Machine tools abstract
The invention concerns a work carrier changeover device for machine
tools, with a work carrier transfer device for moving the work carrier
(16) between a machining station (15) and a tooling station (21).
The work carrier transfer device has a coupling element (25) rotatable
around a vertical axis and two opposing coupling points (26 27)
for the coupling of work carriers (16). The coupling element (25)
is pivotably mounted at free end section of a swivel arm (24) capable
of swivelling around a vertical axis.
Machine tools claims
1. Work carrier changeover device for machine tools, with a work
carrier transfer device for moving the work carrier (16) between
a machining station (15) and a tooling station (21), wherein the
work carrier transfer device has a coupling element (25) rotatable
around a vertical axis and with two opposing coupling points (26
27) for the coupling of work carriers (16), characterised in that
the coupling element (25) is pivotably mounted at the free end section
of a swivel arm (24) capable of swivelling around a vertical axis.
2. Work carrier changeover device according to claim 1 characterised
in that the swivel axis of the swivel arm (24) is offset to the
side of the access zone (17) of the machining station (15).
3. Work carrier changeover device according to claim 2 characterised
in that the access zone (17) is provided with a closable door assembly
(18), which may be controlled in particular automatically or electronically.
4. Work carrier changeover device according to any of the preceding
claims, characterised in that a crank mechanism (28) which may be
driven by the movement of the swivel arm (24) is provided to drive
the coupling element (25).
5. Work carrier changeover device according to any of claims 1
to 3 characterised in that an electrical or fluidic actuator is
provided for the coupling element (25) and may be controlled by
an electronic control unit in accordance with the movement of the
swivel arm (24).
6. Work carrier changeover device according to any of the preceding
claims, characterised in that the machining station (15) has a worktable
provided with means for the holding and locating of work carriers
(16).
7. Work carrier changeover device according to any of the preceding
claims, characterised in that the coupling element (25) and/or the
swivel arm (24) is or are provided with a vertical lifting device,
and that the coupling points (26 27) of the coupling element (25)
are formed by a vertical lift for coupling to the work carriers
(16) from below.
8. Work carrier changeover device according to any of the preceding
claims, characterised in that the coupling points (26 27) of the
coupling element (25) are provided with non-positive or positive
retaining means for releasable fixing of work carriers (16).
9. Work carrier changeover device according to any of the preceding
claims, characterised in that the tooling station (21) is designed
as an independent station, separate from the machine tool.
10. Work carrier changeover device according to claim 9 characterised
in that a swivel door assembly (31 32) is provided on a cabin wall
(22) forming an outer space in front of the access zone (17) to
the machining station (15) and, in a first operating position the
tooling station (21) engages in this outer space, and in a second
setting the tooling station (21) moves away from this outer space.
Machine tools description
[0001] The invention relates to a work carrier changeover device
for machine tools, with a work carrier transfer device for moving
the work carrier between a machining station and a tooling station,
wherein the work carrier transfer device has a coupling element
rotatable around a vertical axis and with two opposing coupling
points for the coupling of work carriers.
[0002] In a changeover device of this kind known from EP 0409085
B1 a coupling element for work carriers, capable of rotating through
180.degree., is located on the machine itself, while a linear work
carrier traversing station is also required to bring the work carriers,
each provided with workpieces, to the machining station. Besides
the poor accessibility to the working area due to the direct mounting
of the changeover device on the machine, the traversing station
takes tip a large amount of space. Subsequent attachment to a standard
machine is generally impossible. Attachment to the machine brings
about inadequate decoupling between machining station and setting-up
station so that there is a danger that, during the setting-up process,
i.e. during the loading of the work carrier with new workpieces
at the setting-up station, machining at the machining station is
adversely affected. A further drawback lies in the fact that, due
to the transfer by means of swivel and linear movements, the work
carrier changeover takes an unsatisfactory length of time.
[0003] Known from DE 19513827 A1 and DE 10020804 A1 are work carrier
changeover devices which are fully integrated in the machine and
which require no linear movements. In this case, subsequent attachment
to a standard machine would mean even greater expense, which would
make such attachment virtually impossible. In actual-time parallel
tooling, the integration of tooling station and machining station
means that vibrations and forces are transmitted to the machining
table, which has a negative effect on the accuracy of machining.
Automatic loading by means of a handling system is therefore even
more problematic. Another drawback is the poor accessibility to
the machining station due to the platen shuttle being rigidly attached
to the machine.
[0004] Finally, EP 1084794 A1 discloses a work carrier changeover
device with a handling system in which the work carrier is brought
from a pallet shelf unit to the machining station by a loading unit.
While this certainly leads to good decoupling of machining station
and tooling station, and provides good accessibility to the working
area, there is a very high space requirement together with an expensive
and cost-intensive design, while the work carrier changeover requires
a relatively large amount of time.
[0005] A problem of the present invention is to create a work carrier
changeover device which provides good decoupling between machining
station and tooling station and good accessibility to the machining
station, with a simple and cost-effective design which permits rapid
work carrier changeover and may easily be retrofitted to standard
machines.
