Patent Publication Number: US-2023148754-A1

Title: Seating arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Pat Application No. 17/031,180, filed on Sep. 24, 2020, entitled “SEATING ARRANGEMENT,” which is a continuation of U.S. Pat. Application No. 16/590,523, filed on Oct. 2, 2019, entitled “SEATING ARRANGEMENT,” now U.S. Patent No. 10,813,459, which is a divisional of U.S. Pat. Application No. 15/605,760, filed on May 25, 2017, entitled “SEATING ARRANGEMENT,” now U.S. Pat. No. 10,463,153, which claims the benefit of U.S. Provisional Pat. Application No. 62/347,930, filed on Jun. 9, 2016, entitled, “SEATING ARRANGEMENT,” and U.S. Provisional Pat. Application No. 62/447,169, filed on Jan. 17, 2017, entitled, “SEATING ARRANGEMENT,” the entire disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     Various embodiments relate to a seating arrangement that includes various combinations of linearly adjustable seat assemblies, reclinable back assemblies, flexible back support assemblies, control arrangements and vertically adjustable arm assemblies. 
     BRIEF SUMMARY 
     In one embodiment as shown and described, a seating arrangement may include a seat assembly slidably movable between a forward most position and a rearward most position, the seat assembly including a seat support structure configured to support a seated user thereon, and at least one elongated slide bearing attached to the seat support structure and including a bearing surface and at least one stop member, wherein the bearing surface and the at least one stop member are a single, integral piece, and at least one slide support member that slidably supports the slide bearing thereon between the forward most position and the rearward most position, wherein the at least one stop member is configured to prevent the seat assembly from being moved beyond at least one of the forward most position and the rearward most position. 
     Another embodiment as shown and described may further or alternatively include a seating arrangement that includes a seat assembly slidably movable between a forward most position and a rearward most position, including a seat support structure configured to support a seated user thereon, wherein the seat support structure is flexibly resilient, and at least one elongated slide bearing attached to the seat support structure thereby structurally reinforcing the seat support structure from flexure, wherein the at least one slide bearing includes a bearing surface and at least one stop member, and at least one slide support member that slidably supports the slide bearing thereon between the forward most position and the rearward most position, wherein the at least one stop member is configured to prevent the seat assembly from being moved beyond at least one of the forward most position and the rearward most position. 
     Yet another embodiment as shown and described may further or alternatively include a seating arrangement that includes a seat assembly slidably movable between a forward most position and a rearward most position, including a seat support structure configured to support a seated user thereon, at least one elongated slide bearing attached to the seat support structure, wherein the at least one slide bearing includes a bearing surface and at least one stop member, and wherein the at least one stop member is configured to prevent the seat assembly from being moved beyond at least one of the forward most position and the rearward most position, and a release portion operably coupled to the at least one stop member and configured to move the at least one stop member from the first position to the second position, wherein the release portion is accessible from an exterior of the seating arrangement without use of a tool, and at least one slide support member that slidably supports the slide bearing thereon between the forward most position and the rearward most position. 
     These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an embodiment of a seating arrangement; 
         FIG.  2    is a side elevational view of the embodiment of the seating arrangement, wherein the seating arrangement is shown in a lowered position and a raised position, and in an upright position and a reclined position, and a seat assembly is shown in a retracted position and an extended position; 
         FIG.  3    is an exploded view of the seat assembly; 
         FIG.  4    is a cross-sectional view of a coupling arrangement between an upper shell member and a lower shell member of the seat assembly; 
         FIG.  5    is a top perspective view of a slide bearing member; 
         FIG.  6    is a bottom perspective view of the slide bearing member; 
         FIG.  7    is a cross-sectional view of the seat assembly taken along the line VII-VII,  FIG.  1   ; 
         FIG.  8    is a perspective view of the seat assembly with a cover, a cushion member and the top shell member removed to expose an interior of the seat assembly; 
         FIG.  9    is an exploded view of a back assembly; 
         FIG.  9 A  is a perspective view of a flush-mount fastener; 
         FIG.  10    is a rear perspective view of a back shell member; 
         FIG.  11 A  is an exploded perspective view of a lumbar support assembly; 
         FIG.  11 B 1    is a perspective view of a mounting member of the lumbar support assembly; 
         FIG.  11 B 2    is a second perspective view of the mounting member of the lumbar support assembly; 
         FIG.  11 C  is a perspective view of an alternative embodiment of the lumbar support assembly; 
         FIG.  11 D  is a top plan view of the alternative embodiment of the lumbar support assembly; 
         FIG.  11 E  is an exploded perspective view of the alternative embodiment of the lumbar support assembly; 
         FIG.  11 F  is a cross-sectional side elevational view of the backrest assembly illustrating an S-point as defined by the lumbar support assembly; 
         FIG.  12    is a cross-sectional side elevational view of the back assembly; 
         FIG.  13    is a cross-sectional view of a connection arrangement between the lumbar assembly, a back frame member and the back shell member taken along the line XIII-XIII,  FIG.  1   ; 
         FIG.  14 A  is a side elevational view of a four-bar linkage arrangement of the seating arrangement shown in an upright position with interior components shown in dashed line; 
         FIG.  14 B  is a side elevational view of the four-bar linkage arrangement of the seating assembly shown in a reclined position with interior components shown in dashed line; 
         FIG.  15 A  is a perspective view of a quick connect arrangement taken of the area XVA,  FIG.  9   ; 
         FIG.  15 B  is a front elevational view of the quick connection arrangement; 
         FIG.  15 C  is a side elevational cross-sectional view of the quick connect coupling arrangement taken along the line XVC-XVC,  FIG.  15 B ; 
         FIG.  16 A  is a front perspective view of a locking arrangement for the quick connect coupling arrangement; 
         FIG.  16 B  is a rear perspective view of the locking arrangement; 
         FIG.  16 C  is a side elevational view of the locking arrangement; 
         FIG.  16 D  is a perspective view of a primary locking portion of the locking arrangement; 
         FIGS.  17 - 19    are cross-sectional side elevational views of the quick connect arrangement shown in various states of coupling the back assembly to a control assembly of the seating arrangement; 
         FIG.  20    is a top perspective view of a primary biasing arrangement; 
         FIG.  21    is a top perspective view of an alternative configuration for the primary biasing arrangement; 
         FIG.  22    is a top perspective view of an auxiliary biasing arrangement; 
         FIG.  23 A  is a cross-sectional side elevational view of the auxiliary biasing arrangement of  FIG.  22    shown in a neutral position; 
         FIG.  23 B  is a cross-sectional side elevational view of the auxiliary biasing arrangement of  FIG.  22    shown in a biasing position; 
         FIG.  23 C  is a cross-sectional side elevational view of the auxiliary biasing arrangement for  FIG.  22    shown in a locked position; 
         FIG.  24    is a perspective view of the control arrangement of  FIG.  22    showing a drive gear and a driven gear thereof; 
         FIG.  25    is a top perspective view of an alternative embodiment of an auxiliary biasing arrangement; 
         FIG.  26    is a top plan view of the auxiliary biasing arrangement of  FIG.  25   ; 
         FIG.  27    is a perspective view of another alternative embodiment of the auxiliary biasing arrangement; 
         FIG.  28    is a top plan view of the auxiliary biasing arrangement of  FIG.  27   ; 
         FIG.  29    is a cross-sectional side elevational view of a control assembly associated with the auxiliary biasing arrangement of  FIG.  27   ; 
         FIG.  30    is a top perspective view of a vertical height control adjustment arrangement; 
         FIG.  31    is a cross-sectional side elevational view of the adjustment arrangement as shown in  FIG.  30   ; 
         FIG.  32    is an exploded view of an arm assembly; 
         FIG.  33    is a top plan view of the seating arrangement showing the arm caps of the arm assemblies of the seating arrangement in various configurations and positions; 
         FIG.  34    is a side elevational view of the arm cap and a control assembly of the arm assembly shown in  FIG.  32   ; 
