Abstract:
The present invention relates to pair of saw blades, comprising a first saw blade and a second saw blade which are coaxial and rotating in opposite directions, wherein each saw blade comprises a circular blade body and saw teeth at periphery of the blade body, a gap is arranged between the first saw blade and the second saw blade, the first blade body of the first saw blade is provided with a protrusion protruding toward the second saw blade, and the second blade body of the second saw blade is provided with a groove corresponding to the protrusion. Therefore, it is difficult to cause interference between the two saw blades even though either of the saw blades is deformed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims priority to and the benefit of Chinese Patent Application No. 201220438033.0, filed on Aug. 30, 2012, the disclosure of which is incorporated herein in its entirety by reference. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a machining tool, and more specifically, relates to pair of saw blades. 
       BACKGROUND TECHNOLOGIES 
       [0003]    Compared to a cutting tool with a single saw blade, a cutting tool featuring counter-rotating blades is advantaged in high operating efficiency, by reducing kickback force, park output and vibrations, making it easier to make precision and smooth cuts, and is therefore widely applied. However, in order to enable such a set of Dual Saw Blade to work, it is necessary to leave a proper gap between the two saw blades, so that the heat dissipated while these two saw blades are working and the material powder produced when cutting materials can be discharged from the space. 
         [0004]    Chinese Patent Application No. 201020262693 discloses a saw blade adapted for a cutting machine with double saw blades, the saw blade is supposed to solve the problem with the existing double saw blades such as easy transformation and increasing the gap between the blades after certain cutting period, which makes the paired Saw Blade to fail. In this patent, an annular convex rib (the 1 st  rib) is arranged near the tooth root at one side of the blade body, and an annular convex rib (the 2 nd  rib) is arranged at the edge of the arbor at one side of the blade body, and the 1 st  rib and the 2 nd  rib are homocentric with the arbor of the saw blade. Therefore, there is no space between the core part of the inner saw blade and the outer saw blade, which will not result in a radial deformation caused by the axial displacement of the core part of the saw blade. However, a total of two kinds of convex ribs are arranged in the patent, therefore the convex rib dose to the core part of the saw blade is prone to be contaminated by material powder produced during cutting, which is difficult to be cleaned off. 
         [0005]    Chinese Patent Application No. 02812228.3 discloses a kind of paired saw blades, in this patent, a spacer is arranged in the space between two saw blades rotating in opposite directions, and the spacer is connected to the blade body of one saw blade, so that the spacer can support the saw blade and slide along the periphery of the opposite rotating saw blade during cutting. However, the spacer disclosed in this patent application is connected to the saw blade by such means as adhesion; when the saw blade is operating at high speed, heat is generated at the surface of the saw blade, which often causes the spacer to fall off. 
       SUMMARY 
       [0006]    The present invention provides pair of saw blades, which is advantaged in terms of long service life. 
         [0007]    In one aspect, the present invention provides pair of saw blades, comprising a first saw blade and a second saw blade which are coaxial and rotating in opposite directions, wherein each saw blade comprises a circular blade body and saw teeth at periphery of the blade body, a gap is arranged between the first saw blade and the second saw blade, the first blade body of the first saw blade is provided with a protrusion protruding toward the second saw blade, and the second blade body of the second saw blade is provided with a notch corresponding related to the protrusion from the first saw blade. 
         [0008]    The protrusion is located at any one or more positions between ¼ of the diameter of the first blade body and the end of the saw teeth, and the second blade body is provided with any one or more notches corresponding to the protrusion(s). 
         [0009]    The protrusion is an annular convex rib which is coaxial with the first blade body. 
         [0010]    The protrusion is a plurality of bumps distributed at the same or different intervals and forms a ring coaxial with the first blade body. 
         [0011]    The protrusion is aligned by at least two convex strips arranged equidistantly and a ring formed by the convex strips is coaxial with the first blade body; alternatively, the protrusion is a convex strip larger than a semicircle and a ring formed by the convex strips is coaxial with first blade body. 
         [0012]    Each of the convex strips is in the same shape and of the same size. 
         [0013]    The notch is annular and the annular notch is coaxial with the second blade body. 
         [0014]    The height of the protrusion related to the first blade body is greater than the depth of the notch of the second blade body. 
         [0015]    The width of the notch is greater than that of the protrusion. 
         [0016]    Either the first saw blade or the second saw blade is formed integrally. 
