Abstract:
Extension rails for table saws are disclosed. Some of the disclosed extension rails can be attached to a table saw without a user having to manipulate a lever or knob. Extension rails particularly relevant to portable table saws such as jobsite and bench-top table saws are disclosed, including extension rails that can provide 48″ or more of cutting capacity on jobsite and/or bench-top table saws. A method of attaching extension rails to a table saw is disclosed that does not require the use of a tool or the manipulation of a knob or clamp.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of and priority from U.S. Provisional Patent Application Ser. No. 61/973,044, filed Mar. 31, 2014, which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present specification relates to table saws, and particularly, to extension rails for table saws. 
       BACKGROUND 
       [0003]    A table saw is a power tool used to cut a work piece, such as a piece of wood, to a desired size or shape. A table saw includes a work surface or table and a circular blade extending up through the table. A person uses a table saw by placing a work piece on the table and feeding it into contact with the spinning blade to cut the work piece to a desired size. 
         [0004]    The table saw is one of the most basic machines used in woodworking. For example, table saws are used to make furniture and cabinetry, to install hardwood flooring, to cut material for countertops, to cut plywood panels for roofing and walls, to make pallets and crates, and for many more projects and tasks. 
         [0005]    Table saws come in various sizes ranging from large, stationary, industrial table saws, to small, lightweight, portable table saws. Larger table saws are sometimes called cabinet saws, mid-sized table saws are sometimes called contractor saws or hybrid saws, and smaller table saws are sometimes called portable, jobsite, or bench-top table saws. The larger table saws include induction motors and typically weigh well over 100 pounds. The smaller, portable table saws are typically small and light enough to be transported in the back of a pick-up truck, and they often have stands with wheels so they can be moved around a jobsite or workspace. The smaller table saws have universal motors and weigh less than 100 pounds. For example, jobsite saws weigh approximately 60 to 80 pounds, and the smallest bench-top saws weigh approximately 30 to 40 pounds. 
         [0006]    This document describes extension tables and rails that can be used with all types of table saws. The extension tables and rails described herein may be particularly relevant to portable table saws such as jobsite table saws. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  shows a table saw. 
           [0008]      FIG. 2  shows a table saw with rails extended. 
           [0009]      FIG. 3  shows a table saw with extension rails. 
           [0010]      FIG. 4  shows a table saw and extension rails ready to be attached to the table saw. 
           [0011]      FIG. 5  shows a latch plate and socket associated with a rail and an extension rail. 
           [0012]      FIG. 6  shows a rail and extension rail coupled together by a latch plate and socket. 
           [0013]      FIG. 7  shows a rail with a latch plate and spring. 
           [0014]      FIG. 8  shows a rail and a rail extension with ball and socket guides. 
           [0015]      FIG. 9  shows a rail and a rail extension, with the rail extension at an angle relative to the rail, and with a ball entering a socket. 
           [0016]      FIG. 10  shows a rail and a rail extension, with the rail and rail extension collinear and with a ball in a socket. 
           [0017]      FIG. 11  shows an alternative embodiment with two latch plates extending from an extension rail. 
           [0018]      FIG. 12  shows the embodiment of  FIG. 11  with the latch plates inserted into a rail. 
           [0019]      FIG. 13  shows an alternative embodiment with a clamping mechanism configured to secure a rail and extension rail together. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  shows a table saw  10 . The table saw includes a table  12  with an opening  14  and an insert  16  in the opening. A blade  18  extends up through a slot  20  in the insert. A housing  22  supports the table and a motor is within the housing. The motor is operably connected to the blade to drive or spin the blade. To use the table saw, a user places a work piece on the table and slides it into contact with the spinning blade to make a cut. 
         [0021]    Typically a user of a table saw guides the work piece past the blade with a fence, such as fence  30  in  FIG. 1 . The fence mounts to the top of the table saw and provides a fixed reference surface relative to the blade. The user can slide the work piece against and along the fence to make a cut. The fence helps keep the work piece moving in a straight path without shifting or rotating, and therefore, helps produce a straight cut. The fence can be positioned at various positions relative to the blade so that a work piece can be cut to different dimensions. 
         [0022]    The fence typically clamps to a rail running along the front edge of the table saw, such as front rail  32  in  FIG. 1 , and the fence can be locked or clamped anywhere along the rail. The fence may also rest on or clamp to a rail running along the rear of a table saw, such as rear rail  34  in  FIG. 1 . Various fences are described in U.S. Provisional Patent Application Ser. No. 61/892,237, titled “Fences for Table Saws,” filed Oct. 17, 2013, which is incorporated herein by reference. 
         [0023]    The length of the rail along the front of the saw determines how far the fence can be positioned from the blade, and therefore, the largest dimension that can be cut on the saw using the fence. This may be called the cutting capacity or rip capacity of the saw. Some table saws include rails sufficiently long to provide 36 inches of cutting capacity—in other words, the face of the fence nearest the blade can be positioned 36 inches away from the blade so a work piece can be cut to 36 inches wide, and the front and rear rails are long enough to support the fence in that position. Other table saws include rails with 52 inches of cutting capacity. Saws with these cutting capacities are typically stationary saws called cabinet saws or contractor saws. Smaller, portable table saws, such as jobsite or bench-top saws, typically provide anywhere from 18 inches to about 30 inches of cutting capacity. 