         FIG.  35    is a cross-sectional perspective view of a receiver portion of the back frame member taken along the line XXXV-XXXV,  FIG.  32   ; 
         FIG.  36    is a side elevational view of an alternative embodiment of the arm assembly; 
         FIG.  37    is a side elevational view of a control arrangement for the arm assembly of  FIG.  36   ; 
         FIG.  38    is an end view of an end cap of the arm assembly of  FIG.  36   ; 
         FIG.  39    is a top perspective view of an alternative embodiment of the seating arrangement including a headrest assembly and a garment hanger; 
         FIG.  40    is an exploded view of the backrest assembly, the headrest assembly and the garment hanger of  FIG.  39   ; 
         FIG.  41    is a cross-sectional view of a coupling arrangement securing the back shell, the back frame member and the headrest assembly with one another; 
         FIG.  42    is a top perspective view of a chair assembly; 
         FIG.  43    is a bottom perspective view of the chair assembly; 
         FIG.  44    is a front elevational view of the chair assembly of  FIG.  42   ; 
         FIG.  45    is a first side elevational view of the chair assembly of  FIG.  42   ; 
         FIG.  46    is a rear elevational view of the chair assembly of  FIG.  42   ; 
         FIG.  47    is a second side elevational view of the chair assembly of  FIG.  42   ; 
         FIG.  48    is a top plan view of the chair assembly of  FIG.  42   ; and 
         FIG.  49    is a bottom plan view of the chair assembly of  FIG.  42   . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIG.  1   . However, it is to be understood that the embodiments as described herein may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are exemplary embodiments of concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Various elements of the embodiments disclosed herein may be described as being operably coupled to one another, which includes elements either directly or indirectly coupled to one another. Further, the term “seating arrangement” as utilized herein encompasses numerous seating arrangements, including, but not limited to, office chairs, vehicle seating, home seating, stadium seating, theater seating, and the like 
     The reference numeral  10  ( FIG.  1   ) generally designates a seating arrangement embodying the present invention. In the illustrated example, the seating arrangement  10  includes an office chair assembly. The seating arrangement  10  includes a castered base assembly  12  abutting a supporting floor surface  14 , a control or support assembly  16  supported by the castered base assembly  12 , a seat assembly  18 , a back assembly  20 , and a pair of arm assemblies  22 . The seating arrangement  10  ( FIG.  2   ) is configured such that the seat assembly is movable between a fully rearward position A and a fully forward position B, the back assembly  20  is movable between a fully upright position C and a fully reclined position D while the seat is movable between a fully upright position E and a fully reclined position F, and the control assembly  16 , the seat assembly  18 , the back assembly  20  and the arm assemblies  22  are movable between a fully lowered position G and a fully raised position H, as described below. The control assembly  16 , the seat assembly  18 , the back assembly  20  and the arm assemblies  22  are further rotatably supported above the base assembly  12  for pivoting about an axis  24  in the directions  26 . 
     The seat assembly  18  ( FIGS.  1  and  3   ) includes a shell assembly  28 , a contoured, molded foam cushion member  30 , and a fabric cover  32  covering the cushion member  30  and edges of the shell assembly  28 . The shell assembly  28  includes a lower shell member  34  and an upper shell member  36 . In the illustrated example, the lower shell member  34  and the upper shell member  36  are each constructed of a flexibly resilient plastic. The upper shell member  36  ( FIGS.  3  and  4   ) is connected to the lower shell member  34  by a plurality of snap coupling arrangements  37  that include a plurality of first coupling portions  38  located about a periphery of and extending upwardly from an upper surface  40  of the lower shell member  34 , and a plurality of second coupling portions  42  located about a periphery of and extending upwardly from a bottom surface  44  of the upper shell member  36 . As illustrated, the first coupling portions may include a hook-like arrangement, while the second coupling portions  42  may include a tab arrangement, wherein the second coupling portions  42  are configured to be slidably received within the first coupling portions  38  in a direction  46 . The upper shell member  36  is then further secured to the lower shell member  34  by a plurality of mechanical fasteners, such as screws (not shown) that prevents the second coupling portions  42  from disengaging the first coupling portions  38 . 
     The seating assembly  18  further includes a pair of slide bearing members  48  ( FIGS.  3 ,  5  and  6   ) configured to slidably support the seat assembly  18  on the control assembly  16 . In the illustrated example, each elongate bearing member  48  includes a first end  50 , a second end  52  and a downwardly-facing bearing surface  54  extending therebetween. Each bearing member  48  further includes a first stop member  56  located proximate the first end  50 , and a second stop member  58  located proximate the second end  52 . The first stop member  56  includes a downwardly extending abutment surface  57 , while the second stop member  58  includes a downwardly-extending, flexibly resilient tab  60  having a vertically extending abutment surface  62 . The tab  60  is located along a flexible arm  64  and is movable between a lowered or non-flexed position, wherein the abutment surface  62  extends below the bearing surface  54 , and a raised or flexed position, wherein the abutment surface  62  is positioned above the bearing surface  54 . Each bearing member  48  further includes an actuator portion  66  integrally formed with the arm  64  at a distal end, such that movement of the actuator portion  66  in a vertical direction also moves the abutment surface  62  between the lowered position and the raised position thereof. In assembly, the bearing members  48  are assembled with the lower shell member  34  of the shell assembly  28  such that the actuator portion  66  extends through a corresponding aperture  68  of the lower shell member  34 , and such that the actuator portion  66  is accessible to a user from an exterior of the seat assembly  18 . Each bearing member  48  further includes a longitudinally extending channel  70  that extends along an edge of the bearing surface  54 , and is configured to slidably couple the seat assembly  18  to the control assembly  16 , as described below. 
     As best illustrated in  FIGS.  7  and  8   , the control assembly  16  includes a housing member  72  that is fixed for movement with respect to ground, and a pair of elongated, L-shaped slide support rails  74  secured to the housing  72  via a plurality of mechanical fasteners such as screws (not shown). In the illustrated example, each slide support rail  74  includes an upwardly disposed bearing support surface  76  configured to slidably support the bearing surface  54  of one of the slide bearing members  48 . In assembly, the seat assembly  18  is slidably coupled to the control assembly  16  for longitudinal movement between the forward most position A ( FIG.  2   ) and the rearward most position B by slidably inserting the slide support rails  74  into the channels  70  of the slide bearing members  48 . As the slide bearing members  48  begin to couple with the slide support rails  74 , the tab  60  abuts a forward edge  78  of the slide support rail  74  deflecting the tabs  60  from the lowered position to the raised position thereof. The tabs  60  then slide along the bearing support surface of the slide support rail as the seat assembly  18  is moved in a rearward direction with respect to the control assembly  16 , until the tabs  60  reach a rearward edge  80  of the slide support rail  74  and the tabs  60  snap downwardly from the raised position to the lowered position thereof. In use, the rearward longitudinal travel of the seat assembly  18  with respect to the control assembly  16  is limited by abutment of the abutment surface  57  with the forward edge  78  of the slide support rail  74 , while the forward longitudinal travel of the seat assembly  18  with respect to the control assembly  16  is limited by abutment of the abutment surface  62  of the tabs  60  with the rearward edge  80  of the slide support rail  74 . The seat assembly  18  may be removed from attachment with the control assembly  16  by exerting an upwardly directed force on the actuator portion  66  of each of the slide bearing members  48  moving the abutment surfaces  62  from the lowered position to the raised position, thereby allowing the abutment surfaces  62  to clear the rearward edge  80  of the slide support rails  64  as the seat assembly  18  is moved from the rearward most position A toward the forward most position B. It is noted that the actuator portion  66  is accessible from an exterior of the seat assembly  16  and may be actuated without the use of a separate tool. 
