of said locking mechanism is made as an actuating lever (25) hinged to said rotor plate, and said first locking member of said locking mechanism is carried by said actuating lever (25).Swiveling device (1) according to claim 11, wherein said upper stator plate (3b) includes a peripheral annular rim (19) and said discrete second locking members (23) of said locking mechanism are provided along the circumference of said peripheral annular rim (19) of said upper stator plate (3b), said second locking members (23) being preferably uniformly distributed along the circumference of said peripheral annular rim (19) of said upper stator plate (3b).Swiveling device (1) according to claims 3, wherein said stator includes a lower stator plate (3a), an upper stator plate (3b), and said rotor includes a rotor plate (5) sandwiched between said lower and upper stator plates (3a, 3b), wherein said stator comprises an annular reinforcement ring (11) or a plurality of pairs of brackets (12a, 12b) discretely arranged along the circumference of said stator and wherein said first resistance element(s) (31a) is / are provided on the outer surface of said cylindrical wall (17) of said rotor plate (5), and said second resistance element(s) (31b) is / are provided on said reinforcement ring (11) or on a bracket (12a) of each pair of brackets (12a, 12b) .Swiveling device (1) according to any of the preceding claims, wherein four discrete second locking members (23) arranged at 90° from one another are provided.Vehicle seat (100) provided with a swiveling device (1) according any of the claims 1 to 15

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