Patent Application
20220347769
The subject matter of the present application relates to rotary slot cutting tools having a slotting tool body with a disc-like cutter portion having a plurality of circumferentially disposed insert receiving pockets, for releasably retaining a cutting insert therein, in general, and to such slotting tool bodies where the insert receiving pocket resiliently clamps the cutting insert therein, in particular.
Rotary slot cutting tools can have a slotting tool body that has a disc-like cutter portion and a shank portion that extends rearwardly from the disc-like cutter portion. The disc-like cutter portion can be provided with a plurality of circumferentially disposed insert, receiving pockets for retaining a cutting insert therein. The cutting insert can be retained in the insert receiving pocket by a resilient clamping member. An example of such a rotary cutting tool is disclosed in, for example, US 2019/0160555 A1, disclosing a slotting tool body which includes a disc-like cutter portion and a shank portion projecting rearwardly therefrom. The cutter portion includes a plurality of resilient clamping portions having a peripherally disposed insert receiving slot. The disc-like cutter portion has a certain flexibility that decreases with each sequential insertion of cutting inserts into respective insert, receiving slots. In particular in cutting tools having a small diameter, said flexibility can be reduced to such an extent that the resilient member(s) cannot be displaced sufficiently to insert the last cutting insert(s).
In accordance with a first aspect of the subject matter of the present application there is provided a slotting tool body, having a body central axis that defines opposite forward and rearward directions and about which the slotting tool body is rotatable in a rotational direction, the slotting tool body comprising:
a disc-like cutter portion comprising:
a shank portion projecting rearwardly from the rearward cutter portion side surface, the shank portion comprising a shank peripheral surface which extends circumferentially about the body central axis; wherein:
In accordance with a second aspect of the subject matter of the present application there is provided a rotary slot cutting tool comprising:
a slotting tool body of the type described above; and
a cutting insert, releasably and resiliently clamped in each of the insert receiving slots by one of the resilient clamping members.
It is understood that the above-said is a summary, and that features described hereinafter may be applicable in any combination to the subject matter of the present application, for example, any of the following features may be applicable to the slotting tool body and the rotary slot cutting tool:
The cutter portion can be divided into a number N of cutter sub-portions. In a median cutter radial plane through both the flexibility recess and the cutter portion peripheral surface, the cutter sub-portions can be spaced apart from each other.
The flexibility recess can exhibit N-fold rotational symmetry about the body central axis.
The flexibility recess can extend in the rearward direction, past the rearward cutter portion side surfaces and into the shank portion.
The flexibility recess can be intersected by the body central axis.
The flexibility recess can transition into each insert receiving slot at a respective narrowing neck portion.
The flexibility recess can be blind, and open out only to the forward cutter portion side surface.
Each insert receiving slot can be defined by an elongated slot peripheral surface having ends that extend to the cutter portion peripheral surface. The flexibility recess can comprise a recess base surface connecting the insert receiving slots, and a number N of recess peripheral wall surfaces, each of which extends from the recess base surface to the forward cutter portion side surface between the slot peripheral surfaces of two circumferentially adjacent insert receiving slots.
The recess base surface can be oriented perpendicular to the body central axis. The recess peripheral wall surfaces can be oriented parallel to the body central axis.
The recess base surface can intersect with each of the recess peripheral wall surfaces at an intersection which forms a fillet.
The slotting tool body can further comprise an annular groove formed at an intersection of the rearward cutter portion side surface and the shank peripheral surface.
The cutter portion and the shank portion can be integrally formed so that the slotting tool body has a unitary, one-piece construction.
For any given clamping portion, the resilient clamping member can be arranged ahead of the lower jaw member in the rotational direction.
The shank portion can comprise a number N of angularly spaced apart forward shank recesses recessed in, and opening out to, the shank peripheral surface adjacent to the cutter portion. A radially inward portion of each insert receiving slot, can merge on one side thereof with a respective forward shank recess.
The resilient clamping member of each clamping portion can be axially adjacent a respective forward shank recess.
The shank portion can further comprise a number N of peripherally disposed angularly spaced apart non-recessed forward shank portions which can circumferentially alternate with the forward shank recesses and can be axially adjacent the cutter portion.