     The seat assembly  18  and the control assembly  16  are further configured to allow the user to lock the seat assembly  18  at a predetermined position between the rearward most position A ( FIG.  2   ) and the forward most position B. As shown in  FIG.  8   , the seat assembly  18  further includes a locking arrangement  82  that includes a locking member  84  slidably disposed within the shell assembly  28 . In the illustrated example, the locking member  84  includes a planar body portion  86  sandwiched between the lower shell member  34  and the upper shell member  36  ( FIG.  7   ), and slidable between an engaged position Y, and a disengaged position Z. A pair of teeth  88  extending laterally inward from the body portion  86  and are configured to selectively engage two of a plurality of recesses  90  spaced longitudinally along one of the slide support rails  74 . A handle portion  92  extends downwardly from the body portion  86  and through an aperture  94  within the lower shell member  34 . The handle portion  92  is configured to be easily grasped by a user so that the user can move the locking member  84  between the locked position Y and the unlocked position Z. A coil spring  96  biases the locking member  84  from the unlocked position Z toward the locked position Y. In operation, a user may grasp the handle portion  92  and move the handle portion  92  in a direction  98  thereby overcoming the biasing force exerted on the locking portion  84  by the coil spring  96  and disengaging the pair of teeth  88  of the locking member  84  from the recesses  90  of the slide support rail  74 , thereby allowing the seat assembly  18  to be longitudinally adjusted with respect to the control assembly  18  between the rearward most position A and the forward most position B. Once a selected position has been reached, the operator releases the force being exerted onto the handle portion  92 , thereby allowing the spring  96  to bias the teeth  88  of the locking member  84  into engagement with the apertures  90  with which the teeth  88  are aligned, thereby preventing further sliding movement of the seat assembly  18  with respect to the control assembly  16 . In an alternative embodiment, the seat assembly  18  may only be removed from attachment with the control assembly  16  by exerting an upwardly directed force on the actuator portion  66  of both of the slide bearings  48 , while simultaneously moving the handle portion  92  of the locking arrangement  82  and disengaging the teeth  88  from the recesses  90  of the slide support rail  74 . This configuration requires three separate inputs to the seat assembly  18  and control assembly  16  to detach the seat assembly  18  from the control assembly  16 . It is noted that the actuator portion  66  and the handle portion  92  are sufficiently spaced from one another that it is difficult for a single operator to move all three portions without specific effort to do so. 
     The back assembly  20  ( FIGS.  1  and  9   ) includes a substantially rigid back frame member  102 , a flexibly resilient back shell member  104 , a lumbar support assembly  106  slidably positioned between the back frame member  102  and the back shell member  104 , and a fabric cover  108  covering the back shell member  104 . It is noted that while the illustrated example includes the cover  108  covering the lumbar support assembly, the seating arrangement  10  may also include variously configured back shell members that are not covered by a cover arrangement, where the back shell member itself provides the forwardly-facing surface upon which the back of a seated user is supported, or may also include other layers of material such as comfort surfaces, molded foam inserts, and the like. In the illustrated example, the back frame member  102  comprises a metal such as aluminum, and includes a horizontally extending upper frame portion  110 , a horizontally extending lower frame portion  112 , a pair of side frame portions  114  extending vertically between the upper frame portion  110  and the lower frame portion  112 . The back frame member  102  further includes a horizontally extending intermediate frame portion  118  extending between the side frame portions  114  and positioned between the upper frame portion  110  and the lower frame portion  112 . The upper frame portion  110 , the intermediate frame portion  118  and the side frame portions  114  cooperate with one another to form an open interior space  120  over which the back shell member  104  extends. The upper frame portion  110 , the intermediate frame portion  118  and the side frame portions  114  are each provided with a U-shaped cross-sectional configuration, thereby providing a forwardly opening channel  122  extending about the periphery of the interior space  120 . The frame portion  112  may further include a plurality of integral tab members  124  extending into the frame portion  112  and spaced about the periphery of the interior space  120 . 
     The back shell member  104  ( FIGS.  9  and  10   ) includes a horizontally extending upper shell portion  126 , a horizontally extending bottom shell portion  128 , and a pair of side shell portions  130  extending vertically between the upper shell portion  126  and the bottom shell portion  128 . The back shell member  104  further includes a plurality of horizontally extending, flexibly resilient straps  132  extending between the side shell portions  130 , and cooperating to define a plurality of slots  133  therebetween. In the present embodiment, the back shell member  104  is provided a forwardly-facing convex configuration along a centrally located longitudinally-extending axis, and a forwardly facing concave configuration along a centrally located laterally-extending axis. In the illustrated example, the straps  132  are concentrated toward an upper portion of the overall back shell member  104 , wherein the lowermost strap  134  of the plurality of straps  132  and the bottom shell portion  128  cooperate to define an open interior space  136  within which the lumbar assembly  106  is positioned. However, other configurations for the back shell member  104  may also be provided, wherein the lumbar assembly  106  is absent and the straps  132  extend across the entire interior space  136  between the upper shell portion  126  and the lower shell portion  128 . Other configurations of the straps  132  may also be utilized, including angled or curved configurations. Moreover, while the present embodiment of the back shell member  104  comprises an integrally molded, single-piece unit, other configurations may also be employed, including multi-piece configurations. The back shell member  104  further includes a tab member  138  that extends about the majority of the outer periphery of the back shell member  104  except for the corners  140  of the back shell member  104  located between bottom shell portion  128  and the side shell portions  130 . The tab member  138  includes a plurality of apertures  142  extending therethrough and spaced along a length of the tab member  138  that extends along the side shell portions  130 , and a plurality of apertures  144  extending therethrough and spaced along a length of the tab member  138  that extends along the top shell portion  126 , where the apertures  142 ,  144  are utilized to couple the back shell member  104  to the back frame member  102 , as described below. 
     The lumbar assembly  106  ( FIGS.  9  and  11 A ) includes a housing assembly  146  that includes a forward shell member  148  and a rearward shell member  150 . In the embodiment as illustrated, the forward shell member  148  includes a forwardly-facing support surface  152  having forwardly-facing convex shape along the vertical extent thereof, and a laterally-extending, forwardly-facing, concave shape along the lateral length. The forward shell member  150  further includes a pair of attachment tabs  154  extending outwardly from ends thereof and recessed rearwardly from the support surface  152 . The forward shell member  148  further includes a pair of centrally located apertures  156  configured to receive mechanical fasteners such as screws  158  therethrough. The rearward shell member  150  is provided an overall configuration similar to the forward shell member  158 , and includes a peripherally-extending outer wall  160 , a pair of apertures  162  located proximate the outward ends of the rearward shell member  150 , and a pair of forwardly-extending mounting bosses  164  configured to threadably receive the screws  158  therein. The lumbar assembly  106  further includes a forwardly-concave shaped leaf spring member  166  and a pair of mounting members  168  coupled to ends  167  of the spring member  166 . As best illustrated in  FIG.  11 B 1   , each mounting member  168  includes a slot  170  defined about a boss  171  and within which the ends  167  of the spring member  166  are received, a tab  172  received within the corresponding aperture  162  of the rearward shell member  150 , and a hook arrangement  174  slidably received within the channel  122  of the side frame portions  114  of the back shell member  104 , as described below. 
