Abstract:
Apparatus and system for leveling a playing surface on a table, such as a billiards or pool table, which utilizes a plate which supports the playing surface and which is tiltable about an x and y-axis for maintaining contact with the playing surface regardless the angle of the surface relative to the frame. Further, the apparatus is height adjustable to assist with leveling the playing surface in engagement with the plate of the leveling apparatus. Leveling apparatus are also provided between the legs of the table and the frame and which can be pre-leveled before positioning the playing surface to minimize the amount of leveling required to level the playing surface relative to the frame.

Description:
FIELD OF THE INVENTION 
       [0001]    Embodiments of the invention relate to systems for leveling a playing surface of a table and more particularly to apparatus for leveling a playing surface, such as a billiards table. 
       BACKGROUND OF THE INVENTION 
       [0002]    A variety of playing surfaces require leveling in order to permit proper movement of playing pieces thereon. Certain games, such as billiards and pool and the like, are very sensitive to proper leveling in order to fairly allow the balls to travel on the surface. 
         [0003]    In most tables used for billiards, a wooden frame is supported on a plurality of legs and a playing surface, such as slate, is supported on the wooden frame. The slate surface may be provided in a single piece or in a plurality of pieces which are positioned side by side on top of the frame. Thus, both the leg and frame assembly may be off-level as can be the slate or portions of the slate. Leveling therefore becomes complex. 
         [0004]    Conventionally, leveling may be performed using shims which are placed below the table legs and/or between the slate and the frame. Due to the weight of the entire assembly, lifting the entire table or even portions of the slate is difficult and may be very time consuming. Positioning of the shims requires much trial and error. 
         [0005]    Alternately, Applicant is aware of externally threaded leveling feet which are attached to a lower surface of each of the table legs for leveling the table. Typically, the area of contact between the leveling foot and the floor is reduced and there is difficulty in handling the weight of the table while adjusting the height of the leveling feet. 
         [0006]    Many have attempted to provide solutions to the problem of leveling. 
         [0007]    U.S. Pat. No. 1,860,215 to Young teaches screws having swivel plates attached to one end and flattened wings attached to the other for raising and lowering support bars which extend lengthwise under the bed within the outer frame of the table for raising and lower the bed during leveling. 
         [0008]    U.S. Pat. No. 3,658,328 to Kooker teaches vertically extending leveling screws which extend between a cast concrete pedestal and a cast concrete top of the table for adjusting the level thereof. 
         [0009]    U.S. Pat. No. 4,027,878 to Dadbeh teaches support bars mounted transversely within the frame for supporting the bed and bed-level slide brackets slidably mounted on the support bars for movement therealong to a plurality of positions beneath the bed. An adjusting mechanism, which incorporates a threaded screw and a flat head attached thereto, is connected to the bracket for adjusting the level of the bed. 
         [0010]    U.S. Pat. No. 5,161,797 to Frasca teaches leveling means used between the table legs and the table frame and leveling means between the table frame and the slate. A head of the adjustable rod used between the slate and the table is embedded in the slate top and is supported to extend vertically upward from the frame by an angle bracket affixed thereto. 
         [0011]    U.S. Pat. No. 5,839,966 to Eisenhauer et al teaches slate levelers having a threaded shank received in an associated nut in a radially outwardly directed flange at one end of the shank at an interface between the top plate of the table and the slate sheets and engages the slate sheets for adjustable leveling. The flange is rigidly connected to the shank. The levelers are positioned about a periphery of each sheet of slate. 
         [0012]    U.S. Pat. No. 6,132,320 to Spoerl et al teaches externally threaded support rods having a collar threaded thereon a support member upon which the playing surface rests and a fastener for securing the apparatus to an underlying surface. 
         [0013]    In all cases where leveling occurs between the table and the slate, the prior art apparatus provide a rigid contact surface for engaging the slate, thus the apparatus may not remain fully in contact with the slate. 
         [0014]    Clearly there is interest in apparatus for reliably and securely leveling playing surfaces to ensure proper movement of playing pieces, such as balls, thereon. 
