Patent Description:
Egg trays are available in various types and sizes. A widely used form is an egg tray in which eggs are, or at least should be, packed in a matrix pattern of five rows and six columns. Thirty cups in which the eggs are, or at least should be, placed are formed as cups with a shape that is midway between an inverted truncated pyramid and an inverted dome. The device according to the present invention has been developed in particular for an egg tray of this kind. It ought to be clear, however, that other shapes of egg trays, for example with a matrix of four by five columns, may also be processed with a device according to the invention, as also occurs with known devices. That is possible because the orientation and the distance apart of the eggs in most cases, even with egg trays that are not square but are for example rectangular, coincides with that in the familiar square five by six egg tray.

Between two cups of an egg tray located diagonally next to each other there is always a raised portion in the form of a relatively pointed, truncated pyramid, with sides formed somewhat hollow. By rotating two egg trays stacked, or at least to be stacked, on one another, through <NUM> degrees about a vertical axis, ribs positioned between the cups of the upper of the two egg trays are located above the raised portions of the lower of the two egg trays. Thus, egg trays filled with eggs can be stacked on each other, wherein sufficient space and protection against breakage are provided for fragile eggshells by the two egg trays, at least for the lower of the two egg trays. Stacks of six filled egg trays are usual, but other numbers of egg trays may also be stacked on each other. Often a stack of filled egg trays is protected at the top by an empty egg tray.

It is known to stack the egg trays on each other from the top, but it is also known to form a stack by supplying an egg tray at the bottom every time, a stack so formed, or at least to be formed, always being moved upward a certain amount. The present invention relates to the last-mentioned method.

Filled egg trays to be stacked are usually transported on a supply conveyor, such as an endless belt, to a receiving device positioned under a stacking location of a stacking device. The egg tray is raised from the receiving device by a platform. The platform is provided with a profile with upward-projecting projections, which fit into raised portions of the egg trays. In this way it is possible to ensure that the projections of the egg tray are aligned well relative to the cups of an upper egg tray. Finally the projections of the egg tray engage with cups of a superjacent egg tray and the stack is optionally turned by a defined amount and put back again at the stacking location. This is done as often as required until a desired number of layers is reached (it should be clear that the first (top) egg tray cannot engage on an upper egg tray, but that is not important for the movement). To ensure that two egg trays located one above another are oriented correctly relative to each other, at the stacking location between two successively supplied egg trays the stack is always turned <NUM> degrees, or the platform with the egg tray is turned <NUM> degrees every other time during the raising operation. In this last case, the platform should be turned back again in the movement to the receiving device for proper engagement of the next egg tray.

<CIT> discloses a lifting device according to the preamble of claim <NUM>.

The present invention aims to provide a lifting device wherein a more regular pattern of movements and/or fewer movements are necessary than with the known lifting devices. This is achieved according to the present invention by configuring a lifting device according to claim <NUM>.

The two alternative platforms, a) with upward-projecting projections and b) with holes extending through the platform or blind holes, work per se in the same way. Further, The conical shape of platforms according to alternative a) provides, between the projections, a suitable receiving space for cups of an egg tray to be carried. In platforms according to alternative b), the cups of the egg trays are received with sufficient support in the holes of the platform.

The projections engage on the ribs of an egg tray that are positioned between the cups of the egg tray, but also between the raised portions. However, on account of the patterns of the projections and the holes, the projections and holes are located at the same place when one of the two is turned <NUM> degrees every time about a vertical. Since a platform according to the invention is turned exactly <NUM> degrees between two lifting movements, the action of the two alternatives is identical.

Egg trays are available in various types and sizes. A widely used form is a square egg tray in which eggs are, or at least should be, packed in a matrix pattern of five rows and six columns. The cups in which the eggs are, or at least should be, placed are formed as cups with a shape that is midway between an inverted truncated cone and an inverted dome. The device according to the present invention has been developed in particular for an egg tray of this kind. It should, however, be clear that other shapes of egg trays may also be processed with a device according to the invention, which also occurs with known devices. That is possible because the orientation and the distance apart of the eggs in most cases, even with egg trays that are not square but are for example rectangular, coincides with that in the known square five by six egg tray.

The inventor has discovered that a platform according to the present invention is suitable for engaging on an egg tray from below in two orientations turned <NUM> degrees relative to each other, wherein always half of the projections engage on the underside of the egg tray, or wherein always half of the holes engage on a recess of the egg tray. Thus, in the cycle described above, the platform with an egg tray can be raised, and between the engagement of the egg tray on the upper egg tray and the depositing of the stack of egg trays at the stacking location they are turned <NUM> degrees about a (virtual) vertical rotation axis, wherein the platform does not need to be turned back to the original orientation to engage a subsequently supplied egg tray and raise it. It is alternatively also possible to supply egg trays that are turned <NUM> degrees relative to each other every time and engage on them successively without needing to turn the platform. In both situations, an identical sequence of operations is carried out in each cycle, whereas in the prior art, in successive cycles the platform need not be turned on one occasion, and in the next cycle must be turned to and fro. Thus, the aim of the invention is achieved.

It should be noted that in the case of a platform with upward-extending projections, the projections do not come into contact with a recess of an egg tray that is placed on the platform; it is a number of bridges or ribs, but not all bridges/ribs, between two adjacent cups of an egg tray, that rest on a projection during use. In the two positions of an egg tray turned <NUM> degrees relative to each other, it is thus always other projections that engage on bridges/ribs on the underside of an egg tray. This will be explained in more detail later in the description of the invention, referring to the drawing.

In a preferred embodiment of the present invention, the lifting device is configured for rotating the platform about a vertical axis, in particular through <NUM> degrees. The platform can turn a further <NUM> degrees every time in two successive cycles, or turn to and fro. With this embodiment, a stack of eggs with a supplied lower egg tray can be turned to make it suitable for engaging with a following egg tray from below, as already discussed above.

If the perimeter of the platform has a length and a width that are each smaller than <NUM>, the length and/or width of the platform is less than the length and the width of an egg tray; an edge of an egg tray located on the platform will project beyond the platform, so that the respective edge is free to be able to engage with it from below, for example on a carrying element on which the egg tray or a stack of egg trays is to be deposited by means of the lifting device. The length and/or the width of the platform is preferably less than <NUM>, and more preferably less than <NUM>.

When the platform is provided, on an upper side thereof, with upward-projecting projections, which are configured for being able to engage, in two positions turned <NUM> degrees about a vertical axis, with an underside of an egg tray that is to be carried, the platform does not need to turn back to an original position every time after it has turned <NUM> degrees in order to place an egg platform, turned a quarter turn, under an egg platform located above.

Likewise, when the platform is provided with holes extending through the platform or with blind holes, said holes extending through the platform or blind holes being configured for being able to receive, in two positions turned <NUM> degrees about a vertical axis, cups of an egg tray to be carried, the platform does not need to turn back to an initial position every time after it has turned <NUM> degrees in order to place an egg platform, turned a quarter turn, under an egg platform located above.

If the platform is rectangular, preferably square, it can extend parallel to the edges of an egg tray to be supported. However, other shapes, such as octagonal or round, are also conceivable for the platform and may be functional.

The projections or holes always form a pattern of the five of a dice. The distance apart of the outermost points is equal to that of the center distance of an egg tray to be engaged, to which reference is made in claim <NUM>. In order to make the dimensions independent of an egg tray, which does not itself form part of the claimed invention (but is known as standard), it is preferred that the distance between two adjacent vertexes of said five of the dice is between <NUM> and <NUM>, preferably between <NUM> and <NUM>, and in particular is <NUM>. The center distance is admittedly related to the cups of a specific (five by six) egg tray, but it should be clear that said center distance in this document may be projected onto the platform, i.e. the platform is configured to receive an egg tray with said pattern.

To be able to carry an egg tray stably, it is preferred that a projection, preferably all projections, has/have a flat top surface that is horizontal during use.

To provide on the one hand good engagement of the egg tray and on the other hand to prevent contact of the platform with parts of an egg tray with which the platform should not come into contact, the base of a projection has a diameter from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and more preferably of <NUM>-<NUM>.

It is preferred that the base of the projection has an oval shape. A platform may be used for egg trays with relatively large and relatively small cups. The oval shape at the underside of the projections, which may become round toward the top, may be used for engaging with the relatively wide sides of cups of the relatively small egg trays, and engaging with the relatively narrow side and centering of relatively large egg trays.

For on the one hand providing good engagement of the egg tray and on the other hand preventing contact of the platform with parts of an egg tray with which the platform should not come into contact, the height of a projection is between <NUM> and <NUM>, preferably between <NUM> and <NUM>, and in particular <NUM>.

Lifting device with holes as claimed in one or more of the preceding claims, wherein the holes have a round cross section, or are at least point-symmetric relative to a center of the respective hole. Said shape provides a suitable receiving space for cups of an egg tray to be carried,
So that the cups of the egg trays are received with sufficient support in the holes of the platform, it is preferred that the holes have a diameter of more than <NUM>, more preferably more than <NUM> or <NUM>.

For transmitting a drive to the platform of a lifting and optionally rotating motion, the lifting device preferably comprises an elongated lifting element extending vertically, provided on the underside of the platform.

In use, the invention relates to a lifting device with an egg tray thereon with a matrix pattern of X rows and Y cups, in each of which an egg is placed. The aim and advantages of the first aspect of the present invention.

For application with known shapes of egg trays it is preferred that X is <NUM>, <NUM> or <NUM>.

For application with known shapes of egg trays it is preferred that Y is <NUM>, <NUM>, or <NUM>.

It is preferred that a recess is formed as a depression with substantially a shape of an inverted truncated pyramid, as a depression with substantially a shape of an inverted dome or an intermediate form thereof. Egg trays are generally known and the shape thereof is easily deduced.

It is preferred that in the case of a platform with upward-extending projections, cups of the egg tray, when used on a base surface of the platform located between the projections of the platform, are supported on the platform.

For good support of an egg tray on the platform, it is preferred that the base surface of the platform is flat, and more preferably extends horizontally.

The present invention is usable as the lifting device in a stacking device that is suitable for stacking substantially square egg trays, supplied, or at least to be supplied, by means of a supply conveyor in a supply transport direction under a stacking location, and to be discharged via a discharge conveyor in a discharge transport direction from the stacking location, comprising:.

Known stacking devices of the type described above have, as second carrying elements, four strips defining a rectangle, each hinged about a horizontal axis. Two second carrying elements are fitted to, and rest on horizontal edges of the stacking location. The other two second carrying elements extend at right angles to the discharge transport direction and rest with their ends on the second carrying elements mentioned in the previous sentence. When an egg tray is brought upward by the lifting device, the lifting device pushes the four second carrying elements upward via the egg tray, so that the passage as it were hinges open on four sides. When the egg tray has passed through the passage sufficiently, the hinged strips fall under gravity down to their original position in which they rest on the edges of the stacking location. Then the lifting device moves downward and the lowest egg tray comes to rest on the four strips. A disadvantage of the known device is that the action of the second carrying elements is fault-prone and it is able to support an egg tray better. The second carrying elements arranged at right angles to the discharge transport direction cannot drop downward earlier than the second carrying elements that are carried by and rest on the edges of the stacking location, because otherwise they tilt downward completely. Furthermore, the known second carrying elements can only carry an egg tray over a narrow bottom edge of an egg tray. Egg trays are often made of bulk material, which is very fragile, and becomes very weak if it gets just a bit wet. This has a considerable effect on the carrying capacity of the thin bottom edge of the egg tray. When a stack of egg trays drops downward in the device this produces a lot of rubbish. The device must remain clean, since foodstuffs are being packed by it.

The stacking device can carry a stack of egg trays in a more reliable manner and is not very fault-prone, because the second carrying elements extend at least substantially horizontally and at right angles to the discharge transport direction and are configured to move in a horizontal plane in the transport direction away from each other and toward each other. The motion of the second carrying elements may be motor-controlled and is therefore less fault-prone than in the known device, wherein the motion of the second carrying elements depends on contact with egg trays, and on gravity. In addition, the invention offers the possibility of positioning the second carrying elements better and the design freedom thereof is greater, so that they can be designed better according to their function, A further advantageous effect is that the passage, in the direction at right angles to the discharge transport direction, only needs to be minimally wider than the corresponding dimension of an egg tray, and that in addition it can remain free from parts moving uncontrollably. Another advantageous effect is that the tray only needs to extend minimally above the horizontal plane of the upper transit space, because the carrying elements move a small distance from each other in the same horizontal plane.

If the second carrying elements are elongated, they can carry an egg tray over a relatively large length, substantially the whole length or width thereof, without needing to be bulkier.

It is preferred that in use, cups of the egg tray between the projections rest on the platform, preferably on a plane from which the projections extend upward. The projections themselves thus do not need to engage with their upper sides directly on an egg tray.

It is preferred that the second carrying elements have a longitudinal direction that extends at right angles to the discharge transport direction and a transverse direction, seen from bottom to top, extending slanting toward each other. Moreover, the slant angle preferably corresponds substantially to the slant angle of a corresponding edge of an egg tray to be carried, so that the second carrying elements can engage on the egg tray reliably over a part of or almost the whole height of the corresponding edge of the egg tray.

Sturdy and reliable engagement is further reinforced if the second carrying elements, on a side extending slanting upward, have a profile corresponding to an inner side of a lateral edge of an egg tray. The second carrying elements may comprise a strip extending, in use, transversely to the discharge transport direction, on which there are for example six lips extending slanting upward.

It is preferred that two first carrying elements extend in the supply transport direction. Thus, the respective two first carrying elements may be mounted in the extension of the supply transport device, so that an egg tray can be pushed as it were by the supply conveyor belt with the lateral edges on the respective two first carrying elements.

In a preferred embodiment, the platform has a rectangular, preferably square perimeter. Said shape corresponds to the shape of the most used five by six egg tray and can thus support it well. However, other shapes are also possible, such as a rectangular shape wherein the length differs from the width, or an octagonal or round shape.

In order to allow the platform to pass through the transit space and the passage, and in particular the first and second carrying elements, the perimeter of the platform has a length and a width that are in each case smaller than the length and width, respectively, of a five by six tray [length width tray], wherein the length and/or width are preferably less than <NUM>, more preferably less than <NUM>.

It is preferred that the platform is provided, on an upper side thereof, with upward-projecting projections, which are configured for being able to engage, in two positions turned <NUM> degrees about a vertical axis, with an underside of an egg tray that is to be carried. Thus, an egg tray carried on the platform can be carried, aligned more reliably and possibly better relative to an egg tray at the stacking location, and moved to the stacking location.

It is preferred that the carrying device comprises an elongated lifting element extending vertically, provided on the underside of the platform. Accordingly, by means of a lifting drive known per se, an upward and downward motion can be transmitted to the platform easily, and the weight to be transferred can be limited.

If the carrying device is configured for rotating the platform about a vertical axis, the platform can rotate an egg tray through an angle of <NUM> degrees. This is advantageous, since egg platforms should always be stacked turned <NUM> degrees relative to each other.

In a preferred embodiment, the discharge transport device comprises an endless belt, on which stacked egg trays are placed. If the stack is up to height, i.e. if the desired number of egg trays has been stacked, the rear carrier remains open and the front holder drops down with it. The stacks are led away like this.

It is preferred that the receiving device and/or the stacking location extend at least substantially in a horizontal plane. However, for example when a supply or discharge transport device is oriented slanting relative to the horizontal, the receiving device and/or the stacking location may extend at an angle relative to the horizontal.

The lifting device according to the present invention may be used in a method for stacking egg trays, comprising the steps of:.

wherein the second carrying elements extend at least substantially horizontally and at right angles to the discharge transport direction and, for increasing and reducing the passage, move in a horizontal plane in the transport direction away from each other and toward each other. The invention aims to solve a problem from the prior art corresponding to the first aspect, and has advantages corresponding to the first aspect.

It is then preferred that the egg trays are stacked by means of a stacking device according to the first aspect of the invention.

The present invention will be explained in more detail hereunder, referring to an appended drawing of a preferred embodiment of a device according to the present invention. The drawing and the description do not have any limiting effect on the scope of protection of the present invention, which is only limited by the appended claims. The drawing shows:.

Looking now at the figures, <FIG> show, respectively, a perspective view of an empty stacking device <NUM> for egg trays, in which a device according to the present invention is incorporated, and a perspective view of the stacking device <NUM>, filled with egg trays stacked and to be stacked <NUM>, <NUM>. The stacking device comprises a conveyor belt <NUM> as supply conveyor that forms part of a supply transport device in which, in a manner known per se, eggs are packed in egg trays. In use, egg trays to be stacked <NUM>, in this case filled with five rows and six columns of eggs, are supplied via conveyor belt <NUM>. The egg trays come into a receiving device <NUM>, where they are brought upward by a lifting device <NUM> toward stacked egg trays <NUM> carried by second carrying elements in the form of a front and a rear carrier <NUM>, <NUM>. Egg trays <NUM> stacked to a desired height are deposited by the lifting device <NUM> on the conveyor belt <NUM>, with which the separate egg trays are supplied, and the conveyor belt <NUM> transports the stacked egg trays to a discharge conveyor in the form of a conveyor belt <NUM>, via which the stacked egg trays <NUM> are led away. The discharge conveyor forms part of a discharge transport device that drives the conveyor belt <NUM> and by which the stacked egg trays <NUM> may be fed for example to a palletizing device.

<FIG> show a bottom view of an egg tray <NUM>. This egg tray has a matrix pattern of five rows 21a-21e and six columns 22a-22f with cups <NUM>, in which eggs are placed during use. Note that, because the underside of an egg tray <NUM> is shown here, the eggs are located on the side of the figures turned away from the side in view. The egg tray from <FIG> is shown turned through <NUM> degrees anticlockwise relative to the egg tray from <FIG>. Between the cups <NUM> there are raised portions <NUM> (in these figures, away from the viewer) which in the case of stacked egg trays <NUM>, carry cups <NUM> of egg tray <NUM> stacked thereon. When the egg tray <NUM> with the orientation from <FIG> is stacked on the egg tray <NUM> with the orientation from <FIG>, the cups <NUM> from <FIG> are supported on raised portions <NUM> of the egg tray <NUM> from <FIG>. It is always the cups <NUM> that are located both in row 21b, 21c or 21d and in column 22b, 22c, 22d or 22e, marked in <FIG> with a dark dot, which in use come into contact with platform <NUM>, or <NUM>, which is explained in more detail referring to <FIG> show a top view of platform <NUM> for carrying and for raising and lowering egg trays. The flat base surface <NUM>, and the projections <NUM> with their base <NUM> and flat upper surface <NUM> of the platform <NUM> can be seen in the top view. In <FIG>, contact points in the base surface, which in use come into contact with cups <NUM> of an egg tray, are also marked with black dots. The platform <NUM> is shown in <FIG> in the same orientation with supporting points shown for an egg tray <NUM> that is turned <NUM> degrees. In use, in the stacking device that is described in this document, the egg trays <NUM> are always supplied oriented identically and it is the platform <NUM> that, turned <NUM> degrees every time, engages on the next egg trays <NUM>. The platform <NUM> may of course also be used with stacking devices wherein egg trays <NUM> are supplied turned <NUM> degrees every time.

<FIG> show a top view of platform <NUM> for carrying and for raising and lowering egg trays. The flat base surface <NUM> and the through holes <NUM> in the platform <NUM> can be seen in the top view. In <FIG>, the holes 32a in the base surface, which in use receive cups <NUM> of an egg tray <NUM>, are marked with black lines. In <FIG>, the holes 32b in the base surface, which in use receive cups <NUM> of an egg tray <NUM>, are marked with black lines. The platform <NUM> is shown in <FIG> in the same orientation with supporting points shown for an egg tray <NUM> that is turned <NUM> degrees. In use, in the stacking device that is described in this document, successive egg trays <NUM> are always supplied oriented identically and it is the platform <NUM> that, turned <NUM> degrees every time, engages on the next egg trays <NUM>. The platform <NUM> may of course also be used with stacking devices wherein egg trays <NUM> are supplied turned <NUM> degrees every time. Instead of through holes, blind holes may also be provided in platform <NUM>, which are at least formed so that cups of egg trays can be received therein.

<FIG> shows a perspective bottom view (rotated <NUM> degrees) of the platform <NUM> that supports an egg tray <NUM> (because the arrangement is photographed upside down, the bottom ends of the eggs do not come into contact with the cups. It should be clear, however, that if the arrangement is reversed and the egg tray <NUM> is located on platform <NUM>, the eggs rest in the cups <NUM>). It can be seen in this figure that some cups <NUM> of the egg tray <NUM> rest on the flat base surface <NUM> of the platform <NUM>. On their side, the projections <NUM> of the egg tray <NUM> relative to the platform <NUM> help centering (or vice versa), not only in the state in which the egg tray <NUM> rests completely on the platform <NUM>, but certainly also while bringing the platform <NUM> under the egg tray <NUM>. The upper surfaces of the projections <NUM> do not come into contact with the egg tray <NUM>.

