DESCRIPTION

The present invention relates to a conveying apparatus for eggs which in use takes up eggs from a feed conveyor, conveys them and delivers them in a desired pattern to an egg holder, for example, an egg case or an egg tray for a hatching apparatus.

In packaging eggs, the eggs are typically supplied over a belt conveyor (generally in a conveying direction T lying in a substantially horizontal plane). Due to the oval longitudinal cross section, the eggs are then oriented transversely on the conveyor, but with the pointed end randomly to the left or to the right. The eggs are to be packed with their pointed end facing down. For this reason, at some point between the belt conveyor and the case or tray, the eggs are brought from the width orientation to the longitudinal orientation. Moreover, to be presented to the case or tray in which they are to be packed, the eggs need to be arranged in rows (and columns) corresponding to the package, with a particular mutual center-to-center distance of the longitudinal axes of these rows. It is noted that a row direction is normally parallel to the conveying direction T and a column direction is perpendicular thereto. Accordingly, the direction of a row substantially corresponds to the direction of the paths or tracks followed by the eggs, while the direction of a column coincides with the main direction of a group of eggs that is taken over by the conveying apparatus from an earlier-mentioned supply (or is delivered to a case or tray).

In a known conveying apparatus for eggs, the eggs fall down with their pointed ends facing down into a row of juxtaposed receptacles which are thereupon conveyed vertically in the direction of a package to be presented. During this movement, the receptacles slide towards each other, to bring them from the original mutual distance, determined by the center- to-center distance, in the longitudinal direction to the center-to-center distance of the longitudinal axes of the eggs desired for packaging. The eggs fall into a package in readiness, which is stepwise presented under the receptacles for taking up successive rows of eggs from the conveying apparatus.

A disadvantage of the known conveying apparatus is that the package needs to be presented discontinuously to be able to package the fragile eggs safely. This limits the maximum packaging speed and hence the egg processing capacity. Therefore, the present invention contemplates providing a conveying apparatus for eggs which eliminates this disadvantage, or which at least allows, in a relatively inexpensive manner, augmenting the processing capacity of a packaging apparatus with respect to the known method. This object is achieved according to the present invention by a conveying apparatus for eggs comprising two or more juxtaposed tracks with carriers (i.e., egg supports, egg holders) which in use are carried along by endless chains with a common drive shaft which engages links of the chains, and a common return shaft which engages links of the chains and is driven by at least one chain pulled forward by the drive shaft, wherein the links of each chain between the drive shaft and the return shaft can move relative to each other in the direction of movement of the chain and wherein the chains between the drive shaft and the return shaft are received in a guide element.

As a result of such a configuration, the carriers are aligned both at the beginning and at the end of the path between the drive shaft and the return shaft, under the feeding conveyor and above the cases or trays, respectively. The common drive shaft pushes the links with the first row of carriers exactly in line forwards onto the respective tracks, where eggs from the feed conveyor fall into the carriers. Because the different tracks extend in a converging manner towards the return shaft for reducing the mutual distance between the eggs in a row, the distance of the different tracks (i.e., the distance to be traveled through those tracks) is different. In a traditional conveyor, the carriers from the row hence would not arrive simultaneously at the return shaft and the cases or trays. Through the configuration according to the invention, however, the drive shaft will pull the shortest chain in the return path taut, so that the return shaft, via the links in the return path, is driven by the drive shaft. As a result, also the last links of the path between the drive shaft and the common return shaft are pulled forward simultaneously, so that the last row of eggs arrives simultaneously at the end of the respective path for filling the cases or trays. Any play in the chains, which may be caused by differences in distances to be traveled in the different tracks, is taken up in that the links of a chain in the path from the drive shaft to the return shaft can move relative to each other in the direction of movement of the chain. At least the relatively long chains are thereby, as it were, contracted, since the first links are pushed up the path by the drive shaft, so that at the beginning of the path a buffer is pushed up the path. The last links are pulled off the path and pull the links from the buffer along with them. The middle links are compacted if necessary. Because of the forward movement of the eggs when they fall from the conveying apparatus into the cases or trays and because of the exact alignment, it is possible to present the cases or trays in a continuous forward movement under the falling eggs, so that the egg processing capacity can be enlarged with respect to the known apparatus where the cases or trays need to be presented intermittently under the falling eggs. Thus, the object contemplated by the invention is achieved.

In a preferred embodiment according to the present invention, the links of the chains comprise rings, with two neighboring links in a chain oriented at right angles with respect to each other. Ring-shaped links, at least when the internal diameter of the opening defined by a link is greater than twice the thickness of the material of the link, offer room for a chain to contract in that two links contained in a link can move towards each other within that internal diameter.

It is preferred that horizontally oriented links of the chains in the path from the drive shaft to the return shaft run in a guide. A horizontal link can then on both sides be supported on the bottom side of a slotted guide while the top of the slotted guide prevents the possibility of successive links being pressed over each other. Such a construction can be realized in a simple and inexpensive manner and moreover can be reliably implemented. For a proper guidance of the chains, it is preferred that the links in a return path between the return shaft and the drive shaft are also received in guides.

The present invention is advantageous in particular when tracks in the path from the drive shaft to the return shaft differ from each other in length. In that case, through the present invention, not only is a difference in play between the chains taken up, but also exact mutual tuning of the lengths of the different chains is rendered unnecessary, since an apparatus according to the invention also enables differences in length and deviations of the mutual lengths to be taken up. When the tracks, in any case at least in part, describe a curve, the conveying direction of the eggs on the carriers can be changed. This may be desirable, for example, when a conveyor of packaging material preferably supplies packaging material at an angle with respect to the original conveying direction of the eggs. By mutually aligning the conveying directions of the packaging material and the eggs to be packaged, a high processing capacity can then be realized.

It is preferred that the curve describes a bend of in any case at least substantially 90 degrees. As a result, it is rendered easier for an operator to monitor both the supply of eggs to be packaged and packaging. Alternatively, the curve can describe an S bend. Thus, the eggs can be brought, for example, above the supply of packaging material that is situated next to the supply of the eggs. This prevents upstream trains of the two supplies interfering with each other. When the number of carriers (i.e., egg supports, egg holders) in a relatively long track is greater than the number of carriers in a relatively short track, it is not necessary to generate a relatively large buffer stock for the relatively short track. This would unnecessarily extend the length of the tracks, especially in conveying apparatuses with a right-angled bend. In a preferred embodiment according to the present invention, the mutual distance between two neighboring tracks near the drive shaft is greater than their mutual distance near the return shaft. This is the case, for example, when the rows of eggs need to be straight behind each other to be presented to the package. This is because the center-to-center distance of two neighboring eggs at the drive shaft is determined by the length of the eggs (in the preceding section) and is greater than the mutual center-to- center distance of the packaged eggs.

In an alternative preferred embodiment according to the present invention, the mutual distance between two neighboring tracks near the drive shaft is alternately greater and smaller, respectively, than near the return shaft. Such an orientation is desired when the successive rows of eggs are to be delivered to the package in mutually staggered relation, as may be the case in hatching frames.

As a result, it is possible that the position of the eggs upon supply near the drive shaft by the belt conveyor remains unchanged, while the eggs at the return shaft are presented to the package in a varying position. According to a second aspect, the present invention relates to a method for conveying eggs in carriers in a packaging apparatus. The problems solved by the second aspect correspond to those of the first aspect. To this end, the method comprises the steps of: - presenting juxtaposed carriers, mutually connected by endless conveying elements, in an aligned row under a feed conveyor for eggs;

- pushing up the carriers by a common drive shaft in a buffer zone from the beginning of the path from a common drive device for the endless conveying elements to a common return device for the endless conveying elements;

- pulling an aligned row of carriers by the common return shaft from the buffer zone from the end of the path, the return shaft being driven in a pulling manner by the drive device via at least one of the endless conveying elements, whereby the aligned carriers at the end of the path pull along with them next carriers from the buffer zone, and whereby any play in an endless conveying element is taken up in the part of the conveying element which viewed in the direction of movement extends from the drive device to the return device. It is then preferred that in the method a conveying apparatus according to the first aspect of the present invention is used.

The present invention will hereinafter be elucidated in more detail on the basis of an exemplary embodiment and with reference to the appended drawings, in which: Fig. 1 shows a perspective view of an embodiment of a conveying apparatus according to the present invention;

Fig. 2 shows a perspective view of an alternative embodiment of a conveying apparatus according to the present invention;

Fig. 3 shows an exploded perspective view of guidance for a chain for use in a conveying apparatus according to the present invention;

Fig. 4 shows a schematic side elevation of the orientation of the links of a chain with respect to a common drive shaft and a common return shaft;

Figs. 5a and 5b show alternative embodiments of a packaging apparatus for eggs in which a conveying apparatus according to the present invention is included. Referring to Fig. 1, there is shown a preferred embodiment of a conveyor track 1 according to the present invention. In the conveyor track 1, tracks 2a-2f are included, in which (not shown in Fig. 1) endless chains are trained about a common drive shaft 4 and a common return shaft 5. Egg supports 3 (i.e., the carriers) are advanced over the tracks 2 by the chains.

Fig. 2 shows an alternative embodiment of a conveyor track 21 with four tracks 22a-22d, where (not shown in Fig. 2) endless chains are trained about a common drive shaft 24 and a common return shaft 25.

Fig. 3 shows a partly exploded perspective view of a chain guide 41 with a chain 42 trained over gearwheels 46 and 47, respectively, of a common drive shaft 43 and a common return shaft 44. Provided in a guide block 45 are guide slots 40 in which chain 42 is received. Provided around drive shaft 43 and the return shaft 44 are composite guide elements 48 with guide slots 49. Fig. 4 shows a schematic side elevation of the orientation of links 51 of a chain 52 trained over gearwheels 53, 54 of a common drive shaft 55 and return shaft 56, respectively, in use of the chain 52 in a conveying apparatus according to the present invention.

Fig. 5a shows a packing machine 61 for eggs, in which a conveying apparatus 62 according to the present invention is included between a belt conveyor 63 for supplying eggs and a packing unit 64 for eggs. Shown at 65 and 66 are the upstream train and downstream train, respectively, of the packing machine 61.

Fig. 5b shows an alternative embodiment of a packing machine 71 for eggs, where a conveying apparatus 72 according to the present invention is included between a belt conveyor 73 and a packing unit 74. Shown at 75 and 76 are the upstream train and downstream train, respectively, of the packing machine 71.

Referring now to Fig. 1, there is shown an embodiment of a conveyor track 1 for eggs according to the present invention. The conveyor track 1 exhibits a bend for bridging an angle of approximately 90 degrees and comprises six tracks 2a-2f along which egg supports 3 are pushed forward and pulled forward by chains (not shown in Fig. 1). The supports 3 are configured, in particular, to hold eggs with the pointed ends forwards (i.e., viewed in the conveying direction T). The tracks 2a-2f not only extend in a bend but also are located closer to each other at the end near the return shaft 5 than at the beginning near drive shaft 4. The operation of the conveyor track 1 is briefly explained here, while details will be described later with reference to Fig. 4. At each track 2a-2f, a gearwheel is coupled to common drive shaft 4, which gearwheels engage chains that belong to the respective tracks 2a-2f. Drive shaft 4 successively pushes egg supports 3 (i.e., carriers) via the chains onto the top of the conveyor track 1. At the beginning of the conveyor track 1, in use, eggs are placed, oriented in longitudinal direction, onto egg supports 3. As the egg supports 3 are "pushed" onto the track, the egg supports 3 are well aligned here, so that the rows can be filled fast and accurately (in terms of timing).

At the end of the conveyor track 1, that is, near common return shaft 5, the chains are engaged by gearwheels on the common return shaft 5 and the egg supports 3 in the last row are aligned with respect to each other for delivering the eggs to a packing unit (not shown).

Fig. 2 shows an alternative embodiment of a conveyor track 21 with tracks 22a-22d according to the present invention. In the tracks are egg supports 23 which are pushed forward and pulled forward, respectively, by chains (not shown in Fig. 2) when common drive shaft 24 rotates in the direction of arrow P. The mutual orientation of the tracks 22a-22d allows the number of eggs in a row adjacent the return shaft 25 to be halved with respect to the number of eggs presented by a feed conveyor at the common drive shaft 24. It is noted that given an opposite conveying direction T' (see Fig. 2), and through the mutual orientation of the tracks 22a-22d, it is possible, conversely, for the number of eggs in a row (at a downstream shaft) to be doubled with respect to the number of eggs presented (at an upstream shaft) by a feed conveyor. In that case, the supports 3 may be mounted on the chains the other way around (rotated through 180°, viewed in top plan view) for the purpose of a desired orientation of the eggs (with the pointed ends forwards). Further, in that case, the mutual positions of the supports 3 with respect to each other will be adapted.

Fig. 3 shows an exploded perspective view of a part of the chain drive of a conveyor track according to the present invention. The chain guide 41 for one track of a conveyor track according to the present invention comprises a guide block 45 with guide slots 40 for guiding an endless chain 42 which is trained on gearwheels 46, 47 of common drive shaft 43 and return shaft 44. Near common drive shaft 43 and the common return shaft 44, the chain 42 is guided in composite guide elements 48 which are drawn in mutually spaced relation in Fig. 3 but in use of the chain guide 41 are arranged against each other around a respective shaft 43, 44 and the chain 42. In that condition, throughout its path, chain 42 is confined within the chain guide 41. The importance of the confinement of the chain within a guide will become clear in the discussion of Fig. 4.

In Fig. 4, there is shown schematically and in side elevation an endless chain 52 built up from links 51. Although in Fig. 4 no chain guide is shown, the method that is discussed below can be simply practiced when a chain guide, for example a chain guide as discussed with reference to Fig. 3, is provided. The operation of the apparatus is as follows. Links 51 are trained about gearwheels 53, 54 of a common drive shaft 55 and common return shaft 56, respectively, for driving egg supports in juxtaposed tracks (see, for example, Fig. 1). The gearwheels 53, 54 are rigidly connected with the common drive shaft 55 and the common return shaft 56, respectively. Juxtaposed gearwheels for neighboring tracks are aligned with respect to each other. When common drive shaft 55 rotates, then, in the condition of Fig. 4, link 51a at the top is pushed (on a conveyor track). Also, at the bottom a link 5 Ix is pulled forward by the common drive shaft 55. Because the links 51 are movable with respect to each other in the direction of movement of the chain 52, link 51 will pull the trailing links apart until the chain 52 at the bottom between gearwheel 54 and gearwheel 53 has been pulled taut. This effect in fact continues through to link 5 Iy. When there is some play in chains, common return shaft 56 will be set into motion via the respective gearwheel in that the links "pull" gearwheel 54 via gearwheel 53. At the top, hence where the chain 52 conveys egg supports/carriers for eggs through a respective track, the links of chain 52 are "pushed" on the conveyor track by gearwheel 55 and "pulled" from the conveyor track by return shaft 56. As the links 51 are movable with respect to each other in the direction of movement of the chain, any play at the top of the chain 52 is taken up in that the links slide within each other. This is clearly visualized in Fig. 4 by the links 51a-51i. Link 51a is "pushed" onto the conveyor track by gearwheel 53 and pushes-on link 51c, which in turn pushes-on link 51e, which in turn pushes-on link 51g. Also, in the inner circumference of links 51a, 51c, 51e and 51g, the links 51b, 51d, and 51f can be pushed against each other by trailing portions of the links 51c, 51e, 51g.

Thus, at the beginning of a track, a buffer of links is formed that push each other against each other in the track. On the other side, link 5 Ii pulls link 51h further, which in turn pulls links 51g and 51f further. In this way, links from the earlier-formed buffer are pulled away, with the result that the links are aligned with respect to each other again at common return shaft 56. Thus, a difference in length between juxtaposed chains is taken up by the space within the links 51 at the top of the chain 52, hence in the track. When a chain guide, such as, for example, chain guide 41 from Fig. 3, is used, the chain guide guides not only the chain as a whole but also the individual links, so that the links, as it were, can push on each other. Figs. 5a and 5b, finally, show two packing machines 61 and 71, respectively, in which two different conveying apparatuses 62, 72 according to the present invention are included. In Fig. 5a, the upstream train of a packing unit 64 is situated next to a belt conveyor 63 for eggs. For mutual alignment of packaging units supplied by upstream train 65 and eggs to be packed in them, conveying apparatus 62 exhibits an S-shaped course, while moreover the tracks have a converging course. Thus, eggs initially spaced relatively far apart are presented in mutually close orientation above packing unit 64 for packing the eggs in packaging units. In the downstream train 66, the packaging units are made ready for further processing.

At the packing machine 71 from Fig. 5b, eggs are brought from a belt conveyor 73 in a right angle above packing unit 74. Here, an operator of the packing machine 71 can monitor the supply of eggs via belt conveyor 73, the packing unit 74 as well as the downstream train 76 of the packing machine from a strategic position.

In the appended drawings and the foregoing description, only a few embodiments of a conveying apparatus according to the present invention have been shown and discussed. It will be clear that many variations, whether or not obvious to those skilled in the art, are possible within the scope of protection of the present invention which is determined by the appended claims. For example, the chain can have differently shaped links, or even another drive device may be used, such as, for example, a drive belt, provided that it is suitable for, at least in a track, uncoupling the drive unit and the return unit. Further, egg supports of neighboring tracks may be arranged in mutually staggered relation, so that eggs fall alternately from the respective tracks into a packaging unit, for example for packing eggs in a pattern. Also, it is possible that the carriers of two neighboring tracks are carried along by one chain. Further, the teeth of neighboring gearwheels may be arranged on the return shaft in mutually staggered relation, so that eggs can be packaged in a different pattern than straight columns and rows, for example in that two successive rows or columns are staggered over a half of the center-to-center distance of two neighboring eggs from a row. Further, the tracks may extend, for example, substantially horizontally, or at least partly in other directions. According to a further elaboration, upstream (egg-receiving) parts of the tracks may extend, for example, obliquely upwards (with respect to substantially horizontal track parts), to facilitate egg reception. In that case, an upstream chain shaft of the apparatus (for example, drive shaft 4) may be at a higher position than a position of a downstream chain shaft (for example, return shaft 5) of the apparatus.