Seat rotation limiter

Abstract

A seat assembly having a seat structure supported on a base structure and having a rotation mechanism allowing the seat structure to pivot includes a seat rotation limiter that limits a rotation angle of a seat according to a fore-aft position of the seat structure. The limiter comprises a rotation stop connected to the seat structure for pivoting with the seat structure, and a plate connected to the seat structure and arranged to be contacted by the rotation stop after the seat structure is pivoted through a predetermined rotation limit angle, thereby preventing further rotation of the seat structure. In another aspect, the rotation stop and the plate are configured to provide different rotation limiting angles depending on the fore-aft position of the seat.

Description

This invention patent application is a divisional application of the Chinese invention patent application with the application date of August 16, 2019, the application name of "Seat Rotation Limiter", and the application number of 201980039366.0 submitted by the applicant. Technical Field

[0001] The present invention relates to adjustable seats, and more particularly, to a swivel seat in a vehicle. Background Art

[0002] Adjustable and swivel vehicle seats are commonly and widely used today. These seats are widely used in agricultural vehicles because such vehicles often tow implements or attachments, and passengers frequently rotate or turn in order to visually monitor such implements or attachments that are typically located behind the vehicle. These seats are also typically adjustable in the fore-and-aft direction to accommodate different passengers or different operating positions. In a vehicle such as a tractor, the steering wheel, brakes, and other control mechanisms are typically disposed at the front of the vehicle for use when the passenger is in the forward position.

[0003] Since timely access to these control mechanisms is a safety issue, it is desirable to limit the degree to which the seat can rotate such that the passenger cannot rotate too far beyond these control mechanisms. Accordingly, it is desirable to allow the passenger to rotate the seat to a certain extent to accommodate the passenger's need to view the rear area of the vehicle, but this rotation is limited such that access to these control mechanisms is readily available when needed.

[0004] In addition, different degrees of rotation or turning may be desirable depending on the fore-and-aft position of the seat. It is further desirable to allow adjustment of the position of different degrees of rotation or turning to accommodate the passenger's preference. Summary of the Invention

[0005] In one aspect, a seat assembly includes: a seat structure configured to receive a passenger sitting thereon, a base structure for supporting the seat structure on a surface, and a rotation mechanism between the seat structure and the base structure for allowing the seat structure to pivot relative to the base structure. In one aspect of the present invention, a seat rotation limiter that limits the rotation angle of the seat is provided. The limiter may include a rotation stop connected to the seat structure to pivot therewith, and a plate connected to the base structure and arranged to be contacted by the rotation stop after the seat structure pivots through a predetermined rotation limit angle, thereby preventing further rotation of the seat structure. In a further aspect, the seat assembly includes a rail assembly configured to allow fore-and-aft movement of the seat structure relative to the base structure, and the rotation stop and the plate are configured to provide different rotation limit angles depending on the fore-and-aft position of the seat. Brief Description of the Drawings

[0006] Figure 1 is a partial cross-sectional view of a seat assembly incorporating the rotary stop of the present invention.

[0007] Figure 2 is Figure 1 a front view of a portion of the base and rotary mechanism of the seat assembly of

[0008] Figure 3 is Figure 2 a partial top perspective cross-sectional view of the seat assembly shown in

[0009] Figure 4 is Figures 1 - 3 a perspective partial cross-sectional view of the base of the seat assembly shown in

[0010] Figure 5 is Figures 1 - 3 a perspective partial cross-sectional view of the base of the seat assembly shown in

[0011] Figure 6 is Figures 1 - 3 a perspective view of the underside of the seat structure of the seat assembly shown in

[0012] Figures 7(a), 7(b) are top views of the rotary stop incorporated into the Figures 1 - 3 seat assembly shown in

[0013] Figure 8 is incorporated in Figures 1 - 3 a top view of the plate of the rotary stop in the seat assembly shown in Detailed Description

[0014] For purposes of facilitating an understanding of the principles of the present invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is to be understood that no limitation of the scope of the present invention is thereby intended. It is further understood that the present invention includes any variations and modifications of the illustrated embodiments and further applications of the principles of the present invention as would normally occur to one of ordinary skill in the art to which the present invention pertains.

[0015] Figure 1The seat assembly S shown includes mechanisms that allow the seat to move or be adjusted in multiple degrees of freedom. The assembly includes a base structure 12, which can be any type of base structure or mounting bracket commonly known and used in the industry to secure the seat structure 14 to a vehicle. Typically, such a base structure 12 includes a suspension element 18 that allows adjustment of the height of the seat along direction V and provides shock or vibration damping characteristics. In Figure 1 the seat assembly S shown, the suspension element is a scissor-type mechanism. The base structure 12 includes an upper chassis 20 having flanges 22 on each side, the flanges providing a mounting surface for a rail assembly 24 that allows the seat structure 14 to move in the front-to-back direction F. The rail assembly 24 can be a two-piece design having a moving rail 24a associated with the seat structure and a fixed rail 24b associated with the base structure 12. However, other rail assemblies or similar mechanisms that allow front-to-back movement can also be used.

