|Title of Invention||
"A PLANT FOR PROCESSING CONTAINERS AND A CONVEYER FOR CONVEYING CONTAINERS AS WELL AS A PALLET FOR IT"
|Abstract||In order to facilitate production of cans (3,103,103'), in particular of aerosol cans, magnetic conveyors (6,8) and magnetizable pallets (7,107,107') are provided, instead of chain conveyors including mandrels, in plants for producing containers. The cans (3,103,103') are fixed to the magnetizable pallets (7,107,107') and are passed to or through processing stations, for example, by magnetic belt conveyors (6,8). The pallets (7,107,107') are connected to a. connecting portion (132) projecting from the can bottom (130) which may be inserted into a connection opening (117) of the pallet (7,107,107') by a riveting operation. By appropriately arranging the conveying surface (8) of the magnetic conveyor (6,8), the cans (3,103,103') may be oriented at will on the pallets (7,107,107') which are magnetically supported. The can opening is always freely accessible during conveying. In order to compensate for variations of through-put of the plant by simple means, belt conveyors having accumulation zones (46) are provided. (Fig. 5)|
|Full Text||The invention relates to plants according to the introductory clause of claim 1, to conveyors according to the introductory clause of claim 8 and to pallets according to the introductory clause of claim 9.
When processing or treating containers, more particularly when producing them, the same are conveyed to processing stations to perform the respective processing steps, are transferred to them, if necessary, are treated and are subsequently carried away. In order to be able to process the container in a cost saving way, the conveying stations and the processing stations have to be well-suited to each other so that a high through-put of containers can be achieved by simple means without any interference. It has been found that known plants for producing containers have been further developed by some minor improvements of individual processing stations only while the conveying concept remained unchanged over a long period of time.
The fact that those skilled in the art felt bond to a seemingly unimpeachable conveying concept can, in particular, clearly be recognised in the production of cold-pressed containers, such as aerosol cans or tubes. Fig. 1 shows schematically the principal construction of known plants for producing aluminium cans. The procedure of manufacture begins with a pressing step of a press 30. Immediately afterwards, cutting to size and, optionally, brushing of the raw containers or cans is done in a raw processing machinery 31. Subsequently, the cans are put onto mandrels of a chain conveyor 32 and are led through a cleaning station 3 3 including a washing device and a drying device. After cleaning, the interior of the cans is coated with a varnish in an inside varnishing device 34. To this end, each can has to be removed from its mandrel of the chain conveyor, has to be put into a supporting pan, and has then to be
introduced into a sleeve-like rotatable holder. The inside varnish is discharged from a nozzle which is movable into the interior of the can, while the can is rotated. After that, each can has to be removed from the holder, has to be put into a furnace pan and has to be conveyed in it through a first furnace 35 before being put again onto a mandrel of another chain conveyor 32.
For carrying out the movements along the can's longitudinal axis necessary for inside varnishing, energy intensive pulses of pressurised air are used. These pressurised air pulses, the movements of the supporting pans and the motion of the conveying chain have to be synchronised exactly. The supporting pans, die sleeve-like holders and the furnace pans are adapted to meet the respective actual can diameter and have to be exchanged whenever producing cans of another diameter, thus, leading to long periods of disuse.
In order to compensate for short differences in through-put of the inside varnishing processing station 34, 35 and of the cleaning station 33, a first storage chain 36 is provided which reduces or increases the number of cans to be further conveyed, reducing or increasing the number of returning mandrels to this end. A second storage chain 37 is provided after the inside varnishing station 34, 35 and before an outside processing station 38. The outside processing station 38 comprises an undercoating device 39, a printing device 40 and an overlying varnish device 41. In these three devices 39-41, the cans are put each onto a mandrel, are coated and are put onto the chain again to be carried through a drying furnace. When performing this, due to the necessary movements of the cans, substantially the same problems will arise as in inside varnishing.
After outside coating at 38, a third storage chain 42 and subsequently a final shaping device 43 is provided, as, for example, for aerosol cans for forming the can's neck, as well as a packing machine 44.
The conveying conception used in the entire production line is based on conveying by chain conveyors which comprise laterally projecting mandrels in predetermined distances for holding the cans. The cans are aligned one dimension-ally in fixed distances one after one so as to be moved, in average, with the same speed. This substantially rigid can movement throughout the whole plant results in synchronising problems at the processing stations. In order to compensate for local conveying variations due to the operation or its interruption, mechanically expensive compensation or storage devices have to be provided. In addition, the desired period of dwell of the cans within a processing zone has to be determined substantially by the length of the chain within this zone, resulting in an extremely large chain length in the furnaces because of the long drying periods. Due to this chain conveyor concept, linear production lines rigidly constructed will result which need large workshops, and in which all processing 'stations have to be matched to each other. In addition, the expenditures for servicing the conveying chain and the energy loss of the furnaces are very high.
