A Pallet Stacker

FIELD OF INVENTION

This invention relates to apparatus for stacking pallets. Preferred embodiments of the invention focus on machinery for use in stacking pallets with parcels of granular material.

BACKGROUND

It is known to stack pallets with parcels of grain or similar material. The parcels are built up on each pallet in layers, and the resulting stack is wrapped in plastic film to enhance stability. However a problem with some known modes of doing this is that the stack can be difficult to keep uniform, with sacks protruding beyond the outer edges of the pallet, thereby making the stack unsightly and/or unstable.

OBJECT

It is an object of preferred embodiments of the invention to go at least some way towards addressing the above problem. While this applies to preferred embodiments, the object of the invention per se is simply to provide a useful choice. Therefore, any objects or advantages applicable to preferred embodiments should not be taken as a limitation on claims expressed more broadly.

DEFINITIONS

The term “comprises” or “has”, if and when used in this document in relation to one or more features, should not be seen as excluding the option of there being additional unmentioned features. The same applies to derivative terms such as “comprising” and “having”.

SUMMARY OF THE INVENTION

According to one aspect, the invention is a stacker for use with pallets, comprising:

• a chamber,

• a lift; and

• vibrator means; the stacker formed for stacking of parcels wherein: o the lift is able to receive a pallet and hold it at or adjacent to the top of the chamber; o parcels packed with a fluid material are able to be loaded onto the lift; o the lift is able to be lowered with respect to the chamber while the vibrator means causes walls of the chamber to vibrate substantially without contacting the pallet such that the vibrations transfer to the parcels to move them away from the walls so that they become more closely packed on the pallet and the fluid material in them becomes more densely settled.

Optionally the stacker is adapted to perform such that when the walls vibrate with the pallet inside them there is consistently a minimum 5 mm - 40 mm clearance between the walls and pallet.

Optionally the stacker is adapted to perform such that the clearance is consistently less than 30 mm, less than 25 mm, less than 20 mm, less than 15 mm or less than 10 mm when the walls vibrate.

Optionally the walls of the chamber are anchored to the ground by resilient (eg rubber) mounts to substantially reduce the extent to which vibrations reach the ground.

Optionally the stacker comprises springs which limit the extent to which the walls can vibrate.

Optionally the stacker comprises corner posts which at least assist in supporting the chamber.

Optionally the springs connect the posts to the chamber.

According to another aspect the invention is a method of stacking parcels on a pallet comprising running a stacker machine which has a chamber, a lift (eg a platform) and vibrator means, comprising the steps of: a) locating a pallet on the lift; b) depositing parcels containing a fluid material (eg granules) on the pallet so that at least some of them are in contact with walls of the chamber; c) causing the lift to move (eg to lower) the pallet while the vibrator means causes the walls to vibrate such that at least some of the parcels become more closely (eg more evenly) packed and so that the fluid material in the parcels becomes more densely settled; d) depositing further parcels containing the fluid material on at least some of the parcels previously deposited so that at least some of the further parcels are in contact with the walls of the chamber; e) causing the lift to move (eg to lower) the pallet while the vibrator means causes the chamber’s walls to vibrate to move at least some of the further parcels to become more closely (eg more evenly) packed and such that the fluid material in them becomes more densely settled; and f) repeating steps d) and e) as many times as needed until the pallet has the desired number of parcels arranged in in a stack.

Optionally the stacker machine is a stacker as defined above.

Optionally the fluid material is in the form of one or more of pellets, granules, powder or other particles.

Optionally the fluid material comprises edible grain.

IMAGES

Some preferred embodiments of the invention will now be described by way of example and with reference to the accompanying images, of which-

Figure 1 is an isometric view of a pallet stacker;

Figure 2 is an alternative isometric view of the stacker;

Figure 3 illustrates the stacker when in use with a pallet;

Figure 4 illustrates the stacker with the pallet in the process of being loaded with parcels;

Figure 5 illustrates the stacker with further parcels loaded onto the pallet;

Figure 6 illustrates the stacker when several layers of the parcels have been loaded onto the pallet;

Figure 7 illustrates the stacker when the pallet is at a more advanced stage of stacking; Figure 8 is a schematic side cross-section view of the stacker and the pallet;

Figure 9 is a schematic plan view of the stacker and pallet; and

Figure 10 is a schematic side elevation of the stacker.

DETAILED DESCRIPTION

Referring to Figure 1 , the stacker 1 comprises a chamber 2 having four side walls 3 arranged in a box shape with open ends. The stacker is positioned immediately adjacent to a conveyor belt 4 that delivers parcels 5 (eg sacks) of food grain. The arrangement is such that after each parcel arrives at the end of the conveyor belt next to the stacker, it is picked up in turn and presented to the stacker by a machine hoist 6 which may include a robotic lifter arm.

While the stacker is described in connection with parcels of food grain, it may alternatively be used with fluid materials generally (eg those that can flow), for example other types of granules, pellets, powdered material, or particles generally.

In Figure 1 the hoist 6 has a series of fingers 7 that have begun to engage the parcel 5, but have yet to actually lift it.

Each wall 3 of the stacker is fitted with a motor driven vibrator 8 which causes the respective wall to vibrate, eg shake, when in operation.

Figure 2 illustrates the two sides of the stacker that are not visible in Figure 1 .

Referring to Figure 3, the stacker has a hydraulically driven platform 9 that can move up and down inside the box shaped chamber provided by the walls 3. In the image, a standard timber storage or freight pallet 10 has been placed on the platform 9 by way of a forklift. By way of example only, the pallet may have a width of 1 ,000 mm and a length of

I ,100 mm or 1 ,200 mm. However, the stacker can of course accommodate other pallet sizes.

Referring to Figure 4, the top end of each wall 3 incorporates an outwardly angled panel

I I . Collectively these panels 1 provide the top of the stacker with a funnel 12. In Figure 4 the platform 9 (not visible) has been lowered so that the pallet 10 sits below the top of edge of the funnel. With the pallet in that position the hoist 6 begins to place a layer of the parcels 5 onto the pallet 10. The shape of the funnel encourages the parcels 5 towards a position inside the periphery of the pallet if need be.

Referring to Figure 5, when a layer of the parcels has been placed on the pallet the hoist moves down or descends while, at the same time, the vibrators 8 cause the walls 3 to vibrate rapidly inwards and outwards as indicated by the arrows 12. Figure 5 only shows the arrows 12 for two of the walls, but all four walls vibrate simultaneously in the same way. The rapid vibrations transfer from the walls to the parcels to move them to a more compact levelled layer. This applies not just to the parcels as a whole, but also to the grain inside each parcel. In other words the vibrations transfer into the grain to cause it to become more densely disposed inside its parcel.

Referring to Figure 6, without moving the platform 9 any lower for the moment, the hoist 6 lays another layer 13 of the parcels 5 onto the previously laid row 14.

Referring to Figure 7, the platform 9, and therefore the pallet and parcels, are moved down a level while at the same time the stacker’s walls vibrate again as described above. This serves to more title pack, eg level-out, the second layer 13, while at the same time causing the grain inside its parcels to assume a denser more evenly packed state.

Of course as the stacker vibrates the second layer 13, the first layer 14 below it is vibrated again to further improve the lay of its parcels and the grain in them; that is if they are amenable to this.

The same process is repeated to add layer upon layer of the parcels, with vibrating as each layer of parcels descends; that is until a full stack of the parcels on the pallet has been laid. The platform then moves towards to its lowest position while the walls 3 vibrate. When the platform bottoms out it triggers a switch to indicate that stacking is finished, with the result that vibrations cease. The platform then automatically raises the pallet 10 to a position just above the walls 3 where it is picked up by a forklift and moved. The stack of parcels on the pallet may then be wrapped in plastic film or the like and moved to the desired location for storage or freighting.

Optionally when the platform descends it moves approximately 250 mm each time, although other degrees of movement can be employed to suit the size and type of parcels being stacked. Referring to Figure 8, this schematically illustrates further detail of the stacker 1 . As shown, the walls 3 are arranged around and above a pit 15. The hydraulic mechanism 16 that raises and lowers the platform 9 sits in the pit 15. The arrangement is such that when the platform 9 is in a fully lowered position it holds the bottom of the pallet 10 at ground level. The base of each wall 3 is anchored to and isolated from the ground by way of a rubber mount 17.

Referring to Figures 9 & 10, the stacker incorporates four ground anchored steel support posts 18, one at each corner. Each wall 3 is attached to a corresponding pair of the posts 18 by way of one or more springs 19, preferably at the upper end part of each wall-post combination. The springs are arranged such that each wall is able to vibrate independently of the other walls 3. The springs serve to limit the amount of movement of the walls when they vibrate.

Optimally the vibrations that the stacker produces pass through the contents of the parcels 5 to transfer to and also vibrate the pallet 10. This assists the material inside the parcels become more compact and to achieve greater bulk density, while remaining within the confines of the stacker’s walls 3. However, optimally the walls 3 do not touch the pallet 10 even when they vibrate. There may for example be of 5+ mm clearance between the walls 3 and the pallet at all four sides of the pallet at all times. So, for example, if the pallet 10 is positioned at a 5 mm clearance from the walls 3, then when vibrating the walls move less than 5 mm in the direction of the pallet.

While the parcels may contact the walls 3 when they are first laid down by the hoist, the subsequent vibration of the walls causes the parcels to move away from them to be disposed at, or more within, the periphery of the pallet.

In some embodiments of the invention baffle boards may be secured to one or more of the vibrating walls. Theses may for example be light weight and formed to have a polystyrene core with an aluminum skin. They can be lifted in and out to effectively increase or reduce the space between the vibrating wall(s) and the platform 9, commensurate with the size of the pallet being worked with. They serve to effectively bring the stacker’s vibrating walls closer to one another by filling the gap between them and the pallet with the baffle board. The boards may for example be about 100 mm thick or some other dimension to accommodate the pallet size being worked with. Preferably the stacker 1 and the hoist 6 which moves the parcels onto the platform 9 are robotically controlled and located within a cordoned off fenced area cage for safety.

While the platform 9 is a type of lift, and although this is not preferred, in alternative embodiments it may ascend while the walls vibrate rather than descend.

While some forms of the invention have been described by way of example, it should be appreciated that modifications and improvements can be made without departing from the scope of the following claims.

In terms of disclosure, this document envisages and hereby posits any feature mentioned herein in combination with itself or any other feature or features mentioned herein, even if the combination is not claimed.