Machine tools abstract
Tool turret device for machine tools, comprising a turret head
bearing device, to which a turret head is attached for rotation
about an indexing axis, a turret head indexing device as well as
locking means for the turret head, the turret head indexing device
having an indexing disk similar to a Maltese cross, which is rotatable
about the indexing axis together with the turret head and has a
slot open at its circumference for each tool station of the turret
head, and a rotarily drivable driver with a driver finger for insertion
into the indexing disk slots, wherein for shortening the indexing
times and saving on separate locking means the driver has at least
two driver fingers arranged at equal distances from the driver axis
and the indexing disk slots are equipped at their free ends with
arc-shaped curves widening the slot width outwardly in such a manner
that angle of rotation regions, in which the driver secures the
indexing disk against any rotation, adjoin an angle of rotation
region of the driver, over which this turns the indexing disk.
Machine tools claims
I claim:
1. Tool turret device for machine tools, comprising a turret head
bearing device, a turret head having a plurality of tool stations
being attached to said bearing device for rotation about an indexing
axis, a turret head indexing device for rotating thus turret head
out of one indexing position, in which one of its tool stations
is in an operating position, into a different indexing position,
in which a different tool station is in an operating position, as
well as locking means for holding the turret head in its indexing
positions and for the rotary release of the turret head during indexing,
wherein the turret head indexing device has an indexing disk similar
to a Maltese cross and a driver, said indexing disk being rotatable
about the indexing axis together with the turret head, non-rotatably
connected to the turret head and having for each tool station of
the turret head a slot open at the circumference the indexing disk
and provided with two longitudinal flanks, said driver being drivable
for rotation about a drive axis parallel to the indexing axis and
bearing eccentrically to the drive axis at least two driver fingers
for insertion into an indexing disk slot for indexing the indexing
disk further and for removal from the indexing disk slot, said driver
fingers being arranged at equal radial distances from the driver
drive axis and at an angle of rotation distance from one another,
characterized in that the drive fingers are formed by rollers mounted
on the driver so as to be freely rotatable about axes parallel to
the driver drive axis and each driver finger has a locking roller
segment with a first outer diameter as well as an indexing roller
segment with a second, smaller outer diameter, the latter being
smaller than the transverse distance of the two longitudinal flanks
of the indexing disk slots from one another, and that a curve convex
towards a longitudinal center line of the relevant slot is associated
with each longitudinal flank of each of the indexing disk slots,
wherein the indexing roller segments are insertable into the indexing
disk slot and the locking roller segments are adapted to rest against
the convex curves, said curves being set back in relation to the
longitudinal flanks of the indexing disk slots and staggered in
the direction of the indexing axis, and wherein the slots, the curves
and the driver fingers are designed and arranged in such a manner
that, proceeding from a rest position of the driver, in which one
the turret head tool stations is in an operating position and the
locking roller segments of two driver fingers rest free of clearance
against the two adjacent curves of two adjacent indexing disk slot
the indexing roller segment of a first one of these two driver fingers
is insertable into a first one of these two indexing disk slots
due to rotation of the driver and the turret head is thereby rotatable
into its next indexing position, wherein this indexing roller segment
rests only against the leading longitudinal flank of this first
slot in the direction of movement of said segment, and that also
in this next indexing position the locking roller segment of the
first driver finger as well as the locking roller segment of another
driver finger rest free of clearance against one of the two aforementioned
curves and against the curve of the next indexing disk slot adjacent
this curve.
2. Device as defined in claim 1 characterized in that each of
the indexing disk slots widens towards the outside in the region
of its open end.
3. Device as defined in claim 1 characterized in that the curves
are designed such that the driver fingers are out of contact with
the curves during the rotation of the turret head.
4. Device as defined in claim 1 characterized in that the curves
are of a circular an arc-shaped design and of such a length and
arranged such that, proceeding from one of the rest positions of
the driver, the two driver fingers move along these two curves and
so as to rest against them over a first angle of rotation region
of the driver without turning the indexing disk, the turret head
is turned into its next indexing position by the first driver finger
engaging in the first indexing disk slot over a second angle of
rotation region of the driver following said first angle of rotation
region, and the first and another driver finger move along one of
these two curves as well as a curve of the next indexing disk slot
adjacent to said one curve and so as to rest against these curves
over a third angle of rotation region of the driver following said
second angle of rotation region without turning the indexing disk
so that the turret head is secured against rotation by the curves
and the driver fingers in the first and the third angle of rotation
regions.
5. Device as defined in claim 4 characterized in that the curves
are of such a length that at the transition from the first to the
second angle of rotation regions the driver finger moving out of
one of the two indexing disk slots clears the curve adjacent to
it.
6. Device as defined in claim 1 characterized in that the driver
has only two driver fingers.
7. Device as defined in claim 6 characterized in that the angle
of rotation distance of the driver fingers from one another is 180.degree..
8. Device as defined in claim 4 characterized in that the sum
of the three angle of rotation regions is 180.degree..
9. Device as defined claim 4 characterized in that the first and
the third angle of rotation regions are of the same size.
