EP0803302A1 - Method and apparatus for working a product in several stages - Google Patents

Abstract

Multi-stage press-forming method with at least two stations with top and bottom tools and transfer of the product between stations, in which the products are processed simultaneously in all stations, are held for a given time after processing and are released for transfer at timed intervals. Appropriate tooling is also claimed.

Description

The invention relates to a method according to the preamble of claim 1 and a device according to the preamble of claim 8.

Such a method and such a device are known from CH-A-613 135. For the production of hollow bodies from thin strip or sheet metal, such as cans or similar containers, a flat starting material is gradually transformed into the desired final shape in several deformation stages. This is done in multi-stage deep-drawing tools. In these, the end product is shaped by gradually drawing the hollow body to an ever greater depth while simultaneously reducing the outside diameter, it being possible in principle to provide any number of deformation stages. The number of deformation stages required in an individual case depends on the desired final shape of the hollow body and the deformation properties of the material used. In any case, it is necessary to transport the product between the individual deep-drawing stations.

In the above-mentioned CH-A-613 135 it has already been stated that previous solutions with mechanical conveying devices can no longer be satisfied due to the masses to be moved of such devices at the working speeds required today. For this reason, compressed air is provided as the drive in this prior art. The thermoformed products are countered in every station Moving positioning devices in the form of stops, which prevent further transport of the transported product, but enable the product processed (reduced diameter) to be carried out in the respective station. With this known solution, however, it is disadvantageous that the ejection of the products from the tool and the further transport by means of compressed air must be coordinated via an exact time sequence control in order to ensure that the next product is not delivered to any station before the previously processed one Has left the station. Each time the thermoforming system is reset to a product, this requires complex test runs and adjustments that can only be carried out by specialist personnel. The same applies to any readjustments that may be necessary during production, which are necessary even if you want to work at a different speed.

The devices described in DE 26 35 583 C2, EP 0 231 947, EP 0 356 975 and EP 0 149 184 do not solve this problem either.

It is therefore the object of the invention to further develop a method and a device of the type described in the introduction in such a way that a further transport of the products is guaranteed in a self-controlling manner at any working speed, without adjustment or adaptation work being necessary.

This object is achieved by a method having the features of claim 1, and in particular in that the products are processed simultaneously in all processing stages, are temporarily held after processing to prevent further transport and are released for further transport at different times. Because the processed products at the opening stroke to different, coordinated When the time is released for further transport, it is ensured that a subsequent product is only then transported on when the preceding product has left the target position.

Advantageous embodiments of the method according to the invention are specified in subclaims 2 to 7.

The product can be removed from the tool by an ejector in the station. Such an ejector is known from the above-mentioned CH-A-613 135, by means of which the product is removed from the lower tool there and at the same time released for further transport. In order to achieve a coordinated sequence of the transport of the products from the various stations, a time control for actuating the ejectors must be provided in the prior art.

According to the invention, the products are removed from the tools in all stations at the same time during the simultaneous opening stroke of all stations, but are not immediately released for further transport, but are first held on the top of the lower tools by hold-down devices, preferably the ejectors, until an opening stroke of the ejectors is the final one Release of the respective product for further transport.

It is particularly advantageous if the opening strokes of the ejectors begin at different, coordinated times. This ensures in a particularly simple manner that the products processed in the stations are released for further transport at different times, since the ejectors at the opening stroke separate from the products which are arranged in the different processing stations at different times.

Since the upper tools and the ejectors are moved by the same machine component, complex adjustment and control devices can be dispensed with.

According to a further advantageous embodiment of the invention, the products are driven by an air flow, which is preferably interrupted during the working stroke of the device. According to the invention, the air flow would basically not have to be interrupted at all in order to ensure a proper production process. However, the air flow can be switched off for cost reasons, while the products are fixed in the tools during the working stroke. However, the solution according to the invention makes it possible for the air flow to be controlled jointly for all stations for the further transport of the products. A single control can therefore be omitted.

In an advantageous embodiment of the invention, positioning devices are arranged in each station which are designed in such a way that they stop the products transported by the air flow in an oriented manner towards the tool, but allow the product to be transported further after the product has been processed. For this purpose, appropriately dimensioned passage openings are preferably provided in the positioning devices.

According to a further advantageous embodiment of the method according to the invention, the positioning device in question is forcibly moved into the transport path when the upper tool is opened. This also ensures that no adjustment work is required when changing the working speed or the products.

The above-mentioned object is also achieved by a multi-stage machining tool with the features of claim 8.

According to the invention, the upper tools are fastened to a common crosshead and are actuated by this in their movements. On the one hand, this creates a structurally simple solution, since no separate devices and controls are required for the lifting movements of the individual tools. Furthermore, the ejectors are slidably attached to the upper tools in the direction of movement of the crosshead, so that the ejectors are also actuated by the movements of the common crosshead, and separate actuating and / or control devices can also be omitted here. Furthermore, hold-down devices are provided, which are preferably formed by the ejectors, and whose movements with respect to the upper tools are limited in such a way that the hold-down devices, preferably the ejectors, when the tool is opened at different times, inevitably depending on the movement sequence of the upper tool, on its opening stroke take part. Finally, the hold-down devices, preferably the ejectors, are arranged with respect to a product to be processed in such a way that they hold the product up to their respective opening stroke. In this way, a particularly simple and expedient control of the further transport of the products is achieved.

Advantageous embodiments of the device according to the invention are characterized by subclaims 9 to 17.

The ejectors of the various processing stations can be designed so that when the upper tool is opened they initially remain in the position assumed when the tools are closed under the action of a hold-down force, thereby holding the respective product on the upper side of the associated lower tool in the transport plane until them in time successively coupled by stops with the upper tools in motion and taken away by them against the action of the hold-down force during the further opening stroke. The products are only released for further transport in the individual stations when the ejector opening stroke begins. This represents a structurally very simple solution, which enables the successive release of the products. Also, no changes need to be made when the working speed changes.

Each ejector is biased in the ejection direction by a constant hold-down force. Such a hold-down force can be brought about, for example, by a metal spring or a compressed air cushion. This ensures that each ejector ejects the processed product from the die when the upper tool is opened and holds it on the transport level until the ejector's opening stroke begins, i.e. the ejector is removed from the product.

According to a further embodiment of the invention, the stops of the ejectors can be adjustable. Basically, readjustment or readjustment of the stops is not necessary according to the invention. However, the ejectors could have a rod that slidably passed through the crosshead and were provided with adjustable stops above the crosshead.

According to a further embodiment of the invention, compressed air nozzles can be provided as a drive for the transport of the products, which are actuated together. Since, according to the invention, no individual control of the respective compressed air flow is required, the control effort can be significantly reduced.

The positioning device for the product can, according to a further embodiment, advantageously on the upper tool be attached so that it moves when opening the upper tool with this. If the positioning device for the product consists of a collecting basket which has a passage opening for the product, the passage opening is moved into the transport plane when the upper tool is opened, so that the product can be conveyed through the passage opening. It is advantageous here if the passage opening is arranged above the transport plane when the upper tool is fully open, since the subsequent product is then prevented from moving further.

According to a further embodiment of the invention, the collecting basket can have further openings in addition to the passage opening in order to prevent turbulence in the air flow.

Fig. 1

eine Querschnittsansicht eines erfindungsgemäßen Mehrstufen-Tiefziehwerkzeuges mit drei Stationen in geschlossenem Zustand;

Fig. 2

das Tiefziehwerkzeug von Fig. 1, wobei die Oberwerkzeuge teilweise geöffnet sind; und

Fig. 3

das Tiefziehwerkzeug von Fig. 1 in vollständig geöffnetem Zustand.

The invention is described below by way of example using an advantageous embodiment with reference to the accompanying drawings. Show it:

Fig. 1

a cross-sectional view of a multi-stage deep-drawing tool according to the invention with three stations in the closed state;

Fig. 2

the deep-drawing tool of Figure 1, the upper tools are partially open. and

Fig. 3

1 in the fully open state.

The multi-stage deep-drawing tool shown in FIGS. 1 to 3 has (by way of example) three stations I, II and III. In station I, a blank is punched out of thin strip and drawn in a first drawing stage. The second drawing stage is carried out in station II, while the edge of the finished drawn product is trimmed in station III.

Each station has an upper tool 10, 10 ′, 10 ″ and a lower tool 12, 12 ′ and 12 ″, all upper tools being fastened to a common crosshead 14 and all lower tools to a common base plate 16. To eject the product from the respective die of the upper tool 10, 10 ', 10' ', an ejector 18, 18', 18 '' is provided in each upper tool, which is attached to a cylindrical guide shaft 20, 20 ', 20' 'with a widened end part 22, 22 ', 22' 'is attached. Here, the vertical sliding movement of the ejector ends relative to the upper tool in each case at a stop edge 24, 24 ', 24' 'of the respective upper tool.

Compressed air nozzles (not shown) are used to transport the products between the individual stations I, II and III along a transport plane 26, which preferably produce a laminar transport air flow, which is indicated in the figures by an arrow pointing to the left. The respective compressed air nozzles are not controlled individually, but are connected to a compressed air source. With suitable guidance devices, however, the transport can also be accomplished with a turbulent air flow.

As a positioning device for the products to be transported further, the stations II and III each have a collecting basket 28 ', 28''which is attached to the associated upper tool 10', 10 '' and moves together with it. Each collecting basket 28 ', 28''is essentially U-shaped in cross section parallel to the transport plane 26, the base of the U being provided with a passage opening 30', 30 '' for the product to be transported. Here, the passage opening can be selected so that a product can only pass through it if it has been processed at the associated processing station. Below the passage openings 30 ', 30''are further openings (not shown) provided to avoid the occurrence of turbulence in the transport air flow.

The mode of operation of the device shown in FIGS. 1 to 3 is described below.

In the three-station deep-drawing tool shown in FIGS. 1 to 3, a round blank is punched out of thin strip material in station I and the first deep-drawing stage is carried out. After the product processed in station I has been transported to station II, it is subjected to a further deep-drawing process and then transferred to station III for trimming the edge.

Fig. 1 shows the deep-drawing tool in the closed state, i.e. the working stroke is completed and the upper tools 10, 10 'and 10' 'of all stations I, II and III are closed against the lower tools 12, 12', 12 ''. Since all the upper tools 10, 10 ′, 10 ″ are fastened to the common crosshead 14, the working stroke and the opening stroke are carried out simultaneously for all stations.

FIG. 2 shows the deep-drawing tool from FIG. 1, but the crosshead 14 has already partially carried out the opening stroke. As a result, the deep-drawn products A, B and C in stations I, II and III have already been ejected from the upper tool by the ejectors 18, 18 ', 18''. In stations I and II, they are still held by the ejector on the upper side of the lower tool, since the ejectors are pressed vertically downwards by a compressed air cushion acting constantly on the upper side of the ejector stamp 20, 20 '. Although the associated compressed air nozzles are already activated here, the products A and B are still held in their station in this way. In station III, however, the ejector 18 ″ has already released the finished deep-drawn product C, since the upper widening 22 ″ of the ejector 18 ″ on the stop edge 24 '' of the upper tool 10 '' struck and thus the opening stroke of the ejector has been initiated. At the same time, the associated collecting basket 28 ″ has been raised so far in station III that its passage opening 30 ″ is located in the transport plane 26, so that the compressed air flow indicated by an arrow can convey the product C from station III.

3 finally shows the deep-drawing tool in the fully open state. As can be clearly seen, the finished product C has already been expelled from the station III by the air stream and the product B has moved in its place. Since the passage opening 30 ″ of the collecting basket 28 ″ of station III is now above the transport plane 26, the product B strikes the collecting basket 28 ″ and is not conveyed further by the associated transport air flow but is fixed in its position.

In station II it can be seen that the product A is moved into the collecting basket 28 'by the associated compressed air flow and is fixed thereon, since the passage opening 30' is also located above the transport plane 26.

In station I, the thin strip 40 has been advanced as far as is necessary to punch out the next round blank. At the same time, it can be seen in FIG. 3 that when the tool is completely open, all the upper tools and all ejectors 18, 18 'and 18' 'are located clearly above the products, so that they can be transported unhindered.

From the sequence of FIGS. 1 to 3 it can be seen that on the one hand the closing stroke and the opening stroke for all stations I, II and III are carried out simultaneously and that the products A, B and C processed in the stations during the opening stroke are released by the ejectors 18, 18 'and 18''at different times, since they strike their stops 24, 24' and 24 '' at different times when all the tools open simultaneously. Fig. 2 shows that the product C is released first, which has already passed through all processing stations, that is, the opening stroke of the ejector 18 '' begins when the tool is opened, and the opening stroke of the ejector 18 of station I begins when the Tool last.

The transport air flow can be switched off during the working stroke (FIG. 1), but this switching of the air flow is relatively roughly oriented to the tool movement and does not require any fine adjustment during production. The products are guided laterally during transport by guide elements (not shown).

The ejectors 18, 18 'and 18' 'of stations I, II and III described above have a dual function according to the invention, since on the one hand they serve to push the product out of the respective upper tool and on the other hand they are used to hold the product on the top of the associated one To hold the lower tool, which lies in the transport plane. Only from a certain open position of the tool is each ejector 18, 18 ', 18' 'carried along by the associated stop 24, 24', 24 '', whereby the respective products are released one after the other. The laminar air flow emerging from the air nozzles then grasps the workpiece and conveys it to the collecting basket of the subsequent station, which is matched to the external dimensions of the product in the as-yet unprocessed state. Here the product is held in position by the laminar air flow that continues to work until the tool carries out the next working stroke.

Claims (17)

Multi-stage processing method, in which at least two stations in at least two processing stages, a product is first processed by a tool with upper and lower tools and then transported on to a transport level to the next processing stage,
characterized in that - the products are processed simultaneously in all processing stages, - the products are temporarily held after processing to prevent further transport, and - the products are released for further transport at different times. Method according to claim 1,
characterized in that at least in one station the product is released before the product in the station preceding the processing sequence. Method according to at least one of the preceding claims 1 or 2, characterized in that the product is removed from the tool in each station by an ejector and is held on the transport level by a hold-down device, preferably the ejector, with the release being released by an opening stroke of the ejector is effected. Method according to Claim 3, characterized in that an opening stroke of the upper tools takes place after the machining, and that the opening stroke of each ejector in inevitable dependence on the opening stroke of the upper tools begins at a different time. Method according to one of claims 3 or 4, characterized in that the upper tools and the ejectors are moved by the same machine component. Method according to at least one of the preceding claims, characterized in that the products are transported by a preferably laminar air flow which is preferably interrupted during the working stroke of the tools and which is preferably controlled jointly for all stations. Method according to at least one of the preceding claims, characterized in that when the upper tool is opened, a positioning device is first moved into the transport plane in such a way that a passage opening located therein is available for the further transport of the product, while when the opening device is opened further, the positioning device the subsequent product positioned in the station. Machining tool with several stations, with - At least two processing stations (I, II, III) arranged one after the other, each with an upper tool (10, 10 ', 10''), a lower tool (12, 12', 12 '') and an ejector (18, 18 ', 18 ''), and - a drive for product transport,
characterized in that - The upper tools (10, 10 ', 10'') are attached to a common crosshead (14), - The ejectors (18, 18 ', 18'') in the direction of movement of the crosshead (14) are slidably attached to the upper tools (10, 10', 10 ''), and - The movements of hold-down devices, which are preferably formed by the ejectors (18, 18 ', 18''), are limited with respect to the upper tools (10, 10', 10 '') in such a way that the hold-down devices, preferably the ejectors (18 , 18 ', 18''), when opening the tool at different times, inevitably depending on the movement sequence of the upper tool (10, 10', 10 ''), participate in its opening stroke, - The hold-down devices, preferably the ejectors (18, 18 ', 18'') are arranged with respect to a product to be processed such that they hold the product up to their respective opening stroke. Device according to claim 8,
characterized in that, during the opening stroke of the upper tool (10, 10 ', 10''), the ejector (18, 18', 18 '') initially remains in the position assumed when the tool is in the closed position under the action of a hold-down force until it passes through a stop (24, 24 ', 24'') is coupled to the upper tool and is carried by it against the action of the hold-down force during the further opening stroke. Device according to claim 9,
characterized in that the hold-down force is generated by a spring or a constantly acting compressed air cushion. Device according to one of claims 9 or 10, characterized in that the stops (22, 22 ', 22' '; 24, 24', 24 '') of the ejector (18, 18 ', 18' ') or the upper tools (10, 10 ', 10' ') are adjustable. Device according to at least one of the preceding claims 8 to 11, characterized in that jointly controlled air nozzles are provided as the drive for the product transport in order to produce a preferably laminar air flow. Device according to at least one of the preceding claims 8 to 12, characterized in that a positioning device (28 ', 28' ') for the product (A, B, C) is attached to the upper tool (10', 10 ''). Device according to at least one of the preceding claims 8 to 13, characterized in that the positioning device for the product consists of a collecting basket (28 ', 28' ') which has a passage opening (30', 30 '') for the product (A, B, C), which is dimensioned so that the product can only pass through after processing in the associated station. Device according to Claim 14, characterized in that the passage opening (30 ', 30'') of the positioning device (28', 28 '') lies above the transport plane (16) when the upper tool (14) is fully open, so that the next product from the positioning device (28 ', 28'') is stopped and positioned in the station. Device according to claim 14 or 15, characterized in that the collecting basket (28 ', 28' ') has further openings in addition to the passage opening (30', 30 ''). Device according to at least one of the preceding claims 8 to 16, characterized in that the processing station (I, II, III) is a deep-drawing station, a punching station or a cutting station.

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