Abstract:
An adjustment mechanism for a chair includes a housing and an adjustment element that is movable relative to the housing into a selectable one of at least two adjustment positions. Preferably, when assembled to a chair, the housing, possibly along with other elements of the chair, such as the armrest, completely encloses interlocking adjustment surfaces of the adjustment mechanism with the exception of a guide slot of the housing through which movement of the adjustment element is permitted between the at least two adjustment positions. The guide slot has a maximum width dimension sufficiently small to inhibit or prevent foreign objects from coming into contact with the interlocking adjustment surfaces of the adjustment mechanism.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to adjustment mechanisms for adjustable or foldable chairs, or other adjustable items. 
         [0003]    2. Description of the Related Art 
         [0004]    Adjustment mechanisms for adjustable or foldable chairs permit a portion of the chair to be positioned in a selected one of a number of different positions, or may simply permit the chair to be folded into a collapsed position. Such adjustment mechanisms need to be reliable in operation, provide ease of adjustment, permit relatively flat folding of the chair, and be relatively inexpensive to manufacture and easy to assemble. Prior art adjustment mechanisms that meet many or all of the desirable design characteristics described above, often expose the interlocking engagement surfaces of the mechanism, which can create a pinch hazard during folding, unfolding or adjustment of the chair. 
       SUMMARY OF THE INVENTION 
       [0005]    A need exists for adjustment mechanisms for chairs, or other objects, which meet a significant number of the desirable design characteristics and also provide improved shielding of the interlocking surfaces or components of the adjustment mechanism. In some embodiments, the present adjustment mechanisms provide improved pinch protection while also allowing a flat configuration upon folding, ease of adjustment, and relatively inexpensive and easy manufacture and/or assembly. 
         [0006]    A preferred embodiment involves an adjustment mechanism for a chair, including a housing having a forward wall, a rearward wall and a pair of side walls extending between the forward wall and the rearward wall. The forward wall, rearward wall and side walls cooperate to define an interior space and a bottom wall substantially closes a lower end of the interior space, preferably with the exception of guide slot extends through the bottom wall in a longitudinal direction along the housing. At least a first adjustment surface and a second adjustment surface are provided, each of which extend in a lateral direction within the interior space. The first adjustment surface and the second adjustment surface are spaced from one another in the longitudinal direction. An adjustment arm, the adjustment arm extends through the guide slot and has a first portion within the interior space of the housing and a second portion outside of the interior space. The first portion of the adjustment arm defines an engagement surface configured for selective engagement with one of the first and second adjustment surfaces. The first portion further comprises a retention element that defines a retention surface, which contacts the bottom wall to limit downward movement of the adjustment arm and prevent disengagement of the adjustment arm from the housing. The second portion of the adjustment arm defines an attachment portion that is configured to be attachable to a component of the chair. The adjustment arm is movable between a first vertical position and a second vertical position relative to the housing, wherein in the first vertical position the adjustment arm is able to move in the longitudinal direction from one side of the first adjustment surface to the other side of the first adjustment surface and in the second vertical position the engagement surface of the adjustment arm is able to engage either one of the first and second adjustment surfaces to selectively adjust a longitudinal position of the engagement arm relative to the housing. 
         [0007]    In some arrangements of the adjustment mechanism, the first adjustment surface is defined by a first adjustment pin supported relative to the housing and the second adjustment surface is defined by a second adjustment pin supported relative to the housing. A third adjustment surface, fourth adjustment surface, fifth adjustment surface or additional adjustment surfaces can be provided. Preferably, the adjustment arm is capable of passing from one side to the other side of a sufficient number of the provided adjustment surfaces to permit the adjustment arm to engage each of the provided adjustment surfaces. In some arrangements, the retention element is a retention pin that is offset from the engagement surface in a lateral direction. 
         [0008]    Preferably, in some embodiments, a maximum width of the first portion of the adjustment arm defines a first longitudinal dimension and a distance between the first and second adjustment surfaces defines a second longitudinal dimension, wherein the first longitudinal dimension is greater than the second longitudinal dimension such that the first portion of the adjustment arm cannot move upward through a space between the first and second adjustment surfaces. In some embodiments, the first portion of the adjustment arm includes a ledge defining a guide surface that extends in a longitudinal direction from the engagement surface. The ledge is configured to contact a closest one of the first and second adjustment surfaces when the adjustment arm is moved from the first position toward the second position to guide the adjustment surface toward the engagement surface. 
         [0009]    In some arrangements, the housing can include an access opening that extends in a lateral direction from the guide slot and passes through the bottom wall. The access opening is configured to permit the retention element to pass through the access opening. In a first angular orientation of the adjustment arm relative to the housing, the first portion of the adjustment arm is sized and shaped such that the retention element can move from the interior space into the access opening, thereby permitting removal of the first portion of the adjustment arm from the interior space through the guide slot. In a second angular orientation of the adjustment arm, one or more of the walls and the adjustment surfaces interferes with movement of the first portion of the adjustment arm such that the retention element is prevented from entering the access opening. 
         [0010]    In some arrangements, a rearward portion of the guide slot passes through a portion of the rear wall of the housing and is configured to receive a portion of the adjustment arm such that the adjustment arm can be angled relative to the housing into a collapsed orientation. Preferably, a width of the guide slot is substantially equal to a thickness of the adjustment arm such that no substantial gap exists in a lateral direction between the adjustment arm and a surface of the bottom wall that defines the guide slot. In some embodiments, the width of the guide slot is less than about 6 millimeters. 
         [0011]    An embodiment involves an adjustment mechanism for a chair. The adjustment mechanism can include a housing having a side wall portion defining a perimeter of an interior space of the housing, a bottom wall that substantially closes a lower end of the interior space, a guide slot that extends through the bottom wall in a longitudinal direction along the housing, and at least a first adjustment surface and a second adjustment surface, each of which extend in a lateral direction within the interior space. The first adjustment surface and the second adjustment surface are spaced from one another in the longitudinal direction. An adjustment arm extends through the guide slot and has a first portion within the interior space of the housing and a second portion outside of the interior space. The first portion of the adjustment arm defines an engagement surface configured for selective engagement with one of the first and second adjustment surfaces and the second portion of the adjustment arm defines an attachment portion that is configured to be attachable to a component of the chair. The adjustment arm is movable between a first vertical position and a second vertical position relative to the housing. In the first vertical position, the adjustment arm is able to move in the longitudinal direction from one side of the first adjustment surface to the other side of the first adjustment surface and, in the second vertical position, the engagement surface of the adjustment arm is able to engage either one of the first and second adjustment surfaces to selectively adjust a longitudinal position of the engagement arm relative to the housing. The guide slot has a maximum width dimension of less than about 6 millimeters and the adjustment arm has a thickness that is substantially equal to the maximum width dimension of the guide slot such that no substantial gap is created in a lateral direction between the adjustment arm and a surface of the housing that defines the guide slot. 
         [0012]    In some arrangements, the first adjustment surface is defined by a first adjustment pin supported relative to the housing and the second adjustment surface is defined by a second adjustment pin supported relative to the housing. In some arrangements, the first portion of the adjustment arm defines a maximum longitudinal dimension that is sufficient to prevent the first portion of the adjustment arm from moving entirely through a space between the first and second adjustment surfaces. In some arrangements, the first portion of the adjustment arm includes a ledge defining a guide surface extending in a longitudinal direction from the engagement surface. The ledge is configured to contact a closest one of the first and second adjustment surfaces when the adjustment arm is moved from the first position toward the second position to guide the adjustment surface toward the engagement surface. A rearward portion of the guide slot can pass through a rearward portion of the side wall of the housing and receive a portion of the adjustment arm when the adjustment arm is angled relative to the housing in a collapsed orientation. 
         [0013]    An embodiment involves an adjustable chair having a stationary portion and an adjustable portion that is adjustable relative to the stationary portion. The stationary portion includes a frame portion and the adjustable portion includes a backrest portion and an armrest portion. The chair includes an adjustment mechanism that permits adjustment of the adjustable portion into a selected one of at least two adjustment positions. The adjustment mechanism includes a housing that is coupled to one of the stationary portion and the adjustable portion. An adjustment member is coupled to the other of the stationary portion and the adjustable portion. The housing defines a guide slot through which the adjustment member can move relative to the housing between the at least two adjustment positions. The adjustment member has a first position relative to the housing in which the adjustment member can move relative to the housing and a second position relative to the housing in which the adjustment member can be locked in the selected one of the at least two adjustment positions. In the second position, respective engagement surfaces of the adjustment member and the housing contact one another to inhibit relative movement of the adjustment member and the housing to secure the adjustment member into the selected one of the at least to adjustment positions. The housing, along with the one of the stationary portion and the adjustable portion to which the housing is coupled, completely encloses the engagement surfaces of the adjustment member and the housing with the exception of the guide slot. 
         [0014]    In some arrangements of the chair, the guide slot has a maximum width dimension of less than about 6 millimeters. In other arrangements, the guide slot can have a maximum width dimension of about 4 millimeters. The adjustment member can be movable to an angled orientation relative to the housing which permits the adjustment member to be inserted into and removed from the housing, wherein the adjustment member is restrained from moving to the angled orientation when assembled to the chair. 
         [0015]    Embodiments also include methods of manufacturing the adjustment mechanisms and/or chairs or other objects incorporating one or more adjustment mechanisms. The manufacturing process can include positioning the adjustment element or arm in a first angular orientation relative to the housing to permit the adjustment element to be inserted through the guide slot. The adjustment element can then be coupled to a component of the chair or other object, which can restrain the adjustment element from exiting the guide slot by contacting portions of the housing, chair or other object, and/or by inhibiting or preventing rotation of the adjustment element to the first position after assembly. Methods of manufacturing can include assembling the adjustment element or arm into the housing, and then assembling one or more of the components that define the adjustment surfaces to the housing, the one or more components then inhibiting or preventing removal of the adjustment element from the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    These and other features, aspects and advantages of the present chair adjustment mechanism are described herein with reference to drawings of preferred embodiments, which are provided for the purpose of illustration and not for limitation. The drawings contain seventeen (17) figures. 
           [0017]      FIG. 1  is a perspective view of an adjustable chair including a pair of adjustment mechanisms having certain features, aspects and advantages of the present invention. 
           [0018]      FIG. 2  is an enlarged perspective view of a portion of the adjustable chair of  FIG. 1  illustrating one of the adjustment mechanisms interconnecting an arm and a pair of legs of the chair. 
           [0019]      FIG. 3  is a side view of a portion of the adjustable chair of  FIG. 1  illustrating one of the adjustment mechanisms in a folded configuration of the chair. 
           [0020]      FIG. 4  is a partial front view of the adjustment mechanism of  FIG. 3  in the folded configuration of the chair. 
           [0021]      FIG. 5  is a side view of an adjustment arm removed from the adjustment mechanism. 
           [0022]      FIG. 6  is a rear view of the adjustment arm of  FIG. 5 . 
           [0023]      FIG. 7  is a side view of an adjustment case of the adjustment mechanism. 
           [0024]      FIG. 8  is a top view of the adjustment case of  FIG. 7 . 
           [0025]      FIG. 9  is a bottom view of the adjustment case of  FIG. 7 . 
           [0026]      FIG. 10  is a rear view of the adjustment case of  FIG. 7 . 
           [0027]      FIG. 11  is a cross-sectional view of the adjustment mechanism taken along line  11 - 11  of  FIG. 8  including the adjustment arm being introduced into the adjustment case. 
           [0028]      FIG. 12  is a cross-section view of the adjustment mechanism similar to  FIG. 11 , with the adjustment arm in one of several selectable positions. The adjustment arm is shown in another selectable position in dashed lines. 
           [0029]      FIG. 13  is a cross-sectional view of the adjustment mechanism similar to  FIG. 11 , with the adjustment arm in a position in which it can move between the several selectable positions. 
           [0030]      FIG. 14  is a side view of a modification of the adjustment case of an alternative adjustment mechanism, which has a greater number of selectable positions compared to the adjustment case of  FIGS. 7-10 . 
           [0031]      FIG. 15  is a top view of the adjustment case of  FIG. 14 . 
           [0032]      FIG. 16  is a bottom view of the adjustment case of  FIG. 14 . 
