Abstract:
An adjustable armrest assembly for a chair includes a mounting member connected to the chair. The mounting member has an upper base. A first horizontal slide element is slidably mounted to the upper base and is adjustably slidable in a first direction with respect to the upper base. The first slide element is restrained after adjustment with respect to the upper base by frictional engagement between the upper base and the first slide element. A second horizontal slide element for slidably mounting to the first slide element is slidable in an arcuate path crossing the first direction. The second slide element is restrained after adjustment with respect to the first slide element by frictional engagement between the second slide element and the first slide element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Provisional Application Ser. No. 60/953,213, filed Aug. 1, 2007, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to an adjustable armrest for a chair. More particularly, the present invention relates to an adjustable armrest for an office chair, the armrest being capable of moving in a first direction and rotating in a path that crosses the first direction. 
       BACKGROUND 
       [0003]    Adjustable armrests now appear in many office chairs. Some adjust laterally, that is, away from or in toward a chair user. Others move longitudinally, forwardly and backwardly, relative to the chair and the user. Still others swivel in a horizontal plane or tilt about a horizontal axis. In other cases, chairs have armrests that put two or more of the above mentioned movements together. 
         [0004]    Examples of adjustable armrests are shown in U.S. Pat. Nos. 7,066,546, 6,802,566, 6,592,085, 6,572,195, 6,213,556, 6,059,366, and 6,017,091. 
       SUMMARY 
       [0005]    In one aspect of the present invention, an adjustable armrest assembly for a chair includes a mounting member connected to the chair. The mounting member has an upper base. A first horizontal slide element is slidably mounted to the upper base and is adjustably slidable in a first direction with respect to the upper base. The first slide element is restrained after adjustment with respect to the upper base by frictional engagement between the upper base and the first slide element. A second horizontal slide element for slidably mounting to the first slide element is slidable in an arcuate path crossing the first direction. The second slide element is restrained after adjustment with respect to the first slide element by frictional engagement between the second slide element and the first slide element. 
         [0006]    In another aspect of the present invention, an adjustable armrest assembly for a chair includes a mounting member connected to the chair. The mounting member has an upper base. A first horizontal slide element is slidably mounted to the upper base and is slidable in a first direction with respect to the upper base. The first slide element maintains after adjustment a substantially fixed position with respect to the upper base by frictional engagement. A second slide element is slidably mounted to the first slide element in an arcuate path that crosses the first direction. 
         [0007]    In a further aspect of the present invention, an adjustable armrest assembly for a chair includes a mounting member connected to the chair. The mounting member has an upper base. The upper base includes first and second guide rails extending in a first direction, and first and second spaced apart fastener receiving openings. A first elongated slide structure is mounted to the upper base and extends in the first direction. The first slide structure includes a first elongated slot aligning with the first and second fastener receiving openings of the upper base and extending to a distance greater than the distance between the first and the second fastener receiving openings of the upper base. A lower surface engages the first and the second guide rails of the upper base. An upper surface has first and second guide rails that extend in a first arcuate path that crosses the first direction, and third and fourth spaced apart fastener receiving openings. A second elongated slide structure is mounted to the first slide structure and extends in the first direction. The second slide structure includes second and third elongated slots. The second slot is aligned with the first fastener receiving opening of the upper surface of the first slide structure, and the third slot is aligned with the second fastener receiving opening of the upper surface of the first slide structure. The second and third slots extend in a second arcuate path that crosses the first direction, and a lower surface has first and second elongated recesses for engaging the first and second guide rails of the upper surface of the first slide structure. 
         [0008]    A more complete understanding of the present invention and other objects, advantages and features thereof will be gained from a consideration of the following description of a preferred embodiment read in conjunction with the accompanying drawing provided herein. The preferred embodiment represents an example of the invention which is described here in compliance with 35 U.S.C. §112 (first paragraph), but the invention itself is defined by the attached claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an isometric view of an office chair with adjustable armrests. 
           [0010]      FIG. 2  is an exploded isometric view of one of the adjustable armrests. 
           [0011]      FIG. 3  is another exploded isometric view of the adjustable armrest rotated about 90 degrees from the view shown in  FIG. 2 . 
           [0012]      FIG. 4  is an exploded side elevation view of the armrest shown in  FIGS. 2 and 3 . 
           [0013]      FIG. 5  is a partial, sectional front elevation view of the armrest shown in  FIGS. 2-4 . 
