Abstract:
A temporary coupling mechanism facilitates replacement of a cutting tip in a pocket of a cutting tool, by preventing the cutting tip from falling out of the pocket when a clamping member, e.g., a screw member or wedge member, is loosened. The pocket is provided with a first coupling portion and the cutting tip is provided with a second coupling portion configured to engage the first coupling portion. In one embodiment, the second coupling portion is at least one concave groove or convex portion located in a predetermined position of the cutting tip. A convex portion or a concave groove is provided in at least one of the pocket&#39;s tip mounting seat and the clamping member to engage the concave groove and the convex portion of the cutting tip. The concave groove extends substantially in parallel with the seat face of the tip mounting seat and the convex portion is inserted and fitted into the concave groove so as to be engaged thereto when the cutting tip is inserted into the tip mounting seat and is taken out of the tip mounting seat, causing the cutting tip to be movable only in a predetermined direction relative to the tip mounting seat.

Description:
RELATED APPLICATIONS 
     This is a Continuation-in-Part of International Application No. PCT/JP2009/060286, filed 4 Jun. 2009 and published as WO 2009/148135 on 10 Dec. 2009, which claims priority to JP 2008-146345, filed 4 Jun. 2008. The contents of the aforementioned International and priority applications are incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a temporary coupling mechanism for a cutting tip and an indexable cutting tool equipped with the mechanism. 
     BACKGROUND ART 
     An indexable face milling cutter which is this type of cutting tool has a concave portion at an outer periphery in the front end portion of a tool body to open toward a radial outside of the tool body and a front end side of the tool body. This concave portion is configured to form therein a mounting seat for removably installing a cutting insert (cutting tip) having a cutting blade. A seating member is disposed in the mounting seat and the seating member has a wall face directed at a radial outside of the tool body and a wall face directed at a forward side in a tool rotational direction, which are formed so as to extend toward the front end side of the tool body. The cutting insert is seated on the wall face directed at the forward side in the tool rotational direction of the seating member, and a side face of the cutting insert directed at a radial inside of the tool body contacts with the wall face of the seating member directed at the radial outside of the tool body, thus pressing the cutting insert toward a backward side in the tool rotational direction by a wedge member. See Japanese Patent Laid-Open No. 2007-130738, esp. FIG. 4. 
     In the face milling cutter described in Japanese Patent Laid-Open No. 2007-130738, however, when the cutting insert is inserted into and taken out of the mounting seat by releasing a pressing pressure of the wedge member in a state where the opening of the concave portion in the tool body is directed in the gravity direction, the cutting insert is possibly dropped and missed. Therefore, it can not be easy to perform a replacement operation of a small-size cutting insert or a replacement operation thereof on a machine tool. 
     The present invention is made for solving the aforementioned problem and an object of the present invention is to provide a temporary coupling mechanism for a cutting tip suitable for facilitating a removable operation of a cutting tip to a tip mounting seat and an indexable cutting tool equipped with the mechanism. 
     SUMMARY OF INVENTION 
     The present invention has the following construction for solving the aforementioned problem. 
     The present invention relates to a temporary coupling mechanism for a cutting tip inserted into a tip mounting seat provided in a tool body of a cutting tool, comprising a tip mounting seat including a notch step portion or a concave groove equipped with a seat face and at least one restricting wall face rising up from the seat face, a clamping member for pressing the cutting tip inserted into the tip mounting seat toward the seat face, at least one of a concave groove or at least one convex portion located in a predetermined position of the cutting tip, and a convex portion or a concave groove provided in at least one of the tip mounting seat and the clamping member to be capable of being engaging to the concave groove or the convex portion of the cutting tip, wherein the concave groove extends substantially in parallel with the seat face of the tip mounting seat and the convex portion is inserted and fitted into the concave groove so as to be able to be engaged thereto when the cutting tip is inserted into the tip mounting seat and is taken out of the tip mounting seat, causing the cutting tip to be movable only in a predetermined direction relative to the tip mounting seat. 