10. Device as defined in claim 8 characterized in that the second
angle of rotation region is at least 90.degree. and less than 160.degree..
11. Device as defined in claim 10 characterized in that the second
angle of rotation region is approximately 135.degree..
12. Device as defined in claim 10 characterized in that the second
angle of rotation region (D) is approximately 120.degree..
13. Device as defined in claim 1 characterized in that one of
the turret head and indexing disk rotatable about the indexing axis
is adapted to be pressed by a pressure medium piston against a stationary
part of the turret head bearing device.
14. Device as defined in claim 13 characterized in that the rotatable
part is the turret head.
15. Device as defined in claim 13 characterized that the pressure
medium piston is acted upon with pressure medium only on one side
in the sense of pressing the rotatable part against the stationary
part and at least one seal associated with the pressure medium piston
forms a return spring for the pressure medium piston operative during
pressure release.
16. Device as defined in claim 13 characterized a cam non-rotatably
coupled with the driver for controlling a pressure medium valve
in a pressure medium line leading to the pressure medium piston.
17. Device as defined in claim 1 characterized in that in the
rest position of the driver the driver drive axis extends between
two adjacent slots and the two facing curves of these two slots
are symmetrical to the driver drive axis.
18. Device as defined in claim 1 characterized in that the slots
are designed to be oriented radially in relation to the indexing
axis and each symmetrical to a central plane containing the indexing
axis.
19. Device as defined in claim 4 characterized in the one of the
turret head and indexing disk rotatable about the indexing axis
is adapted to be pressed by a pressure medium piston against a stationary
part of the turret head bearing device and in that a cam is non-rotatably
coupled with the driver for controlling a pressure medium valve
in a pressure medium line leading to the pressure medium piston,
and the cam is designed such that the pressure medium valve is reversible
in beginning and end sections of the first and third angle of rotation
regions respectively, in order to thus block the rotatable turret
head or indexing disk over the remaining sections of the first and
third angle of rotation regions.
20. Device as defined in claim 1 characterized in that the facing
curves of two adjacent indexing disk slots are formed by a disk-shaped
member common to both curves, the circumference of said member having
the shape of at least part of a circle.
21. Device as defined in claim 20 characterized in that the circumference
of the member is of an arc-shaped design at least in two oppositely
located regions.
22. Device as defined in claim 1 characterized by a driver drive
motor designed as an electrical geared motor or as a hydromotor.
23. Device as defined in claim 22 characterized that a switching
device controlled by the angle of rotation is associated with the
driver drive motor.
24. Device as defined in claim 1 characterized in that the longitudinal
flanks of the indexing disk slots extend parallel to tangents to
the inner ends of the curves.
Machine tools description
The invention relates to a tool turret device for machine tools,
in particular machine lathes, comprising a turret head bearing device,
to which a turret head having a plurality of tool stations is attached
for rotation about an indexing axis, a turret head indexing device
for rotating the turret head out of one indexing position, in which
one of its tool stations is in an operating position, into a different
indexing position, in which a different tool station is in an operating
position, as well as locking means for holding the turret head in
its indexing positions and for the rotary release of the turret
head during indexing, wherein the turret head indexing device has
an indexing disk similar to a Maltese cross, which is rotatable
about the indexing axis together with the turret head, is non-rotatably
connected to the turret head and has for each tool station of the
turret head a slot (where required in the form of a groove or the
like) open at its circumference (where required at the circumference
of an operative region of the indexing disk) and provided with two
longitudinal flanks, and a driver which is rotatable about a drive
axis parallel to the indexing axis and bears eccentrically to the
drive axis a driver finger (where required rod or the like) for
insertion into an indexing disk slot, for indexing the indexing
disk further and for removal from the indexing disk slot.
The purpose of a tool turret is to bring a plurality of tools,
which are held in the tool stations of the turret head, quickly
and precisely into an operating position one after the other in
a machine tool. Since, in general, workpieces cannot be machined
while the turret head is being indexed further (in order to bring
a different tool into an operating position), unproductive idle
times of this type have the effect, however, of increasing costs
with respect to the workpieces to be produced, it is required of
the producers of machine tools to shorten these idle times more
and more.
In known tool turret devices, one has to differentiate between
two functions which are independent of one another with respect
to their performance: On the one hand, the locking or unlocking
of the turret head in defined indexing positions, in each of which
a tool of the turret head is normally located in the operating position,
the locking of the turret head serving the purpose of preventing
any undesired turning of the turret head, and, on the other hand,
the rotating or indexing of the turret head into the next or one
of the other indexing positions in order to bring a different tool
into the operating position.
In order to lock or unlock the turret head, index bolts and the
like insertable into corresponding bores have been used; these do,
however, have the disadvantage that they cannot lock the turret
head free of clearance on account of the required clearance of motion;
moreover, they necessitate complicated mechanical actuating mechanisms
which are subject to considerable wear and tear and normally allow
only one direction of rotation of the turret head. Other known locking
devices work with so-called HIRTH-type tooth systems (rings with
toothed surfaces which engage in one another with their teeth in
the locked state); HIRTH-type tooth systems comprising two toothed
rings, of which one is stationary and the other connected to the
turret head, necessitate an axial displacement of the turret head
for locking or unlocking which makes them unsuitable for quick turret
indexings on account of the considerable mass of a turret head equipped
with tools. Three-part HIRTH-type tooth systems comprising three
toothed rings, of which one is displaceable in the direction of
the turret head indexing axis in order to be able to bring it into
engagement with a toothed ring provided on the turret head and,
at the same time, with a stationary toothed ring, are expensive
to produce and assemble since the precision of the locking of the
turret head in its indexing positions is dependent on the exactness
of the tooth engagement. Moreover, both types of HIRTH-type tooth
systems make actuating devices for an axial displacement of the
turret head or one of the three toothed rings necessary.
For the turning, i.e. the indexing of the turret head, electrical
or hydraulic positioning drives are used in known tool turret devices.
These drives must be highly dynamic when a fast indexing and an
exact positioning of the turret head are required and they are,
therefore, expensive; furthermore, it is known to turn, i.e. index,
the turret head by means of a Maltese cross transmission. In both
cases, one of the devices explained in the above for locking or
unlocking the turret head is, however, added in the known tool turret
devices since the known, specified rotary drives are not able to
hold the turret head exactly in its indexing positions--in this
connection, the high forces and torques, which can occur when work
is carried out at the turret head with a tool borne by the turret
head, should not be left out of consideration.
The object underlying the invention is to create a tool turret
device which may be produced inexpensively but at the same time
makes short idle times possible, i.e. short times for the unlocking,
indexing and locking of the turret head.
Proceeding from a known tool turret device of the type mentioned
at the outset, this object may be accomplished in accordance with
the invention in that the driver is provided with at least two driver
fingers which are arranged at equal radial distances from the driver
drive axis and at an angle of rotation distance from one another,
and that a curve of the indexing disk convex towards a longitudinal
center line of the relevant slot is associated with each longitudinal
flank of each of the indexing disk slots for resting against a driver
finger, wherein the slots, the curves and the driver fingers are
designed and arranged in such a manner that, proceeding from a rest
position of the driver, in which one of the turret head tool stations
is in an operating position and the two driver fingers rest free
of clearance against the two adjacent curves of two adjacent indexing
disk slots, a first one of the two driver fingers can be inserted
into a first one of these two indexing disk slots due to rotation
of the driver, the turret head is thereby and due to further rotation
of the driver rotatable into its next indexing position and, in
the latter, this first driver finger as well as another driver finger
rest free of clearance against one of the two aforementioned curves
as well as against the curve of the next indexing disk slot adjacent
this one curve.
The inventive construction is therefore characterized in that on
both sides of that angle of rotation region of the driver, over
which the latter turns the indexing disk, driver positions are located,
in which the indexing disk is locked, i.e. secured against rotation,
by two driver fingers and held exactly in an indexing position which
corresponds to an operating position of the turret head. In this
respect, the indexing disk slots and the curves associated with
them must, of course, be dimensioned such that one of the two driver
fingers releases the indexing disk when the other driver finger
begins to turn the indexing disk.
It has already been pointed out that the slots of the indexing
disk can also have the shape of grooves but also the shape of other
detent-like channels of the indexing disk, between which the driver
fingers can engage and with which the latter can interact. The slots
or the like need also not necessarily be straight or even extend
radially to the indexing axis although this is recommended. The
driver fingers also need not be elongated elements which are held
by the driver only at their one end--the driver could, for example,
have the shape of two disks which are arranged in axial spaced relation
to one another and between which the driver fingers extend in the
form of rods so that the latter interact with the indexing disk
with central regions. It is clear, particularly from the example,
in which the driver fingers engage in grooves of the indexing disk,
that these grooves need not extend as far as the outer circumference
of the indexing disk (the latter considered in a front view) and
that a drum-shaped element can also replace an indexing disk.
A tool turret device designed according to the invention has, in
principle, the following advantages: The turret head indexing device
forms at the same time the means for the precise locking of the
turret head in its indexing positions and for the unlocking of the
turret head so that not only can special locking means be omitted
but also an additional actuating device for these locking means.
A further, essential advantage consists in the fact that the transitions
between unlocking, turning and locking of the turret head can take
place completely harmonically and without any delay in time which
contributes to achieving quicker turret indexing procedures in the
same way as the fact that unproductive idle times, as are necessary
in the state of the art for the unlocking and locking of the turret
head and the signal transmission between machine tool and machine
tool control connected with it, can be avoided. When comparing the
inventive construction with the state of the art the fact should
also not be left out of consideration that in the known constructions,
if short turret indexing times are required, the angle of rotation
positioning of the turret head effected by the turret head indexing
drive can never be exact, particularly not in the case where the
turret head has a considerable imbalance due to corresponding tool
equipment, and so the turret head will not be turned or returned
finally into the selected indexing position until it is locked,
e.g. by a HIRTH-type tooth system.
