FIELD OF THE INVENTION
The present invention relates to a system for packing products, such as various packets or bags into containers, such as trays, cartons or RSC-cases. Such systems are widely used in the food industry, for packing packets of chocolate, dairy products, crisps or other snack products, but may be used in general for packing all sorts of products.
BACKGROUND
Packing systems exists in many different forms; each manufacturer promoting a particular concept. The present applicant has for several years manufactured and to marketed the TP4500 series of packing machines in which the products to be packed are received from a filling station and delivered lying flat on a conveyor belt. The products are fed to a cross feed unit, which basically is a belt dropping the packets onto a table. A cross feed belt which basically transfer the bags 90 degrees sideways. After one cycle, there will be lying a row of products on said table. Then, the row of products are transferred into the receiving container with a pushing mechanism, whereupon the cycle repeats itself until the container is filled.
These prior art packing systems has been shown to work reliable for decades, but unfortunately they have some shortcomings. This is mainly due to the strictly time governed mechanism, e.g. the cycle in the cross feed unit, the push frequency in the pushing mechanism, etc, the system as a whole being fully synchronized. For this reason, each product must be fully identical in size and shape, and must be delivered exactly on time, i.e. supplied with even intervals on the conveyor belt. This restricts the speed obtainable with this system, the system being complicated to realign to other package sizes (there are many components that must be adjusted to preserve the synchronism), the system may only serve one filling station (due to the requirement of strictly even spacing of the packets), the system cannot handle containers with reinforced corners or which are octagonal in form (as such containers require a variable number of packets in each row). As of today, the packing system has become a bottleneck limiting the possible production rate, as filling stations now may deliver products at a higher rate than the packing system may cope with.
Thus, there is a need for a more flexible packing system with a higher operation speed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a packing system that in the last partially satisfies the above need.
This is obtained in a system for vertically packing of products into a container, with a predetermined number of products which are fed singly to the system, as it is defined in the appended claim 1. In particular said system includes:
a shingling unit in which the products are collated with a shingling degree determined by a collated pattern, each product overlapping the previous product to form a product group,
a transfer unit bringing the collected product group into a container filling system, bringing the product group sideways,
a container filling system bringing the product group into the container in a controlled manner,
a container handling unit including means for receiving and holding an upright empty is container, means for tilting the empty container 90 degrees into the container filling system and tilting the full container back into an upright position, and delivering the full container on an outfeed conveyor,
a controller unit adapted to control the operation of said shingling unit, transfer unit, container filling system and container handling unit, wherein the operational speed of each unit is controlled in proportion to the flow of products through each of said units and system.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in detail in reference to the appended drawings, in which:
FIG. 1 shows an overview of the inventive system,
FIG. 2 shows details in a shingling unit and transfer units incorporated in said system,
FIG. 3 shows the container filling system,
FIG. 4 shows a system handling containers,
FIG. 5 is a simplified circuit diagram,
FIG. 6 shows a product merger that may be included in the inventive system.
DETAILED DESCRIPTION
The overview picture in FIG. 1 illustrates an embodiment of the inventive packing system receiving products to be packet in two product streams from respective filling stations (this part of the production setup is not shown in the figure). The products may be filled in various packets, such as pillowed bags, and are fed into the system lying flat (horizontal). The product streams are fed to the upper and lower decks of a product merger 13. Following the product merger there are a shingling unit 14 for collation of a predefined number of products with a various shingling degree (calculated), a transfer unit 15 for sideways transferring of a shingled row of products, a container filling unit 16 for means of filling a predefined number of rows (shingled group of products) into a container row by row, a container handling unit 17 for supplying containers to be filled with products and an outlet conveyor belt 18 on which the filled containers are delivered. The operation of the packing system is controlled by a controller unit 19.
The system operates as follows:
- Products are fed horizontal into the system one by one in one or more rows The inventive system can handle both a single infeed stream and a double infeed stream of products, or in fact a larger number of streams; the number being governed by the capacities of the respective filling stations and packing system.
- The rows are merged into a single product stream in the product merger 13 by putting one product from row 2 in between two products from row 1.
- A product group is formed by shingling a number of products. Each product is transferred 90 degree by a calculated length (shingling length).
- When the correct number of products is obtained, the product group is transferred onto the container filling system.
- The container filling system brings the product group into the container, using a pusher and a compressing plate for a repeatable and controlled filling degree.
- When the predefined number of product groups is obtained the container is tilted 90 degrees and delivered on the outfeed conveyor 18.
- A new container is supplied from the container infeed belt 20, tilted 90 degrees and brought into the container filling system
In the following, each component in the inventive packing system will be described in further detail.
Product Merger
The product merger (FIG. 6) is merging two independent product streams to a single product stream with the speed of two times the individual product streams. The merger is a continuous motion system, regulating the two product streams to create the necessary distance between products, according to product size and speed (in products per minute). The product merger includes two upper deck conveyor belts 61, 62 receiving products from a first filling station, and a lower deck conveyor belt 63 receiving products from a second filling station. The belts are each driven by a asynchronous drive 64, 65, 66. The speed of each drive is controlled by the controller unit 19. At the entrance of each deck there is a detector unit detecting when a product is arriving at the merger from each filling station. The merger will adjust the speed of each belt in such a way that products from one stream are dropped in between products from the other stream, and thus merging the streams into one common stream.