In a direction along the body central axis, an imaginary radius line extending between the body central axis and the shank peripheral surface can define a shank portion radius of an imaginary shank portion circle that is centered at the body central axis and has a shank portion diameter. The cutter portion can define an imaginary circumscribed cutter portion circle that is centered at the body central axis and that has a cutter portion diameter.
In a direction along the body central axis, the imaginary shank portion circle can intersect all the insert receiving slots.
Each insert receiving slot can be defined by an elongated slot peripheral surface comprising a slot lower jaw abutment surface located on the lower jaw member. In a direction along the body central axis, the imaginary shank portion circle can intersect the slot lower jaw abutment surface.
The slot peripheral surface can further comprise a slot clamping member abutment surface located on the resilient clamping member. In a direction along the body central axis (B), the slot clamping member abutment surface can be located radially outside the imaginary shank portion circle.
In an end view of the slotting tool body along the body central axis, the slot lower jaw abutment surface and the slot clamping member abutment surface can converge towards each other in a direction towards the flexibility recess, defining an acute slot abutment angle.
The cutter portion can be divided into a number N of cutter sub-portions. Each clamping portion can comprise a stop member which is located circumferentially between the resilient clamping member and the lower jaw member. The stop member and the resilient clamping member can be located on the same cutter sub-portion.
N can satisfy the condition: 2≤N≤9. The cutter portion can define an imaginary circumscribed cutter portion circle that is centered at the body central axis and that has a cutter portion diameter. The cutter portion diameter can be less than or equal to 35 mm.
N can satisfy the condition: N=3. The cutter portion diameter can be approximately equal to 20 mm.
The cutting insert can be longitudinally elongated in a direction defining an insert longitudinal axis, the cutting insert comprising opposing insert upper and lower surfaces and an insert peripheral surface extending therebetween, the insert peripheral surface comprising two opposing insert end surfaces connecting the insert upper and lower surfaces and two opposing insert side surfaces also connecting the insert upper and lower surfaces. The cutting insert can comprise an insert longitudinal plane containing the insert longitudinal axis, passing between the insert side surfaces, and intersecting the insert upper and lower surfaces and also intersecting the opposite insert end surfaces. The cutting insert can comprise a cutting portion located at one end of the cutting insert, the cutting portion comprising a cutting edge formed at the intersection of the insert upper surface and one of the two insert end surfaces. The insert upper and lower surfaces can comprise insert upper and lower abutment surfaces, respectively. The insert receiving slot can be defined by an elongated slot peripheral surface comprising a slot lower jaw abutment surface located on the lower jaw member. The slot peripheral surface can further comprise a slot clamping member abutment surface located on the resilient clamping member. The slot clamping member abutment surface can abut the insert upper abutment surface. The slot lower jaw abutment surface can abut the insert lower abutment surface.
The insert end surface opposite the cutting portion can further comprise an insert stop surface which is closer to the insert upper surface than to insert lower surface, the insert stop surface being planar. Each clamping portion can comprise a stop member which is located circumferentially between the resilient clamping member and the lower jaw member. The cutter portion can be divided into a number N of cutter sub-portions. The stop member and the resilient clamping member can be located on the same cutter sub-portion. The slot peripheral surface can further comprise a slot radial stop surface located on the stop member. The slot radial stop surface can abut the insert stop surface.
The cutting insert can comprise an additional cutting portion such that the cutting insert includes two cutting portions, an active cutting portion and a non-active cutting portion, the two cutting portions being formed at opposite ends of the cutting insert. The insert upper surface can include an additional insert upper abutment surface, such that the insert upper surface includes two insert upper abutment surfaces, an active and non-active insert upper abutment surface, the active insert upper abutment surface being located further from the active cutting portion than the non-active insert upper abutment surface, with the slot clamping member abutment surface abutting the active insert upper abutment surface. The insert end surface at the active cutting portion can include an additional insert stop surface, such that the cutting insert includes two insert stop surfaces, an active and non-active insert stop surface, the active insert stop surface being located at the non-active cutting portion, with the slot radial stop surface abutting the active insert stop surface.
For a better understanding of the present application and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity, or several physical components may be included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
In the following description, various aspects of the subject matter of the present application will be described. For purposes of explanation, specific configurations and details are set forth in sufficient detail to provide a thorough understanding of the subject matter of the present application. However, it will also be apparent to one skilled in the art that the subject matter of the present application can be practiced without the specific configurations and details presented herein.
Attention is first drawn to
It is noted that the term “rotary slot cutting tool” as used herein may be replaced with other terms applicable in the metal cutting field for such cutting tools, for example, “slotting cutter”, “slot milling cutter”, “slitting cutter”, “grooving cutter”, “slot mill cutter”, “groove milling cutter”, “side milling cutter”, “disc milling cutter”, and the like.
Reference is now made also to
It should be appreciated that use of the terms “forward” and “rearward” throughout the description and claims refer to a relative position in a direction of the body central axis B downwardly and upwardly, respectively, in
As shown in
As shown in
The cutter portion 26 includes a number N of clamping portions 32, angularly spaced apart about the body central axis B, where N is an integer greater than 1. The number N of clamping portions 32 can be arranged at the same axial position along the body central axis B in the forward-to-rearward direction. As seen in
Referring to
In accordance with some embodiments of the subject matter of the present application, each clamping portion 32 can include a stop member 39 which can be located circumferentially between the resilient clamping member 34 and the lower jaw member 36. Generally speaking, the stop member 39 is radially inward of the resilient clamping member 34 and the lower jaw member 36. The purpose of the stop member 39 is described later in the description.
Reference is further made to
Each insert receiving slot 38 is defined by an elongated slot peripheral surface 40 having ends that extend to the cutter portion peripheral surface 30. It is noted that the slot peripheral surface 40 is not continuous, since a flexibility recess extends to the insert receiving slot 38 (so as to interrupt the slot peripheral surface 40), described later in the description. The slot peripheral surface 40 extends between the forward and rearward cutter portion side surfaces 28a, 28b. The slot peripheral surface 40 includes a slot clamping member abutment surface 42 located on the resilient clamping member 34, for abutting a corresponding surface on the cutting insert 24. The slot peripheral surface 40 includes a slot lower jaw abutment surface 44 located on the lower jaw member 36, for abutting a corresponding surface on the cutting insert 24. The slot peripheral surface 40 includes a slot radial stop surface 46, for positioning the cutting insert 24 in an exact predetermined radial position. The slot radial stop surface 46 faces radially outwardly. The slot radial stop surface 46 is located on the stop member 39. In accordance with some embodiments of the subject matter of the present application, the slot radial stop surface 46 can be located circumferentially between the slot clamping member abutment surface 42 and the slot lower jaw abutment surface 44.
Referring to
Referring to
Reverting back to
In accordance with some embodiments of the subject matter of the present application, shank portion 56 can include a number N of non-recessed forward shank portions 62 formed by a part of the shank peripheral surface 58 that is non-recessed (notwithstanding the fact that they may be located in the annular groove 59). Like the forward shank recesses 60, the non-recessed forward shank portions 62 can be peripherally disposed. The non-recessed forward shank portions 62 can be located between two circumferentially adjacent forward shank recesses 60 and axially adjacent the cutter portion 26. The number of non-recessed forward shank portions 62 can match the number of forward shank recesses 60. Each non-recessed forward shank portion 62 can be located between two circumferentially adjacent forward shank recesses 60. That is to say, the forward shank recesses 60 and the non-recessed forward shank portions 62 can alternate in a circumferential direction. The non-recessed forward shank portion 62 can be angularly spaced apart from each other about the body central axis B.
As seen in
In accordance with some embodiments of the subject matter of the present application, the resilient clamping member 34 of each clamping portion 32 can be axially adjacent a respective forward shank recess 60. That is to say, the free end of the resilient clamping member 34 is not connected to any part of the shank portion 56. As seen in
In accordance with some embodiments of the subject matter of the present application, a radially inward portion of each insert receiving slot 38 merges on one side thereof (i.e. the side of the insert receiving slot 38 that opens out to the rearward cutter portion side surfaces 28b) with a respective forward shank recess 60.
In accordance with some embodiments of the subject matter of the present application, in a direction along the body central axis B, the imaginary shank portion circle CS can intersect all the insert receiving slots 38. In particular, for any given for any given clamping portion (32), the imaginary shank portion circle CS can intersect the slot lower jaw abutment surface 44. The slot clamping member abutment surface 42 can be located radially outside the imaginary shank portion circle CS. The slot radial stop surface 46 can be located radially inside the imaginary shank portion circle CS. The slot key and resilience portions 50, 54 can be located radially inside the shank portion circle CS.