         [0017]    The benefits of the present invention are shown as follows: the present invention provides pair of saw blades, different from that in the prior art, and a gap is provided between two saw blades arranged side-by-side, which facilitates to dissipate the heat produced while the saw blades are working, and also facilitates to dean the material powder of the cut materials. In addition, in the present invention, a protrusion protruding toward the second blade body is also aligned at the blade body of one saw blade, and a notch corresponding to the protrusion is arranged at the blade body of the other saw blade. The width of the notch is greater than that of the protrusion, and therefore no interference between the two saw blades will be caused even if one of the saw blades is deformed. Moreover, since the notch of the present invention is an annular notch concentric with the second blade body, if the cutting powder comes into the saw blades when working, the cutting powder can be thrown out as long as the saw blades rotate at high speed so that self-cleaning effect can be achieved. 
         [0018]    Furthermore, the protrusion and the notch form an orbital rotation operation mode of, which avoids separation of the two saw blades while working or poor coordination between two groups of saw teeth. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a schematic diagram of pair of saw blades assembled according to the present invention; 
           [0020]      FIG. 2  is a schematic diagram showing the longitudinal section when a first saw blade is matched with a second saw blade; 
           [0021]      FIG. 3  is a schematic diagram showing the side of the first saw blade toward the second saw blade according to Example 1 of the present invention; 
           [0022]      FIG. 4  is a schematic diagram showing the side of the second saw blade toward the first saw blade according to Example 1 of the present invention; 
           [0023]      FIG. 5  is a schematic diagram showing the side of the first saw blade toward the second saw blade according to Example 2 of the present invention; 
           [0024]      FIG. 6  is a schematic diagram showing the side of the first saw blade toward the second saw blade according to Example 3 of the present invention. 
       
    
    
       [0025]    As shown in the drawings, in order to specify the structure of the examples for implementing the present invention. Specific structures and devices are marked in the drawings. However, this is merely for schematic illustration, but not intended to limit the present invention to the specific structures, devices and conditions. Those skilled in the art may adjust and modify these devices and conditions according to the specific requirement, and these adjustments or modifications made are still included in the scope of the appended claims. 
       DETAILED DESCRIPTION OF EMBODIMENTS 
       [0026]    A set of saw blade provided by the present invention will be described hereinafter in detail combined with drawings and embodiments. In the following descriptions, diverse aspects of the present invention will be described. However, those skilled in the art can use only some or all of the structures/flows of the present invention to implement the present invention. For definiteness of explanation, particular number, configuration and sequence are illustrated, but it is apparent that the present invention can also be implemented without these particular details. In other cases, the well-known features will not be illustrated, in detail to avoid confusing the present invention. 
       Example 1 
       [0027]    Referring to  FIG. 1 , pair of saw blades  1  comprises a first saw blade  10  and a second saw blade  20 , the two saw blades are coaxially connected side-by-side and move around the same axis  11  in opposite directions. A gap  30  is arranged between the first saw blade  10  and the second saw blade  20 . 
         [0028]    In this example, the first saw blade  10  and second saw blade  20  are of identically sized. The first saw blade  10  comprises a first blade body  12  which is circular with the axis  11  of the first saw blade as the center. A plurality of saw teeth  13  are arranged at the circular periphery of the first blade body  12  and the total number of the saw teeth is 32 in this example; these saw teeth have the same shape and size; each saw tooth is triangular; a certain space  14  is left between any two adjacent saw teeth, and a cutting edge  15  is at the shortest side  16  of the triangular saw tooth. 
         [0029]    The second saw blade  20  comprises a second blade body  22  which is circular with the common axis  11  of the first saw blade and the second saw blade as the center. A plurality of saw teeth  23  are arranged at the circular periphery of the second blade body  22  and the total number of the saw teeth is 32 in this embodiment; these saw teeth have the same shape and size; each saw tooth is triangular; a certain space  24  is left between any two adjacent saw teeth; a cutting edge  25  is at the shortest edge  26  of the triangular saw tooth. 
         [0030]    The saw tooth  13  of the first saw blade  10  and the saw tooth  23  of the second saw blade  20  are arranged in the opposite directions, that is, for the first saw blade  10 , the shortest edge (shortest side)  16  of the triangular saw tooth  13  is on the left side of the longest edge  17  of the triangular saw tooth, while for the second saw blade  20 , the shortest edge  26  of the triangular saw tooth  23  is on the right edge of the longest edge  27 . 
         [0031]    Referring to  FIG. 2  which shows the section view when the first saw blade is matched with the second saw blade, the first saw blade  10  is at the bottom, the second saw blade  20  is at the top, and the gap  30  is arranged between the two saw blades, such that the debris of the cut material can be discharged from the gap  30  when the saw blades are cutting, besides, heat can be dispersed from the gap  30  when the two saw blades are operating at high speed. 
         [0032]    A protrusion  18  protruding toward the direction of the second saw blade  20  is arranged at the blade body  12  of the first saw blade  10  dose to the saw tooth  13 , and a notch  28  corresponding to the protrusion  18  is arranged at the blade body  22  of the second saw blade  20  dose to the saw tooth  23 . As seen from  FIG. 2 , the distance between the protrusion  18  and the side  19  of the first saw blade  10  facing the second saw blade  20 , is less than the sum of the depths of the gap  30  and the notch  28 , and the width of the notch  28  of the second saw blade  20  is greater than the width of the protrusion  18 . Such design is aimed at the case that the pair of saw blades are deformed slightly after using for a long time, and due to designated gap left between the protrusion  18  and the notch, the first saw blade  10  and the second saw blade  20  would not interfere with each other even though the deformation is caused. 
         [0033]    Referring to  FIG. 3 , which shows the side  19  of the first saw blade  10  facing the second saw blade  20 , an annular convex rib (protrusion)  18  is arranged at the first blade body  12  of the first saw blade  10  dose to the saw tooth  13 , and the annular convex rib  18  and the first blade body  12  are concentric circles with the same center, that is, the axis  11  of the first saw blade  10  and the second saw blade  20 . 
         [0034]    Referring to  FIG. 4 , which shows the side  29  of the second saw blade  20  facing the first saw blade, an annular notch  28  is arranged at the second blade body  22  of the second saw blade  20  dose to the saw tooth  23 , and the annular convex notch  28  and the second blade body  22  are concentric circles with the same center, that is, the axis  11  of the first saw blade  10  and the second saw blade  20 . 
       Example 2 
       [0035]    Referring to  FIG. 5 , this example is similar to Example 1, the difference lies in that a plurality of bumps  181  are arranged at the side  19  of the first blade body  12  of the first saw blade  10  facing the second saw blade  20  in this example, the ring formed by the bumps  181  in series and the first blade body  12  have a common center, that is, the common axis  11  of the first saw blade  10  and the second saw blade  20 . 
         [0036]    The bumps  181  are circles in the same shape and of the identically sized, and the second saw blade  20  matching with the bumps  181  is shown in  FIG. 4 . The notch  28  of the second saw blade  20  is shown in  FIG. 4 . The diameter of the bump  181  is smaller than the width of the notch  28 , and the height between the bump  181  and the side  19  of the first blade body  12  facing the second saw blade  20  is smaller than the depth of the notch  28 . Such design is aimed at the case that the pair of saw blades are deformed slightly after using for a long time, but due to the space left between the protrusion  18  and the notch, the first saw blade  10  and the second saw blade  20  do not interfere with each other even though the deformation is caused. 
       Example 3 
       [0037]    Referring to  FIG. 6 , this example is similar to Example 1, the difference lies in that a plurality of convex strips  182  are arranged at the side  19  of the first blade body  12  of the first saw blade  10  facing the second saw blade  20  in this example, the ring formed by the convex strips  182  and the first blade body have a common center, that is, the common axis  11  of the first saw blade  10  and the second saw blade  20 . 
         [0038]    There are at least two the convex strips  182  which are all circular convex strips in the same shape and of the same size and the second saw blade  20  matching with the convex strips  182  is shown in  FIG. 4 . For the notch  28  of the second saw blade  20 , the width of the convex strip  182  is smaller than the width of the notch  28 , and the height between the convex strips  182  and the side  19  of the first blade body  12  facing the second saw blade  20  is smaller than the sum of the depth of the gap  30  between the first saw blade  10  and the second saw blade  20  and the depth of the notch  28 . Such design is aimed at the case that the pair of saw blades is deformed slightly after using for a long time, but due to the space left between the protrusion  18  and the notch, the first saw blade  10  and the second saw blade  20  do not interfere with each other even though the deformation is caused. 
         [0039]    Finally, it should be noted that the embodiments above are merely intended to describe the technical solutions of the present invention, rather than limit the technical method, the present invention can be extended to other modifications, changes, applications and embodiments in terms of application, and it is therefore deemed that all such modifications, changes, applications and embodiments shall be included within the scope of the spirits and teachings of the present invention.