Patent Publication Number: US-2022219243-A1

Title: Tool body

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application relates to and claims priority from Japanese Patent Application No. 2021-003636, filed on Jan. 13, 2021, the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     Field 
     The present invention relates to a tool body which fixes an indexable cutting insert. 
     Description of Related Art 
     A tuning tool includes an indexable cutting insert and a tool body which fixes the cutting insert. The cutting insert is fixed to an insert mounting seat of the tool body by a clamp screw or the like inserted from one of end surfaces to the other of the end surfaces (see WO 2016/186113, for example). 
     SUMMARY 
     When the cutting insert is to be fixed by the clamp screw, a left-hand screw, instead of a right-hand screw, is used in some cases depending on a direction of cutting resistance that the cutting insert receives. When the cutting insert described in WO 2016/186113 is mounted on a comb-shaped flat turret of an automatic lathe so as to be used for grooving, if the fixing is implemented by the right-hand screw, there is a concern that the screw is loosened by cutting resistance and thus, the fixing is implemented by the left-hand screw in some cases. If the left-hand screws and the left-hand screws are mixed at a manufacture site, it is necessary to confirm at each use whether the direction is for tightening or loosening the screw, whereby a labor of a worker is increased. 
     Moreover, in a state where the tuning tool is mounted on the comb-shaped flat turret, the worker cannot easily withdraw the clamp screw from a direction opposed to the insert mounting seat since other tuning tools or inner walls of the machine become obstruction in some cases. In a case where a clearance between the inner wall of the machine and the insert mounting seat is extremely small, the tuning tool is removed from the comb-shaped flat turret and the cutting insert is replaced and then, the tuning tool is mounted on the comb-shaped flat turret. Alternatively, by using a clamp screw in which a wrench hole is formed not only in a head part but also at a distal end of a shaft part, the shaft part exposed to a side surface on the opposite side to the side surface on which the insert mounting seat is located is rotated by a wrench, whereby the cutting insert is replaced. 
     In the latter case, since the clamp screw can be removed from the opposite side to the insert mounting seat, there is a merit that the cutting insert can be replaced even if the tool body is not removed from the comb-shaped tool rest. On the other hand, in the latter case, when the cutting insert is to be removed from the tool body, there is a concern that the clamp screw is dropped together with the used cutting insert into a spot, which is located below the comb-shaped tool rest in the machine and where chips are treated/discarded, and lost in some cases. 
     Therefore, the present invention has an object to provide a tool body in which a cutting insert can be easily replaced. 
     A tool body according to one aspect of the present invention is a tool body fixing an indexable cutting insert and has an insert mounting seat which is provided on a first surface of the tool body, a clamp member which binds the cutting insert placed on the insert mounting seat, and an operating member which operates the clamp member. The operating member can lower the clamp member in a direction from the first surface toward a second surface of the tool body on an opposite side thereof to the first surface and can raise the clamp member from the second surface toward the first surface. The clamp member has a hook portion brought into contact with a diameter reducing portion formed on an inner peripheral surface of a mounting hole of the cutting insert in a state where the clamp member is lowered. 
     According to this aspect, by raising the clamp member and by having a clearance between the hook portion and the cutting insert, the cutting insert can be removed. Since there is no need to completely withdraw the clamp member from the insert mounting seat at each replacement of the cutting insert, fall of the clamp member during a replacement work for the cutting insert can be prevented. Therefore, the tool body in which the cutting insert can be easily replaced can be provided. 
     In the aforementioned aspect, at least a part of the operating member may be exposed to the second surface side. 
     According to this aspect, the cutting insert can be replaced by an operation from the second surface side opposite to the insert mounting seat. The cutting insert in which the cutting insert can be easily replaced even by a wall or the like where a hand cannot easily reach the insert mounting seat can be provided. 
     In the aforementioned aspect, in the state where the clamp member binds the cutting insert, it may be so constituted that the clamp member includes a protruding portion located closer to the first surface side than a bottom surface of the cutting insert and an embedded portion located closer to the second surface side than the bottom surface of the cutting insert, a hook portion is provided on the protruding portion, a tail portion protruding toward an opposite side to the hook portion, when seen from the first surface side, is provided on the embedded portion, the insert mounting seat has a pocket which accommodates the embedded portion, and an inclined surface which supports the tail portion is formed in the pocket. 
