Patent Publication Number: US-11654808-B2

Title: Seat assembly having compression limiter with wave portion

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. Non-Provisional Application Ser. No. 16/965,145 entitled “Seat Assembly having Compression Limiter with Wave Portion” filed Jul. 27, 2020, which represents the United States national stage filing of PCT/US2019/019237, filed Feb. 22, 2019, which claims the benefit of U.S. Provisional Application No. 62/633,949, entitled “Seat Assembly having Compression Limiter with Wave Portion,” with a filing date of Feb. 22, 2018. 
    
    
     BACKGROUND 
     The following description relates to an adjustable seat assembly for use in automotive applications, office furniture and recreational vehicle seating. 
     Automotive seating designs have traditionally used common materials and processes across manufacturers. Known seating designs typically include steel frames, steel suspensions and compression limiters, accompanied by fabric or leather trim covers. Compression limiters are most commonly implemented in automotive seating as foam layers. Compression limiters are used to distribute reaction forces, diffuse occupant stress spikes and offer controlled deflection under forces resulting in energy absorption. 
     In known automotive seating designs, the commonly used foam layers, as compression limiters, have been found suitable for providing comfort and load distribution, observable in pressure map testing. The comfort of foamed seating (i.e., seating designs including the foam layers) is determined, at least in part, by the foam durometer, thickness and porosity to control indentation force deflection (IFD), which is a commonly used measurement to judge and control comfort. The foamed materials of the foam layers are typically thermoset materials. 
     Some automotive seating designs include additional features such as seat heating and/or cooling devices. The heating and cooling devices may include resistive electrical circuitry (for heating) and related electrical component such as wire harnesses and the like, Peltier thermo-electric generators, blowers, fans and the like. In some seating designs, a vacuum generated by a fan blower can provide a cooling sensation to the occupant by pulling air and moisture from the occupant through the seat using a manifold system through the foam layers. In some instances, seating designs include further components configured to dampen buzz, squeak and rattle (BSR) of the fan blowers. 
     Known automotive seating designs may include features to customize seat fit and ergonomic function for individual body shapes and sizes. For example, 4-way and 8-way adjustable seats have become common in the market, and more recently, 33-way adjustable seats have been developed. Adjustable seats of these types articulate using electrical motorized actuators and air driven bladders. In some designs, pulse actuation is used for providing vibration massage functionality. The foam layers commonly used in automotive seating designs have been found suitable for accommodating such adjustability in automotive seating applications, while offering suitable IFD characteristics throughout a range of positions during adjustment. 
     However, the commonly used foam layers tend to be bulky and can occupy a significant volume in an automotive interior. In addition, the foam layers have inherent insulative characteristics which require additional design considerations in heating and cooling systems to provide a desired level of comfort to a seated occupant. Further, it can be difficult to integrate additional seating components, including heat and cooling system components, electrical components such as wire-harnesses, seat adjustment modules and other auxiliary components with the foam layers. Often, these additional components need to be installed under or around the foam layers, thereby occupying additional volume in the automotive interior. Further still, common foam materials and chemistries, such as polyurethane foam, may involve the use of regulated constituents or other materials which require special handling and/or care during manufacture. Moreover, in traditional seating designs, the polyurethane foam is typically supported by steel or other metal suspension components. However, these materials can be corrosive. 
     Accordingly, it is desirable to develop an alternative to foam automotive seating designs to address the drawbacks identified above, while retaining, or improving upon, as many benefits of the foamed seating designs as possible, such as comfort and adjustability characteristics. 
     SUMMARY 
     In one aspect, a seat assembly includes a frame, a seating base layer, a compression limiter layer, a load distribution layer, and an adjustment module. The seating base layer is arranged on the frame. The compression limiter layer is arranged adjacent to the seating base layer and comprises a wave portion forming a knee support. The load distribution layer is connected to the compression limiter layer. The adjustment module is movable between a rear position and a forward position and is configured to move the wave portion between a retracted position and an extended position. The wave portion has one or more first wave elements formed as springs and one or more second wave elements formed as springs. The first wave elements are offset from the second wave elements in a radial direction. 