     In assembly, the spring member  166  and the mounting members  168  are coupled with the rearward shell member  150  by inserting the ends  167  of the spring member  166  into corresponding apertures  162  of the rearward shell member  150  and position the ends  167  of the spring member  166  within the slots  170  of the mounting members  168 . The forward shell member  148  is then coupled with the rearward shell member  150  by inserting the tabs  154  of the forward shell member  148  into the recesses  162  of the rearward shell member  150 , and then inserting the screws  158  through the apertures  156  of the forward shell member  148  and threading the screws  158  into the mounting bosses  164  of the rearward shell member  150 . The lumbar support assembly  106  ( FIGS.  9  and  13   ) is then coupled to the back frame member  102  by inserting the hook arrangement  174  of each of the mounting members  168  into the channels  122  of the side frame portions  114 . In the illustrated embodiment, each hook arrangement  174  includes a rearwardly-extending portion  176  received within the channel  122 , and a laterally inward extending portion  178  received within a laterally inward extending undercut portion  180  of the channel  122 . As the channel  122  and the undercut portion  180  thereof extends longitudinally along a length of the side frame portions  114 , the lumbar support assembly  106  is vertically adjustable within the space  136  of the back shell member  104 . A C-shaped spring member  181  ( FIGS.  11 B 1  and  13   ) extends about the hook arrangement  174  and includes an inwardly-extending central engagement portion  183  configured to engage a select one of a plurality of reliefs  185  ( FIG.  9   ) spaced along an interior surface of the channel  122 , thereby holding the lumbar assembly  106  at a selected vertical position. 
     As best illustrated in  FIG.  12   , the lowermost strap portion  134  of the back shell member  104  and the lumbar assembly  106  rearwardly deflect or move a similar distance when a rearwardly directed force is exerted thereto, thereby improving the comfort to the seated user. Specifically, the lower strap portion  134  of the back shell member  104  and the lumbar assembly  106  are configured such that the lowermost strap portion  134  and the lumbar assembly  106  each deflect in a rearward direction an amount X when the same rearward directed force F is exerted on both the lowermost strap  134  and the lumbar assembly  106  by the back of a seated user. In this manner, a front surface  135  of the lowermost strap  134  and the forwardly-facing support surface  152  remain aligned with one another along the forwardly-facing convex configuration of the back shell member  104  as the back shell member  104  and the lumbar assembly flex, thereby maintaining a smooth, comfortable support surface for the seated user. 
     An outer periphery  182  ( FIG.  13   ) of the cover  108  is directly sewn to the tab member  138  about a majority of the back shell member  104  by a plurality of stitches  184 . In the present embodiment, the outer periphery  182  of the cover  108  is directly attached to the tab member  138  along the entire length of the tab member  138 . As previously noted, the tab member  138  extends about the majority of the outer periphery of the back shell member  104 , with the exceptions being at the corners  140 . Other embodiments may include a tab member  138  that extends about the entire periphery of the back shell member  104  without interruptions therein, such that the outer periphery  182  of the cover  108  may be directly secured to the tab member  138  about the entire periphery of the back shell member  104 . Further, while in the illustrated example the outer periphery  182  is directly coupled to the tab member  138  via stitching, other suitable fastening arrangements may also be utilized, including adhesion, sonic welding, in-molding, and the like. 
     The assembly of the back shell member  104  and the cover  108  is attached to the back frame member  102  by inserting the tab member  138  of the back shell member  104  and the outer periphery  182  of the cover  108  into the channel  122  of the back frame member  102 , such that the tab member  138  of the back shell member  104  and the outer periphery  182  of the cover  108  are concealed from view within the channel  122  of the back frame member  102  subsequent to assembly. In the illustrated example, the hook arrangement  174  of the lumbar assembly  106 , the tab member  138  of the back shell member  104  and the outer periphery  182  of the cover  180  are all received within the same channel  122 , thereby reducing the overall packaging space for the related connections. In the illustrated example, the back shell member  104  is secured to the back frame member  102  by coupling the tab members  124  of the back frame member  102  with the associated apertures  142  of the back shell member  104 , and by a plurality of mechanical fasteners  183 ,  185 , as further described below. 
     The back frame member  102  further includes a plurality of integrally-formed abutment tabs  125  located within the U-shaped channel  122  of the back frame member  102  and spaced along the side frame portions  114 . The tabs  125  extend into the channel  122  from an inner wall  127  of each of the side frame members  114  and are configured to abut the tab  138  of the back shell member  104 , thereby limiting the inward deflection of the side shell portions  130  of the back shell member  104  in response to a rearwardly-directed force being exerted to the back shell member  104  by the back of a seated user. 
     In use, the housing assembly  146  of the lumbar support assembly  106  is configured to slide along the length of the spring member  166  in the directions  186 , thereby allowing the support surface  152  of the housing assembly  146  to center with respect to a seated user’s back when the user may not be centered with respect to the overall back assembly  20 . In the illustrated example, each end  188  of the housing assembly  146  is provided with a rearwardly-facing convex curved abutment surface  190  configured to abut a corresponding forwardly facing concave curved abutment surface  192  of the corresponding mounting member  168 . In operation, should the housing assembly  146  of the lumbar support assembly  106  slide into an off-center during rearward flexing of the back shell member  104  and movement of the user within the chair, the abutment surface  190  of the housing assembly  146  abuts the abutment surface  146  of the mounting member  168  as rearward flex of the back shell member  104  is reduced, thereby forcing the housing assembly  146  of the lumbar support assembly  106  toward a centered position within the interior space  136 . 
     The reference numeral  106   a  ( FIGS.  11 C- 11 E ) generally designates another embodiment of the lumbar assembly. Since the lumbar assembly  106   a  is similar to the previously described lumbar assembly  106 , similar parts appearing in  FIGS.  11 A and  11 B  and  FIGS.  11 C- 11 E , respectively, are represented by the same, corresponding reference numeral, except for the suffix “a” in the numerals of the latter. The lumbar assembly  106   a  ( FIGS.  11 C- 11 E ) includes a housing assembly  146   a , a pair of support handles  168   a , a spring member  166   a  extending between the handles  168   a , and a biasing member  167   a . The housing assembly  146   a  includes a forward shell member  148   a  and a rearward shell member  150   a . The spring member  166   a  is positioned between the forward shell member  148   a  and the rearward shell member  150   a , and the shell members  148   a ,  150   a  are connected together via hardware such as screws  158   a . The forward shell member  148   a  includes a forwardly-facing support surface  152   a , and a laterally-extending flexible slat  153   a  positioned between an upper portion  155   a  and a lower portion  157   a  of the support surface  152   a  and partially spaced therefrom by gaps or slots  149   a . The slat  153   a  is much more easily flexed in a fore-and-aft direction  159   a  than the overall housing assembly  146   a  and specifically the upper portion  155   a  and the lower portion  157   a  of the forward shell member  148   a . The biasing member  169   a , such as a coil spring, is positioned between the rearward shell member  150   a  and the slat  153   a  of the forward shell member  148   a , thereby biasing the slat  153   a  in a forward direction  161   a . The biasing force exerted by the biasing member  167   a  on the slat  153   a  is relatively small, such that the slat  153   a  is easily rearwardly displaced when contacted by the back of a seated user. The forward-positioned slat  153   a  defines the “S-point,” or forward-most point of the back assembly  20  in the lumbar area at the fore-to-aft median plane or centerline of the back assembly  20 , and provides a specific point from which the vertical adjustability of the lumbar assembly  106   a  with respect to an upper surface  107  ( FIG.  11 F ) of the seat assembly  18 . One method for determining the location of the S-point includes moving a vertical straight edge  109  horizontally rearward along the upper surface  107  of the seat assembly  18  until the straight edge touches the forward-most surface of the back assembly  20  located in the lumbar area at the centerline of the back assembly  20 , which in the instant example, would be the forward surface of the slat  153   a  of the forward shell member  148   a . Another method includes projecting a vertical laser beam from a “car” movable along a horizontal track until the beam illuminates the forward-most surface of the back assembly  20  located in the lumbar area at the centerline of the back assembly  20 . It is noted that if the forward-most surface of the back assembly includes a series of equidistant points, then the S-point is determined as the midpoint of this surface located within the lumbar area of the back assembly. By way of example, two relative vertical positions of the S-point are illustrated in  FIG.  11 F , including a lowered position I located at a vertical distance X from the upper surface  107  of the seat assembly  18  and a raised position J located at a vertical distance X′ from the upper surface  107  of the seat assembly  18 . In use, a rearward pressure exerted on the slat  153   a  by the back of a seated user flexes the slat  153   a  in a rearward direction such that the slat  153   a  is substantially flush with the upper portion  155   a  and the lower portion  157   a  of the support surface  152   a . The lumbar assembly  106   a  and the back assembly  20  may be configured such that the vertical travel of the S-point, as defined by the slat  153   a , with respect to the upper surface  107  of the seat assembly  18  is preferably at least 50 mm, more preferably at least 80 mm, and most preferably at least 100 mm. Further the lumbar assembly  106   a  and the back assembly  20  may be configured such that the S-point, as defined by the slat  153   a , is vertically adjustable with respect to the upper surface  107  of the seat assembly  18  a distance of preferably from equal to or less than about 170 mm to equal to or greater than about 250 mm, and more preferably from equal to or less than about 150 mm to equal to or greater than about 250 mm. 
     The control assembly  16  ( FIG.  14 A ) includes a housing member  194  operably coupled to a pedestal assembly  196  of the base assembly  12  ( FIG.  1   ), the slide support rails  74 , a forward link member  198  having a first end  200  pivotably coupled to a forward end  202  of each of the slide support rails  74  by a shaft member  204  for movement about a pivot axis  206  and a second end  208  pivotably coupled to the housing member  194  by a shaft member  210  for movement about a pivot axis  212 , and a rearward link member  214  having a first end  216  pivotably coupled to a rearward end  218  of each of the slide support rails  74  by a shaft member  220  for movement about a pivot axis  222  and a second end  228  pivotably coupled to the housing member  194  by a shaft member  230  for movement about a pivot axis  232 . The housing member  194 , the slide support rails  74 , the forward link member  198  and the rearward link member  230  cooperate to form a four-bar linkage assembly  231  that allows the back assembly  20  ( FIGS.  2 ,  14 A and  14 B ) to move between the upright position C and the reclined position D, and the seat assembly  18  to move between the upright position E and the reclined position F. 
     Each of the slide support rails  74  ( FIG.  14 A ) are provided with a forwardly located elongated aperture  240  and a rearwardly located elongated aperture  242  configured to slidably receive the shaft member  204  and the shaft member  220  therein, respectively. In assembly, an end  244  of the shaft member  204  and an end  246  of the shaft member  220  are coupled to the forward link member  198  and the rearward link member  214  and slidably received within the elongated apertures  240 ,  242 , respectively, such that each of the shaft members  204 ,  220  are adjustable along the length of the apertures  240 ,  242  in directions  248 , respectively. Subsequent to pre-assembly of the shafts  204 ,  220  within the apertures  240 ,  242 , the relative position of the components of the four-bar linkage assembly  231  may be adjusted relative to one another by sliding the ends  244 ,  246  of the shafts  204 ,  220  in the directions  248  to ensure proper alignment of the components relative to one another, to reduce “slop” within overall assembly due to stack-up tolerances, and/or to ensure proper orientation of the back assembly  20  and/or the seat assembly  18  when in the respective fully upright position thereof, and the like. The proper alignment may be determined by securing the four-bar linkage assembly  231  within a fixture, by pre-markings on one or more of the components of the four-bar linkage assembly  231 , by adjusting the four-bar linkage assembly  231  until stop members within the system are reached, by visual alignment, or other methods suitable for assuring proper alignment. Subsequent to determining the proper alignment and positioning the four-bar linkage assembly  231  in a proper configuration, the ends  244 ,  246  of the shaft members  204 ,  220  are secured to the associated frame rail supports  74  via orbital riveting, welding, and the like. 
     The back assembly  20  is coupled to the control assembly  16  by a quick-connect arrangement  250  ( FIG.  9   ), that includes a coupling portion  252  ( FIGS.  15 A- 15 C ) integrally molded with the lower frame portion  112  of the back frame member  102 , and a locking arrangement  254  ( FIGS.  16 A- 16 B ). In the illustrated example, the coupling portion  252  extends forwardly from the lower frame portion  112  of the back frame member  102  and includes a laterally-extending, U-shaped upper channel  256 , a laterally-extending, U-shaped lower channel  258  offset below and rearwardly from the upper channel  256 , and a pair of inwardly-extending pivot bosses  260 . The locking arrangement  254  includes a primary locking arrangement  262  and a secondary locking arrangement  264 . The primary locking arrangement  262  includes a locking portion  266  that includes a pair of outwardly and oppositely disposed recesses  268  each accessible via an end slot  270 , and an abutment surface  272 . The primary locking arrangement  262  further includes a leaf spring  264  having a clip portion  276  that clips to the primary locking portion  266 , and a biasing portion  278 , where the clip portion  276  and the biasing portion  278  each include downwardly extending fingers  280  configured to engage the coupling portion  252  of the back frame member  162 . The secondary locking arrangement  264  includes a secondary locking portion  282  that includes a release portion  284  and an abutment portion  286 , and is pivotably coupled to the locking portion  266  of the primary locking arrangement  262 . The secondary locking arrangement  264  further includes a spring member  288  that biases the release portion  284  and the abutment portion  286  as described below. 
     The back assembly  20  is assembled with the control assembly  16  by aligning the back assembly with the control assembly  16  such that the upper channel  256  of the coupling portion  252  is aligned with the shaft member  220  of the control assembly. The back assembly  20  is moved in a forward direction with respect to the control assembly until the shaft member  222  is at least partially received within the upper channel  256 . The back assembly  20  is then moved forward in the forward direction and simultaneously rotated in a downward direction, thereby forcing the shaft member  230  into the lower channel  258  and the locking arrangement  254  moves to a locked position. As best illustrated in  FIGS.  17 - 19   , the shaft member  230  and/or one of a pair of bushing members  302  abut the release portion  284  of the secondary locking arrangement  264 , thereby moving the release portion  284  and the abutment portion  286  from a locked position to an unlocked position and allowing the shaft member  232  to pass into the lower channel  258 . As the shaft member  230  passes into the recess  258 , the locking portion  266  rotates downwardly until the abutment surface  272  of the locking portion  266  abuts the bushing members  302 . Once the shaft member  230  is seated within the lower channel  258 , the abutment portion  286  of the secondary locking portion  282  is biased by the spring member  288  from an unlocked position to the locked position where the abutment portion  286  abuts an interior wall of the channel  258 . It is noted that the primary locking arrangement  262  cannot be moved from the locked position to the unlocked position unless abutment portion  286  of the secondary locking arrangement  264  is first moved from the locked position to the unlocked position thereof. The abutment portion  286  of the secondary locking portion  282  may be moved from the locked position to the unlocked position by exerting pressure on the release portion  284  in a direction of  304 , either by hand or with the assistance of a tool. Once the abutment portion  286  of the secondary locking portion  282  is moved from the locked position to the unlocked position thereof, the locking portion  266  of the primary locking arrangement  262  may be moved from the locked position to the unlocked position, thereby allowing removal of the back assembly  20  from the control assembly  16 . 