     According to this aspect, when the clamp member is lowered, the clamp member is elastically deformed slightly, and the hook portion is rotationally moved with the tail portion as a fulcrum. Since contact between the hook portion and the cutting insert is stable, the tool body can bind the cutting insert more reliably. 
     In the aforementioned aspect, the tail portion may be constituted by a part of a columnar surface or a part of a spherical surface at a portion supported by the inclined surface. 
     According to this aspect, since a lower surface of the tail portion and the inclined surface are in point-contact, a position of the fulcrum is stabilized. Since the hook portion is brought into contact with the cutting insert stably in compliance with a design, the tool body can bind the cutting insert more reliably. 
     In the aforementioned aspect, in the clamp member, a female thread having an axis in parallel with a center axis of the mounting hole of the cutting insert may be formed, and a male thread screwed with the female thread may be formed in the operating member. 
     According to this embodiment, a simple constitution of the male thread and the female thread can constitute the operating member which lowers/raises the clamp member. The cutting insert is not directly fixed by the male thread but fixed through the clamp member and thus, the direction of the screw can be selected not depending on the direction of cutting resistance. 
     In the aforementioned aspect, it may be so constituted that the operating member has the shaft portion on which the male thread is formed and a head portion provided on one end of the shaft portion and formed having a diameter larger than that of the shaft portion, and a seat surface of the head portion which connects an outer edge of the shaft portion and an outer edge of the head portion is formed having a conical shape or a semispherical shape, and a recess portion having a shape following the seat surface of the head portion is formed on the second surface. 
     According to this aspect, as the operating member which is a screw member is tightened, the head portion of the screw is guided to the recess portion, and the shaft portion of the screw is positioned with respect to the insert mounting seat. Thus, the clamp member connected to the operating member and the cutting insert placed on the insert mounting seat can be positioned easily. 
     In the aforementioned aspect, the hook portion has a center portion and a first end portion as well as a second end portion located on opposite sides to each other, with the center portion between them, and while the center portion is not in contact with the cutting insert, the first end portion and the second end portion may be brought into contact with the cutting insert. 
     The shape of the distal end of the hook portion and the shape of the mounting hole of the cutting insert have slight variation allowed as a tolerance. According to this aspect, even if the shapes of the hook portion and the mounting hole are slightly varied, since the hook portion is brought into contact with the inner peripheral surface of the diameter reducing portion reliably at two points, binding of the cutting insert by the clamp member is stabilized. 
     According to the present invention, the tool body in which the cutting insert can be replaced easily can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating an example of a tuning tool according to an embodiment of the present invention; 
         FIG. 2  is a perspective view illustrating the tuning tool shown in  FIG. 1  in an exploded manner; 
         FIG. 3  is a perspective view illustrating a distal end portion shown in  FIG. 1  in an enlarged manner; 
         FIG. 4  is a sectional view in which the distal end portion shown in  FIG. 3  is cut on a symmetry plane of a clamp member; 
         FIG. 5  is a perspective view of the clamp member shown in  FIG. 4  when seen from a hook portion side; 
         FIG. 6  is a perspective view of the clamp member shown in  FIG. 4  when seen from a tail portion side; 
         FIG. 7  is a plan view of the clamp member shown in  FIG. 4  when seen from a first surface side; and 
         FIG. 8  is a perspective view illustrating a state where binding is loosened and a cutting insert is removed. 
     
    
    
     DETAILED DESCRIPTION 
     A preferred embodiment of the present invention will be described by referring to the attached figures. In each figure, those given the same signs have the same or similar constitutions. Hereinafter, each constitution will be described in detail by referring to the figures.  FIG. 1  is a perspective view illustrating an example of a tuning tool  1  according to an embodiment of the present invention. The tuning tool  1  includes an indexable cutting insert  2  and a tool body  3  which fixes the cutting insert  2 . In the illustrated example, the tuning tool  1  is constituted as a grooving tool for an automatic lathe fixed to a comb-shaped tool rest. 
