Abstract:
A shelf and swivel for supporting a shelf for rotation with respect to an underlying base, the shelf including an off-axis aperture, the swivel including a first member having a plurality of openings to receive fasteners for securing the swivel to the underlying base and a pair of downward projections straddling one of the openings. A second swivel member, coupled to the first swivel member for rotation about a vertical axis, is secured to a lower surface of the shelf so that the first member openings are serially accessible through the shelf aperture. A first fastener is installed through the shelf aperture and aligned first swivel member opening into the underlying base with sufficient force to embed the projections in the underlying base, thereby inhibiting movement of the first swivel member sufficiently to permit rotation of the shelf to serially expose additional first member openings to receive additional fasteners.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to swivel bases having a detent that can be used to pivotally support platforms, lazy susans and cabinets with at least one preferred stopping position. The present invention also relates to features facilitating the installation of such swivel bases. 
         [0003]    2. Description of the Prior Art 
         [0004]    There are presently available a number of support systems for pivotally supporting platforms, shelves and movable cabinets within an enclosure. For example, kitchen corner cabinets are often provided with one or more shelves that are supported for rotation as a unit so that the goods on the shelves can be more easily accessed. Typically the support mechanism includes at least one detent that can be used to define a “closed” position for the shelving unit. The detent-defined closed position can facilitate the positioning of doors or face mountings to ensure an enhanced appearance to the cabinet as a whole. The correct positioning of the detent defining mechanism in the cabinet is required to avoid any skewed appearance to the unit when in the “closed” position. 
         [0005]    A representative prior art support system for pivotally supporting a shelf within a cabinet is disclosed in U.S. Pat. No. 4,440,459. The support system includes a hub receptacle affixed to the bottom of a shelf unit. An adjustable hub is mounted on a plate attached to the floor of the cabinet. The hub is received within the hub receptacle projecting downwardly from the bottom shelf when the shelf is positioned within the cabinet. Detents are provided in the hub receptacle and followers project outward from the hub to engage the detents to assist in maintaining the rotary shelf unit in a desired detent defined position. Adjustment of the detent defined position is achieved by adjusting the angular position of the hub on the plate. Wheels attached to the bottom shelf ride on the plate and support the shelf unit. Through repeated engagement and disengagement of the detents and followers, the hub can become loosened so that the detent defined position is no longer accurate. 
         [0006]    A preferred support system would be a single pre-assembled unit that could be easily and quickly installed by a cabinet manufacturer. The preferred support system would be rugged enough to support any load that would reasonably be anticipated in a given installation. The preferred support system, once installed, would not be subject to loosening that could affect the desired detent defined position. 
       SUMMARY OF THE INVENTION 
       [0007]    A support system of the present invention includes a swivel that can have a first member including a plurality of openings to receive fasteners for securing the first member to an underlying base. The swivel can also include a second member that can be mounted to a lower surface of a shelf unit. The second member is pivotally connected to the first member and defines an axis of rotation for the shelf unit relative to the base. At least one projection projects from a lower surface of the first member for engagement with the underlying base to facilitate a secure alignment of the first member relative to the underlying base. An aperture can be provided in the shelf unit to facilitate the attachment of the first member to the underlying base. A plug can be inserted into the aperture following attachment of the first member to the underlying base. 
         [0008]    The swivel first member can include a race surface facing radially outward, while the swivel second member can include a race surface confronting the race surface of swivel first member. A plurality of low friction members can be positioned between the race surfaces of the swivel first and second members. The low friction members can take the form of balls, which can be made of metal such as steel or of a polymer such as nylon or polyoxymethylene (Delrin). The swivel first member can include a flange extending radially inward from a lower edge of the swivel first member race. The flange of the swivel first member can include the plurality of openings to receive fasteners for securing the first member to an underlying base. The swivel second member can include a support ridge obverse the second member race surface. The support ridge can include a plurality of channels and webs. Openings can be provided in the ridge to receive fasteners coupling the second member to a bottom surface of a shelf. 
