U.S. patent application number 16/132876 was filed with the patent office on 2020-03-19 for swiss turning insert, swiss tool holder and assembly.
This patent application is currently assigned to Iscar, Ltd.. The applicant listed for this patent is Iscar, Ltd.. Invention is credited to PHILIP SHAHEEN.
Application Number | 20200086393 16/132876 |
Document ID | / |
Family ID | 68072922 |
Filed Date | 2020-03-19 |
United States Patent
Application |
20200086393 |
Kind Code |
A1 |
SHAHEEN; PHILIP |
March 19, 2020 |
SWISS TURNING INSERT, SWISS TOOL HOLDER AND ASSEMBLY
Abstract
A swiss turning tool assembly includes an insert and a tool
holder. The tool holder includes a head portion which in turn
includes an insert pocket and a fastener hole opening out to a
flank side of the tool and to a pocket opening in the insert
pocket. The insert pocket also includes a tool clamping arrangement
which in turn includes a tool base surface and at least one tool
abutment surface forming an external acute angle with the tool base
surface. The insert includes an insert base surface which in turn
includes at least one insert abutment surface forming an internal
acute angle with the insert base surface. To achieve a clamped
position, a single fastener, accessed from the tool's flank side
abuts the insert.
Inventors: |
SHAHEEN; PHILIP; (Tarshila,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Iscar, Ltd. |
Tefen |
|
IL |
|
|
Assignee: |
Iscar, Ltd.
Tefen
IL
|
Family ID: |
68072922 |
Appl. No.: |
16/132876 |
Filed: |
September 17, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23B 27/1611 20130101;
B23B 27/1681 20130101; B23B 2205/12 20130101; B23B 2200/328
20130101; B23B 2200/0485 20130101; B23B 29/043 20130101; B23B
2200/125 20130101; B23B 2205/04 20130101 |
International
Class: |
B23B 27/16 20060101
B23B027/16 |
Claims
1. A swiss turning tool assembly comprising: an insert devoid of a
clamping through hole; and a tool holder; the insert comprising:
opposite rake and insert base surfaces and an insert flank surface
connecting the rake and insert base surfaces; a cutting edge formed
along at least a portion of an intersection of the insert flank
surface and the rake surface; and an insert clamping arrangement in
turn comprising a first insert abutment surface forming an internal
acute angle with the insert base surface; the tool holder
comprising: opposite front and rear tool ends; opposite upper and
lower tool sides connecting the front and rear tool ends; opposite
first and second flank tool sides connecting the front and rear
tool ends and the upper and lower tool sides; an elongated shank
portion defining a tool elongation axis; and a head portion
connected to the shank portion; the head portion comprising: an
insert pocket; a fastener hole having a fastener hole axis and
extending through at least one of the first and second flank tool
sides, the fastener hole opening out to a pocket opening in the
insert pocket; and a single fastener configured to bring the insert
into a clamped position on the insert pocket; the insert pocket
comprising a tool clamping arrangement which in turn comprises: a
tool base surface; and a first tool abutment surface forming an
external acute angle with the tool base surface; wherein: the
fastener is configured to occupy the fastener hole and protrude
into the insert pocket via said pocket opening and abut the insert
to bring the tool and insert clamping arrangements into a clamped
position; and wherein, in the clamped position: the fastener abuts
the insert; the first tool abutment surface abuts the first insert
abutment surface; and the tool base surface abuts the insert base
surface.
2. The tool assembly according to claim 1, wherein the fastener is
configured such that, upon abutting the insert, the insert is at
least partially rotated into the clamped position.
3. The tool assembly according to claim 1, wherein the insert
pocket comprises opposite front and rear pocket ends, the front
pocket end being closer to the front tool end than the rear pocket
end; and said pocket opening is located at the rear pocket end.
4. The tool assembly according to claim 3, wherein: the insert
further comprises: opposite front and rear insert sides, the rear
insert side being closer to the rear pocket end than the front
insert side; and opposite first and second flank insert sides; and
wherein said fastener abuts the insert at an intersection region of
the rear insert side and the first flank insert side.
5. The tool assembly according to claim 1, wherein: the insert
pocket opens out to the upper tool side and the first flank tool
side; the first tool abutment surface is closer to the first flank
tool side than the second flank tool side; and the head portion
comprises a pocket wall adjacent the first flank side which extends
higher than the first tool abutment surface.
6. The tool assembly according to claim 1, wherein: the tool
clamping arrangement further comprises: a second tool abutment
surface further from the front tool end than the first tool
abutment surface, and the first and second tool abutment surfaces
are each closer to a different one of the first and second flank
tool sides; and the insert clamping arrangement further comprises:
a second insert abutment surface spaced apart from the first insert
abutment surface, and the first and second tool abutment surfaces
respectively abut the first and second insert abutment surfaces, in
the clamped position.
7. The tool assembly according to claim 6, wherein: the insert
pocket opens out to the upper tool side and the second flank tool
side; the first tool abutment surface is closer to the first flank
tool side than the second flank tool side; the second tool abutment
surface is closer to the second flank tool side than the first
flank tool side; and the head portion comprises a pocket wall
adjacent the first flank side which extends higher than the first
tool abutment surface.
8. The tool assembly according to claim 6, wherein the second tool
abutment surface forms an external acute angle with the tool base
surface.
9. The tool assembly according to claim 1, wherein, in a top view
of the tool base surface, the first tool abutment surface is
substantially parallel with the tool elongation axis within
15.degree..
10. The tool assembly according to claim 1, wherein the insert
pocket has a basic elongate shape which is basically parallel with
the tool elongation axis.
11. The tool assembly according to claim 6, wherein the tool
clamping arrangement further comprises a third tool abutment
surface located between the first and second tool abutment
surfaces.
