Patent Publication Number: US-7581477-B2

Title: Saw table and clamping mechanism therefor

Description:
RELATED APPLICATION 
     This application is a Continuation of U.S. Non-Provisional patent application Ser. No. 10/961,869 filed Oct. 8, 2004, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/567,213 filed Apr. 30, 2004, both of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention relates to a saw table and, more specifically, a clamping mechanism for use on a saw table. 
     2. Description of the Prior Art 
     Saw tables are known in the building construction and remodeling industry. Typically, a saw is mounted on the saw table for cutting a work piece, such as vinyl siding, aluminum siding, tile, steel, half-wrapped log siding, textured ceiling tile, etc. Since cutting such materials by hand leads to inaccurate and unusable parts, which then must be scrapped, the saw tables have gained wide appeal in the above-mentioned industries. 
     The saw table typically includes a table base, which stabilizes the work piece and allows a user to precisely position the work piece with respect to the saw to perform desired cuts of various angles and orientations. A pair of tracks extend parallel to each other across the saw table, and a saw cradle is slidably supported by the tracks for rectilinear movement along the tracks. 
     For performing the desired cuts on saw tables of the prior art, the work piece is positioned on the table base at a desired angle in relation to the saw. The work piece is held in place, usually by hand, to perform the operation. Thus, significant care must be taken by operators to keep hands out of the path of the saw while preventing the work piece from deviating from the desired position. In response to this problem, several solutions have been developed in the prior art. 
     For example, it is known to provide a C-clamp on the table base described above for holding the work piece in place. Although the C-clamp is an inexpensive solution to the aforementioned problem of holding the work piece in place, multiple C-clamps are necessary are different points along a length of the work piece to prevent the work piece from rotating when contacted by the saw. In addition, installing the C-clamps to clamp the work piece against the table base is tedious, labor-intensive, time-consuming, and inefficient. 
     More elaborate clamping mechanisms have also been developed for clamping the work piece on the saw table. U.S. Pat. No. 5,103,704 discloses a saw table that includes an actuation bar having a first end and a second end operatively connected to clamping blocks. The clamping blocks are each disposed on a guide rod. A first pivoting screw is connected to the first end of the actuation bar, and a second pivoting screw is connected to the second end of the clamping bar. The screws are threaded through the respective clamping blocks for pivotal movement about a pivot axis. The pivotal movement of the screws clamps or releases the clamping blocks from the guide rods. Thus, the clamping bar may be pivoted in one direction to clamp the clamping blocks, and thus the work piece, and in the opposite direction to release the clamping blocks. However, such a clamping mechanism is complicated and requires numerous moving parts that function together to perform the clamping function. This increases the cost of the saw table, yet is still labor-intensive. Operation of the clamping mechanism by clamping and releasing the mechanism may also be tedious, labor intensive, time consuming, and inefficient. Furthermore, the clamping mechanism has set positions, and cannot compensate for work pieces of various thicknesses during operation without preadjustment for the specific work piece on the saw table. As a result, insufficient or excessive clamping force may be provided by the clamping mechanism absent further features that add even more complexity to the clamping mechanism. 
     Despite the efforts in the prior art to develop the aforementioned clamping mechanisms, there remains an opportunity to develop less complex clamping mechanisms that are less expensive, yet improve the speed and efficiency with which the work piece may be clamped to the table base without sacrificing the stability or clamping force with which the work piece is clamped to the table base. 
     SUMMARY OF THE INVENTION AND ADVANTAGES 
     The subject invention provides a saw table and a clamping mechanism for use on the saw table. The clamping mechanism includes a clamping bar having a first end and a second end. A longitudinal axis is defined between the first and second ends. A first pivoting arm is operatively connected to one of the ends of the clamping bar to support the clamping bar for rotation about a pivot axis. A biasing device biases the clamping bar about the pivot axis to clamp a work piece between the clamping bar and a table base. 
     The biasing device allows the clamping mechanism to accommodate work pieces of various thicknesses while providing a preset clamping force on the work piece, regardless of the thickness of the work piece. Furthermore, the biasing device provides all of the necessary force to maintain the work piece in position, and the work piece may by positioned with maximized efficiency by lifting the clamping bar and sliding the work piece beneath the clamping bar, and sliding the work piece out from beneath the clamping bar to remove the work piece from the saw table. 
    
    
     
       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 perspective view of a saw table including a clamping mechanism; 
         FIG. 2  is a an exploded view of the saw table of  FIG. 1 ; 
         FIG. 3  is a partially exploded view of a pivoting arm of the clamping mechanism of  FIG. 1 ; 
         FIG. 4  is a partial perspective view of the saw table of  FIG. 1  showing a saw cutting a work piece and a clamping bar clamping the work piece; 
         FIG. 5  is another partial perspective view of the saw table of  FIG. 1  showing the pivoting arm and the clamping bar relative to the work piece; and 
         FIG. 6  is another partial perspective view of the saw table of  FIG. 1  showing the saw cutting the work piece. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A saw table is shown generally at  10  in  FIG. 1 . The saw table  10  is used for positioning and cutting a work piece  12  (shown in phantom lines in FIGS.  1  and  3 - 6 ), which may include vinyl siding, aluminum siding, tile, steel, half-wrapped log siding, textured ceiling tile, etc. The saw table  10  includes a table base  14  having a first base end  16  and a second base end  18 . The table base  14 , to be described in further detail below, stabilizes the work piece  12  and allows a user to precisely position the work piece  12  to perform desired cuts of various angles and orientations. 
     As shown in  FIGS. 4-6 , a saw  20  or circular saw  20  may be used to perform the cutting operation. It should be noted that other types of saws  20  may be used to work on different types of materials. Additionally, the saw  20  may be outfitted with different types of blades, e.g., a masonry blade, to cut different types of materials. 
     The saw table  10 , as shown in the Figures, is lightweight and portable, i.e., it may be moved from jobsite to jobsite with ease. The saw table  10  may be supported by a pair of sawhorses (not shown) or other work table supports or may be placed on the ground. Thus, breakdown is fast and very time efficient. 
     The saw table  10  includes a clamping mechanism  22  for clamping the work piece  12  and preventing the work piece  12  from moving to make cutting of the work piece  12  more accurate, safe, and efficient, as compared to saw tables without the clamping mechanism  22 . The clamping mechanism  22  includes a clamping bar  24  that has a first end  26  and a second end  28 . A longitudinal axis L is defined between the first  26  and second  28  ends. The clamping bar  24  extends across the table base  14  between the first  26  and second  18  base ends to clamp the work piece  12  regardless of position of the work piece  12  between the first  26  and second  18  base ends. Furthermore, by extending across the table base  14 , the clamping bar  24  may sufficiently contact the work piece  12  to prevent the work piece  12  from rotating without the need for additional clamping mechanisms  22 . 
     The clamping bar  24  has a cylindrical shape, since clamping bars having sharp edges may damage the work piece  12 . In addition, a sleeve  30  is disposed about the clamping bar  24  for frictionally engaging the work piece  12  and for further preventing damage to the work piece  12  as a result of contact with the clamping bar  24 . The sleeve  30  is formed from a polymer such as rubber; however, other materials that will accomplish the above-stated purposes of frictionally engaging the work piece  12  and preventing damage to the work piece  12  may also be suitable for the sleeve  30 . 
     The clamping mechanism  22  further includes a first pivoting arm  32  and, preferably, a second pivoting arm  34  that mirrors the first pivoting arm  32 . The first pivoting arm  32  is operatively connected to the first end  26  of the clamping bar  24 , and the second pivoting arm  34  is operatively connected to the second end  28  of the clamping bar  24 . The operative connection is discussed in further detail below. The pivoting arms  32 ,  34  pivotally support the clamping bar  24  at the first  26  and second  18  base ends, respectively, of the table base  14  for pivotal movement about a pivot axis A that is parallel to the longitudinal axis L. 
     Referring to  FIGS. 1 and 2 , each of the arms  32 ,  34  includes a socket  40  for receiving the respective first  26  and second  28  ends of the clamping bar  24  to operatively connect the clamping bar  24  to the pivoting arms  32 ,  34 . As best shown in  FIG. 3 , the socket  40  is cylindrical in shape, which allows the clamping bar  24  to rotate within the socket  40 . As a result, during use of the clamping mechanism  22  to clamp the work piece  12 , the work piece  12  may be slid out from under the clamping bar  24 , with such sliding aided by the rotation of the clamping bar  24 . By rotating during the sliding of the work piece  12 , scuffing or other damage to the work piece  12  due to contact with the clamping bar  24  is also avoided. 
     Referring to  FIG. 3 , each socket  40  includes an end wall  42  extending transverse to the longitudinal axis L for abutting and restricting movement of the ends  26 ,  28  of the clamping bar  24  along the longitudinal axis L. The end walls  42  of the respective sockets  40  sandwich the clamping bar  24 , which prevents the clamping bar  24  from falling out of or sliding through the sockets  40 . In other embodiments, a ledge, tab, etc. (none of which are shown) may be used instead of the end walls  42  to prevent the clamping bar  24  from moving along the longitudinal axis L. 
     As shown in  FIG. 3 , each of the pivoting arms  32 ,  34  further includes a lever wall  46  that extends transversely to the longitudinal axis L from the socket  40  to the pivot axis A. The pivoting arms  32 ,  34  are connected to the table base  14  through the lever wall  46 , which is described below in further detail. Each of the pivoting arms  32 ,  34  further includes a peripheral housing wall  48  that extends parallel to the longitudinal axis L and transversely from the socket  40  and the lever wall  46 . The housing wall  48  encloses the lever wall  46  and extends beyond the lever wall  46  to define an opening  50  between the lever wall  46  and the housing wall  48 . Each of the arms  32 ,  34  further includes a support wall  52  that extends across the lever wall  46  between the socket  40  and the housing wall  48  to reinforce the pivoting arms  32 ,  34  and to prevent the socket  40  from breaking away from the housing wall  48  during operation of the clamping mechanism  22 . A cover  54  extends parallel to the lever wall  46  on each of the pivoting arms  32 ,  34  and closes the housing wall  48  for preventing debris or other foreign objects from entering inside the housing wall  48 . 
     A spring  56  biases the clamping bar  24  about the pivot axis A toward the table base  14  to clamp the work piece  12  between the clamping bar  24  and the table base  14 . Other biasing devices may also be suitable, such as a flexible arm, piston, etc. (none of which are shown). The spring  56  is disposed about a center axis C, and provides a biasing force along the center axis C. Alternatively, it is to be appreciated that the spring  56  may provide the biasing force transverse to the center axis C. Preferably, each pivoting arm  32 ,  34  includes the spring  56 ; however, the spring  56  is necessary in only one of the pivoting arms  32 ,  34  to provide the biasing force to the clamping bar  24 . 
     One end of each spring  56  is connected to the respective pivoting arm  32 ,  34 . More specifically, each lever wall  46  defines a first hole  60 , and one end of the spring  56  extends through the hole  60  for connecting the end of the spring  56  to the lever wall  46 . In other embodiments, the spring  56  may be connected to the pivoting arm  32 ,  34  through an alternative connection, such as by wrapping around a post  44  or tab (neither of which connections are shown). 
     The spring  56  extends in tension through each of the openings  50  defined by the housing wall  48  and the lever wall  46  of the pivoting arm  32 ,  34 , between the lever wall  46  on the one end and an adjacent track support  36 ,  38 , which will be described in further detail below, on the other end. The spring  56  is connected to the track support  36 ,  38  by a screw, bolt, or other fastener. Thus, the springs  56  are pulled or retracted as the pivoting arms  32 ,  34  move. 
     The spring  56  resists pivotal movement of the clamping bar  24  in the opposite direction of the table base  14  about the pivot axis A. As a result, the clamping bar  24 , in a starting position, is in contact with the table base  14 , and any movement of the clamping bar  24  away from the table base  14  is met with resistance from the spring  56 . It is to be appreciated that when the sleeve  30  is present, the sleeve  30  is in contact with the table base  14  in the starting position. Thus, in operation, the clamping bar  24  may be lifted to slide the work piece  12  under the clamping bar  24  and into a desired position for cutting, which is shown in  FIGS. 4 and 5 . The clamping bar  24  may then be released to clamp the work piece  12  to the table base  14  in preparation for cutting the work piece  12 , which is shown in  FIG. 6 . 
     The clamping mechanism  22  enables work pieces  12  of various thicknesses to be clamped between the clamping bar  24  and the table base  14 . More specifically, the clamping mechanism  22  provides a sufficient clamping force to clamp relatively thin work pieces  12  between the clamping bar  24  and the table base  14  to prevent rotation of the work piece  12  when contacted by the saw  20 . For work pieces  12  of relatively greater thicknesses, the clamping mechanism  22  provides an insufficient biasing force to damage or deform the work piece  12 . Thus, the clamping mechanism  22  is self-adjusting to the thickness of the work piece  12  to be clamped. 
     As discussed in further detail below, the saw  20  is allowed to travel between a first position and a second position along the saw table  10 . The work piece  12  may be positioned relative to the saw  20  such that the desired cut may be performed. During cutting, the work piece  12  does not move relative to the saw table  10 ; only the saw  20  moves. This, in addition to the clamping mechanism  22 , makes cutting more accurate and safe. 
     Referring to  FIGS. 1 and 2 , the table base  14  includes a work surface  64 , such as treated plywood, for supporting the work piece  12 . However, those skilled in the art will recognize that the work surface  64  may be made from a variety of suitable materials. The work surface  64  may define an oblong slot  66 , which functions as a handle for allowing a user to carry the saw table  10 . A pre-cut groove  98  may be pre-formed in the work surface  64  to prevent the saw  20  blade from cutting through and damaging the work surface  64  during operation of the saw  20 . 
     As best shown in  FIGS. 1 and 2 , the table base  14  may also include a metal frame  68  that includes a series of beams  70  that are formed from aluminum. The frame  68  may be disposed adjacent a periphery of the table base  14  for reinforcing the work surface  64 , with additional beams  70  disposed beneath the table base  14  for providing additional support. 
     In addition to the clamping mechanism  22  and the table base  14 , the saw table  10  further includes a first track  72  and, preferably, a second track  74  both supported by the table base  14  and extending parallel to the longitudinal axis L between the first  26  and second  18  base ends and spaced from the table base  14 . Due to the rigid nature of the frame  68  that supports the work surface  64 , the tracks  72 ,  74  are supported by the frame  68  of the table base  14 . A saw cradle  76  is slidably mounted on the first  72  and second  74  tracks for movement between the first position and the second position, as set forth above, and for supporting the saw  20 . The first  72  and second  74  tracks are fixed with respect to the table base  14 , in which case the saw cradle  76  travels a fixed linear path between the first and second positions. 
     The tracks  72 ,  74  define opposing grooves  78  that receive opposite sides of the saw cradle  76  and prevent the saw cradle  76  from separating from the tracks  72 ,  74 . The first  72  and second  74  tracks further include an insert  80  disposed in each groove for protecting the grooves  78  from wear. The insert  80  is preferably made of plastic, but may be made of other materials. 
     A first track support  36  and a second track support  38  are mounted to the first  26  and second  18  base ends, respectively. The track supports  36 ,  38  mount the first  72  and second  74  tracks on the table base  14  at the respective first  26  and second  18  base ends, and space the tracks  72 ,  74  from the table base  14  to allow the work piece  12  to be slid beneath the tracks  72 ,  74 . More specifically, the track supports  36 ,  38  are mounted to the frame  68  of the table base  14  at the respective base ends  16 ,  18 . Thus, the work piece  12  may be positioned in the path of the saw cradle  76  such that as the saw cradle  76  is slid along the tracks  72 ,  74 , the saw  20  cuts the work piece  12  at the desired angle. Optionally, a mid-track support  36 ,  38  may also be mounted to the table base  14  to reinforce the tracks  72 ,  74  and to prevent the tracks  72 ,  74  from bending as the saw cradle  76  moves along the tracks  72 ,  74 . The mid-track support  36 ,  38 , when present, defines a notch  82  adjacent to the clamping bar  24  for preventing the mid-track support  36 ,  38  from impeding the movement of the clamping bar  24 . 
     As previously stated, the pivoting arms  32 ,  34  pivotally support the clamping bar  24  at the first  26  and second  18  base ends, respectively, of the table base  14 . More specifically, the pivoting arms  32 ,  34  are mounted on the respective track supports  36 ,  38 , opposite the tracks  72 ,  74 . However, it is to be appreciated that other mounting arrangements are also possible for the pivoting arms  32 ,  34 , such as mounting the pivoting arms  32 ,  34  directly to the table base  14  or to the tracks  72 ,  74 . A bushing  84  is mounted on and extends outwardly from each of the track supports  36 ,  38  for pivotally mounting the pivoting arms  32 ,  34  on the respective track supports  36 ,  38 . Each of the lever walls  46  further defines a second hole  62  for receiving the bushing  84 . However, the bushing  84  may support the pivoting arm  32 ,  34  through other mechanisms  22 ,  86 , such as through a fitting, supplemental bracket, etc. (none of which are shown). 
     To further aid in the positioning and cutting of the work piece  12 , a pivot foot  88  may be rotatably coupled to the table base  14 , more specifically, the work surface  64  of the table base  14 . The pivot foot  88  includes a work piece  12  abutment edge  90  that defines an acute angle with the longitudinal axis L for accepting an edge of the work piece  12  to align the work piece  12  at the desired angle for cutting. A coupling mechanism  86  is provided for selectively preventing rotation of the pivot foot  88 . More specifically, the pivot foot  88  defines an aperture  92  and the coupling mechanism  86  includes a post  44  that passes through the aperture  92  and into the work surface  64  of the table base  14 . A nut  94  is embedded in the work surface  64  of the table base  14 , and the post  44  includes a threaded portion  96  for engaging the nut  94 . Thus, the pivot foot  88  may be allowed to rotate by unscrewing the post  44 , and secured in place by screwing the post  44  into the nut  94 . 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.