Symmetrical cutting tool comprising cutting insert and tool holder provided with converging abutment surfaces

Abstract

A cutting tool (1) has a cutting insert (20), a cutting insert (60) and a tool holder (100). The cutting insert has converging peripheral insert abutment sub-surfaces that exhibit mirror symmetry about a second plane of symmetry. The tool holder has a blade pocket with converging pocket abutment walls that exhibit mirror symmetry about a plane of symmetry of the holder. The cutting tool can be assembled and utilized in four different configurations in a turret.

Description

Technical Field

[0001] The subject matter of the present application relates generally to turning cutting tools and, in particular, to a tool holder having a detachable insert that carries a cutting insert in grooving and parting off metalworking. Background Art

[0002] In the field of metal cutting, inserts with converging peripheral surfaces and symmetry about a plane are known. For example, such cutting inserts are disclosed in US 3,551,977 and DE 3,816,931.

[0003] Also known are cutting tools for turning metalworking operations which can be used for left-handed and right-handed cutting operations and for machining of workpieces that rotate about their axis in both directions. Such a tool is disclosed, for example, in US Pat. No. 3,815,454.

[0004] It is an object of the subject matter of the present application to provide a symmetrical cutting tool having four possible assembly configurations for use in various machining operations. Summary of the invention

[0005] According to a first aspect of the subject matter of the present application, a cutting insert is provided, which extends along a central blade axis defining opposite forward blade directions and rearward blade directions; the cutting insert has a first symmetry plane and a second symmetry plane perpendicular to each other, each of which contains the central blade axis; the cutting insert comprises: opposite first and second blade side surfaces, which extend along the first symmetry plane and on opposite sides of the first symmetry plane; a blade peripheral surface, which connects the first and second blade side surfaces; a blade cutting portion, which comprises a first insert seat; and a blade fastening portion, which extends from the blade cutting portion in the rearward blade direction; the blade peripheral surface comprises: opposite top and bottom blade surfaces, which extend along the second symmetry plane and on opposite sides of the first symmetry plane Extending on the opposite side of the second symmetry plane; a forward blade surface facing forward, which extends between the top blade surface and the bottom blade surface; and a rearward blade end, which is opposite to the forward blade surface; at the blade fastening portion: the top blade surface includes a first peripheral blade adjacent sub-surface; the bottom blade surface includes a second peripheral blade adjacent sub-surface; the first blade side surface and the second blade side surface respectively include a first blade side adjacent sub-surface and a second blade side adjacent sub-surface; and the first blade inner hole opens outward to the first blade side adjacent sub-surface and the second blade side adjacent sub-surface; wherein: the first peripheral blade adjacent sub-surface and the second peripheral blade adjacent sub-surface converge at a first cone angle β1 in the rearward blade direction, and present a mirror-symmetric angle with respect to the first symmetry plane and the second symmetry plane.

[0006] According to a second aspect of the subject matter of the present application, a tool holder is provided, which extends along a holder longitudinal axis defining opposite forward and rearward holder directions; the tool holder has a holder symmetry plane containing the holder longitudinal axis; the tool holder includes: opposite upper and lower holder surfaces, which extend along the holder symmetry plane and on opposite sides of the holder symmetry plane; opposite first and second side holder surfaces, which extend along the holder longitudinal axis and connect the upper and lower holder surfaces; a front holder surface, which connects the upper and lower holder surfaces and the first and second side holder surfaces ; and a blade pocket, which is recessed in the first side retainer surface and opens outwardly to the front retainer surface; the blade pocket includes: a pocket base adjacent surface, which is transverse to the retainer symmetry plane; a first retainer inner hole, which opens outwardly to the pocket base adjacent surface; and a pocket peripheral surface, which extends from the pocket base adjacent surface toward the first side retainer surface and includes: a first pocket adjacent wall and a second pocket adjacent wall, which are located on opposite sides of the retainer symmetry plane and converge in the rear retainer direction; wherein: the first pocket adjacent wall and the second pocket adjacent wall present a mirror-symmetric angle with respect to the retainer symmetry plane; and the upper retainer surface and the lower retainer surface present a mirror-symmetric angle with respect to the retainer symmetry plane.

[0007] According to a third aspect of the subject matter of the present application, a cutting tool is provided, which includes: a tool holder according to the second aspect; a fastening member; a cutting blade according to the first aspect; and a cutting insert, which is releasably fixed to a first insert seat of the cutting blade; the cutting blade is releasably fixed to the tool holder by a fastening member that passes through the first blade inner hole and engages the first holder inner hole; wherein: the mirror-symmetrical angles of the cutting blade and the tool holder are configured to facilitate the cutting blade to be fixed to the tool holder in both of the following two configurations, namely: a first configuration, in which the second blade side adjacent sub-surface is adjacent to the pocket base adjacent surface, and the first peripheral blade adjacent sub-surface and the second peripheral blade adjacent sub-surface are adjacent to the first pocket adjacent wall and the second pocket adjacent wall, respectively; and a second configuration, in which the first blade side adjacent sub-surface is adjacent to the pocket base adjacent surface, and the first peripheral blade adjacent sub-surface and the second peripheral blade adjacent sub-surface are adjacent to the second pocket adjacent wall and the first pocket adjacent wall, respectively.

[0008] Any of the above aspects may be advantageous for one or more of the following reasons: a. A cutting insert having symmetry as described above may be used in varying configurations, allowing greater adaptability to the needs of different machining operations.

[0009] b. The cutting insert and / or tool holder is compact, which is particularly beneficial in some separation operations and eg swiss machining.

[0010] c. The cutting insert and / or tool holder is particularly stable (e.g., spaced apart by its inner bore, or relatively short insert cutting portion, or prismatic dovetail arrangement, etc.).

[0011] d. A tool holder as described above can accommodate cutting inserts as described above in different configurations, while the tool holder itself can be used in varying configurations when attached to a turret. This allows the tool holder to have greater adaptability to the needs of different machining operations.

[0012] e. The cutting tool as described above can be placed in the turret in four different configurations, allowing the cutting tool to be used in varying machining operations with different limitations.

[0013] f. Unlike a slideable blade, a single position pocket allows the blade to be removed and quickly replaced (even flipped over).

[0014] It is understood that the above is an overview and that the features described below may be applicable to the subject matter of the present application in any combination, for example, any of the following features may be applicable to a cutting insert and / or a tool holder and / or a cutting tool.

[0015] In the side view of the cutting insert, at the rearward blade end, the first blade abutment subsurface and the second blade abutment subsurface can merge tangentially with the arcuate terminal end surface with the first radius of curvature. Such an exemplary geometry is preferred for shortening the length of the cutting insert while also allowing the first blade inner hole to be placed as far back as possible.

[0016] The cutting portion longitudinal extent Dc measured along the central insert axis at the insert cutting portion and the fastening portion longitudinal extent Df measured along the central insert axis at the insert fastening portion may satisfy the following condition: Dc ≤ Df. Such a condition ensures that the cutting insert is not overextended during machining operations. In other words, reducing the overhang of the cutting insert results in improved stability (less vibration).

[0017] Preferably, only the blade fastening portion contacts the blade cutting portion. Although it is typically preferred that the blade has additional support to the blade cutting portion by a tool holder that contacts the blade cutting portion, in a preferred embodiment, such support is chosen to be abandoned in order to achieve greater versatility of the tool holder.

[0018] The first insert inner hole may include a first inner hole double-ended cone surface that tapers away from the first insert side surface and the second insert side surface toward the first symmetry plane. Preferably, the fastening member that fixes the cutting insert to the tool holder does not protrude beyond the cutting insert. To this end, the illustrated solution is to make the first insert inner hole have a double-ended cone surface geometry.

[0019] At the blade fastening portion, the cutting blade may also include: a second blade inner hole, which is located in front of the first blade inner hole and is open to the first blade side surface and the second blade side surface; and a third blade inner hole, which is located in front of the first blade inner hole and is open to the first blade side surface and the second blade side surface; the first inner hole double-end cone surface, the second inner hole double-end cone surface and the third inner hole double-end cone surface are mirror-symmetric about the first symmetry plane.

[0020] The first peripheral insert abutment sub-surface and the second peripheral insert abutment sub-surface may exhibit mirror symmetry about the first symmetry plane and the second symmetry plane.

