# US 11,110,521 B2 · Rotary cutting head having a rigid mounting protuberance and rotary cutting tool

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- Number: US 11,110,521 B2
- Document ID: US11110521B2
- Status: Granted
- Kind: B2
- Application number: 16/261,621
- Filed: 2019-01-30
- Published: 2019-09-12
- Granted: 2021-09-07
- Earliest claimed: 2018-03-07
- Assignees: Iscar, Ltd.
- Applicants: Iscar, Ltd.
- Inventors: Gil Hecht
- Web page: https://patentgrep.com/patent/US11110521B2

## CPC

- B23B 51/0003: {with exchangeable heads or inserts}
- B23B 51/02: Twist drills
- B23B 2251/02: Connections between shanks and removable cutting heads
- B23B 2251/202: Three cutting edges
- B23B: TURNING; BORING (arrangements for copying or controlling B23Q)

## Abstract

A cutting head rotatable about a first axis, has a cap portion and a rigid mounting protuberance joined thereto. The cap portion has a plurality of cutting portions circumferentially alternating with a plurality of head chip flutes, and a head base surface facing in an axial rearward direction. The mounting protuberance exhibits rotational symmetry about the first axis, extends axially rearwardly from the head base surface, and has a plurality of circumferentially spaced apart convex clamping surfaces. The plurality of cutting portions define a cutting diameter, the plurality of head chip flutes are inscribed by an imaginary first circle having a first diameter, and the plurality of clamping surfaces are circumscribed by an imaginary second circle having a second diameter. The first diameter is greater than the second diameter, and the second diameter is less than forty percent of the cutting diameter.

## Claims

### Claim 1

A cutting head (20, 120) rotatable about a first axis (A1) in a first direction of rotation (R1), and comprising:
a cap portion (22) having N cutting portions (26) circumferentially alternating with N head chip flutes (28), and a head base surface (30) facing in an axial rearward direction (DR);
wherein each cutting portion (26) comprises a cutting edge (34) formed at the intersection of an axially forward facing leading surface (32) and a circumferentially adjacent and rotationally forward head chip flute (28), the cutting edge (34) extending in a direction transverse to the first axis (A1); and
a rigid mounting protuberance (24) devoid of resiliently displaceable elements joined to the cap portion (22) and extending axially rearwardly from the head base surface (30), the mounting protuberance (24) exhibiting N-fold rotational symmetry about the first axis (A1), and having N circumferentially spaced apart convex clamping surfaces (38), each clamping surface (38) bisected by a radial clamping bisector plane (PB) containing the first axis (A1),
wherein:
N is an integer number greater than 1,
the N cutting portions (26) define a cutting diameter (DC) corresponding to a cutting circle (CC),
the N clamping surfaces (38) is equal in number to the N cutting portions (26),
in a cross-section taken in a first plane (P1) perpendicular to the first axis (A1) and intersecting the cap portion (22), the N head chip flutes (28) are inscribed by an imaginary first circle (C1) having a first diameter (D1) at N radially innermost head flute points (NH), and
in a cross-section taken in a second plane (P2) perpendicular to the first axis (A1) and intersecting the mounting protuberance (24), the N clamping surfaces (38) are circumscribed by an imaginary second circle (C2) having a second diameter (D2),
and wherein:
the first diameter (D1) is greater than the second diameter (D2), and
the second diameter (D2) is less than forty percent of the cutting diameter (DC).

### Claim 2 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein the second diameter (D2) is less than thirty percent of the cutting diameter (DC).

### Claim 3 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein:
each head flute point (NH) is contained in a radial flute plane (PF) containing the first axis (A1), each radial flute plane (PF) forms a first angle (al) with a circumferentially adjacent radial clamping bisector plane (PB), and
the first angle (al) is less than thirty-five degrees.

### Claim 4 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein in the cross-section taken in the second plane (P2):
the N clamping surfaces (38) form N spaced apart clamping arcs (42) coincident with the imaginary second circle (C2).

### Claim 5 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein N=3.

### Claim 6 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein the mounting protuberance (24) is entirely surrounded by the head base surface (30).

### Claim 7 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein:
the mounting protuberance (24) has N joining surfaces (40) circumferentially alternating with the N clamping surfaces (38), and
each joining surface (40) intersects two circumferentially adjacent clamping surfaces (38).