     According to the temporary coupling mechanism for the cutting tip, by inserting and fitting the convex portion into the concave groove so as to be able to be engaged thereto when the cutting tip is inserted into the tip mounting seat and is taken out of the tip mounting seat, the movement of the cutting tip in other directions other than the inserting and fitting direction is restricted. In this way, since the cutting tip is not shifted within the tip mounting seat or the cutting tip does not drop out from the tip mounting seat even if gravity is applied in the direction where the movement of the cutting tip is restricted, a removal operation of the cutting tip becomes easy and therefore hours required for the operation are shortened. 
     In the temporary coupling mechanism for the cutting tip, it is preferable that the concave groove extends in a direction along at least the one restricting wall face. With this configuration, since the cutting tip is movable only in the direction along the restricting wall face within the tip mounting seat, the insert and the removal of the cutting tip into and from the tip mounting seat become easy. In consequence, the removal operation of the cutting tip to the tip mounting seat becomes easy and therefore hours required for the operation are shortened. 
     Further, the convex portion may extend or be scattered in a direction along at least the one restricting wall face. With this configuration, the convex portion and the concave groove are engaged to each other in a wide range in the direction along the restricting wall face to stabilize the posture of the cutting tip within the tip mounting seat. In consequence, a removal operation of the cutting tip becomes easy to shorten hours required for the operation, as well as to improve positioning accuracy of the cutting tip. 
     Further, it is preferable to obtain a secure engagement between the convex portion and the concave groove by forming a cross sectional configuration of the convex portion and a cross sectional configuration of the concave groove to be analogous. 
     According to the indexable cutting tool equipped with the temporary coupling mechanism for the cutting tip, by inserting and fitting the convex portion into the concave groove so as to be able to engaged thereto when the cutting tip is inserted into the tip mounting seat and is taken out of the tip mounting seat, the movement of the cutting tip in other directions other than the inserting and fitting direction is restricted. In this way, since the cutting tip is not shifted within the tip mounting seat or the cutting tip does not drop out from the tip mounting seat even if gravity is applied in the direction where the movement of the cutting tip is restricted, for example, at the time of performing a corner change of the cutting tip or a tip replacement in a state of mounting the cutting tool in a main axis or on a tool post of the machine tool, a removal operation of the cutting tip to the cutting tool becomes easy and therefore hours required for the operation are shortened. 
     It is preferable that in the indexable cutting tool, a size of the cross sectional configuration in the concave groove relative to that of the cross sectional configuration in the convex portion is larger at an outer side end portion of the concave groove positioned at an outer side of the tool body in the cutting tool than at an inner side end portion of the concave groove positioned at an inner side of the tool body in the cutting tool. With this configuration, since it is easier to insert and fit the convex portion into the concave groove at the time of inserting the cutting tip into the tip mounting seat, a cutting tip mounting operation to the cutting tool becomes easy. Also the engagement between the convex portion and the concave groove is not weakened. 
     It is desirable to extend the concave groove in a direction intersecting with a vertical direction, preferably in a direction intersecting at 60 degrees to 90 degrees with a vertical direction. In consequence, the movement of the cutting tip in the vertical direction is restricted when the cutting tip is inserted into the tip mounting seat and is taken out of the tip mounting seat. Thereby, for example, when the cutting tool is mounted on a tool machine such as a vertical milling machine or a vertical machining center with the front end side (tip side) directed downward in the vertical direction, the cutting tip does not drop out from the tip mounting seat to be missed and also a removal operation of the cutting tip to the cutting tool becomes easy and hours required for the operation are shortened. For securely preventing the cutting tip from dropping out from the tip mounting seat, it is preferable that the extending direction of the concave groove intersects at angles of 60 degrees to 90 degrees with the vertical direction. 