       FIG. 2  is a perspective view illustrating the tuning tool  1  shown in  FIG. 1  in an exploded manner. As shown in  FIG. 2 , a tool body  3  includes a holder  4 , a clamp member  6  mounted on the holder  4 , and an operating member  7 . The holder  4  is formed having a rod shape extending from a base end  41 E to a distal end  42 E on a side opposite to the base end  41 E. 
     In the distal end portion  42  of the holder  4  including the distal end  42 E and a portion in the vicinity thereof, an insert mounting seat  5  on which the cutting insert  2  is placed is provided. A portion closer to the base end  41 E side than the distal end portion  42  is constituted as a shank which can be fixed to a machine tool. The insert mounting seat  5  has a seating surface  52  which is brought into contact with a bottom surface (a second end surface  22 , for example) of the cutting insert  2  and binds the cutting insert  2 , which will be described later, and a wall surface  53  which is brought into contact with a peripheral side surface  23  of the cutting insert  2  and binds the cutting insert  2 , which will be described later. 
       FIG. 3  is a perspective view illustrating the distal end portion  42  shown in  FIG. 1  in an enlarged manner. As shown in  FIG. 3 , the distal end portion  42  has a distal end surface  425  and first to fourth surfaces  421 ,  422 ,  423 , and  424  faced with the distal end surface  425 . The aforementioned distal end  42 E of the holder  4  is located on the distal end surface  425 . The aforementioned insert mounting seat  5  is provided on the first surface  421 . The second surface  422  is located on a side opposite to the first surface  421 . The third and fourth surfaces  423  and  424  connect the first surface  421  and the second surface  422 . 
     In the following description, a direction from the first surface  421  to the second surface  422  in a height direction Dh of the holder  4  is referred to as downward, and a direction from the second surface  422  to the first surface  421  in the height direction Dh is referred to as upward in some cases. The height direction (up-and-down direction) Dh of the holder  4  is a direction connecting the first surface  421  and the second surface  422  of the distal end portion  42 , and it does not necessarily have to be orthogonal to a longitudinal direction DL of the holder  4  connecting the base end  41 E and the distal end  42 E of the holder  4 . 
     As shown in  FIG. 3 , the clamp member  6  binds the cutting insert  2  placed on the insert mounting seat  5 . The cutting insert  2  has a first end surface  21 , a second end surface  22  on a side opposite to the first end surface  21 , a peripheral side surface  23  connecting the first end surface  21  and the second end surface  22 , and a mounting hole  29  penetrating the first end surface  21  and the second end surface  22 . The peripheral side surface  23  includes a cutting edge  24  which cuts an workpiece material to be cut and a rake face  25  as well as a flank  26  faced with the cutting edge  24 . 
     At least a part of the second end surface  22  is constituted as a bottom surface supported by the seating surface  52  of the insert mounting seat  5 . In the illustrated example, the first end surface  21  and the second end surface  22  have substantially the same shape. Thus, by inverting the cutting insert  2  upside down so that the first end surface  21  becomes the bottom surface, the cutting insert  2  can be attached to the insert mounting seat  5 . 
     In the illustrated example, the peripheral side surface  23  is formed symmetrically by 180 degrees to a center axis Z of the mounting hole  29 . The peripheral side surface  23  includes four cutting edges  24  (see  FIG. 8 ) in total, that is, two cutting edges  24  which can be used when the cutting insert  2  is attached to the insert mounting seat  5  with the second end surface  22  as the bottom surface and two cutting edges  24  which can be used when the cutting insert  2  is attached to the insert mounting seat  5  with the first end surface  21  as the bottom surface. 
       FIG. 4  is a sectional view in which the distal end portion shown in  FIG. 3  is cut on the symmetry plane of the clamp member  6 . A position of the section is indicated by a IV-IV line in  FIG. 3 . As shown in  FIG. 4 , an inner peripheral surface of the mounting hole  29  of the cutting insert  2  has a large diameter portion  291  and a diameter reducing portion  292  whose inner diameter is smaller than that of the large diameter portion  291 . In the illustrated example, the large diameter portion  291  is formed on each of the first end surface  21  and the second end surface  22 , and the diameter reducing portion  292  is formed in an intermediate portion of the first end surface  21  and the second end surface  22 . 
     The clamp member  6  has a hook portion  61  in contact with the diameter reducing portion  292  and a tail portion  62  in contact with the insert mounting seat  5 .  FIG. 5  is a perspective view of the clamp member  6  illustrated in  FIG. 4  when seen from the hook portion  61  side. As shown in  FIG. 5 , the clamp member  6  has a columnar barrel portion  60  extending in the height direction Dh of the holder  4 . The aforementioned hook portion  61  and the tail portion  62  are provided on the barrel portion  60 . 
       FIG. 6  is a perspective view of the clamp member  6  illustrated in  FIG. 4  when seen from the tail portion  62  side. In the illustrated example, a female thread (screw hole)  67  is formed on a bottom surface of the barrel portion  60 . The female thread  67  is formed so that an axis thereof is in parallel with the center axis Z of the mounting hole  29  (shown in  FIG. 4 ) of the cutting insert  2 . As shown in  FIG. 6 , a lower surface  622  of the tail portion  62  is gently curved so as to expand downward. In the illustrated example, the lower surface  622  has a center axis perpendicular to the symmetry plane of the clamp member  6  and a is constituted by a part of the columnar surface with a large radius of a curvature circle. The lower surface  622  may be constituted by a part of a spherical surface with a large radius of the curvature circle. 
       FIG. 7  is a plan view of the clamp member  6  illustrated in  FIG. 4  when seen from the first surface  421  side of the distal end portion  42  of the holder  4 . As shown in  FIG. 7 , when seen from the first surface  421  side, that is, when seen from above, the tail portion  62  protrudes toward the side opposite to the hook portion  61 . The distal end of the hook portion  61  has a center portion  613  and first and second end portions  611  and  612  located on sides opposite to each other with the center portion  613  between them. 
     The hook portion  61  is formed with the first and second end portions (both end portions)  611  and  612  extending angularly so that the center portion  613  is not brought into contact with the cutting insert  2 , while the first and second end portions  611  and  612  are brought into contact with the diameter reducing portion  292  of the cutting insert. In more detail, an outer shape of the distal end of the hook portion  61  when seen from the first surface  421  side is formed such that the center portion  613  sandwiched by the first and second end portions  611  and  612  has an arc shape whose radius of the curvature circle is larger than a protruding portion  601  of the barrel portion  60  which will be described later, and each of the first and second end portions  611  and  612  is formed having the arc shape whose radius of the curvature circle is smaller than the protruding portion  601 . 
     By referring to  FIG. 4  again, the operating member  7  will be described. The operating member  7  can lower the clamp member  6  from the first surface  421  toward the second surface  422  in the height direction Dh of the holder  4  or raise the clamp member  6  from the second surface  422  toward the first surface  421 . In the illustrated example, the operating member  7  is constituted as a screw member having a shaft portion  72  on which a male thread is formed and a head portion  71  provided on one end of the shaft portion  72  and having a diameter larger than that of the shaft portion  72 . The male thread of the shaft portion  72  is formed so as to be screwed with the female thread  67  of the clamp member  6 . 
     Note that the operating member  7  is not limited to a screw member screwed with the clamp member  6 . It may be a worm gear or other transmission mechanisms as long as it can lower/raise the clamp member  6 . In the illustrated example, in the screw member, a seat surface of the head portion  71  which connects an outer edge of the shaft portion  72  and the outer edge of the head portion  71  is formed having a conical shape. The shape of the seat surface may be semispherical. On the second surface  422  of the holder  4 , a recess portion  58  having a shape following the seat surface of the head portion  71  is formed. 