         [0024]    In smaller, portable table saws, the rails may move or telescope out to provide increased cutting capacity. In table saw  10 , front rail  32  and rear rail  34  are attached to table  12  in such a way that they can move to the right to provide increased cutting capacity.  FIG. 2  shows table saw  10  with front rail  32  and a rear rail  34  moved or extended to the right side. An extension table  36  extends between the right, distal ends of the front and rear rails and is connected to both rails. The extension table provides an additional support surface for work pieces, especially when the rails are extended. Extension table  36  can be connected to the front and rear rails in many ways, for example, by screws which thread into sockets on the front and rear rails, or by screws which thread into clamping plates that clamp against surfaces on the front and rear rails when the screws are tightened. In  FIG. 2 , fence  30  is positioned over extension table  36 . 
         [0025]    In smaller, portable table saws, the rails are typically sized so that they do not extend substantially beyond the perimeter of the table when the rails are retracted. This minimizes the size and weight of the saw and helps maximize the saw&#39;s portability, but limits the saw&#39;s cutting capacity when using the fence. To increase the cutting capacity, so that a user can cut a large sheet of plywood, for example, extension rails can be used.  FIG. 3  shows a table saw  10  with a front extension rail  50  and a rear extension rail  52  coupled to the ends of front and rear rails  32  and  34 , respectively, to increase the cutting capacity of the saw. An auxiliary extension table  54  extends between and is connected to the right ends of the front and rear extension rails to provide an additional support surface for work pieces. Front and rear extension rails  50  and  52  can be sized to provide significant additional cutting capacity. For example, the extension rails may be sized to provide  48  inches of cutting capacity to the right of the blade. 
         [0026]    Extension rails  50  and  52  may connect to front and rear rails  32  and  34  in various ways.  FIG. 4  shows front extension rail  50  with a latch plate  56  extending out from the left end of the extension rail. Latch plate  56  is configured to fit in a socket  58  in the right end of front extension rail  32 . Rear extension rail  52  has a similar latch plate  60 , and rear rail  34  has a similar socket  62 . A user simply inserts latch plates  56  and  60  into sockets  58  and  62  while holding the rails at somewhat of an angle, as shown generally in  FIG. 4 , and then lowers the rails until they are generally horizontal and in line with front and rear rails  32  and  34 . Alternatively, one or both latch plates could extend from the front and rear rails, and one or both sockets could be positioned in the extension rails. 
         [0027]      FIG. 5  shows an enlarged view of front extension rail  50  with latch plate  56  and front rail  32  with socket  58 .  FIG. 6  shows front rail  32  and front extension rail  50  joined together with latch plate  56  in socket  58 . In  FIG. 6 , the rails are cut in cross-section so that latch plate  56  is visible. 
         [0028]    Latch plate  56  is held in front extension rail  50  by a pin  64  that is pressed through a hole  66  in the latch plate, as shown in  FIG. 6 , and through holes in the rail, such as hole  68  shown in  FIG. 5 . Latch plate  56  can pivot around pin  64 , and a spring  70  (shown in  FIG. 7 ) biases the latch plate up. In  FIG. 7 , the rails are cut in cross-section so that latch plate  56  and spring  70  are visible.  FIG. 7  shows the spring  70  adjacent what may be thought of as the back side of latch plate  56 . Spring  70  includes a loop or coil portion  72  that extends over and around pin  64 . A first spring arm  74  extends out from coil portion  72 , and the tip of the first spring arm extends through a hole  76  in latch plate  56 . A second spring arm  78  also extends out from coil portion  72  in a direction generally opposite the first spring arm, and the tip of the second spring arm rests against an inside top surface of front extension rail  50 . In this manner spring  70  biases latch plate  56  up. 
         [0029]    Front rail  32  includes a pin  80  that extends across the interior of the front rail. Pin  80  is pressed into holes in front rail  32  to secure the pin in place. Latch plate  56  hooks behind pin  80 , as shown in  FIG. 6 , to connect front extension rail  50  to front rail  32 . More specifically, latch plate  56  includes a distal end  82  sized and shaped to fit under pin  80 . Distal end  82  also has a generally pointed shape to facilitate the insertion of the latch plate into socket  58 . When front extension rail  50  is unconnected to front rail  32 , distal end  82  extends above the top of the front extension rail, as shown in  FIGS. 5 and 7 . With this configuration, a user tilts the front extension rail relative to front rail  32  and inserts latch plate  56  into socket  58  so that distal end  82  passes beyond and under pin  80 . The top edge of the end of the front extension rail adjacent latch plate  56  includes a cutout  84  (labeled in  FIG. 6 ) that allows the front extension rail to tilt relative to front rail  32  as latch plate  56  is inserted into socket  58 . Cutout  84  is sized so that the edge of the cutout contacts the end of front rail  32  when distal end  82  of latch plate  56  has passed under pin  80 . Rear rail  34 , rear extension rail  52 , and rear latch plate  60  are configured similarly. 
         [0030]    As stated previously, to connect the extension rails to the front and rear rails on the saw, a person holds the extension rails at an angle relative to the front and rear rails so that the distal ends of the latch plates fit into the respective sockets in the front and rear rails. The person then lowers the extension rails until they are in line with the front and rear rails. Gravity holds the extension rails down and hooks such as hook  84  prevent the extension rails from shifting horizontally to the right. A person reverses these steps to disconnect the extension rails, i.e., a user grasps the ends of the extension rails that are distal from the saw, pivots the extension rails up, and slides the latch plates out of the sockets to detach the extension rails from the table saw. 
         [0031]    When front and rear extension rails  50  and  52  are attached to front and rear rails  32  and  34 , respectively, the configuration of latch plates  56  and  60  transfers the weight of the extension rails to the main rails. When a person lowers the extension rails so that they are in line with the main rails, an upper edge  86  on the distal end  82  of latch plate  56  contacts the inside upper surface of front rail  32  at point  88 , as shown in  FIG. 6 . That contact causes distal end  82  of latch plate  56  to pivot down around pin  64  against spring  70 . Latch plate  56  is configured so that when distal end  82  pivots down, a bottom edge  90  of latch plate  56  contacts the inside bottom surface of front rail  32  and front extension rail  52  at point  92  generally over the joint between the main and extension rails, as shown in  FIG. 6 . At the same time, rear end  94  of latch plate  56  pivots up around pin  64  until a rear upper edge  96  contacts the inside upper surface of extension rail  50  at point  98 . These three contact points— 88 ,  90  and  98 —stabilize the front extension rail relative to the front rail and transfer the weight of the front extension rail to the front rail. Gravity pulls the extension rails down and holds the rails in place. Additionally, pins  64  and  80  may flex slightly when front extension rail  50  is lowered into place, and the flexing of the pins provides at least some moderate force to help hold the rails together. The rear rail is secured and supported similarly. 
         [0032]      FIGS. 8 ,  9  and  10  show ball and socket pairs that can be used to provide front-to-back and rotational alignment of the rails, and they can also contribute to vertical alignment. Balls  100  and  102  in front extension rail  50  are configured to fit into sockets  104  and  106 , respectively, in front rail  32 . Balls  100  and  102  can be press fit into channels or sockets in the extension rail. Of course, other means could be implemented to provide the front-to-back and rotational alignment of the rails, and guides of various shapes could be used in place of balls  100  and  102 . 
         [0033]    Front and rear rails  32  and  34  may be extruded with the sockets and surfaces described above. Front extension rail  50  and rear extension rail  52  are sized to provide 48 inches of cutting capacity to the right of the blade with the fence being used. 
         [0034]    Extension rails configured as described above are quickly attachable to and detachable from a table saw without having to manipulate knobs and/or levers. A user can also attach and detach the extension rails without having to be within reach of the joint between the main rails and the extension rails. 
         [0035]      FIGS. 11 and 12  show an alternative embodiment where an extension rail  110  includes two latch plates  112  and  114  attached to and extending out from the extension rail. Latch plates  112  and  114  are configured to extend into a hollow main rail  116  and hook behind a pin or bolt  118  extending across main rail  116 . 
         [0036]      FIG. 13  shows an alternative embodiment where a clamping mechanism holds an extension rail  120  to a main rail  122 . An anchor  124  is attached to main rail  122 , and the anchor includes a flange or head  126 . A clamp plate  128  is mounted in extension rail  120 , and the clamp plate includes cutouts, such as cutout  130 , configured to move over and fit around head  126  on anchor  124 . A lever  132  is linked to clamp plate  130  via a linkage  134  so that movement of the lever causes clamp plate  128  and cutout  130  to move over head  126  so that head  126  will catch on one or more edges of cutout  130 . Continued movement of the lever pulls or clamps extension rail  120  and main rail  122  together by cutout  130  catching on head  126 . Extension rail  120  includes a recess or cutout  136  to receive lever  132 . Guide pins can be used to align the rails, such as guide pin  138 . A clamping mechanism of this type can provide significant force to hold the rails together, for example, 1,000 pounds or more. 
       INDUSTRIAL APPLICABILITY 
       [0037]    The extension rails described herein are applicable to table saws and other power tools for woodworking, manufacturing, packaging, construction, carpentry, material processing, etc. 
         [0038]    It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and sub-combinations of the various elements, features, functions and/or properties disclosed herein. No single feature, function, element or property of the disclosed embodiments is essential to all of the disclosed inventions. Similarly, the recitation of “a” or “a first” element, or the equivalent thereof, should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. 
         [0039]    It is believed that the following claims particularly point out certain combinations and sub-combinations that are directed to disclosed inventions. Inventions embodied in other combinations and sub-combinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure.