Machine tools abstract
A tool, in particular a fine-turning boring bar, for use in machine-tools,
includes a shank part (16) which can be coupled to a rotating tool
spindle, a head part (10) which is secured to the shank part (16)
so as to remain fixed during rotation and which can be adjusted
transversely with respect to the shank part (16), and a cutting
support (20) which can be radially adjusted for coarse positioning
purposes. Cylindrical fitting pins (28 30) provided with radial
face grooves (36 38) are formed facing each other on the shank
part (16) and the head part (10). A cross-coupling element (12)
arranged between the front ends of the fitting pins (28 30) has
radially mobile pairs of claws (40 42) which extend axially from
both sides and which engage in mutually perpendicular face grooves
(36 38) in the fitting pins (28 30). The two fitting pins (28
30) also engage in mutually eccentric fitting holes (32 34) of
an eccentric sleeve (18) which can rotate with respect to the head
part (10) and the shank part (16). The head part (10) and the shank
part (16) are clamped temporarily, with radial play, by the cross-coupling
element (12) and the eccentric sleeve (18) and then interconnected
by means of a clamping anchor (14) which passes through the bore
holes in the shank part (16), rotates in a thread (58) in the head
part (10) and rests against an abutment (62 64 66) in the region
of the shank part.
Machine tools claims
The embodiments of the invention in which an exclusive property
or privilege is claimed are defined as follows:
1. In a fine-turning boring bar for use in machine tools, comprising
a shank part which can be coupled to a rotating tool spindle, a
head part which is secured to the shank part so as to rotate therewith
and is adjustable transversely with respect to the shank part, and
a cutting support arranged in the head part, the improvement wherein
cylindrical fitting pins, which face one another and have radially
extending face grooves at their mutually adjacent ends, are formed
on the shank part and on the head part, wherein between the mutually
adjacent ends of the fitting pins there is arranged a cross-coupling
element with mobile coupling claws projecting axially from both
sides thereof and are radially movably received into the face grooves
on the fitting pins, which face grooves are aligned perpendicularly
with respect to one another, wherein the two fitting pins are received
into fitting holes of an eccentric sleeve which is rotatable relative
to the fitting pin, which fitting holes are eccentric to one another,
and wherein the head part and the shank part are connected with
the intermediate clamping of the coupling element and/or the eccentric
sleeve by means of a clamping anchor extending with radial clearance
through holes in the shank part and in the cross-coupling element
and engaging a thread on the head part and supported against an
abutment in the area of the shank part.
2. The tool according to claim 1 wherein the longitudinal axis
of the fitting hole receiving the fitting pin of the shank part
is aligned with the axis of rotation of the tool.
3. The tool according to claim 1 wherein the cross-coupling element
arranged inside of the eccentric sleeve is constructed as an annular
piece with pairs of claws axially projecting to both sides and angularly
spaced at 90.degree. relative to one another.
4. The tool according to claim 1 wherein the claw flanks of the
cross-coupling element widen inclined from their root toward their
tip.
5. The tool according to claim 1 wherein the shank part has a
stepped hole, and wherein between a shoulder of the stepped hole
and a head of the clamping anchor there are arranged spring means
preferably constructed as a set of springs.
6. The tool according to claim 5 wherein a spacer ring is arranged
between the clamping-anchor head and the set of springs.
7. The tool according to claim 5 wherein the stepped hole is closed
off with an end screw on the side of the clamping-anchor head.
8. The tool according to claim 7 including a fill piece filling
the stepped hole and preferably consisting of a heavy material,
like lead.
9. The tool according to claim 1 including a coupling part connectable
to the end of the shank part on the side of the spindle, with a
flat surface arranged on the side of the spindle and perpendicular
with respect to the axis of rotation of the tool and with a fitting
pin projecting axially beyond the flat surface.
10. The tool according to claim 9 at least one of the clamping
anchor and the fill piece, the end screw and the coupling part have
an axial cooling-medium channel leading to the chip flute of the
tool.
11. The tool according to claim 10 wherein the clamping anchor
can be adjusted in its clamping force by means of an adjusting tool
insertable through the cooling-medium channel.
12. The tool according to claim 5 wherein the clamping-anchor
head has a peripheral groove to receive an elastic gasket ring resting
against the inner surface of the stepped hole.
13. The tool according to claim 1 including an elastic gasket
ring resting on oppositely lying faces of the end screw and of the
clamping-anchor head and sealing off the cooling-medium channel
to the exterior.
14. The tool according to claim 13 wherein the gasket ring is
supported in radial direction on an axially projecting hollow pin
formed on the clamping-anchor head.
15. The tool according to claim 9 including an elastic gasket
ring resting on oppositely lying faces of the shank part and of
the coupling part and supported in radial direction on the end screw
projecting beyond the shank part.
16. The tool according to claim 1 wherein the eccentric sleeve
has an outer multi-surface section for the engagement by an adjusting
wrench.
17. The tool according to claim 1 wherein the eccentric sleeve
carries a scale ring at its end facing toward the shank part or
toward the head part.
18. The tool according to claim 1 wherein the cutting support
is fixedly and radially adjustably arranged on the head part.
Machine tools description
FIELD OF THE INVENTION
The invention relates to a tool, in particular a fine-turning boring
bar, for use in machine tools, comprising a shank part which can
be coupled to a rotating tool spindle, a head part which is connected
to the shank part so as to rotate therewith and can be adjusted
transversely with respect to the shank part, and a cutting support
arranged in the head part.
BACKGROUND OF THE INVENTION
The adjusting mechanism for the fine adjustment of the head part
requires relatively much space in tools of this type. Since the
structural parts of the adjusting mechanism cannot be randomly reduced
in size, the tool diameter has strict requirements. In addition,
the precision of the fine feed in conventional adjusting mechanisms
often leaves much to be desired.
SUMMARY OF THE INVENTION
The basic purpose of the invention is to provide a tool of the
above-mentioned type which, even in the case of a very small tool
diameter, has a high precision feed and a sufficient stiffness.
To attain this purpose, the invention suggests that cylindrical
fitting pins are formed on the shank part and on the head part of
the tool, which fitting pins face one another and have radially
extending face grooves at their mutually adjacent ends, that between
the mutually adjacent ends of the fitting pins there is arranged
a cross-coupling element with mobile coupling claws projecting axially
from both sides thereof and extending relatively radially movably
into the face grooves of the fitting pins, which face grooves are
aligned perpendicularly with respect to one another, that the two
fitting pins extend into fitting holes of an eccentric sleeve rotatable
relative to the fitting pins, which fitting holes are eccentric
to one another, and that the head part and the shank part are connected,
with the intermediate clamping of the coupling element and/or the
eccentric sleeve, by means of a clamping anchor extending with radial
clearance through holes in the shank part and in the cross-coupling
element and engaging a thread on the head part and supported against
an abutment in the area of the shank part.
The fitting holes, which are eccentric to one another, are advantageously
arranged such that the longitudinal axis of the fitting hole receiving
the fitting pin of the shank part is aligned with the axis of rotation
of the tool and that the longitudinal axis of the fitting hole receiving
the fitting pin of the head part is parallel and radially offset
with respect to the axis of rotation of the tool.
The cross-coupling element is advantageously constructed as an
annular piece with mobile pairs of claws axially projecting to both
sides thereof and angularly spaced at 90.degree. with respect to
one another. The eccentric movement is, during rotation of the eccentric
sleeve, converted into a radial sliding movement between the head
part and the shank part by the cross-coupling element. The converting
of the movement requires a certain freedom of play in the coupling
area and a slight tilting of the cross-coupling element relative
to the tool axis. In order to make this possible, the claw flanks
of the cross-coupling element are aligned not exactly parallel from
their root toward the tip but are inclined at an angle. Also, the
axially facing bearing surfaces on the annular piece are not flat
but form an obtuse conical surface.
The shank part has, according to a preferred development of the
invention, an axial hole stepped toward the side of a pin, in the
enlarged part of which stepped hole a head of the clamping anchor
is guided. Spring means, advantageously constructed as a set of
springs, are arranged between the oppositely lying shoulders of
the stepped hole and of the clamping-anchor head. The spring means
assure that the eccentric sleeve and the cross-coupling element
are clamped, when the clamping anchor is tightened, at a certain
force between the head part and the shank part of the tool and are
thus adjusted free of play, however, are still rotatable or rather
transversely movable relative to these parts. A spacer ring can
additionally be arranged between the clamping-anchor head and the
set of springs.
According to a further advantageous development of the invention,
the stepped hole is closed off by an end screw on the side of the
clamping anchor head. The inside of the stepped hole between the
clamping-anchor head and the end screw can be filled with a fill
piece preferably consisting of a heavy material, like lead. This
fill piece has, on the one hand, the function of assuring that the
clamping anchor will not rotate within the hole. Furthermore, the
fill piece is used to stiffen the shank part and to improve the
damping behavior.
A further preferred embodiment of the invention provides that an
axially facing end of the shank part, which end faces the spindle,
is connected to a coupling part which can be coupled to a tool spindle
by means of a fitting pin axially projecting beyond a flat surface
oriented perpendicular with respect to the axis of rotation of the
tool.
The clamping anchor and, if necessary, the fill piece, the end
screw and the coupling part have advantageously an axial cooling-medium
channel for supplying cooling-medium to the chip flute. An adjusting
wrench can be introduced through the cooling-medium channel to adjust
the clamping force of the clamping anchor.
In order to prevent cooling fluid from exiting the cooling-medium
channel, the clamping-anchor head can have a peripheral groove in
order to receive therein an elastic gasket ring resting against
the inner surface of the stepped hole. As an alternative, it is
possible for the gasket ring to be arranged between oppositely lying
faces of the end screw and the clamping-anchor head, with it being
supported advantageously in radial direction on an axially projecting
hollow pin formed on the clamping-anchor head. A sealing of the
cooling-medium channel between the shank part and the coupling part
is assured by an elastic gasket ring arranged between oppositely
lying faces of the shank part and the coupling part and supported
in radial direction on the end screw projecting axially beyond the
shank part.
In order to make the rotation of the eccentric sleeve easier, the
eccentric sleeve is advantageously provided with an outer multi-surface
section for the engagement of an adjusting wrench. The eccentric
sleeve has furthermore a scale ring at its end facing the shank
part or the head part, on which scale ring the path of adjustment
can be read.
In order to enable a coarse positioning, the cutting support is
fixedly and radially adjustably arranged, for example, by means
of a locking screw on the head part.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be discussed in greater detail hereinafter in
connection with two exemplary embodiments schematically illustrated
in the drawings, in which:
FIG. 1 is a partially cross-sectioned side view illustration of
a fine-turning boring bar;
FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG.
1;
FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG.
2; FIG. 4 is a cross-sectional view of a modified exemplary embodiment
of a fine-turning boring bar corresponding with FIG. 2.
DETAILED DESCRIPTION
The fine-turning tools illustrated in the drawings consist essentially
of a head part 10 a shank part 16 connected to the head part through
a cross-coupling element 12 and a clamping anchor 14 and an eccentric
sleeve 18 rotatable relative to the head part and the shank part.
A cutting support 20 carrying a throw-away insert 22 is radially
adjustable in the head part for the purpose of the coarse feeding
by means of a threaded pin 24 and is fixably arranged by means of
a clamping screw 26.
Each end of the eccentric sleeve 18 has a fitting hole 32 and 34
respectively facing the head part 10 and the shank part 16. The
fitting holes 32 and 34 are arranged eccentrically to one another,
with the longitudinal axis of the fitting hole 34 on the side of
the shank part being aligned with the axis of rotation of the tool
while the longitudinal axis of the fitting hole 32 on the side of
the head part is arranged eccentrically with respect to the axis
of rotation of the tool. Axially aligned cylindrical fitting pins
28 or 30 respectively formed on the head part 10 and on the shank
part 16 extend into the fitting holes 32 or 34 from opposite ends.
The fitting pins 28 30 have radially aligned face grooves 36 38
at their mutually opposing ends. Pairs of radially extending, mobile
claws 40 42 project axially toward opposite sides of the cross-coupling
element 12 and are received into the face grooves 36 38. As can
be seen particularly in FIG. 3 the mobile pairs of claws 40 42
are aligned perpendicularly to one another at the cross-coupling
element 12. In addition, the face grooves 36 38 are, in the mounted
state, aligned perpendicularly to one another at the two fitting
pins 28 30. The center hole 44 in the cross-coupling element 12
is designated for the passage of the clamping anchor 14.
The shank part 16 contains a continuous axially extending stepped
hole 46 into which the clamping anchor 14 with its head 48 and
threaded shank 50 can be introduced for the purpose of assembly.
The threaded shank 50 attached to the head 48 extends with clearance
through the wide part 46 of the stepped hole in the shank part 16
through the narrow part 56 of the stepped hole in the fitting pin
30 and the center hole 44 in the cross-coupling element and is screwed
into a tapped hole 58 in the fitting pin 28 of the head part 10.