[0016] Referring Figures 2 - 3 , the seat assembly S further includes a rotation mechanism 25 that allows rotation or pivoting P of the seat structure 14 about the central axis A of the seat structure. The seat structure 14 includes a seat plate 32, and below the seat plate is a seat rotation ring 34 that includes a plurality of cage roller bearings 34a. The seat rotation ring 34 is clamped between the seat plate 32 and a lower rotating seat ring 36 to form the rotation mechanism 25. The seat plate 32 includes a central hub 37 that extends through an opening in the rotation ring 34 and a lower rotating seat ring 36 for centering the rotation mechanism. The lower rotating seat ring 36 is mounted to the moving rail 24a of the rail assembly 24 supported on the upper chassis. The rail assembly 24 allows the lower rotating seat ring 36, the seat rotation ring 34, and the seat plate 32 to move front-to-back, which thus provides front-to-back movement of the seat structure 14. It can be appreciated that the seat assembly can rotate or pivot at any front-to-back position of the seat structure 14 relative to the base structure 12. The rotation mechanism can be of the type disclosed in U.S. Patent No. 5,482,354, issued January 19, 1996.

[0017] Turning Figures 4 - 5, the upper chassis 20 is generally a rectangular frame having two side flanges 22 extending front and back. The mounting bracket 28 is mounted to one of the flanges 22 adjacent thereto, preferably to the chassis of the flange on the outer side of the seat assembly S for easy access. The mounting bracket 28 can be mounted to the frame by any suitable means including welding or using fasteners. In one aspect, the mounting bracket 28 is positioned below the edge 26 so as to support the plate 30, wherein the top surface 30a of the plate is flush with or slightly lower than the edge 26. In other words, the mounting bracket 28 and the plate 30 are configured to be contained within the housing of the upper chassis 20 so as not to interfere with other components and mechanisms of the seat assembly S. The plate 30 can be attached to the mounting bracket 28 by any suitable means including welding or fasteners. In one aspect, the rotation stop bracket 30 is attached to the mounting bracket 28 by bolts that are countersunk to be flush with the top surface 30a of the plate 30. It can be appreciated that the mounting bracket 28 and the plate 30 do not need to be formed of separate components and can be an integral structure. However, as Figures 4 - 5 shown, the two-piece design has the advantage of allowing easier replacement of the plate 30.

[0018] The plate 30 is part of a rotation stop device that limits the angular range allowing the seat structure 14 to rotate or pivot. The plate 30 thus forms a fixed part of the rotation stop device. The rotation stop 38 is mounted on the seat plate 32 so as to rotate or pivot together with the seat plate, and thus causes the seat structure 14 to rotate or pivot relative to the base structure 12. In one embodiment, the rotation stop 38 includes a central plate 39 that is mounted to the central hub 37 such that the rotation stop is positioned below the lower rotating seat ring 36 and more specifically is positioned aligned with the inner edge 31 of the plate 30, as Figure 2 described. In one embodiment, the central plate 39 of the rotation stop 38 can be fastened to the bottom of the central hub 37 by the same fasteners used to fix the central hub to the seat plate 32.

[0019] As Figure 6 shown in more detail, the rotation stop 38 includes an arm 40 extending from the central plate 39 of the rotation stop toward the fixed plate 30. The arm 40 can include a knob 41 adapted to contact the edge 31 of the plate 30. Thus, the rotation stop is mounted such that when the seat 14 is rotated or pivoted, the rotation stop 38 rotates therewith until the knob 41 contacts the inner edge 31 of the fixed plate 30. In this way, the rotation angle is limited to prevent a passenger sitting in the seat assembly S from pivoting the seat excessively.

[0020] In one aspect of the seat assembly 10, the inner edge 31 of the plate 30 includes two segments 31a and 31b as shown in FIGS. 7(a) and 7(b), and the two segments 31a and 31b can be contacted by the rotary stopper 38 according to the front - rear position of the seat structure 14. In particular, the segment 31a is slightly recessed relative to the segment 31b. Corresponding to the rearmost position of the seat, the segment 31a is adjacent to the rear edge 30a of the plate 30. Corresponding to the foremost position of the seat, the segment 31b extends from the recessed segment 31a to the front edge 30b of the plate. Thus, the recessed position of the segment 31a is arranged such that the knob 41 of the rotary stopper 38 engages the recess only when the seat structure is in its rearmost position. In all other positions, the knob of the rotary stopper 38 contacts the edge segment 31b. The recessed segment 31a is further configured such that the rotary stopper 38 can pivot or rotate at a greater angle compared to the edge segment 31b. In other words, the pivot - angle limit depends on the position on the edge 31 where the rotary stopper 38 contacts the edge. When the seat structure 14 is in its rearmost position, as depicted in FIG. 7(a), the seat structure 14 can pivot through a greater angle compared to the situation if the seat were in front of this position, as depicted in FIG. 7(b). In a specific embodiment, the recessed edge segment 31a is configured such that the rotary stopper 38 contacts the edge segment 31a after the seat rotates or pivots 50°. On the other hand, the non - recessed edge segment 31b is configured such that the seat and thus the rotary stopper can only rotate to a rotational limit angle of 40°.

