Patent Publication Number: US-2003233927-A1

Title: Circular saw blade for cutting ferrous materials

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates generally to circular saw blades, and more particularly to circular saw blades including inserts adapted for cutting ferrous material.  
       BACKGROUND  
       [0002] It is known in the art to have saw blades adapted to cut ferrous material such as steel studs. These saw blades may or may not include inserts of a hardened material to increase cutting ability. Generally, saw blades that include inserts have carbide tips that are adapted to tear-away or chop-away small portions of metal at a time.  
       [0003] Generally, these inserts are formed separately and machined or cut before being fit into the saw blade. The machining or forming of the inserts generally includes extensive angles or other shapes being formed into the insert itself. The different forms of the angles and shapes are generally believed to create a greater efficiency in the cutting of a material. However, in creating such numerous indentations and angles in the face or edges of the insert creates additional steps and increased labor in the production of the inserts. Furthermore, an inventory of each individual insert must be kept on hand for saw blade production.  
       SUMMARY OF THE INVENTION  
       [0004] The present invention includes a circular saw blade which includes a plurality of teeth situated on the perimeter thereof. Each of the plurality of teeth includes an insert formed of a hardened material, preferably carbide. Each of the inserts includes a leading face which terminates at a cutting edge at the upper radial edge of the insert. The cutting edge is defined by an angled surface which includes a shorter side and a longer side. The inserts are arranged such that adjacent inserts have an alternating pattern such that the shorter side of the angled surface is alternated to different sides of the blade.  
       [0005] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes 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  
     [0006] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
     [0007]FIG. 1 is a plan view of a circular saw blade including carbide inserts on the teeth according to the principles of the present invention;  
     [0008]FIG. 2 is a detail side view of a saw blade tooth;  
     [0009]FIG. 3 a  is a front detail of a singular insert according to the principles of the present invention; and  
     [0010]FIG. 3 b  is a top plan view of a single insert according to the principles of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0011] With reference to FIGS.  1 - 3 , a circular saw blade  10  is disclosed. The circular saw blade  10  includes a body  12 , having two sides  13   a  and  13   b  (only one side is shown in FIG. 1). The saw blade  10  is designed to turn in the direction of arrow A about an axis of rotation  14 . Teeth  16  are formed around the perimeter of the body  12 . As best shown in FIG. 2, the teeth  16  each include a shoulder  18  each separated by a gullet  20 . An insert  22 , 22 ′ is affixed to each of the respective shoulders  18 . The gullet  20  is an open area that is formed by an arc  24  where a hip  26  of a preceding tooth  16  extends over the arc  24  of the gullet  20 . The arc  24  terminates at the leading face  28  of an insert  22 . The leading face  28  of the inserts  22 , 22 ′ are generally parallel with a radius  30  of the circular saw blade  10 . The radius  30  extends from the axis of rotation  14  at the center of the circular saw blade  10 . The distal radial edge of the inserts  22 , 22 ′ include a cutting edge  32 , 32 ′ best shown in FIG. 3, which defines an upper end of the cutting edge of the insert  22 .  
     [0012] The inserts  22 , 22 ′ are affixed to the tooth  16  through welding, soldering or other suitable means. Thus, the saw blade turns about the axis of rotation  14  in the direction of arrow A so that the leading face  28  of the inserts  22 , 22 ′ may engage a material to be cut.  
     [0013] With reference to FIGS. 3 and 3 a , the detail of a singular insert  22  is shown. The upper cutting edge of the leading face  28  of the insert  20  includes a cutting edge  32 . The insert  22  further includes two sides  34 ,  36  and a base  38  extending between the sides  34 ,  36 . The cutting edge of the leading face  28  has a width of approximately 1.75 mm with each of the sides  34 ,  36  tapering inward approximately 0.09 mm at the base end  38 . The cutting edge  32  is created by two edge surfaces  40 ,  42  which terminate into respective sides  34 ,  36  of the insert  22 . The first edge surface  40  is generally perpendicular to the axis of rotation  14  of the blade  10 . The second angled edge surface  42  is ground at approximately a 10-30° angle “x”, preferably approximately 20° across approximately one third of the tooth width thus forming angled surface  42 . The first and second edge surfaces  40 , 42  interface along line  43 , as best shown in FIG. 3 a . The inserts  22 ′, have a leading face  28  which is a mirror image of the leading face  28  of the inserts  22  and are placed on alternating teeth around the periphery of the saw blade  10 . In other words, the angled second edge surface  42  of the cutting edges  32 , 32 ′ of inserts  22 , 22 ′ respectively are disposed on alternate sides  13   a , 13   b  of the blade along the circumference of the circular saw blade  10 .  
     [0014] As the circular saw blade  10  rotates about the axis of rotation  14  each alternating cutting edge  32 ,  32 ′ takes material from a different side of the channel being cut.  
     [0015] Preferably, the insert  20  is formed of a carbide material including, preferably, 8.6% TiC, 12% Ta(Nb)C, and 9.5% Co. Furthermore, the average preferred grain size of the carbide material would be in the range of 1-1.5 micrometers in diameter.  
     [0016] The cutting edges  32 , 32 ′ of the inserts  22 , 22 ′ preferably have a back angle “y” of between 5° and 15° and preferably 10°, as illustrated in FIG. 2. The back angle of the inserts  22 , 22 ′ leads into a curved upper (or peripheral) surface  44  of the teeth  16 . The curved upper surface  44  terminates into the hip  26  which provides a rounded surface transitioning into the arc  24  of the gullet. According to a preferred embodiment, the hip  26  is spaced a distance d from a tangent line of adjacent cutting edge tips  32 , 32 ′ of approximately 0.5 mm.  
     [0017] 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.