     According to the aforementioned temporary coupling mechanism for the cutting tip and the indexable cutting tool equipped with the mechanism, the insert and the removal of the cutting tip into and from the tip mounting seat become easy. In consequence, a removal operation of the cutting tip to the tip mounting seat and the cutting tool becomes easy, and hours required for the operation are shortened. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is perspective view of an indexable end mill to which the present invention is applied; 
         FIG. 2  is a front view of the end mill shown in  FIG. 1  as viewed from a front end side; 
         FIG. 3  is a plan view of the end mill shown in  FIG. 1 ; 
         FIG. 4  is a right side view of the end mill shown in  FIG. 1 ; 
         FIG. 5  is an enlarged cross section taken along line V-V shown in  FIG. 3 ; 
         FIG. 6  is an enlarged view of a VI portion shown in  FIG. 1 ; 
         FIG. 7  is a perspective view of a cutting tip used in the end mill shown in  FIG. 1 ; 
         FIG. 8  is a front view of the cutting tip shown in  FIG. 7 ; 
         FIG. 9  is a plan view of the cutting tip shown in  FIG. 7 ; 
         FIG. 10  is a left side view of the cutting tip shown in  FIG. 7 ; 
         FIG. 11A  is a partial cross sectional side view of an indexable face milling cutter to which the present invention is applied; 
         FIG. 11B  is an enlarged view of an XIB portion in  FIG. 11A ; and 
         FIG. 12  is a partial cross sectional side view of another indexable face milling cutter to which the present invention is applied. 
     
    
    
     DETAILED DESCRIPTION 
     As to an embodiment of the present invention, a temporary coupling mechanism for a cutting tip to which the present invention is applied and an indexable end mill (hereinafter, called an end mill) equipped with the mechanism will be explained with reference to the accompanying drawings.  FIG. 1  is a perspective view showing the end mill as viewed from a front end side.  FIG. 2  is a front view of the end mill shown in  FIG. 1  as viewed from a front end side.  FIG. 3  and  FIG. 4  each are a plan view and a right side view of the end mill shown in  FIG. 1 .  FIG. 5  is an enlarged cross section taken along line V-V shown in  FIG. 3 .  FIG. 6  is an enlarged view of a VI portion shown in  FIG. 1 .  FIG. 7  is a perspective view of an indexable cutting tip (hereinafter, called a cutting tip) used in the end mill shown in  FIG. 1 .  FIG. 8  is a front view of the cutting tip shown in  FIG. 7 .  FIG. 9  and  FIG. 10  each are a plan view and a left side view of the cutting tip shown in  FIG. 7 . 
     As shown in  FIG. 1  to  FIG. 4 , a tool body  1  of the present end mill is formed substantially in a shaft shape and comprises a cutting part  1 A at an axial front end side and a shank portion  1 B at an axial back end side. A tip mounting seat  2  in a concave-groove shape opened to an outer peripheral face and a front end face of the cutting part  1 A is provided in a front end portion of the cutting part  1 A. The tip mounting seat  2  extends slightly inclined to the axial line such that an axial back end portion thereof is positioned backward of a front end portion thereof in a tool rotational direction K (refer to  FIG. 4 ). Cutting tip pockets  4  are formed in the forward side of the tip mounting seat  2  in the tool rotational direction. The tip pocket  4  is formed by cutting away the outer peripheral face of the cutting part  1 A along a direction of extending the tip mounting seat  2 . 
     As shown in  FIG. 7  to  FIG. 10 , the cutting tip  10  has a substantially rectangular plate-shaped tip body in a plan view ( FIG. 9 ). A cutting face  11  is formed on a top face of the cutting tip  10 , a seat face  10   a  is formed on a lower face thereof and flank faces  12   a ,  12   b  and  12   c  are formed on side faces intersecting with the top face and the lower face. An arc-shaped corner cutting edge  13   a  is formed in a corner portion C which is one section of the substantially rectangular top face on which the cutting face  11  is formed. A major cutting edge  13   b  and a minor cutting edge  13   c  are formed respectively on a long side and a short side of the rectangular top face. The long side and the short side respectively extend from the corner cutting edge  13   a . The cutting face  11  is formed in such a manner as to be connected to the ridge line of the major cutting edge  13   b  and recessed in the lower face side to form a curved face. The rake angle of the cutting face  11  is positive, which is defined by a tangential line formed in the curved face at the ridgeline of the major cutting edge  13   b . The corner cutting edge  13   a  and the minor cutting edge  13   c  are formed corresponding to the curved cutting face  11  by curved cutting edges recessed in the lower face side. It is preferable to provide a linear or arc-shaped flat cutting edge  13   d  in a portion of the minor cutting edge  13   c  neighbored to an end portion of the corner cutting edge  13   a  for improving surface roughness of a finish surface. Respective flank faces  12   a ,  12   b  and  12   c  formed in side faces extending respectively from the corner cutting edge  13   a , the major cutting edge  13   b  and the minor cutting edge  13   c  are defined as flank faces each having a positive flank angle inclined inward toward the lower face side. 
