Patent Abstract:
A fence for guiding a work surface past a saw blade supported by a table having a support tube running substantially perpendicular to the saw blade. The fence includes a rip fence having a plurality of studs disposed on opposing sides thereof. A pair of fence faces are positioned on opposing sides of the rip fence and have a plurality of slots for removably engaging the studs thereby securing the face fences to the rip fence. A rip fence head is affixed beneath the rip fence. A lockdown clasps the support tube with the rip fence head for securing the fence to the tablesaw. The lockdown includes an adjustment mechanism for stabilizing the fence to the support tube independently of the lockdown. The adjustment mechanism is adjustable relative to the lockdown so that the position of the fence on the support tube can be accurately adjusted by moving the fence relative to the lockdown mechanism.

Full Description:
This application is a divisional application of application Ser. No. 10/657,289, filed Sep. 8, 2003, which is a divisional application of U.S. patent application, Ser. No. 10/076,173, filed Feb. 14, 2002 now U.S. Pat. No. 6,647,847, which claims the benefit of Provisional Application No. 60/269,115, filed Feb. 15, 2001. 

   BACKGROUND OF THE INVENTION 
   This invention relates to an improved fence for a table mounted tool, such as for example a tablesaw, shaper, oscillating spindle sander, band saw, router table, etc. More specifically, the subject invention relates to an improved attachment for securing the fence to a table mounted tool and an improved way of replacing the fence faces or attaching accessory tools. For simplicity and clarity, the present invention will be described with respect to a tablesaw, but it should be understood that it will work well with any table mounted tool. 
   Fences have become standard equipment for use with most tablesaws to accurately guide a workpiece past a saw blade. Fence faces disposed on the fence must remain oriented parallel to the saw blade even after repeated uses to ensure accuracy and repeatability in the workpiece being cut. Presently available fences include widely varying types of lockdowns to secure the fence to the tablesaw. None of these lockdowns provide the ability to accurately tune the position of the fence relative to the saw blade. 
   Further, presently available fences do not provide the ability to quickly and easily remove the fence faces without the use of tools. These fence faces also include attachment access points that are exposed to the work area. 
   Therefore, it would be desirable to provide a fence having a lockdown that is convenient to use and yet provides the ability to obtain an accurate placement of the fence relative to the saw blade. It would be further desirable to provide a fence face that can be easily and quickly removed from the fence. 
   SUMMARY OF THE INVENTION AND ADVANTAGES 
   The present invention is a fence assembly for use with a table mounted tool such as a tablesaw. The fence includes a fence beam having opposed fence faces removably attached on opposite sides of the fence beam. A fence head forms an L-shaped section and is mounted to the end of the fence beam. An adjustment mechanism is attached to the fence head and receives the fence support, such as a support tube of the tablesaw. 
   The fence beam includes a plurality of fasteners mounted along each side. Each fence face includes a plurality of mating fasteners for securing the fence faces to the fence beam. In the preferred embodiment, studs are mounted along each side of the fence beam and a plurality of keyhole shaped slots are mounted on each fence face. The studs and the keyhole shaped slots provide the means to quickly remove and re-attach the fence faces to the fence beam. It should be appreciated that other fasteners could be used, such as for example magnets. 
   The adjustment mechanism of the present invention allows for both quick general mounting of the fence to the tablesaw and precise adjustment of the fence with respect to the saw blade. The adjustment mechanism includes a quick lockdown device for locking the fence in a generally desired location. To fine tune the adjustment of the fence with respect to the saw blade, an adjustment knob is provided. The adjustment knob can be rotated to move the fence a precise distance for each rotation of the knob. Once the fence is at the desired location, a main fence lockdown lever is depressed to lock the fence in its final position. The main fence lockdown lever includes a cam which engages a locking finger which when engaged by the cam engages the support tube of the tablesaw. 
   In the disclosed embodiment, the adjustment mechanism has a first mounting assembly which mounts the adjustment knob and a fine threaded shaft to the fence beam. The main fence lockdown device is mounted for movement with respect to the fine tuning mechanism. In this way, the main fence lockdown can be fixed to the support beam and the fence can be adjusted with respect to the support beam. 
