FEEDER FOR A THERMOFORMING MACHINE
The feeder for tablets, capsules or dragées has a stationary base unit and an exchangeable format unit with a sorting plate for evenly distributing the products and with a filling unit including a number of vertically extending filling tubes having a guiding channel for receiving the tablets, capsules or dragées from the sorting plate, and a blocking slide unit for temporarily blocking the guiding channels of the filling tubes. The base unit has a first hanger device for the sorting plate, a second hanger device for the filling unit, and at least one adjusting device for adjusting the first hanger device relative to the second hanger device.
This application claims the benefit of European Patent Application No. EP 08 007 414.9 filed on Apr. 16, 2008, entitled “FEEDER FOR A THERMOFORMING MACHINE” the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention pertains to a feeder for a thermoforming machine.
Thermoforming machines or blister machines, especially in the pharmaceutical area, are used to package products individually, for which purpose, thermoplastic sheet is pulled from a supply roll in the thermoforming machine and sent to a heating station, in which the thermoplastic sheet is heated to the preforming temperature, so that the pockets which are intended to hold the product, which is made available as bulk material, can then be formed in the thermoplastic sheet in a forming station. The pockets in the thermoplastic sheet are usually made in a matrix-like or grid-like pattern and are then filled. Then the thermoplastic sheet with the filled pockets can be covered by a sealing film and hermetically sealed. Merely for the sake of completeness it should be mentioned that, downstream from the sealing station, a thermoforming machine usually comprises a stamping station, in which the blister packages with their filled pockets are stamped out. The capacity of a thermoforming machine also depends largely on how fast the pockets formed in the thermoplastic sheet can be filled, which depends in turn on the capacity of the other stations, for which purpose feeders have been developed to make it possible to fill several pockets simultaneously.
From the prior art, especially from the publicly known prior uses of Aylward Enterprises, Inc., USA, it is known that feeders of this type can be used in the pocket-filling station of a thermoforming machine to fill the pockets in the strip being conveyed through the filling station. The arrangement of filling tubes assigned to the pockets must be adapted precisely to the arrangement of the pockets in the strip, so that the small items can be deposited precisely into the pockets. When a change of format is to be made or when a different type of product is to be packaged, it is therefore necessary to remove and to clean the filling tube carrier and the filling tubes, for which purpose the filling tubes are removed from the filling tube carrier, so that even the smallest amounts of residual material can be cleaned off, as is necessary in particular when the small items are in the form of pharmaceutical products, no residues of which may remain on the filling tubes or on the filling tube carrier.
So that several pockets can be filled simultaneously, several filling tubes are usually assigned to a plurality of channels, which are combined into a filling shoe. Several filling shoes are combined in turn into a filling shoe unit, which forms a part of the dispenser unit. This filling shoe unit can be lowered vertically to dispense the small items and then raised again after the dispensing to allow the sheet which is to be or which has been filled to pass by without interference. So that only one item is ever dispensed at a time from a filling tube into the assigned channel, blocking fingers are used, by means of which the lowermost product in the stack formed in the filling tube can be released. The determining factor for the feed capacity of the feeder is the filling of the filling tubes; that is, it must be guaranteed that all of the filling tubes are always filled. This demands in turn that the feeder can transfer the products to the filling tubes uniformly over the entire surface area of the sorting plate.
In the case of conventional blister machine feeders, a format unit for the filling of the pockets comprises a sorting plate and a filling unit with a blocking slide unit, wherein the sorting plate is suspended elastically by way of resilient pads and is oscillated by vibrators attached to the sorting plate. The conventional arrangement suffers from the disadvantage that, because of the elastic mounting, it is difficult to position the sorting plate precisely with respect to the filling tubes of the filling unit. The requirements with respect to manufacturing tolerances are also high.
In the case of the previously known feeders with sorting plates, the plates comprise openings, into which the upper ends of the filling tubes project. The edges of the sorting plate are designed in such a way that the products to be fed can be loaded onto the plate as if into a flat-bottomed tray, wherein the sorting plate is moved vertically up and down, as a result of which the positions of the upper ends of the filling tubes change relative to the bottom of the sorting plate, which facilitates the sorting of the product items into the filling tubes. This effect is supported by additional drive units assigned to the sorting plate, which cause the product items on the sorting plate to execute “microjumps”, which are intended to promote the homogeneous distribution of the product items on the sorting plate.
With respect to the pattern of these movements of the sorting plates, however, feeders of this type suffer from several disadvantages, because, although the vertical movements of the sorting plate intended to produce the microjumps do loosen the product “carpet” formed by the products on the sorting plate, they cannot distribute the products uniformly over its surface. Product items are frequently missing in particular at the edges and in the corners of the sorting plate, so that the filling tubes present there cannot be filled reliably. This limits the capacity of the system. This can be compensated to only a limited extent by increasing the quantity of product on the sorting plate, because, although it is true that a sufficient quantity will be available in the disadvantaged zones, piles will form at the same time in the center of the sorting plate, which make it more difficult for the products to drop into the filling tubes.
With respect to the movements impressed on the sorting plate to produce the microjumps, it must be kept in mind that this is usually associated with an elastic mounting of the sorting plate on resilient pads, wherein the microjumps are generated by vibrators, which, in conjunction with the mounting of the sorting plate, lead to circular movements of the product carpet, which means that the product items in the center and in the corners hardly move at all. Depending on how the format unit is equipped with filling tubes, individual resonant frequencies develop and thus characteristic configurations are formed on the sorting plates, which means dead zones with little or no vibration, where again the product items hardly move at all, are present. To excite the sorting plates, pneumatic piston vibrators are usually used, which are characterized by their compact design. The disadvantage, however, is that several of these pneumatic piston vibrators are required, and they must be mounted in different positions. As a result of the mounting of the sorting plate on resilient pads and the design of the pneumatic piston vibrators, precise synchronization is not possible, and the reproducibility of the product distribution is not guaranteed.
In the case of feeders with a base unit and a blocking slide unit, which comprises slide guides and blocking slide base plates which move in the slide guides, it is advantageous for the blocking slide unit to be connected detachably to the base unit for maintenance or cleaning. In the case of conventional feeders, this is accomplished by plungers attached to the base unit, wherein spring elements press the blocking slide base plates onto the plungers. The advancing movement is produced by a single-acting pneumatic cylinder, which works against the spring elements and thus puts them under tension. The return stroke takes place exclusively by means of the spring elements. In the case of the conventional feeders, spring elements are attached on both sides of the blocking slide unit to ensure a uniform stroke.
When the conventional feeders are disassembled for cleaning or maintenance, the blocking slide unit with its blocking slide base plates must be removed. To prevent these plates from being pushed unintentionally out of the lateral guides by the force of the springs, a locking device is required. When this locking device is released, the blocking slide base plates can be removed, wherein care must be taken to ensure that, during this removal process, the spring elements, which are now loose, do not become lost.
The conventional feeders also suffer from the disadvantage that, because of the many small mechanical parts required for the detachable connection of the blocking slide unit to the base unit and for the transmission of movement from the base unit to the blocking slide unit, these conventional feeders are expensive to manufacture.
A format unit comprises the sorting plate, the filling unit with the blocking slide unit and the filling tubes, and the filling shoes, which can be selected to suit the products to be supplied and sorted. In the case of a conventional feeder, the format unit is attached to the base unit by a hanger device to secure it against shifting, wherein the attachment process is usually done by hand with the use of star handles and a clamping strip. This method of attachment suffers from the disadvantages that the star handles are not readily accessible, and that it is necessary to deal during the attachment process with many individual parts, which can become lost when the format unit is changed. In addition, the additional edges make it even more difficult to the clean the base unit and the format unit.
Conventional blocking slide units comprise a number of blocking fingers corresponding to the number of filling tubes, each of these fingers being assigned to one of the filling tubes, and a base plate with a number of through-openings, wherein the base plate comprises sockets for the blocking fingers. In the case of the conventional blocking slide units, the sockets for the blocking fingers are milled into the surface of the base plate.
During the production of the conventional blocking slide units, this leads to a first disadvantage that, because of the very small geometric forms and the large number of sockets, a long machine operating time is required to produce them. During the handling of the conventional blocking slide units, this leads to the second disadvantage that, because the sockets are introduced only into the top surface of the base plate, they make these units very difficult to clean. Because of their geometry, the corners of these sockets cannot be adequately cleaned, as a result of which residues can remain behind on the base plate.
Because of the danger of contamination with dust and the corresponding requirements, it is conventional for the feeder to have an external control panel. The feeder is arranged on a machine table of the blister machine, wherein the control panel is set up next to the blister machine.
This arrangement suffers from the disadvantage that the electrical lines must be laid individually into the control panel, because only there can the motors and sensors be connected to the control mechanism. The electrical lines extend along the filling section, where they can become contaminated with tablet dust. This increases the amount of cleaning work required. The external control panel, furthermore, requires additional space next to the blister machine and can under certain conditions interfere with access to the blister machine and make it more difficult to operate the machine.
SUMMARY OF THE INVENTIONIt is an object of the invention to provide a feeder, where the desired arrangement of the sorting plate with respect to the filling tubes of the filling unit is to be accomplished more easily, and in addition the requirements on manufacturing tolerances are to be lowered.
According to an aspect of the invention, the feeder for tablets, capsules or dragées comprises a stationary base unit and an exchangeable format unit comprising a sorting plate for evenly distributing the products and a filling unit including a number of vertically extending filling tubes having a guiding channel for receiving the tablets, capsules or dragées from the sorting plate, and a blocking slide unit for temporarily blocking the guiding channels of the filling tubes. The base unit comprises a first hanger device for the sorting plate, a second hanger device for the filling unit, and at least one adjusting device for adjusting the first hanger device relative to the second hanger device.
As a result, manufacturing tolerances can be compensated by way of a simple relative mechanical adjustment of the hanger devices, and the sorting plate and the filling tubes can be positioned very accurately with respect to each other. It can thus be guaranteed that the filling unit with the filling tubes is centered precisely with respect to the openings provided for them in the sorting plate, as a result of which the process of sorting the tablets into the filling tubes is realized in optimal fashion. Another advantage is that the different format units can be designed to be hung onto different feeders in the same way, so that maintenance work is simplified, and it becomes easier to refit a feeder with a new format unit.
According to one exemplary embodiment, the adjusting device is assigned to the first hanger device. Alternatively or in addition, the adjusting device can be assigned to the second hanger device. The assignment of an adjusting device to a hanger device makes it very easy to make the necessary adjustments, and the additional assignment of a second adjusting device to the second hanger device brings about even more improved adjustment possibilities for positioning the filling tubes with respect to the sorting plate.
The adjusting device preferably comprises an adjusting cam. This makes it possible to make the desired adjustments very easily during the assembly of the feeder, because the hanger devices can be positioned on the base unit once and for all by adjustment of the cam when they are attached.
It has been found to be advantageous for the first hanger device to be mounted on a first pin, which rests in a first guide groove in the adjusting device assigned to the first hanger device and/or for the second hanger device to be mounted on a second pin, which rests in a second guide groove in the adjusting device assigned to the second hanger device. In particular, both the first and the second hanger devices can each be mounted on two pins. This gives the hanger devices secure support and thus ensures that the sorting plate and the filling unit are securely supported.
The invention is explained in greater detail in the following on the basis of the exemplary embodiments illustrated in the drawings.
The feeder 1 shown in
According to an exemplary embodiment not shown in the drawings, it is also possible to provide a second guide, which is designed to form a compound table together with the first guide in order to make possible a second movement in a horizontal direction which is not parallel to the first horizontal direction.
