Seat assembly with inner seat back movable with a seat cushion

Abstract

A seat assembly includes a seat cushion and a seat back. The seat cushion has opposite front and rear ends. The seat cushion is selectively height adjustable relative to the floor of the vehicle. The seat back has nested outer and inner support members. The outer support member has an upper portion extending between spaced apart side bolsters. The inner support member is disposed between the side bolsters and below the upper portion of the outer support member. The inner support member is operatively coupled to the seat cushion for movement therewith relative to the outer support member. The inner support member remains below the upper portion of the outer support member to provide continuous support to the lower portion of the occupant's back during adjustment of the seat cushion relative to the floor of the vehicle.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to seat assemblies for motor vehicles. More particularly, the invention relates to a seat back having an inner seat back independently movable with respect to an outer seat back.

2. Description of the Related Art

A motor vehicle includes at least one seat assembly for supporting an occupant within a passenger compartment of the motor vehicle. The seat assembly includes a seat cushion and a seat back for supporting the torso of an occupant seated on the seat cushion. Typically, the seat back is pivotable relative to the seat cushion between a plurality of seating positions. Further, the seat assembly is typically mounted to a floor mounted seat adjuster that allows horizontal and vertical comfort adjustment of the seat cushion and seat back together relative to the floor of the vehicle.

Some seat assembly designs, commonly referred to as “All Belt to Seat” (ABTS) designs, include belt restraint devices incorporated into the seat structure. Vehicle manufacturers desire ABTS designs for a variety of reasons, such as reduced complexity in the assembly of the vehicle, improved comfort due to the more proximal location of the belt exit point relative to the occupant, and packaging concerns related to a particular vehicle design.

The seat back in a conventional ABTS design typically includes at least one reinforced side member that bears the majority of the forces or “belt loads” associated with the restraint device. Due to the potential magnitude of the belt loads, the reinforced side member is coupled directly to the horizontal rails of the seat adjuster. As a result, the seat back in a conventional ABTS design is not vertically adjustable with the seat cushion.

It, therefore, remains desirable to provide an ABTS design having a seat back, or at least a portion thereof, movable with the seat cushion to provide proper back support of the occupant through the adjustment range of the seat cushion.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a seat assembly is provided for supporting an occupant above a floor of a motor vehicle. The seat assembly includes a seat cushion, an adjuster assembly and a seat back. The seat cushion has opposite front and rear ends. The adjuster mechanism is operatively coupled between the floor of the motor vehicle and the seat cushion. The adjuster mechanism allows selective horizontal and vertical adjustment of the seat cushion relative to the floor. The seat back assembly includes an outer frame, an inner frame, an outer foam pad and an inner foam pad. The inner frame has an upper end slidably and pivotally coupled to the outer frame. The inner frame has a lower end pivotally coupled to the seat cushion. The outer foam pad is fixedly secured to the outer frame. The outer foam pad has an upper portion extending between spaced apart side bolsters. The inner foam pad is disposed between the side bolsters and below the upper portion of the outer foam pad. The inner foam pad is fixedly secured to the inner frame for vertical and pivotal movement relative to the outer foam pad in response to corresponding vertical and pivotal movement of the seat cushion relative to the floor.

According to another aspect of the invention, the seat assembly includes a seat cushion and a seat back. The seat cushion has opposite front and rear ends. The seat cushion is selectively height adjustable relative to the floor of the vehicle. The seat back has nested outer and inner support members. The outer support member has an upper portion extending between spaced apart side bolsters. The inner support member is disposed between the side bolsters and below the upper portion of the outer support member. The inner support member is operatively coupled to the seat cushion for movement therewith relative to the outer support member. The inner support member remains below the upper portion of the outer support member to provide continuous support to the lower portion of the occupant's back during adjustment of the seat cushion relative to the floor of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a front perspective view of a seat assembly according to an embodiment of the invention;

FIG. 2 is a perspective view of an adjuster assembly for the seat assembly;

FIGS. 3-8 are perspective views of the seat assembly of FIG. 1 illustrating the various positions of the seat cushion and seat back of the seat assembly;

FIGS. 9 and 10 are front perspective views of another embodiment of the invention with the seat cushion and inner support member shown in vertically lowered and elevated positions, respectively; and

