CONVEYOR FOR FILLABLE CONTAINERS

Abstract: A conveyer in which, attached to the longitudinal connective structure with slack, such as a chain, there are successive transverse bar-like structures (2) with arranged widthwise across them a row of openings for containers or the like to be transported to different processing stations, the conveyer's line of movement running through these stations. Parallel to the conveyer's direction of motion, is fitted a positioning device (3), separate from the connective structure with slack, arranged to sequentially grip the bar (2) traveling from one station to another. Utilising the temporary coupling of members (8, 12) fitted onto the bar (2) and the positioning device (3), the positioning device (3) accurately positions the bar (2), at least longitudinally, in its correct place at the processing stations.

Description: CONVEYOR FOR FILLABLE CONTAINERS This invention relates to a conveyer with which e.g. drink cartons are conveyed and positioned accurately for various processes, such as sterilisation, filling and closing, along an automated process line. In the food industry, many different applications are utilised to fill cartons, bottles and the like in a continuing process, with e.g. liquids, for consumer use. The methods also apply to the pharmaceutical industry. In the process, a conveyer, in which the cartons to be processed and filled have been placed, transports the cartons from one processing station to another. The processing may include such stages as sterilising, filling and closing. The essential point is that the cartons are placed accurately at the points in the processing stations where the respective processing is to take place. The cartons arrive at the beginning of the conveyer, after which they are placed by an appropriate method on the conveyer, which usually transports the cartons in stages in such a way that either a single container or a row of containers arrives at a station. After the processing, the conveyer executes the next stage. To ensure trouble-free processing, the containers must rest firmly and accurately in their place on the conveyer. In known methods, the containers are placed in an upright position in true-to-size openings or rings and the containers are to be held firmly in their place throughout the entire process. European Patent 0 479 010 B1 discloses a method with a rotatable table of rigid construction and radially placed rows of openings or cavities for the containers, which as the table rotates, are transported sequentially from station to station. In principle, a rigid table construction of this kind is good, as it has no slack. The operating accuracy is dependent solely on the precision of manufacture of the table and the accuracy of the driving device. The disadvantage of a construction of this kind is, however, that little room is left for the auxiliary machinery, such as the devices for sterilising, filling and closing, as they must be fitted within and above the circumference of the table. In a horizontally rotating construction, the container openings that are closest to the centre of the table are close together in the circumferential direction, which complicates the positioning of the machinery. In practice, it is easy to construct the conveyer in such a way that the containers stop accurately at the respective stations along the conveyer, but the problem is the inaccuracy of the sequentially advancing conveyer, which causes inaccurate positioning of the containers at the processing station after a transfer sequence of the conveyer. Traditional constructions involve a conveyer in which crosswise bars with true-to-size openings for the containers are attached to a pair of continuous looped chains. A driving device advances the conveyer sequentially in such a way that the row of containers progresses from one station to the next. In a construction of this type, the chains and driving devices always have slack, which causes problems for the filling process. In terms of space utilisation, the preferred embodiment is a conveyer which incorporates container bars carried e.g. by a pair of chains functioning as a continuos loop in such a way that, at one end of the conveyer, the containers are fed into the conveyer bars, and at the other end, the processed containers are removed from the conveyer by a separate unloading device. The advantage of this construction over the circular rotating table is the increased freedom of choice in determining the number of containers to be processed simultaneously, i.e., the number of openings per conveyer bar. The disadvantage of the construction is that a conveyer that is predominantly chain driven will always have slack in both the chains and the driving devices. It is virtually impossible to make a conveyer of this kind to operate with the degree of precision required by the process. The purpose of this invention is to eliminate the above-mentioned defects, and to present a conveyer that combines the advantages and precise positioning at the respective stations of the loop-type conveyer. This is accomplished by fitting to the conveyor, in addition to the driving device, positioning equipment for placing the container bar accurately in the required position, as dictated by the location of the processing stations. In principle, the equipment according to the invention functions as follows. On the chain conveyer forming a continuous loop, crosswise bars with openings such as holes in which the containers to be handled are held firmly in place, are fitted at appropriate intervals. At one end of the conveyer, the containers are fed onto the conveyer by a feeding device. At the other end of the conveyer, there is a container unloading device. The bars have several, e.g. from three to eight openings for containers. The chain conveyer transports the container bar with its row of containers sequentially through the container processing stations. Such stations include, e.g. sterilisation, filling, closing, etc. On each side of the conveyer, parallel to the conveyer's direction of movement, is a separate positioning device, such as a rod rotating around its own longitudinal axis, with fixed positioning members, such as pegs, positioned at intervals equal to the distance from one processing station to the next. By rotating the rod around its longitudinal axis, the pegs fit into counterparts, which can for example be slots, at either end of the container bars, thus locking the bar accurately in both lengthwise and crosswise direction. At one end, the rods are attached by bearings to pushbars which, driven by a servomotor, accurately move the rods back and forth parallel to their longitudinal axes, a distance equal to the distance from one processing station to the next by pushing the conveyer forward to the next processing station by means of the pegs turned into the corresponding slots. After this, the rods rotate and free the container bars, and the servomotor pulls the rods back to their initial position. The sequential advancement of the chain conveyer is thus effected by the servomotor. When the container bar has advanced through all the processing stations, a separate unloading device will execute the removal of the containers from the conveyer at the discharge end of the conveyor. The distinguishing characteristics of a conveyer according to this invention are expressed in detail in Patent Claim 1. The foremost advantages of the invention include the freely changeable width of the conveyer, whereby a large number of containers can be processed simultaneously. The length of the conveyer does not limit the number or size of the processing stations, and thus the whole process can be completed on a single conveyer. The most important factor is the accurate positioning of the row of containers at the processing station, hence making the process less susceptible to malfunction. In the following, the invention is described more precisely with the help of the attached drawings, of which Figure 1 is a perspective drawing of one half of the chain conveyor, depicting only the points relevant to the invention, Figure 2 is a cross-sectional drawing of a part of the conveyer perpendicular to its length, and Figure 3 shows the principle of the conveyer as seen from above. The conveyer described in more detail in the following is used in a process line, in which unclosed containers with bottom and side walls are moved below different processing stations. At the least, the process line includes consecutive stations for filling and closing with a lid, but possibly also sterilisation and feeding of protective gas into the containers prior to closing with a lid. The conveyer is particularly suited to the food industry for processes of sterilising and filling paperboard and plastic containers, e.g. aseptic filling lines for tubular or conical beverage containers made of liquid packaging board. Figure 1 is a longitudinal section of an application of the invention in which the looped chain 1 of the conveyer is fitted with container bars 2 at intervals equal to the distance between the processing stations. At both sides of the container, there are turning rods 3, which are rotatingly attached to the pushbars 4 by bearings. The motion of the accurately positioning driving device, servomotor 5, fixed between the pushbar and the conveyer body, is imparted by the pushbar 4 to the turning rod 3. The turning rod is rotated around its longitudinal axis by a member which may comprise simply the lever 6 and driving device 7 attached to the pushbar 4, as illustrated in the drawing. The turning rod 3 has an appropriate number of positioning members 8, represented in the drawing as sidewards projecting pegs 8. When the operation of the machine starts, the driving device 7 rotates the turning rod in such a way that the positioning pegs are turned to fit into the counterparts 12, such as slots at the ends of the container bars 2, the slots being of such a shape as to ensure minimal clearance between the peg 8 and the slot 12 when the peg is pushed home into the slot. Since the other side of the conveyer is equipped with a similar construction, with the pegs 8 turning toward the container bar 2, the pegs 8 will accurately determine the position of the container bar 2. After this, the servomotor moves the conveyer an accurately determined distance to the next processing station. The container bar 2 with the containers 10 resting in their respective openings 9 remain firmly in their correct places for the duration of the processing. Then, the driving device 7 rotates the rod 3 in such a way that the pegs 8 turn out of the slots 12. The servomotor 5 then returns the rods to their initial positions and the sequence is ready to start again from the beginning. Hence, the back and forth moving turning rods 3, driven by the servomotor 5, effectively constitute the mechanism that moves the conveyer forward. Figure 2 is a cross-section of the conveyer, showing the second chain 1 of the pair of chains. The container bar 2, attached to the chain, contains openings 9 for holding the containers in place. Around the circumference of the openings, there are tubular rings for accurate positioning of the containers in relation to the bar 2. If the containers are conical, also the rings are conical. Figure 2 also depicts the guide 13 which enables the turning rod 3 to rotate, and limits its longitudinal movement. Figure 2 shows a situation where the positioning peg 8 is turned into the container bar slot 12. The broken line in Figure 2 depicts the position of the peg 8 when turned out of the slot 12. The slide rail 11 holds the container bar accurately in the correct upright position. The slot 12 may be located as illustrated in Figure 2, in the projecting element 2a made of plastic etc. attached to the side of the actual bar 2. In Figure 2, the projecting element 2a is positioned below the level of the actual bar 2 and attached to stays running downward from the sides of the bar, the projecting element 2a resting on the slide rail 11. The construction of the container bar 2 may also include supports below the openings 9, for the bottoms of the containers. The position of the container bar in relation to the length and width of the conveyer is thus determined by the protruding element 8 and the vertical position by slide rail 11. The servomotor 5 must be such as to move the rods 3 precisely the correct distance from one processing station to the next, i.e. the stroke length must be accurately adjustable. It is obvious to a person skilled in the art that the arrangement of the invention may be carried out in many ways. For instance, the container bars 2 may be exchangeable, and the slot 12 for the peg 8 does not necessarily have to be part of the container bar 2, but it may be attached to the chain conveyer by some other method. The advantage with an exchangeable container bar construction is that the bars 2 can be replaced with new ones already shaped to conform to the new containers. The conveyer can also be constructed in such a way that a separate driving device executes the sequential advancement of the container bars between the processing stations, where the turning rods 3 along with the positioning pegs 8 merely position the container bars accurately for the processing. In such a case, the guide gear (e.g. a cog wheel) of the chain 1 , which guide gear is freely rotatable during the positioning by the positioning devices, is connected to a stepping motor to move the conveyer sequentially by means of the chain 1. The chain 1 has sufficient slack for final accurate positioning. In this construction, the back and forth movement of the turning rods 3 is not needed, and thus the servomotor 5 is not required. The shape of the slot 12, into which the positioning peg 8 turns, is such that the mouth of the slot is larger than the diameter of the peg, in which case the peg will easily find its way into the slot 12, which again narrows toward the end to conform to the tolerances of the peg, whereby the peg 8 positions the slot 12 and, with it, the bar 2, with great accuracy. At the bottom of the slot 12, there can be a clearance between the peg 8 and the bar in the direction of movement, since the advancing movement of the turning rod 3 forces the peg against the edge of the slot in such a way that at the end of the advancing movement there is no clearance. Likewise, when the pegs are used for positioning only, the slot 12 can be shaped in such a way that the peg will position the container bar accurately in the direction of movement. The construction may also be made such that the turning movement of one of the turning rods 3 is limited, so that the pegs 8 accurately position the bar 2 to one side widthwise, with the pegs 8 of the other turning rod 3 pressing the bar 2 from the other side. The rotating movement of the other turning rod 3 must be made capable of some degree of flexibility. Figure 3 shows the conveyer from above, with the longitudinal back and forth movement of the turning rods 3 and the pushbar 4 represented by arrows. The conveyer structure is symmetrical with respect to the longitudinal centre line. As shown in Figure 3 there are six adjacent container openings per container bar. The positioning members 8 are at such distances from one another that during a positioning sequence, there is a positioning member 8 in contact with a container bar 2 at each processing station. It is possible that at some point where the container bar is positioned, there is no processing station and there may be "empty stations" along the way, with no need for accurate positioning and positioning equipment. However, certain longitudinal sections of the positioning equipment may be fitted with positioning members at intervals equal to the distances between the container bars 2, to accommodate a possible relocation of processing stations at this section, or the adding of new processing stations at the "empty stations". The parts of the positioning device 3 may be in contact with the bar 2 throughout the duration of processing at any particular station. Upon completion of the processing, the positioning device 3 executes the transferring movement. Alternatively, the positioning device 3 may release the bar immediately after the bar has been positioned. For those skilled in the art, it is obvious that the kind of a positioning system represented in the invention can also be applied to conveyers other than those with chain structures; in general, it can be applied to all loop- construction conveyers with slack in the direction of movement. The invention can also be applied to other rectilinearly advancing conveyers with consecutive transverse bars. The advantage of the loop construction is that after a passing below the conveyor, the bars 2 come back to the initial station on the upper part of the conveyor, where the transfer of new containers occurs. Furthermore, the invention is not limited to using pegs and slots as the positioning members. Other members of comparable applicability for positioning the container bars may also be utilised. A simple embodiment involves placing the turning rods 3 on the sides of the conveyer, but, depending on the construction, they may also be placed elsewhere. In such a case, a single turning rod 3 may be sufficient. The driving devices 5 and 7, which effect the positioning movement, may be pneumatic driving devices. In the above, the positioning has been defined as the final stage of the push motion of the turning rod 3, but a pulling motion may equally well be used as the positioning motion. The advantage of a construction according to the invention over, e.g. a circular rotating table is that there can be more consecutive processing stations without causing problems of space, and, owing to the rectilinear motion, the distance from one processing station to another is equal on the line of travel of each individual container, and the construction of the processing line is simpler and more compact.

Claims: Claims: 1. A conveyer in which, attached to the longitudinal connective structure with slack, such as a chain, there are transverse bar-like structures (2) with across its width a row of openings for containers or the like containers to be transported to different processing stations, the conveyer's line of movement running through these stations, characterised in that parallel to the conveyer's line of movement, is fitted a positioning device (3), separate from the connective structure with slack, arranged to handle the bar (2) travelling sequentially from one station to another, and, utilising the temporary coupling of members (8, 12) fitted onto the bar (2) and the positioning member (3), to accurately position the bar (2), at least longitudinally, in its correct place. 2. A conveyer according to claim 1 , characterised in that the positioning device (3) is an elongated member, located parallel to the conveyer's longitudinal line of travel, fitted with members protruding to the side, such as pegs (8) which are arranged to be coupled temporarily with their counterparts in the bars (2), such as slots (12). 3. A conveyer according to claim 2, characterised in that the positioning device is a turning rod (3), carried by bearings to enable rotation around its longitudinal axis, fitted with protruding members, such as pegs (8) which, upon rotation into their counterparts (12), such as slots, in the bars (2), position the bar accurately. 4. A conveyer according to a prior claim, characterised in that there is a positioning device (3) on either side of the conveyer. 5. A conveyer according to a prior claim, characterised in that the positioning device (3) is arranged to transport the bars (2) sequentially from one processing station to another and to position the bar (2). 6. A conveyer according to claims 4 and 5, characterised in that the turning rods (3) on both sides are rotatably supported by bearings mounted on a single pushbar (4), to which is fitted a driving device (5) arranged to accurately move the rods (3) longitudinally the distance from one processing station to another. 7. A conveyer according to any of prior claims 1 - 4, characterised in that a separate driving device for the conveyer is arranged to transfer the bars (2) sequentially from one processing station to another, and in that a positioning device (3) is arranged to carry out the accurate positioning of the bars (2). 8. A conveyer according to any of prior claims 3 - 7, characterised in that the protruding members, such as pegs (8), are arranged to turn at the moment of positioning into their counterparts, such as slots (12), in connection with the bars (2), the width of the slots being greater at their opening, e.g. greater than the diameter of the pegs (8), and the clearance between the peg (8) and the slot (12) or the like being smaller at the bottom end. 9. A conveyer according to a prior claim, characterised in that the edges of the bars (2) rest on sliding rails (11 ) which are arranged to position the bars (2) vertically. 10. A conveyer according to claim 9, characterised in that the bar (2) is fitted with a projecting element (2a) which is supported by the sliding rail (11) and is equipped with a counterpart (12), such as a slot, for the corresponding member (8) on the positioning device (3).

Inventors: MYKKAENEN ENSIO, MYKKAENEN, ENSIO
Applicants: MYKKAENEN ENSIO, UPM KYMMENE CORP, MYKKAENEN, ENSIO, UPM-KYMMENE CORPORATION
Application year: 1999
Main classification: B65G17
IPC codes: B65G17