   The fence faces can quickly and easily be replaced by way of the studs and the keyhole shaped slots. The adjustment mechanism and the cam provide the inventive fence with a lockdown that is mechanically simple and yet allows for accurate adjustments to the position of the fence relative to the tablesaw. The simple design of the lockdown enables the fence to provide an accurate and repeatable alignment surface relative to the saw blade that is not presently available. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
       FIG. 1  is a plan view of a tablesaw with the inventive fence; 
       FIG. 2  is a perspective exploded view of the fence of the present invention; 
       FIG. 3  is a partial top view of the fence with cut away views; 
       FIG. 4  is a side view of the quick lock lever and the main fence lock; 
       FIG. 5  is a partial cut away view of the fine adjustment mechanism; 
       FIG. 6  is a partial top view of the fence with cut away views; 
       FIG. 7  is a partial view of the main fence lock in the locked position; 
       FIG. 8  is an end view of the anti rotation tab and nut; 
       FIG. 9  is an end view of the beam and removable fence faces of the present invention; and 
       FIG. 10  is a partial end view of the beam with the fence face installed. 
       FIG. 11  is a top view of an example of a jig or accessory tool, a split type fence, mounted on a combination tablesaw and router table. 
       FIG. 12  is a partial exploded view of the jig of  FIG. 11 . 
       FIG. 13  is a partial perspective view of a further jig or accessory tool, a fixture base. 
       FIG. 14  is an end view of a still further jig or accessory tool, an extended fence. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , a fence assembly is generally shown at  10 . The fence  10  is used for guiding wood against a table mounted tool such as a saw blade  12  of a tablesaw  14 . The fence  10  sits upon a work surface  16  of the tablesaw  14  and is aligned parallel to the saw blade  12 . The tablesaw  14  includes a support tube  18  that runs perpendicular to the saw blade  14  as known in the art of tablesaws. Fence  10  is removably mounted to support tube  18 . The fence  10  includes opposing fence faces  20  that extend upwardly and are removably attached to opposite sides of fence beam  22 . 
   Referring to  FIGS. 9 and 10 , the preferred embodiment of the fence face  20  is illustrated. The fence faces  20  are removably affixed to opposing sides of the fence beam  22  by a plurality of studs  28  which project outwardly from each beam side  30  of the fence beam  22 . Each stud includes a head  32  and a shaft  34 . The radius of the head  32  is larger than that of the shaft  34 . The shaft  34  extends outwardly from beam side  30  so that the head  32  is distanced from the beam side  30 . In the disclosed embodiment, the studs  28  have a threaded portion  35  which threads into an internally threaded hole  37  in beam side  30 . Each of the fence faces  20  includes an inner face  36  and an outer face  38 . Each inner face  36  includes a plurality of plates  40  which is the preferred embodiment match in number the studs  28  on the fence beam  22 . With reference to  FIG. 2 , each of the plates  40  includes a keyhole shaped aperture  42 . The aperture  42  forms a slot having an enlarged end  44  for receiving the stud head  32  and a narrow end  45  for retaining the stud head  32 . In the disclosed embodiment, the fence faces have recesses  43  to receive the plates  40  and screws  47  retain the plates  40  in the recesses  43 . The fence faces  20  are each affixed to the fence beam  22  by inserting the stud head  32  into the enlarged end  44  of the keyhole shaped aperture  42  and sliding the stud head  32  into the narrow end  45 . 
   The stud  28  and the keyhole shaped aperture  42  enable the quick replacement of the fence faces  20  when worn without having to rotate the fasteners, i.e. without tools. Further, other useful fixtures can be affixed to the fence  10 . A sacrificial fence face designed to be sawed through while cutting can be quickly attached. Further, a fence face having a jig attached for providing additional support to a workpiece can be quickly attached. These will be described later. In the preferred embodiments, the fence faces  20  can be constructed of wood, plastic, metal, etc. Additionally, instead of the fasteners described, other non-rotating fasteners could be used such as magnets. 
   With reference to  FIG. 1 , it can be seen that fence beam  22  protrudes past the work surface  16 . This is an important advantage of the present fence  10  because it allows a work piece to engage more of the fence beam  22  before engaging the saw blade  12 . Due to the location of the fence head  26 , the advantageous extension can be obtained. 
   The fence head  26  is best shown in  FIG. 2  having a mounting member  48  affixed beneath the fence beam  22 . In the disclosed embodiment, a block  51  is welded between the member  48  and beam  22 . The mounting member  48  includes a side wall  49  that forms an L-shaped section with the top wall  46 . The top wall  46  includes pads  50  for resting against the support tube  18 . In the preferred embodiment, the pads are preferably plastic to allow the mounting member  48  to easily slide along tube  18 . The side wall  48  also includes at least two resilient panels  52  for squaring the fence head  26  to the tablesaw  14 . See  FIG. 3 . Each resilient panel  52  is adjustably spaced from the side wall  48  by a threaded spacer  53 . The spacer  53  can be turned to force the panel  52  against the support tube  18  to square the fence  10  with respect to the saw blade and to adjust the clamping force of the main fence lock  24 . Additionally, the panel  52  is offset to provide space between tube  18  and mounting member  48  to provide room for the saddle  86  which will be discussed in greater detail below. 
   As best shown in  FIGS. 1 ,  2 ,  4 , and  7 , the main fence lockdown assembly  24  includes a handle  54  with a shaft  56  having a grip  58  affixed at a distal end thereof. The shaft  56  extends opposite the grip  58  to a generally circular cam  60  that includes a cam surface  62 . The cam  60  is pivotally attached between opposing walls  64  and  84  of the bracket  63  with a threaded shaft  66  and a nut  68  that define the axis on which the cam  60  pivots. A tab  65  is provided to prevent the threaded shaft  66  from rotating. The cam  60  has an aperture  61  which receives the shaft  66 . The orientation of the cam surface  62  is changed by moving the handle  54  up or down. The cam  60  contacts a locking arm or finger  70  that includes a cam appendage  72  and a spring appendage  74 . 
   The cam appendage  72  and the spring appendage  74  form an L-shaped section. A locking arm bolt  66  and nut  68  affix the locking arm  70  to the bracket  63  by extending through an aperture  81  in arm  70  and aperture  69  in opposing walls  64  and  84  of bracket  63 . The locking arm  70  pivots on the locking arm bolt when the cam surface  62  is forced against the cam appendage  72 . The cam surface  62  forces the cam appendage  72  against the support tube  18 . The spring appendage  74  includes a bore  80  for receiving a spring  82 . The spring  82  is disposed between the spring appendage  74  and the bottom of the fence beam  22 . When the cam surface  62  is pivoted away from the cam appendage  72 , the spring  82  forces the locking arm to a released position. This allows the fence  10  to slide freely upon the support tube  18 . Conversely, when handle  54  is pressed down, cam surface  62  engages cam appendage  72  forcing it against support tube  18  to lock the fence  10  with respect to support tube  18 . It should be appreciated that bracket  63  is illustrated with opposing walls  64  and  84 , but that it could have only one wall. 
   The lockdown assembly  24  also includes a micro adjust saddle  86 . The saddle  86  includes a generally u-shaped bracket  88  which fits over the support tube  18 . The bracket  88  can slide along the support tube  18  to allow general positioning of the fence  10  on the tablesaw  14 . A spring loaded quick lock lever  90  is provided to quickly lock the saddle  86  in position on tablesaw  14 . 
   In the disclosed embodiment, the lever  90  has a threaded shaft  92  which threads into internally threaded aperture  94  to engage a flexible strip  96 , see  FIGS. 3 and 6 . The shaft  92  is threaded through a plate  98  which is attached to the saddle  86  to provide additional material for receiving the shaft  92 . 
   The saddle  86  is mounted to the fence  10  through mounting ears  100 . Each of the mounting ears  100  have a mounting aperture  102  which receives threaded shaft  66 . As illustrated, the mounting ears  100  are spaced apart so that the opposing walls  64  and  84  of bracket  63  fit between ears  100 . 
   Micro adjustment shaft  104  mounts the saddle  86  to the fence  10 . In particular, the shaft  104  is inserted through one ear  100  threaded through the arm bolt  66  and through the other ear  100 . A knob  106  is attached to one end of the shaft  104 . The knob  106  and nut  108  engage the ears  100  so that when knob  106  is rotated, the fence beam  22  is moved with respect to the saddle  86  and with respect to the saw blade  14 . In this way, the fence beam can be precisely adjusted with respect to the saw blade  14 . The adjustment precision is dependent upon the threads per inch of the shaft  104 . In the preferred embodiment there are  16  threads per inch. One full turn of the knob  106  moves the fence beam  22  1/16″ with respect to the saw blade  14 . One half turn moves the beam  22  1/32″, ¼ turn 1/64 inch, ⅛ turn 1/128″. As will be appreciated, very fine micro adjustments are obtained. 
   As illustrated in  FIG. 2 , the saddle  86  has an opening  110  which receives the cam appendage  72 . Once the precise location of fence beam  22  is obtained, the main fence lock  54  can be depressed to engage cam appendage  72  against the support tube  18 . With the cam appendage  72  engaged against the support tube  18 , the fence  10  is locked in place. 
   With reference to  FIG. 2 , a flat head machine bolt  112  is provided in the side wall  49  opposite the cam appendage  72  to support the saddle  88 . 
   With respect to  FIGS. 1 ,  2 ,  3  and  6 , a lens  114  is affixed to the fence head  26 . The lens  114  includes a score  116  or sight mark that can be used to identify the position of the fence  10  on the support tube  18  if the support tube  18  is incrementally marked. In the preferred embodiment, a ruler  118  is affixed to the support tube  18  to facilitate accurate positioning. 