The invention therefore results not only in a considerable simplification
of the construction of a tool turret device and, therefore, in considerable
cost savings, but also in a clear reduction of the time intervals
necessary altogether for indexing the turret head further.
The indexing disk slots could extend as far as the indexing disk
circumference with a constant width if the circumference is not
intended to be circular in design and, consequently, the curves
can form regions which project in radial direction beyond the outer
ends of the indexing disk slots. However, embodiments are preferred,
in which each of the indexing disk slots widens towards the outside
in the region of its open end in order to thus create the possibility
of giving the indexing disk a circular shape without the indexing
disk slots making any turning of the driver out of one of its rest
positions impossible.
For a clearance-free locking of the turret head in its indexing
positions it is merely necessary for two driver fingers to rest
free of clearance against two of the curves of the indexing disk
in the rest positions of the driver corresponding to the indexing
positions of the turret head; this may be achieved, for example,
with curves which correspond to part of an ellipse or a parabola
and thus ensure that the locking of the indexing disk and, with
it, the turret head takes place jerk-free when the driver is turned
into one of its rest positions. So that no complicated control for
the angle of rotation positions is required for the driver or rather
its rotary drive, the curves are, however, of an arc-shaped design
in preferred embodiments of the invention, at least over their effective
regions, namely such that the arcs of the two facing curves of two
adjacent indexing disk slots extend concentrically to the driver
drive axis when the turret head and, with it, the indexing disk
takes up one of its or rather their indexing positions. Such an
embodiment of the inventive tool turret device is therefore characterized
by the fact that the curves are of an arc-shaped design and of such
a length and arranged such that, proceeding from one of the rest
positions of the driver, the two driver fingers move along these
two curves and so as to rest against them over a first angle of
rotation region of the driver without turning the indexing disk,
the turret head is turned into its next indexing position by the
first driver finger engaging in the first indexing disk slot over
a second angle of rotation region of the driver following the first
angle of rotation region, and the first and another driver finger
move along one of these two curves as well as a curve of the next
indexing disk slot adjacent to the latter curve and so as to rest
against these curves over a third angle of rotation region of the
driver following the second angle of rotation region without turning
the indexing disk so that the turret head is secured against rotation
by the curves and the driver fingers in the first and the third
angle of rotation regions. The special features of such a construction
are, therefore, that angle of rotation regions of the driver, in
which, on the one hand, a rotary movement of the driver does not
result in a rotary movement of the indexing disk and, on the other
hand, the latter is locked, i.e. secured against rotation, by the
driver fingers and is thus held precisely in an indexing position
together with the turret head, adjoin that angle of rotation region
of the driver, over which the latter turns the indexing disk and,
with it, the turret head, on both sides. For a precise positioning
of the turret head in its indexing positions it is not, then, important
whether the rotary drive for the driver is able to stop this exactly
in predetermined angle of rotation positions since the driver can
be stopped anywhere in the third angle of rotation region after
passing through the second angle of rotation region since the driver
locks the indexing disk and, with it, the turret head precisely
in one of the indexing positions in any angle of rotation position
located within this third angle of rotation region. The motor effecting
the rotary drive of the driver does not, therefore, require any
complicated position control since any electrical geared motor with
a brake or hydromotor is able to stop the driver within the third
angle of rotation region.
In a preferred embodiment of the inventive tool turret device,
the driver has only two driver fingers. As is clearly apparent when
viewing the attached illustrations of a particularly advantageous
embodiment of the inventive tool turret device, a construction,
in which the driver has only two driver fingere, does represent
the simplest realization of the invention but embodiments are, however,
conceivable, in which the driver has more than two, e.g. three,
driver fingers--depending on the number of the tool stations and,
therefore, of the indexing positions of the turret head, the configuration
of the indexing disk slots, the position of the driver drive axis
relative to the indexing axis and the size of the radial distance
of the driver fingers from the driver drive axis and the angle of
rotation distance of the driver fingers from one another, the number
of driver fingers can vary.
The specified curves can be worked directly onto the indexing disk,
in particular by milling. For reasons of manufacture it can, however,
also be advantageous when the curves are formed by separate parts
secured to the indexing disk since these parts can be easily and
inexpensively manufactured very precisely; on the other hand, separate
parts of this type require special measures in order to be able
to secure them on the indexing disk in an exactly positioned manner.
As already mentioned, the driver fingers could be simple rods,
pins and the like but an indexing device which runs more easily
and quietly with low wear and tear and a more precise cycle of movement
results when the driver fingers are formed by rollers mounted on
the driver so as to be freely rotatable.
To avoid jerks and vibrations occurring when the turret head is
indexed further, embodiments are preferred, in which the width of
the regions of the slots effective for further indexing corresponds
to the diameter of the driver fingers so that the latter run in
the slots without transverse clearance.
To achieve an impact-free and harmonic cycle of movement of the
indexing device, it is recommended that the construction be designed
such that--for the driver fingers and seen in the direction of the
indexing axis--the curves merge continuously into the functional
regions of the longitudinal flanks of the indexing disk slots, with
it being particularly advantageous when--again with respect to a
driver finger--the longitudinal flanks of the indexing disk slots
form tangents to the radially inner curve ends.
It is completely adequate per se when the turret head can be positioned
and precisely locked in its various indexing positions by the inventive
indexing device; with a view to the fact that during use of tools
borne by the turret head quite considerable machining forces can
act on the turret head, the stability of the inventive tool turret
device can, however, be increased even further when one of the parts
rotatable about: the indexing axis, namely, and in particular, the
turret head, can be pressed preferably by a piston acted upon in
a controlled manner by pressure medium against a stationary part
of the turret head bearing device, in particular against a housing
of this bearing device, namely when the turret head has reached
its desired indexing position. The stroke of this pressure medium
piston can be minimal and so hardly any pressure medium, such as,
for example, hydraulic oil, need flow for blocking and releasing
the turret head and, consequently, only very little time is required
for these procedures. This principle can be realized in a particularly
simple manner when the pressure medium piston is acted upon with
pressure medium only on one side (in the sense of pressing the rotatable
part against the stationary part) and at least one seal associated
with the pressure medium piston forms a return spring for the pressure
medium piston which is operative during pressure release since,
in this case, a controlled supply of pressure medium to the other
side of the piston can be dispensed with as well as a separate return
spring for the pressure medium piston.
The manner in which the piston is acted upon with pressure medium
can also be controlled in a simple way when a cam is provided which
is non-rotatably coupled with the driver and controls a pressure
medium valve in a pressure medium line leading to the pressure medium
piston.
As already mentioned, it is not of importance in preferred embodiments
of the inventive indexing device for the driver to be stopped within
the first or third angle of rotation region in a specific angle
of rotation position; this circumstance makes it possible to avoid
unproductive idle times for the blocking or releasing of the turret
head with the aid of the specified pressure medium piston, namely
in that the specified cam is designed such that the pressure medium
valve is reversed in the beginning and end sections of the first
or third angle of rotation region in order to thus block the turret
head over the remaining sections of the first and third angle of
rotation regions.
Additional, advantageous developments of the inventive tool turret
device result from the attached claims and/or from the following
description and the attached drawings of two particularly advantageous
embodiments; in the drawings:
FIG. 1 is a longitudinal section through the first embodiment of
the inventive tool turret device, the turret head of which has,
for example, eight tool stations and, therefore, eight indexing
positions, FIG. 1 showing the tool turret device in a state it reaches
after half of the procedure of indexing the turret head further
from one of its indexing positions into the next indexing position
has taken place;
FIG. 2 shows the greatest part of the indexing disk as well as
the driver of the first embodiment equipped with two driver fingers,
seen in the direction of the indexing axis, FIG. 2 showing the state,
in which the indexing disk takes up an angle of rotation position
corresponding to an indexing position of the turret head (additional
positions of the driver fingers which these can take up without
the indexing disk being turned are indicated by dash-dot lines);
FIG. 3 is a section according to line 3--3 in FIG. 2;
FIG. 4 is a front view of the driver of the first embodiment, wherein
to explain the operating cycle the three aforementioned angle of
rotation regions of the driver have been illustrated in the case
of eight tool stations of the turret head and, moreover, the cam
which serves to control the securing of the turret head has been
indicated;
FIG. 5 shows a longitudinal section through part of the second
embodiment of the inventive tool turret device, FIG. 5 corresponding
to a section from FIG. 1 and containing an illustration corresponding
to FIG. 3; and
FIG. 6 is an illustration of the second embodiment corresponding
to FIG. 2.
FIG. 1 shows a tool turret bearing device in the form of a housing
10 with a housing body 12 and a housing cover 14 whereby this housing
can be attached by means of screws 16 for example, to a tool carrier
slide of a machine tool which is not illustrated. The illustrated,
inventive tool turret device includes, in addition, a turret head
18 which is provided at its circumference with eight tool stations
20 arranged at equal distances, each of which can be equipped with
an interchangeable tool holder. FIG. 1 shows two of these tool stations,
one of which is equipped with a tool holder 22 bearing a turning
tool 24 and the other with a tool holder 26 bearing a drill 28 (since
tool turrets for rotarily drivable tools are known, the tool holder
26 and the tool station 20 accommodating it could also be designed
such that the drill 28 can be used as a driven tool). The turret
head 18 is secured to the one end of a turret indexing shaft 30
which is mounted for rotation in the housing body 12 by means of
bearings 32 so that the indexing shaft 30 and, with it, the turret
head 18 can be turned about an indexing axis 34. The other, right-hand
end of the indexing shaft 30 according to FIG. 1 bears an indexing
disk 36 the construction and configuration of which will be explained
in greater detail on the basis of FIG. 2.
The indexing disk 36 has a circular disk body 38 concentric to
the indexing axis 34 and having a number of slots 40 corresponding
to the number of tool stations 20 of the turret head 18. These slots
40 are arranged at equal angle of rotation distances from one another
and have, in the illustrated embodiment, the shape of grooves which
are worked into the disk body 38 from the one end face thereof.