[0021] At the insert fastening portion, the cutting insert may exhibit mirror symmetry about the first symmetry plane and the second symmetry plane.

[0022] The first peripheral blade abutment sub-surface may include a first blade prism; the second peripheral blade abutment sub-surface may include a second blade prism; and the first blade prism and the second blade prism are at a mirror-symmetric angle about the first symmetry plane and the second symmetry plane.

[0023] The first insert seat may include an insert support surface extending transversely to the second symmetry plane; and, at the insert fastening portion, the insert peripheral surface may also include a pair of rearwardly facing insert stop surfaces adjacent to the first peripheral insert abutment sub-surface and the second peripheral insert abutment sub-surface. For Y-axis cutting tools, as will be discussed below, such support is particularly advantageous because the direction of the cutting forces during machining operations is now more toward the pair of insert stop surfaces than in an X-axis tool.

[0024] At the blade fastening portion, the blade peripheral surface may also include: a third peripheral blade abutment sub-surface and a fourth peripheral blade abutment sub-surface, which are located on opposite sides of the second symmetry plane and converge at a second taper angle in the rearward blade direction, the first abutment sub-surface and the third abutment sub-surface are on the same side of the second symmetry plane, and the second abutment sub-surface and the fourth abutment sub-surface are on the same side of the second symmetry plane; a first blade transition surface, which is located between the first peripheral blade abutment sub-surface and the third peripheral blade abutment sub-surface; and a second blade transition surface, which is located between the second peripheral blade abutment sub-surface and the fourth peripheral blade abutment sub-surface. A blade embodiment having such a geometry is particularly desirable in cutting operations with limited space, in which the cutting blade is to be made as small as possible. In such a case, the abutment of the cutting blade and the tool holder according to the first aspect may lack stability (assuming that the first taper angle does not change) due to insufficient or almost insufficient overlap between the cutting blade and the tool holder. To remedy this, the cutting insert may be configured as described above, with a greater overlap with the tool holder and thus better abutment (i.e., with a first cone angle and a second cone angle). In the described embodiment, the first cone angle and the second cone angle are preferably identical to each other, but it is also feasible that they may be different from each other.

[0025] In the side view of the cutting blade, at the rearward blade end, the third blade abutment sub-surface and the fourth blade abutment sub-surface can merge with the flat surface facing backward perpendicular to the central blade axis. Relative to the arc-shaped terminal end surface with the first radius of curvature, the geometry presented herein can shorten the length of the cutting blade. In some cutting operations, a shorter cutting blade may be preferred.

[0026] The first cone angle β1 may satisfy the following condition: 10°≤β1≤80°.

[0027] The first cone angle β1 may also satisfy the following condition: 20°≤β1≤60°.

[0028] The first taper angle β1 may also satisfy the following condition: 25°≤β1≤40°. A small first taper angle β1 is less preferred because it may cause the insert to self-lock to the tool holder, while a large first taper angle β1 may provide insufficient support for the cutting insert (e.g., in the direction of the X-axis cutting operation). Therefore, it has been found that the range specified above is the most advantageous, specifically 25°≤β1≤40°.

[0029] With regard to the tool holder, some preferred features are as follows.

[0030] The tool holder may exhibit mirror symmetry about a holder symmetry plane.

[0031] The pocket peripheral surface may also include: a third pocket abutment wall and a fourth pocket abutment wall, which are located on opposite sides of the holder symmetry plane and converge in the rearward holder direction; a first holder transition surface, which is located between the first pocket abutment wall and the third pocket abutment wall; and a second holder transition surface, which is located between the second pocket abutment wall and the fourth pocket abutment wall. In other words, as described above, such a tool holder is complementary to some of the cutting insert embodiments.

[0032] The first insert side surface and the second insert side surface may be flush or recessed relative to the first side retainer surface in a direction perpendicular to the first symmetry plane. This further allows the cutting tool to complete a close shoulder machining operation.

[0033] At the blade fastening portion, the cutting blade may also include: a second blade inner hole, which is located in front of the first blade inner hole and is open to the first blade side surface and the second blade side surface; and a third blade inner hole, which is located in front of the first blade inner hole and is open to the first blade side surface and the second blade side surface; the blade pocket also includes: a second retainer inner hole, which is located in front of the first retainer inner hole; and a third retainer inner hole, which is located in front of the first retainer inner hole; the first blade inner hole, the second blade inner hole and the third blade inner hole are mirror symmetric about the second symmetry plane; and the first retainer inner hole, the second retainer inner hole and the third retainer inner hole are mirror symmetric about the retainer symmetry plane.

[0034] At the blade fastening portion, the blade peripheral surface may also include a pair of rearward-facing blade stop surfaces adjacent to the first peripheral blade adjacent sub-surface and the second peripheral blade adjacent sub-surface; the blade pocket also includes a pair of forward-facing retainer stop surfaces adjacent to the first pocket adjacent wall and the second pocket adjacent wall; and the pair of blade stop surfaces are adjacent to the pair of retainer stop surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to better understand the present application and to show how it may be implemented in practice, reference will now be made to the accompanying drawings, in which:

[0036] Figure 1 is a perspective view of a cutting portion of a cutting tool according to an embodiment of the present invention (it will be understood that the cutting portion will typically have a shank, but as this is a standard component it is not shown or described, and the word "cutting portion" may be omitted hereinafter and only "cutting tool" or "tool holder" may be used, even though it is understood that the shank is implicit);

[0037] Figure 2 yes Figure 1 An exploded perspective view of a cutting tool;

[0038] Figure 3a yes Figure 1 a side view of a first configuration of a cutting tool;

[0039] Figure 3b yes Figure 1 a side view of a second configuration of the cutting tool;

[0040] Figure 3c yes Figure 1 a side view of a third configuration of the cutting tool;

[0041] Figure 3d yes Figure 1 a side view of a fourth configuration of a cutting tool;

[0042] Figure 4 yes Figure 1 A perspective view of a tool holder;

[0043] Figure 5 yes Figure 1 A front view of a tool holder in FIG.

[0044] Figure 6 yes Figure 1 A front view of a tool holder;

[0045] Figure 7 is a perspective view of a cutting insert according to an embodiment of the present invention;

[0046] Figure 8a yes Figure 7 A first side view of a cutting blade;

[0047] Figure 8b yes Figure 7 A rear end view of the cutting blade;

[0048] Figure 8c yes Figure 7 A second side view of the cutting blade;

[0049] Figure 9a is a perspective view of a cutting tool according to another embodiment of the present invention;

[0050] Figure 9b yes Figure 9a A side view of a cutting blade;

[0051] Fig.9c yes Figure 9a A side view of a tool holder;

[0052] Fig.10a is a perspective view of a cutting tool according to another embodiment of the present invention;

[0053] Fig.10b yes Fig.10aa side view of a cutting blade; and

[0054] Fig.10c yes Fig.10a Side view of a tool holder.

[0055] It will be appreciated that, for simplicity and clarity of illustration, the elements shown in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity, or several physical components may be included in one functional block or element. In addition, reference numerals may be repeated in the drawings to indicate corresponding or similar elements where deemed appropriate. DETAILED DESCRIPTION

[0056] In the following description, various aspects of the subject matter of the present application will be described. For the purpose of explanation, specific configurations and details are described in sufficient detail to provide a thorough understanding of the subject matter of the present application. However, it will also be apparent to those skilled in the art that the subject matter of the present application can be practiced without the specific configurations and details set forth herein.

[0057] First note Figures 1 to 3d , in which a cutting tool 1 is shown. The cutting tool 1 comprises a cutting insert 20 releasably fixed to a tool holder 100 and a cutting insert 60 releasably fixed to the cutting insert 20 .

[0058] Further references Figure 7 to Figure 8c The cutting insert 20 extends along a central insert axis L defining opposite forward and rearward insert directions Fb and Rb. A longitudinal first symmetry plane S1 contains the central insert axis L. A lateral second symmetry plane S2 extends perpendicular to the first symmetry plane S1 and contains the central insert axis L as well.

[0059] The cutting insert 20 includes a first blade side surface 22 and a second blade side surface 24 and a blade peripheral surface 30 extending therebetween. The first blade side surface 22 and the second blade side surface 24 extend along a first symmetry plane S1 and on opposite sides of the first symmetry plane S1. To reiterate, the first symmetry plane S1 passes between the first blade side surface 22 and the second blade side surface 24 (except for containing the central blade axis L).

[0060] The blade peripheral surface 30 connects the first blade side surface 22 and the second blade side surface 24 and includes a top blade surface 32 and a bottom blade surface 34 and a forward blade surface 36 located therebetween facing forward. Each of the top blade surface 32, the bottom blade surface 34 and the forward blade surface 36 extends between the first blade side surface 22 and the second blade side surface 24. The top blade surface 32 and the bottom blade surface 34 extend along the second symmetry plane S2 and on opposite sides of the second symmetry plane S2.

[0061] The cutting blade 20 further includes a blade cutting portion 50 and a blade fastening portion 70. The blade cutting portion 50 extends from the forward blade end 40 in the rearward blade direction Rb. The blade fastening portion 70 extends from the blade cutting portion 50 to the rearward blade end 42. The forward blade end 40 delimits the cutting blade 20 in the forward blade direction Fb. The rearward blade end 42 delimits the cutting blade 20 in the rearward blade direction Rb.

[0062] A first insert seat 62 is located in the insert cutting portion 50 at the intersection of the first insert side surface 22, the second insert side surface 24, and the insert peripheral surface 30. The cutting insert 60 is releasably secured in the first insert seat 62. The first insert seat 62 includes an insert support surface 66 that supports the cutting insert 60 and resists the direction of forces (not shown) acting on the cutting insert 60 during machining operations.

[0063] The first insert seat 62 may also include an insert back support surface 68 supporting the cutting insert 60, the insert back support surface 68 being inclined relative to the insert support surface 66 and preferably, but optionally, perpendicular to the insert support surface 66. By definition, the fastening portion 70 is free of an insert seat. The insert support surface 66 and the insert back support surface 68 are preferably, but optionally, on the same side of the second symmetry plane S2.

[0064] According to some embodiments, the first insert seat 62 is located at the intersection of the first blade side surface 22 , the second blade side surface 24 , the forward blade surface 36 , and one of the top blade surface 32 and the bottom blade surface 34 .

[0065] According to some embodiments, the insert support surface 66 extends in the same general direction as the second symmetry plane S2. Figures 1 to 3d and Figure 7 to Figure 8c, the cutting insert 60 is secured in a first insert seat 62 located at the intersection of the first insert side surface 22, the second insert side surface 24, the forward insert surface 36, and the top insert surface 32. The cutting forces are generally directed in a direction from the top insert surface 32 toward the bottom insert surface 34. In the field of grooving and parting metalworking, cutting tools such as those described above are generally referred to as X-axis cutting tools.

[0066] According to some embodiments, the insert support surface 66 extends transversely to the second symmetry plane S2 (so that its imaginary extension would intersect said second symmetry plane S2). Fig.10a and Fig.10b , the cutting insert 60 is secured in a first insert seat 62 located at the intersection of the first insert side surface 22, the second insert side surface 24, the forward insert surface 36, and the top insert surface 32. The cutting forces are generally directed in a direction from the forward insert surface 36 toward the rearward insert end 42. In the field of grooving and parting metalworking, cutting tools such as those described above are generally referred to as Y-axis cutting tools.

[0067] According to some embodiments, for example Fig.10a and Fig.10b As shown in FIG. 1 , the insert cutting portion 50 also includes a second insert seat 64 located at the intersection of the first insert side surface 22 , the second insert side surface 24 , and the insert peripheral surface 30 , as will be discussed in further detail below.

[0068] Further references Figure 7 to Figure 8c , the blade fastening portion 70 includes a first peripheral blade abutment sub-surface 80a, a second peripheral blade abutment sub-surface 80b, and opposite first blade side abutment sub-surfaces 82 and second blade side abutment sub-surfaces 84 respectively located on the first blade side surface 22 and the second blade side surface 24. When the cutting blade 20 is fixed to the tool holder 100, at least one of the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 abuts against the tool holder 100.

[0069] According to some embodiments, for example Figure 7 to Figure 8c, the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 are preferably but optionally flush with the first blade side surface 22 and the second blade side surface 24, respectively (i.e., forming a continuous surface). Alternatively, the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 may each be positioned further away from the first symmetry plane S1 than the first blade side surface 22 and the second blade side surface 24, wherein a step is formed between the surfaces on the same side of the cutting insert 20. In such a case, the step may have a step shape, or may simply be an inclined surface, etc.

[0070] The blade fastening portion 70 also includes a first blade inner hole 72a (in an embodiment with one or more additional blade inner holes located in front of it, the first blade inner hole 72a may also be referred to as a "rearward first blade inner hole"), which opens outwardly to the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84. The first blade inner hole 72a may exhibit mirror symmetry about the second symmetry plane S2. The first blade inner hole 72a may also exhibit mirror symmetry about the first symmetry plane S1.

[0071] The insert cutting portion 50 preferably but optionally has no insert bore, as in all the embodiments shown. It will be appreciated that bores can weaken the structure, so no bores are preferred. Nevertheless, there may be holes, possibly very small holes, in the insert cutting portion for various reasons, such as to release the cutting insert from the insert pocket, which is typical for some insert pocket types.

[0072] The first peripheral blade abutment sub-surface 80a and the second peripheral blade abutment sub-surface 80b are located on the blade peripheral surface 30, and converge in a V-shaped manner on the opposite side of the second symmetry plane S2 in the backward blade direction Rb. The first peripheral blade abutment sub-surface 80a and the second peripheral blade abutment sub-surface 80b present a mirror symmetric angle about the second symmetry plane S2. The first peripheral blade abutment sub-surface 80a and the second peripheral blade abutment sub-surface 80b can also present mirror symmetry about the second symmetry plane S2. The first peripheral blade abutment sub-surface 80a and the second peripheral blade abutment sub-surface 80b can also be inclined relative to the top blade surface 32 and the bottom blade surface 34, respectively.

[0073] Surfaces having mirror-symmetric angles with respect to their position and slope do not necessarily exhibit perfect mirror symmetry due to possible differences in extent (length) etc. relative to the chosen plane of symmetry. However, surfaces referred to as exhibiting "mirror symmetry" and not just mirror-symmetric angles imply that they also exhibit perfect mirror symmetry.

[0074] In addition, at the rearward blade end 42, the first blade abutment sub-surface 80a and the second blade abutment sub-surface 80b preferably but optionally merge tangentially with the non-adjacent arcuate terminal end surface 45 having a first radius of curvature R1. Having such a radius is used to shorten the blade length L1 (compared with the sharp corner) of the cutting blade 20, while also allowing the first blade inner hole 72a to be positioned as far back as possible. Although it is preferred, it will be noted that the center of such a rounded surface may not necessarily coincide with the center of the first blade inner hole 72a.

[0075] like Figure 8c As seen in FIG. 1 , in a side view of the cutting insert 20, the opposing blade abutment sub-surfaces 80a, 80b of the blade fastening portion 70 taper toward the rearward blade end 42 in the rearward blade direction Rb to form a first taper angle β1. In some embodiments, the first taper angle β1 satisfies the following condition: 10°≤β1≤80°. Preferably, the first taper angle β1 satisfies the following condition: 20°≤β1≤60°. Most preferably, the first taper angle β1 satisfies the following condition: 25°≤β1≤40°.

[0076] According to some embodiments, the first blade inner hole 72a preferably but optionally includes a first inner hole double-end cone surface 74a, which tapers toward the first symmetry plane S1 away from the first blade side surface 22 and the second blade side surface 24. The first inner hole double-end cone surface 74a can present mirror symmetry about the first symmetry plane S1. The first inner hole double-end cone surface 74a can also present mirror symmetry about the second symmetry plane S2.

[0077] According to some embodiments, the blade fastening portion 70 preferably but optionally further includes a second blade inner hole 72 b that opens outwardly to the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 .

[0078] The blade fastening portion 70 preferably but optionally further includes a third blade inner hole 72c, which is open outward to the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84. The second blade inner hole 72b and the third blade inner hole 72c can present mirror symmetry about the second symmetry plane S2 on opposite sides of the second symmetry plane S2. The second blade inner hole 72b and the third blade inner hole 72c are preferably located in front of the first blade inner hole 72a.