     The hook portion  61  described above is brought into contact with the diameter reducing portion  292  formed inside the mounting hole  29  of the cutting insert  2  in the state where the clamp member  6  has been lowered and is separated from the diameter reducing portion  292  in the state where the clamp member  6  is raised. The aforementioned barrel portion  60  includes the protruding portion  601  located closer to the first surface  421  side than the bottom surface of the cutting insert  2  (the second end surface  22  in the illustrated example) and an embedded portion  602  located closer to the second surface  422  side than the bottom surface in the state where the clamp member  6  binds the cutting insert  2 . 
     The hook portion  61  is provided on the protruding portion  601 , and the tail portion  62  and the female thread  67  are provided on the embedded portion  602 . In the protruding portion  601 , a portion on a side opposite to the hook portion  61  is formed as an inclined surface which gets closer to the hook portion  61  as it goes from the second surface  422  side toward the first surface  421  side. Though the hook portion  61  protrudes to the radial direction of the mounting hole  29  of the cutting insert  2  in the protruding portion  601 , the portion on the opposite side is formed as the inclined surface and thus, the distal end portion on the first surface  421  side of the protruding portion  601  does not have an expanded shape. Therefore, the hook portion  61  can be smoothly inserted/removed with respect to the mounting hole  29 . In the state where the clamp member  6  is loosened, the cutting insert  2  can be removed from the insert mounting seat or the cutting insert  2  can be mounted on the insert mounting seat  5 . 
     In the insert mounting seat  5 , a pocket  56  which accommodates the embedded portion  602  is provided. In the pocket  56 , an inclined surface  561  which supports a lower surface  622  of the tail portion  62  and a through hole  57  penetrating from a bottom surface of the pocket  56  to the second surface  422  is formed. As described above, the lower surface  622  of the tail portion  62  is expanded downward. On the other hand, the inclined surface  561  of the insert mounting seat  5  is formed having a planar shape. Therefore, a contact area between the lower surface  622  and the inclined surface  561  is small. As shown in  FIG. 4 , at least a part of the operating member  7  is exposed to the second surface  422  side. In the illustrated example, the shaft portion  72  of the operating member  7  is inserted through the through hole  57  of the pocket  56 , and the head portion  71  of the operating member  7  is exposed to the second surface  422  side. 
     According to the tool body  3  of this embodiment constituted as above, by using the clamp member  6  raised to the first surface  421  side and lowered to the second surface  422  side, the cutting insert  2  can be bound.  FIG. 8  is a perspective view illustrating a state where the binding is loosened, and the cutting insert  2  is removed. By raising the clamp member  6  and loosening the binding, the cutting insert  2  can be removed or mounted and thus, as shown in  FIG. 8 , the clamp member  6  or the operating member  7  does not have to be removed from the holder  4  at each replacement of the cutting insert  2 . As compared with a screw-on type, there is no concern that the clamp screw is removed and lost, and the cutting insert  2  can be easily replaced even in a narrow space. 
     As shown in  FIG. 4 , since the operating member  7  which lowers/raises the clamp member  6  is exposed to the second surface  422  side opposite to the insert mounting seat  5 , the cutting insert  2  can be replaced by an operation from the second surface  422  side. Even in the case where the cutting insert  2  cannot be replaced easily from the direction opposed to the insert mounting seat  5  due to obstruction by the comb-shaped tool rest or the like, the cutting insert  2  can be replaced without removing the tool body  3  from the comb-shaped tool rest. 
     When the clamp member  6  is rotationally moved, as shown in  FIG. 4 , since the rotation center is positioned by the tail portion  62  which is used as a fulcrum, a position where the hook portion  61  is brought into contact with the cutting insert  2  is stabilized. As shown in  FIG. 6 , since the lower surface  622  of the tail portion  62  is expanded, and the contact area with the inclined surface  561  of the insert mounting seat  5  is small, the rotation center of the clamp member  6  can be easily disposed in a narrow region as designed. 
     The embodiment described above is for facilitating understanding of the present invention and is not intended to interpret the present invention in a limited manner. Each of the elements included in the embodiment, dispositions, materials, conditions, shapes, sizes and the like thereof are not limited to the illustrated but can be changed as appropriate. Moreover, constitutions illustrated in different embodiments can be partially substituted or combined.