Patent Publication Number: US-8991921-B2

Title: Seating unit with seat position and depth adjustment assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a seating unit having a position- and depth-adjustable seat. In particular, the present invention relates to a seating unit including a seat assembly which is expandable between a first configuration and a second configuration and translatable between a first position and a second position. 
     Today, persons engage in a variety of sedentary activities which involve prolonged periods of sitting, such as watching television, working in an office and traveling. There are also those with physical disabilities who are confined to a wheelchair. In a seated position, a majority of a user&#39;s weight is transferred primarily to the ischial tuberosities (“sitting bones”) of the pelvis and their surrounding soft tissues. Weight is also transferred to the thighs. Regardless of the sedentary activity, prolonged sitting without proper support can cause discomfort to the lower body and back. A seating unit having adjustable seat depth and position can help alleviate this discomfort. 
     Modern consumers demand a wide variety of seating options and features, including an adjustable support which allows for major differences in the shape and size of users. Known seating units provide mechanisms for adjusting the seat position to support the ischial tuberosities and adjusting the seat depth to support the thighs. However, these seating units utilize separate adjustment mechanisms and user controls. Also, translation and expansion movements of the seat are not coordinated to provide a smooth and easy seat adjustment. Further, it is important that the options and features are incorporated into the seating unit construction such that manufacturing and assembly efficiency and ease of user adjustability are maximized, while at the same time having an aesthetically pleasing design. 
     Accordingly, a seating unit construction solving the aforementioned problems is desired. 
     BRIEF SUMMARY OF THE INVENTION 
     In one embodiment of the present invention, a seating unit includes a seat assembly and an adjustment assembly coupled to the seat assembly. The adjustment assembly includes a single drive mechanism for translating the seat assembly from a first position to a second position and expanding the seat assembly from a first configuration to a second configuration. 
     In another embodiment of the present invention, a seating unit includes an adjustment assembly operably coupled to a seat assembly. The adjustment assembly includes a drive mechanism for translating the seat assembly from a first position to a second position and expanding the seat assembly from a first configuration to a second configuration. The seat assembly includes a cushion assembly having a forward portion with two or more cutouts and a leading edge. The two or more cutouts are in a compressed state when the seat assembly is in the first configuration relative to the second configuration. 
     In yet another embodiment of the present invention, a seating unit includes a drive mechanism operably coupled to a seat assembly. The drive mechanism translates the seat assembly from a first position to a second position and expands the seat assembly from a first configuration to a second configuration. The seat assembly includes a cushion assembly having two or more nested cushion portions. The two or more nested cushion portions are separated when the seat assembly moves from the first configuration to the second configuration. 
     In another embodiment of the present invention, a seating assembly includes a seat support structure, a seat support pan, a seat extension member and a drive mechanism. The drive mechanism includes a housing having a threaded portion, a first drive screw threadably received within the housing threaded portion, a seat drive member including a body portion having a threaded portion which threadably engages a second drive screw and a plurality of guide legs which engage and track along sides of the housing, and an extension drive member positioned between the first drive screw and the second drive screw. The housing is secured to the seat support structure, the seat drive member is secured to the seat support pan, and the extension drive member is secured to the seat extension member. 
     These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other items and advantages of the present invention will be appreciated more fully from the following figures, where like reference characters designate like features in which: 
         FIG. 1  is a perspective view of a seating unit including a depth and position-adjustable seat having a comfort surface; 
         FIG. 2  is a perspective view of the seating unit of  FIG. 1  with the comfort surface removed from the seat; 
         FIG. 3  is a right side view of the seating unit of  FIG. 1  including a cross-sectional view of the depth and position-adjustable seat; 
         FIG. 4  is a perspective view of a first embodiment of a cushion; 
         FIG. 5  is a top view of the cushion of  FIG. 4  including a fragmentary view of a cutout; 
         FIG. 6  is a cross-sectional view of the cushion of  FIG. 4 ; 
         FIG. 7  is a top view of a second embodiment of a cushion; 
         FIG. 8  is a top view of a third embodiment of a cushion; 
         FIG. 9  is a perspective view of an adjustment assembly shown in a first position; 
         FIG. 10  is a top perspective view of a housing of the adjustment assembly of  FIG. 9 ; 
         FIG. 11  is a top perspective view of a seat drive member of the adjustment assembly of  FIG. 9 ; 
         FIG. 12  is a bottom view of the seat drive member of  FIG. 11 ; 
         FIG. 13  is a cross-sectional view of the depth and position-adjustable seat, shown in a first position; and 
         FIG. 14  is a cross-sectional view of the depth and position-adjustable seat, shown in a second position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of description herein, the terms “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to a seating unit as oriented in  FIG. 1 . However, it is to be understood that the seating unit may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described below are simply exemplary embodiments of the invented concepts. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting. 