[0079] According to some embodiments, each of the second blade inner hole 72b and the third blade inner hole 72c preferably but optionally includes a corresponding second inner hole double-end cone surface 74b and a third inner hole double-end cone surface 74c. Each of the second inner hole double-end cone surface 74b and the third inner hole double-end cone surface 74c tapers away from the first blade side surface 22 and the second blade side surface 24 toward the first symmetry plane S1.

[0080] Each of the second inner hole double-end cone surface 74b and the third inner hole double-end cone surface 74c may exhibit mirror symmetry with respect to the first symmetry plane S1. The second inner hole double-end cone surface 74b and the third inner hole double-end cone surface 74c may exhibit mirror symmetry with respect to the second symmetry plane S2.

[0081] The first peripheral insert abutment sub-surface 80a and the second peripheral insert abutment sub-surface 80b present a mirror-symmetric angle with respect to the first symmetry plane S1. The first peripheral insert abutment sub-surface 80a and the second peripheral insert abutment sub-surface 80b may also present a mirror-symmetry with respect to the first symmetry plane S1.

[0082] According to some embodiments, the cutting insert 20 preferably, but optionally, exhibits mirror symmetry about the first symmetry plane S1. At the fastening portion 70, the cutting insert 20 may also exhibit mirror symmetry about the second symmetry plane S2.

[0083] Follow now Figures 4 to 6 , wherein a tool holder 100 is shown. The tool holder 100 extends along a holder longitudinal axis H defining opposite forward holder directions Fh and rearward holder directions Rh.

[0084] like Figure 5 As can be seen in FIG. 1 , the tool holder 100 has a longitudinal first holder plane Sh1, which contains the holder longitudinal axis H. The tool holder 100 is not mirror-symmetrical about the first holder plane Sh1. The tool holder 100 also has a holder symmetry plane Sh2 perpendicular to the first holder plane Sh1, which also contains the holder longitudinal axis H.

[0085] The tool holder 100 includes an upper holder surface 102 and a lower holder surface 104 that are opposite and extend along a holder symmetry plane Sh2 and on opposite sides of the holder symmetry plane Sh2. The tool holder 100 also includes an opposite first side holder surface 106 and a second side holder surface 108 that extend along a holder longitudinal axis H and connect the upper holder surface 102 and the lower holder surface 104. A front holder surface 110 connects and defines the upper holder surface 102 and the lower holder surface 104 and the first side holder surface 106 and the second side holder surface 108.

[0086] According to some embodiments, the upper retainer surface 102 and the lower retainer surface 104 preferably but optionally present mirror-symmetric angles relative to each other about the retainer symmetry plane Sh2. Figure 6As shown in , the mirror symmetry angle between the upper retainer surface 102 and the lower retainer surface 104 about the retainer symmetry plane Sh2 can be zero. In other words, the upper retainer surface 102 and the lower retainer surface 104 can extend parallel to each other and parallel to the retainer symmetry plane Sh2.

[0087] For example, the "mirror symmetry angle" is mentioned because the upper retainer surface 102 and the lower retainer surface 104 can be relatively longer and shorter, or have different distances from the retainer symmetry plane Sh2, but still provide the required function. Of course, it will be understood that the upper retainer surface 102 and the lower retainer surface 104 can preferably have mirror symmetry about the retainer symmetry plane Sh2.

[0088] According to some embodiments, the tool holder 100 preferably exhibits mirror symmetry about the holder symmetry plane Sh2.

[0089] The insert pocket 120 is recessed in the first side retainer surface 106 and opens outwardly to the front retainer surface 110. The insert pocket 120 includes a pocket base abutment surface 122, a first retainer inner hole 124a, and a pocket peripheral surface 128 transverse to the retainer symmetry plane Sh2. The pocket peripheral surface 128 further converges toward the retainer symmetry surface Sh2 in the rearward retainer direction Rh. Figure 5 As seen in FIG. 1 , the pocket base abutment surface 122 is parallel to the first retainer plane Sh1 , or in other words, perpendicular to the retainer symmetry plane Sh2 .

[0090] According to some embodiments, the tool holder 100 includes only one insert pocket 120. In these embodiments, in order to allow the cutting tool 1 to be operated in both left-handed machining operations and right-handed machining operations, the tool holder 100 is rotated 180° around the holder longitudinal axis H. The insert pocket 120 can then be positioned for right-handed machining as well as left-handed machining. This can allow a more compact tool holder 100 than a tool holder having multiple insert pockets.

[0091] The first retainer inner hole 124a opens outwardly to the pocket base abutment surface 122 and extends toward the second side retainer surface 108. Figure 6 As best seen in FIG. 1 , the first retainer inner hole 124a is preferably close to the V-shaped recessed peripheral surface 128 in the rearward retainer direction Rh. In addition, in embodiments having multiple retainer inner holes, it is the inner hole closest to the recessed peripheral surface 128 in the rearward retainer direction Rh.

[0092] According to some embodiments, the blade pocket 120 includes a second retainer inner hole 124b. Preferably, the blade pocket 120 also includes a third retainer inner hole 124c. The second retainer inner hole 124b and the third retainer inner hole 124c open outwardly to the pocket base abutment surface 122 and extend toward the second side retainer surface 108. The second retainer inner hole 124b and the third retainer inner hole 124c are located in front of the first retainer inner hole 124a. Each of the first retainer inner hole 124a, the second retainer inner hole 124b and the third retainer inner hole 124c can be inclined relative to the pocket base abutment surface 122.

[0093] According to some embodiments, the first retainer inner hole 124a, the second retainer inner hole 124b and the third retainer inner hole 124c preferably but optionally present mirror symmetry about the retainer symmetry plane Sh2. That is, the first retainer inner hole 124a can be opened outwardly to the recess base abutment surface 122 in a manner centered about the retainer symmetry plane Sh2, and the second retainer inner hole 124b and the third retainer inner hole 124c can be opened outwardly to the recess base abutment surface 122 and kept equidistant from the retainer symmetry plane Sh2 on opposite sides of the retainer symmetry plane Sh2.

[0094] The pocket perimeter surface 128 is transverse to the pocket base abutment surface 122 and extends therefrom toward the first side retainer surface 106. The pocket perimeter surface 128 includes a first pocket abutment wall 130a and a second pocket abutment wall 130b that converge in the rearward retainer direction Rh from opposite sides of the retainer symmetry plane Sh2. The first pocket abutment wall 130a and the second pocket abutment wall 130b present a mirror-symmetric angle with respect to the retainer symmetry plane Sh2. The first pocket abutment wall 130a and the second pocket abutment wall 130b may also present a mirror-symmetry with respect to the retainer symmetry plane Sh2.

[0095] like Figure 1 and Figure 2 As best seen in FIG. 1 , when the cutting tool 1 is in an assembled state, the cutting insert 20 is releasably retained in the tool holder 100, and the cutting insert 60 is releasably retained in the cutting insert 20. Specifically, the cutting insert 20 is releasably retained in the insert pocket 120 by a securing member 144. The securing member 144 passes through the first insert inner bore 72a and engages with the first holder inner bore 124a.

[0096] The second blade side abutment sub-surface 84 abuts the pocket base abutment surface 122. The first and second peripheral blade abutment sub-surfaces 80a, 80b abut the first and second pocket abutment walls 130a, 130b, respectively.

[0097] According to some embodiments, a plurality of fastening members pass through a plurality of blade inner holes and engage a plurality of retainer inner holes. Specifically, three fastening members 144 may each be positioned through one of the first blade inner hole 72a, the second blade inner hole 72b, and the third blade inner hole 72c, and engage the first retainer inner hole 124a, the second retainer inner hole 124b, and the third retainer inner hole 124c, respectively.

[0098] Alternatively, although the arrangement shown is considered to be optimal, the cutting insert may only have the first insert inner hole 72a and the second insert inner hole 72b, and the tool holder has the first holder inner hole 124a, the second holder inner hole 124b and the third holder inner hole 124c. In such an option, the second holder inner hole 124b and the third holder inner hole 124c present mirror symmetry about the holder symmetry plane Sh2.