     In another aspect, at least one of the first wave elements form a cup shape in the extended position and form a flat shape in the retracted position. In another aspect, the compression limiter layer further comprises a coil portion that includes a plurality of coil springs. In another aspect, the plurality of coil springs extend between the seating base layer and load distribution layer. In another aspect, the plurality of coil springs are attached to the seating base layer or the load distribution layer by a plurality of snap-fit connections. 
     In another aspect, the wave portion has a length measured along a line or curve, and the length is substantially constant in both the retracted position and the extended position. In another aspect, the first wave elements are separate, individual springs having a length that extends along a width direction and include one or more waves formed along the respective length of the first wave element. In another aspect, the first wave elements are formed as substantially linear wave springs. In another aspect, the wave portion has a curved profile in the retracted position and a linear profile in the extended position. In another aspect, a first set of trunnions connect the wave portion to the load distribution layer. In another aspect, a retainer layer is positioned between the wave portion and the adjustment module, and a second set of trunnions connect the wave portion to the retainer layer. 
     In another aspect, the first wave elements are closer to the load distribution layer than the second wave elements. In another aspect, the first wave elements and the second wave elements are configured to move or slide with respect to the other. In another aspect, a force deflection or spring rate of the first wave element may be adjusted by adjusting a wave element width, a wave element shape between a flat or cupped shape, a wave height, a wave pitch, or by a change in a number of waves that comprise the first wave element. 
     In another aspect, a seat assembly has a frame, a seating base layer, a compression limiter layer, a load distribution layer, and an adjustment module. The seating base layer is arranged on the frame. The compression limiter layer is arranged adjacent to the seating base layer. The compression limiter layer has a coiled portion and a wave portion forming a knee support. The load distribution layer is connected to the compression limiter layer. The adjustment module is movable between a rear position and a forward position and configured to move the wave portion between a retracted position and an extended position. The wave portion includes one or more first wave elements formed as springs and connected to each other by a first plurality of ribs, one or more second wave elements connected to each other by a second plurality of ribs, and a first set of trunnions that connect the wave portion to the load distribution layer. 
     In another aspect, the first wave elements are closer to the load distribution layer than the second wave elements. In another aspect, the first wave elements are separate, individual springs having a length that extend along a width direction and include one or more undulations formed along the respective length of the first wave element. 
     In another aspect, a seat assembly includes a frame, a seating base layer, a retainer layer, a compression limiter layer, a load distribution layer, and an adjustment module. The seating base layer is arranged on the frame. The compression limiter layer is arranged adjacent to the seating base layer and has a coiled portion and a wave portion forming a knee support. The load distribution layer is connected to the compression limiter layer. The adjustment module is movable between a rear position and a forward position and is configured to move the wave portion between a retracted position and an extended position. The wave portion has a first plurality of wave elements connected to each other by a first plurality of ribs, a second plurality of wave elements formed as springs and connected to each other by a second plurality of ribs, and a set of trunnions connecting the wave portion to the retainer layer. 
     In another aspect, the first wave elements are formed as springs and the second wave elements are closer to the retainer layer than the first wave elements. In another aspect, the first wave elements and the second wave elements are formed as substantially linear wave springs and a force deflection or spring rate of one or more of the second wave elements may be adjusted by adjusting a wave element width, a wave element shape between a flat or cupped shape, a wave height, a wave pitch, or by a change in the number of waves that form the second wave element. 
