In prior art, an electronics industry assembly line is known which comprises a number of pallets fit- ted to receive components of a product to be assembled.

Each pallet is provided with an RF-tag carrying stored information about the product to be assembled. Further- more, the assembly line comprises a conveyor con- structed in the shape of an endless loop and fitted to convey the pallets. Moreover, the assembly line com- prises assembly work stations disposed along the main conveyor so that they can receive a pallet from the main conveyor and carry out assembly operations on the product on the pallet within the framework of the work- ing area of the work station. Each assembly work sta- tion is provided with a reading device for reading the contents of the RF-tag before carrying out the assembly operation. Based on the data read from the RF-tag, a data processing device controls the assembly work sta- tion, causing it to perform a number of predetermined assembly operations, such as placing a component on the product and/or on the pallet. This type of flexible modular assembly lines are manufactured e. g. by Prodel Technologies, Carlepont, France. The working principles and details of the assembly line are described e. g. in Prodel patents US 4,519,491, US 4,646,245, US 4,787,496 and US 4,832,171 etc.

In a known assembly line system like this, an example of which is illustrated by the diagram in Fig.

1, the supply of components to the working area of the robot at the work station at the middle of the line is implemented by having a number of components carried on pallets on a storage conveyor A parallel to the main conveyor, and when a given component is needed, the en- tire pallet is moved by means of a transverse transfer gear B into the picking area of the robot.

The problem is that the robot or, in the case of a manual work station, the worker has a specific limited working area, where the pallets take up a large space if they are brought there. The working area of a conventional robot can only accommodate a very limited number of pallets and their feed devices, e. g. only two as in Fig. 1. If there is a larger number of component variants to be assembled by the same robot, it is dif- ficult to supply them on pallets to the working area of the robot. In series production with small series there may be different production lots simultaneously on the assembly line, so such a situation is likely to develop in-process inventories and buffers. Moreover, a change of series cannot be flexibly accomplished without the operator's intervention.

The object of the present invention is to eliminate the drawbacks described above.

The assembly line of the invention is charac- terised by what is presented in claim 1.

According to the invention, the assembly line comprises an automatic storage system disposed in the vicinity of the assembly work station, said automatic storage system comprising a number of storage devices, transfer means disposed between the storage devices and the assembly work station for supplying a predetermined component from a predetermined storage location to the working area of the assembly work station on the basis of data read from the RF-tag.

The invention provides the advantage that the space available in the working area of the assembly work station constitutes no limitation of the number of components that can be assembled in the work station.

The supply of components to the working area does not require a buffer nor is one formed in the working area as the components are fetched from the storage device as necessary. A large amount of different components

can be supplied to and handled by the same work sta- tion.

Furthermore, the work station allows very small production series. A change of series requires no ac- tion on the operator's part.

In an embodiment of the assembly line, the storage device comprises a number of pallets placed over each other, each carrying a number of components.

The transfer means comprise a component conveyor ex- tending from the vicinity of the storage device to the working area of the assembly work station, and a ma- nipulation arm or equivalent provided with a gripping device for gripping a component on a pallet and moving it onto the component conveyor.

In an embodiment of the assembly line, the as- sembly line comprises a carriage fitted to receive and support the component; and a guide for forming a track for the carriage.

In an embodiment of the assembly line, the as- sembly line work station is a manual work station for a worker for the execution of manual assembly operations on a product on a pallet.

In an embodiment of the assembly line, the work station is an assembly robot cell fitted to perform an automatic assembly operation on a product on a pallet.

In an embodiment of the assembly line, the as- sembly line comprises a side conveyor disposed in the area of the assembly work station and branching out from the main conveyor to receive a pallet from the main conveyor and convey it to the working area of the work station for an assembly operation and deliver the pallet back to the main conveyor.

In an embodiment of the assembly line, the as- sembly robot cell comprises a robot provided with a gripping device designed to grip a component on a car- riage in the working area and move it from the carriage to the product being assembled on the pallet.

In an embodiment of the assembly line, the storage device comprises a shelf means provided with supporters on which the pallets are arranged one over the other and an elevating gear for successively moving the supporters in a vertical direction so that the pal- lets are moved upwards, and for moving the supporters for an upper and a lower pallet placed successively over each other with respect to each other when facing the manipulation arm so as to form an interspace be- tween the upper and lower pallet into which the manipu- lation arm together with the gripping device can be in- serted in order to pick up a component from the lower pallet.

In an embodiment of the assembly line, the as- sembly work station has been organised to do assembly work consisting of mounting a component having several variants on a product. The automatic storage system comprises a storage device for each variant, so that the pallets of each different storage device carry the same variant.

In the following, the invention will be de- scribed in detail by the aid of a few examples by re- ferring to the attached drawing, wherein Fig. 1 presents a diagrammatic view of the lay- out of a prior-art assembly line, Fig. 2 presents a diagrammatic lay-out view of an embodiment of the assembly line of the invention.

Fig. 3 presents a lateral view of a diagram- matic section III-III of Fig. 2, and Fig. 4 presents a diagrammatic lay-out view of another embodiment of the assembly line of the inven- tion.

Fig. 2 presents a lay-out view of an assembly line for electronics industry. The assembly line com- prises a number of pallets 1 fitted to receive compo- nents of the product to be assembled, in other words, the-product is assembled on the pallet 1 automatically

or manually. Each pallet is provided with an RF-tag 2 containing stored information about the product being assembled. The information may consist of e. g. a prod- uct code, on the basis of which it is possible to read from a database in a computer a list of components for the product as well as information as to which work station is to be used to assemble certain components.

Furthermore, the line comprises a main conveyor 3 con- structed in the shape of an endless loop for conveying the pallets 1. Disposed side by side along the lower portion of the track of the main conveyor 3 in the fig- ure are different assembly work stations 4; 41,42, 43, 44,45. The assembly line in the example comprises one <BR> <BR> <BR> manual work station 41 hile the other work stations<BR> <BR> <BR> <BR> <BR> <BR> 42,43,44,45 are robot work stations.

At each work station 4 there is a side conveyor 6 branching out from the main conveyor and running in the same direction with the main conveyor. The side conveyor 6 functions as a buffer for the work station.

It receives the pallet 1 from the main conveyor 3 and conveys it to the working area 5 of the assembly the work station for an assembly operation, and after the operation has been completed, the side conveyor deliv- ers the pallet 1 back onto the main conveyor 3. If the buffer of the work station, i. e. the queue of pallets 1 waiting for an operation on the side conveyor 6 is full, then a new pallet 1 destined for the work station will continue along the return track, which is the up- per portion of the track in the figure, back to the be- ginning of the line, which in the figure is the left- hand end of the conveyor, the conveying direction being the anti-clockwise direction.

The assembly work stations 4 carry out various assembly operations on the product placed on the pallet 1. Each assembly work station 4 is provided with a reading device 6 which communicates with the RF-tag 2 and-reads its contents before executing the operation.

Based on the data read in the RF-tag, a work station- specific data processing apparatus controls the assem- bly work station, causing it to perform on the product a number of predetermined assembly operations, such as placing a component on the product and/or on the pal- let. In addition, each work station is provided with means for indicating that the operation has been com- pleted and means for modifying the contents of the RF- tag after completion of the operation.

Assembly work station 4'is an assembly robot cell which performs an automatic assembly operation on the product on the pallet 1. This work station 4'has been designed to carry out assembly of a component hav- ing several variants on the product on the pallet. The assembly robot cell 4'comprises a robot 18 provided with a gripping device 17 for gripping a component on a carriage 14 and moving it from the carriage to the product on the pallet 1. The assembly line comprises an automatic storage system 7 serving assembly work sta- <BR> <BR> <BR> tion 43. In the example in Fig. 2, the automatic stor- age system 7 comprises four storage devices 8. Moreo- ver, it comprises transfer means 9 disposed between the storage devices 8 and the assembly work station 4.

Based on the data read from the RF-tag 2, the data processing apparatus controls the transfer means 9 of the automatic storage system 7, causing them to supply a certain required component from the storage device 8 storing the component in question to the picking area of the robot 18 of the assembly work station 4.

As is also shown in Fig. 2 and 3, the storage device 8 comprises a number of pallets 10 placed one over the other, each carrying a number of components arranged in a matrix formation. The transfer means 9 comprise a component conveyor 11 extending from the vi- cinity of the storage device 8 to the working area 5 of the work station 4. The component conveyor 11 comprises a carriage 14, which is fitted to receive the component

and support it, and a guide 15 forming the track of the carriage. In Fig. 2, the guide extends transversely across the main conveyor 3.

Placed in the immediate vicinity of the storage device 8 is a manipulation arm 13 provided with a grip- ping device 12. The manipulation arm grasps a component on the pallet 10 and takes it to the component conveyor 11. The system has a storage device 8 for each differ- ent component variant so that the pallets 10 of each different storage device 8 carry the same component variant. In the example in Fig. 2 there are four compo- nent variants, but their number is not limited in any way. For the sake of simplicity, the example in Fig. 2 only presents one manipulation arm 13, but in practice it will be advantageous to provide each storage device 8 with a separate manipulation arm 13 serving the par- ticular storage device. Moreover, the example in Fig. 2 comprises two component conveyors 11 parallel to each other.

Referring to Fig. 3, the storage device 8 com- prises a shelf means 19 comprising a number of support- ers 20 on which the pallets 10 are arranged one over the other. Using an elevating gear 21, the supporters can be moved successively in a vertical direction so that the pallets 10 move upward. The pallets 10 can be loaded with components from the lower part of the shelf means 19, from where they are moved upward as soon as the manipulation arm 13 has unloaded them. Unloaded pallets 10 can be removed from the upper part of the shelf means 19. Supporters for a lower pallet 101 and an upper pallet 102 placed successively one over the other, when level with the manipulation arm 13 turning horizontally above the component conveyor, can be moved in relation to each other so that an interspace 22 is formed between the lower and upper pallets, permitting the manipulation arm 13 with the gripping device 12 to

be inserted into said space 22 in order to pick up a component from the lower pallet 101.

Fig. 4 presents another lay-out example in which six storage devices 8 for six different component variants have been arranged in a row parallel to the main conveyor 3. The difference to the assembly line in Fig. 2 is that the transfer means 9 between the storage devices 8 and the main conveyor 3 comprise an auxiliary conveyor 23 parallel to the main conveyor. The auxil- iary conveyor is provided with a transfer table 24 for receiving components from the manipulators 13, which pick them from the storage devices 8. The transfer ta- ble 24 carries the component to a point on the auxil- iary conveyor that lies in the picking area of a trans- fer manipulator 25. The transfer manipulator 25 takes the component and places it onto the carriage 14 of the component conveyor 11, which transports it further to the working area of the robot 18 in the work station, where it is then mounted on the product.

The invention is not restricted to the examples of its embodiments described above, but many variations are possible within the scope of the inventive idea de- fined by the claims.