12. The tool assembly according to claim 11, wherein the third tool
abutment surface forms an external acute angle with the tool base
surface.
13. The tool assembly according to claim 1, wherein the insert is a
two-way indexable insert and is 180.degree. rotationally
symmetric.
14. The tool assembly according to claim 1, wherein a frontmost
portion of the cutting edge of the insert is a wiper, the wiper
being angled at a right-angle from an adjacent portion of the
cutting edge.
15. (canceled)
16. The tool assembly according to claim 1, wherein the insert is a
diamond shaped insert having a 55.degree. or smaller nose
angle.
17. The tool assembly according to claim 16, wherein the insert is
a diamond shaped insert having a 35.degree. nose angle.
18. The tool assembly according to claim 1, wherein the fastener
comprises a screw head portion and a threaded shank portion
connected thereto; the screw head portion comprising: a tool
receiving end formed with a tool receiving arrangement; an insert
abutment end comprising a chamfered corner; a head axial length LH
defined from the tool receiving end to the insert abutment end; and
a shank axial length LS defined along a threaded portion of the
threaded shank portion; wherein: the head axial length LH is equal
to or greater than half of the shank axial length LS.
19. The tool assembly according to claim 18, wherein the fastener's
threaded shank portion further comprises, adjacent to the screw
head portion, a relief portion having a diameter smaller than the
threaded part of the threaded shank portion.
20. The tool assembly according to claim 18, wherein the fastener's
screw head portion is formed with an annular recessed portion
located between the tool receiving end and the insert abutment
end.
21. The tool assembly according to claim 1, wherein the fastener
hole opens out to a pocket opening formed in the upper tool side.
Description
FIELD OF THE INVENTION
[0001] The subject matter of the present application relates to
so-called Swiss turning inserts, Swiss tool holders and Swiss
turning tool assemblies comprising same.
BACKGROUND OF THE INVENTION
[0002] So-called Swiss turning tool assemblies and their
components, are special purpose tools designed for use in
swiss-style CNC machines (lathes) which are typically used for high
precision machining applications. An example Swiss turning tool
assembly of the field to which the present application is directed
(Swiss turning assemblies for turning applications) is further
detailed in U.S. Pat. No. 9,901,986, assigned to the present
applicant and incorporated herein by reference for understanding
the unique requirements of Swiss tool assemblies.
[0003] Swiss tool assemblies achieve high precision is achieved by
the workpiece being held close to a bushing to minimize overhang
and maximize stability and structural strength. Hereinafter the
names "Swiss" or "Swiss turning" are sometimes omitted for
conciseness only, but it should be understood that the subject
matter of this application is specifically directed to only to
turning inserts, tool holders and assemblies designed for specific
Swiss-style machining.
[0004] The design of Swiss inserts is limited by the requirement to
machine very close to the bushing and other tool assemblies in a
gang 100 (see, e.g., FIGS. 1A and 1B of the present application,
the drawings of which, but not the numbers, correspond to figures
in U.S. Pat. No. 9,901,986).
[0005] As shown in FIGS. 1A and 1B, there are four tool assemblies
102 shown. Each tool assembly 102 comprises a tool holder 104 and a
turning insert 106. It is noted that turning inserts 106 are
subjected to higher lateral forces than parting-off or grooving
inserts, due to their also being used in turning operations (i.e.
lateral machining in the direction designated D.sub.L). It is
however noted, that turning inserts may also be configured with a
grooving capability. As noted above, the name "turning" may be
omitted for conciseness only, when referring to inserts
hereinafter.
[0006] The turning inserts 106 have a rake surface 108, above which
chips flow (not shown), and flank surfaces 110A, 110B. A screw hole
112 and 114 extend through the flank surfaces 110 to clamp each
insert 106 to a respective tool holder 104. A cutting edge 116 is
formed at an intersection of at least the externally located the
flank surface 110A and the rake surface 108.
[0007] Due to the inserts 106 being in close proximity to each
other in the gang 100, and directly above one another due to the
nature of Swiss-style CNC machining, the inserts do not have a
clamping hole, such as a screw hole, extending through the rake
surfaces 108 thereof but rather the screw holes 112 extend through
the flank surfaces 110 thereof for accessibility purposes. It will
be understood that such clamping arrangement (screw hole 112
extending through the insert's flank surfaces 110) avoids the
difficulty caused by the closely packed tool assemblies and is a
popular manner to secure a Swiss cutting insert.
[0008] Nonetheless, it will be noted that the cutting portion 118,
to use an improvised name for the front portion of the insert shown
by the arrow designated 118, is unsupported by the tool holder
104.
[0009] In the further prior art example shown in FIGS. 2A and 2B, a
prior art Swiss tool assembly 200 of the Applicant is shown.
[0010] Tool assembly 200 comprises a tool holder 204 and a turning
insert 206. The turning insert 206 has a rake surface 208, above
which chips flow (not shown), and flank surfaces 210.
[0011] Contrary to the previous example, the clamping arrangement
includes a clamping hole 212 extending through the rake surface
208, and clamping is achieved through rotation of a screw 214,
accessible through a flank surface 216 of the tool holder 204, and
not the insert's flank surfaces 210. The screw 214 causes a lever
218 that extends through the clamping hole 212 to move in a
backwards and downwards direction D1 to clamp the insert 206 to the
tool holder 204.
[0012] In contradistinction to the previous example, the insert 206
of tool assembly 200 is more supported by the tool holder 204 than
the previously described insert 106, nonetheless the clamping
arrangement thereof is considerably more complex and expensive.
[0013] It is an object of the present application to provide an
improved swiss turning insert, tool holder and tool assembly,
particularly with high structural stability yet a simpler and more
user friendly clamping arrangement.
