Patent Publication Number: US-2007095190-A1

Title: Disk cutter with plurality of thicker portions

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a disk cutter or circular saw suitable for cutting of steel, wood, ALC (autoclaved lightweight concrete), woody cement, etc.  
      2. Description of the Related Art  
      A disk cutter or circular saw including a base disk having a plurality of tip supports arranged along the outer circumference and a plurality of hardened cutting tip inserts (cutter inserts) respectively fixed to the tip supports by brazing or the like is frequently used for board cutting or the like. A plurality of the tip supports are spaced at given intervals in the circumferential direction of the base disk or annular disk-shaped base, and a gullet is defined between adjacent ones of the tip supports. Each tip support has a recess, and each hardened cutting tip insert is fixed in the recess of the corresponding tip support by brazing or the like.  
      The base disk has a first mounting hole at its central portion, and a boss portion of a collar is inserted through the first mounting hole. The boss portion of the collar is formed with a second mounting hole, and a rotating shaft of a rotary tool is inserted through the second mounting hole. The disk cutter is mounted to the rotary tool by fastening the base disk through the collar to the rotating shaft with a bolt.  
      The annular disk-shaped base of such a disk cutter has a small thickness as compared with its outer diameter. Accordingly, resonance or transverse vibration occurs under a certain condition in cutting a work material or in idling, causing not only a high level of noise, but also a remarkable degradation in cutting performance.  
      To suppress the resonance or transverse vibration in cutting a work material, Japanese Patent Laid-open No. Hei 10-296529 has proposed a disk cutter or circular saw wherein a vibration suppression plate is fixed to a side surface of the disk-shaped base by means of bolts and nuts. In this related art disk cutter, the vibration suppression plate as a separate member is fixed to a side surface of the disk-shaped base by means of bolts and nuts. Accordingly, the structure of the disk cutter is complicated and the weight of the disk cutter is also increased. Further, there is a case that the size of a work material to be cut is limited.  
     SUMMARY OF THE INVENTION  
      It is therefore an object of the present invention to provide a disk cutter which can suppress the transverse vibration in cutting a work material with a simple structure without an increase in weight.  
      In accordance with an aspect of the present invention, there is provided a disk cutter comprising an annular disk-shaped base adapted to be driven about an axis of rotation, the base having a first thickness; a plurality of tip supports formed along the outer circumference of the base integrally therewith so that a gullet is defined between adjacent ones of the tip supports; a plurality of tip inserts respectively fixed to the tip supports, each of the tip inserts having a second thickness; and a plurality of thicker portions each formed along a trailing end of each tip support in respect of rotation of the base, the thicker portions having a third thickness; the third thickness being greater than the first thickness and less than the second thickness.  
      Preferably, the thicker portion is formed by plastic deformation, e.g., hot forging of the outer circumference of each tip support.  
      In accordance with another aspect of the present invention, there is provided a disk cutter including an annular disk-shaped base adapted to be driven about an axis of rotation, the base having a first thickness; a plurality of tip supports formed along the outer circumference of the base integrally therewith so that a gullet is defined between adjacent ones of the tip supports; a plurality of tip inserts respectively fixed to the tip supports, each of the tip inserts having a second thickness; and a plurality of thicker portions each continuously formed over the range from the outer circumference of each tip support to the inner wall of the gullet between adjacent ones of the tip inserts, the thicker portion having a third thickness; the third thickness being greater than the first thickness and less than the second thickness.  
      In accordance with a fourth aspect of the present invention, there is provided a disk cutter including an annular disk-shaped base adapted to be driven about an axis of rotation, the base having a first thickness; a plurality of tip supports formed along the outer circumference of the base integrally therewith so that a gullet is defined between adjacent ones of the tip supports; a plurality of tip inserts respectively fixed to the tip supports, each of the tip inserts having a second thickness; and a plurality of thicker portions each formed along a trailing end of each of some of the tip supports in respect of rotation of the base, the some of the tip supports being arranged at intervals of two or more tip supports, the thicker portions having a third thickness; the third thickness being greater than the first thickness and less than the second thickness.  
      In accordance with a still further aspect of the present invention, there is provided a disk cutter including an annular disk-shaped base adapted to be driven about an axis of rotation, the base being composed of an inner circumferential portion having a first thickness and an outer circumferential portion having a second thickness greater than the first thickness; a plurality of tip supports formed along the outer circumference of the outer circumferential portion of the base integrally therewith so that a gullet is defined between adjacent ones of the tip supports; and a plurality of tip inserts respectively fixed to the tip supports, each of the tip inserts having a third thickness; the second thickness being less than the third thickness.  