[0021] It is contemplated that the plate 30 is configured for removal and replacement by disconnecting it from the mounting bracket 28 or by removing the plate together with the mounting bracket. As Figure 8 shown, a new plate 30f having a different configuration for the edge 31' can be installed onto the frame 20. In this specific embodiment, the plate 30' includes two recessed edge segments 31af and 31bf and a non - recessed edge segment 31c'. The two recessed edge segments 31a', 31bf are recessed to different depths such that the rotary stopper 38 contacts each segment at a different rotation angle. Other configurations of the edges 31, 31f are contemplated, including continuous edges having angled or gradually curved configurations.

[0022] It should be understood that the present disclosure is illustrative in many respects. Changes can be made in details, particularly in the shape, size, and arrangement of steps, without departing from the scope of the invention. Of course, the scope of the invention is defined in the language expressing the appended claims.

Claims

1. A seat assembly, comprising: a seat structure configured to support an occupant; a base structure; a rotation mechanism configured to allow the seat structure to pivot relative to the base structure about a substantially vertical axis; a rotation stopper mounted to the seat structure and configured to pivot with the seat structure; and a stop plate mounted to the base structure and configured to be contacted by the rotation stopper after the seat structure pivots through a predetermined rotation limit angle, thereby preventing further pivotal rotation; wherein the rotation stopper and the stop plate are configured such that the rotation angle at which the rotation stopper contacts the stop plate varies according to the front - rear position of the seat structure relative to the base structure.

2. The seat assembly according to claim 1, wherein, The stop plate includes a plurality of engagement surfaces corresponding to different rotation angles and configured to be contacted by the rotation stopper according to the front - rear position of the seat structure.

3. The seat assembly according to claim 1 or 2, wherein, The rotation stopper includes an arm radially extending from a central mounting plate located below the seat structure, and the arm includes a contact portion that engages with the stop plate.

4. The seat assembly according to any one of the preceding claims, further comprising a guide rail assembly disposed between the seat structure and the base structure, the guide rail assembly being configured to allow the front - rear translation of the seat structure.

5. The seat assembly according to any one of the preceding claims, wherein, The stop plate includes a recessed portion and a non - recessed portion, each portion defining a different rotation stop angle when contacted by the rotation stopper.

6. The seat assembly according to any one of the preceding claims, wherein, The stop plate is replaceable with another stop plate having a different engagement profile to modify the rotation limit angle.

7. A method of restricting pivotal rotation in a seat assembly, the method comprising: providing a seat structure pivotally mounted to a base structure via a rotation mechanism, a rotation stopper attached to the seat structure and configured to rotate with the seat structure, and a stop plate attached to the base structure and arranged to engage with the rotation stopper; adjusting the front - rear position of the seat structure relative to the base structure; wherein the angular range of seat rotation is restricted by the contact between the rotation stopper and the stop plate, and the rotation limit angle varies according to the front - rear position of the seat structure.

8. The method according to claim 7, further comprising: Engaging a protrusion on the distal end of the arm of the rotation stopper with a profiled edge of the stop plate.

9. The method according to claim 7 or 8, wherein The stop plate includes a recessed edge segment and a non - recessed segment, each segment defining a different rotation stop angle.

10. The method according to any one of the preceding method claims, further comprising: Replacing the stop plate with another plate having a different profiled edge to modify the rotation limit angle.

11. The method according to any one of the preceding method claims, wherein, The rotation mechanism includes a rotating ring disposed between a seat plate and a lower rotating seat ring, and a hub extending through the rotating ring and the seat ring.

12. The method according to claim 11, wherein, The rotation stopper is mounted to the hub on the side of the lower rotating seat ring opposite to the seat plate.

13. The method according to claim 7 further comprises: Construct the stop plate and the rotation stopper such that the inner edge of the stop plate is contacted by the rotation stopper to prevent further pivoting or rotation of the rotation stopper.

14. The method according to any one of the preceding method claims, further comprising: When in the rear position, the rotation stopper contacts the stop plate when rotated 50 degrees; in other positions, the rotation stopper contacts the stop plate when rotated 40 degrees.

15. The method according to any one of the preceding method claims, wherein, Provide the front - rear movement of the seat structure through a guide rail assembly connected between the seat and the base structure.

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