The cutter portion 26 further includes a flexibility recess 64 recessed in the forward cutter portion side surface 28a. Stated differently, the flexibility recess 64 is recessed relative to the forward cutter radial plane P″ and thus opens out to the forward cutter portion side surface 28a. Advantageously, the flexibility recess 64 increases the clamping forces applied on the cutting insert 24 by the clamping member 34.
As seen in
Referring to
In accordance with some embodiments of the subject matter of the present application, the flexibility recess 64 can be centrally located on the forward cutter portion side surface 28a. The flexibility recess 64 can be intersected by the body central axis B. Specifically, the body central axis B can intersect the recess base surface 66. The recess peripheral wall surfaces 68 can extend about the body central axis B.
As seen in
The flexibility recess 64 extends to (i.e. intersects) each of the insert receiving slots 38. Stated differently, the flexibility recess 64 connects the insert receiving slots 38 with each other. By virtue thereof, the cutter portion 26 is divided into a number N of cutter sub-portions 70. In a cross-sectional view taken in a median cutter radial plane P through both the flexibility recess 64 and the cutter portion peripheral surface 30, the cutter sub-portions 70 are spaced apart from each other. In accordance with some embodiments of the subject matter of the present application, two adjacent cutter sub-portions 70 can be spaced apart from each other by a respective insert receiving slot 38 and a portion of the flexibility recess 64. Each cutter sub-portion 70 can be defined circumferentially in a sequential order by a portion of the cutter portion peripheral surface 30, a portion of the slot peripheral surface 40 from a first insert receiving slot 38, one of the recess peripheral wall surfaces 68, and a portion of the slot peripheral surface 40 from a second insert receiving slot 38, the first and second insert receiving slot 38 being adjacent to each other.
Referring to
Each cutter sub-portion 70 can include a prong hole 31, for receiving a displacement prong 51a of an insertion key 52 when attaching the cutting insert 24 to the cutter portion 26, as described later in the description.
It is noted that, each clamping portions 32 spans over two adjacent (i.e. different) cutter sub-portions 70. Specifically, for any given clamping portion 32, the clamping member 34 and the lower jaw member 36 are located on two adjacent cutter sub-portions 70 and circumferentially face each other. In accordance with some embodiments of the subject matter of the present application, the stop member 39 and the resilient clamping member 34 can be located on the same cutter sub-portion 70.
Reference is now made to
The insert peripheral surface 88 includes two opposing insert end surfaces 90 that connect the insert upper and lower surfaces 84, 86. The insert peripheral surface 88 includes two opposing insert side surfaces 92 that connect the insert upper and lower surfaces 84, 86. The insert longitudinal axis A intersects the insert end surfaces 90 and extends between the insert side surfaces 92 (
As seen in
The cutting insert 24 includes a cutting portion 94a located at one end of the cutting insert 24. In accordance with some embodiments of the subject matter of the present application, the cutting insert 24 can further include one additional cutting portion 94b such that the cutting insert 24 includes two cutting portions 94a, 94b, an active cutting portion 94a (constituting the cutting portion 94a) and a non-active cutting portion 94b. The two cutting portions 94a, 94b are located at opposite ends of the cutting insert 24. Stated differently, the cutting insert 24 is double-ended and can be indexed by 180° rotation about the insert central axis F (i.e. the active cutting portion 94a becomes the non-active cutting portion 94b and vice versa). The two cutting portions 94a, 94b can be identical. It is understood in the following description that any feature that relates to a single cutting portion 94a can also relate to the other cutting portion 94b if present.