      The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a side view of a part of a disk cutter according to a first preferred embodiment of the present invention;  
       FIG. 2  is an enlarged cross section taken along the line II-II in  FIG. 1 ;  
       FIG. 3  is an enlarged cross section taken along the line III-III in  FIG. 1 ;  
       FIG. 4  is a side view of a part of a disk cutter according to a second preferred embodiment of the present invention;  
       FIG. 5  is a side view of a part of a disk cutter according to a third preferred embodiment of the present invention;  
       FIG. 6  is a side view of a part of a disk cutter according to a fourth preferred embodiment of the present invention;  
       FIG. 7  is an enlarged cross section taken along the line VII-VII in  FIG. 6 ;  
       FIG. 8  is a side view of a part of a disk cutter according to a fifth preferred embodiment of the present invention;  
       FIG. 9A  is a cross section taken along the line IX-IX in  FIG. 8 ; and  
       FIG. 9B  is similar to  FIG. 9A  but showing another embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      A disk cutter  2  according to a first preferred embodiment of the present invention will now be described with reference to FIGS.  1  to  3 . The disk cutter  2  is suitable for cutting of steel, wood, ALC (autoclaved lightweight concrete), woody cement, etc. In this preferred embodiment, the disk cutter  2  includes an annular disk-shaped base (base disk)  4  having an outer diameter of about 185 mm and a reference thickness T 3  of about 1.6 mm and a plurality of (e.g., 48) saw-toothed tip supports  6  formed along the outer circumference of the base disk  4  at equal intervals or unequal intervals. A gullet  8  is defined between adjacent ones of the tip supports  6 . The base disk  4  is formed of steel such as JIS SKS51 (alloy tool steel), JIS SK5 (carbon tool steel), or JIS SK6 (carbon tool steel). Each tip support  6  is formed with a recess  7 , and a tip insert  10  is fixed in each recess  7  by brazing or the like. Each tip insert  10  is formed of cemented carbide.  
      Each tip insert  10  has a face  10   a  having a rake angle of about 0°, a flank  10   b  having a clearance angle C of about 17°, and a cutting edge  10   c  having a transverse clearance angle D (see  FIG. 3 ) of about 4°. The cutting edges  10   c  of any adjacent ones of the tip inserts  10  are oppositely inclined. Further, the side centripetal angle E of each tip insert  10  is set to about 1°, and the thickness of each tip insert  10  is set in such a manner that the thickness T 1  of the cutting edge  10   c  is about 2 mm and the thickness T 2  of a base portion  10   d  is about 1.9 mm. The angles and dimensions of each tip insert  10  are suitably set according to the kind of a work material to be cut.  
      The disk cutter  2  is rotated in a direction shown by an arrow R in  FIG. 1 . Each tip support  6  has a trailing end portion  6   a  in respect of rotation of the disk cutter  2 . The trailing end portion  6   a  is formed with a thicker portion or protruded portion  12  increased in thickness along the thickness of the base disk  4 . The thicker portion  12  is formed by plastic deformation of the trailing end portion  6   a.  For example, the plastic deformation of the trailing end portion  6   a  is performed by hot forging such that the trailing end portion  6   a  is hammered with heat. The thickness T 4  of the thicker portion  12  is set greater than the reference thickness T 3  of the base disk  4  and less than the thickness T 1  of the cutting edge  10   c.  In this preferred embodiment, the thickness T 4  is set to about 1.9 mm, which is almost equal to the thickness T 2  of the base portion  10   d  of each tip insert  10 . While the thicker portion  12  is formed on each tip support  6  in this preferred embodiment, the thicker portion  12  may be formed at intervals of one tip supports  6  or two or more tip supports  6 .  
      Referring to  FIG. 4 , there is shown a side view of a part of a disk cutter  2 A according to a second preferred embodiment of the present invention. In the disk cutter  2 A, each tip support  6  has an inclined trailing end portion  6   a.  The inclined trailing end portion  6   a  is formed with a thicker portion  14  by hot forging. The other configuration is similar to that of the first preferred embodiment shown in  FIG. 1 .  
      Referring to  FIG. 5 , there is shown a side view of a part of a disk cutter  2 B according to a third preferred embodiment of the present invention. In the disk cutter  2 B, a thicker portion  16  is continuously formed over the range from the outer circumference of the tip support  6  to the inner wall of the gullet  8  between adjacent ones of the tip inserts  10 . Further, the trailing end of the thicker portion  16  in respect of rotation of the disk cutter  2 B abuts against the base portion  10   d  of each tip insert  10 . In this preferred embodiment, the thicker portion  16  is formed by hot rolling of the outer circumference of the tip support  6  and the inner wall of the gullet  8 . Although not especially shown, a thicker portion  16   a  formed along the outer circumference of the tip support  6  and a thicker portion  16   b  formed along the inner wall of the gullet  8  may be discontinued in the circumferential direction of the base disk  4 . In other words, the thicker portions  16   a  and  16   b  constituting the thicker portion  16  may be separated from each other. The other configuration is similar to that of the first preferred embodiment shown in  FIG. 1 .  
      Referring to  FIG. 6 , there is shown a side view of a part of a disk cutter  2 C according to a fourth preferred embodiment of the present invention. In the disk cutter  2 C, the base disk  4  is composed of an inner circumferential portion  4   a  having the reference thickness T 3  and an outer circumferential portion  4   b  having a thickness greater than the reference thickness T 3  and equal to the thickness T 2  of the base portion  10   d  of each tip insert  10 . The base disk  4  having such a structure is formed by first preparing a disk having the thickness T 2  and next grinding the inner circumferential portion  4   a  so as to obtain the thickness T 3 . A plurality of tip supports  6 ′ are formed along the outer circumference of the outer circumferential portion  4   b,  and the tip insert  10  is fixed to each tip support  6 ′ by brazing or the like. In this preferred embodiment, the thickness of each tip support  6 ′ is a uniform thickness greater than the thickness T 3  of the inner circumferential portion  4   a  and less than the thickness T 1  of the cutting edge  10   c  of each tip insert  10 . Accordingly, unlike the first to third preferred embodiments, it is not necessary to form a thicker portion on each tip support  6 ′, and it is also not necessary to perform any machining for forming such a thicker portion.  
      Referring to  FIG. 8 , there is shown a side view of a part of a disk cutter  2 D according to a fifth preferred embodiment of the present invention. In the disk cutter  2 D, each tip support  6  is formed with a thicker portion  18  increased in thickness along the thickness of the base disk  4 . The thicker portion  18  is formed by plastic deformation of part of the tip support  6  by hot forging. As shown in  FIG. 9A , a chamfer  18 a is formed at each top corner of the thicker portion  18 . In this embodiment, a difference H 1  between height of the thicker portion  18  and height of the cutting edge  10   c  of the tip insert  10  is set very small, such as 0.35 mm so that the disk cutter  2 D is suitable for cutting steels or other metal works. As the chamfer  18   a  is formed at each top corner of the thicker portion  18 , small tips of the cut work material are less likely to adhere to the thicker portion  18  to thereby prevent the life of the disk cutter  2 D from becoming short. As shown in  FIG. 9B , a notch  18   b  may be formed at each top corner of the thicker portion  18  in place of the chamfer  18   a.    
      In the first to third and fifth preferred embodiments, each tip insert  10  is fixed to the corresponding tip support  6  by brazing after forming the thicker portion  12 ,  14 ,  16  or  18 . Thereafter, each tip insert  10  is polished for finish. In this process, the thickness of the thicker portion  12 ,  14 ,  16  or  18  may be set slightly greater than the thickness T 2  of the base portion  10   d  of each tip insert  10 . Then, in polishing the opposite side surfaces of each tip insert  10  fixed to the corresponding tip support  6 , the opposite side surfaces of the thicker portion  12 ,  14 ,  16  or  18  may be simultaneously polished until the specific thickness of the thicker portion  12 ,  14 ,  16  or  18  is reached. Further, the opposite side surfaces of the thicker portion  12 ,  14 ,  16  or  18  may be formed in parallel to the opposite side surfaces of the base disk  4 . Alternatively, the opposite side surfaces of the thicker portion  12 ,  14 ,  16  or  18  may be inclined with respect to the opposite side surfaces of the base disk  4  at the same angle as the side centripetal angle E of each tip insert  10 .  
      According to each preferred embodiment mentioned above, the thicker portion  12 ,  14 ,  16  or  18  formed on each tip support  6  comes close to a cut groove formed in cutting a work material. Accordingly, in the case that the outer circumference of the base disk  4  transversely vibrates due to the load applied in cutting the work material, the thicker portion  12 ,  14 ,  16  or  18  comes to contact with the inner side surfaces of the cut groove, thereby suppressing the transverse vibration of the base disk  4 . Furthermore, since the thickness of the thicker portion  12 ,  14 ,  16  or  18  is set smaller than the thickness of the cutting edge  10   c  of each tip insert  10 , a contact force between the thicker portion  12 ,  14 ,  16  or  18  and the inner side surfaces of the cut groove in normal operation without the transverse vibration is small, so that an increase in frictional heat can be prevented. Furthermore, since the thicker portion  12 ,  14 ,  16  or  18  is formed by increasing the thickness of the outer circumferential portion of the base disk  4 , an increase in weight of the base disk  4  can be prevented and the structure of the base disk  4  can also be made simple.  
      According to the disk cutter  2 B shown in  FIG. 5 , the thicker portion  16   b  is formed along the inner wall of each gullet  8 . Accordingly, the thicker portion  16   b  comes to contact with the inner side surfaces of the cut groove, thereby enhancing a catching function of each gullet  8  for catching a chip in each gullet  8 . As a result, the chip in each gullet  8  can be efficiently expelled to the outside thereof. This indicates that when a dust collector is mounted to the disk cutter  2 B in cutting a new building material such as ALC and woody cement which is prone to generate dust, a dust collecting efficiency of chips generated from a work material can be increased by the dust collector, thereby improving a work environment.  
      The present invention is not limited to the details of the above described preferred embodiments. The scope of the invention is defined by the appended claims and all changes and modifications as fall within the equivalence of the scope of the claims are therefore to be embraced by the invention.