           [0014]      FIG. 6  is an isometric view of a mounting member with an upper base telescopically extending from a support. 
           [0015]      FIG. 7  is a top plan view of the upper base. 
           [0016]      FIG. 8  is an isometric view of a first slide element of the armrest shown in  FIGS. 2-7 . 
           [0017]      FIG. 9  is a top plan view of the first slide element shown in  FIG. 8 . 
           [0018]      FIG. 10  is a bottom plan view of the first slide element. 
           [0019]      FIG. 11  is a sectional side elevation view of the first slide element mounted to the upper base. 
           [0020]      FIG. 12  is an isometric view of a second slide element. 
           [0021]      FIG. 13  is a top plan view of the second slide element. 
           [0022]      FIG. 14  is a side elevation view of the second slide element. 
           [0023]      FIG. 15  is a front elevation view of the second slide element. 
           [0024]      FIG. 16  is a bottom plan view of the second slide element. 
           [0025]      FIGS. 17A-17C  are bottom views of the armrest rotation. 
       
    
    
       [0026]    While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION 
       [0027]    While the present invention is open to various modifications and alternative constructions, the preferred embodiment shown in the various figures of the drawing will be described herein in detail. It is understood, however, that there is no intention to limit the invention to the particular embodiment, form or example which is disclosed here. On the contrary, the intention is to cover all modifications, equivalent structures and methods, and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims, pursuant to 35 U.S.C. §112 (second paragraph). 
         [0028]    Referring now to  FIG. 1 , there is shown an office chair  10  having adjustable armrests. The chair includes a base  12 , a pedestal  14 , a frame assembly  16 , a seat assembly  18 , a back assembly  20 , a pair of adjustable armrests  22 ,  24  and control levers, such as a control lever  26 . 
         [0029]    The simplicity of the adjustable armrests may be appreciated by referring to  FIGS. 2 ,  3 ,  4  and  5 . The armrest  22  includes a support tube  30  connected to the frame assembly  16 , a mounting member in the form of a vertical adjustment slide  32 , a notched plate  34 , an operating rod  36 , a lock block  38  and a spring  40 . The vertical adjustment slide acts as a mounting member and is formed with an upper base  42 . Slidably mounted to the upper base  42  is a first or lower slide element  44 . Slidably mounted to the lower slide element  44  is a second or upper slide element  46  and attached to the upper slide element  46  is an armrest cover  48 . 
         [0030]    Reference is made to patents and patent publications assigned to the same assignee as the present application and entitled Vertically Adjustable Chair Armrest, U.S. Pat. No. 6,974,189; Chair with Backward and Forward Passive Tilt Capabilities, U.S. Pat. No. 6,969,116; Chair Back, U.S. Patent Application Publication 20050146195; Chair with Adjustable Seat Depth, U.S. Pat. No. 6,994,400; and Chair with Tilt Lock Mechanism, U.S. Pat. No. 7,066,538. These patents and publications disclose other features of the chair. All applications just mentioned are incorporated herein by reference. It is to be appreciated that a chair armrest may be fixed vertically and only adjustable horizontally, or may be fixed horizontally and only adjustable vertically, or the horizontal adjustment assembly disclosed here may be used with a vertical adjustment assembly different from that disclosed in U.S. Pat. No. 6,974,189. 
         [0031]    The upper base  42  has an arcuate upper surface  50  ( FIGS. 5 ,  6  and  7 ) and two fastener receiving openings  52 ,  54 . In alternative embodiments, upper surface  50  is planar or substantially planar. Threaded inserts, not shown, may be molded into the base. Two elongated projections or guide rails  56 ,  58  are also formed in the upper surface  50 , the elongated projections being disposed parallel to a first direction that extends forwardly and rearwardly or longitudinally as symbolized by a double headed arrow  60 ,  FIG. 1 . 
         [0032]    Referring now to  FIGS. 8 ,  9  and  10 , the lower slide element  44  is an elongated molded element having rounded end portions  62 ,  64 , an upper surface  70  and a lower surface  72 . An elongated mounting slot  74  extending in the longitudinal direction has two end portions  76 ,  78 . Bordering the slot opening is a slot lower wall  79 , a shoulder  80  and a slot upper wall  82 . The lower surface  72  is arcuate in shape for generally nesting onto the upper surface  50  of the base  42 . In alternative embodiments, lower surface  72  is planar or substantially planar. The lower surface  72  of the lower slide element is generally textured but also includes two parallel smooth runways  84 ,  86  for moving over the projections  56 ,  58  of the upper base  42 . The upper surface  70  includes two curved projections or guide rails  88 ,  90  directed in an arcuate path which crosses the first direction. The arcuate path is symbolized by a double headed arrow  91  ( FIG. 1 ). While the guide rails  88 ,  90  are shown proximate the center of the lower slide element  44  along its longitudinal axis, the guide rails  88 ,  90  may alternatively be located more proximate the ends of the lower slide element  44  along its longitudinal axis. The lower slide element  44  also includes two fastener receiving openings  94 ,  96  to receive fasteners attaching the upper slide element  46 . Two projecting spacers  97 ,  98  are formed in the upper surface  70 , and these engage the upper slide element  46  and compensate for manufacturing tolerances to help provide a consistent sliding force on the upper slide element. The length of the slot  74  helps define the longitudinal adjustment travel of the lower slide element relative to the upper base  42 . 
         [0033]    A pair of fasteners  100 ,  102  ( FIGS. 2 ,  4 ,  8 ,  9 ,  10  and  11 ) are provided, each having a head  104 ,  106  and a stem  108 ,  110 . Assembled around the stems are springs  112 ,  114  and placed beneath the springs are a pair of washers  116 ,  118 . The fasteners are located so that the stems  108 ,  110  extend through the slot  74  of the lower slide element  44  and are received by and engaged with the fastener receiving opening  52 ,  54  of the upper base  42 . The washers slide along the shoulder  80  and support the springs between them and the heads of the fasteners. Each of the fastener stems includes a shoulder portion  119 ,  120 , ( FIG. 4 ) and a thread portion  121 ,  122 . The shoulder portions engage the lower slot wall  79  for guiding the sliding action of the lower slide element  44 . Each washer  116 ,  118  includes a side rim which engages the upper slot wall  82 , and also acts to guide the sliding action of the lower slide element  44 . 
         [0034]    The springs  112 ,  114  provide a biasing force against the washers  116 ,  118  which in turn bear against the shoulder  80 ,  FIG. 11  of the slot. This arrangement ensures that the lower slide element  44  is pressed against the upper base  42  with a consistent force to compensate for manufacturing tolerances and provides the force to generate sufficient friction between the lower slide element  44  and the upper base  42  to restrain the location of the lower slide element once a chair user has adjusted the position of the lower slide element. Thus, flexibility is built into the manufacturing process of parts for the chair. 
         [0035]    The upper slide element  46  ( FIGS. 12 and 16 ) is in the shape of a longitudinally arcuate panel with curved end portions  130 ,  132 . The upper slide element  46  may alternatively be in the shape of a substantially planar longitudinal panel. The upper slide element  46  includes two arcuate lateral slots  134 ,  136  (extending along the arcuate path) each having closed ends  138 ,  140  and  142 ,  144 . As used herein, “arcuate” is defined as any curved shape having either a constant or changing radius of curvature along its contour. The upper slide element  46  includes shoulders  150 ,  151  around the slots, lower slot walls  152 ,  153  and upper slot walls  154 ,  156 . In a lower surface  158  of the upper slide element, a pair of arcuate recesses  160 ,  162  are formed to receive and engage the guide rails  88 ,  90  of the lower slide element. While the arcuate recesses  160 ,  162  are shown near the center of the upper slide element  46  along its longitudinal axis, the arcuate recesses  160 ,  162  may alternatively be located more proximate the ends of the upper slide element  46  along its longitudinal axis. Fastener openings  164 ,  166 ,  168 ,  170  are formed in the end portions and are used to receive fasteners to fasten the upper slide element to the armrest cover  48 . 
         [0036]    Another pair of fasteners  180 ,  182 , ( FIGS. 2 ,  12 , and  16 ) are provided, each having a head  184 ,  186 , ( FIG. 2 ) and a stem  188 ,  190 . Assembled around the stems are springs  192 ,  194  and placed beneath the springs are a pair of washers  196 ,  198 . The fasteners are placed so that the stems extend through the slots  134 ,  136  of the upper slide element  46  and are received by and engaged with the fastener receiving opening  94 ,  96  of the lower slide element  44 . The washers ride on the shoulders  150 ,  152  and support the springs between them and the heads of the fasteners. Each washer includes a peripheral rim  154 ,  156 . The arcuate recesses  160 ,  162  guide sliding movement of the upper slide element  48  when the recesses engage the guide rails  88 ,  90  of the lower slide element  44 . 
         [0037]    The springs  192 ,  194  provide a biasing force against the washers which in turn bear against the shoulders  150 ,  152 , and compensate for manufacturing tolerances. This arrangement also ensures that the upper slide element is pressed against the lower slide element with sufficient force to provide a needed friction force to restrain the location of the upper slide element once a chair user has adjusted the position of the upper slide element. 
         [0038]    A set of four fasteners  200 ,  202 ,  204 ,  206 , ( FIGS. 2 and 3 ) are provided to be received by the fastener openings  164 ,  166 ,  168 ,  170 ,  FIG. 13 , of the upper slide element and engage the cover  48 . 
         [0039]    The mounting member and upper base, the lower slide element and the upper slide member may be formed of a suitable synthetic resin, such as nylon. 
         [0040]    The adjustable armrest is very easy to assemble and allows assembly to be quickly accomplished. The lower slide element  44  is connected to the upper base  42  of the vertical slide  32  using the two fasteners  100 ,  102 . The arcuate recesses  160 ,  162  of the upper slide element are aligned with the guide rails  88 ,  90  of the lower slide element and the fasteners  180 ,  182  fit through the slots  134 ,  136  and are received in the openings  94 ,  96 . The upper slide element  46  is connected to the armrest cover  48  by using the fasteners  200 ,  202 ,  204 ,  206 , ( FIGS. 2 and 3 ). 
         [0041]    In operation, the lower slide element  44  is able to slide longitudinally (first direction) relative to the upper base  42  along the elongated slot  74 . In a similar manner, the upper slide element  46  rotates in along the arcuate path relative to the lower slide element  44  within the length of the arcuate slots  134  and  136 . The rotation may be about a fixed point that is aft of the arm rest such that arm rest motion tracks with rotation of the forearm and hand about the elbow or shoulder of the user. 
         [0042]      FIGS. 17A-C  show the armrest in three different rotational positions. In  FIG. 17A , the armrest  22  is shown at one terminal position as lower slide moves in an arcuate path relative to upper slide element  46 . In this configuration, first end  210  of the lower slide element  44  is located nearer to a first edge  212  of upper slide element than is second end  214 . In  FIG. 17B , the lower slide element  44  is shown having moved through an arcuate path to a mid position between first edge  212  and second edge  216 . In  FIG. 17C , the lower slide element  44  is shown having moved through an arcuate path to a second terminal position so that first end  210  of lower slide element  44  is closer to second edge  216  than is second end  214 . 
         [0043]    It can now be appreciated that within the parameters of this movement, the armrests of the office chair may be adjusted longitudinally and rotationally to any position within the limits of movement. Moreover, this is done with a simply constructed, relatively inexpensive structure which structure is reliable and robust. 
         [0044]    In summary, the present invention relates to an adjustable armrest for a chair comprising a mounting member connected to the chair, the member having an upper base, first and second slide elements mounted to the base, the first slide element being movable in a fore and aft direction while the second slide element causes rotation of the arm rest about a point such that the rotational motion of the arm rest roughly matches rotation of an arm around an elbow or shoulder. Each slide element has a slot and including fasteners positioned in the slots. 
         [0045]    There are a number of advantages, features and objects achieved with the present invention. For example, one advantage is that the present invention provides for an adjustable chair armrest which is movable in fore and aft directions and is rotatable about a point thereby providing a wide range of adjustability. Another advantage of the present invention are that the adjustable armrest disclosed here is that motion of the arm tracks with rotation of the forearm and hand about the elbow or shoulder of the user. Further advantages of the present invention are that the adjustable armrest is reliable and robust. Still other features of the adjustable armrest disclosed here is that it is simply constructed, relatively inexpensive, and easy to use. 
         [0046]    Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof. For example, altering the shapes of the lower slide element, the upper slide element, the upper base or the armrest cover will still be considered equivalent structures and will also come within the literal language of the claims. The same is true of the fasteners, the springs and the washers. Still other alternatives will also be equivalent as will many new technologies. There is no desire or intention here to limit in any way the application of the doctrine of equivalents nor to limit or restrict the scope of the invention.