The detectors are used in a feedback loop to establish an even output stream of products. Many packing systems include control stations checking the products delivered from the filling stations. Substandard products, such as the product bag being empty, leaky or overfilled, are removed leaving a hole in the stream. Thus, the streams from each filling station will not be as even as desirable. However, such holes will be detected, whereupon the conveyor speed in the other stream is retarded correspondingly. Said in other words, the merging process is controlled by detecting the actual presence (and position) of the products. In opposition to this, strictly time governed systems could not have handled such uneven streams of products.
Shingling Unit
The shingling unit (FIG. 2), also referred as the patternbuilder, is a unit which transfer each product coming in a row, 90 degrees by a calculated length to obtain the shingling degree. The shingling unit is essentially a conveyor belt 21 arranged 90 degree on the arriving stream of products, the products arriving on the left hand conveyor belt. The shingling unit, together with the transfer unit, is controlled by three asynchronous motors connected to frequency converters and encoders. The speed of the shingling unit is calculated from the product flow entering the machine (calculated in the controller unit 19). By using a high friction conveyor, such as a vacuum conveyor, the number of products per row can fluctuate. Vacuum conveyors include a vacuum chamber underlying the belt; the belt being perforated. This means that the shingling unit may deliver groups of products with variable number of products. For example, if the containers have reinforced corners, which mean that they are octagonal internally, the shingling unit should deliver product groups with a reduced number of products in the first and last row, such as a series of groups with, say 5, 6, 6, 6, 6 and 5 products.
The shingling unit also includes detectors, e.g. an optical detector at the entrance detecting arriving products. The operation of the shingling unit is controlled by the controller unit 19.
Transfer Unit
The transfer unit (FIG. 2) is two conveyor belts 22, 23 transferring the collated row of products into the container filling system (FIG. 3). The conveyor speed is calculated from the pattern and product size, and controlled by the controller unit 19.
Container Filling System
The container filling system shown in FIG. 3 transfers the collated row from the transfer unit and into the container, row by row. The container filling system includes a pushing plate 32 and a transfer plate 34. The pushing plate 32 may be mounted on a linear motor, or another suitable drive mechanism. The transfer plate 34 is operated by a drive mechanism 35 acting on a platform whereupon is mounted said pushing plate 32 and its drive mechanism. This setup allows the pushing plate to operate independently of the transfer plate. By a sequence of pushing the product row in supported on the transfer plate, indexing the container and run the transfer plate out, a precise and reliable filling sequence is obtained. By indexing the container is meant running the container up and down vertically by means of the equipment shown in FIG. 4. This will compact the stack of products lying in the container. The transfer plate 34 is actually a two part unit permitting its width to be easily regulated.
In FIG. 4 is shown a container handling unit including two rails 41, 42 running vertically behind the filling system. On the rails there is mounted a container clamping mechanism holding the container with two vacuum pads 43, 44. The container clamping mechanism also includes a tilting mechanism 45 allowing empty containers received in an upright position to be turned 90 degrees sideway with the opening facing the pushing plate 32. When the container has been filled, the tilting mechanism 45 tilts the container back to the upright position, whereupon the container is lowered to an outlet conveyor belt and released from the vacuum pads 43, 44. A drive 46 moves the container clamping mechanism along the rails while allowing the container clamping mechanism to be indexed, i.e. to be positioned accurately along the rails 43, 44. A person skilled in the art will realize that several of the conveyor belts used in the inventive system may be replaced with other means with similar properties, such as rollers.
Controller Unit
As mentioned above, each component in the system may operate at a variable speed. The variable speed is obtained by use of asynchronous AC motors driven by variable frequency converters in the controller unit 19. The controller unit 19 includes a number of frequency converters, one for each synchronous drive in the system, which are controlled by a main controller. Instead of said AC motors and frequency converters, other solutions could be used to obtain variable speed drives, as is well known to the person skilled in the art. Each unit/component in the system includes at least one sensor in order to determine the flow of products through the unit. The main controller will receive feedback signals from the various sensors and control the speed of the belts to obtain an even flow of products into the containers, i.e. the operational speed of each unit is controlled in proportion to the flow of products through each unit in order to avoid congestion in any unit. It also includes a number of actuators controlling servo drives and pneumatic cylinders in the container filling system, i.e. for holding and turning the containers, run the pushing mechanism and the transfer plate out and in, control the indexing, etc at a variable timing. The controller unit 19 is an essential part of the invention as it allows the system to adopt itself to the actual position and size of the products. The controller unit has a menu driven interface that allows the system to be quickly reprogrammed to handle products or containers of different sizes.
FIG. 5 is a simplified circuit diagram showing the control unit 19 with some of its connected units, here infeed product detector 50, merger 1 product detector 51, merger 2 product detector 52, product merger conveyor 154, product merger conveyor 255, product merger conveyor 356, product merger conveyor 457, shingling conveyor 158, transfer unit conveyor belt 158, transfer unit conveyor belt 259, container filling system pushing plate 510, container filling system transfer plate 511 and container filling system indexing table 512.
The plant is a highly effective reliable packing system for a big various number of products. This means that every product type fed horizontal, which should be collated in a row of various numbers, with or without a shingling degree, and packed vertically in a container, is suitable for the plant.
Patent Application
20110302882