     These and other features and advantages of the present device will be apparent from the following description, taken in conjunction with the accompanying sheets of drawings, and in conjunction with the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       The benefits and advantages of the present embodiments will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein: 
         FIG.  1    is bottom perspective view of a seat assembly according to an embodiment described herein; 
         FIG.  2    is a top perspective view of the seat assembly of  FIG.  1   ; 
         FIG.  3    is an exploded view of the seat assembly of  FIGS.  1  and  2   ; 
         FIG.  4    is a schematic illustration of a side of a seat assembly showing the various layers of the seat; 
         FIG.  5    is an illustration of an embodiment of a wave portion showing knee support foam replacement in a retracted position around knee adjustment modules; 
         FIGS.  6 A and  6 B  illustrate an adjustment module in a rear position ( FIG.  6 A ) and in a forward position ( FIG.  6 B ) according to embodiments; 
         FIGS.  7 A and  7 B  are similar to  FIGS.  6 A and  6 B , showing embodiments of the present layered seat configuration; 
         FIGS.  8 A and  8 B  illustrate one cushion concept in a perspective view, with the load distribution layer removed for ease of illustration, and showing the compression limiter layer ( FIG.  8 A ); and a perspective view showing the load distribution layer ( FIG.  8 B ), according to embodiments; 
         FIG.  9    is a diagram showing the wave portion as tooled, in a substantially linear configuration, and as installed in the seat assembly, in a substantially curved configuration, according to an embodiment; 
         FIG.  10    is a perspective view showing the wave portion installed at a knee-support section of a seat assembly, according to an embodiment; 
         FIG.  11    is a top view showing left and right wave portions configured for independent adjustment on a seat assembly, according to an embodiment; 
         FIG.  12    is a side view of a compression limiter layer with the wave portion in a retracted position, according to an embodiment; 
         FIG.  13    is a side view of a compression limiter layer with the wave portion in a fully extended position, according to an embodiment; and 
         FIG.  14    is a perspective view of a compression limiter layer with the wave portion in a retracted position, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE 
     While the present disclosure is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described one or more embodiments with the understanding that the present disclosure is to be considered illustrative only and is not intended to limit the disclosure to any specific embodiment described or illustrated. 
       FIGS.  1  and  2    are bottom and top perspective views, respectively, of a seat assembly  10 , according to embodiments described herein. The seat assembly  10  may be constructed as a foamless seat assembly  10 .  FIG.  3    is an exploded view of the seat assembly  10  of  FIGS.  1  and  2   . According to an embodiment, the seat assembly  10  may be an automotive seat assembly designed for installation and use in automobiles. 
     With reference to  FIGS.  1 - 3   , the seat assembly  10  generally includes a seating base layer  12 , a compression limiter layer  14  and a load distribution layer  16 . In one embodiment, the seating base layer  12  may be built using an oriented or partially oriented block copolymer, such as a thermoplastic elastomer (TPE). The compression limiter layer  14 , as will be described further below, generally includes a coil portion  18  and a wave portion  20 . The load distribution layer  16  may be arranged over the compression limiter layer  14  and is configured to distribute a load, for example, from an occupant seated on the seat assembly  10 , across the compression limiter layer  14 . A retainer layer  22  may underly at least a portion of compression limiter layer  14 , for example, at the wave portion  20 . 
     The seat assembly  10  may further include a frame  24 , an adjustment module  26  and a bolster  28 . The frame  24  may be configured for connection to an automotive vehicle body or frame. The adjustment module  26  is configured to adjust a position of a seating component, as described below. The bolster  28  may be included in the seat assembly  10  to provide a variable reaction spring force that substantially mimics comfort characteristics (e.g., IFD) of traditional foam seating components, but can be formed by injection molded thermoplastics in known injection molding processes. In some embodiments, the bolster  28  may extend over rigid or angled seating components to limit occupant exposure to such components and improve comfort. In one embodiment, the seat assembly  10  may also include a manifold membrane  30 . The manifold membrane  30  may be used with, for example, heating and/or cooling systems (not shown) of the seat assembly  10 . 
       FIG.  4    is a diagram showing an exploded side view of the seat assembly  10 , with some components shown schematically, according to an embodiment. In one embodiment, the seat assembly  10  may include a trim cover  32 , such as leather or fabric, disposed over the load distribution layer  16 . In one embodiment, the seat assembly  10  may include heating and/or cooling systems, which may include, for example, a heater mat  34  disposed under the load distribution layer  16 , a vent blower  36  and a wire harness  38  which may be disposed, for instance, under the seating base layer  12  and adjacent to or within the frame  24 . However, these components are not limited to such positions. 