           [0033]      FIG. 17  is a rear view of the adjustment case of  FIG. 14 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0034]    The adjustment mechanisms disclosed herein are well-suited for use in an adjustable chair to permit adjustment of a position of one portion of the chair relative to another portion of the chair. In the illustrated arrangements, the chair is foldable or collapsible and the adjustment mechanism permits an arm of the chair to be adjusted relative to a frame of the chair. Preferably, adjustment of the arm of the chair adjusts a recline position of a back of the chair. In addition, preferably, an adjustment mechanism is provided on each of the arms of the chair. However, the adjustment mechanism can be used to permit adjustment of other features of a chair and/or can be provided in other locations or between other portions of the chair. Moreover, the adjustment mechanism may find utility in a variety of other applications to permit adjustment of one structural element relative to another structural element. 
         [0035]    The adjustment mechanisms are disclosed herein in the context of an adjustable or foldable chair, which can be unfolded and positioned on a surface. The chair can also be folded into a generally flat configuration. The adjustment mechanisms are often described herein using relative terms, such as forward, rearward, above, below, upper, lower, left and right. These terms are used for convenience and usually in the context of the specific figure(s) being described, unless otherwise noted or apparent from the context. 
         [0036]      FIG. 1  illustrates a foldable, adjustable chair  20  that includes at least one adjustment mechanism  22 . The illustrated chair  20  includes a pair of adjustment mechanisms  22  on each side of the chair  20 . The adjustment mechanism  22  permits adjustment of one component or portion of the chair  20  relative to another component or portion of the chair  20 . The illustrated chair  20  includes a frame  24  and a pair of armrests or arms  26  supported by or relative to the frame  24  and extending in a fore-aft direction on each side of the chair  20 . The frame  24  can include a seat frame portion  28  and a backrest or back frame portion  30 . The seat frame portion  28  can support or define a seat portion  32  of the chair  20  and the back frame portion  30  can support or define a backrest  34  of the chair  20 . The seat frame portion  28 , seat portion  32 , back frame portion  30  and backrest  34  can be of any suitable construction. For example, each one or a combination of several of these components can be constructed of a unitary piece of material. In other arrangements, the frame portions  28 ,  30  can be of a rigid material (e.g., metal or plastic, rod or tubular) construction and the seat  32  and backrest  34  can be constructed of a fabric (or other suitable material) panel or plurality of panels or strips that extend between or are supported by the frame portions  28 ,  30 . 
         [0037]    The frame  24  preferably also includes at least one front leg portion  36  and at least one rear leg portion  38 . The front leg portion  36  and rear leg portion  38  can be of any suitable construction. For example, one or both of the front leg portion  36  and rear leg portion  38  can include multiple legs. That is, the chair  20  can include two (or more) front legs and two (or more) rear legs, which may or may not be coupled to one another. However, in the illustrated arrangement, the front leg portion  36  includes a generally U-shaped frame portion, and can include one or more cross supports  40 . Similarly, the illustrated rear leg portion  38  includes a generally U-shaped frame portion, and can include optional cross supports (not shown). The front leg portion  36  and rear leg portion  38  support the seat frame portion  28 , seat portion  32 , back frame portion  30  and backrest  34 . 
         [0038]    In addition, the front leg portion  36  and the rear leg portion  38  preferably are pivotally coupled to one another at or near their upper ends (free ends of the U-shaped frame portions). Accordingly, the front leg portion  36  and the rear leg portion  38  can fold relative to one another. Preferably, the front leg portion  36  and the rear leg portion  38  can fold one inside the other such that the frame portions are positioned side-by-side in a lateral direction, thereby minimizing the thickness of the folded leg portions  36 ,  38  in the folded configuration. In the illustrated arrangement, the front leg portion  36  has a smaller lateral dimension than the rear leg portion  38  so that the front leg portion  36  is positioned within the rear leg portion  38 . However, this orientation could also be reversed. Furthermore, preferably the seat portion  32  and backrest  34  are pivotally connected and can fold relative to one another so that the entire chair  20  can fold in a manner well known to those in the art. 
         [0039]      FIG. 2  illustrated one embodiment of an adjustment mechanism  22 , which adjustably connects the front and rear leg portions  36 ,  38  to one of the arms  26 .  FIG. 2  illustrates the right side adjustment mechanism  22 . However, the left side adjustment mechanism  22  preferably is identical to or a mirror image of the right side adjustment mechanism  22  and, thus, is not separately described herein. Preferably, the adjustment mechanism  22  is coupled to a downwardly-facing surface of the arm  26  by any suitable method or mechanism, such as by a plurality of fasteners  42 . The adjustment mechanism  22  permits the arm  26  to move to any selected one of a plurality of possible adjustment positions. The illustrated adjustment mechanism  22  includes three adjustment positions; however, a lesser or greater number of adjustment positions can be provided. In addition, it is possible to have an adjustment mechanism with a single position (in an unfolded orientation of the chair  20 ), which is operable to permit simple movement between a folded position and a single unfolded position. In the illustrated arrangement, adjustment of the arms  26  of the chair  20  results in angular adjustment of the backrest  34 . Accordingly, the illustrated adjustment mechanism(s)  22  can be referred to herein as backrest  34  reclining adjustment mechanisms. 
         [0040]    The adjustment mechanism  22  can include a housing, which is referred to herein as a tracking body or tracking case  44 , and an adjustment element, which is referred to herein as a tracking or adjustment arm  46 . The adjustment arm  46  is movable relative to the case  44  and can be secured in one of the adjustment positions relative to the case  44 . Thus, the adjustment arm  46  operates in a manner similar to and can be referred to as a “pawl” or “follower” and the tracking case  44  operates in a manner similar to and can be referred to as a “cam”. In the illustrated mechanism  22 , the adjustment positions are defined by engagement, adjustment or stop surfaces that can be engaged by the arm  46 . The engagement surfaces can each be defined by a portion of an adjustment element, such as an adjustment pin  48 , which can be supported by the case  44  and can be defined by any suitable structure, such as a rivet, screw, bolt, pin, etc. The engagement surfaces can also be defined by an integral or unitary portion of the case  44 . The adjustment pins  48  extend in a lateral direction through the case  44 . The case  44  is of an elongate, generally hollow construction. A slot  50  extends lengthwise along a bottom of the case  44  and the arm  46  passes through the slot  50  such that a portion of the arm  46  is positionable within the hollow interior of the case  44  and a portion of the arm  46  is outside of the case  44 . The arm  46  can move within the slot  50  in a fore-aft direction relative to the case  44  to any desired one of the adjustment positions and be engaged with an adjustment pin  48 , as described further below with reference to  FIGS. 11-13 . 
         [0041]    With reference to  FIGS. 3 and 4 , advantageously, the illustrated adjustment mechanism  22  permits folding of the chair  20  into a relatively thin configuration. Preferably, in the folded configuration, as described above, the front leg portion  36  and rear leg portion  38  are positioned side-by-side in the lateral direction. Preferably, the front leg portion  36  is positioned on one (e.g., inner or inboard) side of the adjustment arm  46  and the rear leg portion  38  is positioned on an opposite (e.g., outer or outboard) side of the arm  46 . Preferably, a pivot  52  extends through the front leg portion  36 , the adjustment arm  46  and the rear leg portion  38 . The pivot  52  can be of any suitable construction, such as a rivet, bolt or pin. Preferably, the adjustment arm  46  is fixed for movement with one of the legs  36 ,  38  and is rotatable with respect to the other leg  36 ,  38 . In the illustrated arrangement, the arm  46  is fixed to the front leg portion  36 , such as by a fastener  54  (e.g., rivet, bolt or pin), which is spaced from and is a secondary fastener along with pivot  52 . 
         [0042]    As shown in  FIG. 3 , when the leg portions  36 ,  38  are in a folded configuration relative to each other and the armrest  26 , an axis A of the leg(s)  36 ,  38  is generally parallel with an adjacent surface of the armrest  26  or with the armrest  26  in general. In the folded configuration, preferably, the adjustment arm  46  extends through a portion of the slot  50  defined in a rear surface of the tracking case  44 , which facilitates the folding of the chair  20  into a relatively thin configuration. Advantageously, the nesting of the leg portions  36 ,  38  and general alignment of the leg portions  36 ,  38  and the armrest  26  allows the chair  20  to be relatively thin in the folded configuration, which allows a greater number of chairs  20  to be placed in a container or other packaging relative to other foldable chair designs thereby reducing shipping costs and the resulting cost of the chair  20  to the consumer. 
         [0043]      FIGS. 5 and 6  illustrate an embodiment of the adjustment arm  46  separate from the case  44 . The illustrated arm  46  is a relatively thin, plate-like member, with an upper hook-like portion. The arm  46  defines a thickness T in a lateral direction (relative to the chair  20  when assembled), which preferably is slightly smaller than a width W of the slot  50  ( FIG. 8 ). Accordingly, a gap between either side of the arm  46  and the surfaces of the case  44  defining the slot  50  is small and reduces the risk of an object, such as a person&#39;s finger, other body part, article of clothing or other item, from getting pinched between the arm  46  and the case  44 . Moreover, preferably, the width W of the slot  50  is relatively small to reduce the risk of an object, such as the aforementioned objects, from entering the slot  50 . Preferably, the width of the slot  50  is substantially smaller than a width of the bottom wall of the case  44 . For example, the width W of the slot  50  can be between about 2 and about 10 millimeters, between about 3 and about 6 millimeters, or can be about 4 millimeters. The slot  50  can be less than about 10 millimeters, less than about 8 millimeters, less than about 6 millimeters, or equal to or less than about 4 millimeters. Preferably, the thickness T of the arm  46  can be a corresponding size that preferably minimizes a gap between the arm  46  and the case  44 , while permitting free and smooth movement of the arm  46  back and forth within the slot  50 . 
         [0044]    The hook-like upper portion of the arm  46  defines an engagement surface  56  that is capable of engaging an engagement surface or portion of one of the adjustment pins  48 . Preferably, the engagement surface  56  generally conforms to the shape of the engagement surfaces of the adjustment pins  48 . In the illustrated arrangement, the engagement surface  56  is rounded or curved and generally corresponds to a size or diameter of the adjustment pins  48 . A ledge portion  58  extends forward from the engagement surface  56 . The ledge  58  can contact an adjustment pin  48  to limit upward movement of the arm  46  relative to the case  44 . In addition, the upper portion of the arm  46  defines a width W that preferably is greater than a gap distance D between the adjustment pins  48  ( FIG. 11 ) to prevent the upper portion of the arm  46  from passing between an adjacent pair of the pins  48 , thereby ensuring that the ledge  58  or the engagement surface  56  contacts one of the adjustment pins  48  regardless of where the arm  46  is positioned within the length of the slot  50 . 
         [0045]    The adjustment arm  46  preferably also includes a retention element configured to retain the adjustment arm within the case  44 . The illustrated retention element is a restrictor pin  60 , which extends laterally outward from a side surface of the arm  46 . The restrictor pin  60  cannot pass through the slot  50  and, thus, prohibits disengagement of the arm  46  and the case  44 . That is, the restrictor pin  60  operates as a restriction mechanism. As described below, the hollow interior of the case  44  defines a space configured to accommodate the restrictor pin  60  during movement of the arm  46  within the slot  50 . The illustrated adjustment arm  46  also includes a pair of openings  62 , which pass laterally through the arm  46  and accommodate the pivot  52  and fastener  54  ( FIG. 4 ). The openings  62  are aligned and vertically-spaced from one another. 
         [0046]      FIGS. 7-10  illustrate an embodiment of the tracking case  44 . The illustrated case  44  is elongate and generally rectangular in side plan view and generally T-shaped when viewed from the front or rear. Thus, the case  44  includes a lower body portion  64  and an upper flange portion  66  that is wider in a lateral direction than the body portion  64 . The case  44  can include bosses  68  in one or both side surfaces, each of which surrounds one of the openings  70  that support the adjustment pins  48 . In the illustrated case  44 , at least one, and preferably a plurality of openings  72  extend in a vertical direction through the flange portion  66  to accommodate the fasteners  42  that secure the adjustment mechanism  22  to the armrests  26  of the chair  20 . Preferably, the openings  72  are spaced along each side of the flange portion  66 . Six openings  72 , three on each side, are provided in the illustrated case  44 . 