     Hereinafter, a major construction of the temporary coupling mechanism for the cutting tip will be explained. 
     As shown in  FIG. 9 , the cutting tip  10  has the substantially rectangular top face. On the top face, another corner portion C′ is positioned at an opposing angle of the corner portion C where the corner cutting edge  13   a  is formed. A long side of the rectangle extends from the another corner portion C′, and concave portions  14  as recessed toward the lower face side are provided in a portion of the top surface extending from the long side. The concave portions  14  are provided at two locations as to have a clearance therebetween along the long side. A bottom face  14   a  of the concave portion  14  is defined as a flat face vertical to a center axis line of a female screw shown in  FIG. 5 . In addition, as apparent from  FIG. 8  to  FIG. 10 , flat faces substantially at right angles to the lower face are formed on side faces respectively extending from the another corner portion C′. The flat faces are defined as restricted faces  15   a  and  15   b  respectively contacting with restricting wall faces  3   b  and  3   c  of the tip mounting seat  2  described later. 
     Further, as shown in  FIG. 7  to  FIG. 10 , a convex portion  16  is provided so as to extend along a short side of the rectangle extending from the other corner portion C′. The convex portion  16  contacts with the short side and rises upward. The convex portion  16  has a semi-circle-shape in cross section and is formed in a hog-backed shape such that the highest position of the convex portion  16  is higher than the top face of the cutting tip  10  in the thickness direction of the cutting tip  10 . 
     On the other hand, as shown in  FIG. 1  to  FIG. 4 , the tip mounting seat  2  provided in the cutting part  1 A is formed in a concave-groove shape to open to the outer peripheral face and the front end face of the cutting part  1 A. A seat face  3   a  is formed on a side wall face directed in a rotational direction K of the tool body  1  to contact with the seat face  10   a  of the cutting tip  10 . The restricting wall faces  3   b  and  3   c  are respectively formed on a bottom face directed to an outer peripheral side and a wall face directed to a front end side to contact with the restricted faces  15   a  and  15   b  of the cutting tip  10 . A clearance T′ between the seat face  3   a  and a side wall face  3   d  opposing it is slightly larger than a thickness T of the cutting tip  10 . When the cutting tip  10  is seated on the seat face  3   a  of the tip mounting seat  2 , a slight gap is generated between the top face and the side wall face  3   d  of the cutting tip  10 . Two female holes  5  are provided on the outer peripheral face of the cutting part  1 A positioned forward of the tip pocket  3  in the tool rotational direction K. Two female holes  5  open to the side wall face  3   d  at positions exposed to the two concave portions  14  provided in the cutting tip  10 . These female holes  5  are provided at two locations so as to be exposed to the concave portions  14  of the cutting tip  10  seated on the tip mounting seat  2 . 
     Further, a concave groove  6  into which the convex portion  16  of the cutting tip  10  can be inserted and fitted (insert-fit) is formed in the intersection portion between the side wall face  3   d  directed to an opposing side to the rotational direction of the tool body  1  and the restricting wall face  3   c  directed to the front end side of the tool body  1 . The concave groove  6  is provided to extend from an opening end of the tip mounting seat  2  over the bottom face in which the restricting wall face  3   b  is formed. In some embodiments, the concave groove and the convex portion have complementary shapes. 
     The mounting and removal method of the cutting tip  10  in the indexable end mill equipped with the temporary coupling mechanism for the cutting tip  10  described above will be hereinafter explained. The insert of the cutting tip  10  into the tip mounting seat  2  is performed while inserting and fitting the convex portion  16  of the cutting tip  10  into the concave groove  6  of the tip mounting seat  2 . In a state where the convex portion  16  is thus being inserted and fitted into the concave groove  6 , the restricted faces  15   a  and  15   b  of the cutting tip  10  contact with the restricting wall faces  3   b  and  3   c  or come close to them having a slight clearance therebetween. Therefore, the cutting tip  10  can be smoothly inserted into or removed from the tip mounting seat  2 . The cutting tip  10  moves in an extending direction of the concave groove  6  and is inserted into the tip mounting seat  2 . The cutting tip  10  thus inserted into the tip mounting seat  2  is fixed in such a manner that screw members  20  such as hexagon socket setscrews (JIS B 1177) are threaded into female screw holes  5  at two locations provided in the cutting part  1 A, and the front end face of the screw member  20  contacts with the bottom face  14   a  of the concave portion  14  in the cutting tip and presses the cutting tip  10  toward the seat face  3   a  of the tip mounting seat. In a case where a central line of each of the female screw hole  5  and the screw member  20  is herein in parallel with a perpendicular line of the seat face  3   a  of the tip mounting seat  2 , the cutting tip  10  is simply pressed toward the seat face  3   a  of the tip mounting seat  2 . As shown in  FIG. 5 , however, in a case where the central line of each of the female screw hole  5  and the screw member  20  is inclined to the perpendicular line in such a manner that as these center lines come closer to the seat face  3   a  of the tip mounting seat  2 , these center lines gradually come closer to the two restricting wall faces  3   b  and  3   c , the cutting tip  10  is pressed against the seat face  3   a  of the tip mounting seat and at the same time is also pressed against the two restricting wall faces  3   b  and  3   c . In reverse, the removal of the cutting tip  10  from the tip mounting seat  2  is performed in such a manner that after the screw member  20  is loosened to leave the front end portion of the screw member  20  away from the bottom face  14   a  of the concave portion in the cutting tip, the cutting tip  10  is moved in the extending direction of the concave groove  6  to be removed from the tip mounting seat  2 . 
     The cutting tip  10  installed in the tool body  1  is arranged such that the cutting face  11  is directed to the forward side in the rotational direction K of the tool body  1  and the corner cutting edge  13   a  protrudes from the outer peripheral face and the front end face of the tool body  1 . The indexable end mill rotated around a center line of the tool body  1  is fed in a direction at right angles to the center line to a workpiece to cut the workpiece with the corner cutting edge  13   a , the major cutting edge  13   b  and the minor cutting edge  13   c , thus machining the workpiece to be in a desired shape. 
     An operational effect of the indexable end mill will be hereinafter explained. 
     In a case of inserting the cutting tip  10  into the tip mounting seat  2  and taking the cutting tip  10  out of the tip mounting seat  2 , since the convex portion  16  of the cutting tip  10  is inserted and fitted into the concave groove  6  of the tip mounting seat  2 , the cutting tip  10  is movable only in the extending direction of the concave groove  6  and is not movable in the other direction. In the indexable end mill, the concave groove  6  extends in a direction substantially at right angles to the center line of the tool body  1  to particularly inhibit the movement of the cutting tip  10  in the center line direction. In consequence, in a case of performing replacement or corner change of the cutting tip  10  in a state of mounting the indexable end mill on a tool machine where a main axis is arranged in a vertical direction, such as a vertical cutting mill or a vertical machining center, the cutting tip  10  inserted into the tip mounting seat  2  does not drop due to an effect of gravity. Further, since it is not necessary to hold the cutting tip  10  by hand for the cutting tip not to drop, the replacement operation of the cutting tip  10  becomes easy and the operation time is shortened. In the indexable end mill where the center line of the tool body is thus made in parallel with the vertical direction, for preventing the cutting tip  10  from dropping from the tip mounting seat  2 , it is preferable that an angle between the extending direction of the concave groove  6  of the tip mounting seat  2  and the direction of the center line of the tool body  1  is in a range of 60 degrees to 90 degrees. 
     In the indexable end mill, since the convex portion  16  of the cutting tip is provided so as to extend along the short side of the top face, when the cutting tip  10  is inserted into the tip mounting seat  2 , the convex portion  16  is engaged to the concave groove  6  of the mounting seat  2  substantially over an entire length in the extending direction of the concave groove  6 , thus, making it possible to prevent the cutting tip  10  from largely moving back and forth within the tip mounting seat  2 . Even if the convex portions  16  of the cutting tip are scattered at two or more locations in the longitudinal direction of the concave groove  6 , the effect similar to the above can be obtained. The convex portion  16  of the cutting tip is not limited thereto, but may be provided at one location so long as it can be inserted and fitted into the concave groove  6 . In this case, if the concave groove  6  of the tip mounting seat  2  is provided in parallel with either one of the restricting wall faces  3   b  and  3   c , the back and forth movement of the cutting tip  10  can be prevented, since the restricting wall faces  3   b  and  3   c  and the restricted faces  15   a  and  15   b  corresponding to them contact with each other or come close as having a slight clearance therebetween at the time of inserting the cutting tip  10  into the tip mounting seat  2 . 
     The center line of each of the female screw hole  5  and the screw member  20  threaded into the female screw  5  is inclined to the perpendicular line of the seat face  3   a  in such a manner that as the center line comes closer to the seat face  3   a  of the tip mounting seat, the center line gradually comes close to the two restricting wall faces  3   b  and  3   c . As a result, the cutting tip  10  is urged and pressed against the two restricting wall faces  3   b  and  3   c  at the time of fastening the screw member  20 . Therefore, even if an operator does not forcibly press the cutting tip  10  against the two restricting wall faces  3   b  and  3   c  by hand, the cutting tip  10  can be securely and stably fixed to the tip mounting seat  2 . 
     It is preferable that the maximum raised height of the convex portion  16  to the top face of the cutting tip  10  is within a range of 0.2 to 2 mm. In a range of less than 0.2 mm, the convex portion  16  of the cutting tip is not engaged to the concave groove  6  of the tip mounting seat  2  or is engaged insufficiently, the cutting tip  10  possibly drops from the tip mounting seat  2 . When the maximum raised height of the convex portion exceeds 2 mm, since it is difficult to mold the convex portion  16  and the concave groove  6  in a cutting tip manufactured by a powder metallurgical method, productivity is possibly degraded. The convex portion  16  and the concave groove  6  serve to prevent the cutting tip  10  from moving in a predetermined direction within the tip mounting seat  2  and do not serve to position the cutting tip  10  in a predetermined position. Therefore, it is not necessary to exactly manage a relative position relation between the convex portion  16  and the concave groove  6 , greatly facilitating the manufacture of the convex portion  16  and the concave groove  6 . 
     It is preferable that when the convex portion  16  is inserted into the concave groove  6 , the cross sectional configuration of the convex portion  16  is made to an analogous configuration smaller than the cross sectional configuration of the concave groove  6  in consideration of secure engagement therebetween. It is preferable that, for making it easy to insert the convex portion  16  into the concave groove  6 , the cross sectional configuration of the opening in the tip mounting seat  2  which is an inlet side of the concave groove  6  is larger than the other cross sectional configuration or the cross sectional configuration of the convex portion  16  at the forward portion in the inserting and fitting direction of the concave groove  6  is smaller than the other cross sectional configuration. 
     In the temporary coupling mechanism for the cutting tip described above and the indexable end mill equipped with the mechanism, the convex portion  16  is provided in the cutting tip  10  and the concave groove  6  is provided in the side wall face  3   d  of the tip mounting seat  2 , but in reverse, the convex portion  16  may be provided in the side wall face  3   d  of the tip mounting seat  2  and the concave groove  6  may be provided in the cutting tip  10 . In addition, the convex portion  16  or the concave groove  6  may be provided in the lower face side of the cutting tip  10  and corresponding thereto, the convex portion  16  or the concave groove  6  may be provided in the seat face  3   a  of the tip mounting seat  2 . 