[0099] In such a case, when such a cutting insert is secured to such a tool holder, one securing member 144 may be positioned through the first insert bore 72a to engage the first holder bore 124a, and another securing member 144 may be positioned through the second insert bore 72b to engage one of the second holder bore 124b and the third holder bore 124c.

[0100] It will be noted that the opposite is also possible. For the sake of clarity, it is also possible that the tool holder has only the first holder inner hole 124a and the second holder inner hole 124b, while the cutting insert has the first insert inner hole 72a, the second insert inner hole 72b and the third insert inner hole 72c. In such an option, the second insert inner hole 72b and the third insert inner hole 72c present mirror symmetry about the second symmetry plane S2.

[0101] In such a case, when such a cutting insert is secured to such a tool holder, one securing member 144 may be positioned through the first insert bore 72a, thereby engaging the first holder bore 124a, and another securing member 144 may be positioned through one of the second insert bore 72b and the third insert bore 72c, thereby engaging the second holder bore 124b.

[0102] In the two cases outlined above, the cutting tool can still be mounted to the turret in four different configurations, as will be discussed below.

[0103] According to some embodiments, the fastening member 144 is adjacent to the first inner hole double-end cone surface 74a. Preferably, multiple fastening members are adjacent to multiple inner hole double-end cone surfaces. Specifically, the fastening member 144 can be adjacent to the first inner hole double-end cone surface 74a, the second inner hole double-end cone surface 74b and the third inner hole double-end cone surface 74c respectively.

[0104] The tightening member 144 actuates one of the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 to abut against the pocket base abutment surface 122. At the same time, the tightening member 144 abuts against the first inner hole double end cone surface 74a, the second inner hole double end cone surface 74b and the third inner hole double end cone surface 74c. Preferably but optionally, at least one portion of the first inner hole double end cone surface 74a, the second inner hole double end cone surface 74b and the third inner hole double end cone surface 74c located in the forward blade direction Fb abuts against the tightening member 144 in an offset arrangement, which drives the cutting insert 20 backward in the insert pocket 120.

[0105] Due to the shape of the first and second peripheral insert abutment sub-surfaces 80a, 80b and the first and second pocket abutment walls 130a, 130b, rearward movement of the cutting insert 20 brings the paired surfaces into abutment.

[0106] The first inner hole double end cone surface 74a, the second inner hole double end cone surface 74b and the third inner hole double end cone surface 74c also allow the abutment between the fastening member 144 and the cutting insert 20 to be limited to each of the first insert inner hole 72a, the second insert inner hole 72b and the third insert inner hole 72c, respectively, thereby allowing the fastening member 144 to be flush with the first insert side abutment sub-surface 82 or the second insert side abutment sub-surface 84, as discussed below. Alternatively, the fastening member 144 can abut against one of the first insert side abutment sub-surface 82 and the second insert side abutment sub-surface 84.

[0107] like Figure 8a As best seen in FIG. 5 , the cutting portion longitudinal extent Dc and the fastening portion longitudinal extent Df are defined as follows: The cutting portion longitudinal extent Dc is defined along the central blade axis L and is bounded by the blade cutting portion 50. The fastening portion longitudinal extent Df is defined along the central blade axis L and is bounded by the blade fastening portion 70.

[0108] According to some embodiments, the cutting portion longitudinal extent Dc and the fastening portion longitudinal extent Df preferably but optionally satisfy the following condition: Dc ≤ Df.

[0109] The insert cutting portion 50 and the insert fastening portion 70 are functional parts that are obvious to the skilled person. When the cutting insert 20 is fixed to the tool holder 100, they are also easily identifiable.

[0110] In the cutting insert embodiments 20, 20' shown in the drawings, the exemplary boundary B between the insert cutting portion 50 and the insert clamping portion 70 can be considered to be located at the foremost part of the foremost insert bore. In the cutting insert embodiments 20, 20', the foremost insert bore is the second insert bore 72b and the third insert bore 72c. More specifically, the boundary B between the insert cutting portion 50 and the insert clamping portion 70 can be considered to be located at the foremost part of the second bore double-ended taper 74b and / or the third bore double-ended taper 74c.

[0111] As Figure 8a and Figure 9b seen in the insert embodiments of, the cutting inserts 20, 20' have an overall insert length L1 = Dc + Df and an insert height H1. In some embodiments, the insert height H1 and the insert length L1 satisfy the following conditions: H1 < L1. Preferably, L1 < 3H1. More preferably, L1 < 2H1.

[0112] The insert cutting portion 50 can alternatively be defined relative to the tool holder 100. In such a case, the insert cutting portion 50 is the part of the cutting insert 20 that extends in front of the tool holder 100 when mounted to the tool holder 100.

[0113] According to some embodiments, the first insert side abutment sub-surface 82 and the second insert side abutment sub-surface 84 optionally delimit the first insert side surface 22 and the second insert side surface 24. For example, the distance between the first insert side surface 22 and the second insert side surface 24 can each be located closer to the first symmetry plane S1 than the first insert side abutment sub-surface 82 and the second insert side abutment sub-surface 84. Again, the thickness (width) of the cutting insert 20 can be narrower at the first insert side surface 22 and the second insert side surface 24 than at the first insert side abutment sub-surface 82 and the second insert side abutment sub-surface 84.

[0114] This is consistent with the cutting insert 20 for grooving and cutoff operations, where it is preferred to make the insert thinner where the cutting insert 60 is held so that the insert can enter the narrow grooves cut into the workpiece.

[0115] While the illustrated embodiments are preferred (with an insert cutting portion 50 and an insert clamping portion 70 of equal thickness), it should be understood that for structural strength purposes, the insert clamping portion 70 may be designed to be thicker than the insert cutting portion 50.

[0116] In this case, the boundary B between the blade fastening portion 70 and the blade cutting portion 50 is considered to be located at the forwardmost portion of the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84. As such, the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 extend along the central blade axis L at the blade fastening portion 70.

[0117] The cutting portion longitudinal extent Dc is thus defined as from the forward blade end 40 to the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 (and excluding the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84) or restated as boundary B, parallel to the central blade axis L. The fastening portion longitudinal extent Df is thus defined as from the rearward blade end 42 to the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84 (and including the first blade side abutment sub-surface 82 and the second blade side abutment sub-surface 84) or restated as boundary B, parallel to the central blade axis L.

[0118] Special reference Figures 3a to 3d , the assembled cutting tool 1 has four possible configurations. Figure 3a In the first configuration shown in FIG. 8 , the cutting insert 20 is secured in the insert pocket 120 with the second insert side abutment sub-surface 84 abutting the pocket base abutment surface 122 as described above.

[0119] exist Figure 3b In the second configuration shown in , the first blade side abutment sub-surface 82 abuts the pocket base abutment surface 122 .

[0120] exist Figure 3b In the second construction, relative to Figure 3a In the first configuration, the cutting blade 20 and the cutting insert 60 are both rotated 180° about the central blade axis L. In both configurations, the cutting insert 60 secured in the first insert seat 62 can be used for machining operations. To facilitate the use of the cutting insert 60 in both configurations, the blade cutting portion 50 extends forward of the tool holder 100 without abutting against either of the top blade surface 32 and the bottom blade surface 34 with a support member.

[0121] In turning, a workpiece (not shown) rotates about an axis, and a cutting insert resists the rotation of the workpiece. The workpiece can rotate about the axis in two opposite directions. The first configuration and the second configuration allow the workpiece to be machined in two rotational directions.

[0122] exist Figure 3c In the third configuration shown in FIG. , the tool holder 100 is positioned relative to Figure 3a The configuration shown in FIG. 1 is rotated 180°, wherein the first blade side abutment sub-surface 82 abuts the pocket base abutment surface 122 .

[0123] exist Figure 3d In the fourth configuration shown in FIG. , the tool holder 100 is relative to Figure 3b The configuration shown in FIG. 1 is rotated 180°, wherein the second blade side abutment sub-surface 84 abuts the pocket base abutment surface 122 .

[0124] For detailed description, it will be understood that the symmetry of the cutting insert 20 allows it to be mounted in the same tool holder 100 in two orientations. In addition, the symmetry of the tool holder 100 allows it to be mounted in the turret in two orientations. Therefore, the same cutting insert 20 and tool holder 100 allow the four different machining configurations described above.