SUMMARY OF THE INVENTION
[0014] In accordance with a first aspect of the subject matter of
the present application, there is provided a Swiss turning tool
assembly comprising: an insert; and a tool holder; the insert
comprising: opposite rake and insert base surfaces and an insert
flank surface connecting the rake and insert base surfaces; a
cutting edge formed along at least a portion of an intersection of
the insert flank surface and the rake surface; and an insert
clamping arrangement in turn comprising a first insert abutment
surface forming an internal acute angle with the insert base
surface; the tool holder comprising: opposite front and rear tool
ends; opposite upper and lower tool sides connecting the front and
rear tool ends; opposite first and second flank tool sides
connecting the front and rear tool ends and the upper and lower
tool sides; an elongated shank portion defining a tool elongation
axis; and a head portion connected to the shank portion; the head
portion comprising: an insert pocket; a fastener hole having a
fastener hole axis and extending through at least one of the first
and second flank tool sides, the fastener hole opening out to a
pocket opening in the insert pocket; and a single fastener
configured to bring the insert into a clamped position on the
insert pocket; the insert pocket comprising a tool clamping
arrangement which in turn comprises: a tool base surface; and a
first tool abutment surface forming an external acute angle with
the tool base surface; wherein: the fastener is configured to
occupy the fastener hole and protrude into the insert pocket via
said pocket opening and abut the insert to bring the tool and
insert clamping arrangements into a clamped position; and wherein,
in the clamped position: the fastener abuts the insert; the first
tool abutment surface abuts the first insert abutment surface; and
the tool base surface abuts the insert base surface.
[0015] It will be appreciated that the essence of the invention is
that a clamping is achieved via operation of a fastener accessed by
the flank tool side and that the provision of said first tool
abutment surface and second insert abutment surface provide a
downward clamping force such that only a single fastener can be
used.
[0016] To elaborate regarding the advantage of clamping the insert
via the flank tool side, accessing the fastener via the flank tool
side allows indexing and clamping of the insert without the tool
holder needing to be removed from a gang (notably problematic for
Swiss machining). It also allows the tool holder to have a high
structural stability (i.e. the tool holder located underneath and
along the side of the insert, more than the example in FIG. 1A), to
more fully support the insert (also of high importance to Swiss
machining). Additionally, the fastener not extending through a
clamping through hole in the insert means that the screw does not
have to be completely removed to index or replace the insert, i.e.
a so-called as a `no falling parts` design. Stated differently, the
tool assembly comprises a fastener hole extends through both of
first and second flank tool sides; a fastener is rotatable about a
fastener axis within a fastener hole; and in a clamped position, a
fastener axis neither intersects, nor passes through, the
insert.
[0017] Further the single fastener is a significant improvement in
design over the previously known arrangement in FIGS. 2A and
2B.
[0018] To summarize the advantage of the present invention over
prior art: a less complex tool clamping arrangement, i.e. operation
of a single fastening component, is provided over the example shown
in FIGS. 2A and 2B which requires more than one fastener component;
however, even though the production of the first insert and tool
abutment surfaces is more complex and expensive than the simple
insert and standard screw shown in FIGS. 1A and 1B, which also
allows insert removal without tool holder removal from a gang, a
more structurally supportive tool holder structure for the insert
is theoretically achieved. Thus a comparatively large cutting depth
can be achieved.
[0019] In accordance with a second aspect of the subject matter of
the present application, there is provided a Swiss tool holder
comprising: opposite front and rear tool ends; opposite upper and
lower tool sides connecting the front and rear tool ends; opposite
first and second flank tool sides connecting the front and rear
tool ends and the upper and lower tool sides; an elongated shank
portion defining a tool elongation axis; and a head portion
connected to the shank portion; the head portion comprising: an
insert pocket; a fastener hole extending through at least one of
the first and second flank tool sides and opening out to a pocket
opening in the insert pocket; and a single fastener.
[0020] In accordance with a third aspect of the subject matter of
the present application, there is provided a Swiss turning insert
comprising: opposite rake and insert base surfaces and an insert
flank surface connecting the rake and insert base surfaces; and an
insert clamping arrangement comprising a first insert abutment
surface forming an internal acute angle with the insert base
surface.
[0021] It will be understood that in the specification and claims,
the directions given are only for reference to other elements of
the same or other components and is not relative to the ground.
Similarly, when stating, for example, that the tool holder has
upper, lower, first and second flank sides, this should not be
construed to infer a square shape. Even, for example, a cylindrical
shank can be theoretically divided into such sides. It will be
understood that the purpose of such definitions is again to
understand how the insert is clamped and functions when machining,
i.e. relative directions to understand force applications. In cases
where a particular shape or geometry is important it will be
defined in geometric terms.
[0022] Preferably, the fastener is configured to abut the insert
such that the insert is at least partially rotated into the
clamping position. Alternatively or additionally, preferably the
insert pocket comprises opposite front and rear pocket ends, the
front pocket end being closer to the front tool end than the rear
pocket end; and in the clamping position there is abutment of the
fastener and the insert at the rear pocket end. More precisely,
preferably, the pocket opening opens out to the rear pocket end. In
some preferred embodiments with stopper insert and tool abutment
surfaces (described below) the fastener can be alternatively or
additionally configured to also abut the insert such that it is
moved towards the front tool end. Most preferably, the fastener can
abut the insert to rotate the insert and move it towards the front
tool end.
[0023] Advantageously, a threaded shank portion of the fastener can
comprise a relief portion adjacent to an abutment end of the
fastener. This assists to ensure the insert does not scrape the
threaded portion. Stated differently, the fastener's threaded shank
portion can comprise, adjacent to the screw head portion, a relief
portion having a diameter smaller than the threaded part of the
threaded portion.