     The temporary coupling mechanism for the cutting tip according to the present invention and the indexable end mill equipped with the mechanism are not limited to the construction where the tip mounting seat  2  is formed in a concave-groove shape and can be applied to the tip mounting seat  2  comprising a notch step portion.  FIG. 11A ,  FIG. 11B  and  FIG. 12  show an indexable face milling cutter to which another temporary coupling mechanism for a cutting tip is applied. In these figures, components identical to those in the indexable end mill described above are referred to using the same reference numerals and a detail thereof is omitted. 
     The face milling cutter is configured such that plural cutting tips  10  are arranged through support members  30  (sometimes referred to as “cartridges”) along a circumferential direction of the tool body  1  on an outer peripheral face of the front end portion thereof formed substantially in a disc shape. Each cutting tip  10  is seated on the tip mounting seat  2  comprising the notch step portion formed in the front end portion of the wall face in the support member  30  directed forward in the tool rotational direction K. A wedge member  40  is inserted into a wedge member inserting groove provided at the forward side of the seated cutting tip  10  in the tool rotational direction K. By sinking the wedge member  40  inside the tool body  1  (inside the tool body  1  in a radial direction) using the screw member  50 , the cutting tip  10  is fixed so as to be interposed between the pressing face  40   a  of the wedge member  40  and the seat face  3   a  of the tip mounting seat. 
     Hereinafter, a major construction of the temporary coupling mechanism for the cutting tip will be explained. 
     The cutting tip  10  used in the face milling cutter is formed in a plate-like shape of a substantially square as shown in a right lower corner portion in  FIG. 11A , where the cutting face  11  is formed on a top face (face in a near side of a sheet) of the cutting tip  10 , a seat face  10   a  is formed on a lower face (face in a remote side of a sheet) of the cutting tip  10 , and flank faces (refer to  12   b  and  12   c  in  FIG. 7  to  FIG. 10 ) each having a positive flank angle inclined toward the inside are formed in side faces of the cutting tip  10  extending from the top face toward the lower face. Minor cutting edges  13   c  are formed in ridge lines of four corner portions C on the square top face having the cutting face  11  thereon, and major cutting edges  13   c  are formed in four section ridge portions of the square top face. Further, as viewed from a direction opposed to the lower face on which the seat face  10   a  is formed, two concave grooves  6  are formed on the lower face. The concave grooves  6  are arranged to form a crossed shape intersecting in the central portion of the lower face. Each concave groove  6  extends in parallel with the section ridge portion of the square top face and has both end portions opened to the side face of the cutting tip  10  to form a rectangular cross sectional configuration. 
     The tip mounting seat  2  is provided with the seat face  3   a  on which the cutting tip  10  is seated and two wall faces rising up from the seat face  3   a . The two restricting wall faces  3   b  and  3   c  contacting with the side faces of the cutting tip  10  which are the restricted wall faces (refer to  15   a  and  15   b  in  FIG. 9 ) are formed on the two wall faces. Further, as shown in  FIG. 11A , the convex portion  16  projecting from the seat face  3   a  is formed on the seat face  3   a  of the tip mounting seat  2 . As viewed from a direction opposing the seat face  3   a , the convex portion  16  is configured to extend in parallel with the restricting wall face  3   c . The convex portion  16  has a rectangular cross sectional configuration slightly smaller than the concave groove  6 , and is capable of being inserted and fitted into the concave groove  6  of the cutting tip inserted into the tip mounting seat  2 . The cutting tip  10  is fixed by sinking the wedge member  40  inside the tool body  1  (radial inside of the tool body  1 ) in a state of inserting and fitting the convex portion  16  into the concave groove  6  to press the top face of the cutting tip  10  toward the seat face  3   a  of the tip mounting seat  2  with the pressing face  40   a  of the wedge member  40 . 