### Claim 8 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein:
in a cross-section taken in a third plane (P3) perpendicular to the first axis (A1) and intersecting the mounting protuberance (24), the mounting protuberance (24) is circumscribed by an imaginary third circle (C3) having a third diameter (D3) greater than the second diameter (D2), and
the second plane (P2) is located between the first and third planes (P1, P3).

### Claim 9 (depends on 8)

The cutting head (120) according to claim 8, wherein:
the third plane (P3) intersects the N clamping surfaces (38), and
each clamping surface (38) is partially conical shaped.

### Claim 10 (depends on 8)

The cutting head (20) according to claim 8, wherein:
the third plane (P3) does not intersect the N clamping surfaces (38), and
each clamping surface (38) is partially cylindrical shaped.

### Claim 11 (depends on 8)

The cutting head (20) according to claim 8, wherein:
the third plane (P3) intersects N circumferentially spaced apart axial stopper portions (44), and
the imaginary third circle (C3) circumscribes the N axial stopper portions (44).

### Claim 12 (depends on 11)

The cutting head (20) according to claim 11, wherein:
each radial clamping bisector plane (PB) intersects one of the axial stopper portions (44).

### Claim 13 (depends on 11)

The cutting head (20) according to claim 11, wherein:
each axial stopper portion (44) has a stopper surface (48) facing axially forward.

### Claim 14 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein:
a head flute depth (HD) is defined as the radial distance between the head flute points (NH) and the cutting circle (CC); and
the head flute depth (HD) is at least 60% of one-half the cutting diameter (DC).

### Claim 15 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein the N head chip flutes (28) intersect the head base surface (30).

### Claim 16 (depends on 1)

The cutting head (20, 120) according to claim 1, wherein:
N is exactly 3;
the cap portion (22) has exactly three cutting portions (26) and exactly three head chip flutes (28) and
the mounting protuberance (24) has exactly three-fold rotational symmetry and exactly three clamping surfaces (38).

### Claim 17 (depends on 1)

The cutting head (20, 120) according to claim 1, configured as a drill head for use in drilling operations.

### Claim 18

A rotary cutting tool (52, 152) comprising:
a tool shank (54, 154) extending along a second axis (A2) and having a head receiving pocket (56) formed at a forward end thereof, the head receiving pocket (56) comprising a shank support surface (60) transverse to the second axis (A2) and a central recess (62) formed in the shank support surface (60), wherein:
the central recess (62) has N circumferentially spaced apart abutment portions (72),
each abutment portion (72) has a radially inward facing abutment surface (74), and
N is an integer greater than 1; and
a cutting head (20, 120) releasably secured to the head receiving pocket (56), the cutting head being rotatable about a first axis (A1) in a first direction of rotation (R1), and comprising:
a cap portion (22) having N cutting portions (26) circumferentially alternating with N head chip flutes (28), and a head base surface (30) facing in an axial rearward direction (DR);
and
a rigid mounting protuberance (24) joined to the cap portion (22) and extending axially rearwardly from the head base surface (30), the mounting protuberance (24) exhibiting N-fold rotational symmetry about the first axis (A1), and having N circumferentially spaced apart convex clamping surfaces (38), each clamping surface (38) bisected by a radial clamping bisector plane (PB) containing the first axis (A1),
wherein:
the N cutting portions (26) define a cutting diameter (DC) corresponding to a cutting circle (CC),
the N clamping surfaces (38) is equal in number to the N cutting portions (26),
in a cross-section taken in a first plane (P1) perpendicular to the first axis (A1) and intersecting the cap portion (22), the N head chip flutes (28) are inscribed by an imaginary first circle (C1) having a first diameter (D1) at N radially innermost head flute points (NH), and
in a cross-section taken in a second plane (P2) perpendicular to the first axis (A1) and intersecting the mounting protuberance (24), the N clamping surfaces (38) are circumscribed by an imaginary second circle (C2) having a second diameter (D2),
and wherein:
the first diameter (D1) is greater than the second diameter (D2), and
the second diameter (D2) is less than forty percent of the cutting diameter (DC);
wherein in an assembled position:
the head base surface (30) contacts the shank support surface (60) or a plurality of shoulder surfaces (82) offset therefrom,
the second axis (A2) is coincident with the first axis (A1), and
the mounting protuberance (24) is clampingly retained in the central recess (62), with the N clamping surfaces (38) make clamping contact with the N abutment surfaces (74), and
apart from the N clamping surfaces (38) making clamping contact with abutment surfaces (74), no other portion of the mounting protuberance (20) contacts the central recess (62).

### Claim 19 (depends on 18)

The rotary cutting tool (52, 152) according to claim 18, wherein:
the N abutment portions (72) are resiliently displaceable.

### Claim 20 (depends on 18)

The rotary cutting tool (52, 152) according to claim 18, wherein:
The N abutment portions (72) circumferentially alternate with N intermediate portions (76), and
each intermediate portion (76) has an intermediate surface (78) intersecting two circumferentially adjacent abutment surfaces (74).

### Claim 21 (depends on 18)

The rotary cutting tool (52) according to claim 18, wherein:
the clamping surface (38) is partially cylindrically shaped; and
in a cross-section taken in one of the radial clamping bisector planes (PB):
the clamping surface (38) extends parallel to the first axis (A1), and
the associated abutment surface (74) is coincident therewith.

### Claim 22 (depends on 18)

The rotary cutting tool (152) according to claim 18, wherein:
the clamping surface (38) is partially conically shaped; and
in a cross-section taken in one of the radial clamping bisector planes (PB):
the clamping surface (38) diverges away from the first axis (A1) as it extends axially rearwardly, and
the associated abutment surface (74) is coincident therewith.

### Claim 23 (depends on 18)

The rotary cutting tool (52, 152) according to claim 18, wherein:
N circumferentially spaced apart shank chip flutes (64) extend from the shank's forward end (58) along the second axis (A2),
in a cross-section taken in a fourth plane (P4) perpendicular to the first axis (A1) and intersecting the central recess (62), the N shank chip flutes (64) are inscribed by an imaginary fourth circle (C4) having a fourth diameter (D4) at N radially innermost shank flute points (NS), and
the fourth diameter (D4) is between ninety percent and one hundred and ten percent of the first diameter (D1).

### Claim 24 (depends on 23)

The rotary cutting tool (52, 152) according to claim 23, wherein:
the N head chip flutes (26) are corresponding extensions of the N shank chip flutes (64).

### Claim 25 (depends on 23)

The rotary cutting tool (52, 152) according to claim 23, wherein:
a tool flute depth (TD) is defined as the radial distance between the shank flute points (NS) and the cutting circle (CC); and
the tool flute depth (TD) is at least 60% of one-half the cutting diameter (DC).

### Claim 26

A cutting head (20, 120) rotatable about a first axis (A1) in a first direction of rotation (R1), and comprising:
a cap portion (22) having N cutting portions (26) circumferentially alternating with N head chip flutes (28), a head base surface (30) facing in an axial rearward direction (DR), and the N head chip flutes (28) intersecting the head base surface (30); and
a rigid mounting protuberance (24) joined to the cap portion (22) and extending axially rearwardly from the head base surface (30), the mounting protuberance (24) exhibiting N-fold rotational symmetry about the first axis (A1), and having N circumferentially spaced apart convex clamping surfaces (38) and N joining surfaces (40) circumferentially alternating with the N clamping surfaces (38), each clamping surface (38) bisected by a radial clamping bisector plane (PB) containing the first axis (A1), and each joining surface (40) intersecting two circumferentially adjacent clamping surfaces (38),
wherein:
N is an integer number greater than 1,
the N cutting portions (26) define a cutting diameter (DC) corresponding to a cutting circle (CC),
the N clamping surfaces (38) is equal in number to the N cutting portions (26),
each cutting portion (26) has a single cutting edge (34) associated therewith, such that the cutting head has a total of N cutting edges, a total of N cutting portions and a total of N clamping surfaces;
in a cross-section taken in a first plane (P1) perpendicular to the first axis (A1) and intersecting the cap portion (22), the N head chip flutes (28) are inscribed by an imaginary first circle (C1) having a first diameter (D1) at N radially innermost head flute points (NH), and
in a cross-section taken in a second plane (P2) perpendicular to the first axis (A1) and intersecting the mounting protuberance (24), the N clamping surfaces (38) are circumscribed by an imaginary second circle (C2) having a second diameter (D2),
and wherein:
the first diameter (D1) is greater than the second diameter (D2), and
the second diameter (D2) is less than forty percent of the cutting diameter (DC).

### Claim 27 (depends on 26)

The cutting head (20, 120) according to claim 26, wherein the mounting protuberance (24) is devoid of resiliently displaceable elements.

### Claim 28 (depends on 26)

The cutting head (20, 120) according to claim 26, wherein the cap portion (22) and the mounting protuberance (24) both exhibit N-fold rotational symmetry about the first axis (A1).