U.S. patent application number 12/134599 was filed with the patent office on 2008-12-18 for device for conveying tablets.
This patent application is currently assigned to UHLMANN PAC-SYSTEME. Invention is credited to Rolf Armbruster, Bernd Geiselhardt, Ralf Heim, Wolfgang Krahl, Michael Kronawitter, Joachim Noe.
Application Number | 20080307757 12/134599 |
Document ID | / |
Family ID | 38617927 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080307757 |
Kind Code |
A1 |
Heim; Ralf ; et al. |
December 18, 2008 |
Device for Conveying Tablets
Abstract
A device for conveying tablets has a lower part, an upper part
with at least one guide channel for holding and conveying the
tablets, and several elastic elements, arranged a certain distance
apart, on each of which at least one piezoelectric vibratory
element is mounted, wherein the elastic elements are arranged
between the upper part and the lower part and connect the two parts
together. In addition, the device has at least one control unit for
exciting the piezoelectric vibratory elements and thus the elastic
elements and a sorting device installed in the area of the guide
channel to separate the good tablets from the bad.
Inventors: |
Heim; Ralf; (Laupheim,
DE) ; Krahl; Wolfgang; (Laupheim, DE) ;
Kronawitter; Michael; (Biemerstetten, DE) ;
Armbruster; Rolf; (Neu-Ulm, DE) ; Geiselhardt;
Bernd; (Schemmerberg, DE) ; Noe; Joachim;
(Ehingen, DE) |
Correspondence
Address: |
JANSSON SHUPE & MUNGER LTD.
245 MAIN STREET
RACINE
WI
53403
US
|
Assignee: |
UHLMANN PAC-SYSTEME
Laupheim
DE
|
Family ID: |
38617927 |
Appl. No.: |
12/134599 |
Filed: |
June 6, 2008 |
Current U.S.
Class: |
53/500 ; 198/437;
198/457.05 |
Current CPC
Class: |
B65G 2201/027 20130101;
B65G 27/16 20130101; B65G 27/34 20130101; B65G 27/04 20130101 |
Class at
Publication: |
53/500 ; 198/437;
198/457.05 |
International
Class: |
B65B 1/08 20060101
B65B001/08; B65B 1/30 20060101 B65B001/30 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 15, 2007 |
EP |
07 011 833.6 |
Claims
1. A conveying system for tablets comprising: two devices for
conveying tablets, each having a lower part, an upper part with at
least one guide channel for holding and conveying the tablets, and
several elastic elements, arranged a certain distance apart from
each other, to each of which at least one piezoelectric vibratory
element is attached, wherein the elastic elements are arranged
between the upper part and the lower part and connect them
together, wherein the two devices are arranged in a cascade, so
that the guide channel of the device coming first in the direction
in which the tablets are conveyed is higher than the guide channel
of the second device; at least one control unit for exciting the
piezoelectric vibratory elements and thus the elastic elements; an
inspection device located above each guide channel of the second
device to check the quality of the tablets being conveyed in the
guide channel; and a sorting device, located in the area of each
guide channel, to separate the good tablets from the bad, wherein
the second device conveys the tablets at a higher speed than the
first device, and the speed at which the tablets are conveyed can
be controlled to single out the tablets from each other for the
quality control operation performed by the inspection device.
2. The conveying system for tablets according to claim 1 wherein
the second device has a greater angle to the horizontal than the
first device.
3. The conveying system for tablets according to claim 1 wherein
the elastic elements of the second device are excited at a higher
frequency than the elastic elements of the first device.
4. The conveying system for tablets according to claim 1 wherein
each upper part comprises a plurality of guide channels arranged
parallel to each other.
5. The conveying system for tablets according to claim 1 wherein
each guide channel of the second device has a pass-through opening
for tablets, which is arranged near one of the longitudinal walls
of the guide channel.
6. The conveying system for tablets according to claim 1 wherein
each guide channel of the second device has an angled section or
recess extending in the longitudinal direction leading to the
pass-through opening.
7. The conveying system for tablets according to claim 1 wherein
the inspection device for checking the quality of the tablets being
conveyed in the guide channel is designed as a NIR measuring
device, as a capacitive probe, as a laser, or as a camera.
8. The conveying system for tablets according to claim 1 wherein
the elastic elements are held in place by clamping blocks, each of
which is attached to the upper part or to the lower part.
