BACKGROUND OF THE INVENTION 0001 1. Field of the Invention 0002 The present invention relates generally to a cutting tool, and more particularly to a circular blade of the cutting tool. 0003 2. Description of Related Art 0004 As shown in FIGS. 1, 2A, and 3A, a prior art circular blade 11 of a cutting tool 10 is made integrally and is provided at the center thereof with a fastening hole 12. The circular blade 11 is fastened to one end of a handle 16 by a fastening bolt 13 and a nut 15. The fastening bolt 13 is engaged with the nut 15 via the fastening hole 12 of the circular blade 11. The prior art circular blade 11 is defective in design in that it is susceptible to a minute deformation in the course of finishing process, and that its structural strength is inadequate. In addition, the prior art circular blade 11 does not work smoothly due to the mechanical friction between the circular blade 11 and other component parts of the cutting tool 10. 0005 As shown in FIGS. 2B and 3B, another prior art circular blade 40 is provided with a recess 401, which is intended to alleviate the deformation that is caused in the finishing process. However, the working of this prior art circular blade 40 is hampered by the mechanical friction between the planar portion 402 of the circular blade 40 and other component parts of the cutting tool. In addition, the structural strength of the circular blade 40 is insufficient to meet the work requirement.

BRIEF SUMMARY OF THE INVENTION 0006 It is the primary objective of the present invention to provide a circular blade which is free of the deficiencies of the prior art circular blades described above. 0007 In keeping with the principle of the present invention, the foregoing objective of the present invention is attained by the circular blade having a fastening hole, a reinforcing portion, and a cutting edge. The reinforcing portion serves to strengthen the structure of the circular blade, reduce the contact area between the circular blade and other component parts of the cutting tool, and prevent the deformation of the circular blade in the course of finishing process. 0008 The foregoing objective, feature and function of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of the present invention with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 0009 FIG. 1 shows an exploded view of a cutting tool of the prior art. 0010 FIG. 2A shows a sectional view of a circular blade of the prior art cutting tool as shown in FIG. 1. 0011 FIG. 2B shows a sectional view of another prior art circular blade. 0012 FIG. 3A shows a perspective view of the prior art circular blade as shown in FIG. 2A. 0013 FIG. 3B shows a perspective view of the prior art circular blade as shown in FIG. 2B. 0014 FIG. 4 shows a perspective view of a circular blade of the present invention. 0015 FIG. 5 shows an exploded view of a cutting tool comprising the circular blade of the present invention as shown in FIG. 4. 0016 FIG. 6 shows a sectional view of the circular blade of the present invention and other component parts of the cutting tool as shown in FIG. 5. 0017 FIG. 7 shows a sectional view of the circular blade of the present invention. 0018 FIGS. 8A, 8B, 8C, and 8D are schematic views to show that the circular blade of the present invention has a regularly-serrated cutting edge or an irregularly-serrated cutting edge.

DETAILED DESCRIPTION OF THE INVENTION 0019 As shown in FIGS. 4-7, a circular blade 20 of the present invention is provided in the center with a fastening hole 21 to facilitate the fastening of the circular blade 20 to one end of a cutting tool handle 31 by a locating element 30 and a nut 33, as illustrated in FIG. 5. 0020 The circular blade 20 of the present invention is further provided with a reinforcing portion 22 having a predetermined width and thickness. In other words, the reinforcing portion 22 is raised from the surface of one side of the circular blade 20 such that the reinforcing portion 22 circumvents the fastening hole 21. 0021 The circular blade 20 of the present invention has a cutting edge 23, which is regularly serrated, or irregularly serrated, as illustrated in FIGS. 8A-8D. 0022 The reinforcing portion 22 serves to strengthen the structure of the circular blade 20 of the present invention, and to prevent the deformation of the circular blade 20 in the finishing process. When the circular 20 is being finished, the reinforcing portion 22 serves to eliminate the metal internal stress, thereby preventing the deformation of the circular blade 20. 0023 As shown in FIG. 6, the reinforcing portion 22 serves to reduce the contact area between the circular blade 20 of the present invention and the cutting tool handle 31 to which the circular blade 20 is fastened by the locating element 30 in conjunction with the nut 33. 0024 The present invention described above is to be regarded in all respects as being merely illustrative, and not restrictive. Accordingly, the present invention may be embodied in other specific forms without deviating from the spirit thereof. The present invention is therefore to be limited only by the scope of the following claim.