     In some instances, the distance between the pivot axis  271  and the bushing members  302  may change due to stack-up tolerances, and/or because of wear within the overall seating arrangement over time. Therefore, the abutment surface  272  may include a plurality of notches  273  ( FIG.  16 B ) spaced along the length thereof. The distance from the pivot point  271  ( FIGS.  16 C and  16 D ) of the pivot bosses  260  to the trough of each of the notches  273  increases from the bottom of the primary locking portion  266  to the top thereof, i.e., R 2  is greater than R 1 . As previously discussed, the primary locking portion  266  is rotated downwardly so as to abut the bushing members  302 , thereby preventing the shaft  260  from being removed from within the recess  258 . The various distances R 1 , R 2 , etc. allow for this variation that may occur due to stack-up tolerance, wear of the components, and the like, by allowing the primary locking member  266  to continue to rotate downwardly and securely lock the shaft  230  and bushings  302  within the recess  258 . As the distance increases, either due to stack-up tolerances and/or system settling/wear, the primary locking member  266  continues to optimize the locking abutment and take up any slack within the system. 
     Turning now to  FIG.  20   , a primary biasing arrangement  306  includes a coil spring  308  that is configured to bias the back assembly  20  from the reclined position D toward the upright position C. In the illustrated embodiment, the coil spring  308  includes a coiled body portion  310  coiled about a spacer  312  that is positioned about the axle member  210 , a first end  314  biased against the housing member  194 , and a second end  316  biased against the shaft member  204  via a spacer/bearing member. In the illustrated example, the spacer/bearing member  318  includes a body portion  320  extending at least partially about the shaft member  204 , and a coupling portion  322  integrally formed with the body portion  320  and including a recess  324  within which the second end  316  of the coil spring  308  is received. The spacer/bearing member  318  is configured to hold the second end  316  of the spring  308  in place and functions as a bearing between the second end  316  of the spring  308  and the shaft member  204  as the back assembly is moved between the upright and reclined positions C, D. 
     In an alternative embodiment, the spacer/bearing member  318   a  ( FIG.  21   ) is configured so as to allow adjustment of the preset bias exerted by the coil spring onto the four-bar linkage arrangement  231 . The spacer/bearing member  318   a  is similar to the spacer/bearing member  318 , with the most notable exception being the inclusion of a plurality of recesses  324   a ,  324   b ,  324   c  in place of a single recess  324 . It is noted that each of the recesses  324   a ,  324   b ,  324   c  vary in depth with respect to one another such that the bottom of each of the recesses  324   a ,  324   b ,  324   c  is at a different distance from the axis  48  of the shaft member  244 . The varying depth of each of the recesses  324   a ,  324   b ,  324   c  allows the amount of preset tension exerted on the back assembly  20  by the primary biasing arrangement  306  to be preset during manufacture of the chair, and combines the preset adjustment arrangement within a bearing member, thereby reducing the relative overall packaging volume. It is noted that the present arrangement prevents a casual user from adjusting or manipulating the back-biasing pretension within the system without significant disassembly of the overall seating arrangement  10 . 
     An auxiliary biasing arrangement  326  ( FIG.  22   ) is configured to further bias the back assembly  20  from the reclined position D toward the upright position C, and is selectable between a neutral or non-boost position ( FIG.  23 A ), a boost or biasing position ( FIG.  23 B ) where the auxiliary biasing arrangement  326  provides an additional biasing force to the back assembly  20  from the reclined position D toward the upright position C, and a locked position ( FIG.  23 C ) where the back assembly  20  is prevented from moving from the upright position C toward the reclined position D. The auxiliary biasing arrangement  326  including a coil spring  328  includes a body portion  330  coiled about a positioning spacer  332  that is positioned about the axle member  210 , a first end  334  biased against the axle member  210  via a spacer/bearing member  336  that is similar in configuration to the spacer/bearing member  318  as previously described, and a second end  338  extending oppositely from the first end  334 . The auxiliary biasing arrangement  326  further includes an actuator arm  340  pivotably coupled along a length thereof to a pivot shaft  342  that is fixedly secured to the housing member  194 , such that the actuator arm  340  pivots about a pivot axis  344 . The actuator arm  340  further includes a first end  346  that includes a forwardly-opening channel  348  that receives the second end  338  of the spring  328 , and a second end  350  that includes a stop surface  352 . 
     In operation, a control input knob  354  may be grasped and turned by a user to move the auxiliary biasing arrangement  326  between the neutral, biasing and locked positions. The input knob  354  is pivotably fixed to an end of an input shaft  356  that extends laterally across and is rotatably coupled to the housing member  194 . An input gear  358  ( FIG.  24   ) is fixedly secured to an opposite end of the input shaft  356  from the input knob  354  and receives the input force exerted on the input knob  354  from the operator. The input gear  358  includes a plurality of teeth  360  spaced about an outer periphery thereof, an outer wall  362  extending about the periphery of the gear  358 , and a recess  364  extending into the outer wall  362 . An output gear  366  is fixed for rotation with an end of the member  300  pivot shaft  342 , and includes a plurality of teeth  368  spaced about an edge thereof. The output gear  366  further includes an alignment tooth  370  interspaced with the teeth  368  and that extends laterally outward from an outer face of the output gear  366 . In the illustrated example, the alignment tooth  370  is configured to be received within the relief  364  of the input gear  358 , thereby ensuring proper alignment of the output gear  366  with the input gear  358 . When in the neutral position as illustrated in  FIG.  23 A , the actuator arm  340  is positioned so that the actuator arm  340  does not engage the second end  338  of the spring  328 , such that the spring  328  does not exert a biasing force on the four-bar linkage assembly  231  to bias the back assembly  20  from the reclined position D toward the upright position C. In order to provide an auxiliary biasing force to the back assembly  20  from the auxiliary biasing arrangement  326 , the actuator arm  340  is moved to the auxiliary boost position as illustrated in  FIG.  23 B , such that the actuator arm  340  abuts the second end  338  of the spring  328  as the back assembly is moved from the upright position C toward the reclined position D, and the spring member exerts a force on the four-bar linkage assembly  231  thereby biasing the back assembly  20  from the reclined position D toward the upright position C. The actuator arm  340  may further be moved into a locking position as illustrated in  FIG.  23 C , such that the stop surface  352  of the second end  350  of the actuator arm  340  abuts a stop member  372  fixedly attached to the second link member  214 , thereby preventing the back assembly  20  from moving from the upright position C toward the reclined position D. 
     The reference  326   a  ( FIGS.  25  and  26   ) generally designates another embodiment of the auxiliary biasing arrangement within a control assembly  16   a . Since the auxiliary biasing arrangement  326   a  and the associated control assembly  16   a  are similar to the previously described auxiliary biasing arrangement  326  and control assembly  16 , similar parts appearing in  FIGS.  22 - 24    and  FIGS.  25  and  26    respectively are represented by the same, corresponding reference numeral, except for the suffix “a” in the numerals of the latter. In the illustrated example, the auxiliary biasing arrangement  326   a  includes a coil spring  374  having body portion  376  coiled about a spacer member  378  that is positioned about the shaft member  210   a , a first end  380  that engages a structural reinforcement member  382  having a first end pivotably coupled to the shaft member  210   a  and a second end pivotably coupled to the shaft member  204   a  so as to pivot with and structurally reinforce the forward link member  198   a , and a second end  384 . The auxiliary biasing arrangement  326   a  further includes an actuator arrangement  386  that includes a first cam member  388 , a second cam member  390  and an actuator arm  392  that is fixed to the second cam member  390 . Similar to as described above with respect to the auxiliary biasing arrangement  326 , the auxiliary biasing arrangement  326   a  is adjustable between a neutral position, a biasing position and a locked position. An operator may adjust the auxiliary biasing arrangement  326   a  between the various positions by grasping and turning the input knob  354   a  in the directions  355   a . The first cam member  388  is fixed for rotation with the housing member  194   a  while the second cam member  390  is fixed for rotation with the input shaft  356   a , such that rotation of the input knob  354   a  and the input shaft  356   a  drives the cam surfaces  394  of the first cam member  388  and the second cam member  390  against one another driving the second cam member  390  and the actuator arm  392  in a direction  396  against the bias of a biasing spring  398  that extends about and along the length of the input shaft  356   a . In the present embodiment, the cam surfaces  394  of the first cam member  388  and the second cam member  390  are graduated so as to allow selective positioning of the first cam member  388  and second cam member  390  with respect to one another. In a first position as illustrated in  FIG.  26   , the actuator arm  392  is not aligned with the second end  384  of the spring  374  such that the second end  384  of the spring  374  is free to rotate as the back assembly  20  is moved from the upright position C to the reclined position D without the spring  374  exerting a biasing force on the back assembly  20 . As the actuator arm  392  is laterally moved from the first position or neutral position to the second position or biasing position the actuator arm  392  aligns with the second end  384  of the spring  374 , such that when the back assembly  20  is moved from the upright position C toward the reclined position D the actuator arm  392  abuts the second end  384  of the spring  374  and the housing member  194   a , and such that the spring  374  is deflected and a biasing force is exerted on the four-bar linkage assembly  231   a , thereby biasing the back assembly  20  from the reclined position D toward the upright position C. As the actuator arm  392  is laterally moved from the second position or biasing position to the third position or locking position the actuator arm  392  aligns with the structural reinforcement arm  382  and the housing member  194   a , such that when a user attempts to move the back assembly  20  from the upright position C toward the reclined position D the actuator arm  392  abuts the structural reinforcement arm  382  and the housing member  194   a , thereby preventing movement of the back assembly  20  from the upright position C toward the reclined position D and effectively locking the back assembly  20  in the upright position C. 
     The reference  326   b  ( FIGS.  27 - 29   ) generally designates another embodiment of the auxiliary biasing arrangement within a control assembly  16   b . Since the auxiliary biasing arrangement  326   b  and the associated control assembly  16   b  are similar to the previously described auxiliary biasing arrangement  326   a  and the control assembly  16   a , similar parts appearing in  FIGS.  25  and  26   , and  FIGS.  27 - 29    respectively are represented by the same, corresponding reference numeral, except for the suffix “b” in the numerals of the latter. In the illustrated example, the control assembly  16   b  includes a housing member  194   b , a pair of slide support rails  74   b , and a rearward linkage member  214   b  having a first end  216   b  pivotably coupled to a rearward end  218   b  of the slide support rails  74   b  and a second end  228   b  pivotably coupled to the housing member  194   b  by a shaft member  230   b . The forward ends  202   b  of the slide support rails  74   b  float with respect to the housing member  194   b . A primary biasing arrangement  306   b  includes a coil spring  308   b , having a first end biased against the housing member  194   b  and a second end  316   b  biased against the slide support rails  74   b  at a location  400 , thereby biasing the slide support rails  74   b  in a direction  402  with respect to the housing member  194   b . 
     The auxiliary biasing arrangement  326   b  includes a pair of coil springs including a first coil spring  404  and a second coil spring  406 . The first coil spring  404  and the second coil spring  406  each include a body portion  408  coiled about a spacer  410  positioned about the shaft member  230   b , and a first end (not shown) operably coupled to the back assembly  20  or a linkage member operably supporting the same. The first coil spring  404  includes a second end  412  while the second spring  406  includes a second end  414 . The auxiliary biasing arrangement  326   b  further includes an actuator arrangement  416  that includes a cam wheel  418  having a first radially extending track  420  and a second radially extending track  422  each defined by a plurality of radially extending guide walls  424  between which the ends  412 ,  414  of the springs  404 ,  406  guide as described below. The first track  420  includes a laterally extending first cam wall  430  while the second track  422  includes a laterally extending second cam wall  432  radially spaced from the first cam wall  430 . As best illustrated in  FIG.  28   , second end  412  of the first spring  404  tracks within the first track, while the second end  414  of the second spring  206  tracks within the second track  422 . In operation, an operator may adjust the auxiliary bias exerted on the back assembly  20  for biasing the back assembly  20  from the reclined position D toward the upright position C by grasping and rotating the input knob  354   b  in the directions  355   b . The cam wheel  418  is fixed for rotation with the input knob  354   b  via the input shaft  356   b . Rotation of the cam wheel  418  causes the first cam wall  430  and the second cam wall  432  to contact the ends  412 ,  414  of the first and second springs  404 ,  406 , causing the springs  404 ,  406  to deflect increasing the bias force exerted on the back assembly  20  at selected positions of recline of the back assembly  20 . It is noted that the radially offset locations of the first cam wall  430  and the second cam wall  432  with respect to one another causes the first cam wall  430  to engage the second end  412  of the first spring  404  prior to engagement of the second end  414  of the second spring  406  by the second cam wall  432  such that the auxiliary force exerted on the back assembly  20  increases as the angle of recline is increased. The present embodiment allows an operator to determine at which point during the recline of the back assembly  20  from the upright position C to the reclined position D the auxiliary biasing force exerted by the auxiliary biasing arrangement  426   b  is exerted on the back assembly  20 . 
     The control assembly  16  ( FIGS.  30  and  31   ) further includes a pneumatic height control adjustment assembly  450  configured to allow the user to adjust the overall height of the seating arrangement  10  between the lowered position G and the raised position H. In the illustrated embodiment, the height control adjustment assembly  450  includes a first link  452  fixed for rotation with a shaft  454  that pivots about the shaft member  210  and is fixed for rotation with an input lever  456 . The first arm  452  includes a first end  458  fixedly coupled with the shaft  454 , and a U-shaped second end  460  having a downwardly disposed first surface  462 . The height control actuator assembly  450  further includes a second link  464  pivotably coupled to the pivot shaft  342  at a first end  466 , and an upwardly disposed second surface  468  that extends along a length of a second end  470  of the second link  464 . In the illustrated example, the second surface  468  includes an upwardly disposed, convex first arcuate surface  472  positioned proximate a distal end of the second end  470 , and an upwardly disposed, convex second arcuate surface  474  positioned between the first arcuate surface  472  and the first end  466  of the second link  464 . The second link  464  further includes an actuator tab  476  positioned along the length thereof. 
     In operation, an operator may adjust the overall height of the seating arrangement  10  between the fully lowered and raised positions G, H, by activating a pneumatic cylinder arrangement  478  via the height control adjustment assembly  450 . To effect actuation, the operator grasps the actuator lever  456  and turns the actuator lever  456  in either of the directions  450 , thereby pivoting the actuator lever  456 , the shaft  454 , and the first link  452 . As the first link  452  rotates the first surface  462  of the first link  452  guides along one of the first arcuate surface  472  or the second arcuate surface  474  depending upon the direction of rotation of the actuation lever  456 . Tracking of the first surface  462  of the first link  452  along either of the arcuate surfaces  472 ,  474  causes the second link  464  to pivot about the pivot shaft  342  in a direction  482 , thereby causing the actuator tab  476  of the second link  464  to depress an actuator button  484  of the pneumatic cylinder arrangement  478 , thereby actuating the cylinder arrangement  478  and allowing the operator to adjust the height of the seating arrangement  10  from a lower position to a higher position by removing a downward force exerted on the seating arrangement  10  thereby allowing the pneumatic cylinder arrangement  478  to raise the height of the seating arrangement  10 , or by exerting a downward force on to the seating arrangement  10  thereby overcoming the force exerted on the seating arrangement  10  by the pneumatic cylinder arrangement  478  and lowering the overall height of the seating arrangement  10 . Once the desired height of the chair arrangement  10  has been reached, the operator releases the actuator lever  456 , thereby allowing a coil spring  486  to bias the actuator tab  476  away from the button  484  by rotating the second link  464  in a direction opposite to the direction  482 . In the illustrated example, the conical coil spring  486  is located proximate an end of the pneumatic cylinder arrangement  478  and is aligned therewith. It is noted that the first arcuate surface  472  and the second arcuate surface  474  are shaped such that the input force required to be exerted on the actuator lever  456  by the operator to actuate the pneumatic cylinder arrangement  478  are substantially the same regardless of the direction of rotation of the actuator lever  456 . 
