Abstract:
The sliding table has a stationary bed and a carriage which is movable relative to the bed. The carriage has an upper surface on which a work piece is seated. The bed has rollers and the bed has a track. Alternatively, the bed has a track and the carriage has rollers. In either case, the rollers roll back and forth in the track. Either the rollers are biased into contact with the track or the track is biased into contact with the rollers. In the former case, an eccentric and a coil spring are used to bias the rollers. In the latter case, the track has a bearing plate which is biased by a rubber strip or O-ring cord stock into contact with the rollers.

Description:
FIELD OF THE INVENTION 
   This invention relates to sliding tables for use in conjunction with any machine or workbench that is used for doing mechanical or practical work. More particularly the invention relates to a sliding table for use in conjunction with a workbench or a machine such as a table saw, router table, shaper, drill press, band saw or workbench. The sliding table has means for accurately guiding the movement of the table and minimizing rocking of the table on its longitudinal and transverse axes. 
   BACKGROUND OF THE INVENTION 
   Sliding tables for workbenches are known for providing lateral support to a piece of work or stock in front of or behind the workbench. Such tables usually travel on a path which is perpendicular to the longitudinal axis of the workbench. The path extends from in front of the workbench to behind it and, in general, the longer the path, the more useful and versatile the table is. However the table become increasing unstable as the path lengthens. That is because the longer the path, the larger the portion of the table that is cantilevered when the table is at the ends of its travel. The cantilevered portion is not supported and for that reason is relatively unstable. Any weight on the table may cause the machine or workbench to tip over or may cause the table to bend or fracture. 
   I have found a way of significantly extending the length of travel of a sliding table while at the same time providing improved control and guidance of a piece of work on the sliding table. The way in which I do so involves the use of, among other things, a movable carriage on which the piece of work is located. I also use spring-loaded rotating means such as rollers. Alternatively, bearing plates apply pressure to rollers for accurately guiding the table while it is sliding so that precise work can be carried out on the table. 
   SUMMARY OF THE INVENTION 
   Briefly, the sliding table of my invention is used for guiding a work piece including: a bed adapted to be immobilized and a carriage movable relative to the bed and having a surface upon which the work piece is adapted to be located. Either the bed or the carriage has rotating means and the other has a track in which the rotating means revolves. Resilient means is provided for causing the rotating means and the track to be biased toward each other. 

   
     DESCRIPTION OF THE DRAWINGS 
     The sliding table of the invention is described with reference to the accompanying drawings in which: 
       FIG. 1  is a perspective view of the sliding table in conjunction with a table saw; 
       FIG. 2  is a plan view of the sliding table and table saw; 
       FIG. 3  is a perspective view of a bed of the sliding table; 
       FIG. 4  is an enlarged fragmentary perspective view of the bed; 
       FIG. 5  is a fragmentary perspective view of the carriage which slides on the bed; 
       FIG. 6  is a section of a portion of the carriage; 
       FIG. 7  is a enlarged fragmentary perspective view of the carriage and bed; 
       FIG. 8  is an elevation of the components illustrated in  FIG. 7  from the front; 
       FIG. 8   a  is an elevation of the bed and carriage in which the carriage is provided with rollers and the bed is provided with a track. 
       FIG. 9  is an elevation a portion of the bed from the side showing two rollers on which the carriage slides; 
       FIG. 10  is an exploded perspective view of the components of one of the rollers of a second embodiment of the sliding table; 
       FIG. 11  is a sectional view of the roller illustrated in  FIG. 10  in conjunction with a sectional view of a portion of the carriage adjacent to the roller. 
   

