Patent Publication Number: US-6705678-B1

Title: Height-adjustable chair back

Description:
FIELD OF THE INVENTION 
     This invention relates to a chair as typically used in offices and the like and, more specifically, to a chair having an improved back arrangement employing a back shell slidably supported on a pair of uprights projecting upwardly from adjacent opposite sides of the chair seat, and which employs manually-releasable latching mechanisms cooperating with each of the uprights to permit height adjustment of the back arrangement. 
     This invention also relates to a chair of the type typically used in offices and the like which, more specifically, incorporates an improved adjustment mechanism cooperating with the chair arms for permitting manual adjustment of the arms into one of several different selectable positions. 
     BACKGROUND OF THE INVENTION 
     Chairs, and particularly office-type chairs, are conventionally provided with a height-adjustable back arrangement. Such arrangements are typically constructed from a significant number of different parts so that the resulting construction is complex and expensive to manufacture, and oftentimes bulky, so that the aesthetics of the back are impaired. Such back arrangements also frequently employ a height-adjusting mechanism positioned at least partially internally of the back arrangement, generally centrally thereof, and such mechanism further increases the structural complexity and spatial requirements of the back arrangement. The back height-adjusting mechanism is, in many instances, also disposed so that manual release thereof involves an actuator which is accessible solely from the back side of the chair, and as such the release actuator not only impairs the aesthetics of the chair back, but also is inconvenient to utilize since back height-adjustment can not be effected while the occupant remains seated in the chair. 
     Chairs, particularly those used in office or similar working environments, are also typically provided with arms disposed adjacent opposite sides of the seat, and such arms are frequently supported by appropriate adjustment mechanisms which permit the height and/or horizontal position of the arm to be selectively varied. While numerous mechanisms have been developed for permitting vertical or horizontal positional adjustment of chair arms, most of these mechanisms involve a large number of parts which result in undesired structural complexity and spatial requirements, and as such impair the desired aesthetics of the arm arrangement. 
     Accordingly, it is an object of this invention to provide an improved chair having a simplified height-adjustable back arrangement associated therewith. The back arrangement, in a preferred embodiment, is defined principally by a back shell provided with support parts, such as sleeves, adjacent opposite sides thereof. The support sleeves are slidably supported on respective uprights which are joined to and project upwardly adjacent opposite sides of the chair seat. A manually-releasable latching mechanism cooperates between each support sleeve and its respective upright whereby a seated occupant, by using right and left hands, can simultaneously release both latching mechanisms and effect vertical slidable displacement of the back shell to adjust the position thereof. 
     In the improved chair of this invention, as aforesaid, the uprights preferably function to support chair arms thereon adjacent upper ends thereof. The uprights are preferably positioned adjacent but spaced slightly forwardly from rear corners of the chair seat so as to provide desired overall chair aesthetics, and to improve occupant access to the releasable latching mechanisms. 
     In the improved chair of the present invention, as aforesaid, the chair arms are preferably supported within the uprights by releasable height-adjusting mechanisms which can be easily manually released by the seated occupant, and which permit the height of the individual chair arms to be vertically adjusted relative to the upright. The releasable height-adjusting mechanisms which control the height of the chair arms are confined within the uprights so as to be surrounded not only by the upright but also by the support sleeve associated with the chair shell, thereby providing a construction which is compact, space saving and aesthetically desirable. 
     It is also an object of the invention to provide a chair, such as an office type chair, having an improved adjustment mechanism associated with and cooperating between the chair arm and the support therefore so as to permit the position of the chair arm to be readily manually adjusted. The mechanism preferably incorporates a simplified height-adjusting mechanism which is confined within the support upright for the chair arm, which mechanism involves minimal structural parts and operational complexity so as to provide a simple and compact operating arrangement. The mechanism preferably includes a release button which can be easily manually released and is positioned directly under the chair arm for ease of operation. The release button couples to an elongate trigger rod which projects vertically interiorly of the upright and, at its lower end, has an integral cam part which cooperates with and effects sideward movement of a latch plunger which is normally spring-urged into latching engagement with one of a series of latching shoulders or steps defined vertically along one side of the upright. 
     In the chair of the present invention, as aforesaid, the mechanism which permits movement of the chair arm also preferably incorporates a lift-and-lock mechanism cooperating with the chair arm to permit the latter to be horizontally angularly displaced between a plurality of distinct positions. This mechanism enables the chair arm to be manually lifted and then angularly displaced into a desired position, followed by lowering of the arm to lock it in the desired position. The lift-and-lock mechanism permits angular displacement to occur without affecting or disturbing the height-adjusting mechanism which is coupled therebelow and is disposed within the supportive upright. 
     Other objects and purposes of the invention, including structural and operational advantages thereof, will be apparent to persons familiar with constructions of this general type upon reading the following specification and inspecting the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a chair embodying therein the present invention. 
     FIG. 2 is a front elevational view of the chair shown in FIG.  1 . 
     FIG. 3 is a side elevational view of the chair shown in FIG.  1 . 
     FIG. 4 is a rear elevational view of the chair shown in FIG.  1 . 
     FIG. 5 is a rear perspective view of the back shell of the chair, with the height-adjusting mechanisms associated therewith shown in exploded view. 
     FIG. 6 is a top view of the back shell shown in FIG.  5 . 
     FIG. 7 is a sectional view taken generally along line  7 — 7  in FIG.  6 . 
     FIG. 8 is an enlarged, fragmentary back view showing the mounting part associated with one side of the back shell. 
     FIG. 9 is a fragmentary sectional view taken generally along line  9 — 9  in FIG.  8 . 
     FIG. 10 is a fragmentary sectional view taken generally along line  10 — 10  in FIG.  9 . 
     FIG. 11 is a rear elevational view showing the actuating paddle which mounts to the mounting part of the back shell. 
     FIG. 12 is a side elevational view of the actuating paddle shown in FIG.  11 . 
     FIG. 13 is a top view of the actuating paddle shown in FIG.  11 . 
     FIG. 14 shows the U-shaped arm member of the chair and its association with the back shell. 
     FIG. 15 is an enlarged, fragmentary cross sectional view taken through the arm mounting part of the back shell and showing the height-adjusting mechanism in its latched position. 
     FIG. 16 is a view corresponding to FIG. 15 but showing height-adjusting mechanism in an unlatched position. 
     FIG. 17 is a top view showing the latching lever associated with the back shell height adjustment mechanism. 
     FIG. 18 is a side view of the latching lever shown in FIG.  17 . 
     FIG. 19 is a diagrammatic plan view taken generally along line  19 — 19  in FIG.  2 . 
    
    
     Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly”, “leftwardly” will refer to directions as appearing in the drawings, and will also refer to the same directions with respect to an occupant seated in the chair. The words “inwardly”, “outwardly” will refer to the geometric center of the chair and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     DETAILED DESCRIPTION 
     Referring to FIGS. 1-4, there is illustrated a chair  10  according to the present invention, which chair is of the type conventionally used in offices and the like. The chair  10  includes a seat  11  which projects forwardly from an upwardly projecting back  12 . A pair of arm rest assemblies  13  are movably supported on uprights  14  which project upwardly from adjacent opposite sides of the seat  11 . A conventional chair control arrangement  16 , which defines a generally horizontal tilt axis  17 , connects the seat  11  to the upper end of an upright pedestal  18 , the latter typically having a height-adjusting air spring associated therewith. The pedestal  18  at its lower end couples to a conventional base  19 , the latter typically having a plurality of radially outwardly projecting legs provided with casters adjacent the outer ends thereof. 
     The back  12  is defined principally by a monolithic one-piece back member or shell  21  which is typically formed of a synthetic resin material such as a plastics material. This one-piece back member  21 , as illustrated in FIGS. 5-7, includes a main upright panel  22  which defines the dominant horizontal and vertical extent of the chair back for supportive engagement with the back of a seated occupant. The main panel  22  extends vertically between respective upper and lower edges  23  and  24 , and extends horizontally between opposite side edges  26 . 
     The back member  21  also includes mounting parts  27  which are monolithically and integrally fixed to and project outwardly from opposite sides of the main panel  22  in the vicinity of the lower end thereof for permitting coupling of the back member  21  to the arm uprights  14 . The mounting parts  27  project outwardly and forwardly relative to the respective adjacent side edge of the main panel  22 , and each includes a generally vertically elongate support sleeve  28  having a generally vertical and cylindrical opening  29  extending therethrough for accommodating the respective arm upright  14  as described below. 
     The arm uprights  14  are cantilevered upwardly in generally parallel relation from adjacent opposite sides of the chair seat  11  generally in the vicinity of the rear corners thereof. The arm uprights  14  are part of a generally U-shaped arm member  31  (FIG. 14) which has a center part  32  thereof disposed under the chair seat and rigidly joined relative thereto, such as by being secured to a part of the housing associated with the chair control. The center part  32  joins through bends  33  to the uprights  14 . The U-shaped chair member  31  may be formed from a one-piece tubular element, or may be formed from two L-shaped tubular pieces which are mirror images of one another and joined to the chair seat so as to provide a generally U-shaped arrangement. 
     The back member  21  is vertically slidably supported on the arm uprights  14 , and a manually-releasable latching mechanism  34  (FIGS. 15-16) cooperates between each mounting part  27  and its respective arm upright  14  for controlling the vertical position of the back member. 
     The latching mechanism  34  includes a pivoting latching lever  36  which is adapted for latching engagement within one of a plurality of slots  37  which are formed in and extend transversely relative to the exterior surface of the arm upright  14 . The latching lever  36  is acted on by spring  38  which biases the latching lever into its latching position. An activating member or paddle  39  is hingedly mounted on the support sleeve  28  of the chair shell and cooperates with the latching lever  36  for permitting the latter to be moved into a released or unlatched position. 
     To accommodate the latching mechanism  34 , and referring specifically to FIGS. 8-10, the support sleeve  28  associated with the back member  21  has a generally T-shaped opening  41  which extends transversely through the back side of the support sleeve for communication with the cylindrical opening  29  defined interiorly thereof. The T-shaped opening  41  is oriented generally horizontally and includes a generally rectangularly-shaped main opening  42  which, along a vertical edge thereof closest to the main panel of the chair back, is provided with slot-like parts  43  which are elongated upwardly and downwardly from the respective upper and lower edges of the main opening  42 . The T-shaped opening  41  also includes a horizontally elongate narrow slot  44  which projects transversely away from the vertical edge of the main opening  42  which has the slot-like parts  43  associated therewith. The elongate narrow slot  44 , at the end thereof remote from the main opening  42 , communicates with a blind bore  46  which opens inwardly from the exterior rear surface where the support sleeve  28  merges into the main panel of the back member substantially as illustrated in FIG.  9 . 
     The support sleeve  28  of the back shell has a first vertically elongate slot-like groove  48  formed inwardly from the inner sleeve wall  47 , which groove  48  communicates with the narrow slot  44  adjacent the remote end thereof, that is, in the vicinity of the blind bore  46 . This groove  48  extends vertically on both sides of the narrow slot  44 , and accommodates therein a hinge pin associated with the latching lever  36  as discussed hereinafter. 
     The support sleeve  28  also has a further slot-like groove  49  which opens inwardly from the inner sleeve surface  47  and extends vertically therealong. This groove  49  extends vertically generally along the edge of the main opening  42  which is on the side thereof remote from the narrow slot  44 . Groove  49  also projects vertically both above and below the respective upper and lower edges of the main slot  42  so as to accommodate therein a hinge pin associated with the activating paddle  39 , as discussed hereinafter. 
     The inner surface  47  of the support sleeve  28  also has a plurality of ribs  51  extending vertically therealong in angularly spaced relationship therearound. Each of these ribs defines thereon a inner contact surface  52  which is of a partial cylindrical configuration whereby the plurality of contact surfaces  52  provides a snug but slidable supportive engagement with the arm upright  14 . 
     Considering now the construction and function of the latching mechanism  34  in greater detail, the latching lever  36  as illustrated in FIGS. 17-18 includes first and second lever parts  56  and  57 , respectively, which project generally outwardly in opposite directions from a center hub or pivot pin  58 , the latter projecting transversely outwardly from opposite sides of the lever member. The lever member also has a nub or pin  59  projecting outwardly from one side of the lever part  57  at a location disposed more closely adjacent the outer free end thereof. The first lever part  56  also defines a flat edge  61  extending outwardly along one side thereof. 
     The lever member  36  is positionally and pivotally supported on the support sleeve  28  of the chair back by initially inserting the first lever part  56  into the interior of the support sleeve  28 , such being accomplished by inserting the lever part  56  and the center pivot  58  through main opening  42 . When so disposed the pivot pin  58  of the lever is snapped into the slot-like groove  48 , with the lever parts being positioned within and projecting out through the narrow elongate slot  44 . The second lever part  57  projects outwardly through the slot  44  so that the outer end of the second lever part  57 , and specifically the nub  59  thereon, is aligned generally with the blind bore  46 . The spring  38  has one end thereof seated in the blind bore, and the other end fitted over the projection or nub  59 , whereby the spring  38  urges the latching lever to pivot about the pivot pin  58  so that the flat surface  61  on the first lever part  56  is always urged radially inwardly toward a position of latching engagement with the arm upright  14 . In this regard, the arm upright as noted above has a plurality of vertically spaced slots  37  extending transversely across the outer surface thereof, which slots  37  each have a flat bottom wall  62  adapted for engagement with the flat edge  61  on the first lever part  56  when the latter is in a latched position wherein it is engaged within one of the slots. 
     The latching mechanism also includes the activating member or paddle  39 , the latter also effectively functioning as a shroud for enclosing the latching mechanism. This activating paddle  39  as illustrated in FIGS. 11-13 includes a main panel part  63  which, in cross section, has a generally arcuate configuration similar to the outer configuration of the support sleeve  28 . The panel part  63  of the paddle  39  has a flange  64  associated with one upright edge thereof, the latter in turn being joined to a vertically elongate hinge pin  66  which is offset inwardly from the panel  63  and flange  64 . The hinge pin  66  is of sufficient vertical extent that upper and lower edge portions thereof project respectively vertically above and below the extremities of the flange  64  as illustrated in FIGS. 11-12. A plurality of reinforcing ribs  67  couple the pin  66  and flange  64  to the main panel part  63 . The main panel part  63  of the paddle  38  has, adjacent the opposite longitudinally extending vertical edge  68  thereof, a small pin or nub  69  protruding inwardly therefrom at a location which is approximately horizontally aligned with the center of the flange  64 . 
     The activating paddle  39  is mounted to the support sleeve  28  by initially positioning the paddle adjacent the T-shaped opening  41  so that the hinge pin  66  on the paddle is aligned with the slot-like parts  43  associated with one edge of the main opening  42 . The paddle is then moved inwardly so that the hinge pin  66  passes through the slot-like openings  43 , with the hinge pin then being moved transversely across the main opening  42  so as to be aligned with and snapped into the slot-like groove  49  disposed adjacent the other edge of the main opening  42 . When so positioned, the main panel part  63  of the paddle  39  effectively overlies the entirety of the T-shaped opening  41 , and the free edge  68  of the paddle is disposed such that the protrusion  69  is positioned to abuttingly contact a back surface  71  provided on the free end of the second lever part  57  substantially as illustrated in FIGS. 15-16. 
     The spring  38  acting against the latching lever swings the latter outwardly (clockwise in FIG. 15) which in turn acts against the free end of the paddle  39  to swing the latter outwardly into the latched position as illustrated by FIG.  15 . In this latched position, the outward swinging of the paddle  39  is restricted by the opposed stop surfaces  72  on the paddle and  73  on the support sleeve contacting one another. In this latched position, however, the spring  38  exerts little, if any, biasing force. 
     When the latch is to be released, however, the paddle  39  is manually depressed toward the support sleeve  28  and pivoted inwardly (counter-clockwise in FIG. 15) into the position illustrated in FIG.  16 . In this position, the free end of the paddle  39  acts against the end of lever part  57  causing the latter to be moved inwardly to effect compression of the spring  38 , and simultaneously causing the latching lever part  56  to be swung outwardly so as to disengage the latching slot  37 . 
     With the arrangement of the present invention, the height of the back member  21  can be adjusted relative to the chair seat  11  while the user of the chair is seated. To effect such height adjustment, the seated occupant reaches down and somewhat rearwardly so as to engage right and left hands with the respective right and left mounting parts of the chair back. The hands are positioned so that the fingers project outwardly around the support sleeves for engagement with the respective activating paddles  39 . The fingers on both hands are then simultaneously pressed against the activating paddles  39  so that the paddles swing inwardly into the unlatching position illustrated in FIG.  16 . During this inward swinging of the activating paddles, the free end of the activating paddle acts against the lever part  57  of the latching lever and swings it inwardly about pivot  58  causing compression of the spring  38 . This causes the first lever part  56  to swing outwardly so as to disengage the slot  37  on the arm upright  14 . With both latches disengaged, and with the occupant&#39;s hands continuing to grip the support sleeves  28 , the user can then manually slide the back member  21  upwardly or downwardly on the arm uprights  14  to the desired elevation. When reaching the desired elevation the user releases finger pressure on the paddle members  39  so that the springs  38  urge the latching levers back toward the latching positions and simultaneously swing the paddle members outwardly to the latched position illustrated by FIG.  15 . If the latching lever does not directly align with one of the slots  37 , then the user can slidably displace the back member a small vertical distance until the latching levers are spring urged into the nearest adjacent slot  37 . 
     Since the latching members automatically remain in the latched position due to cooperation with the coil springs  38 , the chair hence can be readily moved about and even lifted by gripping the back member, without causing movement or separation of the back with respect to the remainder of the chair. 
     The back member  21  is preferably formed as a monolithic one-piece shell constructed of a plastics material and is suitably contoured so as to comfortably support the user&#39;s back, with the construction of the shell providing sufficient resiliency to enhance user comfort. It will be appreciated, however, that the back shell can also be provided with cushions and/or upholstered coverings thereover, as is conventional in chair constructions, if desired. 
     Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.