Abstract:
A digital fence positioning system is mounted to a preexisting table saw by clamping the digital fence positioning system directly to the fence rail. A clamping device includes two clamps positioned near opposite ends of a guide rail for a fence. Each clamp has top and bottom portions that can be secured to encompass a circular surface of the guide rail.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation-in-part of application Ser. No. 09/578,806 filed May 24, 2000 titled “Automated Fence Control Coupling System” which is hereby incorporated by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates to saws. In particular, the invention involves an after-market accessory for mounting a digital fence positioning system on a table saw.  
         BACKGROUND OF THE INVENTION  
         [0003]    Table saws are often equipped with a moveable fence to allow the operator to set desired cut dimensions. Table saw fences typically are moveable along a guide rail that is bolted along one side of the table saw. An operator can slide the fence back and forth along the guide rail and then lock the fence in place by means of a locking handle. Many such table saws are sold in a design that requires manual adjustment of the fence.  
           [0004]    Sometimes it is desirable to use a table saw in an automated or semi-automated capacity. Digital positioning systems are available for adding onto a table saw that has a manually operable fence. After market automated fence positioning systems may be cumbersome to install. Some positioning systems require replacement of the fence and the rail. Such an overhaul procedure is time consuming and may require a relatively high level of mechanical skill.  
           [0005]    Another type of automated fence positioning system is designed for mounting on a preexisting rail, and for use with the preexisting fence and positioning clamp. This approach requires the purchaser to bolt the positioning system to the table via brackets. Mounting of the positioning system on the saw can be challenging because it is critical that the positioner guide rail be aligned precisely in parallel with the preexisting fence rail. It can be difficult and time consuming to achieve proper alignment of the positioning guide and the fence rail.  
           [0006]    Another problem with prior automated fence positioning systems is that different table saws have different table and bolt configurations so that one bracket design may not be universally functional to mount the system on different saw configurations.  
         SUMMARY OF THE INVENTION  
         [0007]    The invention provides a system and method for adding an automated fence positioning system to a preexisting table saw. The fence positioning system operates with a preexisting fence and associated guide rail for directing movement of the fence. The positioning system includes a controller mounted in a fixed position on a separate positioner guide rail or channeling member, and a fence mover or positioner that is connected to the fence. The positioner moves along the positioner guide rail, and is operated by the controller. The positioner guide rail is directly clamped to opposing ends of the preexisting fence rail. The direct clamping mechanism allows the rails to be aligned easily in a parallel relationship so that the fence positioning system functions properly.  
       
    
    
     DESCRIPTION OF THE FIGURES  
       [0008]    [0008]FIG. 1 is a perspective view of a table saw with an after-market automated fence positioning system.  
         [0009]    [0009]FIG. 2 is a perspective view of a table saw, according to a preferred embodiment of the invention, showing a positioner guide rail clamped directly to a preexisting fence rail.  
         [0010]    [0010]FIG. 3 is a side view of the table saw shown in FIG. 2.  
         [0011]    [0011]FIG. 4 is a close-up view of the clamp and rails shown in FIG. 3. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0012]    The invention provides a simplified system and method for adding an automated fence positioning system to a preexisting table saw. In particular, the invention allows a person to mount a digital fence positioning device to a table saw without dismantling the table saw, and without encountering significant difficulties aligning the fence positioner with the preexisting fence rail. The invention enables a person having less mechanical skill then was previously required, to install a fence positioning device.  
         [0013]    [0013]FIG. 1 shows a table saw and automated fence-positioning device in the prior art. FIGS.  2 - 4  show details of an improved mechanism, according to a preferred embodiment of the invention, for mounting an automated fence-positioning device on a table saw. In particular, FIGS.  2 - 4  show a pair of clamps that directly join the fence controller device to the preexisting rail for the fence.  
         [0014]    In FIG. 1, table  20  employs circular saw  22  to cut wood, plastic, metal, composite, or other material in direction  23 . Fence  24  is moveable back and forth in direction  25  along fence rail  26 . Fence rail  26  is connected to table  20  by cross supports  27 . An accessory device is added to table saw  20  to control automatically the position of fence  24  in direction  25 , thus determining a dimension to cut lumber. The fence controller  29  may include a computer and a keyboard mounted on or near table  20 . A drive motor and amplifier are contained in housing  30  which is connected in a fixed location to positioner guide rail  32 . Positioner guide rail  32  is connected to table  20  via brackets  34  that mount on to cross supports  27 . Fence positioner  36  is rigidly connected to fence  24 , and is moveable, per instruction from controller  30 , along positioner guide rail  32 .  
         [0015]    A number of different mechanisms may be used to move positioner  36  along positioner guide rail  32 . For example, positioner  36  may be connected to a chain (not shown) inside positioner guide rail  32 . The chain may be driven by one or more sprockets mounted on an axle which may in turn be driven by an electric motor. Alternatively, positioner  36  may be connected to a threaded rod inside positioner guide rail  32 . An electric motor may be connected to controller  30  for rotating the threaded rod, thereby causing positioner  36  to move in direction  25  along positioner guide rail  32 , and causing corresponding positioning of fence  24  on table saw  20 . For example, see U.S. Pat. Nos. 5,524,514, 5,444,635, and No. 4,791,757 which each disclose drive mechanisms for moving a positioner along a rail. Each of these U.S. patents is hereby incorporated by reference. Cable  38  is a pneumatic line attached to a cylinder and solenoid mechanism which functions to lock or unlock the fence position.  
         [0016]    Controller  30  may include a computer that is capable of memorizing one or more cut lists, for example, according to U.S. Pat. No. 5,444,635 which is hereby incorporated by reference. The computer may also be capable of optimizing a cut routine based on a desired cut list and information concerning available raw materials entered in the computer. Keypad  29  may be used to input data into the computer, and may also be used to carry out calculations. The computer may also control the drive mechanism that causes movement of fence positioner  36  along positioner guide rail  32 . The controller may also be capable of memorizing common cut lengths and carrying out movement of the fence to a pre-programmed position in response to manual contact of a single key on keypad  29 .  
         [0017]    [0017]FIG. 2 shows a preferred embodiment of the invention in which many of the elements of table saw  20  are the same as shown in FIG. 1. In FIG. 2 positioner guide rail  40  is connected directly to fence rail  26  via clamps  42   a  and  42   b . Importantly, clamps  42   a  and  42   b  are connected to fence rail  26  at extreme opposite end portions of fence rail  26  so as not to interfere with movement of fence  24  in normal operation.  
         [0018]    As shown in FIGS.  2 - 4 , clamps  42   a  and  42   b  are configured to extend in a downwardly diagonal orientation so that the fence controller device is ultimately positioned outward and down slightly from table  20  and fence rail  26 .  
         [0019]    [0019]FIG. 3 shows a side view of the table in FIG. 2. FIG. 4 shows a portion of FIG. 3 expanded to focus on clamp  42   a  for connecting positioner guide rail  32  directly to fence rail  26 . Clamp  42   a  has lower portion  50  that is bolted to upper portion  52 . Bolt holes are shown in dashed lines. Specifically, bolt holes  54   a  and  54   b  are provided for coupling lower portion  50  of clamp  42   a  to positioner guide rail  32 . Bolt holes  56   a  and  56   b  are provided for coupling upper portion  52  of clamp  42   a  to lower portion  50 . When the digital fence controller device is properly installed, interface line  60  between upper portion  52  and lower portion  50  of clamp  42   a  is substantially horizontal or parallel to the surface of table  20 .  
         [0020]    Clamps  42   a  and  42   b  allow a person having minimal mechanical skill easily to mount a digital fence controlling system without dismantling preexisting hardware. Precise alignment of the positioner guide rail in parallel with the fence rail is achieved simply by bolting the clamps on to opposite ends of the fence rail.  
         [0021]    Although the invention has been disclosed in its preferred forms, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. Singular terms used herein do not preclude the use of more than one of the associated element, and embodiments utilizing more than one of a particular element are within the spirit and scope of the invention. Applicant regards the subject matter of his invention to include all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims define certain combinations and subcombinations of features, functions, elements, and/or properties that are regarded as novel and nonobvious. Other combinations and subcombinations may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such claims, whether they are broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of applicant&#39;s invention.