In accordance with the invention, each of the slots 40 is designed
to be in mirror symmetry to a central plane 42 which includes the
indexing axis 34 and represents a diameter plane of the disk body
38. In accordance with an additional feature of the invention, each
of the slots 40 comprises two regions, namely an inner, first region
located in radial direction inside a line 44 extending at right
angles to the associated central plane 42 and an outer, second region
located outside the line 44 and, if a rounding which is provided
at the radially inner slot end and has no function is disregarded,
the side walls 40a of the inner slot region extend parallel to one
another whereas the side walls of the outer slot region are defined
by curves 42b, the configuration of which will be explained in greater
detail at a later stage.
A positioning disk 48 is secured on the disk body 38 between respective
adjacent slots 40 namely by means of screws 50 (cf. in particular,
FIG. 3), and in accordance with the invention each of these positioning
disks has the shape of a section of a flat circular-cylindrical
body with a circular-cylindrical peripheral surface 48a. As shown
in FIGS. 2 and 3 the curves 42b are formed by parts of these peripheral
surfaces 48a and project (in a front view of the indexing disk 36)
outside the line 44 somewhat beyond the actual side walls 40a of
the slots 40 worked into the disk body 38 namely in the direction
towards the central plane 42 belonging to the relevant slot, as
FIG. 3 clearly shows. Since the exact position of the positioning
disks 48 on the disk body 38 is of decisive importance for the exactness
of the positioning of the turret head in its various indexing positions,
a set pin 52 which engages in bores in the positioning disk and
the disk body 38 is provided for each positioning disk.
The additional construction of the tool turret device will now
be described in the following on the basis of FIG. 1.
A driver 58 serving to turn the indexing disk 36 is mounted in
the housing cover 14 by means of two bearings 56 so as to be rotatable
about a driver drive axis 60; this driver can be driven by a motor
62 attached to the housing cover 14 and is for this purpose non-rotatably
connected to a motor shaft 64.
A switching device 66 is seated on the motor 62 for switching the
motor 62 on and off. This is preferably an electrical switching
device which is able to stop the motor shaft 64 at least approximately
in desired angular positions.
As shown particularly clearly by FIGS. 2 and 3 the driver 58 is
provided on its end face facing the indexing disk 36 with two driver
fingers 68 and 70 each of which consists of a hinge pin 72 secured
in the driver 58 and a cylindrical roller 74 freely rotatable on
this pin. In the illustrated embodiment, the axes 68a and 70a of
the two driver fingers 68 and 70 which are arranged at equal distances
from the drive axis 60 are located opposite one another in relation
to the drive axis 60 i.e. in a diameter plane of the driver 58
so that the angle of rotation distance between the two driver fingers
is 180.degree..
In accordance with the invention, the center of the circular-cylindrical
peripheral surface 48a of that positioning disk 48 which is associated
with the tool station 20 of the turret head 18 located in an operating
position, is located on the driver drive axis 60 in each indexing
position of the turret head 13 (cf. FIG. 2).
According to a further feature of the invention, the distance of
the axes 68a and 70a of the driver fingers 68 and 70 from the driver
drive axis 60 is coordinated with the diameter of the driver fingers,
i.e. the diameter of the rollers 74 and the distance between the
facing curves 42b of two adjacent slots 40 in the illustrated preferred
embodiment, therefore, with the diameter of the circular-cylindrical
peripheral surface 48a of the positioning disks 48 such that the
driver fingers rest against these curves 42b free of clearance;
in the illustrated preferred embodiment the rollers 74 therefore
run along the curves 42b free of clearance.
Furthermore, it is advantageous when the width of the slots 40
inside the line 44 i.e. the distance of the side walls 40a from
one another, is equal to the diameter of the driver fingers, in
the particular case of the rollers 74 or is only slightly larger
than this diameter.
In accordance with a further feature of the invention, a cam 78
is formed on the circumference of the driver 58 (cf. FIGS. 3 and
4) and this serves to control a valve 80 which is accommodated in
the housing cover 14 and the function of which will be explained
at a later stage.
As is apparent from FIG. 1 the rearward end face of the turret
head 18 is located directly opposite a front end face of the housing
body 12. Furthermore, the housing body 12 accommodates a ring-shaped
pressure medium piston 82 comprising the indexing shaft 30 and forms
for this piston with a stepped bore a pressure medium chamber 84
into which a pressure medium channel 86 coming from the valve 80
opens. In accordance with the invention, the pressure medium piston
82 is located directly opposite the indexing disk 36 in the illustrated
embodiment the end face of the disk body 38 facing away from the
positioning disks 48 and the pressure medium chamber 84 is located
on the side of the pressure medium piston 82 facing away from the
indexing disk 36. In accordance with the invention, two sealing
rings 88 and 90 held by the pressure medium piston 82 and/or by
the housing body 12 serve to seal the pressure medium chamber 84.
These sealing rings are elastically deformable in axial direction
in such a manner that they can bring about a resetting of the pressure
medium piston 82 (to the left according to FIG. 1) once this has
been pressed against the indexing disk 36 due to pressure acting
on its left side according to FIG. 1 and, subsequently, the pressure
medium chamber 84 has again been made pressureless.
In accordance with an additional feature of the invention, the
turret head 18 during indexing, slides on the end face of the housing
body 12 facing the turret head or in this state of the tool turret
device only a very slight gap is present between turret head and
housing body. In order to press the turret head 18 against the housing
body 12 and thus clamp it against a stationary part, a very slight
movement of the pressure medium piston 82 is therefore adequate
and so, for this purpose, practically no pressure medium has to
flow in the pressure medium channel 86.
Pressure medium, in particular hydraulic oil, can be supplied to
the pressure medium channel 86 via the valve 80 and a pressure medium
channel 92 formed in the housing cover 14 while a pressure medium
channel 94 serves to relieve pressure in the pressure medium chamber
84.
Reference should also be made to the fact that a customary axial
clearance of the bearings 32 holding the indexing shaft 30 is completely
adequate to clamp the turret head 18 on the housing body 12 with
the aid of the pressure medium piston 82.
The driver fingers 68 70 of the illustrated embodiment are, of
course, designed to be of such a length that they can interact not
only with the positioning disks 48 but also with the side walls
40a of the slots 40 formed in the disk body 38.
Finally, FIG. 1 shows an intermediate ring 100 due to which it
can be ensured, despite the formation of the pressure medium chamber
84 that the pressure medium piston 82 carries out only a very minimal
stroke, the size of which can be determined by adjustment of the
intermediate ring 100 for clamping the turret head 18 in position.
The functioning of the inventive turret head indexing device and
the cycle of movement during the further indexing of the turret
head will now be described in the following in greater detail on
the basis, in particular, of FIGS. 2 and 4. In this respect, this
description is based on the illustrated embodiment with eight tool
stations of the turret head; the alterations in dimensions applicable
for a different number of tool stations will, however, result for
the person skilled in the art automatically.
The various positions of the driver fingers 68 and 70 illustrated
by solid and dash-dot lines have been designated in FIGS. 2 and
4 by corresponding reference numerals, namely 68', 68 68"
or 70', 70 70". Moreover, several angle of rotation regions
of the driver 58 have been indicated in FIG. 4 with A, B, C and
D; with the illustrated preferred embodiment with eight stations
the angle of rotation region C is 45.degree. and the angle of rotation
region D 135.degree., the sum of C and D is, therefore, 180.degree.;
moreover, the sum (A+2B) is 45.degree.. In a turret head with only
6 equidistant tool stations, the angle of rotation region D would
preferably be 120.degree..
It is now to be assumed that during a preceding indexing procedure
the motor 62 has stopped the driver 58 in that angle of rotation
position, in which its driver fingers 68 and 70 take up the angle
of rotation positions illustrated in FIGS. 2 and 4 by solid lines.
Half a revolution of the driver 58 i.e. a rotation through approximately
180.degree., leads to the turret head 18 being rotated further from
one indexing position into one of the two indexing positions adjacent
to this indexing position--the turret head may be turned by the
inventive indexing device in both directions of rotation since the
indexing device is, in this respect, designed to be completely symmetrical.
Within the angle of rotation region C, i.e. between the positions
68' and 68" or 70' and 70", the driver fingers 68 70
move along the curves 42b without turning the indexing disk 36 and,
with it, the turret head 18; on the contrary, the latter is locked
in its respective indexing position over the entire angle of rotation
region C. If it is assumed that the driver 58 is turned in the counterclockwise
direction according to FIGS. 2 and 4 the driver finger 68 lifts
away from the positioning disk 48 at the beginning of the angle
of rotation region D and runs along the side wall 40a of the respective
slot 40 adjoining the positioning disk circumference; since the
driver finger 70 runs out of the slot 40 associated with it and
clears the adjacent curve 42b when the driver finger 68 leaves the
positioning disk 48 the rotation of the indexing disk 36 and, with
it, of the turret head 18 can begin at this moment. Whilst the driver
is passing through the angle of rotation region D, the turret head
18 is turned further through the angular distance between two adjacent
tool stations, with eight tool stations through 45.degree.. At the
end of the angle of rotation region D, i.e. when an angle of rotation
region C again begins, the driver finger 68 passes from one of the
side walls 40a onto the peripheral surface 48a of the next positioning
disk 48 and, at the same time, the driver finger 70 enters the
next-but-one slot 40 and likewise contacts the next positioning
disk 48. Since the rotary movement of the turret head 18 is terminated
after passing through the angle of rotation region D, it is unimportant
whether the driver 58 is turned exactly through 180.degree. from
one indexing position into a next indexing position for the purpose
of indexing the turret head since it is only important, as will
be shown in the following, for the driver 58 to be stopped within
the angle of rotation region A so that the switching device 66 controlling
the starting and stopping of the motor 62 need not be equipped for
an exact switching with respect to the angle of rotation.