<FIG> shows a perspective bottom view of a platform <NUM> with holes 32a, 32b extending through the platform <NUM> that supports an egg tray <NUM>. It can be seen in this figure that some cups <NUM> of the egg tray <NUM> rest on the edges of holes 32a of the platform <NUM>. The holes 32a center the cups <NUM> of the egg tray <NUM> relative to the platform <NUM>, not only in the state in which the egg tray <NUM> rests completely on the platform <NUM>, but certainly also while bringing the platform <NUM> under the egg tray <NUM>.

Since the principle of the action of a lifting device with a platform <NUM> with holes extending through the platform corresponds to that of a platform <NUM> with upward-projecting projections, the description of the action is not always repeated every time in the embodiment examples.

<FIG> shows a perspective view of a lifting device <NUM>. The lifting device <NUM> has a driven guide wheel <NUM> rotating, or at least rotatable, about a rotation axis <NUM>. The guide wheel <NUM> is of solid configuration in this embodiment example. On the periphery of the guide wheel <NUM> there is a running surface <NUM>, the distance (diameter) of which to the rotation axis of the guide wheel <NUM> displays a jump. In the running surface <NUM> there is a slot <NUM>, which extends (43a) from an abrupt increase in diameter in the peripheral direction centrally in the running surface <NUM> of the guide wheel <NUM> and is then deflected slanting (43b) toward the outside of the running surface <NUM>. In the side surface <NUM> of the guide wheel <NUM> there is an oval groove <NUM>.

A platform <NUM> is carried by a lifting element in the form of a rod <NUM>. Underneath the rod <NUM> there is a cam wheel <NUM> extending at right angles to the rod <NUM>, with cams <NUM>, which project outwards in the plane of the cam wheel <NUM>. Next to the side of the guide wheel <NUM> there is a rocker arm <NUM> with an axis <NUM> that extends at right angles to the plane of the guide wheel <NUM> into the oval groove <NUM>. The rocker arm <NUM> is connected to a transmitting device <NUM> that carries the rod <NUM> with the cam wheel <NUM>.

When guide wheel <NUM> rotates, the rocker arm <NUM> performs a rocking motion, which is converted via transmitting device <NUM> to a vertical up and down motion of the rod <NUM> with the platform <NUM> and the cam wheel <NUM>. When the rod <NUM> and the platform <NUM> are at, or at least near, the highest point, the slot <NUM> of the guide wheel <NUM> engages on one of the cams <NUM> of the cam wheel <NUM>. When the guide wheel <NUM> then turns further, the deflection 43b moves the respective cam <NUM> sideways, so that rod <NUM> with platform <NUM> is turned through <NUM> degrees. Then the guide wheel <NUM> turns further again, so that the rocker arm <NUM> moves the rod <NUM> down again via the transmitting device <NUM>.

<FIG> shows stacked egg trays <NUM> in side view. It can be seen in <FIG> that the egg trays <NUM> stacked on one another are oriented relative to each other turned a quarter turn, i.e. <NUM> degrees every time. Of the upper egg tray <NUM>, only the outermost row 21e of eggs can be seen. In the egg tray <NUM> located thereunder, the outermost column 22a of eggs can be seen. In the egg tray <NUM> located thereunder, the outermost row (21a, not visible in <FIG>) of eggs is obstructed behind the superjacent egg tray <NUM>. In the egg tray <NUM> located thereunder, again an outermost column 22f of eggs is visible. The bottom egg tray is carried by a front carrier <NUM> and rear carrier <NUM>, which are shown in more detail in <FIG>.

<FIG> shows a perspective view of a carrying device <NUM> for carrying egg trays <NUM>. The carrying device <NUM> has a frame <NUM> that supports a carrier <NUM>. During the steps for the stacking of egg trays <NUM>, the frame <NUM> moves to and fro horizontally relative to the stacked egg trays <NUM>, as will be explained in more detail later. It can clearly be seen that the front carrier <NUM> comprises a transverse beam <NUM> and lips <NUM> slanting upward, extending from the transverse beam <NUM>. The lips <NUM> correspond in shape substantially with the raised portions (<NUM>, not shown in <FIG>) on the edge of an egg tray <NUM>. The slanting form of the lips <NUM> corresponds substantially to the angle of projections (<NUM>, not shown in <FIG>) of an egg tray <NUM>. The shape of the lips may be adapted to the egg trays to be carried.

Now looking again at <FIG>, the transverse beam <NUM> and the outer lip <NUM> of front and rear carriers <NUM>, <NUM> are visible. The lips <NUM> engage on inner sides of raised portions <NUM> of the bottom egg tray <NUM>, so that the egg tray <NUM> can be carried reliably by the lips <NUM> over a relatively large area thereof, at least in comparison with a known device wherein the bottom egg tray <NUM> only rests with the underside of the edge of the egg tray <NUM> on a horizontal strip.

<FIG> shows a perspective view of a part of the packaging device <NUM>, in which the platform <NUM> and the carriers <NUM>, <NUM> are visible. The platform <NUM> has a smaller area than a passage that is defined by the carriers <NUM>, <NUM> and by lateral edges <NUM>, <NUM> of the discharge transport device <NUM>. The shape of the lips <NUM> of carriers <NUM>, <NUM> can also be seen in <FIG>.

<FIG> show a side view of a packaging device <NUM> for eggs in successive steps during the stacking of egg trays <NUM>. In particular, it follows the movement of egg tray <NUM>* during the successive steps.

<FIG> shows an initial state of the packaging device <NUM>. The egg tray filled with eggs <NUM>* is brought via conveyor belt (not shown in <FIG>) and a first 7a and second 7b conveyor into the receiving device <NUM>. The egg tray <NUM>*, just like the "next" egg tray <NUM> to be stacked after egg tray <NUM>*, is oriented with the rows <NUM> of eggs in the longitudinal direction or transport direction of the conveyor belt. The platform <NUM> of the lifting device <NUM> is located at a distance directly under the egg tray <NUM>*. Egg tray <NUM>* is located directly under stacked egg trays <NUM>. The orientation of the bottom egg tray <NUM> of the stacked egg trays is turned <NUM> degrees relative to egg platform <NUM>*.

<FIG> shows the next step. Egg tray <NUM>* is gripped by the platform <NUM> on the underside and brought upward, so that the egg tray <NUM>* engages with the upper side on the "previous" egg tray <NUM>, stacked one cycle earlier. The cups <NUM> of the previous egg tray are supported on the raised portions <NUM> of egg tray <NUM>*. The front <NUM> and rear <NUM> carrier under the previous egg tray <NUM> can now be removed, because egg tray <NUM>* and the egg trays stacked above that are carried by the platform <NUM>.

It can be seen in <FIG> that the carriers <NUM>, <NUM> are in fact moved aside, so that egg tray <NUM>* can pass through a passage defined by side walls of the discharge transport device and carriers <NUM>, <NUM>.

It can be seen in <FIG> that the stacked egg trays <NUM>, of which egg tray <NUM>* now forms part, are brought further upward by platform <NUM>, so that the stacked egg trays <NUM> and the platform <NUM> project above the rest of the packaging device <NUM>.

It can be seen in <FIG> that platform <NUM> with stacked egg trays <NUM> thereon is rotated through an angle of <NUM> degrees.

In <FIG>, the platform <NUM> is rotated <NUM> degrees relative to <FIG>. Egg tray <NUM>* is located at the bottom and is now oriented with the rows <NUM> of eggs at right angles to the original orientation and so also to the transport direction. Egg tray <NUM>* now has the same orientation as the egg tray <NUM> which in <FIG> was located at the bottom of the stacked egg trays <NUM>. Thus, the next egg tray <NUM> with the rows in the transport direction can be stacked under egg tray <NUM>*.

In <FIG>, the carriers <NUM>,<NUM> are moved again to their starting position and platform <NUM> moves downward, wherein the carriers <NUM>, <NUM> engage in raised portions <NUM> of egg tray <NUM>*, so that the stacked egg trays <NUM> are again carried reliably.

In <FIG>, the state of the packaging device corresponds to the state that is shown in <FIG>, but the stack of egg trays is now stacked one layer higher, because egg tray <NUM>* now forms the lowest egg tray. The cycle can now be repeated, until the desired number of egg trays <NUM> is stacked. Each cycle of steps 7a-<NUM> is the same, at least with regard to the movements of the lifting device.

When the stack of egg trays has reached a desired height, after the last egg tray forms part of the stacked egg trays <NUM>, the transverse beams <NUM> remain in an open state, so that the lips <NUM> thereof do not engage on the lowest egg tray. The platform <NUM> still rotates of course through <NUM> degrees after the last egg tray is placed under the already stacked egg trays <NUM>. The lifting device <NUM> with the stacked egg trays <NUM> drops downward and deposits the stacked egg trays <NUM> on the conveyor belt, in this case the partial conveyors 7a, 7b which supplied the last (lowest) egg tray. The partial conveyors transport the stacked egg trays <NUM> further in the transport direction under the stacking device thereof, so that a new cycle can begin.

<FIG> show a schematic front view of the lifting device with stacked egg trays <NUM>, supplying an egg tray <NUM>, or discharging stacked egg trays <NUM>, wherein the action of the vertical elements, in this case in the form of cams <NUM>, blocks the passage for an egg tray <NUM>, and keeps it open for stacked egg trays <NUM>. <FIG> shows an egg tray <NUM> supplied by partial conveyors 7a, 7b. Cams <NUM> extend above the partial conveyors 7a, 7b, so that they are located in the conveyor track of the egg tray <NUM>. The cams <NUM> block egg tray <NUM> because they are located in the path of respective cups <NUM> of the egg tray. Whereas the partial conveyors 7a, 7b run continuously, the egg tray <NUM> is stationary and then, as described above, is gripped by platform <NUM> and is brought upward.

After the stacked egg trays <NUM> have reached the desired height, platform <NUM> carries the stacked egg trays <NUM> downward in order to deposit the stacked egg trays <NUM> on the partial conveyors 7a, 7b, see <FIG>. Because during stacking the lowest egg tray is rotated <NUM> degrees every time after it has engaged with the egg tray located above it, the lowest egg tray is, when deposited on the partial conveyors 7a, 7b, in another orientation than during feed of said egg tray. This is clearly visible in <FIG>, wherein the cams <NUM>, which are still in the same place, are positioned just between the cups <NUM> of the lowest egg tray. Because the partial conveyors 7a, 7b are still running, they engage on the stacked egg trays <NUM> and move them in the transport direction further. The raised portions <NUM> in the lowest egg tray form as it were a tunnel, so that the egg tray can pass the cams <NUM> without any problem. It should be made clear that the action is the same if a third partial conveyor (not shown here) also extends between the cams <NUM>.

The present invention is described above only with reference to one embodiment example thereof. It should be made clear that many variants are conceivable within the scope of protection of the invention, which is defined by the claims presented hereunder.

Claim 1:
A lifting device (<NUM>) configured for the carrying and upward displacement of a square egg tray (<NUM>) with a tray length and a tray width and provided with a pattern of a tray matrix pattern of cups (<NUM>) arranged in five rows (21a-e) and six columns (22a-f) for receiving one separate egg in each recess, wherein a mutual center distance of two adjacent cups (<NUM>) in a row (21a-e) is equal to a mutual center distance of two adjacent cups (<NUM>) in a column (22a-f),
the device comprising a platform (<NUM>) extending substantially horizontally with a platform length less than a length and a platform width less than a width of an egg tray (<NUM>) that is carried or at least is to be carried,
characterized in that said platform (<NUM>) either
a) on an upper side thereof, is provided with upward-projecting projections (<NUM>) that are configured for engaging between the cups (<NUM>) of the egg tray on an underside of an egg tray (<NUM>) that is carried or at least is to be carried, wherein a projection (<NUM>) has a shape of a truncated cone or a truncated pyramid, or
b) is provided with holes having a diameter of more than <NUM> extending through the platform (<NUM>) or with blind holes, said holes extending through the platform (<NUM>) or blind holes each being configured for receiving a recess of an egg tray (<NUM>) that is carried or at least is to be carried,
wherein the projections (<NUM>), or the holes, are provided in a platform matrix pattern, wherein projections (<NUM>) or holes are provided according to a portion of said egg tray (<NUM>) to be carried corresponding to the dimensions of said pattern of cups (<NUM>) of said egg tray to be carried, wherein midway between each two adjacent rows (21a-e) of projections (<NUM>) or holes of the tray matrix pattern, an extra row (21a-e) of projections (<NUM>) or holes is provided on, or in the platform (<NUM>), which is staggered relative to the two adjacent rows (21a-e) by half of said center distance.