[0006] This problem is solved according to the invention by providing
that the coupling element is pivotably mounted at the free end section
of a swivel arm capable of swivelling around a vertical axis.
[0007] The benefits of the solution according to the invention
are in particular that, because of the horizontally pivotable swivel
arm with rotatably mounted coupling element, only one mechanical
sub-assembly is required for feeding and changeover of the swivelling
work carrier and pallets. The coupling element is not attached rigidly
to the machine, but instead is mounted on a swivel arm which is
independent of the machine, thereby ensuring on the one hand easy
retrofitting capability and on the other hand good decoupling between
machine and tooling station. The working area of the machine tool
remains readily accessible, since the swivel arm may be swivelled
away. Due to the superposition of a swivelling and a rotary movement,
it is possible for the coupling element to traverse along a predetermined,
optimised, curved path. This makes possible a rapid changeover of
pallets, even where space is restricted.
[0008] The separate arrangement of the tooling station makes possible
automatic loading and unloading of pallets at this point using a
feed unit located at the setting-up station, for example a conveyor
belt.
[0009] Advantageous developments and improvements of the work carrier
changeover device specified in claim 1 are possible through the
measures set out in the subsidiary claims.
[0010] The swivel axis of the swivel arm is expediently offset
to the side of the access zone of the machining station, in order
to allow the best possible access to the machining area. The access
zone is provided with a closable door assembly, which in particular
may be controlled electronically, to allow passage of the swivel
arm for loading and unloading of work carriers.
[0011] In order to superimpose swivelling and rotary movements
of the swivel arm and coupling element a crank mechanism, which
may be driven by the movement of the swivel arm, is provided to
drive the coupling element. This may expediently be a so-called
four-bar mechanism. As an alternative to this, it is also possible
to provide an electrical or fluidic actuator for the coupling element,
which may be controlled by an electronic control unit to obtain
superimposed movement.
[0012] The machining station machine expediently has a worktable,
which is provided with means of accommodating and fixing work carriers.
[0013] The coupling element and/or the swivel arm are provided
with a vertical lifting device, wherein the coupling points of the
coupling element are formed by a vertical lift for coupling to the
work carriers from below. The coupling points of the coupling element
are preferably provided with non-positive or positive retaining
means for releasable fixing of work carriers, for example with an
hydraulic releasing and clamping system, to ensure safe changeover
of the work carriers and workpieces, some of which are very heavy.
With smaller work carriers, a positive means of retention may be
adequate.
[0014] The tooling station is designed as an independent station,
separate from the machine tool, thereby ensuring on the one hand
reliable decoupling, and on the other hand easy retrofitting of
machines.
[0015] The tooling station is expediently provided with a swivel
door assembly, which is located on a wall forming an outer space
in front of the access zone to the machining station, wherein in
a first operating position the tooling station is integrated in
this outer space, and in a second operating position the tooling
station is separated from this outer space. This enables the operator,
in the one operating position, to reach the tooling station too
from the access zone to the machining station. In the second operating
position, the swivel door assembly closes between the machining
station and the tooling station, so as to shield the working area
from water spray, enabling the pallet to be cleaned in the tooling
station for example using compressed air or spray.
[0016] An embodiment of the invention is shown in the drawing and
explained in detail in the description which follows. The drawing
shows as:
[0017] FIG. 1 a view from above of a machine tool provided with
a work carrier changeover device, during uncoupling of a work pallet
at the tooling station,
[0018] FIG. 2 the same arrangement, with the tooling station separated
from the working area by the swivel door assembly,
[0019] FIG. 3 the same arrangement during coupling of the coupling
element to a work carrier in the machining station,
[0020] FIG. 4 the same arrangement during movement of the swivel
arm and the coupling element from the machining station to the tooling
station,
[0021] FIG. 5 the same arrangement during the coupling of the coupling
element already provided at one end with the work carrier fetched
from the machining station, to a work carrier in the tooling station,
[0022] FIG. 6 the same arrangement with the coupling element rotated
through 180.degree., and
[0023] FIG. 7 the same arrangement during uncoupling at the tooling
station of the work carrier fetched from the machining station.
[0024] The machine tool shown in the Figures has a vertical spindle
nose 10 and is in gantry form. A slide 13 is able to traverse horizontally
on two side walls 11 12 of the machine column. The spindle nose
10 is able to traverse at right-angles and vertically to its front
side. Shown schematically in the rear area of the machine column
is a tool-change magazine 14. Between the side walls 11 12 and
below the spindle nose 10 a swivelling rotary table is pivotably
mounted around a horizontal axis for the direct accommodation of
work or to accommodate work carriers in the form of work pallets
16. The access zone 17 in front of the swivelling rotary table 15
forming the machining station may be closed by doors 18 which may
be slid sideways or upwards or hinged up. Located at the side of
the machine tool is a control console 19 which may be swivelled
in and out.
[0025] The depicted variant of the machine tools is only an example,
i.e. the work carrier changeover device or work pallet changeover
device 20 described below may in principle be mounted on any desired
machine tool to move work pallets 16 between a tooling station 21
outside the machine tool and the machining station of the machine
tool, which in the embodiment is the swivelling rotary table 15.