         [0009]    The second member can have a contoured surface including at least one pair of adjacent lobes separated by an indentation defining a detent. One or more support plates can be coupled to the first member, each support plate supporting a follower and biasing means biasing the follower into contact with the second member contoured surface. The contoured surface can be a radially outwardly facing surface of the second member. The follower can take the form of an arm pivotally connected to the support plate so as to move perpendicular to the contoured surface. The follower can have a wedge surface suitable for insertion in the indentation between the pair of adjacent lobes. The biasing means can take the form of a compression spring situated between the wedge surface of the follower and an upstanding flange on the support plate. 
         [0010]    The support system swivel can be installed by securing the second member to a bottom surface of a shelf unit while a detent is engaged. The second member can be situated so that an axis of rotation defined by the second member race surface is aligned with a target axis of rotation of the shelf unit. The second member can also be situated so that one of the plurality of openings in the first member situated on an opposite side of the axis of rotation to the projection from the lower surface of the first member is aligned with an aperture in the shelf unit. The shelf unit can then situated in a cabinet at a desired location and orientation and a first fastener can be inserted through the aperture in the shelf unit to fasten the first member to the underlying base with sufficient force to ensure the projection located on the opposite side of the axis of rotation penetrates into the underlying base surface. The shelf unit can then be rotated on the swivel to disengage the follower from the detent to reveal through the shelf unit aperture additional openings in the first member, which can receive additional fasteners to secure the first member to the underlying base surface. 
         [0011]    Other features and advantages of the present invention will become apparent to those skilled in the art from the following disclosure of preferred embodiments of the present invention exemplifying the best mode of practicing the invention. The following disclosure references the accompanying drawings illustrating the preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a corner cabinet employing a swivel base to support a rotatable shelf. 
           [0013]      FIG. 2  is a perspective view of an upper surface of a shelf such as can be employed in the cabinet shown in  FIG. 1 . 
           [0014]      FIG. 3  is a perspective view of a lower surface of the shelf shown in  FIG. 2  including a swivel base. 
           [0015]      FIG. 4  is a perspective view of the upper surface of the swivel base shown in  FIG. 3 . 
           [0016]      FIG. 5  is a bottom plan view of the swivel base shown in  FIGS. 3 and 4  absent the stop mechanism. 
           [0017]      FIG. 6  is a sectional view taken through line  6 - 6  of  FIG. 5 . 
           [0018]      FIG. 7  is a sectional view taken through line  7 - 7  of  FIG. 5 . 
           [0019]      FIG. 8  is a sectional view taken through line  8 - 8  of  FIG. 5 . 
           [0020]      FIG. 9  is a perspective view similar to  FIG. 4  of another swivel base having two stop mechanisms. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0021]    A corner cabinet  10  is shown in  FIG. 1  to contain a shelf  12  that can be supported on a swivel base  14  to permit rotation of the shelf  12  within the cabinet  10 . The cabinet  10  can include sides  16  and  18  having edges  20  and  22  defining an opening  24  in the cabinet. The swivel base  14  can include features described below intended to insure that the shelf  12  can be reliably oriented with respect to the opening  24 . The swivel base  14  is situated between the shelf  12  and a cabinet base surface  26 . The cabinet  10  can include a kick plate  28  situated below the base surface  26 . A top  30  can join the sides  16  and  18  to each other. The top  30  typically includes a front edge  32 , which can assume shapes other than that shown, further defining the opening  24 . The cabinet  10  can also include back surfaces  34  and  36 . A door panel, not shown, can be secured to the cabinet  10  or to the shelf  12  to close the opening  24  when the shelf  12  is rotated to a “rest” position. 
         [0022]    The shelf  12  can have a top surface  38  as shown in  FIG. 2 . The shelf  12  can have a perimeter  40  defined by a rounded back portion  42  and a front edge  44 . The front edge  44  can be linear as shown in  FIG. 2  or can include a generally V-shaped indentation depicted by phantom line  46 , and can assume some other shapes, not shown. The shelf  12  can be rotated about a point  48  equal distant from all points on the rounded back portion  42 . The shelf  12  can include an aperture  50  that extends through the shelf  12  from the top surface  38  to the bottom surface  52 . A plug  54  can be provided to close the aperture  50  following installation of the shelf  12 . 
         [0023]    The bottom surface  52  of the shelf  12  is shown in  FIG. 3 . The swivel base  14  is shown attached to the bottom surface  52 . The swivel base  14  can include a smaller inner ring  56  and a larger outer ring  58 , which is larger than the smaller ring  56 . The larger ring  58  can be secured to the bottom surface  52  of the shelf  12  by a plurality of fasteners  60  so that the ring is centered around point  48 . A support plate  62  can be secured to the smaller ring  56 . 
         [0024]    An upper surface  64  of the larger outer ring  58  can be seen in  FIG. 4 . A plurality of openings  66  are seen in the upper surface  64  that can receive the fasteners  60  to secure the ring  58  to the bottom surface  52  of the shelf  12 . An outer surface  68  of the outer ring  58  can be seen to include a contoured surface portion  70  including a pair of radially outwardly projecting lobes  72  separated by an indentation  74  defining a detent  76 . The smaller ring  56  is seen to include an inwardly extending flange  78 . A plurality of openings  80  can be spaced around the flange  78  to receive fasteners, not shown, for securing the smaller ring  56  to the underlying surface  26 . A pair of projections  82  can be fixed to the flange  78  so as to straddle opening  84 , which is one of the openings  80 . An opening  85 , which is one of the openings  80 , is located adjacent to the indentation  74  defining the detent  76 . 
         [0025]    The support plate  62  can be seen to be secured to the smaller ring  56  by a plurality of fasteners  86 . The support plate  62  supports an arm  88  on a pivot mechanism  90 . The arm  88  can have a wedge surface  92  suitable for insertion into the indentation  74  between the pair of adjacent lobes  72  on the contoured surface  70  of the larger outer ring  58 . A spring  94  can be situated between an obverse surface  96  of the arm and an upstanding flange  98  of the support plate  62 . The spring  94  can bias the wedge surface  92  as a follower into contact with the surface  68  of the outer ring  58 . The rings  56  and  58  are shown in  FIG. 4  in a “rest” position with the wedge surface  92  received in the indentation  74 . 
         [0026]    A lower surface  100  of the larger outer ring  58  can be seen in  FIG. 5 . The lower surface  100  can include a plurality of arcuate channels  102  as shown in cross section in  FIG. 7 . The arcuate channels  102  can be separated by a plurality of partial height webs  104  as shown in cross section in  FIG. 6  and full height webs  106  as shown in cross section in  FIG. 8 .  FIG. 5  also shows the openings  80  spaced around the flange  78  of the inner ring  56 . Additional openings  108  are shown in the flange  78  intended to receive the fasteners  86  for securing the support plate  62  to the ring  56 . 
         [0027]      FIG. 6  shows a sectional view taken through line  6 - 6  of  FIG. 5  revealing an outwardly facing race surface  110  on the inner ring  56 . An inwardly facing race surface  112  can be seen on the outer ring  58  to confront the race surface  110 . The race surfaces  110  and  112  can extend completely around the inner ring  56  and outer ring  58 , respectively. A plurality of low friction members  114  can be positioned between the race surfaces  110  and  112  to facilitate the relative rotation of the swivel base members  56  and  58 . The low friction members  114  can take the form of balls, which can be made of metal such as steel. Other materials that can be used for the low friction members  114  include polymers such as nylon or polyoxymethylene (Delrin). 
         [0028]      FIG. 7  shows a sectional view taken through line  7 - 7  of  FIG. 5  again revealing the outwardly facing race surface  110  on the inner ring  56  confronting the inwardly facing race surface  112  on the outer ring  58 , the race surfaces  110  and  112  being separated by the low friction members  114 .  FIG. 7  also reveals the depth of the arcuate channels  102  and the projections  82  extending downward below the lower surface  116  of the flange  78  of the smaller inner ring  56 . The projections  82  can be seen to have a point  118  suitable for piercing the base surface  26 . The projections  82  can take the form of hardened steel points pressed or screwed into the flange  78  at the indicated locations so as to extend below the lower surface  116  by about 0.030 inches (0.76 mm). 
         [0029]      FIG. 8  shows a sectional view taken through line  8 - 8  of  FIG. 5  again revealing the outwardly facing race surface  110  on the inner ring  56  confronting the inwardly facing race surface  112  on the outer ring  58 , the race surfaces  110  and  112  being separated by the low friction members  114 .  FIG. 8  also reveals one of the fasteners  60  received in one of the openings  66  extending through the thickest portion  106  of the outer ring  58 . The fasteners  60  are used to secure the outer ring  58  to the bottom surface  52  of the shelf  12  as shown in  FIG. 3 .  FIG. 8  also reveals a fastener  118  extending through one of the openings  80  in flange  78  of the inner ring  56 . The fasteners  118  act to secure the inner ring  56  to the base surface  26  of the cabinet  10  or other similar structure. 
         [0030]    The shelf  12  can be installed into the base surface  26  of the cabinet  10 , or other similar structure, by first securing the outer ring  58  of the swivel base  14  to the lower surface  52  of the shelf  12  so that the aperture  50  through the shelf  12  can be aligned serially with the plurality of openings  80  in flange  78  of the inner ring  56 . Next, the shelf  12 , with the swivel base  14  attached, is positioned on the underlying base surface  26  at a desired location in relation to the cabinet opening  24  with the aperture  50  through the shelf  12  aligned with one of the openings  80  in flange  78 , preferably opening  85  situated adjacent to the indentation  74  defining the detent  76 . A first fastener  118  is inserted through the shelf aperture  50  into the aligned first swivel member opening  80  into engagement with the underlying base  26  with sufficient force to embed the projections  82  on the opposite side of the ring  56  in the underlying base surface  26 . The penetration of the single first fastener  118 , preferably into opening  85 , and the projections  82  sufficiently stabilizes the position of the swivel base  14  so that the shelf  12  can be rotated to reveal serially each of the other openings  80  through the aperture  50 . As each opening  80  is revealed, another fastener  118  can be installed to secure the position of the flange  78 , and swivel base  14 , on the underlying base  26  of the cabinet  10 . Following installation of fasteners  118  in all of the openings  80 , the plug  54  can be installed into the upper surface  38  of shelf  12  to hide any appearance of the aperture  50 . 
         [0031]    This same or similar installation method can be used to install swivel bases  14  not having a follower mechanism defining a “rest” position. The same or similar installation method can also be used to install swivel bases  14  having more than one follower mechanism as shown in  FIG. 9 .  FIG. 9  is a perspective view similar to  FIG. 4  of another swivel base  120  having two support plates  62  secured to the smaller ring  56  by a plurality of fasteners  86  on opposite sides of the axis of rotation Y of the swivel base  120 . Each of the support plates  62  supports an arm  88  on a pivot mechanism  90 . Each arm  88  can have a wedge surface  92  suitable for insertion into the indentation  74  between the pair of adjacent lobes  72  on the contoured surface  70  of the larger outer ring  58 . Each spring  94  can be situated between an obverse surface  96  of the arm and an upstanding flange  98  of the respective support plate  62 . Each spring  94  can bias the adjoining wedge surface  92  as a follower into contact with the surface  68  of the outer ring  58 . The rings  56  and  58  are shown in  FIG. 9  mid-way between two “rest” positions defined by one of the wedge surfaces  92  being received in the indentation  74 . 
         [0032]    From the forgoing description of the structure and operation of a preferred embodiment of the present invention, it will be apparent to those skilled in the art that the present invention is susceptible to numerous modifications and embodiments within the ability of those skilled in the art and without exercise of the inventive facility. Accordingly, the scope of the present invention is defined as set forth of the following claims.