FIGS. 10 and 11 are front perspective views of a frame structure for moving the seat cushion and inner support member together relative to the outer support member of the seat back.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a seat assembly for a motor vehicle is generally indicated at 10. The seat assembly 10 includes a generally horizontal seat cushion 12, a generally upright seat back 14, and a head restraint 16 fixedly secured to a top portion of the seat back 14. The seat assembly 10 also includes an adjuster mechanism 20 coupled between a bottom surface of the seat cushion 12 and the floor of the vehicle allowing selective vertical adjustment of the seat cushion 12 relative to the floor. Described in greater detail below, the seat back 14 includes an inner frame coupled to the seat cushion 12 for movement therewith to provide optimal support of the occupants back during adjustment of the seat cushion 12 relative to the floor of the vehicle.

Referring to FIG. 2, the adjuster mechanism 20 includes opposite and spaced apart inboard 21 and outboard 22 sides. Each side of the adjuster mechanism 20 includes a lower track 24 and an upper track 26. The lower track 24 is fixedly secured to the floor of the vehicle. The upper track 26 is slidably coupled to the lower track 24 for generally forward and rearward movement of the upper track 26 relative to the floor of the vehicle. A bottom support frame 36 for supporting the seat cushion 12 is operatively coupled to the upper track 26 for vertical movement of the bottom support frame 36 and seat cushion 12 relative to the upper track 26. A first support member 30 and a second support member 32 are mounted to the upper track 26 on the outboard side 22. A load transfer member or beam 34 is fixedly secured to the first 30 and second 32 support members.

Preferably, the horizontal movement of the upper track 26 relative to the lower track 24 and the vertical movement of the bottom support frame 36 relative to the upper track 26 are driven by electric motors, which are generally indicated at 40. A more detailed description of the adjuster mechanism 20 and its operation are disclosed in U.S. Pat. No. 6,089,665, the content of which is incorporated herein by reference in its entirety.

Referring back to FIG. 1, the seat back 14 includes an outer frame 50 and an inner frame 60. The outer frame 50 has generally parallel and spaced apart side members 52 each extending between opposite upper and lower ends. The outer frame also has a cross member 56 that extends between the upper ends of the side members 52. The lower ends of the side members 52 are fixedly secured to respective upper tracks 26 by recliner mechanisms 58 providing pivotal movement of the seat back 14 relative to the upper track 26 about a recline axis 28. Preferably, the recliner mechanisms 58 are continuously engaged rotary recliners, as known by those of ordinary skill in the art. Most preferably, the recliner mechanisms 58 are driven by electric motors (not shown). The inner frame 60 is adapted to fit in the space defined between the side members 52. The inner frame 60 has sides 62 generally parallel with the side members 52 of the outer frame 50.

Each frame 50, 60 is covered by a foam pad concealed by a cut and sewn trim cover. The foam pads are shaped to substantially follow the shape of the respective underlying frames 50, 60. Generally, the foam pads provide an occupant supporting surface for each frame 50, 60. Preferably, bolsters 54 for supporting the sides of the occupant's torso are defined in the foam pad extending along the side members 52; and a lumbar support 64 is defined in the foam pad covering the inner frame 60.

Slots or grooves 70 are formed in the side members 52. Optionally, tracks having grooves are fixedly secured to the side member 52. The grooves 70 define a path of movement for the inner frame 60. The path can be linear, arcuate, or a combination thereof. Preferably, the path is substantially parallel with the side members 52. The inner frame 60 is slidably coupled to the side members 52 of the outer frame 50 for movement along the path. More specifically, pins 72 extend outwardly from the sides 62 of the inner frame 60, which are slidably engaged with the respective grooves 70 of the side members 52. A bottom edge 74 of the inner frame 60 is pivotally coupled to a rear end of the seat cushion 12 for movement about a pivot axis 76. Vertical adjustment of the seat cushion 12 causes corresponding sliding movement of the inner frame 60 relative to the outer frame 50 along the path defined by the grooves 54. By this arrangement, the lumbar support 64 on the inner frame 60 can remain in close proximity to the lumbar region of the occupant as the seat cushion 12 is vertically and/or horizontally adjusted. The pivot axis 76 defined between the inner frame 60 and the seat cushion 12 is generally parallel with and spaced apart from the recline axis 28 of the outer frame 50. The pins 72, therefore, allow the inner frame 60 to slide and pivot relative to the outer frame 50 during pivotal movement of the outer frame 50 about the recline axis 28 to accommodate the spaced relation between the recline axis 28 of the outer frame 50 and the pivot axis 76 between the inner frame 60 and the seat cushion 12.

Optionally, longitudinally extending flanges along the sides 62 of the inner frame 60 are slidably engaged with the grooves 70 instead of the pins 72, so that movement of the inner frame 60 is limited to sliding movement along the path defined by the grooves 70. In this case, the pivotal connection between the bottom edge 74 of the inner frame 60 can include a lost motion arrangement, such as a pin and slot design, to accommodate the spaced relation between the recline axis 28 of the outer frame 50 and the pivot axis 76 between the inner frame 60 and the seat cushion 12 during movement of the outer frame 50 about the recline axis 28. Alternatively, rearward reclining adjustment of the outer frame 50 can be limited by design, thereby obviating the need to address the spaced relation between the recline axis 28 of the outer frame 50 and the pivot axis 76 between the inner frame 60 and the seat cushion 12.

Optionally, the top portion of inner frame 60 can be fixedly secured to the top portion of outer frame 50, while the bottom part of frame 60 is allowed to flex or stretch and remain connected with seat cushion 12 during rotation of the outer frame 50 about the recline axis 28.

In another embodiment of the invention, the head restraint 16 is fixedly secured to the top portion of the inner frame 60 for sliding movement therewith relative to the outer frame 50. Alternatively, the head restraint 16 can be mounted to a top portion of the outer frame 50 and, therefore, not move with the inner frame 60 during vertical adjustment of the seat cushion 12.

In use, the occupant can adjust the seat cushion 12 between a down position, as shown in FIG. 4, an up position, as shown in FIG. 6, and any one of a plurality of vertical positions therebetween, as illustrated by the middle position shown in FIG. 5. The seat back 14 will follow vertically with the rear end of the seat cushion 12 among these aforementioned vertical positions. The seat back 14 also follows the vertical displacement of the rear end of the seat cushion 12 as the seat cushion 12 is tilted between the base position of FIG. 7 and the tilted position of FIG. 8.

In another embodiment of the invention, the seat assembly 10 is an ABTS seat incorporating the aforementioned outer 50 and inner 60 frame construction. At least one of the side members 52 of the outer frame 50, i.e. the side member 52 that is outboard with respect to the vehicle, comprises a tower member 80 adapted to withstand torsional and bending forces or loads associated with the weight of the occupant against a seat belt 81 during a sudden deceleration of the vehicle. The belt retractor 82 is fixedly secured to any suitable location on the seat assembly 10, such as within the tower member 80 or to a bracket depending from the outer frame 50 of the seat back 14. The belt is guided by a spool through an opening or belt exit 84 defined along a front face of the tower 80. The free end of the belt is fixedly secured to the upper track 26, on the same side of the seat assembly as the tower 80. Optionally, the belt exit 84 is defined in a bezel (not shown) that is movably adjustable in a longitudinal sense along the tower 80.

In FIGS. 9-10, a second embodiment of the seat assembly is shown, wherein like elements are indicated by numerals offset by 100. In this embodiment, the seat back 114 has an outer support member or foam pad that has a generally inverted U-shape defined by an upper portion 53 and spaced apart bolsters 154 extending downwardly from opposite sides of the upper portion 53. An inner support member or foam pad 164 is disposed between the bolsters 154 and below the upper portion 53. The head restraint 116 is supported along a top surface of the upper portion 53.

Referring now to FIGS. 11-12, the outer foam pad is supported by the outer frame 150. The inner foam pad 164 is supported by the inner frame 160. The inner frame 160 is slidably coupled to the side members 152 of the outer frame 150. More specifically, a pair of tracks 90 is fixedly secured to respective side members 152 of the outer frame 150. Each track 90 has a generally U-shaped cross section defined by a main wall 92 and spaced apart side walls 94 extending substantially orthogonally from opposite sides of the main wall 92. A pair of sliding members or rollers 95 is fixedly secured to opposite sides of the inner frame 160. The sliding members 95 are engaged with respective tracks 90 on the side members 152 to allow both sliding and pivotal movement of the inner frame 160 relative to the outer frame 150.

The bottom end of the inner frame 160 is pivotally coupled to the seat cushion 112 by a pivot pin 172. The pivotal connection between the inner frame 160 and the seat cushion 112 allows the inner frame 160 and the inner foam pad 164 to move with the seat cushion 12 as it is adjusted in vertical and/or horizontal directions. Thus, the inner foam pad 164 provides proper support of the occupant's lumbar region in any of the vertical and horizontal positions of the seat cushion 12.

The inner frame 160 includes generally parallel and spaced apart sides. A suspension 180 extends between the sides of the inner frame 160. It should be appreciated that any suitable suspension known by those skilled in the art can be supported by the sides of the inner frame 160, such as an adjustable lumbar support mechanism. Additionally, the suspension 180 can be oriented in a generally vertical manner between the opposite top and bottom ends of the inner frame 160 rather than the horizontal manner shown in FIGS. 11 and 12.

The invention has been described in an illustrative manner. It is, therefore, to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. For example, the sides of the inner frame 160 are shown as straight. Those skilled in the art should, however, readily appreciate that the sides of the inner frame 160 can have any shape necessary to achieve a desired level of support while remaining within the packaging constraints of the particular outer seat design. Thus, within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

1. A seat assembly for supporting an occupant above a floor of a motor vehicle, the seat assembly comprising: a seat cushion having opposite front and rear ends; an adjuster mechanism operatively coupled between the floor of the motor vehicle and the seat cushion, the adjuster mechanism allowing selective horizontal and vertical adjustment of the seat cushion relative to the floor; and a seat back assembly having: an outer frame; an inner frame having an upper end slidably and pivotally coupled to the outer frame, the inner frame having a lower end pivotally coupled to the rear end of the seat cushion; an outer foam pad fixedly secured to the outer frame, the outer foam pad having an upper portion extending between spaced apart side bolsters; an inner foam pad disposed between the side bolsters and below the upper portion of the outer foam pad, the inner foam pad being fixedly secured to the inner frame for vertical and pivotal movement relative to the outer foam pad in response to corresponding vertical and pivotal movement of the seat cushion relative to the floor.

2. The seat assembly as set forth in claim 1, wherein the outer frame includes a pair of side members that are generally parallel and spaced apart, at least one of the side members having a track fixedly secured thereto and slidably engaged with the inner frame.

3. The seat assembly as set forth in claim 2 including a suspension extending between generally parallel and spaced apart sides of the inner frame for movement therewith relative to the outer frame.

4. The seat assembly as set forth in claim 3, wherein both sides of the inner frame are pivotally coupled to the seat cushion by a pivot rod.

5. The seat assembly as set forth in claim 1 including a head restraint slidably coupled to the outer frame for selective height adjustment relative to the upper portion of the outer foam pad.

6. A seat assembly for supporting an occupant above a floor of a motor vehicle, the seat assembly comprising: a seat cushion having opposite front and rear ends, the seat cushion being selectively height adjustable relative to the floor of the vehicle; a seat back with nested outer and inner support members, the outer support member having an upper portion extending between spaced apart side bolsters, the inner support member being disposed between the side bolsters and below the upper portion of the outer support member, the inner support member being operatively coupled to the seat cushion for movement therewith relative to the outer support member, the inner support member remaining below the upper portion of the outer support member to provide continuous support to the lower portion of the occupant's back during height adjustment of the seat cushion relative to the floor of the vehicle.

7. The seat assembly as set forth in claim 6, wherein a lower end of the inner support member is pivotally coupled to the seat cushion.

8. The seat assembly as set forth in claim 7, wherein the seat cushion is independently horizontally adjustable relative to the outer support member of the seat back.

9. The seat assembly as set forth in claim 8, wherein an upper end of the inner support member is slidably and pivotally coupled to the outer support member accommodating movement of the inner support member together with the seat cushion during height and horizontal adjustment of the seat cushion relative to the outer support member.

10. The seat assembly as set forth in claim 6 including a head restraint supported by the outer support member of the seat back.