[0024] In accordance with a fourth aspect of the subject matter of
the present application, there is provided a fastener for a Swiss
turning tool assembly comprising: a screw head portion and a
threaded shank portion connected thereto; the screw head portion
comprising: a tool receiving end formed with a tool receiving
arrangement; an insert abutment end comprising a chamfered corner;
a head axial length L.sub.H defined from the tool receiving end to
the insert abutment end; a shank axial length L.sub.S defined along
a threaded portion of the threaded shank portion; wherein
[0025] the head axial length L.sub.H is equal to or greater than
half of the shank axial length L.sub.S.
[0026] It will be understood that such fastener, designed for
abutment in an unusual manner, is advantageous due to the unusually
long head portion thereof, for stability.
[0027] Preferably, the screw head portion is formed with an annular
recessed portion, which assists in further defining abutment
regions of the fastener to the fastener hole in which it is
located.
[0028] The following preferences are applicable to each of the
aspects:
[0029] The insert can comprise opposite front and rear insert
sides, and opposite first and second flank insert sides. Preferably
the fastener can abut the insert at only the rear insert side, or
only an intersection region of the rear insert side and the first
flank insert side. If only the rear insert side is abutted (i.e. at
a rear pocket end) this can push the insert forward into the
clamped position. If the intersection region is abutted, this can
push the insert forward as well as rotate the insert into the
clamped position which is currently the most preferred
configuration. Notably, abutment at the rear end of the insert
allows advantageous compactness of the tool holder and consequently
tool assembly.
[0030] The tool clamping arrangement can further comprise a second
tool abutment surface further from the front tool end than the
first tool abutment surface, and the first and second tool abutment
surfaces are each closer to a different one of the first and second
flank tool sides. The insert clamping arrangement can further
comprise a second insert abutment surface spaced apart from the
first insert abutment surface. In the clamped position, the first
and second tool abutment surfaces respectively abut the first and
second insert abutment surfaces. Similarly, when the tool clamping
arrangement further comprises a third tool abutment surface and the
insert clamping arrangement comprises a third insert abutment
surface, they can abut each other in the clamping position.
[0031] Preferably, the insert pocket opens out to the upper tool
side and the first flank tool side and the first tool abutment
surface is closer to the first flank tool side than the second
flank tool side. It will be understood that the insert can be
primarily configured to work in a direction basically from the
first flank tool side towards the second flank tool side, and hence
support at the first flank tool side extra strength is
advantageous. Further, in such case it is preferable that a second
tool abutment surface, which is further from the front tool end
than the first tool abutment surface, is closer to the second flank
tool side than the first flank tool side.
[0032] The first tool abutment surface can be parallel or basically
parallel to the elongation axis. Stated differently. in a top view
of the tool base surface, the first tool abutment surface is
substantially parallel with the tool elongation axis within
15.degree. (i.e. .+-.15.degree.) preferably within 5.degree. (i.e.
.+-.5.degree.).
[0033] Preferably, the tool clamping arrangement further comprises
a second tool abutment surface forming an external acute angle with
the tool base surface. This can provide further stability to the
insert (restraining upward motion at two ends of the insert) and/or
can allow the insert to be indexable.
[0034] The second tool abutment surface can be parallel or
basically parallel to the elongation axis. Stated differently. in a
top view of the tool base surface, the second tool abutment surface
is substantially parallel with the tool elongation axis within
15.degree. (i.e. .+-.15.degree.) preferably within 5.degree. (i.e.
.+-.5.degree.).
[0035] Preferably the insert pocket has a basic elongate shape
which is basically parallel with the tool elongation axis. It will
be understood that an elongated shape is particularly suited to the
space constricted environment in which a Swiss turning tool
assembly operates.
[0036] Preferably, the head portion comprises a pocket wall extends
higher than the first tool abutment surface. Preferably the pocket
wall is adjacent to the first tool abutment surface. Stated
differently, preferably both the pocket wall and first tool
abutment surface are closer to the first flank tool side than the
second flank tool side. Preferably, the pocket wall extends axially
forward of an opposing wall adjacent the first flank tool side. The
opposing wall can only be located adjacent the rear pocket end such
that the insert pocket is open to the second flank tool side.
[0037] Preferably, the tool clamping arrangement can comprise a
stopper tool abutment surface (also called hereinafter a third tool
abutment surface, since in the shown example the tool clamping
arrangement already comprises two other tool abutment surfaces).
Preferably the third tool abutment surface can be located (e.g.
axially located parallel with the elongation axis) between the
first and second tool abutment surfaces. Preferably the third tool
abutment surface can form an external acute angle with the tool
base surface. The third tool abutment surface can be configured to
restrict movement of the insert parallel to the elongation
axis.
[0038] In a top view of the tool base surface, the first and third
tool abutment surfaces can form a third tool abutment surface angle
.beta.3 fulfilling the condition:
45.degree.<.beta.2<135.degree., more preferably
75.degree.<.beta.3<115.degree., and most preferably
85.degree.<.beta.3<95.degree..
[0039] Additionally, or alternatively, the third tool abutment
surface can be defined with respect to the elongation axis, i.e. it
can be transverse, preferably basically perpendicular or
perpendicular thereto. This transverse orientation, preferably
perpendicular, is for restricting movement of the insert in a
direction parallel with the elongation axis.
[0040] In embodiments where the insert is elongated and has an
insert elongation axis, in a bottom view of the insert base
surface, the first insert abutment surface is substantially
parallel with the insert elongation axis (.+-.15.degree.)
preferably within 5.degree. i.e. (.+-.5.degree.).
[0041] Preferably, the insert further comprises a second insert
abutment surface forming an internal acute angle with the insert
base surface. This can provide further stability to the insert
(restraining upward motion at two ends of the insert) and/or can
allow the insert to be indexable.
[0042] In embodiments where the insert is elongated and has an
insert elongation axis, in a bottom view of the insert base
surface, the second insert abutment surface is substantially
parallel with the insert elongation axis (.+-.15.degree.)
preferably within 5.degree. i.e. (.+-.5.degree.).
[0043] Accordingly, preferably, the insert can be a two-way
indexable insert further comprising a second insert abutment
surface forming an internal acute angle with the insert base
surface, the insert, at least with respect to the insert abutment
surfaces, can be 180.degree. rotationally symmetric.
[0044] One possibility for the first and second insert abutment
surfaces to allow the insert to be rotationally symmetric (whether
180 degrees or some other angle, e.g. if the insert is three-way
indexable, or four-way indexable etc.) is that the first and second
insert abutment surfaces can face the same rotational direction.
While a two-way indexable insert is currently the most preferred
option as it allows an elongated shaped insert for a constricted
area, higher indexability could provide a separate advantage of
additional indexing options which increases the value of an
insert.
[0045] Preferably the cutting edge of the insert can be 180.degree.
rotationally symmetric, however it is also conceivable that each
indexable end of the insert could have a different function.
[0046] Preferably the frontmost portion of the cutting edge is a
wiper. Stated differently, angled at a right-angle from the
adjacent portion of the cutting edge which extends along a flank
insert side.
[0047] Preferably the insert has a basic elongate shape. It will be
understood that an elongated shape is particularly suited to the
space constricted environment in which a Swiss turning tool
assembly operates. Further the slanted insert abutment surfaces
allow the insert to be clamped with the advantages stated above
which are not currently known to be available for Swiss turning
tools.
[0048] Preferably the insert can have a solid insert shape (stated
differently, the insert can be devoid of a clamping through hole).
This can allow a stronger insert for a given size. Another
advantage is that a smooth rake surface can allow unimpeded chip
flow.
[0049] Preferably, the insert can comprise a stopper insert
abutment surface (also called hereinafter a third insert abutment
surface, since in the shown example where the insert already
comprises two other insert abutment surfaces). Most preferably, a
single recess can comprise both the third insert abutment surface
and an insert base surface which extends adjacent thereto.
Preferably the third insert abutment surface can form an internal
acute angle with the insert base surface.
[0050] In a bottom view of the insert, the first and third insert
abutment surfaces can form an external insert abutment surface
angle .lamda. fulfilling the condition:
45.degree.<.lamda.<135.degree., more preferably
75.degree.<.lamda.<115.degree., and most preferably
85.degree.<.lamda.<95.degree..
[0051] It will be understood that in the clamped position, the only
contact areas of the insert and tool holder are the fastener and
the insert, the tool and insert base surfaces and the tool and
insert abutment surfaces (regardless of there being one, two or
three etc.). Thus the contact areas are as described above in the
first aspect. In embodiments where the insert clamping arrangement
further comprises a second insert abutment surface and the tool
clamping arrangement further comprises a second tool abutment
surface, in the clamped position there is also abutment of the
second tool abutment surface and the second insert abutment
surface. Similarly, in embodiments where the insert clamping
arrangement further comprises a third insert abutment surface and
the tool clamping arrangement further comprises a third tool
abutment surface, in the clamped position there is also abutment of
the third tool abutment surface and the third insert abutment
surface.
[0052] Preferably the insert can be an ISO D-type insert (having a
55.degree. angle) or smaller (e.g. a V-type insert having a
35.degree. angle).
[0053] It will be understood that although opposite first and
second flank tool sides connected to opposite upper and lower tool
sides are defined, this does not require the tool holder or the
shank thereof to have a quadrilateral shape but rather this
definition provides a relative location. For example a tool's shank
could be cylindrical, with the outer surface of each 90 degree
quadrant constituting one of the tool sides.
[0054] The fastener can be a screw comprising a screw head portion
and a threaded shank portion connected thereto. The fastener hole
can be formed with threading which corresponds to the threaded
shank portion.
[0055] A screw head portion can comprise opposite tool receiving
and insert abutment ends.
[0056] A screw head portion can comprise a head axial length
defined from the tool receiving end to the insert abutment end.
[0057] A threaded shank portion can comprise a shank axial length
defined along a threaded portion thereof.
[0058] Preferably, the head axial length is equal to or greater
than half of the shank axial length.
[0059] Preferably, the screw head portion further is formed with an
annular recessed portion located between the tool receiving end and
insert abutment end.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] For a better understanding of the subject matter 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:
[0061] FIG. 1A is a front view of a prior art gang comprising four
swiss-style tool assemblies;
[0062] FIG. 1B is a side view of the gang in FIG. 1A;
[0063] FIG. 2A is a side view of a different prior art swiss-style
tool assembly;
[0064] FIG. 2B is a top view of the tool assembly in FIG. 2A;
[0065] FIG. 3A is a side view of an example swiss-style tool
assembly according to the subject matter of the present
application;
[0066] FIG. 3B is a front view of the tool assembly in FIG. 3A;
[0067] FIG. 3C is a top view of the tool assembly in FIG. 3A;
[0068] FIG. 4A is a side view of a screw of the tool assembly in
FIG. 3A;
[0069] FIG. 4B is a perspective view of the screw in FIG. 4A;
[0070] FIG. 4C is a rear view of the screw in FIG. 4A;
[0071] FIG. 5A is a front perspective view of an insert of the tool
assembly in FIG. 3A, with intended abutment surfaces exemplified
with imaginary hatch lines;
[0072] FIG. 5B is a bottom view of the insert in FIG. 5A;
[0073] FIG. 5C is a front view of the insert in FIG. 5A;
[0074] FIG. 5D is a side view of the insert as shown in FIG.
