Abstract:
A splitting knife adjustment structure used in a table saw for adjusting alignment of a splitting knife with the cutting direction of the saw blade of the table saw is disclosed to include a mounting plate member, an adjustment member supported on the mounting plate member to hold a splitting knife and movable relative to the mounting plate member along an arched path.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation-in-part of U.S. application Ser. No. 11/754,469 entitled SPLITTING KNIFE ADJUSTMENT STRUCTURE FOR TABLE SAW filed on May 29, 2007, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to table saws and more specifically, to a splitting knife adjustment structure used in a table saw for adjusting alignment of a splitting knife with the cutting direction of the saw blade of the table saw. 
         [0004]    2. Description of the Related Art 
         [0005]      FIG. 1  shows a conventional table saw  1 , which comprises a base  2 , a connecting device  3 , a saw blade  4 , and a splitting knife  5 . The connecting device  3  carries the splitting knife  5  to move with the saw blade  4  up and down synchronously. The splitting knife  5  is used to prevent accidental jamming of the cut parts of the workpiece (for example, wooden material) during cutting action of the saw blade  4 . 
         [0006]    The splitting knife  5  is adapted to provide a safety effect. To achieve this safety effect, the splitting knife  5  must be placed on the extension line L 1  of the cutting direction of the saw blade  4 , as shown in  FIGS. 1 and 2 , so that the workpiece can be positively cut without interference by the splitting knife  5 . However, in most conditions, the splitting knife  5  may be deviated from the extension line L 1  of the cutting direction of the saw blade  4  due to a matching precision problem between the splitting knife  5  and the connecting device  3 , or the splitting knife  5  may be hit accidentally by an external force to bias from the extension line L 1  of the cutting direction of the saw blade  4 . In this case, the cut parts of the workpiece may interfere with the splitting knife  5 , endangering workers&#39; safety. Therefore, it is quite important to keep the extending direction of the splitting knife  5  in conformity with the cutting direction of the saw blade  4 . 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention has been accomplished under the circumstances in view. It is the main objective of the present invention to provide a splitting knife adjustment structure for table saw, which allows quick alignment of the splitting knife with the saw blade, assuring smooth and safe cutting operation. 
         [0008]    To achieve this objective of the present invention, the splitting knife adjustment structure for a table saw comprises a mounting plate member having an end portion and an arched first surface at the end portion, an adjustment member movably coupled to the end portion of the mounting plate member and having an end portion provided with an arched bearing surface in contact with the arched first surface of the end portion of the mounting plate member, a fixation mechanism adapted to keep the arched first surface of the end portion of the mounting plate member in contact with the arched bearing surface of the end portion of the adjustment member, and a splitting knife fastened to the adjustment member. 
         [0009]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0011]      FIG. 1  illustrates a conventional saw blade and splitting knife linking structure in a table saw according to the prior art; 
           [0012]      FIG. 2  is a top view of  FIG. 1 , showing that the splitting knife is offset from the cutting direction of the saw blade; 
           [0013]      FIG. 3  is a top view of a splitting knife adjustment structure in a table saw in accordance with a first preferred embodiment of the present invention; 
           [0014]      FIG. 4  is an exploded view of the splitting knife adjustment structure in accordance with the first preferred embodiment of the present invention; 
           [0015]      FIG. 5  is a schematic drawing of the first preferred embodiment of the present invention, showing that the splitting knife is not in alignment with the cutting direction of the saw blade and is offset outwards; 
           [0016]      FIG. 6  is a schematic drawing of a part of the first preferred embodiment of the present invention, showing the position of the adjustment member before action; 
           [0017]      FIG. 7  corresponds to  FIG. 6 , showing the adjustment member moved horizontally inwards relative to the mounting plate member; 
           [0018]      FIG. 8  corresponds to  FIG. 6 , showing the adjustment member moved horizontally outwards relative to the mounting plate member; 
           [0019]      FIG. 9  is a schematic drawing of the first preferred embodiment of the present invention, showing that the splitting knife is offset outwards from the cutting direction of the saw blade at an angle; 
           [0020]      FIG. 10  is a schematic drawing of a part of the first preferred embodiment of the present invention, showing the position of the adjustment member before action; 
           [0021]      FIG. 11  corresponds to  FIG. 10 , showing the adjustment member turned inwards relative to the mounting plate member; 
           [0022]      FIG. 12  corresponds to  FIG. 10 , showing the adjustment member turned outwards relative to the mounting plate member; 
           [0023]      FIG. 13  is a plane view of a part of the first preferred embodiment of the present invention, showing the locating pin fastened to the splitting knife and the connection plate; 
           [0024]      FIG. 14  corresponds to  FIG. 13 , showing the locating pin disengaged from the splitting knife and the connection plate; 
           [0025]      FIG. 15  is a schematic drawing of the first preferred embodiment of the present invention, showing that the top of the splitting knife is higher in elevation than the saw blade; 
           [0026]      FIG. 16  is a schematic drawing of the first preferred embodiment of the present invention, showing that the top of the splitting knife is located at a same elevation with the saw blade; 
           [0027]      FIG. 17  is an exploded view of a part of the first preferred embodiment of the present invention, showing an alternate form of the end panel and the adapter plate; 
           [0028]      FIG. 18  is an exploded view of a part of a splitting knife adjustment structure in accordance with a second preferred embodiment of the present invention; and 
           [0029]      FIG. 19  corresponds to  FIG. 18  showing an alternate form of the end panel and the adapter plate. 
           [0030]      FIG. 20  is a schematic side view showing a splitting knife adjustment structure in accordance with a third embodiment of the present invention. 
           [0031]      FIG. 21  is a schematic of the splitting knife adjustment structure in accordance with the third embodiment of the present invention, showing the adjustment member biased outwards. 
           [0032]      FIG. 22  corresponds to  FIG. 20 , showing the adapter plate formed integral with the end panel in a single piece. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    Referring to  FIGS. 3-16 , a splitting knife adjustment structure  10  in accordance with a first preferred embodiment of the present invention is shown comprising a mounting plate member  12 , an adjustment member  15 , a splitting knife  19 , a fixation member  20 , two fastening rods  21 , a locating plate  22 , a locating pin  23 , a retainer ring  24 , a spring  25 , and two guide members  26 . 
         [0034]    As shown in  FIGS. 3 and 4 , the mounting plate member  12  has a side panel  13  coupled to the motor output shaft  101  of the table saw  100  and kept in parallel to the saw blade  102 , and an end portion formed of an end panel  14  extending from one end of the side panel  13 . The end panel  14  has an arched concave surface  141 , an arched convex surface  142  opposite to the concave surface  141 , and two elongated slots  143  cut through the concave surface  141  and the convex surface  142 . 
         [0035]    The adjustment member  15  has a connection plate  16 , a bearing plate  17 , and an end portion formed by an adapter plate  18 . Bending a metal plate into shape forms the connection plate  16  and the bearing plate  17 . The connection plate  16  is arranged in parallel to the side panel  13  of the mounting plate member  12 , having a positioning hole  161  and two guide holes  162 . The bearing plate  17  has two elongated through holes  171 , and a flat surface  172  facing the concave surface  141  of the end panel  14  of the mounting plate member  12 . The adapter plate  18  is set between the end panel  14  of the mounting plate member  12  and the bearing plate  17 , having an arched convex surface  182 , a flat bearing surface  183  opposite to the convex surface  182 , and two elongated through holes  181  cut through the convex surface  182  and the flat bearing surface  183 . The convex surface  182  of the adapter plate  18  fits the concave surface  141  of the end panel  14  of the mounting plate member  12 . The flat bearing surface  183  of the adapter plate  18  is stopped against the flat surface  172  of the bearing plate  17 . 
         [0036]    The splitting knife  19  is connected to the connection plate  16  of the adjustment member  15  (this will be described further), having two locating holes  191  and a sliding slot  192 . 
         [0037]    According to this embodiment, the fixation member  20  and the two fastening rods  21  constitute a fixation mechanism to keep the arched concave surface  141  of the mounting plate member  12  in contact with the convex surface  182  of the adapter plate  18 ; wherein: 
         [0038]    The fixation member  20  has a plate body  20   a . The plate body  20   a  has an arched concave surface  202 , and two screw holes  201 . The concave surface  202  of the plate body  20   a  fits the convex surface  142  of the end panel  14  of the mounting plate member  12  so that the fixation member  20  is movable along the arched surface of the convex surface  142  of the end panel  14  of the mounting plate member  12 . 
         [0039]    The fastening rods  21 , which are embodied as screw rods in this preferred embodiment, each have a threaded shank  211  and a head  212  at one end of the threaded shank  211 . The threaded shanks  211  of the fastening rods  21  are respectively inserted in proper order through the elongated through holes  171  of the bearing plate  17 , the elongated through holes  181  of the adapter plate  18  and the elongated slots  143  of the end panel  14  of the mounting plate member  12  and then respectively threaded into the screw holes  201  of the fixation plate  20 , keeping the heads  212  of the fastening rods  21  stopped against the bearing plate  17 . Thus, the adjustment member  15  is firmly secured to the mounting plate member  12  to hold the splitting knife  19  in line with the cutting direction of the saw blade  102 , as shown in  FIG. 3 . 
         [0040]    Referring to  FIGS. 4 ,  13  and  14 , the locating plate  22  has an outer surface  221 , an opening  222 , two through holes  223 , two uprights  224  respectively perpendicularly extending from the outer surface  221 , and a top plate  225  integrally connected between the uprights  224  and spaced from the surface  221  at a distance. The top plate  225  has a hole  225   a  in alignment with the opening  222 . 
         [0041]    The locating pin  23  has one end inserted through the hole  225   a  of the top plate  225 , the opening  222  of the locating plate  22 , one locating hole  191  of the splitting knife  19  and the positioning hole  161  of the connection plate  16 , and the other end, namely, the head  231  stopped at the top plate  225 . The locating pin  23  further has a locating groove  232  extending around the periphery between its two distal ends. 
         [0042]    The retainer ring  24  is a C-shaped retainer fastened to the locating groove  232  of the locating pin  23  and positioned between the top plate  225  and the outer surface  221  of the locating plate  22 . 
         [0043]    The spring  25  is sleeved onto the locating pin  23  and stopped between the retainer ring  24  and the top plate  225  to impart a biasing force to the locating pin  23 , holding the locating pin  23  in the locating hole  191  of the splitting knife  19  and the positioning hole  161  of the connection plate  16 . 
         [0044]    The two guide members  26  are respectively inserted through the through holes  223  of the locating plate  22  and the sliding slot  192  of the splitting knife  19  and the guide holes  162  of the connection plate  16  and respectively screwed up with a respective nut  103 . 
         [0045]    After understanding of the assembly and relative positioning of the component parts of the splitting knife adjustment structure  10 , the adjustment procedure of the present invention to adjust horizontal displacement and rotation of the splitting knife  19  relative to the saw blade  102  and the adjustment procedure to adjust vertical displacement of the splitting knife  19  relative to the saw blade  102  are described hereinafter. 
         [0046]    In case the splitting knife  19  is forced by an external factor (for example, impact) to displace outward relative to the saw blade  102  (see  FIG. 5 ) and becomes unable to split the cut parts of the workpiece, an adjustment is necessary. In this case, we can loose the fastening rods  21  and move the adjustment member  15  toward the mounting plate member  12  (see  FIGS. 6 and 7 ) to set the splitting knife  19  into alignment with the cutting direction of the saw blade  102  again, and then fasten tight the fastening rods  21  to fix the splitting knife  19  in position. In case the splitting knife  19  is displaced inward relative to the saw blade  102  and becomes unable to split the cut parts of the workpiece, we can loose the fastening rods  21  and move the adjustment member  15  in direction apart from the mounting plate member  12  (see  FIGS. 6 and 8 ) to set the splitting knife  19  into alignment with the cutting direction of the saw blade  102  again, and then fasten tight the fastening rods  21  to fix the splitting knife  19  in position. 
         [0047]    In case the splitting knife  19  is biased horizontally at an angle toward the outer side relative to the saw blade  102  as shown in  FIG. 9 , an adjustment is necessary. In this case, we can loose the fastening rods  21  slightly and then turn the adjustment member  15  inwards from the position shown in  FIG. 10  to the position shown in  FIG. 11 . At this time, the bearing plate  17  forces the adapter plate  18  to move along the concave surface  141  of the end panel  14  of the mounting plate member  12  in direction apart from the side panel  13 , causing the splitting knife  19  to be turned horizontally into alignment with the cutting direction of the saw blade  102 , and at the same time the fixation plate  20  is moved along the convex surface  142  of the end panel  14  in direction away from the side panel  13 . After fastening up the fixation plate  20  and the fastening rods  21 , the adjustment member  15  and the splitting knife  19  are locked in the adjusted position. In case the splitting knife  19  is biased horizontally at an angle toward the inner side relative to the saw blade  102 , we can loose the fastening rods  21  slightly and then turn the adjustment member  15  outwards. At this time, the bearing plate  17  forces the adapter plate  18  to move along the concave surface  141  of the end panel  14  of the mounting plate member  12  in direction toward the side panel  13 , and at the same time the fixation plate  20  is moved along the convex surface  142  of the end panel  14  in direction toward the side panel  13 , causing the splitting knife  19  to be turned horizontally into alignment with the cutting direction of the saw blade  102 . After fastening up the fixation plate  20  and the fastening rods  21 , the adjustment member  15  and the splitting knife  19  are locked in the adjusted position. 
         [0048]    With respect to adjustment of vertical displacement of the splitting knife  19  relative to the saw blade  102 , please refer to  FIGS. 13 ,  15  and  16 .  FIG. 15  shows the bottom end of the sliding slot  192  of the splitting knife  19  stopped at one guide member  26 , and the locating pin  23  is kept, subject to the spring force of the spring  25 , engaged into the lower locating hole  191  of the splitting knife  19  and the positioning hole  161  of the connection plate  16  (see  FIG. 13 ) to lock the splitting knife  19  in the position above the elevation of the saw blade  102 , as shown in  FIG. 15 . When wishing the adjust the position of the splitting knife  19  from the position shown in  FIG. 15  to the position below the elevation of the saw blade  102  as shown in  FIG. 16 , pull the head  231  of the locating pin  23  outwards against the spring force of the spring  25  to disengage the locating pin  23  from the positioning hole  161  of the connection plate  16  and the lower locating hole  191  of the splitting knife  19 , and then pull the splitting knife  19  downwards to have the top end of the sliding slot  192  be stopped at the other guide member  26 , and then release the head  231  of the locating pin  23  from the hand for enabling the compressed spring  25  to return to its former shape and to push the locating pin  23  into the upper locating hole  191  of the splitting knife  19  and the positioning hole  161  of the connection plate  16 , thereby locking the splitting knife  19  in the adjusted position. 
         [0049]    By means of the arched junction between the end panel  14  and the adapter  18 , the splitting knife adjustment structure  10  allows rotating adjustment of the position of the splitting knife  19  horizontally; by means of the flat junction between the adapter plate  18  and the bearing plate  17 , the splitting knife adjustment structure  10  allows adjustment of horizontal displacement of the position of the splitting knife  19 ; by means of the arrangement of the locating plate  22  and the locating pin  23 , the splitting knife adjustment structure  10  allows adjustment of vertical displacement of the position of the splitting knife  19 . Therefore, when the splitting knife  19  is biased or deviated from alignment with the cutting direction of the saw blade  102  due to inaccurate matching of the component parts or an accidental impact, the user can adjust the splitting knife  102  into accurate alignment with the cutting direction of the saw blade  102  conveniently, assuring smooth and safe cutting operation. 
         [0050]    In the aforesaid first embodiment, the concave surface  141  of the end panel  14  of the mounting plate member  12  matches the convex surface  182  of the adapter plate  18  to guide movement of the adapter plate  18  along a smoothly curved track. Alternatively, as shown in  FIG. 17 , the end panel  14 ′ can be made having a convex surface  141 ′ to match the concave surface  182 ′ of the adapter plate  18 . 
         [0051]      FIG. 18  shows a splitting knife adjustment structure  30  in accordance with a second preferred embodiment of the present invention. Similar to the aforesaid first embodiment, the splitting knife adjustment structure  30  of this second embodiment comprises a mounting plate member  31 , an adjustment member  33 , two fastening rods  36 , and a fixation member  37 . Similarly, the mounting plate member  31  has an end panel  32 , which has an inner concave surface  321  and two elongated slots  322 . The adjustment member  33  is integrally formed with a connection plate  34  and an adapter plate  35 . Bending a metal plate into shape forms the connection plate  34  and an adapter plate  35 . The adapter plate  35  according to this embodiment is an integrated member of the adapter plate  18  and bearing plate  17  of the aforesaid first embodiment. Further, the adapter plate  35  has two through holes  351 , and a bearing surface  352 . The bearing surface  352  is a convex surface fitting the concave surface  321  of the end panel  32 . By means of the smoothly arched junction between the end panel  32  and the adapter plate  35 , the splitting knife adjustment structure  30  allows rotating adjustment of the position of the splitting knife. 
         [0052]    Referring to  FIG. 19 , the end panel  32 ′ can be made having a convex surface  321 ′ to match the concave surface  352 ′ of the adapter plate  35 ′. By means of the smoothly arched junction between the end panel  32 ′ and the adapter plate  35 ′, rotating adjustment of the position of the splitting knife is allowed. 
         [0053]    The fixation member  20  in the aforesaid various embodiments may be omitted.  FIGS. 20 and 21  show a splitting knife adjustment structure  40  in accordance with a third preferred embodiment of the present invention. According to this third preferred embodiment, the splitting knife adjustment structure  40  comprises a mounting plate member  41 , an adjustment member  44 , and a fixation mechanism, which is formed of two fastening rods  49 , and two soft cushions  50 . 
         [0054]    The mounting plate member  41  has an end panel  42 , and an adapter plate  43  set between the end panel  42  and the adjustment member  44 . The end panel  42  has two screw holes  421 . The adapter plate  43  forms an end portion of the mounting plate member  41 , having an arched convex surface  431 . 
         [0055]    The adjustment member  44  is an angled plate member, having a connection plate  45  and a bearing plate  46 . The connection plate  45  is for the fixation of the splitting knife  19 . The bearing plate  46  forms an end portion of the adjustment member  44 , having an arched concave surface  47  and two through holes  48 . 
         [0056]    Based on the aforesaid structure, a user can bias the adjustment member  44  outwards to move the splitting knife  19  toward the inside (see  FIG. 20 ), or bias the adjustment member  44  inwards to move the splitting knife  19  toward the outside (see  FIG. 21 ), and then insert the fastening rods  49  through the through holes  48  of the bearing plate  46  and the adapter plate  43 , and fastened the fastening rods  49  to the screw holes  421  of the mounting plate member  41  to affix the splitting knife  19  in position. The arrangement of the cushions  50  (between the heads of the fastening rods  49  and the bearing plate  46  of the adjustment member  44 ) enhances the fixation tightness. The end panel  42  and the adapter plate  43  may be integrally made in a single piece, achieving the same effect. As shown in  FIG. 22 , the mounting plate member  41 ′ has the end panel and the adapter plate formed in integrity. 
         [0057]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.