[0125] The four configurations of the cutting tool 1 mean that the operator can use the same cutting blade 20, cutting insert 60 and tool holder 100 in varying machining operations. This eliminates the need to obtain a specific cutting tool for each cutting operation and eliminates the need to replace the cutting tool used. Instead, the symmetry of the cutting tool 1 of the present invention can be repeatedly used for different turning operations, such as both right-handed machining operations and left-handed machining operations.

[0126] According to some embodiments, when the cutting tool 1 is in an assembled state, the fastening member 144 and the first blade side surface 22 and the second blade side surface 24 are preferably but optionally flush or recessed in a direction perpendicular to the first symmetry plane S1 relative to the first side retainer surface 106. In other words, the first side retainer surface 106 can define the cutting tool 1 in a direction perpendicular to the first symmetry plane S1.

[0127] It is possible that one of the first blade side surface 22 and the second blade side surface 24, or the fastening member 144, or both, protrudes beyond the first side retainer surface 106 in a direction perpendicular to the first plane of symmetry S1. However, it is still preferred that such protrusion is minimal. For example, the fastening member 144 may protrude beyond the first side retainer surface 106 in a direction perpendicular to the first plane of symmetry S1 by 2 mm or less, and preferably 1 mm or less.

[0128] One way to allow the fastening member 144 to be flush or recessed relative to the cutting insert 20 is to use a tapered surface, such as the first inner hole double end cone surface 74a, the second inner hole double end cone surface 74b and the third inner hole double end cone surface 74c. The abutment of the fastening member 144 can then be limited within the first insert inner hole 72a, the second insert inner hole 72b and the third insert inner hole 72c.

[0129] In certain machining operations, it is desirable to have all of the fastening members 144 and cutting inserts 20 flush or recessed in a direction perpendicular to the first symmetry plane S1 relative to the first side retainer surface 106. This may allow the cutting tool 1 to machine a workpiece to the same depth at most points along its axis, regardless of radially extending obstructions.

[0130] According to some embodiments, for example Figure 8b As shown in the figure, the first peripheral blade abutment sub-surface 80a and the second peripheral blade abutment sub-surface 80b of the cutting blade 20 preferably but optionally include a first blade prism 90a and a second blade prism 90b, respectively, and the first blade prism 90a and the second blade prism 90b present a mirror symmetric angle about the second symmetry plane S2. The first blade prism 90a and the second blade prism 90b can also present a mirror symmetry about the second symmetry plane S2.

[0131] Each of the first and second blade prisms 90a, 90b is V-shaped, converging convexly from the first and second blade side surfaces 22, 24. Each of the first and second blade prisms 90a, 90b is adapted to further secure the cutting blade 20 in the blade pocket 120, as will be defined below.

[0132] Specifically, the first peripheral blade abutment sub-surface 80a may include a first V-shaped blade prism 90a that converges in a first direction away from the second symmetry plane S2 and toward the first symmetry plane S1. The second peripheral blade abutment sub-surface 80b may include a second V-shaped blade prism 90b that converges in a second direction away from the second symmetry plane S2 and toward the first symmetry plane S1. Each of the first blade prism 90a and the second blade prism 90b may present a mirror-symmetric angle with respect to the first symmetry plane S1. Each of the first blade prism 90a and the second blade prism 90b may also present a mirror-symmetry with respect to the first symmetry plane S1.

[0133] According to some embodiments, as in Figure 5 and Figure 6 As best seen in FIG. 1 , the first pocket abutment wall 130a and the second pocket abutment wall 130b converge in the rearward retainer direction Rh. Furthermore, the first pocket abutment wall 130a and the second pocket abutment wall 130b may preferably but optionally extend in an outward direction from the pocket base abutment surface 122 and converge toward the retainer symmetry plane Sh2 to produce a dovetail arrangement.

[0134] The inclination of the first and second pocket abutment walls 130a, 130b can accommodate abutment with the first and second blade prisms 90a, 90b. The abutment between the first and second blade prisms 90a, 90b and the first and second pocket abutment walls 130a, 130b will direct the forces generated by engagement (not shown) in a direction perpendicular to the first and second pocket abutment walls 130a, 130b.

[0135] Further references Figures 9a to 9c , shows a cutting tool 1' according to another embodiment of the present invention. The cutting tool 1' comprises a cutting insert 20' and a tool holder 100'. Elements having similar functions will be used herein. Figures 1 to 8c The same numbers are used to indicate the same.

[0136] The blade fastening portion 70 of the cutting blade 20' also includes a first blade transition surface 86a, a second blade transition surface 86b, a third peripheral blade abutment subsurface 80c, and a fourth peripheral blade abutment subsurface 80d. The third peripheral blade abutment subsurface 80c and the fourth peripheral blade abutment subsurface 80d are located behind the first peripheral blade abutment subsurface 80a and the second peripheral blade abutment subsurface 80b.

[0137] The third peripheral blade abutment sub-surface 80c and the fourth peripheral blade abutment sub-surface 80d converge in the rearward blade direction Rb on opposite sides of the second symmetry plane S2. Figure 9b At the rearward insert end 42, the third and fourth insert abutment sub-surfaces 80c, 80d merge with a rearwardly facing flat surface 47 perpendicular to the central insert axis L. This is an alternative option to shorten the insert length L1 of the cutting insert 20'.

[0138] As in the case of the cutting insert 20' Figure 9b As best seen in the side view of , when the first peripheral blade abutment sub-surface 80a and the second peripheral blade abutment sub-surface 80b converge at a first taper angle β1 in the rearward blade direction Rb, the third peripheral blade abutment sub-surface 80c and the fourth peripheral blade abutment sub-surface 80d converge at a second taper angle β2 in the same rearward blade direction Rb. Although it is preferred that the first taper angle β1 and the second taper angle β2 are the same in some embodiments, it is feasible that the first taper angle β1 and the second taper angle β2 may be different from each other.

[0139] The first blade transition surface 86a is located between the first peripheral blade abutment sub-surface 80a and the third peripheral blade abutment sub-surface 80c. Notably, both the first peripheral blade abutment sub-surface 80a and the third peripheral blade abutment sub-surface 80c are on the same side of the second symmetry plane S2.

[0140] The second blade transition surface 86b is located between the second peripheral blade abutment sub-surface 80b and the fourth peripheral blade abutment surface 80d. It is noteworthy that both the second peripheral blade abutment sub-surface 80b and the fourth peripheral blade abutment surface 80d are on the same side of the second symmetry surface S2.

[0141] The third and fourth peripheral blade abutment sub-surfaces 80c and 80d may include third and fourth blade prisms 90c and 90d, respectively.

[0142] The pocket peripheral surface 128 of the tool holder 100' further includes first and second holder transition surfaces 136a, 136b and third and fourth pocket abutting walls 130c, 130d. The third and fourth pocket abutting walls 130c, 130d are located behind the first and second pocket abutting walls 130a, 130b.

[0143] The third pocket abutting wall 130c and the fourth pocket abutting wall 130d converge in the rear holder direction Rh from opposite sides of the holder symmetry plane Sh2.

[0144] According to some embodiments, the third and fourth pocket abutment walls 130c, 130d preferably, but optionally, extend in an outward direction from the pocket base abutment surface 122 and converge toward the holder symmetry plane Sh2 to create a dovetail-like arrangement.

[0145] The first retainer transition surface 136a is located between the first pocket abutting wall 130a and the third pocket abutting wall 130c.

[0146] The second retainer transition surface 136b is located between the second pocket abutting wall 130b and the fourth pocket abutting wall 130d.

[0147] When the cutting tool 1' is in an assembled state, as shown in FIG. Figure 9a As seen in the figure, the cutting insert 20' is releasably fixed to the tool holder 100', as specified above. The first peripheral insert abutment sub-surface 80a and the second peripheral insert abutment sub-surface 80b abut against the first pocket abutment wall 130a and the second pocket abutment wall 130b. The third peripheral insert abutment sub-surface 80c and the fourth peripheral insert abutment sub-surface 80d abut against the third pocket abutment wall 130c and the fourth pocket abutment wall 130d. Although it is counterintuitive to have such a large number of abutment surfaces, it is found that the combination of precision cutting and flexibility of the insert is sufficient to avoid the problem of over-constraint.

[0148] In such an embodiment, Figures 9a to 9c, when attempting to insert the cutting insert 20' from the front retainer surface 110 into the insert pocket 120 along the insert center axis L, the first pocket abutment wall 130a and the second pocket abutment wall 130b abut against the third peripheral insert abutment sub-surface 80c and the fourth peripheral insert abutment sub-surface 80d, thereby interfering with the longitudinal insertion of the cutting insert 20'. To overcome such interference, the cutting insert 20' can instead be inserted into the insert pocket 120 from the first side retainer surface 106 in a direction perpendicular to the first symmetry plane S1.

[0149] As specified above, the engagement between the insert prisms 90a, 90b, 90c, 90d and the pocket abutment walls 130a, 130b, 130c, 130d that converge in an outward direction away from the pocket base abutment surface 122 further supports the cutting insert 20' against the pocket base abutment surface 122. However, the opening of the insert pocket 120 to the first side retainer surface 106 is too narrow to accommodate the direct insertion of the cutting insert 20' having the first insert prism 90a, the second insert prism 90b, the third insert prism 90c and the fourth insert prism 90d in a direction perpendicular to the first symmetry plane S1.

[0150] According to some embodiments, when the cutting tool 1 'is in an assembled state, the first blade transition surface 86a and the second blade transition surface 86b are kept at a distance from the first retainer transition surface 136a and the second retainer transition surface 136b. The blade pocket 120 having a gap that allows limited movement along the central blade axis L can therefore allow the cutting blade 20' to be inserted into the blade pocket 120, as will be explained below.

[0151] The cutting insert 20' is first moved perpendicularly to the first symmetry plane S1, so that one of the first insert side abutment sub-surface 82 and the second insert side abutment sub-surface 84 contacts the pocket base abutment surface 122. At this time, the first insert transition surface 86a and the second insert transition surface 86b are located near the first retainer transition surface 136a and the second retainer transition surface 136b, and possibly abut the first retainer transition surface 136a and the second retainer transition surface 136b.

[0152] Due to the clearance, the opening of the insert pocket 120 to the first side retainer surface 106 can accommodate the insertion of the cutting insert 20' in a direction perpendicular to the first symmetry plane S1. At this stage, the first insert prism 90a, the second insert prism 90b, the third insert prism 90c and the fourth insert prism 90d are spaced apart from the first pocket abutting wall 130a, the second pocket abutting wall 130b, the third pocket abutting wall 130c and the fourth pocket abutting wall 130d.

[0153] Then, the cutting blade 20' moves in the rearward blade direction Rb, so that the first blade transition surface 86a and the second blade transition surface 86b are kept at a distance from the first retainer transition surface 136a and the second retainer transition surface 136b, and the first blade prism 90a, the second blade prism 90b, the third blade prism 90c and the fourth blade prism 90d are adjacent to the first recess adjacent wall 130a, the second recess adjacent wall 130b, the third recess adjacent wall 130c and the fourth recess adjacent wall 130d.

[0154] Reference now Figures 10a to 10c , which shows yet another embodiment of the present invention. A cutting tool 1 "according to another embodiment of the present invention is shown. The cutting tool 1 "includes a cutting insert 20 "and a tool holder 100 ". Elements having similar functions will be used herein. Figures 1 to 9c The same numerical designations are used to indicate the same.

[0155] The cutting insert 20" also includes a second insert seat 64 and a pair of rearward-facing insert stop surfaces 38a, 38b. The second insert seat 64 is located at the intersection of the first insert side surface 22, the second insert side surface 24 and the insert peripheral surface 30. The second insert seat 64 is preferably but optionally located at the intersection of the first insert side surface 22, the second insert side surface 24, the bottom insert surface 34 and the forward insert surface 36.

[0156] In some preferred embodiments, the first insert seat 62 and the second insert seat 64 are mirror-symmetric with respect to the second symmetry plane S2.

[0157] The tool holder 100" also includes a pair of holder stop surfaces 138a, 138b facing forward. When the cutting tool 1" is in an assembled state, the pair of blade stop surfaces 38a, 38b abut against the pair of holder stop surfaces 138a, 138b.

[0158] In some embodiments, Fig.10b As shown in FIG, the rearwardly facing pair of blade stop surfaces 38a, 38b extend perpendicularly to the second symmetry plane S2. The pair of blade stop surfaces 38a, 38b may exhibit mirror symmetry with respect to the first symmetry plane S1 and the second symmetry plane S2.

[0159] The abutment between the pair of insert stop surfaces 38a, 38b and the pair of holder stop surfaces 138a, 138b strengthens the coupling between the cutting insert 20" and the tool holder 100", thereby strengthening the rigidity of the cutting tool 1" as a whole.

[0160] Such stop surfaces are particularly desirable in Y-axis cutting tools. As described above, in a Y-axis cutting tool, the cutting forces are generally directed along the central blade axis L. The more the cutting forces are directed in the forward blade and retainer direction to the rearward blade and retainer direction, the better the support of the blade stop surfaces 38a, 38b and the retainer stop surfaces 138a, 138b against the cutting forces.

[0161] Although the subject matter of the present application has been described with a certain degree of particularity, it will be understood that various changes and modifications can be made without departing from the spirit or scope of the invention as hereinafter claimed.

Claims

1. A cutting insert (20, 20', 20"), the cutting insert (20, 20', 20") extending along a central insert axis (L) defining opposite forward insert directions (Fb) and rearward insert directions (Rb); The cutting insert (20, 20', 20") has a first symmetry plane (S1) and a second symmetry plane (S2) perpendicular to each other, each containing the central insert axis (L); The cutting insert (20, 20', 20") comprises: Opposing first blade side surfaces (22) and second blade side surfaces (24) extending along the first plane of symmetry (S1) and on opposite sides of the first plane of symmetry (S1); a blade peripheral surface (30) connecting the first blade side surface (22) and the second blade side surface (24); a blade cutting portion (50) including a first insert seat (62); as well as a blade securing portion (70) extending from said blade cutting portion (50) in said rearward blade direction (Rb); The blade peripheral surface (30) comprises: opposing top blade surfaces (32) and bottom blade surfaces (34) extending along and on opposite sides of said second plane of symmetry (S2); a forward facing forward blade surface (36) extending between the top blade surface (32) and the bottom blade surface (34); and a rearward blade end (42) opposite the forward blade surface (36); At the blade fastening portion (70): The top blade surface (32) includes a first peripheral blade abutment subsurface (80a); The bottom blade surface (34) includes a second peripheral blade abutment subsurface (80b); The first blade side surface (22) and the second blade side surface (24) include a first blade side abutment sub-surface (82) and a second blade side abutment sub-surface (84), respectively; and The first blade inner hole (72a) opens outwardly to the first blade side abutment subsurface (82) and the second blade side abutment subsurface (84); in: The first peripheral blade abutment sub-surface (80a) and the second peripheral blade abutment sub-surface (80b) converge at a first taper angle β1 in the rearward blade direction (Rb) and present a mirror-symmetric angle with respect to the first symmetry plane (S1) and the second symmetry plane (S2).

2. The cutting insert (20, 20', 20") according to claim 1, wherein: A cutting portion longitudinal extent Dc measured along the central blade axis (L) at the blade cutting portion (50) and a fastening portion longitudinal extent Df measured along the central blade axis (L) at the blade fastening portion (70) satisfy the following condition: Dc≤Df.

3. The cutting insert (20, 20', 20") according to any one of the preceding claims, wherein: The first blade inner hole (72a) comprises a first inner hole double-end cone surface (74a) which tapers away from the first blade side surface (22) and the second blade side surface (24) toward the first symmetry plane (S1).

4. The cutting insert (20, 20', 20") according to any one of the preceding claims, wherein: At the blade fastening portion (70), the cutting blade (20, 20', 20") further comprises: a second blade inner hole (72b) located in front of the first blade inner hole (72a) and opening outwardly to the first blade side surface (22) and the second blade side surface (24); and a third blade inner hole (72c) located in front of the first blade inner hole (72a) and opening outwardly to the first blade side surface (22) and the second blade side surface (24); The first inner hole double-end cone surface (74a), the second inner hole double-end cone surface (74b) and the third inner hole double-end cone surface (74c) present mirror symmetry with respect to the first symmetry plane (S1).

5. The cutting insert (20, 20', 20") according to any one of the preceding claims, wherein: The first peripheral blade abutment sub-surface (80a) and the second peripheral blade abutment sub-surface (80b) exhibit mirror symmetry with respect to the first symmetry plane (S1) and the second symmetry plane (S2).

6. The cutting insert (20, 20', 20") according to claim 5, wherein: At the blade fastening portion (70), the cutting blade (20, 20', 20") exhibits mirror symmetry with respect to the first symmetry plane (S1) and the second symmetry plane (S2).

7. The cutting insert (20, 20', 20") according to any one of the preceding claims, wherein: The first peripheral blade abutment sub-surface (80a) includes a first blade prism (90a); The second peripheral blade abutment sub-surface (80b) includes a second blade prism (90b); and The first blade prism (90a) and the second blade prism (90b) present a mirror-symmetric angle with respect to the first symmetry plane (S1) and the second symmetry plane (S2).

8. The cutting insert (20") according to any one of the preceding claims, wherein: The first insert seat (62) includes an insert support surface (66) extending transversely to the second symmetry plane (S2); and At the blade securing portion (70), the blade peripheral surface (30) further includes a pair of rearwardly facing blade stop surfaces (38a, 38b) adjacent the first peripheral blade abutment sub-surface (80a) and the second peripheral blade abutment sub-surface (80b).

9. The cutting insert (20') according to any one of the preceding claims, wherein: At the blade fastening portion (70), the blade peripheral surface (30) further comprises: a third peripheral blade abutment subsurface (80c) and a fourth peripheral blade abutment subsurface (80d) located on opposite sides of said second symmetry plane (S2) and converging at a second taper angle (β2) in said rearward blade direction (Rb), the first abutment subsurface (80a) and the third abutment subsurface (80c) being on the same side of said second symmetry plane (S2), and the second abutment subsurface (80b) and the fourth abutment subsurface (80d) being on the same side of said second symmetry plane (S2); a first blade transition surface (86a) located between the first peripheral blade abutment sub-surface (80a) and the third peripheral blade abutment sub-surface (80c); and A second blade transition surface (86b) is located between the second peripheral blade abutment sub-surface (80b) and the fourth peripheral blade abutment sub-surface (80d).

10. The cutting insert (20, 20', 20") according to any one of the preceding claims, wherein: The first cone angle β1 satisfies the following condition: 10°≤β1≤80°.

11. The cutting insert (20, 20', 20") according to claim 10, wherein: The first cone angle β1 also satisfies the following condition: 20°≤β1≤60°.

12. The cutting insert (20, 20', 20") according to claim 10, wherein: The first cone angle β1 also satisfies the following condition: 25°≤β1≤40°.

13. A tool holder (100, 100', 100"), the tool holder (100, 100', 100") extending along a holder longitudinal axis (H) defining opposite forward holder directions (Fh) and rearward holder directions (Rh); The tool holder (100, 100', 100") has a holder symmetry plane (Sh2) containing the holder longitudinal axis (H); The tool holder (100, 100', 100") comprises: Opposing upper (102) and lower (104) retainer surfaces extending along and on opposite sides of the retainer symmetry plane (Sh2); Opposing first side retainer surfaces (106) and second side retainer surfaces (108) extending along the retainer longitudinal axis (H) and connecting the upper retainer surface (102) and the lower retainer surface (104); a front retainer surface (110) connecting the upper retainer surface (102) and the lower retainer surface (104) and the first side retainer surface (106) and the second side retainer surface (108); and a blade pocket (120) recessed in the first side retainer surface (106) and opening outwardly to the front retainer surface (110); The blade pocket (120) comprises: a pocket base abutment surface (122) transverse to the retainer symmetry plane (Sh2); a first retainer inner bore (124a) opening outwardly to the pocket base abutment surface (122); and a pocket perimeter surface (128) extending from the pocket base abutment surface (122) toward the first side retainer surface (106) and comprising: a first pocket abutment wall (130a) and a second pocket abutment wall (130b) located on opposite sides of the retainer symmetry plane (Sh2) and converging in the rearward retainer direction (Rh); in The first recess adjacent wall (130a) and the second recess adjacent wall (130b) present a mirror-symmetric angle with respect to the retainer symmetry plane (Sh2); and The upper retainer surface (102) and the lower retainer surface (104) are mirror-symmetrically angled with respect to the retainer symmetry plane (Sh2).

14. The tool holder (100, 100', 100") according to claim 13, wherein: The tool holder (100, 100', 100") exhibits mirror symmetry about the holder symmetry plane (Sh2).

15. The tool holder (100') according to any one of claims 13 and 14, wherein: The recessed peripheral surface (128) further comprises: a third pocket abutment wall (130c) and a fourth pocket abutment wall (130d) located on opposite sides of the retainer symmetry plane (Sh2) and converging in the rearward retainer direction (Rh); a first retainer transition surface (136a) located between the first pocket abutment wall (130a) and the third pocket abutment wall (130c); and A second retainer transition surface (136b) is located between the second pocket abutting wall (130b) and the fourth pocket abutting wall (130d).

16. A cutting tool (1, 1', 1"), the cutting tool (1, 1', 1") comprising: A tool holder (100, 100', 100") according to any one of claims 13 to 15; A fastening member (144); The cutting insert (20, 20', 20") according to any one of claims 1 to 12; as well as a cutting insert (60) releasably secured to a first insert seat (62) of the cutting blade (20, 20', 20"); The cutting insert (20, 20', 20") is releasably secured to the tool holder (100, 100', 100") by the securing member (144) passing through the first insert inner bore (72a) and engaging the first holder inner bore (124a); in: The mirror-symmetric angles of the cutting insert (20, 20', 20") and the tool holder (100, 100', 100") are configured to facilitate the fixing of the cutting insert (20, 20', 20") to the tool holder (100, 100', 100") in both of the following configurations, namely: a first configuration in which the second blade side abutment subsurface (84) abuts the pocket base abutment surface (122), and the first peripheral blade abutment subsurface (80a) and the second peripheral blade abutment subsurface (80b) abut the first pocket abutment wall (130a) and the second pocket abutment wall (130b), respectively; as well as A second construction, in which the first blade side abutment subsurface (82) abuts the pocket base abutment surface (122), and the first peripheral blade abutment subsurface (80a) and the second peripheral blade abutment subsurface (80b) abut the second pocket abutment wall (130b) and the first pocket abutment wall (130a), respectively.

17. The cutting tool (1, 1', 1") according to claim 16, wherein: The first blade side surface (22) and the second blade side surface (24) are flush or recessed relative to the first side retainer surface (106) in a direction perpendicular to the first symmetry plane (S1).

18. The cutting tool (1, 1', 1") according to any one of claims 16 and 17, wherein: At the blade fastening portion (70), the cutting blade (20, 20', 20") further comprises: a second blade inner hole (72b) located in front of the first blade inner hole (72a) and opening outwardly to the first blade side surface (22) and the second blade side surface (24); and a third blade inner hole (72c) located in front of the first blade inner hole (72a) and opening outwardly to the first blade side surface (22) and the second blade side surface (24); The blade pocket (120) further comprises: a second retainer inner hole (124b) located in front of the first retainer inner hole (124a); and A third retainer inner hole (124c) located in front of the first retainer inner hole (124a); The first blade inner hole (72a), the second blade inner hole (72b) and the third blade inner hole (72c) are mirror-symmetric about a second symmetry plane (S2); and The first retainer inner hole (124a), the second retainer inner hole (124b) and the third retainer inner hole (124c) are mirror-symmetric with respect to the retainer symmetry plane (Sh2).

19. The cutting tool (1") according to any one of claims 16 to 18, wherein: At the blade securing portion (70), the blade peripheral surface (30) further includes a pair of rearwardly facing blade stop surfaces (38a, 38b) adjacent the first peripheral blade abutment sub-surface (80a) and the second peripheral blade abutment sub-surface (80b); The blade pocket (120) further includes a pair of forwardly facing retainer stop surfaces (138a, 138b) adjacent the first pocket abutment wall (130a) and the second pocket abutment wall (130b); and The pair of blade stop surfaces (38a, 38b) abut against the pair of retainer stop surfaces (138a, 138b).

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