With a feeder 1 designed in this way, it is possible to transfer product items from the bulk material in the supply container 18 via the product conveyor 22 (
As shown in
There is also the possibility of varying the amplitude and/or the frequency and/or the symmetry of the oscillations, which means that a high degree of flexibility is obtained in terms of controlling the sorting behavior, which is influenced by the size of the product items, their contact surface areas, and their weights, all of which can be taken into consideration as appropriate.
So that the tablets can be individuated, the blocking slide base plates 19 and 20 in an advantageous embodiment are moved back and forth in opposite directions, wherein these movements are transmitted directly from the base unit 2 to the blocking slide base plates 19, 20. The blocking slide base plates 19, 20 are guided in the slide guides 33 and thus execute linear movement.
When the feeder is to be changed over to a new tablet format, the old blocking slide unit 4 must be removed from the base unit 2 and the new one attached to it. As can be seen in
The receiving portions 43 for the blocking fingers 41 can be cut out of the base plate 42 by means of a laser cutting system, for example, together with the first through-openings 49. It is advantageous for the receiving portions 43 for the blocking fingers 41 to have a narrowed section at the point where they connect to the first through-openings 49. As shown in
In the locked state, the upper retaining plate 45 with the corresponding through-openings is preferably attached to the base plate 42 in such a way that these through-openings essentially coincide with the through-openings 49 in the base plate 42.
The end position of the upper base plate 42b is adjustable, so that the tablets in the filling tubes 10 can be blocked off in optimal fashion. The adjusting distance is preferably continuously variable. This can be accomplished by the use of a motor. The upper base plate 42b is moved by a pneumatic cylinder 59, which comprises a continuous piston rod. A stop 60 can be used to set the desired position, wherein the stop can be adjusted by the motor, so that no manual interventions are required.
The technical features of these exemplary embodiments of the present invention can be combined with each other. It is also possible to replace the base plate 42 by a number of partial base plates or to replace the upper base plate 42b by a number of upper partial base plates and the lower base plate 42a by a number of lower partial base plates.
Claims
1. A feeder for tablets, capsules or dragées, comprising:
- a stationary base unit; and
- an exchangeable format unit comprising: a sorting plate for evenly distributing the products; and a filling unit including a number of vertically extending filling tubes having a guiding channel for receiving the tablets, capsules or dragées from the sorting plate, and a blocking slide unit for temporarily blocking the guiding channels of the filling tubes;
- wherein the base unit comprises a first hanger device for the sorting plate, a second hanger device for the filling unit, and at least one adjusting device for adjusting the first hanger device relative to the second hanger device.
2. The feeder according to claim 1, wherein the adjusting device is assigned to the first hanger device.
3. The feeder according to claim 1, wherein the adjusting device is assigned to the second hanger device.
4. A feeder according to claim 1, wherein the adjusting device comprises an adjusting cam.
5. The feeder according to claim 1, wherein the first hanger device is supported by at least one first pin, which rests in a first guide groove in the adjusting device assigned to the first hanger device.
6. The feeder according to claim 5, wherein the first hanger device is supported by two first pins.
7. The feeder according to claim 1, wherein the second hanger device is supported by at least one second pin, which rests in a second guide groove in the adjusting device assigned to the second hanger device.
8. The feeder according to claim 7, wherein the second hanger device is supported by two second pins.
Type: Application
Filed: Apr 15, 2009
Publication Date: Oct 22, 2009
Inventors: Erich JANS (Orsenhausen), Kurt GNANN (Biberach), Martin ZULEGER (Achstetten), Markus REGNER (Muttensweiler), Wolfgang RODI (Laupheim-Baustetten), Juergen LIEBHARDT (Laupheim), Christian HESS (Mietingen)
Application Number: 12/424,276
International Classification: B65B 5/06 (20060101);