The cutting portion 94a includes a cutting edge 96a located at the cutting portion 94a. Specifically, the cutting edge 96a is formed at the intersection of the insert upper surface 84 and one of the two insert end surfaces 90. A portion of the insert end surface 90 adjacent the cutting edge 96a serves as a relief surface. Likewise, a portion of the insert upper surface 84 adjacent the cutting edge 96a serves as a rake surface. When the cutting insert 24 is releasably and resiliently clamped in the insert receiving slot 38, the cutting edge 96a of the active cutting portion 94a is located beyond the radial projection of the cutter portion 26 (i.e. beyond the imaginary circumscribed cutter portion circle CC). Preferably, such radial projection is no more than 1 mm. As seen in
Each insert side surface 92 bulges outwardly at the cutting portion 94a. That is to say, the cutting portion 94a includes two insert lateral extensions 98 which project laterally in a direction away from the insert longitudinal plane P1 (i.e. perpendicular to the insert longitudinal plane P1), from opposite sides of the cutting insert 24. The cutting edge 96a extends onto the two insert lateral extensions 98. When a double-ended cutting insert 24 is retained in an insert receiving slot 38 the wide lateral extension 98 belonging to the non-active cutting portion 94b located at the radially inner portion of the insert receiving slot 38, protrudes into the forward shank recess 60. Thus, one function of the forward shank recess 60 is to accommodate, and thus provide clearance for, the inactive lateral extension 98.
The insert end surface 90 opposite the cutting portion 94a includes an insert recessed portion 100 having an insert key surface 102, configured for abutment with the displacement prong of the key (not shown) used for extracting the cutting insert 24 from the insert receiving slot 38. The insert key surface 102 is closer to the insert lower surface 86 than to the insert upper surface 84. In accordance with some embodiments of the subject matter of the present application, the insert key surface 102 can be located entirely below the insert median plane M. In a side view of the cutting insert 24, perpendicular to the insert longitudinal axis A (i.e.
In accordance with some embodiments of the subject matter of the present application, the insert end surface 90 opposite the cutting portion 94a can include an insert stop surface 104a, for contact with the slot radial stop surface 46. The insert stop surface 104a can be closer to the insert upper surface 86 than to the insert lower surface 86. The insert stop surface 104a can be planar. It is understood that in a double-ended cutting insert, such as seen the figures, both opposite end surfaces 90 are provided with a recessed portion 100 having a key surface 102. Likewise, the insert end surface 90 opposite the non-active cutting portion 94h can include an insert stop surface 104b, such that the cutting insert 24 includes two insert stop surfaces 104a, 104b, an active insert stop surface 104a (constituting the insert stop surface 104a), located at the non-active cutting portion 94b, and a non-active insert stop surface 104b located at the active cutting portion 94a.
Further in the configuration where the cutting insert 24 is double-ended, the cutting insert 24 includes an additional cutting edge 96b, such that the cutting insert 24 has two cutting edges, an active cutting edge 96a (constituting the cutting edge 96a), located at the active cutting portion 96a and a non-active cutting edge 96b located at the non-active cutting portion 94b. The insert upper surface 84 can include an additional insert upper abutment surface 84b such that the insert upper surface 84 includes two insert upper abutment surfaces, an active insert upper abutment surface 84a (constituting the insert upper abutment surface 84a) and a non-active insert upper abutment surface 84b. The two insert upper abutment surface 84a, 84b can be axially offset from each other, along the insert longitudinal axis A. The active insert upper abutment surface 84a can be located further from the active cutting portion 94a than the non-active insert upper abutment surface 84b. Each insert upper abutment surface 84a, 84b slopes towards the insert longitudinal axis A in a direction towards its closest cutting edge 96a, 96b, i.e., it slopes towards the insert median plane M. Thus, the two insert upper abutment surfaces 84a are inclined (i.e. non-parallel) with respect to each other.
Reverting to
Referring to
Referring to
It is noted that the flexibility recess 64 advantageously provides enough flexibility to the clamping members 34 so that they can be displaced enough to allow insertion of all cutting inserts 24 into their respective insert receiving slot 38 while the clamping members 34 are rigid enough to firmly clamp the cutting insert 24. This advantage is particularly relevant for small diameter tools (e.g. where the cutter portion diameter DC is less than or equal to 35 mm). In such small sized cutting tools, the number of insert receiving slots is restricted and it is typical that Nis greater than or equal to two and less than or equal to nine (i e. N satisfies the condition: 2≤N≤9). In a particular, N can be equal to three (i.e. N=3), and the cutter portion diameter DC can be approximately 20 mm. However, the invention is not limited to such range(s) and/or value(s).
Although the subject matter of the present application has been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the spirit or scope of the invention as hereinafter claimed.