5A;
[0075] FIG. 6A is a side view of a portion of a tool holder of the
tool assembly in FIG. 3A;
[0076] FIG. 6B is a front view of the tool holder in FIG. 6A;
[0077] FIG. 6C is a top view of a portion of the tool holder in
FIG. 6A;
[0078] FIG. 7A is a perspective view of a portion of the tool
holder in FIG. 6A, particularly the insert pocket with intended
abutment surfaces exemplified with imaginary dotted portions;
[0079] FIG. 7B is a similar perspective view of portion of the tool
holder in FIG. 7A;
[0080] FIG. 7C is a side view of the portion of the tool portion in
FIG. 7A;
[0081] FIG. 7D is a section view along line 7D-7D in FIG. 7C;
[0082] FIG. 8A is a section view along line 8A-8A in FIG. 7D;
[0083] FIG. 8B is a section view along line 8B-8B in FIG. 7D;
[0084] FIG. 8C is a section view along line 8C-8C in FIG. 7D;
[0085] FIG. 9A is a section view of the insert pocket, screw and
insert of the tool assembly FIG. 3A, in an unclamped position;
[0086] FIG. 9B is a transitional position of a view similar to FIG.
9A, with the screw having been moved further inside the insert
pocket to abut the insert and partially move the insert in a
clamped position; and
[0087] FIG. 9C is a similar view to FIGS. 9A and 9B, except that
the screw has been moved further inside the insert pocket to abut
the insert such that it is now secured in a clamped position in the
insert pocket.
DETAILED DESCRIPTION
[0088] Referring to FIGS. 3A to 3C, illustrated is a tool assembly
10 comprising an insert 12, a tool holder 14 and a fastener 16
(shown in FIGS. 4A-4C) for securing the insert 12 to the tool
holder 14.
[0089] The tool assembly 10 can optionally comprise a coolant
arrangement 18.
[0090] Notably, for the essential function of machining, only three
components are needed for the tool assembly 10, namely the insert
12, tool holder 14 and a single fastener 16. In the embodiment
shown, the fastener 16 has unitary one-piece construction.
Moreover, as discussed further below, the fastener abuts (i.e.,
directly contacts) the insert 12, without an intervening
element.
[0091] Referring to FIGS. 4A to 4C, the fastener 16 has a fastener
axis A.sub.W around which the fastener is rotatable. The fastener
is preferably a screw comprising a screw head portion 16A and a
threaded shank portion 16B connected thereto.
[0092] The screw head portion 16A can comprise opposite tool
receiving and insert abutment ends 16C, 16D. More precisely, the
tool receiving end 16C is formed with a tool receiving arrangement
16E (in this example a Torx.RTM. keyway).
[0093] Similarly, the insert abutment end 16D can comprise a
chamfered corner 16F designed to abut the insert 12 (FIG. 3A).
[0094] The screw head portion 16A can comprise a head axial length
L.sub.H defined from the tool receiving end 16C to the insert
abutment end 16D.
[0095] The threaded shank portion 16B can comprise a threaded
portion 16G, and a shank axial length L.sub.S is defined along the
threaded portion 16G.
[0096] Preferably, the head axial length L.sub.H is equal to or
greater than half of the shank axial length L.sub.S for abutment
purposes as will be explained below.
[0097] Additionally, preferably, the screw head portion 16A is
formed with an annular recessed portion 16H.
[0098] Advantageously, the threaded shank portion 16B comprises a
relief portion 16I (i.e., having an outer diameter which is smaller
than the diameter of the threading) which ensures that the fastener
16 can abut the insert 12 at only the intended insert abutment end
16D thereof (i.e., ensuring the insert 12 does not scrape the
threaded portion 16B).
[0099] Referring to FIGS. 3C and 5A to 5D, the insert 12 preferably
has a basic elongate shape with, for example, an ISO D-type shape
(having a 55.degree. angle represented as .theta.).
[0100] A central insert axis A.sub.I is shown in FIG. 3C, and an
insert elongation axis A.sub.E is shown in FIG. 5B.
[0101] In this example, the insert 12 is a two-way indexable insert
when rotated exactly (and only 180.degree. about the central insert
axis A.sub.I.
[0102] The insert 12 comprises opposite rake and insert base
surfaces 20, 22 and an insert flank surface 24 connecting the rake
and insert base surfaces 20, 22. The rake and base surfaces 20, 22
differ from one another in structure and function, and so the
insert 12 is single-sided.
[0103] A cutting edge 26 is formed along at least a portion of an
intersection of the insert flank surface 24 and the rake surface
20. In this example, as the insert 12 is two-way indexable, the
cutting edge has two identical portions 28, 30. Specifically, in
the preferred example each portion has a main (larger) cutting edge
28A, 30A for turning, and each portion has a frontmost portion
forming an auxiliary cutting edge 28B, 30B (which preferably but
optionally is configured as a wiper). Nonetheless, each auxiliary
cutting edge 28B, 30B can be provided a limited plunging
capability.
[0104] Notably, the insert elongation axis A.sub.E, in embodiments
where the insert is elongated, for the purposes of the
specification and claims, is not defined with respect to a cutting
edge which can be of various shapes but rather is defined as
parallel to, and extending midway between, the two longest sides
32A, 32B (FIG. 5B) of the insert 12.
[0105] The insert 12 further comprises an insert clamping
arrangement 34 which in this example, comprises first, second,
third and fourth insert abutment surfaces 34A, 34B, 34C, 34D. It
will be understood that to be functional, only the first insert
abutment surface 34A (which, as will be described below, in the
clamped position will be the closest insert abutment surface to a
front tool end 36A, FIG. 6C) would be sufficient. The second insert
abutment surface 34B (which, as will be described below, in the
clamped position will be the furthest insert abutment surface from
the front tool end 36A) is beneficial for stability of the insert
12, and in this present example in which the insert 12 is
indexable, additionally after indexing replaces the function of the
first insert abutment surface 34A. The third insert abutment
surface 34C assists in achieving the desired clamping position, but
like the second insert abutment surface 34B, is a preferred but
optional stopper. Unlike the other insert abutment surfaces, the
fourth insert abutment surface 34D has no function in the clamped
position described below and only after indexing replaces the
function of the third insert abutment surface 34C, to which it is
identical.