The cam 78 controlling the valve 80 and, with it, the clamping
of the turret head 18 is designed in accordance with the invention
such that the valve 80 is reversed at the ends of the angle of rotation
region A, namely such that at the beginning of the procedure of
indexing the turret head further while the driver 58 is passing
through the angle of rotation region B the pressure medium chamber
84 acted upon with pressure oil over the angle of rotation region
A is made pressureless whereas, after the turret head has been turned,
namely after the driver has passed through the angle of rotation
regions D and B, the pressure medium piston 82 is again acted upon
with pressure medium and the turret head 18 is clamped on the housing
10--the short time span required for passing through the angle of
rotation region B is sufficient to release the clamping of the turret
head 18. The turret head can thus be indexed further in both directions
of rotation.
Whereas, in the illustrated first embodiment, the driver 58 must
be stopped within the angle of rotation region A, the larger angle
of rotation region C would be available for stopping the driver
in a tool turret device of the type without clamping of the turret
head.
It is essential that the one driver finger releases one of the
curves 42b (because the latter then ends) when the other driver
finger has reached an angle of rotation position, in which it begins
to turn the indexing disk 36.
The parts of the second embodiment illustrated in FIGS. 5 and 6
will be essentially described in the following only insofar as the
second embodiment differs from the first embodiment, and in FIGS.
5 and 6 the same reference numbers as in FIGS. 1-3 have been used
for those parts of the second embodiment which represent equivalents
of parts of the first embodiment, but with a prime sign added.
In the second embodiment, an indexing disk 36' is again provided
on the turret indexing shaft 30' mounted in a housing body 12' for
rotation about an indexing axis 34'. This indexing disk 36' has
for each indexing position of the turret head an indexing disk slot
40' which is open at its edge and designed as a groove, the functional
region of which is formed by two longitudinal flanks 40a' parallel
to one another and which widens towards the outside in its radially
outer region. At the right-hand end face of the indexing disk 36'
according to FIG. 5 positioning members 48' have been formed by
milling. The number of these positioning members corresponds to
the number of slots 40', each is located with respect to the angle
of rotation centrally between two slots 40' and each forms two curves
42b', the two curves 42b' of each positioning member 48' forming
parts of the cylindrical outer surface of a circular cylinder, the
axis 60" which extends parallel to the indexing axis 34' and
is located with respect to the angle of rotation exactly in the
center between the central planes 42' of the two adjacent slots
40'.
A driver 58' which is mounted for rotation about a driver drive
axis 60' and can be rotarily driven by means of a toothed drive
means 62' is again provided with two driver fingers 68' and 70'
offset in relation to one another through 180.degree. with respect
to the angle of rotation. Each of these driver fingers has a hinge
pin 72' which is secured in the driver 58' and on which a roller
74' designed as a stepped cylinder is mounted for rotation. This
roller forms a locking roller segment 74b' and an indexing roller
segment 74a', the diameter of which is smaller than that of the
locking roller segment 74b'. As is apparent, in particular, from
FIG. 6 the indexing roller segments 74a' interact with the longitudinal
flanks 40a' of the slots 40', the locking roller segments 74b' with
the curves 42b' of the positioning members 48'.
As is likewise apparent from FIG. 6 the drive axis 60' of the
driver 58' coincides with the axis 60" of the effective positioning
member 48' when the turret head is in one of its indexing positions
and the driver is in one of its two rest positions.
In the second embodiment according to FIGS. 5 and 6 the slots
40' and the curves 42b' are also designed and arranged such that
when one of the two driver fingers begins to turn the indexing disk
36' the other driver finger releases the indexing disk. Moreover,
the procedures of locking the indexing disk 36' and indexing the
indexing disk merge harmonically and jolt-free into one another
because the longitudinal flanks 40a' of the slots 40' and the curves
42b' of the positioning members 48' are of such a length and arranged
relative to one another such that for the rollers 74' of the driver
58' the curves 42b' merge continuously into the longitudinal flanks
40a' and the latter form tangents to the radially inner ends of
the curves 42b' (on account of the differing diameters of indexing
roller segment 74a' and locking roller segment 74b' with the curves
42b' offset transversely in relation to the longitudinal flanks
40a). The second embodiment also makes it clearly apparent that
the gaps between the curves effecting the locking need not be of
the same size as the width of the slots effecting the indexing.
The invention is, therefore, to be seen fundamentally in the following:
Tool turret device for machine tools, comprising a turret head bearing
device, to which a turret head is attached for rotation about an
indexing axis, a turret head indexing device as well as locking
means for the turret head, the turret head indexing device having
an indexing disk similar to a Maltese cross, which is rotatable
together with the turret head about the indexing axis and has a
slot open at its circumference for each tool station of the turret
head, and a rotarily drivable driver with a driver finger for insertion
into the indexing disk slots, wherein for shortening the indexing
times and saving on separate locking means the driver has at least
two driver fingers arranged at equal distances from the driver axis
and curves are associated with the indexing disk slots in the region
of their ends in such a manner that adjoining one angle of rotation
region of the driver, over which this turns the indexing disk, are
second angle of rotation regions, in which the driver secures the
indexing disk against any rotation, namely at least over part of
these second angle of rotation regions. |