Now, the object according to the invention consists in that tc outline a plant for processing containers of any, particularly non-magnetic, material, which is constructed in a simpler and more flexible way and which involves less expenditure for synchonising. Moreover, the conveying device should be formed in such a manner that transfer to processing stations is facilitated.
This object is achieved by realising the features of the introductory clause in conjunction with the characterising features of claims 1 or 8. In addition, when attaining the object according to the invention, the inventive pallet according to claim 10 was found. Alternative and advantageous embodiments are described by the features of the dependent claims , respectively.
When solving the problem, it was recognised that the drawbacks described above with reference to the prior art originate substantially from transporting the cans on mandrels of the conveyor chains. In the approach according to the invention, by conveying the cans by pallets on moveable conveying surfaces, the flexibility necessary for avoiding synchronising problems in the conveying operation is created. With a constant speed of motion of the conveying surface, such as of the conveyor belt of a belt conveyor, the speed of motion of the cans and, thus, the distance between the cans, can be varied, because some slippage is enabled between the conveying surface and the joining surface of the pallet which engages it. By means of guiding and stop members influencing the movement of the pallets on the conveying surface, accumulation zones for compensating for variations of through-put and transfer zones for providing cans at transfer locations can be formed. The processing stations, in accordance with their processing frequency, take cans to be processed out of an accumulation zone or of a transfer location and pass them after processing to a conveying surface without any synchronisation.
In order to prevent, at least in critical conveying zones, that the joining surface of a pallet disengages unintentionally from the conveying surface, or the can tilts off the pallet, without restricting the relative moveability on the conveying surface, the pallet is formed from magnetizable material, at least in part, and at least one permanent magnet or, optionally, an electromagnet is assigned to the conveying surface within this region so that the pallet adheres to the conveying surface due to magnetic forces. In this way, it is possible that the conveying surface may be oriented in any direction without the cans being released.
Such a possibility of arbitrary orientation is advantageous
tor the transfer to processing stations and, in particular,
during processing in the processing stations.
The pallet comprises a joining pallet surface for engaging the conveying surface, and a connection surface including at least one connection means for connecting the pallet to a surface of the can, the joining pallet surface and the connection surface being substantially parallel. With cylindrical cans having an open end and a can closing wall opposite the open end, in order to attain a preferred orientation of the cans relatively to the conveying surface, the closing wall of the can is connected to the connection surface. In this way, it is warranted that the longitudinal axis of the can is always substantially perpendicular to the conveying surface.
In order to transfer the cans in a horizontal position to a processing station or to a support member, the conveying surface is, thus, oriented substantially in vertical direction within a transfer zone. Due to the arrangement of the magnetically supported pallet onto the can's bottom, the can is freely accessible from the can.'s opening and may be displaced onto a supporting mandrel for outside processing or into a sleeve for inside processing without putting it into a support pan. The use of magnetizable pallets has the advantage that the actuation of the can's movements by pulses of pressurised air can be omitted. Actuation or any displacement in the direction of the container's axis necessary for charging and discharging is preferably done by electromagnetic actuation means. When re-adjusting the production line to cans of another diameter, any exchange of supporting pans is avoided. Only the supporting elements have possibly to be exchanged.
In preferred embodiments of the plant, the can is not introduced into a sleeve for inside processing, but is supported by a magnetic supporting surface magnetically holding the pallet. In order to be able to impart rotational movement to the cans during spraying of the inner varnish, the support surface is, in particular, rotatable. In com-parison with sleeves, the magnetic support surfaces have
the advantage that the do not have to be exchanged when changing to another can diameter, because they may be constructed so as to support cans of different size on pallets of the same size and preferably also for supporting pallets of different size.
Optionally, the cans are moved by a magnetic rotator and/or by stationary or moveable guidances guidingly engaging the pallets into positions opposite the support elements. In case, the movement of the rotator is synchronous with and concentric to the movement of a rotating drum having support elements, the transfer may also be effected onto moving support elements.
In a cleaning station, it is necessary for draining the cleaning liquid that the open end of the cans is downwards directed. This can be achieved without any problem by a magnetic conveyor the conveying surface of which is downwards directed. By replacing the chain conveyors of the prior art by magnetic conveyors, an arbitrary orientation of the conveyed cans is enabled. In addition, the expenditure for servicing the conveyors is significantly lower, and by providing accumulation zones, particularly on belt conveyors, expensive storage chains can be avoided. Due to the new conveying concept, the plants can be constructed in a more flexible manner. For example, processing zones, preferably associated to belt conveyors, which may be laterally or even vertically offset may replace linear production lines. Thus, the plant may be adapted to existing production space which is not possible, or only with a great expenditure, with plants of the prior art.
The conveying device comprises preferably guiding elements which render the containers moved by the conveying surface guidable along any way desired, especially by guiding contact with the pallets, the quiding elements being, optionally, moveable by an actuating device. In this v/ay, separ-ating devices can be provided for distributing the con-
tainers fed to at least two partial lines. The partial lines lead, for example, to processing stations working in parallel. After processing in the stations arranged in parallel, a combining device may enable combining the containers of at least two partial lines. Such processing in parallel would be excessively expensive in plants having chain conveyors. Within the scope of such a flexible construction of a plant, it may be suitable, to combine the furnaces of different processing steps, in order to minimise the heat losses. :
Charging the furnaces is preferably effected by belt conveyors which retain the cans for drying in an accumulation zone within the furnace. Drying is significantly simplified by enabling the cans to be received in the furnaces while standing on the pallets. In particular, the furnace pans become superfluous for drying the inner varnish so that such pans need not to be exchanged when re-adjusting the plant to another can size. In the prior art, a chain leads through the furnace when drying the outer varnish. Such a chain discharges more heat from the furnace than pallets being suitably dimensioned.
The plants according to the invention are not only flexible in their construction, but enable also processing of many differently sized or shaped cans or containers with a minimum expenditure for re-adjustment. By choosing a uniform connection between the pallets and the can's bottom, preferably by selecting the cross-section of the pallets so that it is somewhat larger than the cross-sectional range of at least two current can types, the same pallet can be used for different types of cans. The height of the cans does not matter which is a further advantage in comparison with holding them by mandrels.
In a first zone of the plant, the pallets are connected to the cans which are separated in a final zone while the pallets are returned to the first zone via a pallet return.
Within the framework of the return, pallet cleaning, and, especially, pallet storage, is preferably provided. The same plant may be operated with different types of pallets, e.g. with pallet types of different pallet cross-sections, without any problem. To this end, the pallet store may be constructed so that it can either store all pallets of an individual type in separate zones and/or can convey them co the first zone of the plant, if necessary. The plants according to the invention are not restricted to cans of a certain material. Magnetizable or non-magnetizable metals as well as non-metals, particularly plastics, can be considered. The broad spectrum of uses results, in particular, from the conveyor device which includes magnetic conveyors in conjunction with magnetizable pallets.
The drawings will explain the invention showing embodiments schematically illustrated.
Fig. 1: A plant for processing aluminium cans in accordance with the prior art;
Fig. 2: Flow chart of a plant according to the invention
Fig. 3: Cross-sectional view of a pallet and aluminium can as well as a plan view onto a pallet;
Fig. 4: Cross-sectional view of a pallet and tube as well as a plan view onto a pallet;
Fig. 5: a perspective view of an inside varnishing processing station;
Fig. 6: A plan view onto an embodiment of a magnetizable pallet,- and
Figs. 7-9: Cross-sectional views of pallet.
Figure 2 shows a flow chart, of a plant for producing aluminium cans in accordance with the invention. A press 30 is provided as a first processing station. The raw cans consist of cylindrical sleeve winch comprises a charging opening at: one end and a closing wall at the other end. Ac
least one connecting portion projects from the closing wall which is substantially outwards directed and is, preferably, centrally arranged. Afterwards, the cans are cut to the length desired, are, optionally, brushed, and are provided with a pallet in a raw processing station 31'. The station 31', thus, comprises a palletising device which connects the connecting portion of the can to a connecting surface of the pallet., preferably by introducing and fixing, particularly by a riveting device, the connecting portion into an opening of the pallet.
Optionally, pallets provided with cans may be introduced into a pre-store "45 for small-scale series. A magnetic belt conveyor, which, optionally may also be charged from the pre-store, leads from the raw processing station 31' to a cleaning station 33. The cans are led by means of the pallets on the conveyor through various cleaning zones, such as degreasmg and flushing zones, the conveyor being arranged in such a manner that the cans are held with their container opening downwards before exiting each of the cleaning zone in order to warrant draining of cleaning liquid as completely as possible, and that the cans are held with their container opening downwards when entering, or at least before exiting from, a bath, optionally being provided, in order to enable complete filling of the can interior with cleaning liquid.
A belt conveyor joins immediately to the cleaning zone and includes an accumulating section 46 which retains containers which cannot be passed for a times. The pallets are preferably retained by an actuable retaining means, particularly by a barrier against which the pallets of the containers which are adjacent to the retaining means will prop. The conveying surface passes slidingly below the joining surfaces of the.accumulated pallets.
Upon readiness, the cans are fed from the accumulation zone to the adjoining inside varnishing device 34 by means of a,
preferably magnetic, feeding conveyor, in particular by a rotator, and are received by the latter in rotatable holders that rotate the cans during spraying of varnish about their longitudinal axis while being oriented about horizontally. In plants according to the invention, however, the cans could also simply be transferred and varnished in a vertical orientation. Optionally varnishing could be done without rotation. Since the can opening is freely accessible when conveying by means of pallets, the cans must not necessarily be introduced into a holder of the inside varnishing device, but varnishing can be done directly in the cans standing on the conveying surface together with their pallets, as is represented in Fig. 5. The conveying surface can be moved or may be stopped during varnishing. The only requirement is that at least one varnishing nozzle is arranged to be displaced to the cans. Conveying the cans on magnetizable pallets in accordance with the invention has the advantage that it can be applied both with processing stations of plants having conveyor chains and with processing stations constructed according to the new conveying concept. This means that in an existing plant, for example, the conveyor chain can be removed and conveyance between the old processing stations can be replaced by the conveyor according to the invention comprising preferably pallets and magnetic conveyors. It goes without saying that plants constructed according to the new conveying concept can be formed in a still more advantageous manner.
From the inside varnishing device 34, the cans proceed, preferably on a belt conveyor, to an inside varnish furnace 35' where they are retained in an accumulation zone on the belt conveyor for drying. In order to reduce any heat loss and to prevent the exit of gases which might be set free, the furnace 35' may be shut on its outlet side before filling and may be shut also at its inlet side at the end of filling operation. After drying, the outlet side is opened again so that the cans are further conveyed on the belt, conveyor out of the accumulation on zone within the furnace
35'. In order to further reduce the exit of undesirable gases, gas may be sucked off during exit of cans out of the furnace 35', and may be blown to a purifying stage. Fresh air streaming into the furnace 35' is preferably guided over the exiting cans in such a manner that it enters the furnace in a pre-heated condition. When all cans are out of the furnace 35', the outlet opening is closed again, and the inlet opening is opened in order to carry out the next drying cycle. In this discontinuous drying operation, an accumulating space of at least the size of the accumulating space of the furnace has also to be provided between the inside varnishing device and the furnace 35'.
In order to attain a simple construction and, in particular, -to dry all cans exactly in a uniform manner, it is convenient to use continuously operated pusher-type furnaces. Through such furnaces passes a conveyor belt having preferably a standard width and being loaded with rows of cans in accordance with the belt width from an accumulator-loader. The belt speed is selected in such a manner that the maximum supply of cans can still be passed through the furnace. In order to attain the necessary time of heating or drying, the length of the furnace has to be chosen in accordance with the belt speed. After the furnace, the rows of cans running in parallel, particularly when exiting an accumulator zone can be separated again.
Since the cans must no longer be held on their peripheral surface for varnishing inside, plants are suitable in which an outside coating is effected before coating the inside. In such plants, the cans need no longer be held in their interior after varnishing inside which diminishes the strain of the fresh coating of inside varnish. In order to refrain from holding the cans inside, the cans could be supported, for example by the pallet during processing the outside, and could only be held within a small inner zone at the can opening.
In plants according to the invention, it is possible with little expenditure to perform drying to be carried out after each of three outer coatings within a common furnace assembly 47. The cans pass, preferably on a conveying belt, from a priming unit 19' to a first drying zone or compartment 47a of the furnace assembly 47 and from there to a printing device 40'. From the printing device 40', the cans pass through a second drying zone or compartment 47b to a coating varnishing device 41' and from that through a third drying zone or compartment 47c to a depalletising unit 48. Since the outside coating is made preferably with the cans being held in horizontal orientation it may, optionally, be convenient for simplifying the transfer onto or from the belt conveyors passing through the drying zones to construct them as magnetic conveyors having substantially vertical conveying surfaces at least in the zones of transfer. Drying may be done either continuously in tunnel furnaces open at both ends, or, preferably, discontinuously, as described with reference to the inside varnish furnace 35'.
Putting the cans onto holding mandrels of the outside coating devices 39', 40', 41' can, optionally, be avoided by holding the cans on the pallet and only inside the edge of the can's opening during coating.
The depalletising device 48 comprises a separating means for separating each pallet from the can, in particular for removing at least part of the connecting portion which projects from the connection surface connected to the pallet. For severing rivet connections, a cutter is provided, for example, which cuts the rivet head off from the side of the pallet averted from the can. By a stop means engaging the pallet can be prevented that part of the pallet might be cut off. After cutting, a separating device will guide both parts ts a further guidance.
The cans without the pallets are processed further in a subsequent final shaping device 43, particularly by pres-
sing the can's bottom into the desired shape, and, optionally, by completely removing the connecting portion. At the can opening, a neck is formed for receiving a valve. In plants which perform shaping of the bottom already in the raw processing stage, pallets should be used which meet the shape of the bottom.
From the depalletising station 48, the pallets are passed over a pallet return 49, preferably via an at least partially magnetic belt conveyor, via a pallet cleaning device 50, as preferred, and/or via a pallet storing unit 51 to the palletising station 31'. Besides the pallets just returning, at least as many pallets have to exist, as cans are being processed.
Fig. 3 shows a preferred pallet 107 for a can 103 where shaping of the bottom is done after depalletising. The pallet 107 has a joining pallet surface 122 for engaging a conveying surface, and a connecting surface 121 including at least one connection means for connecting the pallet 107 to a can's bottom surface 130, the joining pallet surface 122 and the connecting surface 121 being substantially parallel to each other. In a preferred embodiment, the joining pallet surface 122 is annular, and the connecting surface 121 is disk-shaped. The two surfaces 121 and 122 are spaced from each other over a desired distance by a, preferably cylindrical, spacer surface 131. The spacer surface 131 extends preferably from the inner edge of the joining pallet surface 122 to the outer edge of the connecting surface 121.
The connection means comprises at least one, preferably central, connection opening 117 into which a connecting portion 132 of the can wall 130 may be fixed, optionally by friction, but preferably in a positive manner, in particu-lar by riveting. By the fiveting operation, the free end of the connecting portion 132 is deformed Laterally beyond the edge of the connection opening at the side of the connec -
ting surface 121 which is averted from the can. In order that the rivet connection be firm against any rotation even after any material deformation caused by temperature, an elastic load is preferably built up by spacing the connecting surface 121 and the can wall 130 by spacers 133 within the region of the connecting portion 132. Preferably at least three ribs are provided symmetrically arranged around the connection opening 117. When riveting, the distance between the pallet 107 and the can 103 is somewhat reduced by an elastic deformation of the container bottom and/or of the connecting surface 121. The remaining distance is chosen in such a manner that the can's surface 130 can further be flushed.
At the outer edge of the joining pallet surface 122, a lateral contact surface 134 is provided being substantially perpendicular to the joining surface 122 and extending from the joining surface 122 towards the connecting surface 121. The pallets will contact both guiding elements and each other into guiding and spacing contact via this contact surface 134.
The pallets for receiving cans are dimensioned in such a way that the can's cross-sectional dimensions or diameters are in a range between the cross-sectional dimensions or diameters of the spacer surface 131 and of the contact surface 134. This warrants that during printing the printing roll can extend beyond the lower edge of the can, but the cans are prevented from contact with each other. It is particularly important immediately after the outside processing that the cans are conveyed free of any contact with each other, because in this way damaging the still fresh coating is prevented. In order to be able to receive all current cans by only three pallets differently sized, the pallets are dimensioned, for example, for the following ranges of diameters: 22-25 mm, 35-53 mm and 53-66 mm.
Openings 118a in the connecting surface 121 improve the ability of the can wall 130 to be cleaned, and, in conjunction with openings 118b in the joining surface 122, reduce the weight of the pallets and, thus the amount of heat discharged from the furnaces by the pallets. In order to manufacture the pallets in a cost efficient way, they are stamped out of magnetizable steel and are shaped preferably by deep-drawing as desired.
Fig. 4 shows a pallet 107' constructed in an analogous manner to pallet 107 for tubes 103'. Preferably a threaded portion 132' is used as a connecting portion. In the embodiment shown, a beading of the free end of the threaded portion 132', which results from a pressing operation, protrudes outwards beyond the connection opening 117' so that the tube 103' is fixed to the pallet. When separating tube and pallet, this beading has to be removed. In a preferred embodiment of the pallet 107', at least one, in particular elastic, locking device is provided in order to avoid any necessity of supplementary machining the threaded portion 132'. To ensure that this device engages the tube 103' in a simple locking operation, a peripheral groove is made in the portion 132', e.g. before cutting the thread, preferably at the end of the threaded portion facing the tube. The tube-side part at least one locking device, which can be laid over the thread in an press-fitted condition, engages the groove so that the tube is fixed to the pallet. In order to ensure a good perpendicular orientation of the tube 103' with respect to the pallet 107', the pallet comprises, preferably three, contacting zones which are engaged by corresponding zones of the outer surface of the tube when the tube is fixed to the pallet by the locking device. The locking device comprises preferably three elastic tongues.
Fig. 5 shows schematically an inside varnishing station comprising a spraying apparatus 1 including spraying nozz-
to the interior of the cans 3 of non-magnetic material such as aluminium. Subsequently to spraying by means of the nozzles 2, the cans are passed to a drying chamber 4 which is formed, for example, by a tunnel furnace. The construction may either be such that that the cans are discharged at the other end of the drying chamber (not shown), or they are discharged to the left side again (with reference to Fig. 5) by the lower belt portion of a belt conveyor 5 in a manner still to be described. In such a case, it would be possible to provide processing devices also on the side of the lower portion of the belt conveyor 5, such as a further spraying device.
In order to hold the cans 3 securely in their place on the belt 5, the belt conveyor 5 is formed as a magnetic conveyor known per se either by incorporating small permanent magnets into the belt 5 which move together with the latter, or by arranging stationary magnetic plates 6 at the lower side of the belt 5 which, optionally, co-operate with electromagnets located on them or are permanent magnetic too .
To hold the non-magnetic cans 3 fixedly on the belt 5, even if, for example, it has to be guided in upward direction or if the cans should remain on the lower portion of the belt 5, magnetizable pallets 7 are distributed over the belt. Thus, these pallets will co-operate with the magnetic plates 6, the latters having to be arranged closely to the lower portion of the belt 5, if this portion shall be formed to entrain the cans. On the other hand, the pallets 7 could also be fixed to the belt 5. Preferably, however, they are displaceable on it, because it facilitates manipulation, as will become apparent from the following.
In. this way, a second belt conveyor 8 may be provided and
may, in principle, be also formed as a magnetic belt con-
veyor which extends parallel to the belt conveyor 5 or under an angle to the belt conveyor 5. In order to move the
cans 3 from the belt conveyor 8 to the belt conveyor 5, deviation surfaces 10 are provided which are inclined with respect to the direction of movement (arrow 9) of the belt 8 and which, preferably, do not engage the cans 3 (to conserve their outer surfaces), but the displaceable pallets
While the representation of Fig. 5 shows only one can 3 after the other, the cans 3 may, within the scope of the invention, by arranged in pairs (or even in a greater number) on the respective belt 5 or 8 so as to increase the productivity. In such a case, several processing units have, of course, to be arranged side by side. Then, the deviation surfaces could be arrow-shaped including a tip inmidst the width of the belt 8 instead of having a single inclination so as to deviate the cans to the left and to the right side (with respect to the direction of movement 9). Furthermore, it is not necessary to provide belts 5 and
8 of the same type as a conveying means; for example, one
belt may have assigned a lateral rotator to which the re
spective can is displaced to perform a revolution on the
rotator, e.g. for varnishing, in order to provide the time
for this procedure without having to stop the respective
belt conveyor and to operate it in an intermittent fashion,
the deviation surfaces could, for example, be moved in a
controlled manner into the path of the belt conveyor, e.g.
by means of a rack and pinion drive or by a fluidic unit,
such as a pneumatic cylinder, instead of being stationarily
arranged (as shown in Fig. 5 and, for example, fixed to the
frame, not shown, of the belt conveyor 8) so that then even
a plurality of subsequent deviation surfaces may alternate
ly project into the path of the belt conveyor or are with
drawn from it to displace the cans 3 to a succession of de
vices, such as rotators. The cans could be removed from
such rotators either by manipulators or by deviation sur
faces, e.g. being d i s p 1 a ceble towards the respective ro-
tator, which move the pallets 7 together with the cans 3
onto the (or another) belt . A futher possibility consists
in that the pallets 7 themselves are formed as rotators and to drive them, for example, at their periphery as will be explained below with reference to Fig. 7.
It has already been mentioned above that the deviation surfaces 10 may be displaced in a timed manner in accordance with the arrival of cans 3 at the respective location. To this end, optionally, an exact control may be used, an embodiment of which being shown in Fig. 5. Optionally, the same applies for the actuation of processing units such as the spraying device 1. The same shows two cylinder units 11 engaging a support 13 by straps 12. Supply of spraying liquid, such, as varnish, is effected through at least one hose not shown connected to the support 13, or through a hose-for each nozzle 2.
In order to determine the presence of a can below the respective nozzle 2 (a single one or a whole battery of such nozzles may be-provided), a sensor 14 is arranged which may be constructed in any manner know to those skilled in the art. In the representation of Fig. 5, it is formed as a light barrier comprising a source of light 15 and an opposite light-electric transducer 16 which, however, could also be situated on the same side of the belt conveyor 5, the transducer 16 receiving, for example, light reflected from the cans 3. The latter arrangement will result in a particularly clear signal at a certain time due to the round periphery of the cans.
On the other hand, one is not bound to opto-electric or other radiation sensors in selecting the sensors, since the material of the cans would, in general, also provoke a response of an inductive or capacitive sensor. In any case, the output signal of the respective sensor 14 or the transducer 16 will serve to control appropriate actuating units, such as the cylinder 11.
The use of magnetizable pallets 7 involves, in general, the use of a relative heavy material. Therefore, it is preferred, if the respective pallet 7, preferably being circular for the intended purpose, has at least one opening permeating its thickness and interconnecting the two main surfaces, as shown in Fig. 6, which reduces the weight, on the one hand, but may also serve additional purposes, on the other hand, as will be still explained. In the embodiment of Fig. 6, apart from a central opening 17, still further openings 18 are provided. These openings 17, 18 may serve as recesses, i.e. as a holding means, for receiving protrusions of the cans, such as a lower can rim 19 (Fig. 8), but a reversed arrangement is also possible in which the pallet" has a protrusion which enters a recess of the can 3 or surrounds a rim thereof. This latter variant will, however, not be preferred, because it is, in general, more favourable for completely processing the outer surface of the cans, if the same is freely accessible. This is also the reason for the special constructions in accordance with Figs. 8 and 5.
If, as mentioned above, a drive for the pallets is desired, their cross-section may be chosen according to Fig. 7 where a pallet 7a is illustrated having a V-groove 20. With this V-groove 20 two friction disks appropriately formed and arranged at the periphery, e.g. under an angle relatively to a central axis A, could, for example co-operate. Theoretically, also a belt drive would be conceivable, but such a belt had to be put around the circumference of the respective pallet 7a. However, it has to be understood that for rotatively driving the pallets also other constructions or their peripheral surfaces, such as a more or less smooth or a toothed peripheral surface (for the engagement of a pinion) are, actually, possible. Moreover, the central opening 17 could be employed for insertion of a driving shatt, but this will, in general, be less practicable. by the way, in the embodiment or Fig. 7 it should be noted,
that the central poening 17 may be dimenisoned so largely
that the pallet 7a (likewise as the pallets 7b and 7c to be discussed later) is annular in shape.
Another purpose of such a V-groove 2 0 could be to allow engagement of a deviation surface 10 (see Fig. 5). Such deviation surfaces should suitably have a thickness which corresponds to the thickness of the pallet 7a in maximum so as to ensure not to leave scratches on the can surfaces. Of course, the deviation surfaces may be even arranged at the level of the respective piece good, if it has not so sensitive surfaces, as is the case with the cans 3 shown, in which case the pallets may optionally be fixed to the respective conveyor.
In Fig. 7, a flat embodiment of the pallet 7a can be seen which, accordingly, will have a main or connection surface 21 facing the can (which is supposed to be herein-above) and another main or joining surface 22 facing the magnetic conveyor (5 or 8) .
As is particularly shown in Fig. 8, projections 23 may protrude as spacers from the plane of the upper main surface 21 and may leave aerating channels shown in dotted lines between each other so as to allow access of hot air to the lower side of a can, tor example within the tunnel furnace 4.
As has been mentioned, free accessibility to the peripheral surface of the respective can 3 will be generally important. Optionally, the pallet 7c has a smaller circumference than the can 3 for this reason, as is shown in Fig. 8.
Another approach for a pallet 7c is shown in Fig. 9. In order to increase the stability of the (relative light) can 3 on the pallet, its lower rim 19a may have an outer thread which is Screwed into an inner thread 26 of the pallet 7C In this embodiment, the accessibility of the peripheral surface of the can 3 is endured in that the pallet has a
convex upper main surface 21a which also extends substantially in a plane parallel to that of its joining pallet surface and projects beyond the periphery of the can by a distance a, thus, improving its stability. The convex main surface 21a may be provided with spacers by a corrugation (see the dotted concave portion 27) to improve the access of air.
Numerous modifications are possible within the scope of the invention; for example, the openings 17 and may serve and may be constructed or arranged to allow insertion of processing devices. Although a magnetic belt conveyor is preferred, also other conveyors are conceivable which- co-operate with magnets, as has already been mentioned. Moreover, a pallet could be designed to receive a plurality of piece goods 3, e.g. of a pair of cans 3, although this will, in general, not be preferred.
It goes without saying that features of the embodiments described could arbitrarily mutually be combined.
We Claim :
1. A plant for processing containers having a cylindrical sleeve, a charging opening at one end of the sleeve and a closing wall at the other end of the sleeve, particularly of a. non-magnetizable material, such as aluminium, said plant comprising processing stations for carrying out processing steps, such as cleaning and/or coating and/or drying, and conveyor means for conveying said containers to a processing station, in it or from it, characterised in that the conveyor means comprises at least one magnetic conveyor and a magnetizable pallet to be connected to at least one container, a joining pallet surface of said pallet engaging a moveable conveying surface of said magnetic conveyor and being held on said conveying surface by said magnetic conveyor by means of magnetic forces.
2. Plant as claimed in claim 1, characterised in that at
least one of the following characteristics is provided :
a) said conveyor means comprise at least one, preferably magnetic, belt conveyor which forms an accumulation zone before a processing station, thus, retaining container which cannot be passed at times, the containers being retained within said accumulation zone by retaining means, which are preferably actuable, in particular by a barrier onto which the pallets of the containers adjacent to said retaining means abut, while said conveying surface slidingly passes below the joining pallet surfaces of the pallets;
b) said conveyor means comprise at least one guiding element for guiding said containers along a desired path, m part- icular by contacting said pal-1ets , said guiding elements optionally being dis -placeable by actuating means;
c) said conveyor means comprise at least one separ-
ating means for distributing the containers fed towards it to at least two partial lines, preferably to at least two belt conveyors;
d) said conveyor means comprise at least one combining means for combining containers from at least two partial lines, preferably from at least two belt conveyors;
e) at least two processing stations for carrying out the same processing step are arranged in parallel.
Plant as claimed in claim 1 or 2, characterised in that for transferring containers to a processing station which includes support members, such as mandrels for outside processing or sleeves for inside processing, or for removing them, magnetic conveyor means are provided, the conveying surface of which being substantially vertical to an axis of said support members so that the axis of the containers, which is substantially perpendicular to said joining pallet surface, is aligned or parallel to said axis of said support members, and the respective container can be fed to said support member or is removed therefrom by displacement in the direction of said container axis by a mechanical, pneumatical or electromagnetic actuation device preferably acting onto said pallet.
Plant as claimed in any one of claims 1 to 3, characterised in that for transferring containers to a processing station at least one, preferably magnetic, rotator is provided, and, optionally, at least one fixed or moveable guiding element which preferably contacts said pallets for guiding them.
Plant as claimed in any one of claims 1 to 4, characterised in that at least one processing station for drying containers is formed as a furnace comprising a furnace charging, preferably magnetic, belt conveys: means, said belt conveyor means comprising an accumul-
ation zone at least within said furnace wherein said containers are retained during drying, and/or that at least one of the following characteristics is provided :
a) said furnace comprises shutting means at least in the region of its outlet, preferably also in the region of its inlet, retaining the pallets and the containers on said belt conveyor means, and/or reducing heat losses;
b) a sucking device for sucking fresh air into the furnace is provided, and is preferably formed to suck fresh air over dried exiting containers to pre-heat it;
c) at least two furnace compartments for different processing steps are adjacent to each other or formed as a common furnace for reducing heat losses by radiation.
Plant as claimed in any one of claims 1 to 5, characterised in that at least one processing station for cleaning or washing comprises magnetic cleaning conveyor means, which include preferably belt conveyor-means, which passes the containers through at least one of different cleaning zones, such as a degreasing and a flushing zone, said cleaning conveyor means being arranged so that said charging openings are held in downward direction before said containers leave the respective cleaning zone to ensure draining of a cleaning liquid and/or are held in upward direction at least before said containers leave a cleaning zone which includes a cleaning liquid to be filled into said containers to enable filling the interior of the containers with said cleaning liquid.
Plant as claimed in any of claims 1 to 6, characterised in that said processing stations and conveyor means comprise at least one of: the following charac-
a) a palletising station in which said closing wall, which has, in addition, at least one connecting portion projecting outwards substantially in the direction of the axis of the container, and being preferably centrally situated, of each container is connected to a pallet, and which comprises, in particular, a riveting device guiding said connecting portion through a connection opening in said pallet and then pressing said connecting portion broad at that side of said connection opening which is averted from said container;
b) a depalletising station which removes at least one section of a connecting portion of the processed containers, which, in particular, projects out of a connection opening of a pallet in a rivet-like manner, preferably by cutting means, and which enables separate conveyance of said pallets and said containers by means of a separating unit;
c) pallet cleaning means, for cleaning pallets separated from any container;
d) pallet storing means for storing pallets separated from any container and being not in use;
e) return conveyor means, preferably comprising at least partially magnetic belt conveyor means, for returning pallets separated from any container to a palletising station,
A conveying apparatus for conveying containers by means of a magnetic conveyor having magnetic means and a moveable conveying surface, characterised in that
the apparatus comprises a number of magnetizable pallets to be connected to containers to be conveyed, in particular of non-magnetizable material, such as aluminium, and having a joining pallet surface to engage said conveying surface of said magnetic conveyor, said magnetic means rendering said pallets togetner with the containers supportable on said conveying surface
by means of magnetic forces
9. Conveying apparatus as claimed in claim 8, characterised in that the magnetic conveyor is either
a) formed as a belt conveyor comprising permanent magnetic elements, preferably being arranged at the side of the belt opposite said pallets, or
b) formed with said moveable conveying surface and
at least one permanent magnetic or electromagnetic element.
10. A pallet for a conveying apparatus as claimed in claim
8 or 9 and/or for a plant according to anyone of
claims 1 to 7, characterised in that the pallet com
prises a joining pallet surface for engaging a covey-
-ing surface, and a connection surface including at least one connection means for connecting the pallet to a surface of a container, the joining pallet surface and the connection surface extending in substantially parallel planes.
11. Pallet as claimed in claim 10, characterised in that
at least one of the following characteristics is pro
a) the pallet has an annular joining pallet surface, a disk-like connection surface and a, preferably-cylindrical, spacer surface which interconnects said joining pallet surface and said connection surface in a desired distance, the spacer surface extending preferably from the inner edge of said joining pallet surface to the outer edge of said connection surface;
b) connection means comprise at least one, preferably central connection opening into which a connecting portion of a container may be fixed, optionally by friction, but preferably in a positive manner, in particu1ar by riveting;
c) at least three projections, optionally formed as
ribs, which are arranged symmetrically around a centre, in particular around a, preferably central, connection opening, and which, when said connection surface joins a surface of a container, keeps a free space open and, optionally, render feasible some tension of the connection d) at the outer edge of a joining pallet surface, a contact surface is formed perpendicularly to said joining pallet surface and extends from said joining pallet surface towards a connection surface.
12. A plant for processing containers having a cylindrical sleeve substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
13. A conveying apparatus for conveying containers substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
14. A pallet for a conveying apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
|Indian Patent Application Number||2055/DEL/1996|
|PG Journal Number||13/2009|
|Date of Filing||18-Sep-1996|
|Name of Patentee||CREBOCAN AG,|
|Applicant Address||HOFACKERSTRASSE 6, CH-9606 BUTSCHWILL, SWITZERLAND,|
|PCT International Classification Number||B65G 21/20|
|PCT International Application Number||N/A|
|PCT International Filing date|