9. The conveying system for tablets according to claim 1 wherein
each elastic element is designed as a support plate, which is
mounted transversely to the direction in which the tablets are
conveyed and is connected by screws to the clamping blocks, wherein
two piezoceramic plates serving as piezoelectric vibratory elements
are mounted on each support plate a certain distance apart.
10. The conveying system for tablets according to claim 1 wherein
each guide channel has sections arranged in the form of a cascade
extending in the direction in which the tablets are conveyed.
11. The conveying system for tablets according to claim 1 wherein
the angle of each guide channel to the horizontal is in the range
of 0-10.degree. , and preferably in the range of 5-7.degree., and
the angle of the elastic elements to the bottom part is in the
range of 83-89.degree., and preferably in the range of
86-87.degree..
12. The conveying system for tablets according to claim 1 wherein
the sorting device comprises an electromagnetically actuated
finger, which can be moved transversely to the direction in which
the tablets are conveyed.
13. The conveying system for tablets according to claim 1 wherein
the sorting device comprises a device for delivering a blast of
air.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority based on European patent
application EP 07 011 833.6, filed Jun. 15, 2007.
FIELD OF THE INVENTION
[0002] The invention pertains to systems for conveying tablets.
DESCRIPTION OF THE PRIOR ART
[0003] Devices for conveying tablets are used in the drug packaging
industry as part of a filling device, for example, by means of
which bottle-like containers can be filled with a large number of
tablets, so that a patient will have a sufficient quantity of
tablets available for several weeks of daily administration, for
example. So that the containers can be filled with the correct
number of tablets, it is necessary to single out the tablets before
the bottles are filled so that a product inspection and a counting
operation can be performed.
[0004] There are several different possibilities for doing this.
The tablets are usually brought up by a conventional vibratory
conveyor, introduced into a filling tube, and detected and counted
as they drop into the container. Conveying tablets by means of a
conventional vibratory conveyor sometimes damages the tablets. In
addition, product control is more or less impossible in this way,
and the reaction of the system upon reaching the desired number of
tablets is slightly delayed, so that sometimes a wrong number of
tablets arrives in a container.
[0005] In other types of filling devices as well, the tablets are
usually brought up by a conventional vibratory conveyor, singled
out by means of a complicated mechanism, and detected individually
before they are deposited in the containers; see, for example, EP 1
389 583 A1 or U.S. Pat. No. 6,505,460 B2. These types of filling
devices are complicated to manufacture, but in addition they have
not yet been developed to the point where they are ready for the
market. Product inspection or counting is known from DE 102 42 243
A1. The tablets are sent along guide channels of a vibratory
conveyor, which comprises an opening in the bottom of the guide
channel for the automatic discharge of mechanically damaged
tablets.
[0006] Piezoelectric vibratory conveyors are also known, which are
used in various areas outside the pharmaceutical industry; see, for
example, DE 100 05 933 B4, DE 203 20 326 U1, and DE 103 40 455 B4.
Using these types of conveyors for tablets has been considered too
expensive so far, because electromagnetic vibratory conveyors can
be manufactured much more cheaply, and also because piezoelectric
vibratory conveyors were not originally designed to single out
tablets.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a
conveying system for tablets in which the tablets can be conveyed,
counted, and inspected easily and reliably.
[0008] According to an aspect of the invention, the conveying
system for tablets includes two devices for conveying the tablets,
each having a lower part, an upper part with at least one guide
channel for holding and conveying the tablets, and several elastic
elements, arranged a certain distance apart from each other, to
each of which at least one piezoelectric vibratory element is
attached, wherein the elastic elements are arranged between the
upper part and the lower part and connect them together. The
conveying system also includes at least one control unit for
exciting the piezoelectric vibratory elements and thus the elastic
elements, and a sorting device, located in the area of the guide
channels, for separating the good tablets from the bad tablets.
[0009] The two devices are arranged in a cascade, so that the guide
channel of the device coming first in the direction in which the
tablets are conveyed is higher than the guide channel of the second
device. In addition, the conveying system has an inspection device
above each of the guide channels of the second device to check the
quality of the tablets being conveyed down the guide channel. The
second device conveys the tablets at a higher speed than the first
device, and the speed at which the tablets are conveyed can be
controlled to single them out from each other so that they can be
subjected to the quality control operation performed by the
inspection device.
[0010] As a result of this arrangement, it is ensured that the
tablets are singled out in the guide channel. This is necessary so
that the tablets can be counted easily and so that the quality
inspection of the individual tablets can be carried out while they
are still in the guide channel. In addition, because both the
inspection device and the sorting device are located in the area of
the guide channel, it is easy to separate the good tablets from the
bad.
[0011] Each upper part preferably comprises a plurality of guide
channels, arranged parallel to each other, as a result of which
manufacturing costs can be decreased and the overall throughput of
the device increased.
[0012] So that the good tablets can be separated easily from the
bad, it is advantageous for each guide channel to comprise a tablet
pass-through opening, which is located close to one of the
longitudinal walls of the guide channel.
[0013] So that the good tablets can be separated even more
efficiently from the bad, each guide channel comprises an angled
section or depression extending longitudinally toward the
pass-through opening, the width of this angled section or
depression being smaller than the width of the guide channel. Thus
it is possible for certain tablets to be moved down the angled
section or depression toward the pass-through opening at the same
time that the other tablets are being conveyed along the web, which
occupies the rest of the width of the guide channel.
[0014] The inspection device for checking the quality of the
tablets being conveyed down the guide channel is designed as an NIR
measuring device, as a capacitive probe, as a laser, or as a
camera.
[0015] A simple mechanical arrangement of the device consists in
mounting the elastic elements by means of clamping blocks, each of
which is attached to the upper part or to the lower part.
[0016] An especially effective vibratory conveying device is
obtained by designing each of the elastic elements as a support
plate, which is arranged transversely to the conveying direction of
the tablets and which is connected to the clamping blocks by
screws, wherein two piezoceramic plates, serving as piezoelectric
vibratory elements, are mounted on each support plate a certain
distance apart.
[0017] So that the tablets can be singled out even more
effectively, each guide channel can comprise sections arranged in
the form of a cascade proceeding in the direction of tablet
conveyance.
[0018] The tablets can be conveyed at an especially high speed
while simultaneously avoiding the accumulation of several tablets
in one guide channel by setting each guide channel at an angle of
0-10.degree., and preferably of 5-7.degree., to the horizontal and
by setting the elastic elements at an angle of 83-89.degree.,
preferably of 86-87.degree., to the lower part.
[0019] The sorting device can be advantageously designed as an
electromagnetically actuatable finger, which can be moved
transversely to the transport direction of the tablets, or as a
device for delivering a blast of air. Both mechanisms can be
activated and deactivated as a function of the result of the
quality control operation.
[0020] As previously mentioned, the two devices are arranged to
form a cascade, so that the guide channel of the device coming
first in the direction of tablet conveyance is higher than the
guide channel of the second device, wherein the second device
conveys the tablets at a higher speed than the first device. This
is accomplished, for example, by setting the second device at a
greater angle to the horizontal than the first device.
Alternatively or in addition, the elastic elements of the second
device can be excited at a higher frequency than the elastic
elements of the first device. Thus the tablet streams at the
transition between the guide channels are pulled apart very
effectively, and the tablets are singled out.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Additional details, features, and advantages of the present
invention can be derived from the following description, which is
based on the drawings.
[0022] FIG. 1 is a perspective view of a device for conveying
tablets, which forms a part of the inventive conveying system;
[0023] FIG. 2 is a perspective view of the supporting parts of the
device for conveying tablets, wherein the upper part with the guide
channels is not shown;
[0024] FIG. 3 is a schematic diagram of a special embodiment of the
elastic element with two piezoceramic plates mounted on it;
[0025] FIG. 4 is a perspective view of a variant of the device for
conveying tablets;
[0026] FIG. 5 is a side view of the device for conveying tablets;
and
[0027] FIG. 6 is a perspective view of an inventive conveying
system for tablets.
DETAILED DESCRIPTION OF THE INVENTION
[0028] FIG. 1 shows an exemplary embodiment of a device for
conveying tablets, which forms a part of the inventive conveying
system. In the example shown here, the device for conveying tablets
comprises an upper part 2 with three parallel guide channels 4 to
hold and convey the tablets 6. In addition, the device has a lower
part 8, which stands on rubber feet 10. As shown in FIG. 2, upper
part 2 and lower part 8 are connected by several elastic elements
12, arranged a certain distance apart from each other.
[0029] By means of the vibratory conveying system described further
below, it is possible to single out tablets 6 being supplied to a
guide channel 4 by using control devices (not shown) to actuate
suitably the individual components of the vibratory conveying
system, in such a way that each tablet 6 can be counted exactly and
subjected individually to quality control.
[0030] It is possible to arrange nearly any desired number of guide
channels 4 next to each other, wherein a number of two to four
guide channels 4 is currently preferred.
[0031] Each guide channel 4 has two longitudinal boundary walls 14,
which determine the U-shaped design of the guide channels 4 and
define the direction in which tablets 6 are conveyed. In a terminal
section of guide channels 4, near one of the longitudinal walls 14,
an angled section or recess 16, extending in the longitudinal
direction, is provided, the width of which is smaller than the
width of guide channel 4. In the example shown here, the width of
the recess 16 is approximately half the width of guide channel 4.
The section 20, which remains on the other side of guide channel 4,
can also, like recess 16, slant down toward its associated
longitudinal wall 14; that is, a profile is formed with a crest 18
in the middle of guide channel 4. It is also possible that recess
16 could have a different shape, and that section 20 could be
designed as a web. There are many possible mechanical designs which
could be used here to ensure the effective division of guide
channel 4 into two areas. In some cases it would even be possible
to leave out recess 16.
[0032] In the preferred embodiment shown here, each guide channel 4
also has a pass-through opening 22, located near one of the
longitudinal walls 14 of guide channel 4, for tablets 6. The
pass-through opening 22 serves here to accept tablets 6 which have
been identified as "good" and leads to a filling tube (not shown),
which, during operation, remains closed at its bottom end by a cap
until the desired number of tablets 6 has been verified by a
counting device (also not shown), which counts the tablets
remaining on guide channel 4. Then the cap is opened, and the
predetermined number of tablets 6 is discharged into the
appropriate bottle-like or can-like container. For this purpose,
several devices, parallel to each other, are preferably used, so
that a larger number of containers can be filled simultaneously. It
is also conceivable that the device for conveying tablets could be
used in other applications in which tablets are to be fed forward
without damaging them.
[0033] In addition to the previously mentioned counting device, an
inspection device (not shown) is installed above each guide channel
4 to check the quality of tablets 6 being conveyed down guide
channel 4. The inspection device can be, for example, a
conventional camera, which merely examines the tablets for
lamination, capping, picking, etc., but it could also be designed
as a NIR measuring device, which can check the consistency of
tablets 6. A capacitive probe, a laser, or any other desired type
of inspection device could also be used. Downstream of the
inspection device, a sorting device 24 is provided, which serves to
separate tablets 6 found to be "good" from those found to be "bad".
In the example shown in FIG. 1, the sorting device 24 is designed
as an electromagnetically actuated finger, which can move
transversely to the direction in which tablets 6 are being conveyed
and which, when actuated, pushes a tablet 6 from section 20 of
guide channel 4 into recess 16. It is also conceivable that a
device for delivering a blast of air transversely to the direction
in which tablets 6 are being conveyed could be provided as a
sorting device 24. In the example shown, tablets 6 found to be good
are moved by sorting device 24 into recess 16, where they continue
to travel until they reach the pass-through opening 22. It is
equally possible to actuate sorting device 24 only when a tablet 6
found to be bad is to be separated out. Because most of tablets 6
will be classified as good, this reduces the actuating rate of
sorting device 24. Tablets 6 classified as bad can then be sent
through pass-through opening 22, or no pass-through opening 22 at
all can be provided, and instead the good and bad tablets 6, which
have been separated from each other, can continue to travel until
they reach end of guide channel 4, at which point they are then
processed separately.
[0034] FIG. 2 shows the vibratory conveyor system of the device in
detail. The lower part 8 comprises a base plate 26, from which
longitudinally oriented side plates 28 project upward. The side
plates 28 extend along each of the longitudinal sides of the base
plate 26 and are arranged in a row, a certain distance apart.
Clamping blocks 30 are attached to the end surfaces of side plates
28 by screws 32. A support plate is clamped between the clamping
block 30 and side plate 28; in the present example, this support
plate forms elastic element 12. Two piezoelectric vibratory
elements 34 are mounted on support plate 12, which forms a
connection between two side plates 28 and is arranged transversely
to the conveying direction of tablets 6. It has been found to be
especially advantageous to use piezoceramic plates as piezoelectric
elements 34, as a result of which a double spring is formed, which
ensures the production of up to 30,000 longitudinal linear
vibrations per minute.
[0035] A piezoelectric vibratory element 34 of this type is shown
in detail in FIG. 3. Piezoceramic plates 34 are set into vibration
by a suitable alternating voltage applied by a control unit (not
shown) by way of a cable 36. These vibrations are transmitted to
the support plate, acting as elastic element 12, and excite it. In
principle, it can also be sufficient to provide merely one
piezoelectric vibratory element 34 on elastic element 12. The
connection between elastic element 12 and piezoelectric vibratory
element 34 is preferably accomplished by means of an adhesive, but
other types of attachment are also conceivable.
[0036] By using several coordinated control units, each of which
applies an alternating voltage to piezoelectric vibratory elements
34, to actuate the various piezoelectric vibratory elements 34,
which are arranged a certain distance apart, in a coordinated
manner, it is possible to move the tablets along the downward
slanting guide channel 4 in almost any way desired. Thus, in the
inventive conveying system, it is also possible to single out
tablets 6 from each other in each guide channel 4.
[0037] The middle area of support plate 12 is also attached by a
clamping block 38 to an angle profile 40, which is connected to
upper part 2 of the device. In this way, the vibrations generated
by the vibratory conveyor system are transmitted to upper part 2
and thus also to guide channels 4.
[0038] The design of piezoelectric vibratory elements 34 and of
elastic elements 12 can be modified as desired on the basis of
existing developments in the area of piezoelectric conveyor
technology. Thus, for example, piezoelectric vibratory element 34
can comprise additional layers or be designed in different ways.
The mechanical connection between elastic element 12 and upper part
2 or lower part 8 of the device can also be modified.
[0039] FIG. 4 shows a variant of the device, in which the
singling-out of tablets 6 in guide channels 4 is supported by
dividing guide channel 4 into several successive sections,
following each other in the longitudinal direction in the manner of
a cascade.
[0040] It is has been found by experiment that the angle a to the
horizontal shown in FIG. 5, which is the same as the angle between
slanted lower part 8 and the floor, should be in the range of
0-10.degree., and preferably in the range of 5-7.degree.. At an
angle in this range, a transport rate of up to 20 m/min is possible
in the previously described examples, which corresponds to the
transport of approximately 1,000 tablets/min at a distance between
products of 5-10 mm in guide channel 4. Tablets 6 essentially slide
down guide channels 4. Certain nodal points or dead areas in guide
channel 4 can be avoided by the use of leveling compounds.
[0041] The spring angle .beta. between elastic elements 12 and
lower part 2 should be in the range of 83-89.degree., and
preferably in the range of 86-87.degree.. As a result, a relatively
balanced relationship is obtained between vertical and horizontal
acceleration of tablets 6.
[0042] FIG. 6 shows a conveyor system according to the invention
which is especially advantageous with respect to the singling-out
of tablets 6 from each other. In this system, one of the previously
described devices is combined with a device which is of similar
design but which does not comprise a sorting device 24. The two
devices are arranged in a cascade in such a way that the guide
channel 4' of the device coming first with respect to the direction
in which tablets 6 are conveyed is higher than guide channel 4 of
the second device, wherein the second device conveys tablets 6 at a
greater speed than the first device does. This is accomplished, for
example, in that the second device has a greater angle .alpha. to
the horizontal than the first device. Alternatively or in addition,
elastic elements 12 of the second device can be excited at a higher
frequency than the elastic elements 12' of the first device. Thus
the tablet streams are drawn apart especially effectively at the
transition between the two guide channels 4', 4, and tablets 6 are
singled out from each other. Sorting device 24, normally provided,
is not shown here.
[0043] Within the scope of the present invention, all other types
of solid medications such as capsules, dragees, etc., are also
considered tablets 6. The inspection device checks the tablets for
defects such as breakage, color, or active ingredient, and the bad
tablets are sorted out while they are still in guide channel 4.
Thus a conveying system for tablets is provided, which moves the
tablets along at a controllable transport speed in a gentle manner
not damaging to the tablets and which at the same time ensures that
the tablets are singled out from each other, which makes it
possible for the tablets to be counted and to be subjected to
quality control while they are still in the guide channel 4.
* * * * *