Cutting tool, cutting tool holder and cutting insert therefor

Abstract

A cutting tool comprising a cutting tool holder and a cutting insert adapted to be mounted thereon. The tool holder comprises an insert seat defined by a base and at least one side wall extending from the base to define an insert seat space adapted to receive therein the insert. The seat comprises a support element extending into the insert seat from the base, and a fastening member engageable with the seat. The fastening member is displaceable with respect thereto between a mounting position adapted to allow the insert to be mounted onto the seat and a securing position adapted for securing the insert within the seat. The insert is formed with a securing cavity and when the insert is mounted onto the tool holder and is in the securing position, a portion of the support element and the fastening member is received within the cavity of the insert.

The invention claimed is: 
     
       1. A cutting tool holder adapted for mounting thereon a cutting insert to form a cutting tool, the cutting tool holder comprising:
 an insert seat space configured for receiving therein the cutting insert, the insert seat space being defined by a base and at least one side wall extending from the base to define an insert seat space adapted for receiving the cutting insert; 
 a support element comprising a shoulder spaced from said at least one side wall, the support element being fixedly and integrally formed with the base and extending therefrom into the insert seat space; 
 a fastening member; and  
 a bore formed in the insert seat open at the base to the insert seat space adjacent the support element and between said side wall and said support element, and configured for receiving a the fastening member for engagement with the insert seat; 
 a support element extending into the insert seat from the base so that the bore is disposed between the side wall and the support element, and being one of the following: integrally formed with the insert seat; or 
 at least during operation, fixedly attached to the insert seat by means other than the fastening member; therewith, 
 wherein when the fastening member being is received within the bore, the fastening member is displaceable with respect to the insert seat base between a mounting position configured for allowing the cutting insert to be mounted onto within the insert seat space and a securing position adapted for securing the cutting insert within the insert seat space; and 
 wherein the fastening member, in the securing position, is configured to engage a sidewall of the support element and apply on the cutting insert a biasing force, directed away from the support element and towards the side wall defining the insert seat space, thereby securing the cutting insert within said insert seat space. 
 
     
     
       2. The cutting tool holder according to  claim 1 , wherein fixed attachment of the support element is achieved via a screwing engagement between the support element and the insert seat. 
     
     
       3. The cutting tool holder according to  claim 1 , wherein the cutting tool is adapted to rotate in a first direction about a central axis thereof, and the support element is formed with a first side wall generally perpendicular to the base and facing in the first direction, and a second side wall extending from the first wall in a direction opposite the first direction, at an acute angle θ to the first wall, both the first side wall and the second side wall being adapted for simultaneous engagement with the cutting insert. 
     
     
       4. The cutting tool holder according to  claim 3 , wherein the second side wall is formed with a recess adapted to receive a corresponding portion of the cutting insert when the latter is mounted onto the insert seat space. 
     
     
       5. The cutting tool holder according to  claim 1 , wherein, in both the mounting position and the securing position, the fastening member remains in engagement with the insert seat. 
     
     
       6. The cutting tool holder according to claim  5  1, wherein in the mounting position the fastening member protrudes to a first extent into the insert seat space, and in the securing position, the fastening member protrudes to a second extent into the insert seat space, greater than the first extent. 
     
     
       7. The cutting tool holder according to claim  5  1, wherein the fastening member is in the form of comprises a securing pin adapted to be received within a corresponding said bore of the insert seat. 
     
     
       8. The cutting tool holder according to  claim 7 , wherein the securing pin is spring biased into the securing position. 
     
     
       9. A cutting insert configured for mounting onto a cutting tool holder to form the cutting tool, the cutting tool holder including comprising: 
 an insert seat space configured for receiving therein the cutting insert, the insert seat space being defined by a base and at least one side wall extending from the base to define an insert seat space adapted for receiving the cutting insert; 
 a support element fixedly and integrally formed with the base and extending therefrom into the insert seat space; 
 a fastening member; and  
 a bore formed in the insert seat configured for receiving a fastening member for engagement with the insert seat; a support element extending into the insert seat from the base so that the bore is disposed between the side wall and the support element, and being one of the following: integrally formed with said insert seat; or at least during operation, fixedly attached to the insert seat by means other than the fastening member  open at the base to the insert seat space adjacent the support element and between said side wall and said support element, and configured for receiving the fastening member for engagement therewith, the bore being; 
 and the fastening member, when received within the bore, being displaceable with respect to the insert seat base between a mounting position configured for allowing the cutting insert to be mounted onto within the insert seat space and a securing position adapted for securing the cutting insert within the insert seat, space; 
 the fastening member, in the securing position, being configured to engage a sidewall of the support element and apply on the cutting insert a biasing force, directed away from the support element and towards the side wall defining the insert seat space, thereby securing the cutting insert within said insert seat space;  
 the cutting insert comprising:
 a top face; 
 a bottom face; and 
 a cavity extending between the top face and the bottom face, the cavity taking up no less that than 15% of the overall volume of the cutting insert, the cavity defining a central axis extending between the top face and the bottom face through the center of an inscribing circle of the cavity, located on a plane substantially perpendicular to the axis, the cavity being formed with an inner surface having a first securing portion with a first geometric shape configured for engagement with the support element, and a second securing portion located at an opposite side of the cavity with respect to the central axis, and having a second geometric shape configured for engagement with the fastening member, both the first and the second securing portion being configured for simultaneously engaging the respective support element and fastening member in the same mounting position. 
 
 
     
     
       10. The cutting insert according to  claim 9 , wherein the first securing portion is closer to one of the top face and the bottom face, and the second securing portion is closer to the other of the top face and the bottom face. 
     
     
       11. The cutting insert according to  claim 9 , wherein the first securing portion is in the form of an arced surface and the second securing portion is substantially planar. 
     
     
       12. The cutting insert according to  claim 9 , wherein both the first securing portion and the second securing portion are in the form of arced surfaces. 
     
     
       13. The cutting insert according to  claim 9 , wherein the cutting insert is reversible, so that the inner cavity comprises comprising:
 a first-side pair of securing portions: 
 a first securing portion oriented closer to the top face; and 
 a second securing portion oriented closer to the bottom face; and 
 at least a second-side pair of securing portions: 
 a first securing portion oriented closer to the bottom face; and 
 a second securing portion oriented closer to the top face. 
 
     
     
       14. The cutting insert according to  claim 9 , wherein the cutting insert is indexible, so that the inner cavity comprises comprising a first pair of securing portions and a second pair of securing portions, each pair comprising:
 a first securing portion oriented closer to the top face; and 
 a second securing portion oriented closer to the bottom face. 
 
     
     
       15. The cutting insert according to  claim 9 , wherein the inner surface of the cavity is further formed with a first inner wall and a second inner wall forming therebetween an acute angle θ, both the first side wall and the second side wall being adapted for simultaneous engagement with the support element. 
     
     
       16. A cutting tool comprising the cutting tool holder of  claim 1 , wherein, at least during operation, the cutting insert is mounted onto the cutting tool holder and secured therein so that the cavity of the cutting insert receives therein at least a portion of both the support element and the fastening element. 
     
     
       17. The cutting tool according to  claim 16 , wherein the cutting tool is adapted to revolve about a central axis thereof in a first direction, and wherein when the cutting insert is mounted onto the cutting tool holder the fastening member is adapted to apply a force F 1  on the cutting insert in a direction generally along the central axis, the force F 1  pushing the cutting insert against the support element which is thereby adapted to apply a force F 2  on the cutting insert in a direction generally perpendicular to the central axis, the resultant force F T  of the two forces F 1  and F 2  being in a direction transverse to the central axis and opposite the first direction. 
     
     
       18. The cutting tool according to  claim 16 , wherein the cutting tool is formed with two or more cutting portions, each cutting portion comprising two or more of the cutting inserts, the cutting edges of which form a continuous cutting edge in each cutting portion, wherein the spatial arrangement of the cutting inserts of the same cutting portion varies from one cutting portion to another. 
     
     
       19. The cutting tool according to  claim 18 , wherein the cutting inserts in each cutting portion are shifted at a distance d with respect to one another, and wherein the shift d varies from one cutting portion to another. 
     
     
       20. The cutting tool holder according to  claim 1 , wherein the support element is formed with an undercut surface extending, at least during operation, at an acute angle to the base and away from the side wall. 
     
     
       21. The cutting insert according to  claim 9 , wherein the cavity takes up no less than 30% of the overall volume of the cutting insert. 
     
     
       22. The cutting insert according to  claim 9 , wherein, in each cross-section of the cutting insert taken along a plane generally parallel to the top face or bottom face, a cross-sectional area of the cavity constitutes no less that than 15% of the entire cross-sectional area of the cutting insert. 
     
     
       23. The cutting tool holder according to  claim 22 , wherein the cross-sectional area of the cavity constitutes no less than 30% of the entire cross-sectional area of the cutting insert. 
     
     
       24. The cutting tool holder according to claim 1, wherein, when in the securing position, said fastening member engages with said support element and said cutting insert. 
     
     
       25. The cutting insert according to claim 9, wherein the cavity takes up no less than 15% of the overall volume of the cutting insert.