     According to an embodiment, the coil portion  18  of the compression limiter layer  14  generally extends along a section of the seat assembly  10  where an occupant is seated, i.e., where a substantially vertical component of an occupant&#39;s weight will be applied to the seat assembly  10 . The coil portion  18  may be formed by a plurality of coil springs extending between the seating base layer  12  and the load distribution layer  16 . The coil springs may be attached to the seating base layer  12  and/or the load distribution layer  16 , for example, by a plurality of snap-fit connections or other suitable attachment mechanisms. 
     The wave portion  20  of the compression limiter layer  14  may generally extend over a knee-support section of the seat assembly  10 , designed to support an underside or back of an occupant&#39;s knee when the occupant is in a seated position. Thus, in at least one configuration, the wave portion  20  may be extend generally in linear helical shape, around a center of curvature. For example, as shown in  FIG.  4   , in the side view, the wave portion  20  may extend as a curved segment generally in a C-shape. 
     In one embodiment, the adjustment module  26  may be a knee support module configured to adjust a position of the knee-support section of the seat assembly  10 . For example, as described further below, the adjustment module  26  may be actuated to move the wave portion  20 . In one embodiment, the adjustment module  26  includes an actuator  40  operably connected to a body  42 . The actuator  40  can be operated to drive the body  42  to adjust the position of the knee-support section. 
       FIG.  5    is an enlarged perspective view of the seat assembly  10  showing the compression limiter layer  14 , including the wave portion  20  at the knee-support section, according to an embodiment. The wave portion  20  may be substantially linear in overall shape, for example, extending a width direction ‘W’ of the seat assembly  10 . The wave portion  20  includes a plurality of wave elements  44 ,  46 . In one embodiment, the plurality of wave elements includes one or more first wave elements  44  and one or more second wave elements  46 . In one embodiment, a plurality of first and second wave elements  44 ,  46  are provided, and individual first and second wave elements  44 ,  46  are alternately positioned with respect to one another along a length direction or direction of curvature. In one embodiment, the first and second wave elements  44 ,  46  may be offset, or staggered, from one another in radial direction or thickness direction. For example, the first wave elements  44  may be relatively outwardly positioned (i.e., closer to an exterior of the seat assembly  10  or the load support layer  16 ) and the second wave elements  46  may be relative inwardly positioned (i.e., closer to the retainer layer  22  or the adjustment module  26 ). In one embodiment, the wave elements  44 ,  46  may be made from a thermoplastic material. 
     In one embodiment, the wave elements  44 ,  46  of the first and second wave elements may be formed as separate, individual springs and may include, for example, one or waves or undulations formed along their respective lengths (the lengths of the wave elements  44 ,  46  extend in the width direction W of the seat assembly  10  in  FIG.  5   ). That is, the wave elements  44 ,  46  may be formed as substantially linear wave springs. In another embodiment, the individual wave elements  44 ,  46  may include cup-shaped portions or may be substantially flat. The wave elements  44 ,  46  may be connected to one another by one or more ribs  48 . The ribs  48  are configured to flex when needed, for example, during adjustment of the knee-support section as described further below, thereby allowing movement of the first and second wave elements  44 ,  46 . 
     In one embodiment, the first wave elements  44  may be connected to the load distribution layer  16  by one or more snap-fit connections or other suitable connections. For example, the first wave elements  44  may include one or more trunnions  50  or other suitable projections configured for snap-fit engagement with an underside of the load distribution layer  16 . Similarly, the second wave elements  46  may be connected to the retainer layer  22  by one or more trunnions (not shown) or similar suitable projections configured for snap-fit engagement with the retainer layer  22 . However, the present disclosure is not limited to such snap-fit engagements, and other suitable connections are envisioned. 
       FIGS.  6 A and  6 B  are side views of the seat assembly  10  with the adjustment module  26  in a rear (or retracted) position ( FIG.  6 A ) and a forward (or extended) position ( FIG.  6 B ), according to embodiments of the present disclosure. As shown in  FIGS.  6 A and  6 B , to adjust a position of the knee-support section of the seat assembly  10 , the actuator  40  is operated to move the body  42  outward from the position in  FIG.  6 A  to the position in  FIG.  6 B  to extend a length of the knee-support section. Conversely, the actuator  40  may be operated to move the body  42  inward from the position in  FIG.  6 B  to the position in  FIG.  6 A  to reduce a length of the knee-support section. 
       FIGS.  7 A and  7 B  are side views of the seat assembly  10  having the retainer  22  and compression limiter layer  14 , including the wave portion  20 , positioned over the adjustment module  26  (see  FIGS.  6 A,  6 B ), with the adjustment module  26  in the rear (retracted) position ( FIG.  7 A ) and the forward (extended) position ( FIG.  7 B ), according to embodiments of the present disclosure. The wave portion  20 , including the first and second wave elements  44 ,  46  (see  FIG.  5   ), is configured such that movement of the adjustment module  26  from the rear position to forward position, and vice versa, causes the wave portion  20  to slide along a surface of the body  42  without binding, wrinkling or loosing desired or customer-specified IFD requirements. Therefore, the compression limiter layer  14 , by way of the wave portion  20  of the embodiments described herein, can provide consistent comfort in all positions of adjustment module  26 . The retainer layer  22  is configured for sliding movement relative to a surface of the body  42  with the wave portion  20 . 
     The sliding movement of the wave portion  20  is provided by the arrangement of the first and second wave elements  44 ,  46 , which are provided separately from one another, and are configured to move independently of one another. Thus, during sliding movement of the wave portion  20 , individual first and second elements  44 ,  46  may be move relative to one another. 
     Referring still to  FIGS.  7 A and  7 B , the wave portion  20  is in a retracted position when the adjustment module  26  is in the rear position ( FIG.  7 A ). In the retracted position, the wave portion  20  has a substantially curved profile in the side view. Movement of the adjustment module  26  to the forward position moves the wave portion  20  to an extended position ( FIG.  7 B ). In the extended position, according to one embodiment, the wave portion  20  is at least partially straightened, i.e., moved toward a linear profile from the curved profile, in the side view. As a result of the sliding movement of the wave portion  20  relative to the body  42 , a free end  52  of the wave portion  20  changes position relative to a surface of the body  42 . Conversely, movement of the adjustment module  26  from the forward position to the rear position causes movement of the wave portion  20  from the extended position to the retracted position. In addition, wave shape and load displacement can be maintained throughout adjustment. 
       FIGS.  8 A and  8 B  are perspective views showing the seat assembly  10  with the load distribution layer  16  removed, to more clearly illustrate the compression limiter layer  14  (FIG. SA) and with the load distribution layer  16  installed ( FIG.  8 B ), according to embodiments described herein. In one embodiment, the load distribution layer  16  includes a plurality of shaped segments  54  connected to another. In one embodiment, each segment  54  may be connected to the compression limiter layer  14 , for example, by a snap-fit connection. In this manner, pressure applied to the load distribution layer  16  may be distributed across the segments  54  and the compression limiter layer  14  to obtain desirable IFD characteristics and pressure maps. 
       FIG.  9    is a diagram showing the wave portion  20  as tooled, in a substantially linear configuration, and as installed on the seat assembly  10 , in a substantially curved configuration, similar to the retracted position described in the embodiments above. As shown in  FIG.  9   , in one embodiment, a thickness of the second wave elements  46  may gradually decrease moving toward the free end  52  of the wave portion  20 . 
       FIG.  10    is a perspective view showing the wave portion  20  installed at a knee-support section of a seat assembly  10 , according to an embodiment. 
       FIG.  11    is a top view showing left and right wave portions  20 L,  20 R configured for independent adjustment on a seat assembly  10 , according to an embodiment. In one embodiment, the seat assembly  10  may include independently adjustable left and right knee-support sections. To this end, separate left and right wave portions  20 L,  20 R may be provided. Although not shown in  FIG.  11   , it is understood that separate left and right adjustment modules  26  can be provided as well and can be operated independently of each other. 
       FIG.  12    is a side view of the compression limiter layer  14  with the wave portion  20  in the retracted position and  FIG.  13    is a side view of the compression limiter layer  14  with the wave portion  20  in a fully extended position, according to embodiments described herein. As described above, and shown in  FIG.  12   , in the retracted position, the wave portion  20  may have a substantially curved profile in the side view and may be shaped as a linear helix. In a fully extended position, as shown in  FIG.  13   , the wave portion  20  may be arranged in a substantially linear or planar configuration. The wave elements  44 ,  46  are configured for movement during adjustment such that stretching or pinching of a trim cover  32  is substantially limited or prevented while the wave elements  44 ,  46  provide a cushioning effect and desirable IFD compliance throughout the adjustment. In one embodiment, a length  1 ′ of the wave portion  20 , measured along a line or a curve, may be substantially constant during movement of the wave portion  20  between the retracted and extended positions because of the sliding motion of the wave elements  44 ,  46 . In one embodiment, this feature may be accommodated, at least in part, by independent relative movement of the individual wave elements  44 ,  46  during adjustment. 
       FIG.  14    is a perspective view of the compression limiter layer  14  with the wave portion  20  in the retracted position, according to an embodiment. As described in the embodiments above, the first and second wave elements  44 ,  46  may be alternately positioned relative to one another and offset or staggered. 
     In the embodiments above, the design of the wave portion  20  maintains a common length of line at a class A interface where the trim cover  32  contacts the load distribution layer  16 . The length of line design rule enables the wave portion to fold and expand (i.e., retract and extend) during adjustment without wrinkling or overstretching the trim cover  32 . The length of line positioning also enables manufacturers to remove and replace trim covers  32 , and/or use the load distribution layer  16  is an occupant interface. 
     The seat assembly  10  of the embodiments described herein, in which conventional foam layers are replaced with the compression limiter layer  14  including the wave portion  20 , may allow for seats to be produced at reduced costs, occupy a smaller volume, provide more breathable occupant seating interfaces, avoid absorption of fluids, be easily cleaned and can reduce emissions by using inert thermoplastic materials. 
     The embodiments described herein, including the compression limiter layer  14  having the wave portion  20 , may also permit varying the thickness and profile shape of the seat throughout seating adjustment. Seating shapes utilizing suspension tension members have traditionally been limited to one-dimensional (ID) variable profiles by altering the tension frame shape. However, two-dimensional (2D) seat surface profiles have been limited when using suspension only. Materials that offer compression limiter function and physical thickness like foams or coils springs can offer 2D profiles to seat stylists, but are limited when wrapping around actuated radiuses, such as at knee-support sections. As illustrated in  FIGS.  5 ,  6 A,  6 B,  7 A and  7 B , wave portion  20  described herein allows several millimeters of actuator travel while maintaining seat shape, and IFD compliance for comfort. 
     The wave portion  20  is also adaptable to different customer requirements through a wide range of tuning mechanisms. For example, force deflection or spring rate may be tuned by adjusting wave element width, wave element shape (flat vs. cupped), wave element material, modulus performance, top (outer) wave vs. bottom (inner) wave height and wave pitch and sign wave frequency (number of waves), and other inputs. 
     It has been found that the embodiments of the seat assembly  10  described herein are capable of providing an IFD compliant design that mimics or outperforms foam materials used in conventional automotive seating applications during most or all adjustment positions. The adjustments highlighted in  FIGS.  6 A- 6 B and  7 A- 7 B  show an example of a range of actuated adjustment (for example, a 50 mm-100 mm range) for occupant positioning within a 33-way adjustable seat. 
     It should also be understood that various changes and modifications to the presently disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims. It is further understood that various features from the embodiments described above and shown in the drawings may be combined with other embodiments described herein and shown in the drawings.