     A seating unit  10  includes a seat assembly  12 , a back assembly  14 , a support assembly  16  and an adjustment assembly  18 . The seating unit may also include arm assemblies (not shown).  FIGS. 1-3  illustrate one embodiment of the seating unit  10 , namely an office chair. However, it is contemplated that the scope of the present invention includes any seating unit having a seat assembly, a back assembly and a support assembly, including, but not limited to, a chair, a motor vehicle seat, an airplane seat, and a wheelchair. Accordingly, the present invention is not intended to be unnecessarily limited and the term “seating unit” as used herein is intended to be broadly construed. 
     The seat assembly  12  includes a seat support pan  20  covered by a cushion assembly  22  having a comfort surface  24 , or by a comfort surface  24  alone. A front edge of the comfort surface  24  or cushion assembly  22  defines a leading edge  26  of the seat assembly  12 . Typically, the seat assembly  12  support pan  20  is covered by a cushion assembly  22  including the comfort surface  24  supported by a cushion  28 . Likewise, the back assembly  14  includes a back shell covered by a comfort surface or a back cushion assembly, where the back cushion assembly includes a back cushion covered by the comfort surface. The cushion assembly  22  covering the seat assembly  12  may be separate from the cushion assembly covering the back assembly  14  or combined. The seat assembly  12  also includes a seat extension member  29 . The seat assembly may further include a seat support structure  30  supported by the support assembly  16 . The seat extension member  29  is expandable in a direction  32  between a first configuration A and a second configuration B and the support pan  20  is translatable in direction  34  between a first position and a second position. 
     The comfort surface  24  includes a resilient fabric and the cushion  28  includes a foamed elastomeric compound. Suitable foamed elastomeric compounds include, but are not limited to, polyethylene, latex, and polyurethane foams, and combinations thereof. In a first illustrated example ( FIGS. 4-6 ), the cushion  28  includes a plurality of cutouts extending therethrough. In particular, the cushion  28  includes circularly-shaped cutouts  36  and elongated cutouts  38 . As best illustrated in  FIGS. 5 and 6 , each cutout  36 ,  38  includes a molded upper portion  40  and a die cut lower portion  42 . The upper portion  40  is molded into an upper surface  44  of the cushion  28  as the cushion  28  is formed, and includes radiused or rounded edges which define the location for each of the cutouts  36 ,  38 . The lower portion  42  of each of the cutouts  36 ,  38  is then die cut such that the overall cutout  36 ,  38  extends through the entire depth of the cushion  28 . The forming of the cutouts  36 ,  38  within the cushion  28  adjusts the spring rate of the cushion  28  in the vicinity of the cutouts  36 ,  38 . The forming of the rounded upper portion of each of the cutouts  36 ,  38  provides added comfort to the seated user, as well as improves the aesthetic appearance of the seat assembly  12  when the comfort surface  24  is tightly stretched over the seat assembly  12 . 
     Referring to  FIG. 5 , either cutouts  36 ,  38  may be replaced by cutouts  46  having variable cross-sectional configurations. Each cutout  46  includes an elongated or football-shaped upper portion  48  and a circularly-shaped lower portion  50 . The overall cutout  46  extends through the entire depth of the cushion  28 . By combining the elongated upper portion  48  with the circularly-shaped lower portion  50 , the overall spring rate as provided by the cushion  28  is similar to that as provided by cutouts  36 , while the aesthetic appearance is similar to that as provided by cutouts  38 . 