Furthermore, the head 48 has for this purpose a hexagonal recess
60 into which a hexagonal wrench can be inserted from the exterior.
A set of springs 66 is arranged between a compensating plate 62
resting on the clamping-anchor head 48 and an annular shoulder 64
of the stepped hole 46. The set of springs 66 makes sure that the
tool parts 10 16 to be connected are clamped together without any
play, but that a turning of the eccentric sleeve 18 and a moving
of the cross-coupling element 12 relative to the head part 10 and
shank part 16 are still possible. The eccentric sleeve 18 is turned
when the shank part 16 is fixedly held by means of an adjusting
wrench engaging the peripheral hexagon 68. The cross-coupling element
12 has, besides the purpose of providing a turning coupling between
the shank part 16 and the head part 10 the purpose of converting,
during a turning of the eccentric sleeve 18 the eccentric movement
between the holes 32 and 34 into a sliding movement between the
head part 10 and the shank part 16. The path of movement relative
to a zero line 72 on the shank part can thereby be read on a scale
70 on the eccentric sleeve 18.
A central cooling-medium channel 80 passing through the boring
tool and terminating in a chip flute 78 assures a supplying of the
machining area with a cooling medium.
The fine-turning boring bar illustrated in FIGS. 1 to 3 has a shank
part 16 which is cylindrical over its entire length and the end
of which, which end is remote from the head part 10 can be clamped
in a tool chuck on a tool spindle. The open end of the shank part
16 is closed off by a fill piece 74 and an end screw 76 screwed
into an internal thread in the stepped hole 46. The parts 74 76
on the one hand, assure that the clamping anchor 14 will not rotate
within the hole and, on the other hand, the fill piece 74 consisting
of a heavy metal, like lead, is used to improve the damping characteristics
of the boring bar and to reinforce the shank part 16. The cooling-medium
channel 80 leading to the chip flute 78 is composed of holes in
the parts 76 74 14 10. An O-ring 54 arranged in a peripheral
groove 52 of the clamping-anchor head 48 assures a liquid-tight
guiding of the clamping-anchor head on the inner surface of the
enlarged part of the stepped hole 46 and thus a leakage-free sealing
of the cooling-medium channel 80 between the clamping-anchor head
48 and the chip flute 78.
The shank part 16 is, in the exemplary embodiment illustrated in
FIG. 4 constructed to include an enlarged diameter flange 81 at
its end remote from the head part 10 connected to a coupling part
83 the axially projecting fitting pin 84 of which, which fitting
pin is surrounded by an annular flat surface 82 can be clamped
in a corresponding fitting hole of a machine tool spindle (not illustrated)
or a modular intermediate piece by axially pressing the flat surface
82 against a corresponding flat surface surrounding the fitting
hole. The flange 81 and the coupling part 83 are connected by four
holding screws 86 extending into blind holes 88 in the coupling
part 83 and by two cylindrical pins (not illustrated), which act
as a lock against relative rotation, projecting in axial direction
beyond the face 90 of the shank part 16 and are received into corresponding
fitting holes in the coupling part 83.
An end screw 76', which is screwed into an internal thread 91 in
the stepped bore 46 and is clamped with an annular surface 92 thereof
against the face of the clamping-anchor head 48 in the shank part
16 facing the spindle, to secure the clamping anchor 14 against
automatically from turning, and serves with its part 93 projecting
in axial direction beyond the flange 81 as a guide 93 during a connecting
of the shank part 16 to the coupling part 83. The central cooling-medium
channel 80 formed by the holes in the coupling part 83 in the end
screw 76', in the clamping anchor 14 and in the head part 10 is
sealed by two O-rings 96 and 98 clamped against faces of the clamping-anchor
head 48 and the end screw 76' and faces the shank part 16 and the
coupling piece 84. The O-rings are respectively supported in radial
direction on an axially projecting hollow pin 100 formed on the
clamping-anchor head 48 and on the guide 93 of the end screw 76'.
An adjustment of the clamping anchor 14 to be carried out in order
to change the clamping force can be done with the help of an adjusting
wrench that can extend through the cooling-medium holes in the coupling
part 83 and in the end screw 76' and into the hexagonal recess 60
in the clamping-anchor head 48.
Compared with the boring bar with the cylindrical shank part illustrated
in FIGS. 1 to 3 the boring tool according to FIG. 4 has a greater
stiffness and is at the same time shorter. |