[0106] In the embodiment seen in FIGS. 5A-5D, the four insert
abutment surfaces comprise a pair of identical major insert
abutment surfaces 34A, 34B extending along the insert elongation
axis A.sub.E, and a pair of minor abutment surfaces 34C, 34D which
are transverse to the major abutment surfaces 34A, 34B. As the
insert 12 is two-way indexable, the first and second insert
abutment surfaces 34A, 34B are identical after 180.degree. rotation
about the central insert axis A.sub.I. Similarly, the third and
fourth insert abutment surfaces 34C, 34D are identical after
180.degree. rotation about the central insert axis A.sub.I. Thus in
the following description, everything stated about either the first
or second insert abutment surfaces 34A, 34B is correct for the
other, and everything stated about either the third or fourth
insert abutment surfaces 34C, 34D is correct for the other. This is
done for conciseness, and because some of the abutment surfaces are
easier shown than others in the drawings.
[0107] All of the first, second, third and fourth insert abutment
surfaces 34A, 34B, 34C, 34D respectively form first, second, third
and fourth internal acute angles .mu.A, .mu.B, .mu.C, .mu.D with
the insert base surface 22 (noting that .mu.B is not shown but is
identical to .mu.A after indexing and .mu.C is not shown but is
identical to .mu.D after indexing). As will be understood from the
drawings, in the present specification and claims, an "internal"
angle is measured inside the material of a component as shown, as
opposed to an "external" angle measured outside of the
material.
[0108] In FIG. 5B, both the first and second insert abutment
surfaces 34A, 34B (which project into the page) are shown to be
parallel with the insert elongation axis A.sub.E, although such
alignment is optional.
[0109] In the view of FIG. 5B, using imaginary extension lines, it
is shown the first and third insert abutment surfaces 34A, 34C can
form an external insert abutment surface angle .lamda.. The
external insert abutment surface angle .lamda. is in this example
is 90.degree., although such angle is optional. To perform as a
stopper, the third insert abutment surface 34C need only be
transverse to the first or second insert abutment surface 34A, 34B,
however, it will be understood, that an angle closer to a right
angle provides a securer stopping function.
[0110] While discussing insert abutment surfaces as shown by hatch
lines in FIG. 5A, attention is drawn to a fastener abutment surface
58. It will be understood that such surface could be of any desired
shape allowing for abutment. Further when a clamping position
includes the first abutment surface 34A being the abutment surface
closest to the front tool end 36A the fastener abutment surface 58
abutted by the fastener 16 is the one designated as "58A" in FIG.
5D. The identical abutment surface designated as 58B in FIG. 5A is
abutted when the insert 12 is subsequently indexed. Thus, the
active fastener abutment surface is remote from the from the tool
end 36A. Notably, in this preferred but non-limiting embodiment,
the fastener abutment surfaces 58A, 58B are located at an
intersection of the rear and flank insert sides, which is
beneficial for providing both rotational and translational motion
as described below.
[0111] Referring to FIGS. 6A to 7B, the tool holder 14 comprises
opposite front and rear tool ends 36A, 36B (FIG. 3C), opposite
upper and lower tool sides 36C, 36D connecting the front and rear
tool ends 36A, 36B; opposite first and second flank tool sides 36E,
36F connecting the front and rear tool ends 36A, 36B and the upper
and lower tool sides 36C, 36D; an elongated shank portion 38
defining a tool elongation axis A.sub.T (i.e. extending parallel
with the shank portion 38); and a head portion 40 connected to the
shank portion 38.
[0112] The head portion 40 comprises an insert pocket 42, which in
this example has a basic elongate shape which extends basically
parallel with the tool elongation axis A.sub.T.
[0113] The head portion 40 further comprises a fastener hole 44
(FIG. 6B) having a fastener hole axis A.sub.H (FIG. 7D). In the
shown embodiment, the fastener hole 44 extends through both the
first and second flank tool sides 36E, 36F. This is done for ease
of production. In other embodiments, not shown, the fastener hole
44 may extend between only one of two the flank tool sides 36E, 36F
and a pocket opening 46 in the insert pocket 42. As best seen in
FIG. 7A, the fastener hole 44 intersects the insert pocket 42 at
the pocket opening 46. Restated, the pocket opening 46 interrupts
the fastener hole 44.
[0114] The fastener hole 44 is accessed via an aperture 47A opening
out to the first tool side 36E. For ease of production, the
fastener hole 44 also opens out to a second aperture 47B at the
second tool side 36F. It will be understood that, if desired, a
fastener could be accessed by an aperture at the second tool side
36F instead of the first tool side 36E or a double ended fastener
could be provided which could be actuated from either side of the
tool holder 14.
[0115] Referring also to FIGS. 7C to 8C, the insert pocket 42
comprises a tool clamping arrangement 48 which in turn comprises a
tool base surface 52; and first, second and third tool abutment
surfaces 54A, 54B, 54C, each forming an external acute angle (CA,
CB, CC) with the tool base surface 52 as shown in FIGS. 8A to
8C.
[0116] As best shown in FIG. 6C, the first and second tool abutment
surfaces 54A, 54B, are, in this example, parallel to the tool
elongation axis A.sub.T, whereas, the third tool abutment surface
54C is perpendicular to the tool elongation axis A.sub.T. It will
be understood that it is necessary for the third tool abutment
surface 54C to be transverse to at least one of the others to
restrict movement of the insert 12 parallel to the tool elongation
axis A.sub.T.