   Like reference characters refer to like parts throughout the description of the drawings. 
   DESCRIPTION OF PREFERRED EMBODIMENTS 
   With reference to  FIGS. 1 and 2 , the sliding table of the invention, generally  10 , is shown in conjunction with a table saw, generally  12 . The table saw is conventional and consists of a housing  14  and an upper panel  16  having a working surface  18  through which a circular saw blade  20  projects. An electrical box  22  having on-off switches control the operation of the saw. 
   The sliding table includes a bed, generally  30  and an upper carriage, generally  32  which is mounted for sliding on the bed. 
   With reference to  FIGS. 1 and 3 , the bed is provided with a bracket  34  having a vertical leg  34   a  which is bolted to the side edge  36  of the table saw and a lower horizontal leg  34   b  on which a roller assembly, generally  38 , is mounted. 
   With reference to  FIGS. 3 and 4 , the roller assembly includes a framework  40  to which a number of rollers  42  are mounted for rotation. The rollers are arranged in groups of six spaced along the length of the framework. A pair of rollers  42   a  in each group is disposed centrally between the other rollers in the group and rotates about a vertical axis  44 - 44 . The remaining rollers  42   b  in the group are arranged outwardly of the central rollers. The outer rollers are arranged in pairs on opposite sides of the central rollers and rotate about a horizontal axis  46 - 46 . 
   The framework has a central longitudinally extending I-shaped segment  50 . The central rollers  42   a  are mounted for rotation on lower horizontal wall  50   a  of the I-segment and extend through openings in its upper horizontal wall  50   b . On opposite sides of the central I-segment and spaced apart therefrom are distal I-shaped segments  52 . The outer rollers  42   b  are mounted for rotation to the inner vertical walls  52   a  of the distal segments and extend through openings in its outer vertical wall  52   b.    
   The spaces between the central and distal I-segments, marked by arrows  54 , constitute two parallel longitudinally extending slots or tracks for receipt of downwardly extending flanges  56   a,b  formed on the carriage. The flanges are shown in  FIG. 5  and are described in detail below. 
   With reference to  FIGS. 5 and 6 , the carriage is provided with an upper wall  60  with an upper surface  62  which is flush with the working surface  18  of the table saw. Grooves, generally  64 ,  66 , are formed in the upper wall. The grooves which are horizontally spaced and longitudinally extending are provided to accommodate a fence. An example of such a fence is described in my co-pending applications for patents filed in the United States Patent &amp; Trademark Office under Ser. No. 10/678,228 and in the Canadian Intellectual Property Office under serial no. 2,444,371. Both applications were filed on Oct. 6, 2003. 
   The flanges  56   a,b  are spaced apart from one another and each is made up of a downwardly extending vertical limb  70  and a short horizontal limb  72  at the lower end of the vertical limb. The side walls of vertical limbs which face one another define opposite sides of a track, generally  74 . On the inside wall of flange  56   a  is a pair of vertically spaced longitudinally extending grooves  76 . Each groove receives an elongated strip  78  of rubber, O-ring cord stock or like deformable flexible material. 
   A longitudinally extending groove  80  is also formed in the horizontal limb  72  of flange  56   a  and a second longitudinally extending groove  82  is formed in the lower surface of wall  60 . Groove  82  is vertically above groove  80  and both grooves receive a vertically extending bearing plate  84 . The bearing plate extends the length of the carriage and is biased outward by the resiliently deformable strips  78 . 
   Flange  56   b  also has a bearing plate  84  mounted in grooves in the flange. The two bearing plates in flanges  56   a,b  face one another and the space between them defines the side wall boundaries of track  74  in the carriage. 
   Flanges  56   a,b  are arranged centrally of the carriage. Disposed outwardly of the central flanges are distal flanges  90   a,b . With reference to  FIGS. 5 and 6 , the distal flanges are also L-shaped but their lower horizontal limbs  94  are longer than those of flanges  56  for accommodation of a pair of parallel grooves  96 . The latter grooves receive elongated strips  98  of resiliently deformable material. 
   Horizontally opening grooves  100  in each distal flange receive a bearing plate  102  which is biased outwardly by resiliently deformable strips  98 . Vertically above the bearing plate  102  is another bearing plate  104  mounted in a groove in a short flange  106  and in the vertical limb  108  of the distal flange. The two bearing plates  102 ,  104  face one another and the space between them forms a outer track  110  in the carriage. The upper side face  102   a  of the bearing plate is in contact with the roller within track  110 . The oppositely facing lower side face  102   b  of the bearing plate faces grooves  96  in which the strips of resiliently deformable are located. 
   With reference to  FIG. 8 , the central rollers  42   a  are received in central track  74  in the carriage such that the outer walls of the rollers contact the bearing plates  84  on opposite sides of the rollers. Similarly outer rollers  42   b  are received in tracks  110  such that their outer walls contact bearing plates  102 ,  104 . 
     FIG. 8   a  is the same as  FIG. 8  except that rollers  42   a,b  are provided on the carriage while the track  74  is provided in the bed. The bed is attached to the side edge  36  of the workbench while the carriage is floating. 
   In operation and with reference to  FIG. 9 , the bearing plates, biased by the strips of resiliently deformable material, minimize rocking of the carriage on its longitudinal axis  142 . In that Figure the carriage has rocked clockwise and the upper wall of roller  42   d  bears against the upper bearing plate  142  while the lower wall of roller  42   e  bears against the lower bearing plate  146  and causes it to deform slightly. The resiliently deformable strips behind the two bearing plates will resist such deformation and will urge the plates to return to their undeformed state. As the plates return. they will dampen the rocking movement of the carriage. 
   In like manner and with reference to  FIG. 7 , central rollers  42   a  minimize rocking of the carriage on its transverse axis  148 - 148  since such rocking will force some of the central rollers into contact with the bearing plate behind which the resiliently deformable strips are located. The strips will resist deformation of the bearing plates and will urge the plates to return to their undeformed state. Lateral movement will be dampened by such movement. 
   In the embodiment of the sliding table just described, bearing plates biased by the strips of resiliently deformable material dampen the rocking of the carriage. In the second embodiment of the invention described below, the rollers are spring loaded and it is they that dampen the rocking of the carriage. 
   With reference to  FIGS. 10 and 11 , roller  42   c  is connected to eccentric  120  and the eccentric in turn is connected to a threaded shank  124 . The shank passes through an opening  126  in wall  128  of the framework and is held to the plate by means of nut  130 . The nut prevents the shank from withdrawing from wall  128  but does not prevent the shank from pivoting relative to the wall. A coil spring  132  encircles the shank and one of its ends is received in an opening  134  in the wall while the other end engages the outer wall of the shank. The spring urges the shank to pivot clockwise and as the shank pivots, the roller is urged in the direction of the arrow in  FIG. 11  into contact with bearing plate  140 . 
   It will be understood that the rollers of  FIGS. 10 and 11  may be substituted for the rollers of the preceding  FIGS. 1 to 9  in which case pressure plates and rubber strips may be dispensed with. The carriage will resist rocking in both the longitudinal and lateral directions. 
   The rollers are biased into pressure plate  140  of the track  142 . Alternatively, the pressure plate may be provided on the carriage in which case the rollers are provided on the track. 
   It will be understood, of course, that modifications can be made in the embodiments of the invention illustrated and described without departing from the scope and purview of the invention as set in the appended claims.