   In use, the fence  10  of the present invention is mounted on the support tube  18  by placing saddle  86  over support tube  18  and placing mounting member  48  upon the support tube  18 . The fence can then be moved along the longitudinal axis of support tube  18  to either increase or decrease the distance between the side of the fence beam  22  and the tool  12 . With reference to  FIG. 1 , the fence  10  can be moved across the work surface  16  and its distance from the saw blade  12  can be determined by the ruler  114  mounted to the support tube  18 . Once the fence is the appropriate distance from blade  12 , the quick lock lever  90  is rotated to thread the threaded shaft  92  into engagement with the support tube  18 . This can be seen in  FIGS. 4 and 5 . As disclosed, there is a flexible strip  96  which facilitates the locking of the fence  10  to the support beam  18  and prevents marring of the support beam  18 . 
   Once the general placement is determined, the distance between the saw blade and fence can be fine tuned by rotating knob  106  on micro adjustment shaft  104 . As shown in  FIG. 6 , rotation of the knob  106  will move the fence beam  22  in very small increments with respect to the blade  12 . Once the fence is properly aligned, then the main fence lock  24  can be depressed engaging the cam appendage into engagement with the support tube  18  to finally lock the fence in place. See  FIG. 7 . It should be understood, that the fence would function without the need for the main fence lock, but there could be the potential for movement of the fine adjustment by inadvertent engagement with knob  106 . Further, the main fence lock  24  provides more substantial locking of the fence with respect to the support beam. 
   As also will be understood by the above description, the fences  20  can be readily replaced by tapping the ends of the fences in the direction of the enlarged end  44 . When the enlarged ends  44  are in position over the heads  32 , the fences can be removed and replaced with either new fences or jigs etc. for whatever operation is being conducted by the user. 
   With reference to  FIG. 11 , the fence assembly of the present invention is shown on a combination tablesaw and router table  120 . The combination tablesaw and router table  120  has a saw blade  12  and a router  122 . The fence assembly  10  is especially useful for this type of table mounted tool because both sides of beam  22  can be used, one side  124  for guiding a workpiece to the saw blade  12  and the other side  126  for guiding a workpiece to the router  122 . The fence assembly  10  is also especially suited for this application because an accessory tool or jig  130  can be quickly mounted to either side  124  or  126 ; in this illustration it is mounted to side  126 . 
   As illustrated in  FIGS. 11 and 12 , the accessory tool  130  is a split type fence  132 . The split type fence  132  has a base  134  and two sliding guides  136  and  138 . The sliding guides  136  and  138  can be slid with respect to one another to form a gap  140 . The gap  140  receives the cutter blade of the router  122  so that when a workpiece is slid along the guides  136  and  138 , the cutter blade can precisely cut the workpiece. 
   With reference to  FIG. 12 , the disclosed method of mounting the guide  136  to the base  134  is illustrated. The base  134  has a slot  142  which receives a slide  144  which is mounted to the guide  136  by a screw  146 . It should be appreciated that the base  134  is mounted to the beam  22  with the fasteners disclosed in the present invention. In the preferred embodiment, the fasteners used are the studs  28  and keyhole slot plate  40 . 
   Referring now to  FIG. 13 , a fixture base  150  is disclosed. Base  150  has a plurality of channels  152 ,  154 ,  156  and  158  which receive fasteners of various types to which jigs  158  of various type can be mounted. 
   A fence mounting slot  160  is provided for receipt of a fastener to fasten the fixture base  150  to the fence beam  22 . In the preferred embodiment, the slot  160  receives a keyhole plate  40 . The plate  40  is fastened into slot  160  with screws. In this way, the base  150  can be quickly and easily mounted to the beam  22  over studs  28  without the use of tools. 
   With reference to  FIG. 14 , a still further accessory tool  162  is disclosed. Accessory tool  162  is an extended fence for handling larger workpieces. As with the fence face, the extended fence  162  has a cavity  164  for receipt of a plate  40 . The plate  40  is then mounted to the fence beam  22  by the studs  28 . 
   It should be appreciated by those of ordinary skill in the art that the above disclosed accessory tools are merely an example of various accessories which could be used. It is not the intention of applicant to in any way limit patent protection to the specific examples above, but to show the variety of accessories that can be used. The fence assembly  10  of the present invention is virtually a universal base for any number of attachments. 
   The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. 
   Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that reference numerals are merely for convenience and are not to be in any way limiting and that the invention may be practiced otherwise than as specifically described.

Technology Classification (CPC): 8