     Still referring to  FIG. 5 , the cutouts  36 ,  38  are selectively spaced about the cushion  28 . The spring rate of the cushion  28  in any particular location may be adjusted by adjusting the relative spacing of the cutouts  36 ,  38  from one another and from the edges of the cushion  28 . Further, spacing of the cutouts allows adjustment of the spring rate to compensate for various foam thicknesses, as the cushion  28  can vary in thickness across a width W and length L thereof. The spring rate in any particular area of the cushion  28  in both a vertical and horizontal direction may be adjusted by changing the orientation of the cutouts. As exemplified in area C, the orientation of cutouts  38  have been adjusted such that the cutouts  38  extend somewhat parallel with the outer edges of the cushion  28 . 
     Alternatively, instead of cutouts  36 ,  38 , the cushion  28  may include two or more nested portions  52 , where a nested portion is positioned adjacent to at least one other nested portion. The configuration of the nested portions  52  can vary. For example, as illustrated in  FIG. 7 , each nested portion  52  includes cutouts  54  connected by linking structures  56 , with a cutout  54  of one nested portion  52  juxtaposed to the linking structure  56  of another nested portion. Although cutouts  54  include a hexagonal structure is shown in  FIG. 7 , any regular or irregular polygonal shape is suitable.  FIG. 8  illustrates another example of a cushion  28  including nesting portions  52  having an undulating wave shape  58 . 
     Referring now to  FIGS. 9-13 , the adjustment assembly  18  is a single drive mechanism and includes a housing  60  having a threaded portion  62  and a guide portion  64 , a first drive screw  66  threadably received within the threaded portion  62 , a second drive screw  68  located within the guide portion  64  and threadably receiving a seat drive member  70  thereon, and an extension drive member  72  positioned between the first drive screw  66  and the second drive screw  68 . The seat drive member  70  includes a body portion  74  and a plurality of guide legs  76  that engage and track along sides of the housing  60 . The body portion  74  of the seat drive member  70  includes a threaded portion  78  that threadably engages the second drive screw  68 . The adjustment assembly  18  is operably attached to the seat assembly  12  with the housing  60  fixedly secured to the seat support structure  30 , the seat drive member  70  fixedly secured to the seat support pan  20 , and the extension drive member  72  fixedly secured to the seat extension member  29 . 
     In operation, a user can translate and expand the seat assembly  12  by adjusting a single control mechanism. In particular, as illustrated in  FIGS. 9 ,  13  and  14 , a rotational input from the user rotates an input device, such as control handle  80 , in a direction  82 , thereby rotating the first drive screw  66  and the second drive screw  68  and moving the seat drive member  70  and seat support pan  20  from a first position D to a second position E and expanding the extension drive member  72  and seat extension member  29  from a first position F to a second position G. Translation and expansion are coordinated and occur such that the relative position of the leading edge  26  of the seat assembly  12  can be adjusted between a fully retracted position and configuration, where the seat extension member  29  is in the first configuration A and the support pan  20  is in the first position, and a fully extended position and configuration, where the seat extension member  29  is in the second configuration B and the support pan is in the second position. Typically, coordinated translation and expansion movements occur simultaneously, but movements may also occur alternately. Where movements are simultaneous, translation of the seat support pan  20  and expansion of the seat extension member  29  may occur synchronously or at different rates. The thread ratio between the first drive screw  66  and the second drive screw  68  may be adjusted to adjust the overall ratio between which the position of the seat assembly and the overall depth of the seat assembly are adjusted. 
     As the seat extension member  29  expands from the first configuration A to the second configuration B, the length L of the cushion assembly  22  increases. In the first configuration A, the leading edge  26  is substantially linear, but seat assembly  12  may include radiused or rounded corners to form a slightly convex leading edge. In one embodiment, as the seat assembly  12  moves from the first configuration A to the second configuration B, the leading edge  26  becomes more convex. In another embodiment, as the seat assembly  12  moves from the first configuration A to the second configuration B, the leading edge  26  remains substantially linear. 
     In the first configuration A, cushion  28  is in a compressed state such that voids formed by cutouts  36 ,  38 ,  54  or gaps  84  between nesting portions  52  are minimized. As a cushion  28  having cutouts  36 ,  38  or cutouts  54  expands from the first configuration A to the second configuration B, the size of the voids increase and the cushion progresses from the compressed state to a less compressed state. As a cushion  28  including nested portions  52  expands from the first configuration A to the second configuration B, the nested portions separate from each other, thereby increasing gaps  84  between adjacent nested portions. 
     In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.