     In a case of mounting and taking out the cutting tip  10  into and from the face milling cutter, the insert of the cutting tip  10  into the tip mounting seat  2  is performed while inserting and fitting the convex portion  16  provided in the tip mounting seat  2  into the concave groove  6  provided in the cutting tip  10 . The wedge member  40  herein is in a floating state toward the outside of the tool body  1  (radial outside of the tool body  1 ) as having a clearance between the pressing face  40   a  of the wedge member  40  and the top face of the cutting tip  10 . In a state where the convex portion  16  is thus being inserted and fitted into the concave groove  6 , the restricted faces  15   a  and  15   b  of the cutting tip  10  contact with the restricting wall faces  3   b  and  3   c  or come close thereto having a slight clearance therebetween. Therefore, the cutting tip  10  can be smoothly inserted into or taken out of the tip mounting seat  2 . The cutting tip  10  moves in an extending direction of the concave groove  6  to be inserted into the tip mounting seat  2 . The cutting tip  10  thus inserted into the tip mounting seat  2  is fixed by sinking the wedge member  40  inside the tool body  1  (radial inside of the tool body  1 ) to press the top face of the cutting tip  10  toward the seat face  3   a  of the tip mounting seat with the pressing face  40   a  of the wedge member. In reverse, the removal of the cutting tip  10  from the tip mounting seat  2  is performed in such a manner that after the pressing face  40   a  of the wedge member is separated away from the top face of the cutting tip  10  by floating the wedge member  40  outside the tool body  1  (radial outside), the cutting tip  10  is moved in the extending direction of the concave groove  6  to be taken out from the tip mounting seat  2 . 
     In the temporary coupling mechanism for the cutting tip described above, the cross sectional configuration of each of the concave groove  6  formed on the lower face of the cutting tip  10  and the convex portion  16  formed in the tip mounting seat is not limited to the rectangular configuration. As seen in  FIG. 11B , the convex portion  16  and the convex groove  6  can be engaged to each other so as to form a dovetail connection. They may thus be formed in a reversely tapered shape where the cross sectional configuration expands toward the upward side from the seat face  3   a  of the tip mounting seat. In this case, since the floating of the cutting tip  10  in a direction of leaving away from the seat face  3   a  of the tip mounting seat can be restricted, the dropping or the missing of the cutting tip  10  from the tip mounting seat  2  can be remarkably effectively prevented. 
     As exemplified in  FIG. 12 , the convex portion  16  may be provided on the top face of the cutting tip  10  in the face milling cutter. Corresponding to this configuration, the concave groove  6  into which the convex portion  16  is inserted and fitted is formed so as to be recessed from the pressing face  40   a  of the wedge member. The concave groove  6  is provided to extend in parallel with a direction (dashed line L in  FIG. 12 ) where the wedge member  40  floats and sinks as viewed from a direction opposing the seat face  3   a  of the tip mounting seat and is formed such that at least one end portion positioned in a radial outside of the tool body  1  is opened. Thus, the concave groove  6  extends along a direction of movement of the wedge member  40  when the wedge member is tightened or loosened, and opens to a non-pressing top face thereof. The convex portion  16  is formed in a semi sphere so as to be raised from the top face of the cutting tip  10  and is configured such that a position of the convex portion  16  does not change at the time of the corner change of the cutting tip by arranging the convex portion  16  in a substantially central portion of the square face as the top face of the cutting tip  10 . 
     The clamping member of the cutting tip  10  is not limited to the wedge member  40  described above and can be replaced by coupling means in the form of interposing the cutting tip  10  together with the seat face  3   a  of the tip mounting seat. For example, the clamping member may be a pressing member for pressing the top face of the cutting tip  10  toward the seat face  3   a  of the tip mounting seat (not shown). 
     The present invention is not applied so as to be limited to a rotating tool such as the end mill or face milling cutter described above, but can be applied to a cutting tool in the form of removably installing the cutting tip, for example, a turning tool such as a bite tool and a boring tool or a drilling tool such as a drill and a reamer without mentioning.