     Each arm assembly  22  ( FIGS.  1  and  32   ) includes a column member  490 , a control assembly  492  received within the column member  490 , and an arm support assembly  494  supported on an end of the column member  490 . Each column  490  includes a first portion  496  telescopingly received within a bushing member  497  positioned within a receiver portion  498  of the back frame member  102 , such that the arm assembly  22  is generally vertically adjustable between a raised position and a lowered position with respect to the back frame member. The column member  490  further includes a second portion  500  that extends forwardly from the first portion  496  such that the second portion forms an angle of at least 45° with the first portion, and preferably an angle of at least 75° with the first portion, at a corner  501  located therebetween. The arm support  494  is operably coupled to the second portion  500  of the column member  490  such that the arm support  494  ( FIG.  33   ) is laterally adjustable between an inboard position I and an outboard position J, longitudinally adjustable between an aft position K and a fore position L, and rotatably adjustable between a forwardly facing position M, an outwardly rotated position N and an inwardly rotated position O. 
     As best illustrated in  FIG.  32   , the arm assembly  22  may also be provided as a conversion kit along with or separate from a pair of plug members  551 , where the arm assemblies  22  may be replaced with the plug member  551  to convert the seating arrangement  10  from an arm to an armless version, or vice versa. Each plug member  551  includes a column portion  553  similarly configured as the column portion  490  of the armrest  22  and adapted to be received within the receiver portion  498  of the back frame  102 , and an end wall  555  that blocks off an end of the column portion  553  thereby providing a finished aesthetic look and preventing access to the interior of the receiver portion  498 . In some embodiments, the plug member  551  may be configured to include accessory components or supports, including, but not limited to a bag hook, cup holder, tablet, phone or other device holder, or other personal accessories. 
     The control assembly  492  ( FIG.  34   ) includes a first link  502  having a first end  504  pivotably coupled to a support plate  506  of the arm support  492 , and a second end  508 . The first link member further includes an actuator portion  510  positioned along a length of the first link  502  between the first end  504  and the second end  508 . The control assembly  492  further includes a second link  512  having a first end  514  pivotably coupled to the second end  508  of the first link  502 , and a second end  516 . The second end  516  includes a biasing spring  518  that biases a plurality of locking teeth  520  of a locking member  522  into a locking engagement with a plurality of receiving teeth ( FIG.  35   ) integrally molded with the back frame member  102  within an interior of the receiver  498 . In the present embodiment, the pivot connection between the first link  502  and the second link  512  is preferably located proximate the corner  501  between the first portion  496  and the second portion  500 , and that the actuator portion  510  extends through an aperture in the bottom of the second portion  500  of the column member  490 , such that the actuator portion  510  is accessible along the length of the second portion  500  between the corner  501  and a distal end  526  of the column member  490 . 
     The reference  22   c  ( FIG.  36   ) generally designates an alternative embodiment of the arm assembly. Since the arm assembly  22   c  is similar to the previously described arm assembly  22 , similar parts appearing in  FIGS.  32 - 34    and  FIGS.  36 - 38    respectively are represented by the same, corresponding reference, except for the suffix “c” in the numerals of the latter. In the illustrated embodiment, the actuator portion  510   c  is pivotably received within an end cap  528 . The control assembly  492   c  ( FIG.  37   ) includes the actuator portion  510   c , a locking portion  530 , and a flexible connector portion  532 . The actuator portion  510   c , the locking portion  530  and the connector portion  532  are preferably constructed as an integral, one-piece unit that includes the entire actuator portion  510   c  and the entire locking portion  530 , including the plurality of locking teeth  520   c . In operation, an operator grasps a handle portion  534  of the actuator portion  510   c  moving the handle portion  534  in a direction  536  and an arm portion  538  in a direction  540  thereby bending a distal end of the connector portion  532  downwardly and drawing the connecting portion  532  in a direction  542  and disengaging the plurality of locking teeth  520   c  from the plurality of receiving teeth  524  of the receiver portion  498  of the back frame member  102 . 
     As best illustrated in  FIG.  32   , the arm support assembly  494  may include a plastic arm cap shell member  660 , an arm cap foam member  662 , and an arm cap cover arrangement  664  that includes an outer layer  666  comprising a thermoplastic polyolefin (TPO) and/or a thermoplastic elastomer (TPE) that is overmolded onto a connection ring  668 . In assembly, the foam member  662  is positioned within the arm cap cover arrangement  664 . The shell member  660  is then positioned within the cover arrangement  664  and snap-fit or connected via mechanical fasteners (not shown) to the connection ring  668 . The arm support assembly  494  is then connected to the second portion  500  of the column arm  490  via mechanical fasteners that extend through the second portion and into the shell member  660 . 
     In another alternative embodiment, the seating arrangement  10  ( FIG.  38   ) may be provided with a headrest assembly  550  and/or a garment hanger  552 . In the illustrated example, the headrest assembly  550  ( FIG.  40   ) includes a mounting structure  554  and a headrest member  556 . The mounting structure  554  includes a mounting portion  558  having an upwardly-opening, U-shaped cross-section configuration, and an overall configuration similar to the upper portion of the back frame member  102 , and an upwardly extending support stand  562  to which the headrest member  556  is vertically adjustably mounted. Alternatively, the mounting structure  554  for the headrest member  556  may be replaced by a garment hanger  552 , and/or the mounting structure  554  and the garment hanger  552  may both be combined onto a single mounting portion  558 . As best illustrated in  FIG.  41   , the upper back shell portion  126  of the back shell member  104  is secured to the upper frame portion  110  of the back frame member  102  via a pair of mounting clips  564  positioned between the upper shell portion  126  and the upper frame portion  110 , and including a forwardly extending hook  566  that extends into an aperture  568  of the back shell member  104 , and a pair of rearwardly extending hooks  570  extending into apertures  572  of the back shell member  104 . A plurality of mounting screws  574  extend through apertures  576  of the back frame member  102  and are received by the mounting clips  564 , thereby securing the top shell portion  126  of the back shell member  104  to the top frame portion  110  of the back frame member  102 . Alternatively, the screws  574  may be replaced by relatively longer screws  578  that can extend through the mounting portion  558  of the headrest assembly  550  and the upper frame portion  110  of the back frame member  102  and into the mounting clips  564 , thereby securing the headrest assembly  550  and the back shell member  104  to the back frame member  102 . As best illustrated in  FIG.  9 A , each mounting clip  564  includes a body portion  565  that threadably receives the associated screws 574/578, and a forwardly-extending engagement portion  567  that snappingly engages corresponding apertures  569  ( FIG.  9   ) of the back shell member  104 . The mounting clips  564  are each configured such that a front face  571  of the engagement portion  567  is substantially flush with a forwardly-facing surface  573  of the back shell member  104 , thereby completely filling the aperture  569  and providing a flush surface in cooperation with the back shell member  104 .