       SUMMARY OF THE INVENTION 
       [0015]    Apparatus and a system for leveling a playing surface using at least said apparatus enable leveling of the playing surface with reduced point loading on the playing surface to prevent damage thereto. 
         [0016]    In a broad aspect of the invention, apparatus for leveling a playing surface supported in a frame comprises: a bracket for connection to the frame; a threaded member supported in the bracket and extending axially upwardly therethrough, an effective height of the member being adjustable axially along a z-axis within the bracket; and a contact plate for supporting the playing surface thereon in a substantially level orientation, the contact plate supported at a top end of the threaded member for tilting about an x-axis and a y-axis, the plate being moveable thereabout for freely orienting the contact plate relative to an underside of the playing surface so as to substantially maintain distributed contact with the playing surface when the effective height of the threaded member is adjusted to position the plate at the underside of the playing surface. 
         [0017]    Preferably, the contact plate is connected to the threaded member through a ball and socket type connection. The apparatus are connected to the frame supporting the playing surface about the periphery of the playing surface avoiding supporting the playing surface from cross-members which may be susceptible to warping and the like. 
         [0018]    In a further broad aspect of the invention, a system for leveling a playing surface supported in a frame having a plurality of legs for supporting the frame, the system comprises: apparatus for leveling the frame on the plurality of legs, each leg leveling apparatus comprising: one or more externally threaded rods connected between the leg and the frame for supporting the frame thereon, each of the one or more rods being axially moveable therebetween for adjustment to an effective height for leveling the frame relative to the leg; and apparatus for leveling the slate relative to the frame, each slate leveling apparatus comprising: a bracket for connection to the frame; a threaded member supported in the bracket and extending axially upwardly therethrough, an effective height of the member being adjustable axially along a z-axis within the bracket; and a contact plate for supporting the playing surface thereon in a substantially level orientation, the contact plate supported at a top end of the threaded member for tilting about an x-axis and a y-axis, the plate being moveable thereabout for freely orienting the contact plate relative to an underside of the playing surface so as to substantially maintain full contact with the playing surface when the effective height of the threaded member is adjusted to position the plate at the underside of the playing surface, wherein the effective height of each of the one or more rods of each leg leveling apparatus are adjusted so as to level the frame supported on the legs; and thereafter, the effective height of the threaded member of each of the slate leveling apparatus is adjusted for leveling the slate relative to the frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1   a  is a partial top perspective view of a table illustrating a system according to an embodiment of the invention for leveling a playing surface, the playing surface having been removed for clarity, the system comprising slate leveling apparatus and leg leveling apparatus; 
           [0020]      FIG. 1   b  is a detailed perspective view of a leg of the table according to  FIG. 1   a  illustrating a portion of the leg leveling apparatus; 
           [0021]      FIG. 2  is a an exploded top perspective view illustrating an embodiment of the slate leveling apparatus positioned about the frame for supporting a plurality of pieces of the playing surface which are removed and shown ready for installation thereon; 
           [0022]      FIG. 3  is a partially exploded view according to  FIG. 2 , one of the plurality of pieces of playing surface having being installed and supported about a periphery by the slate leveling apparatus; 
           [0023]      FIGS. 4   a - 4   d  are perspective views of an embodiment of the leg leveling apparatus according to  FIGS. 1   a  and  1   b , more particularly, 
           [0024]      FIG. 4   a  is a sectional view of a top of a leg illustrating a socket installed therein and supporting a threaded rod through a base plate of a mounting bracket, upstanding portions of a frame mounting bracket having been removed for clarity; 
           [0025]      FIG. 4   b  is a top perspective view of the leg according to  FIG. 4   a , illustrating countersinking of the sockets therein; 
           [0026]      FIG. 4   c  is a top perspective view of the leg according to  FIG. 4   a , threaded rods being installed in the sockets; and 
           [0027]      FIG. 4   c  is a top perspective view according to  FIG. 4   a , the mounting bracket having been installed thereon; 
           [0028]      FIG. 5  is a perspective view of the slate leveling apparatus according to an embodiment of the invention; 
           [0029]      FIG. 6  is a perspective view of the slate leveling apparatus according to an embodiment of the invention; and 
           [0030]      FIG. 7  is a perspective view of the slate leveling apparatus according to  FIG. 6  installed on the frame of a table. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0031]    Embodiments of the invention are described herein in the context of a billiards or pool table. As one of skill in the art would appreciate, leveling apparatus, according to embodiments of the invention, may be applied to other types of playing surfaces which require leveling to ensure proper play. 
         [0032]    Well known in the prior art, as shown in  FIGS. 1-3 , a billiards table  1  typically comprises a frame  2  supported on legs  3  which are positioned at least at corners  4  of the frame  2 . Longitudinal and transverse support members  5  typically extend within the frame  2  to provide structural rigidity thereto and to support the weight of a playing surface  6 . In the case of a billiards or pool table  1 , the playing surface  6  is typically made of slate or other suitable composite material. 
         [0033]    Having reference to  FIGS. 2 and 3 , the slate playing surface  6  may be installed as a single piece, but is more likely to be installed in a plurality of pieces as shown. A typical eight foot table  1  may have three separate pieces of slate for forming the playing surface  6 , the pieces being laid side by side for forming a contiguous surface upon which a fabric, such as felt, is applied. The weight of the slate playing surface  6  for an eight foot table averages from about 250 kg to about 290 kg. 
         [0034]    With reference to  FIGS. 1-6 , and in embodiments of the invention, a leveling system comprises a plurality of slate leveling apparatus  10  positioned between the frame  2  and the slate playing surface  6  and one or more leg leveling apparatus  11 , which are positioned between the legs  3  and the frame  2 . Thus, the frame  2  can be leveled relative to a surface upon which it is supported and further, the slate playing surface  6  can be leveled to overcome imperfections and the like in the frame  2 . In embodiments of the invention, the table frame  2  is leveled first, after which the slate playing surface  6  can be leveled when attached to the pre-leveled frame  2 . 
         [0035]    In one embodiment, as shown in  FIGS. 1-4D , the one or more leg leveling apparatus  11  are used between each leg  3  and the frame  2  to level the frame  2  of the table  1  on the legs  3 . Each leg leveling apparatus  11  comprises an externally threaded rod  12  which is extends into a bore  13  formed in a top  14  of each table leg  3 . The rod  12  extends axially upwards therefrom for supporting the frame  2 . In one embodiment of the invention, best seen in  FIG. 4A , at least an internally threaded socket  15  is fit within the bore  13  in the top  14  of the leg  3  for retaining the rod  12  to the leg  3 , the rod  12  being axially moveable by rotation therein. A washer  16  is secured to the rod  12  and is countersunk into the top  14  of the leg  3  when the rod  12  is fully engaged in the socket  15 . As shown, in one embodiment, a top end  17  of the rod  12  is profiled to permit drivable rotation of the rod  12 , using means such as an Allen wrench  18  for engaging the profiled top  17 , within the socket  15  for adjusting an effective height of the rod  12  so as to level the frame  2  which is connected thereto. As the rod  12  is rotated, the washer  16  is elevated above the top  14  of the leg  3  for supporting a frame mounting bracket  20  thereon. In one embodiment a lock nut  19  is used to secure the position of the rod  12  once adjusted. 
         [0036]    In one embodiment, best seen in  FIG. 4D , three leg leveling apparatus  11  are fit in the top  14  of each leg  3 , typically in a triangular pattern. The frame mounting bracket  20  is positioned over the rods  12  extending therefrom. Adjustment of the effective height of each of the threaded rods  12  permits the frame  2  of the table  1  supported in the frame mounting bracket  20  which are further supported by the washers  16  of the rods  12  to be pre-leveled on the legs  3  relative to the support surface, typically a floor, before installation of the slate playing surface  6 . 
         [0037]    The frame mounting bracket  20  further comprises one or more upstanding members  21  to which the frame  2  is secured. In one embodiment, the one or more upstanding members  21  form a corner  22  which complies to the corner  4  of the frame  2 , the frame  2  being secured to an outside thereof. The one or more upstanding members  21  of the frame mounting bracket  20  may be formed of a single piece of material, such as metal, which is bent to form the corner  22 . The upstanding corner member  21  is then secured, such as by welding, to a lower horizontal plate  23  through which the threaded rods  12  extend and which sits atop the leg  3 . 
         [0038]    Having reference to  FIGS. 1A ,  2 , and  3 , a plurality of the slate leveling apparatus  10  are attached about the frame  2  of the table  1  for supporting the slate playing surface  6 . In one embodiment, the slate leveling apparatus  10  are only attached to the frame  2  and not to the longitudinal and transverse members  5  for ease of leveling and to prevent changes in level which may occur as a result of warping of the transverse and longitudinal supports  5 . In one embodiment, the plurality of slate leveling apparatus  10  engage the slate playing surface  6  at a portion of a periphery  30  of the slate playing surface  6 . 
         [0039]    Best seen in  FIGS. 5 and 6 , each of the slate leveling apparatus  10  comprises a bracket  31  for connection to the table frame  2 , the bracket  31  having a flange  32  extending inwardly therefrom and inwardly from the frame  2 . The flange  32  supports a threaded member  33  extending upwardly therein for axial movement along a z-axis for adjusting an effective height of the threaded member  33  of the slate leveling apparatus  10 . The threaded member  33 , typically a bolt, further comprises a contact plate  34  secured at a top end  35  for tilting about an x-axis and a y-axis. In one embodiment, the contact plate  34  is connected to the bolt through a ball and socket connection  36 . The contact plate  34  is thus permitted to freely rotate to orient about two degrees of freedom to conform to an underside of the slate when the bolt is threaded to the effective height to engage the plate with the underside  37  of the playing surface  6 . Thus, the plate  34  is permitted to remain substantially in distributed contact with the underside  37  of the slate playing surface  6  regardless the angle of the slate playing surface  6  relative to the frame  2 . Distributed contact of the plate  34  with the slate playing surface  6  is beneficial as any point loading which may otherwise result in damage to the slate playing surface  6  is thereby reduced. 
         [0040]    In one embodiment, shown in  FIGS. 5-7 , the bracket  31  further comprises a planar attachment plate  38  which conforms to the angle of the frame  2  for connection to an inner side  39  of the frame  2 . An upper tab  40  extends outwardly from a top  41  of the attachment plate  38 , for fitting substantially parallel to a top edge  42  of the frame  2  for attachment thereto. In one embodiment, the top edge  42  of the frame  2  may be notched to countersink the tab  40  even with the top  42  of the table  1 . The bolt-supporting flange  32  extends horizontally outwardly from a face  43  of the attachment plate  38  for positioning the contact plate  34  and threaded member  33 , substantially parallel to the top  42  of the frame  2 . A support member  44  extends from an edge  45  of the attachment plate  38  for supporting the bolt-supporting flange  32  along an edge  46 . In one embodiment, the bolt-supporting flange  32  and support member  44  are formed as a unitary angled member. Further, the tab  40  is unitary to the attachment plate  38 . 
         [0041]    One or more nuts  50  are threaded onto the threaded member  33 , to fix the effective height of the threaded member  33  in the flange  32  and thereby adjust the height of the contact plate  34  relative to the top  42  of the frame  2 . A single nut  50  can be welded to the flange  32  or nuts  50 , 50  can be used above and below the flange  32  for securing the height of the bolt  33  relative thereto. 
         [0042]    In one embodiment, wherein the frame  2  of the table  1  is angled inwardly at a bottom  51  of the frame  2 , the attachment plate  38  is suitably angled relative to the upper tab  40  to permit mounting the attachment plate  38  flush with the inner surface  39  of the frame  2 . 
         [0043]    In one embodiment, as shown, slate leveling apparatus  10  are positioned to support each piece of slate  6  at each corner thereof. As the frame  2  of the table  1  has typically been pre-leveled using the leg leveling apparatus  11 , little adjustment has to be made to the slate leveling apparatus  10  in order to level the slate playing surface  6  relative to the frame  2 . 
         [0044]    In one embodiment, an upper surface  52  of the contact plate  34  is concave so as to provide at least two points of contact for the slate playing surface  6  to accommodate imperfections in the slate playing surface  6 , thus assisting in providing more even distribution of the load across the entirety of the contact plate  34 .