         [0047]    The slot  50  preferably extends completely through the case  44  in the vertical direction. When the case  44  is coupled to the armrest  26  of the chair  20 , the lower surface of the armrest  26  closes an upper end of the slot  50  and acts as a stop surface to prevent the adjustment arm  46  from exiting an upper end of the slot  50 . With reference to  FIG. 10 , a portion  50   a  of the slot  50  extends through the rear surface of the case  44 . Preferably, the portion  50   a  extends upwardly from a lower surface of the case  44  to an intermediate location on the body portion  64  of the case  44 . The portion  50   a  accommodates a portion of the adjustment arm  46  when the leg portions  36 ,  38  and/or the chair  20  are in a folded configuration ( FIG. 3 ). The slot  50  preferably also includes a portion  50   b  that extends laterally from the remainder of the slot  50  and is configured to accommodate the restrictor pin  60  and permit the adjustment arm  46  to be introduced through a lower end of the slot  50  during initial assembly of the adjustment mechanism  22 . 
         [0048]      FIG. 11  is a cross-sectional view of the adjustment mechanism  22  during initial assembly of the adjustment arm  46  into the case  44 . The upper hook-like portion of the arm  46  preferably is sized and shaped to permit the arm  46  to pass through the slot  50  when the arm  46  is angled relative to the case  44 . In particular, a distance between the restrictor pin  60  and an upper most surface portion of the arm  46  is sized to permit the restrictor pin  50  to pass through the portion  50   b  of the slot and clear the forward-most pin  48  when the arm  46  is sufficiently angled relative to the case  44 , as illustrated. In some arrangements, the arm  46  must be inserted into the slot  50  prior to one or both of the leg portions  36 ,  38  being assembled to the arm  46  because the presence of one or both legs  36 ,  38  would interfere with the case  44  and prevent the arm  46  from being angled sufficiently to clear the forward-most pin  48 . However, in other arrangements, the arm  46  can be inserted into the slot  50  before the forward-most pin  48  is assembled to the case  44 . In such an arrangement, the leg portions  36 ,  38  may be assembled to the arm  46  prior to insertion of the arm  46  into the slot  50  because it may not be necessary to rotate the arm  46 . Moreover, depending on the geometry of the slot  50 , the location of the portion  50   b , the size, number and/or location of the pin(s)  48 , it may be necessary or desirable to insert the arm  46  into the slot  50  prior to assembly of pin(s)  48  in addition to or other than the forward-most pin  48  to the case  44 . Thus, arm  46  may be inserted into the slot  50  prior to assembly of the any or all of the rearward-most pin  48  or one or more intermediate pins  48  during initial assembly of the adjustment mechanism  22 . 
         [0049]      FIG. 12  illustrates the arm  46  in one of the possible adjustment positions relative to the case  44 . A second position is illustrated with the arm  46  in dashed lines. In the illustrated arrangement, a third intermediate position is possible between the illustrated positions when the arm  46  is in engagement with the center adjustment pin  48 . As described above, the engagement surface  56  of the arm  46  contacts or engages the engagement pin  48  to secure the arm  46  in a desired one of the possible adjustment positions. In the illustrated arrangement, the structure of the leg portions  36 ,  38  of the chair  20  maintains the front leg portion  36 , or at least an upper end portion of the leg  36 , in a generally consistent rotational position relative to the case  44 , such as a generally vertical direction and, thus, the arm  46  in a generally consistent (e.g., vertical) rotational position when the chair  20  is on a generally horizontal surface. As described above, the width W of the upper portion of the arm  46  is sized such that it cannot pass between the pins  48  and the combination of the rounded upper edge surface of the arm  46  rearward of the engagement surface  56  and the ledge  58  ensure that the arm  46  moves into engagement with one of the pins  48  when the armrest  26  is moved downward with respect to the front leg portion  36  (and, thus, the case  44  is moved downward with respect to the arm  46 ). Thus, reliable positioning and adjustment of the adjustment mechanism  22  is ensured. 
         [0050]      FIG. 13  illustrates the arm  46  in a position relative to the case  44  wherein the arm  46  can move between adjustment positions. In other words, the arm  46  is capable of passing from one side to another of at least the adjustment pins  48  other than the forward-most pin  48 . The restrictor pin  60  contacts the case  44  to prevent the adjustment arm  46  from exiting the slot  50  and disengaging from the case  44 . In particular, the case  44  defines a secondary cavity portion  74  that is laterally offset, adjacent and communicating with the slot  50  and is aligned with or includes the portion  50   b  of the slot  50 . The cavity portion  74  accommodates the restrictor pin  60  throughout the movement of the arm  46  relative to the case  44 , and also limits at least downward and rearward movement of the arm  46 . 
         [0051]    Preferably, the cavity portion  74  includes a lower surface  76 , which contacts the restrictor pin  60  to limit downward movement of the arm  46  and prevent disengagement of the arm  46  from the case  44 . The cavity portion  74  also includes a rearward surface  78  that limits rearward movement of the arm  46 . Contact between the engagement surface  56  or ledge  58  can limit upward movement of the arm  46  and contact between the forward-most adjustment pin  48  and the engagement surface  56  can limit forward movement of the arm  46 . The cavity portion  74  can have a raised lower surface portion  80  surrounding the portion  50   b  of the slot  50 . The raised lower surface portion  80  contacts the restrictor pin  60  to force the arm  46  upward and into engagement with the forward-most pin  48  and prevent the restrictor pin  60  from passing through the portion  50   b  of the slot  50 , at least when the arm  46  is generally vertical. In one arrangement, the raised lower surface portion  80  is positioned below, and preferably slightly below, the bottom of the forward-most adjustment pin  48  or other adjustment pin  48  that is closest or adjacent the portion  50   b  that permits the restrictor pin  60  to exit the interior of the case  44 . The cavity portion  74  can include a transition surface  82  vertically between the lower surface  76  and the raised lower surface portion  80 . The transition surface  82  can be a flat surface, angled surface or curved surface or any other shape to contact the restrictor pin  60  and urge the arm  46  upwardly and into contact with the forward-most adjustment pin  48 . 
         [0052]    The adjustment mechanism  22  and its various components can be constructed of any suitable, preferably rigid, material. In a preferred arrangement, the case  44  is constructed of a plastic or composite material by any suitable manufacturing method, such as injection molding. The adjustment pins  48  and adjustment arm  46  preferably are constructed of a metal material to provide strength and wear resistance. However, other suitable materials and construction methods can be employed to manufacture any of the components of the adjustment mechanism  22 . 
         [0053]      FIGS. 14-17  illustrate an embodiment of a tracking case  44  of a tracking or adjustment mechanism  22 . The case  44  of  FIGS. 14-17  is substantially similar in many or most respects to the case  44  of  FIGS. 1-13 . Accordingly, the same reference numbers or characters are used to indicate the same or similar elements. The case  44  of  FIGS. 14-17  includes a greater number of openings  70  configured to support a greater number of adjustment pins  48  compared to the case  44  of  FIGS. 1-13 . Accordingly, an adjustment mechanism  22  constructed with the case  44  of  FIGS. 14-17  provides a greater number of possible adjustment positions compared to the adjustment mechanism  22  of  FIGS. 1-13 . The illustrated case  44  of  FIGS. 14-17  includes five adjustment positions. However, cases with four adjustment positions or six or more adjustment positions are also contemplated. The number of available adjustment positions can be selected based on the particular application for the adjustment mechanism, including whether the adjustment mechanism is intended for recline adjustment, some other adjustment of a chair or even a non-chair application. In other respects, the case  44  of  FIGS. 14-17  is substantially similar or the same in construction and/or operation as the case  44  described with reference to  FIGS. 1-13 . 
         [0054]    Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In particular, while the present chair adjustment mechanism has been described in the context of particularly preferred embodiments, the skilled artisan will appreciate, in view of the present disclosure, that certain advantages, features and aspects of the adjustment mechanism may be realized in a variety of other applications, many of which have been noted above. Additionally, it is contemplated that various aspects and features of the invention described can be practiced separately, combined together, or substituted for one another, and that a variety of combination and subcombinations of the features and aspects can be made and still fall within the scope of the invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims.