CONVEYER SYSTEM WITH VARIABLE SPACING BETWEEN THE CARRIER UNITS

Abstract: In a cartonizing machine articles are arranged in groups in trays (8) passing along a feeding station further to and through a loading station (10), in which the articles on the successive trays are pushed transversely into respective carton members conveyed with a specific mutual spacing (P). The mutual spacing of the trays (8), therefore, should be correspondingly adapted. Normally this will imply that the trays are correspondingly spaced also in the feeding station. According to the invention the trays are much easier to fill when they are closely juxtaposed, this being achieved by means of a trayconveyor system disposed so as to operate with reduced tray pitch and tray speed in the feeding station.

Description: CONVEYER SYSTEM WITH VARIABLE SPACING BETWEEN THE CARRIER UNITS The present invention relates to a machine for cartonizing articles, of the type comprising an endless feeder conveyor operable to successively move a row of carrier trays past a filling station, in which the trays are tillable, manually or automatically, with articles to be packed, and then past a loading station, in which the articles are automatically pushed from the trays into erected carton members, whereafter the emptied trays are returned by said conveyor to the filling sta¬ tion. The loading station forms part of a carton hand¬ ling line comprising a magazine for prepared flat carton members and a station for erecting these members into a rectangular tubular shape before they are passed to the loading station, while after that station there are further stations for glueing and closing the carton. The transfer of the articles from the trays to the cartons may take place during stillstand or during synchronized co-motion of the trays and the cartons. It is desirable that such a cartonizer be adjust¬ able to the effect that it can handle different sizes of cartons and articles, e.g. such that during one period of time large size units can be handled, followed by a period of handling small size units. Here the said car¬ ton line sets a certain dimensioning limit, viz. with respect to the distance between the consecutive units. The line can be designed to handle carton members of a given maximum width, and it is then possible to use it also for handling members of smaller widths, but what cannot be changed is the pitch of the line. The units themselves may be narrower than those having maximum width, but the distance between their centers or for that sake between their front or rear ends will have to be the same as for units of maximum width. It will be very complicated and expensive to make the carton line adaptable in this respect. Particularly in connection with cartonizers design¬ ed for dynamic transfer of the articles into the carton members, i.e. during co-motion of the trays and the cartons, it is found required to make use of just the same pitch as far as the trays on the feeding conveyor are concerned, such that in the loading station a tray can be lined up with a carton member almost before or immediately after the article on the preceding tray being laterally transferred into its associated carton member. In conventional practice this has given rise to serious problems. It is no problem to provide the feed¬ ing conveyor with article trays having a relevant width for the articles to be packed, as this will only be a question of changing out one set of trays with another set of broader or narrower trays, but for trays narrower than the said maximum width there will occur a certain spacing between the edges of the consecutive trays, and such a spacing is highly inconvenient for a safe opera¬ tion of the feeding station. In that station it is impe¬ rative that the articles can be placed neatly in the trays by a minimum of attention, and particularly in connection with manual filling of the trays it may well happen that the operator places an article in a tray not fully ot not at all centered therein, whereafter it should be relatively easy to correct the positioning of the article by a spimple push on the article. When the trays are of the said maximum width their edges will be closely juxtaposed, i.e. one tray will be followed prac¬ tically immediately by another tray, and the operator can easily secure a correct positioning of the articles on the trays. This becomes more difficult when narrower trays with mutual distance are used, and from the prac¬ tice there are many examples of operators having filled articles down into the open space between two consecu¬ tive trays, this easily giving rise to severe operational disturbances. On this background it is a common practice that the empty spaces between trays narrower that the maximum width are held covered by plate elements located in the top level of the trays, such that the operator cannot lose any article, but easily scrape a misplaced article into the relevant tray. However, these added plate ele¬ ments exhibit some problems of their own, mainly with respect to the costs of their presence and with respect to their driving through the entire conveyor system. According to the present invention the feeding conveyor is arranged so as to allow for a close juxtapo¬ sition of the consecutive trays during the passage of the trays past the filling station, such that the said connecting plate elements between relatively narrow trays can be avoided entirely, while care is still taken that the trays are spaced as required when passing through the loading station; at this place it is unim¬ portant whether or not the trays are interconnected by such plate elements, once the articles have been orderly placed in the trays. The invention calls for three main functions of the feeding conveyor, viz. 1) stowing the relatively narrow trays closely together in the filling station, 2) ex¬ panding the distance between the trays as these are moved through the loading or transferring station for loading the articles into the carton members, and 3) moving the emptied trays as fast as possible back to the filling station, in a number sufficient to ensure a steady presence of a desired number of stowed together trays in that station. It will be understood that in normal continuous operation there will be the same number of trays per time unit passing through any cross section of the con¬ veying path, viz. given by the operational speed of the carton handling line. In the filling station the closely juxtaposed trays will thus exhibit the additional ad¬ vantage of being moved relatively slowly, such that the attendants can place the articles in the trays with still further ease. In a simple embodiment of the invention there is used an ordinary chain conveyor for effecting the above functions 2) and 3) , that is a conveyor equiped to carry the tray units at a pitch or center distance as given by the carton handling line, e.g. typically some 15 inches, while in the filling station means are provided for releasing the tray units from their engagement with the chain and transferring them to.another driving system, in which they are conveyed slowly and closely to each other, and from which they are consecutively delivered back to their engagement with the chain so as to be brought through the loading station with the reduced center distance and speed. Alternatively the trays can maintain their engagement with the chain even when pass¬ ing the filling station, namely if care is taken to reduce the distance between the tray carrying chain portions, leaving the chain slack or bulging out in the spaces therebetween. In a more sophisticated embodiment of the invention a number of different conveyors may be used for forming the closed conveying path of the tray units. In such a system it is possible to control the center distance between the trays by accelerating and decelerating the trays between the stations in which the center distance should be the same, large or small. This will require a good deal of control equipment, but it will largely facilitate the mechanical handling means and provide for an extreme operational flexibility. The conveyor bring- ing the tray units from the rear end of the loading station back to the entrance of the filling station may operate at high speed, i.e. with a very long distance between the trays, and accordingly the total number of tray units in the entire system can be reduced. This is particularly relevant where it is desirable to make use of a high number of trays operatively present in the filling station. Even with the use of the first mentioned chain conveyor it will be possible to arrange for a quick return of the tray units to the filling station, as also in the return run the tray units may be released from the chain and transferred to a separate return conveyor for renewed engagement with the chain when the trays leave the filling station. No matter how the control system is devised, when it is required to switch to another carton and article width it will still be necessary to change out the tray units with other, correspondingly dimensioned tray units, irrespectively of the pitch or center distance in the loading station having to be unchanged. In the mechanically controlled system this will imply a corresponding change out or adjustment of the conveyor means bringing the trays through the filling station, such that also the new trays can be brought closely together in this station, while in the sensor controlled plural conveyor system no such change out will be required, as merely an ajustment of the control settings will be sufficient. In the following the invention is explained in more detail with reference to the drawing, in which:- Fig. 1 is a perspective view of a cartonizer according to the invention Fig. 2 is a schematical side view of a tray system according to the invention, Fig. 3 is a corresponding top view thereof, Fig. 4 is a schematical side view of a modified system. Fig. 5 is a perspective view of a single tray carrier, seen from below. Fig. 6 is an end view thereof, and Fig. 7 is a side or top view of a modified driving element with reference to Fig. 1. The cartonizing apparatus shown in Fig. 1 comprises a table portion A, on which articles to be cartonized in groups can be received, and a row of trays B for receiving the articles in such groups, arranged by an operator of the table. The trays are conveyed into a cartonizer section C, in which the article groups are placed in cartons D, which leave the cartonizer e.g. on a conveyor belt as shown. The system shown in Fig. 1 comprises an endless chain conveyor 2 or rather two such conveyors arranged side by side and having outwardly protruding pins 4 for driving a row of tray carriers 6 along a rail system 7 defining the path of movement of the tray carriers, these each carrying a tray 8. The spacing P between the tray units is determined by requirements set by a coacting carton handling line 10 in the cartonizer C. As shown at the left hand end the conveying of the trays is taken over by a lying conveyor worm 12 provided with a screw groove 14 adpted to receive a downwardly projecting pin 16 on the tray carriers 6. The conveyor chains 2 are guided so as to bypass the screw 12 out of engagement with the tray carriers, and the said guiding rails 7 are arranged such that they will guide the tray carriers directly into engagement with the left hand end of the screw groove and thereafter still stabilize the tray carriers during their following forced movement along the rotating worm body 12. Inversely, when leaving the right hand end of the worm the tray carriers will again be engaged by the pins 4 of the driving chains 2, and they will remain thus engaged and held by the guiding rails 7 until they return to the worm 12 through the lower run of the conveyor. The groove 14 of the screw body 12 has a rather high pitch at both ends thereof, whilst along the middle portion the pitch is considerably smaller. Consequently, as illustrated, the trays 8 will be brought together almost so as to touch each other, i.e. the narrower pitch of the worm body 12 should be adapted according to the width of the trays 8. If the system is rearranged with wider trays it may be required, therefore, to even change out the worm body 12. The area along which the trays are closely juxtaposed will be the said filling area of the infeed conveyor B, where articles can be placed in the trays in a safe and convenient manner, partly because the trays are located directly side by side and partly because they will move relatively slowly trough the filling station. As shown by arrows in Fig. 3, when the trays 8 pass along the carton handling line 10 the articles on the trays will be pushed laterally off the trays and into carton members, but this belongs to the traditional art and will not be further described here. It is illustrated even that the trays 8 are displaced laterally on the tray carriers 6 in order to get close to the carton members, but also this is well known art, and of course the tray carriers should only be designed correspondingly. The trays may well be divided in two or more compartments for plural article packaging. According to a special feature of the invention there may be arranged, between the filling area and the loading area, a station comprising means for automatically pushing a single article into a tray compartment, should an empty compartment be detected. In Fig. 4 is illustrated a slowly moving conveyor 20 extending along the filling area and followed by a controlled acceleration conveyor 22 delivering the trays 8 to a conveyor 24 that moves the trays through the loading station, with the prescribed tray pitch P. A separate return conveyor 26 operates at fast speed for returning the trays with a pronounced widened pitch, such that there will not be many trays running idly in the return run. From the return conveyor 26 the trays are transferred to one or more controlled decelerating conveyors 28, from which the trays are delivered to the filling conveyor 20. It will be appreciated that in a system based on the use of controlled intermediate conveyors between the filling conveyor and the loading conveyor it will be possible to change out the trays with broader or narrower trays as required without changing out the conveyors, as the remaining adaptation will be a question of resetting the control parameters. With reference to Figs. 2 and 3, Fig. 5 illustrates a tray carrier 6 seen from below in a more detailed view. The carrier is constituted by a block member which is provided with lateral grooves 30 for cooperation with the guiding rail system 7, as well as with laterally protruding pin members 32, which can receive between them upstanding dog members 34 on the chains 2, such that each tray carrier can be driven along the guiding rails 7. The chains 2, see also Fig. 6, are guided in fixed C-rails 36, which, at the beginning and the end of the worm 12, are curved so as to bring the dogs 32 out of and into driving engagement with the tray carriers 6 as these, by way of their lower pins 16, engage and disengage the worm groove 14, respectively. The trays 8 are mounted on a support 38, which is laterally displaceable on the carrier 6, guided by a rod 40, whereby the trays can carry out the lateral move- ments discussed in connection with Fig. 3. The worm groove 14 should not necessarily impart a continuous motion to the trays. By way of example it is shown in Fig. 7 that the groove designated 14*' may be arranged so as to extend , by each turn, in a circular manner over a part of the circumference of the worm, whereby the closely juxaposed trays will be moved in a stepwise manner.

Claims: C L I M S ; 1. A machine for cartonizing articles, comprising a filling station, in which articles to be cartonized are placed or grouped in carrier units, a carton erecting station, in which cartons are successively prepared for receiving the articles, a transfer station, in which the articles are successively loaded into the cartons from the carrier units while the cartons are advanced with a predetermined mutual spacing, and a conveyor system operable to move the carrier units from the filling station to and along the loading station, such that in this station the carrier units are advanced successively with a mutual spacing corresponding to that of the cartons, characterized in that the conveyor system is designed in a manner such that the carrier units are advanced with reduced mutual spacing during their passage of the filling station, preferably with their respective article carrying means closely juxtaposed. 2. A machine according to claim 1, in which the conveyor system comprises an endless chain operable to drive the carrier units along the loading station with required mutual spacing between them and further back to the beginning of the filling station, characterized in that the driving means of the conveyor system in the filling station are constituted by a rotating worm having screw shaped driving track or ridge means for cooperation with the carrier units, the said chain bypassing the filling station or passing inoperatively through this station.

Inventors: HOLDENSGAARD PREBEN HOEJER, SPENSER LLOYD MILTON JR, HOLDENSGAARD, PREBEN, HOEJER, SPENSER, LLOYD, MILTON, JR.
Applicants: HOEYER AS O G, O.G. HOEYER A/S
Application year: 1992
Main classification: B65G47
IPC codes: B65G23