Abstract:
A fence assembly for a table saw includes a track for mounting on one edge of the table saw perpendicular to a slot in the table top of the saw and a blade in the slot, a carriage slidable on the track, a fence rotatable on the carriage for defining a straight guide edge at any angle from 0 to 90° with respect to the blade, and a guide plate above the fence with indicia thereon for accurately positioning the fence. A pair of bolts extend upwardly from the carriage through arcuate slots in the fence to the guide plate for slidably supporting the fence. Knobs on the top of the bolts are used to releasably clamp the fence between the guide plate and the carriage.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a fence assembly for use on a table saw.  
           [0003]    Specifically, the invention relates to a fence assembly for use on a table saw, which includes a rectangular table top and a slot extending longitudinally of the table top for receiving a circular saw blade. While the fence assembly disclosed herein was designed specifically for use with a table saw of the type disclosed in the inventor&#39;s Canadian Patent Application Serial No. 2,119,279, filed Mar. 16, 1994, it will be appreciated that the assembly can be used on other table saws with fixed or movable blades.  
           [0004]    2. Discussion of the Prior Art  
           [0005]    Fences for table saws are described in U.S. Pat. Nos. 2,032,976, which issued to R. L. Carter on Mar. 3, 1936; U.S. Pat. No. 2,064,607, which issued to J. A. Hirtz, Sr. on Dec. 15, 1936; U.S. Pat. No. 2,310,813, which issued to G. J. Sellmeyer on Feb. 9, 1943; U.S. Pat. No. 2,954,062, which issued to E. Leitchner on Sep. 27, 1960; U.S. Pat. No. 2,968,325, which issued to T. S. Wandvik on Jan. 17, 1961; U.S. Pat. No. 3,465,797, which issued to M. R. Kimber on Sep. 9, 1969; U.S. Pat. No. 4,265,154, which issued to W. A. Batson on May 5, 1981; U.S. Pat. No. 4,455,907, which issued to A. L. Bassett on Jun. 26, 1984; U.S. Pat. No. 5,038,485, which issued to J. S. Ducate, Sr., on Aug. 13, 1991; U.S. Pat. No. 5,181,448, which issued to D. A. Terpstra on Jan. 26, 1993 and U.S. Pat. No. 5,611,525, which issued to W. M. Bishop on Mar. 18, 1997. In general, the patented fences are complicated and expensive to manufacture. The more recent devices of this type require custom metal castings, and machined elements.  
         GENERAL DESCRIPTION OF THE INVENTION  
         [0006]    The object of the present invention is to provide a relatively simple fence assembly for use with a table saw which is easy to produce and consequently inexpensive. The main components of the present invention are formed of simple aluminum extrusions or thin, bent aluminum sheets which lend themselves to mass production.  
           [0007]    Another object of the invention is to provide a fence assembly for use with a table saw which is easy to use, i.e. easy to move along the edge of a saw table and readily rotated to change the angle of the fence with respect to a saw blade.  
           [0008]    Accordingly, the invention relates to a fence assembly for use on a table saw including a table top, a slot extending longitudinally of the table top, and a blade extending through said slot for cutting a workpiece, said assembly comprising:  
           [0009]    (a) a track for mounting on one side edge of said table top perpendicular to said slot;  
           [0010]    (b) a carriage slidable on said track for movement along said one side edge;  
           [0011]    (c) a fence slidable on said carriage for movement therewith, said fence including  
           [0012]    (i) a top plate for overlapping the table top of the saw;  
           [0013]    (ii) a straight edge on one side of said top plate for guiding a workpiece on the table top;  
           [0014]    (iii) a first arcuate slot in said top plate, a line through the ends of the first slot being parallel to said straight edge; and  
           [0015]    (iv) second arcuate slots intersecting said first arcuate slot on eithr side of the center thereof;  
           [0016]    (d) a guide plate above said top plate for rectilinear movement with said carriage along said one side of the table top;  
           [0017]    (e) guide posts extending upwardly from said carriage through said first slot and said guide plate permitting rotation of the fence between said carriage and said guide plate whereby the fence can be rotated through 180° around vertical axes defined by said guide posts between positions in which said straight edge is parallel to said slot in the table top on either side of the slot. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    The invention is described in greater detail hereinafter with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, and wherein:  
         [0019]    [0019]FIG. 1 is an isometric view of a table saw with a fence assembly in accordance with the invention mounted thereon;  
         [0020]    [0020]FIG. 2 is a perspective view of the fence assembly from above and one end, with parts omitted;  
         [0021]    [0021]FIG. 3 is a front view of the fence assembly;  
         [0022]    [0022]FIG. 4 is an end view of the fence assembly as seen from the right of FIG. 1;  
         [0023]    [0023]FIG. 5 is an exploded, isometric view of the fence assembly with parts omitted; and  
         [0024]    [0024]FIG. 6 is a schematic top view of the fence assembly showing the fence in a variety of positions.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    With reference to FIG. 1, the fence assembly, which is generally indicated at  1  was originally designed for use on a table saw disclosed in the inventor&#39;s U.S. Pat. No. 5,842,400, issued Dec. 1, 1998. The table saw includes a table  2 , the base of which is defined by a frame  3  including four legs  4 , longitudinally extending top and bottom bars  5  and  6 , respectively, and cross braces  7 . A table top  8  is mounted on the frame  3 . A slot  9  extends longitudinally through the top  8  along substantially the entire length thereof. A rail  10  (one shown) extends longitudinally along each side of the frame  2  beneath the table top  8  between the legs  4 . A cylindrical bushing  12  is slidably mounted on each rail  10  for slidably supporting a carriage and circular saw assembly (not shown) beneath the table top  8 .  
         [0026]    The saw assembly includes a blade  14  extending through the slot  9 . The carriage and saw assembly are caused to move along the rails  10  using a splitter plate or arm  15  extending upwardly through the slot  9 . A tubular arm  16  extends forwardly from the top end of the arm  15 , and a handle  17  with a trigger  18  are mounted on the outer free end of the arm  16 . As described in U.S. Pat. No. 5,842,400, the handle  17  and the trigger  18  are used for manual starting and stopping of the saw, and for moving the carriage and saw assembly longitudinally of the table. During sawing, the splitter plate  15  maintaines the sides of a slot cut in a wooden workpiece apart.  
         [0027]    The fence assembly I includes a tubular track  20  mounted on one side edge  21  (in this case the front end) of the table top  8 . The track  20 , which is a simple channel member formed from an aluminum extrusion, slidably supports a carriage  23  (FIGS.  3  to  5 ), a fence  24  and a guide plate  25 . As best shown in FIG. 4, the track  20  is generally rectangular in cross section and extends across the entire front edge  21  of the table top  8 . The track  20  is mounted beneath the edge  21  of the table top  8  by means of an inverted L-shaped bracket  26 , which is attached to the table top by screws  27  (one shown). The track  20  is connected to the bracket  26  by bolts  28  and nuts  29  (one shown—FIG. 4).  
         [0028]    A vertical partition  30  extends the length of the interior of the track  20 . A slot  32  (FIG. 5) in the outer side of the track  20  opens into a longitudinally extending channel  34 , which receives a generally C-shaped latch  35 , the open side of which faces outwardly. Vertical movement of the latch  35  is prevented by inwardly extending flanges  37  at the top and bottom of the slot  32 . The carriage  23 , which is merely a strip of aluminum with an inverted L-shaped cross section, is connected to the latch  35  by a carriage bolt  38  and an internally threaded knob  39 . The bolt  38  extends through the latch  35 , a plastic slide  40  on the inside surface of the vertical arm  41  of the carriage  23  and the vertical arm  41  itself into a threaded cavity (not shown) in the knob  39 . By loosening the knob  39 , the carriage  23  is released from a latched position for sliding along the track  20 . By tightening the knob  39 , the slide  40  is pressed against the outer side of the track  20  to fix the carriage  23  in one position. A second plastic slide  42  is provided on the bottom surface of the horizontal top arm  43  of the carriage  23  for riding on the top wall  44  of the track  20 .  
         [0029]    As mentioned above, the fence  24  is mounted on the carriage  23  for movement therewith along the side edge  21  of the table top  8 . The fence  24  is defined by a generally rectangular plate  45  with tapering arms  46  integral with and extending outwardly from the ends thereof, and an elongated straight edge  47 , which has an L-shaped cross section, connected to one straight side  48  of the plate  45 . In this connection, it will be noted that one straight side of each arm  46  defines a continuation of the straight side of the plate  45 . An opening  49  is provided in the center of the straight edge  47  for admitting the saw blade  14  when making a crosscut perpendicular to the blade, i.e. with the fence in the position shown in FIG. 1. The fence  24  is connected to the slide  23  for movement therewith along the track  20  by a pair of carriage bolts  50  extending upwardly through the horizontal top arm  43  of the carriage  23 .  
         [0030]    Each bolt  50  extends upwardly through a pair of washers  51 , the plate  45  of the fence  24 , another washer  53 , a sleeve  54  and the guide plate  25  into an internally threaded knob  55 . With this arrangement, (as shown in FIGS. 3 and 4), the plate  45  is spaced a short distance apart from the table top  8 . Thus, there is no resistance form the table top  8  to rotation of the plate  45 . In order to permit rotation of the fence  24  with respect to the edge  21  of the table top  8 , a generally semicircular slot  56  is provided in the plate  46  of the fence. The ends  57  of the slot  56  are near the straight edge  49  of the plate  46  (not shown). A line through the ends  57  would be parallel to the edge  49  and the straight edge  48 . The length and curvature of the slot  56 , and the spacing between the bolts  50  are such that the fence  24  can rotate freely relative to the slide  23  without sticking or bending. Short arcuate slots  59  (FIGS. 1, 2 and  6 ) extending from proximate the outer corners of the plate  45  intersect the slot  56  at approximately one-third the distance from either end thereof. The slots  56  and  59  permit rotation of the straight edge  47  of the fence  24  from a position perpendicular to the slot  9  and the blade  14  (FIG. 1, and phantom outline in FIG. 6) to a position parallel to the, blade  14  (shown in solid outline in FIG. 6) on either side of the blade. It will be appreciated that in the absence of the slots  59 , it would not be possible to position the straight edge parallel to the slot  9  in the saw table top  8 .  
         [0031]    A pointer  62  is provided on one side of the guide plate  25  for alignment with indicia or lines  63  in the form of straight grooves or painted marks on the plate. The indicia  63  provide an indication of the angle between the straight edge  47  and the blade  14 . A second notched pointer  65  is provided on the opposite side of the guide plate  25  for supporting the other side of the plate on the top plate  45  of the fence  24 .  
         [0032]    During use, with the straight edge  47  parallel to the edge  21  of the table top  8  (FIG. 1), the assembly is used to position a wooden workpiece (not shown) perpendicular to the slot  9  and the blade  14 , e.g. for making a crosscut in the workpiece. In such position, the pointer  62  is aligned with the central line  63 , indicating that the straight edge  47  is perpendicular to the blade  14 . By loosening the knobs  55 , the fence  24  is released for rotation to change the angle of the fence with respect to the plane of the blade  14  for making an angle cut.  
         [0033]    When the straight edge  47  is to be parallel to the blade  14 , the knobs  55  are loosened and the fence  24  is rotated. When the trailing bolt  50  (in the direction of fence rotation) reaches one of the slots  59 , the bolt enters the slot, so that the plate  45  can continue to rotate to a position (shown in solid lines in FIG. 6) in which the straight edge  47  is perpendicular to the side edge  21  of the table top  8  and parallel to the slot  9  and the saw blade  14 . In order to adjust the lateral spacing between the straight edge  47  and the blade  14 , the knob  39  is loosened and the carriage  23  is slid along the track  20  until the fence  24  reaches the desired position, when the knob  39  is again tightened.