GB1574657A - Boring bar - Google Patents
Boring bar Download PDFInfo
- Publication number
- GB1574657A GB1574657A GB953477A GB953477A GB1574657A GB 1574657 A GB1574657 A GB 1574657A GB 953477 A GB953477 A GB 953477A GB 953477 A GB953477 A GB 953477A GB 1574657 A GB1574657 A GB 1574657A
- Authority
- GB
- United Kingdom
- Prior art keywords
- bit
- boring bar
- bore
- holder
- bit holder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B29/00—Holders for non-rotary cutting tools; Boring bars or boring heads; Accessories for tool holders
- B23B29/03—Boring heads
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Cutting Tools, Boring Holders, And Turrets (AREA)
- Drilling Tools (AREA)
- Earth Drilling (AREA)
Description
(54) BORING BAR
(71) We, KOMET STAHLHALTER-UND WERKZEUGFABRIK ROBERT BREUNING GmbH,
a joint'stock company organised under the laws of the Federal Republic of Germany,
of 7122 Besigheim, Auf dem Kies 3, Federal
Republic of Germany, do hereby declare the
invention, for which we pray that a patent
may be granted to us, and the method by
which it is to be performed, to be parti
cularly described in and by the following statement: The invention relates to a boring bar, and
especially, although not exclusively, to a
boring bar for working metal.
A known boring bar (U.S. Patent Specifi
cation 2,630,725), has a bit holder which is
of substantially rectangular form as seen in plan view. An exchangeable polygonal bit is fixed at one corner of this rectangle by
means of a clamping screw which is passed
through a central bore in the bit. In the
region of the diagonally opposite corner, the
bit holder has a threaded bore for screwing
in a retaining screw by means of which it is fixed to the boring bar. This known bit
holder is relatively large and requires a
correspondingly large opening in the boring
bar. As a result, the boring bar is greatly
weakened, in particular when, for the ar
rangement of a ring of bit holders substan
tially in a cross-sectional plane of the boring bar, a plurality of such openings is required.
Moreover, the bit holders and the openings
therefor in the boring bar are difficult to produce because of their rectangular and par4lelepipedal shapes.
According to the present-invention there is
provided a boring bar having at least one ex
changeable polygonal bit held against abut
ment surfaces in a recess provided in a bit
holder by means of a clamping screw passed
through the said bit, 'the boring bar having
an opening'shaped to receive the bit holder
in which the bit holder is fixed to the boring
bar by means of a retaining screw, wherein
the opening is a blind- -bore extending. sub
stantially pcrpendicularlqi to the axial direc
tion of the boring bar - and - having a cylin
drical wall and a substantially plane bottom,
the bit holder having a rear cylindrical part
of a circular cross-section fitting into the
blind bore and, adjacent thereto, a front part
of substantially semi-circular cross-section
of the same diameter as the rear part, the
recess for the bit being provided in the dia
metric surface of this front part, a bore for
the retaining screw extending parallel to the
axis of the bit holder being provided in that
zone of the rear part which projects laterally
beyond the bit, and a threaded bore for the
retaining screw being provided in the bottom
of the blind bore.
The blind bore can be produced in simple
manner, and so also can the partly cylin
drical and partly semi-cylindrical bit holder.
Moreover, the bit holder can have relatively
small dimensions, so that the opening or blind bore in the boring bar also has small
dimensions and, consequently, the cross
section of the boring bar is not substantially
weakened. Finally, the blind bore offers a
good and secure support for the bit holder.
In order to keep these dimensions of the
bit holder and also of the blind bore as
small as possible, that zone of the rear
cylindrical part which projects laterally be
yond the bit borders advantageously directly
on the bit and is in the form of a semi
circular disc which'is narrow in the axial
direction.
The invention will now be described in
more detail, solely by way of example, with
reference to the accompanying drawings in
which
Fig. 1 is a partial side view of the boring
bar;
Fig. 2 is a cross-section on the line 11-Il of Fig. 1; and Ag. 3 is a partial longitudinal section on
the line IIIIII- of Fig. 1.
In The drawings, there is shown a boring
bar 1 which has a circular cross-section. The
boring bar may be equipped with one or
more exchangeable polygonal bits or cutting
inserts 2. The bits 2 arse formed of hard
metal. In the embodiment shown in the
draw three such bits are arranged in
a so-called cutting-edge ring, their cutting
edges being disposed in a common-cross
sectional plane of the boring bar. Since all
three bits 2 are connected to the boring bar in the same way, only the connection of one
of these parts-is described hereinafter.
A bit holder '3 serves to fix the bit 2 to the boring bar 1, the holder being arranged in a
blind bore 4 with a cylindrical wall 4a and a
substantially plane bottom 4b in the boring
bar 1. The bit holder 3 has a rear cylindrical
part 3a with a circular cross-section fitting
into the bore 4, and a front part 3b with
a substantially semi-circular cross-section of
the same diameter as the cylindrical part 3a
Both the parts 3a and 3b have - the same
diameter as the bore 4, A recess 5 with
abutment surfaces 6 for the bit 2 is provided
in the front part 3b. The bit 2 is provided
with a central bore 7 through which there
extends a clamping screw 8 which is screwed
into a threaded bore 9 in the bit holder 3.
The -bit holder has in that zone 31a of the
rear part 3a which projects beyond the bit
2 a bore 10 extending parallel to the axis of
the bit holder 3. A threaded bore 11 in line
with the bore 10- is provided in the bottom
4b of the bore 4. A retaining screw 12 passed
through the bore 10 is screwed into this bore
11 and serves to fix the bit holder 3 in the
bore 4. Since the retaining screw 12 is arranged eccentrically with respect to the axis
of the bit holder 3 and to the blind bore 4,
the retaining screw 12 also serves as a means
securing the bit holder 3 against twisting. As
can be seen in particular from Fig. 2, the bit holder 3 is supported well and securely alomost over its entire length in the blind
bore 4.
Advantageously, that zone 31a of the rear cylindrical part 3a which projects beyond the bit 2 borders directly thereon and is in
the form of a semi-circular disc which is
narrow in the axial direction. In this way,
very small dimensions of the bit holder are obtained in conjunction with very great
stability.
So that the boring bar 1 may be weakened
as little as possible by the bit holder or
holders, the diameter D of the blind bore 4
and of the bit holder 3 is advantageously
approximately as great as its length L.
In order also to ensure reliable chip removal, the boring bar 1 has above the bit
a recess 13 extending perpendicularly to the
axis of the blind bore 4. Due to this recess
13, the clamping screw 8 is accessible from above without the bit holder having to be
taken out of the boring bar 1.
The axis of the blind bore':4 e-xtends--sub- stantially perpendicularly to the axis of the
boring bar 1 and intersects the axis of the
boring bar. It would also be conceivable,
however, to arrange the axis of the blind
bore at a distance from the axis of the boring
bar. The axis of the bit holder 3, however,
always extends substantially parallel to the
top of the bit 2, unless the bit is inclined
a little with respect to the axis of the bit
holder in order to produce a positive or
negative cutting angle.
Claims (5)
1. A boring bar having at least one exchangeable polygonal bit held against abut
ment surfaces in a recess provided in a bit
holder by means of a clamping screw passed
through the said bit, the boring bar having
an opening shaped to receive the bit holder
in which the bit holder is fixed to the boring
bar by means of a retaining screw, - wherein
the opening is a blind tore extending sub
stantially perpendicularly to the axial direc
tion of the boring bar and having a cylin drical wall and a - a-substantially plane bottom, the bit - holder having a rear cylindrical part
of a circular cross-section fitting into the
blind bore and, adjacent thereto, a front part
of substantially semi-circular cross-section
of the same diameter as the rear part, the recess for the bit being provided in the dia
metric surface of this front part, a bore for the retaining screw extending parallel to the axis of the bit holder being provided in that zone of the rear part which projects laterally beyond the bit, and a threaded bore for the
retaining screw being provided in the bottom of the blind bore.
2. A boring bar according to claim 1, qherein that zone of the rear cylindrical part which projects laterally beyond the bit borders directly on the bit and is in the
form of a semi-circular disc which is narrow
in the axial direction.
3. A boring bar according to claim 1 or 2, wherein the diameter of the blind bore and of the bit holder is approximately as great as the length of the latter.
4. A boring bar according to claim 1, wherein the boring bar has above the bit
a recess extending perpendicularly to the
axis of the blind bore.
5. A boring bar according to claim 1 and substantially as described hereinbefore
with reference to and as shown in the accompanying drawings.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19767607041 DE7607041U1 (en) | 1976-03-09 | 1976-03-09 | BORING BAR, IN PARTICULAR FOR METAL WORKING |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1574657A true GB1574657A (en) | 1980-09-10 |
Family
ID=6662899
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB953477A Expired GB1574657A (en) | 1976-03-09 | 1977-03-07 | Boring bar |
Country Status (7)
Country | Link |
---|---|
JP (1) | JPS52111073A (en) |
CH (1) | CH597952A5 (en) |
DE (1) | DE7607041U1 (en) |
FR (1) | FR2343542A1 (en) |
GB (1) | GB1574657A (en) |
IT (1) | IT1117056B (en) |
SE (1) | SE417797B (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1252033A (en) * | 1959-04-28 | 1961-01-27 | Rough Surface Heat Exchanger Tubes | |
DE2848230B2 (en) * | 1978-11-07 | 1980-09-18 | Komet Stahlhalter- Und Werkzeugfabrik Robert Breuning Gmbh, 7122 Besigheim | Tool holder, in particular for boring |
DE7904992U1 (en) * | 1979-02-22 | 1980-07-31 | Komet Stahlhalter- Und Werkzeugfabrik Robert Breuning Gmbh, 7122 Besigheim | DRILLING TOOL |
DE8000947U1 (en) * | 1980-01-16 | 1981-07-09 | Komet Stahlhalter- Und Werkzeugfabrik Robert Breuning Gmbh, 7122 Besigheim | IN A HOLDER OF A MACHINE TOOL, ESPECIALLY TURNING TOOL, INSERTABLE INSERT HOLDER |
IL76241A (en) * | 1985-08-28 | 1988-08-31 | Iscar Ltd | Metal cutting tool |
-
1976
- 1976-03-09 DE DE19767607041 patent/DE7607041U1/en not_active Expired
-
1977
- 1977-01-14 IT IT6708477A patent/IT1117056B/en active
- 1977-01-17 CH CH51877A patent/CH597952A5/xx not_active IP Right Cessation
- 1977-01-26 FR FR7702130A patent/FR2343542A1/en active Granted
- 1977-02-08 SE SE7701380A patent/SE417797B/en not_active IP Right Cessation
- 1977-03-07 GB GB953477A patent/GB1574657A/en not_active Expired
- 1977-03-08 JP JP2535777A patent/JPS52111073A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
FR2343542B1 (en) | 1981-01-09 |
JPS52111073A (en) | 1977-09-17 |
SE417797B (en) | 1981-04-13 |
JPS5546801B2 (en) | 1980-11-26 |
IT1117056B (en) | 1986-02-10 |
DE7607041U1 (en) | 1977-08-25 |
SE7701380L (en) | 1977-09-10 |
FR2343542A1 (en) | 1977-10-07 |
CH597952A5 (en) | 1978-04-14 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |