GB2061216A - Device for temporary storage of material on trays, pallets or the like - Google Patents

Abstract

A device for temporary storage of material on e.g. trays (4) comprises a storage conveyor (8) which is drivable in at least one direction to receive and move the trays, and a lifting device (10, 12) extending along the storage conveyor and arranged to lift the trays (4) from the conveyor (8) and hold them or to return them to the conveyor (8). The lifting device suitably comprises long carriers (10), which lift the under the edges of the trays. The carriers (10) are suitably linked to vertically moving and step-wise synchronously drivable lifting members (21), e.g. cables or chains, which run around individual upper, rotatably mounted supporting wheels (14). The storage conveyor (8) and the lifting device (10, 12, 14) are suitably built into a magazine, which can operate independently or in cooperation with a feed conveyor. <IMAGE>

Description

SPECIFICATION Device for temporary storage of material on trays, pallets or the like The invention relates to a device for temporary storage of material on trays, pallets or the like.

A problem in the manufacture and handling of many different types of goods is the achievement of a buffer storage, on a minimum offloorsurface,to which the goods can be moved with known means of conveyance to be subjected for example to treatment such as maturing and tempering or quite simply being placed out of the way for a certain time to be taken out later using the same means of conveyance. Examples of such handling are the storage of bread awaiting packaging or the stowage of dishes in a large kitchen until the kitchen staff has time to place the dishes in a dishwasher. In these contexts, ordinary conveyor belts and roller conveyors of known type are used to convey the material essentially horizontally or at an incline providing sufficient friction. The material is placed in batches on trays, pallets or the like with specific edge dimensions.

Many solutions to the problem are known, several of which involve the stacking of trays with material vertically in order to reduce the floor space required.

The known devices for insertion and removal of the material are, however, expensive and provide unsatisfactory handling of the material when inserted into and removed from the storage.

The material arranged on trays or pallets is conveyed to the storage device according to the invention by means of a feed-in conveyor, for example a conveyor belt, a roller conveyor or a chain conveyor or a suitable combination of different means for the path of the feed-in conveyor through the room. The feed-in conveyor runs essentially horizontally up to one end of the storage device to permit feeding of one tray or pallet at a time into a storage conveyor in the storage device.

The storage device according to the invention suitably comprises a magazine which essentially encloses the storage space and the storage path and has at least one opening towards the feed-in conveyor as well as service hatches which can be opened. The storage conveyor extends in the longitudinal direction of the magazine and can be made as an endless conveyor belt or chain conveyor with a drive means for driving the conveyor in both directions under the influence of suitable control means, which sense the location and number of the trays on the respective feed-in and storage conveyors. The storage conveyor is suitably intermittently drivable for stepwise feed-in and feed-out of trays to and from the storage conveyor.

Means for feeding trays into and out of the magazine can be, for example, pneumatically operated mechanisms which push a tray from one conveyor to the other. They can also be drivers fixed on the storage conveyor, which engage a tray from the feed conveyor and move it over to the storage conveyor or vice versa. The drivers are suitably spaced farther apart than the dimension of the trays in the longitudinal direction of the storage conveyor, so that the trays on the storage conveyor will have a predetermined close spacing to prevent the edges of adjacent trays from hitting each other.

The storage device according to the invention solves the problem of vertical arrangement of the material with the characteristics disclosed in the main claim.

According to the invention the storage device comprises a stepwise operating lifting device arranged along the storage conveyor and intended to engage the trays placed on the storage conveyor to lift them to a higher level in steps which are dependent on the combined height of the tray and material, until the vertical space between the storage conveyor and the ceiling of the magazine has been filled with horizontal rows of loaded trays. When a magazine has been filled the feeding-in of trays into the magazine stops, and it then serves as a buffer storage, and if needed a second and a third magazine arranged parallel to the first magazine along the feed conveyor, take over subsequent trays from the feed conveyor. The number of magazines along the feed conveyor can be adapted to need and space.

The lifting device in the magazine comprises vertically movable carriers on either side of the storage conveyor. The trays or pallets are arranged on the storage conveyor so that their edges parallel to the conveyor extend outside the conveyor's edges next to which the carriers move.

The carriers suitably have the shape of horizontally directed beams with a flange directed in towards the storage conveyor. When moved upwards, said flange passes by the edge of the storage conveyor and then makes contact with the trays placed on the conveyor and lifts them upwards to the height of one step and-then keeps them at this level.

The carriers are suitably arranged on endless loops in the form of belts, chains or ropes which run around a lower wheel arranged beneath the storage conveyor and an upper wheel vertically thereabove at the upper portion of the magazine. Each carrier is suitably borne by at least two such loops, the lower and upper wheel respectively being arranged on common shafts and driven synchronically by a common drive motor, which can be made to drive the lifting device intermittently upwards or downwards by means of a lift control means, e.g. a cam member arranged on one of the wheels which sees to it that the raising or lowering step is as intended.

When the lifting device has raised a number of batches of loaded trays from the storage conveyor to higher levels in the magazine, the load on the loop drive mechanisms and thus on the lifting motor can be appreciable. In order to reduce the torque generating requirements on the motor as much as possible, the portion of the loops facing away from the storage conveyor can be provided with one or more ballast weights, e.g. in the form of beams of greater weight which are parallel to the carriers.

In order to provide easy and inexpensive installation of storage devices according to the invention for various requirements of large or small buffer storage, a magazine according to the invention is suitably made up of magazine modules of suitable length in the direction of the storage conveyor, each magazine module comprising at least a lifting device with carriers.

The invention will be described in the following with reference to the accompanying drawings, of which Figure 1 shows a plain view of three buffer storages arranged in parallel, for trays of dishes in a restaurant, and Figure 2 shows a vertical section along the line A-A through the storage device in Figure 1.

In Figure 1, a feed-in conveyor 2 is arranged on which trays 4 can be placed for conveyance to a dishwasher 6.

Between the feed-in point and the dishwasher, three storage devices or magazines 1 are arranged perpendicular to the feed-in conveyor to serve as buffer storages for the dishes on the trays.

The trays 4 are-placed lengthwise on the feed-in conveyor 2 in order to be easily transferred sideways on to a storage conveyor 8. The storage conveyor 8, in this case a roller chain conveyor, has a width a which is smailer than the length cofthe trays. The transfer of the trays from the feed-in conveyor 2 to the storage conveyor 8 is accomplished by means of a mechanism (not shown). A sensor detects a tray at the entry to the magazine 1 and starts the feed-in mechanism. When the tray is transferred onto the storage conveyor, the drive motor (not shown) of the storage conveyor starts and drives the storage conveyor one step which exceeds the width of the tray by a certain distance, i.e. so that the trays on the storage conveyor will be spaced a certain distance from each other.

When the tray first fed onto the storage conveyor has reached the opposite end of the storage conveyor, it actuates a member (not shown) for starting the drive motor of the lifting device.

As can be seen from Figure 2, the width a of the storage conveyor 8 is less than the length c of the tray 4. In the lifting device, carriers 10 in the form of L-beams with a flange directed towards the storage conveyor 8 are arranged on both sides af and along the storage conveyor and are attached to endless chains 12 which run over sprockets 14 arranged one on top of the other on either side of the conveyor 8.

The sprockets 14 are fixed on shafts 16, at least one shaft 16 being drivable by means of a lift drive motor (not shown) while the shafts on either side of the conveyor 8 are driven synchronically by means of a mechanism (not shown).

During their vertical movement past the storage conveyor 8, the carrier 10 flanges directed towards the conveyor have a distance b between them which is somewhat larger than the width a of the conveyor 8 but less than the length c of the trays. In order to maintain the predetermined distance b while lifting the batches of trays from the conveyor 8 when filling the magazine 1, guides (not shown) prevent the portions of the chainslloops 12 closest to the con veyor8from curving outwards.

The means (not shown) at the upper portion of the magazine senses when the uppermost step contains trays on the carriers and then stops the driving of the feed-in mechanism and the storage conveyor 8. The magazine is filled as shown in Figure 2, but feedingin can still continue to other magazines which are not completely filled.

Feeding-out of the trays from the filled magazine 1 is done in a reverse manner to that described above.

The carriers with the trays move stepwise downwards and place the trays on the storage conveyor 8 whereupon the storage conveyor starts for stepwise feeding-out of one tray at a time onto the feed conveyor 2 which transports the trays to the vicinity of the dishwasher 6 where the personnel transfers the dishes from the trays to the dishwasher.

Claims (10)

1. Device for temporary storage of material on pallets or the like, e.g. trays especially intended for operation in conjunction with a feed conveyor for trays, characterized in that said device comprises a long storage conveyor which is drivable in at least one direction and is designed to carry the trays, and in that a lifting device is arranged along the storage conveyor to raise the trays from the storage con -veyor and hold them there or return them to the storage conveyor.

2. Device according to Claim 1, characterized in that the lifting device comprises elongate carriers which are parallel to the storage conveyor.

3. Device according to Claim 2, characterized in that on each side of the storage conveyor at least one carrier is linked to at least two synchronically drivable lifting members which are vertically movable on the same side of the storage conveyor.

4. Device according to Claim 3, characterized in that said lifting members are flexible cables or chains which run around individual rotatably mounted upper supporting wheels.

5. Device according to Claim 4, characterized in that the lifting members carry counterweights arranged to reduce the torque on the drive motor of the lifting device caused by the loaded carriers.

6. Device according to any one of Claims 1 - 5, characterized in that the storage conveyor,theiifting device as well as supporting wheels, frames and driving motors are built together in a magazine.

7. Device according to Claim 6, characterized in that sensors arranged in the magazine start and stop the drive motor of the storage conveyor via a control unit for stepwise feeding in and feeding out of trays onto and from the storage conveyor and start and stop the drive motor of the lifting device for stepwise raising and lowering of the carriers.

8. Device according to Claims 6 - 7, characterized in that the magazine is disposed to cooperate with a feed conveyor moving transversely to the storage conveyor.

9. Device according to Claims 6 - 7, characterized in that the magazine is arranged to cooperate with a feed conveyor moving in line with the storage conveyor.

10. Device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.