[0117] Still referring to FIG. 6C, the insert pocket 42 further
comprises a rear pocket end 50A and a front pocket end 50B.
[0118] As most easily understood from FIGS. 7A and 7B, the insert
pocket 42 opens out to the upper tool side 36C and the second flank
tool side 36F and the first tool abutment surface 54A is closer to
the first flank tool side 36E than the second flank tool side 36F.
It will be understood that the main cutting direction D.sub.C (FIG.
3C) is basically in the direction from the second flank tool side
36F towards the first flank tool side 36E (i.e. transverse, more
precisely basically a right angle, to the elongation axis A.sub.T)
and hence it is more beneficial for the first tool abutment surface
54 to support the insert 12 against the forces applied thereon in
the opposite direction D.sub.D to the cutting direction
D.sub.C.
[0119] Preferably, the head portion 40 further comprises a pocket
wall 56 which extends higher than the first tool abutment surface
54A. It will be understood that the additional material
significantly strengthens the tool holder 14, and hence insert 12
held by it, against the forces applied thereon in the direction
D.sub.D.
[0120] Referring to FIGS. 5A and 7B the intended abutment surfaces
are schematically shown with imaginary dotted or hatched portions.
In addition to abutment of the fastener 16 (specifically the
chamfered corner 16F) abutting the insert 12 (specifically the
fastener abutment surface 58A) which will be described below, to
achieve the clamped position there is abutment of at least the
first tool abutment surface 54A with the first insert abutment
surface 34A, and the tool base surface 52 with the insert base
surface 22.
[0121] It will be understood that with the above-mentioned
abutments, an insert can be secured in a clamped position,
particularly because the first tool abutment surface 54A and first
insert abutment surface 34A are configured to bias the insert 12
towards the tool base surface 52.
[0122] Preferably, in the present example there is also abutment of
the second tool abutment surface 54B and the second insert abutment
surface 34B.
[0123] Since the abutment surfaces are slanted relative to the tool
base surface 52 and the insert base surface 22, to bring them to a
clamped position it is preferred that the fastener 16 abut the
insert 12 in such a manner that it partially rotates the insert
into the clamped position, as shown in the transition of the
positions of the insert 12 shown from FIG. 9A to 9B.
[0124] Further, preferably, there is also provided the third tool
abutment surface 54C which abuts the third insert abutment surface
34C. This provides a stopper effect to halt the insert 12 from
sliding forward in a forward direction D.sub.F (FIG. 3C) which is
basically parallel with the tool elongation axis A.sub.T. While the
third tool and insert abutment surfaces 54C, 34C are similarly
slanted relative to the tool and insert base surfaces 52, 22, it
will be understood that said slanting is less necessary than the
first and second tool and insert abutment surfaces 54A, 54B, 34A,
34B. Indeed, similar to the second tool abutment surface 54B and
the second insert abutment surface 34B, the third tool and insert
abutment surfaces 54C, 34C in their entirety are preferred but
optional. Nonetheless it will be understood that the second tool
abutment surface 54B and the second insert abutment surface 34B
significantly contribute to stability and are thus highly
preferred.
[0125] Referring also to FIGS. 9A to 9C, in operation, the fastener
16 in this example is moved by using a screwdriver (not shown) and
rotating the fastener 16 via the tool receiving arrangement
16E.
[0126] More precisely, such rotation moves the fastener 16 from an
initial position shown in FIG. 9A further into the fastener hole 44
to an intermediate position, as shown in FIG. 9B.
[0127] In FIG. 9B the chamfered corner 16F, abuts the fastener
abutment surface 58A at the pocket opening 46 (shown in FIG. 7A).
Such abutment moves the insert 12 towards the clamped position.
Specifically, in FIG. 9B, such movement includes rotation of the
insert 12 so that the first and second tool and insert abutment
surfaces 54A, 54B, 34A, 34B are brought into contact.
[0128] The chamfered corner 16F and fastener abutment surface 58A
are both configured (chamfered) such that their abutment both
rotates the insert 12 and also moves it in the forward direction
D.sub.F.
[0129] With continued rotation of the fastener 16, the insert 12 is
moved further in the forward direction D.sub.F until the clamped
position, shown in FIG. 9C, is reached. In such a clamped position,
the third tool abutment surface 54C abuts the third insert abutment
surface 34C which effectively halts movement of the insert 12.
[0130] As seen in FIG. 9A-9C, in the initial, intermediate and
clamped positions of the assembled tool, the fastener 16 occupies
the fastener hole 44 and extends along the fastener hole axis
A.sub.H. In some embodiments, the fastener hole axis A.sub.H is
coincident with the fastener axis A.sub.W. Also in some
embodiments, in an assembled tool in which the fastener hole 44
opens to both of the first and second flank tool sides 36E, 36F,
the fastener axis A.sub.W neither intersects, nor passes through,
the insert 12, even though the fastener 16 directly contacts the
insert 12.
[0131] Reverting to FIGS. 4A to 4C, to reduce stresses on the
fastener 16 the screw head portion 16A is configured to have an
unusually long head axial length L.sub.H to increase the defined
abutment area from the tool receiving end 16C to the insert
abutment end 16D. To further ensure the defined abutment (contact
areas) over a relatively long area, the fastener 16 is provided
with said annular recessed portion 16H.
[0132] Notably, clamping the insert 12 (as described above) or
unclamping it by rotating the fastener 16 in the opposite direction
is achieved by actuating only a single element, namely the fastener
16, and such actuation is via one of the flank tool sides (in this
example accessing the fastener hole 44 via the first flank tool
side 36E). Hence, the tool holder 14 does not need to be detached
from a gang (not shown) in order to access a fastener hole opening
out to, for example, the upper tool side 36C.
* * * * *