So, instead of a swivelling rotary table 15 any other work accommodation
designed for the fixing in place of work pallets may be provided.
This purpose may for example be served by an intrinsically known
hydraulic release and clamping system with "male" and
"female" contours. In the simplest case, a fixed worktable
may be provided.
[0026] The work carrier changeover device 20 is in the form of
a cubicle with a cubicle wall 22 which is attached or fitted to
or set up on the machine tool wall 23. Within the cubicle and cubicle
wall 22 a swivel arm 24 is capable of swivelling horizontally around
a vertical swivel axis. The swivel axis is here located to the side
of the access zone 17 to the machining station, so as not to impede
free access to the access zone 17. At the free end section of the
swivel arm 24 a coupling element 25 for coupling two work pallets
16 to opposing coupling points 26 27 is mounted so as to pivot
around a vertical axis. The drive for rotation of the coupling element
25 is effected via a crank mechanism 28 as a function of the rotation
of the swivel arm 24. A so-called four-bar mechanism may for example
be used for this purpose. By means of this crank mechanism 28 the
superposition of the swivel movement of the swivel arm 24 on the
rotation of the coupling element 25 may be set as to obtain an optimal
transfer of work pallets 16 between the tooling station 21 and the
swivelling rotary table 15. As an alternative to a crank mechanism
28 rotation of the coupling element 25 may also be electronically
controlled via an electrical or fluidic actuator.
[0027] To couple work pallets 16 to the coupling element 25 the
coupling points 26 27 are designed as mating projections which
engage in corresponding mating recesses 29. In each case this is
effected from below, for which purpose the coupling element 25 and/or
the swivel arm 24 are or is provided with a vertical lifting device,
not shown in detail. If the coupling points 26 or 27 are each inserted
from below into such a mating recess 29 in a work pallet 16 as a
positive fastening, a force-closed fixing may also be effected,
for example via an hydraulic release and clamping system. In the
case of smaller pallets, such a force-closed fixing may also be
dispensed with.
[0028] In the position according to FIG. 1 a work pallet 16 provided
with machined workpieces 30 is set down at the tooling station 21
by downwards movement of the coupling element 25 after the release
of any existing fastening. At the same time the work pallet 16 is
set down on a setting-up table, not illustrated and for example
in the form of a rotary table, of the tooling station 21. During
this process, workpieces arranged on a second work pallet 16 are
machined at the machining station, i.e. on the swivelling rotary
table 15 by tools on the spindle nose 10.
[0029] The cubicle wall 22 of the tooling or changeover cubicle
has two curved swivel doors 31 32 which close off the area of
the tooling cubicle facing away from the machine tool. To clean
work pallets 16 set up on the tooling station 21 and for loading,
the swivel doors 31 32 may as shown in FIG. 2 be so swivelled inwards
that they separate the tooling station 21 from the remainder of
the interior of the tooling cubicle. The tooling cubicle or changeover
cubicle is now shielded from spray water and the work pallet 16
may be cleaned by compressed air and/or spray guns. The work pallet
16 is then replaced by another with unmachined workpieces, or is
loaded with unmachined workpieces. During this process the swivel
doors 31 32 may remain in the shielding position shown in FIG.
2 and are then swung back again into the original position shown
in FIG. 1. Depending on the method of feeding new work pallets,
the swivel doors 31 32 may also be swung back into the original
position even beforehand.
[0030] After, before or during the changeover at the tooling station
21 the swivel arm now swivels towards the swivelling rotary table
15 as shown in FIG. 3 while the doors 18 at the access zone 17
of the machine tool open automatically. Raising of the coupling
element 25 results in coupling to the work pallet 16 located on
the swivelling rotary table 15. By means of this vertical lifting,
the work pallet 16 is also raised from the swivelling rotary table
15 following previous release of the fastening. This is effected
automatically, just like any additional fixing to the coupling element
25.
[0031] In accordance with FIG. 4 the work pallet 16 with machined
workpieces, which are not shown for simplicity, and which is coupled
to the swivel arm 24 and coupling element 25 respectively, moves
back. By suitable superposition of the swivel movement of the swivel
arm 24 and the rotary movement of the coupling element 25 it is
possible to set up an optimal movement of the work pallet 16 through
the access zone 17 to the tooling station 21 which is achieved
in the illustration of FIG. 5. There the coupling element 25 is
coupled to the work pallet 16 with unmachined workpieces which is
deposited at that point. After coupling in the manner described,
the coupling element 25 rotates through 180.degree. as shown in
FIG. 6. FIG. 7 shows the position at the end of this rotation. The
work pallet 16 with the machined workpieces is now placed on the
tooling station 21 by lowering and uncoupling, and the work pallet
16 with the unmachined workpieces which still remains on the coupling
element 25 is moved to the swivelling rotary table 15 in accordance
with FIG. 3 where it is uncoupled and set down, whereupon automatic
fixing or clamping to the swivelling rotary table 15 is effected.
[0032] In FIGS. 4 to 7 it may be seen that the swivelling rotary
table 15 is also provided with a rotary table 33. The latter is
optional. Also in the simplest case, a fixed worktable may be used
instead of a swivelling rotary table 15.
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