The present invention relates to a device for increasing quality control during a seaming process, particularly in seaming processes related to tins for preserving food and the like. Background Art

Seaming is a process that consists in joining two metal sheets by superimposing their flaps and folding them. Seaming is an industrial process that is used on a large scale in several contexts. The food sector, in which the seaming of a container and of the corresponding lid allows to obtain a sealed closure capable of protecting the contents from possible contaminations, is of particular interest.

The need to ensure that the closure of a container is truly of the hermetic type has required the development, over time, of methods that allowed to check automatically or semiautomatically the result achieved by the seaming machine on the processed containers.

Over time, therefore, methods and techniques have been developed which are capable of providing data to a computer, which on the basis of the received information can establish whether the seaming was successful or not.

In particular, machines are known which comprise devices arranged at a seaming cam, which is capable of measuring the force applied for each individual container. If the value is higher or lower than a nominal working range, this means that the container was not closed correctly and must be eliminated or appropriately reprocessed.

Checking the correctness of the closure is entrusted to a computer, which receives, via a suitable electronic circuit board, the signal emitted by such devices. The computer substantially checks the pressure curve received in input and, by comparing it with data that represent a nominal closure, is capable of establishing whether the container was closed correctly or not.

Although existing machines have shown good reliability with reference to quality control in the context of a seaming process, they are however not devoid of drawbacks. In particular, currently available machines are capable of identifying an incorrect seaming but cannot establish, except for a very limited number of defects, which type of defect has affected the closure of a container. Moreover, the number of containers that can be treated per unit time is relatively low and therefore the use of currently available machines in a seaming process can be a limit to production efficiency in automatic machines for filling and sealing containers. Disclosure of the Invention

The aim of the present invention is to overcome the drawbacks noted above with reference to the background art, by providing a device that is capable of improving the performance of existing seaming systems.

Within this aim, an object of the present invention is to provide a device that allows to check, for equal closure heads of a seaming machine, a large number of defects in a very short time.

Another object of the present invention is to provide a device that allows to identify the type of defect detected on a container within a wide range of possible defects.

Still another object of the present invention is to provide a device that can be inserted simply in existing seaming machines in order to improve significantly their performance and results, so as to allow the application of the new device according to the invention also to machines of the previous generation without incurring costs for complete replacement of a plant.

This aim, and these and other objects that will become better apparent hereinafter are achieved by a device for increasing quality control during a seaming process in a seaming machine, comprising means for amplifying a force signal that originates from a carousel of a seaming machine, characterized in that it comprises signal conditioning means, which are adapted to receive in input signals that originate from sensors arranged at said seaming machine, said signal conditioning means being adapted to emit a filtered signal that is adapted to be acquired by processing means, which receive in input also said previously amplified force signal, for comparison between said filtered signal and the force signal and signals correlated to seaming defects of a known type. Brief Description of the Drawings

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the device according to the present invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure l is a schematic view of a seaming apparatus that incorporates the device according to the present invention; Figure 2 is a block diagram of a first circuit board contained in the device according to the present invention;

Figure 3 is a block diagram of a second circuit board contained in the device according to the present invention; and

Figure 4 is a block diagram of a third circuit board contained in the device according to the present invention.

With reference to the figures, the device according to the present invention, generally designated by the reference numeral 1 , comprises means 2 for amplifying a force signal 3 that arrives from a seaming force sensor 4 provided at a carousel 5 through which the objects to be seamed, particularly in this case cans or containers in general 6, are made to pass.

The signal amplifying means 2 are adapted to emit in output an amplified signal, which is input to signal conditioning means 7, which are adapted to emit a force signal that is processed, i.e., filtered so as to reduce as much as possible the noise that it includes, so that such signal, designated by the reference numeral 8, can be acquired by a computer 9 and in particular by an acquisition circuit board 30, which performs a comparison between the signal 8 received in input and signals correlated to known types of seaming defects. Therefore, substantially, the signal 8 in output from the signal conditioning means 7 is acquired by the circuit board 30 and compared with previously stored and mapped signals, each of which corresponds to a repeated seaming defect, so that it is possible to identify the seaming defect that occurred in a given instant, of the seaming operation. The acquisition circuit board 30 is capable of emitting a processed signal 41 to an electronic unit 12, which drives an actuator 13 that allows to reject the container 6 whose seaming has not been found to be optimum.

Conveniently, the signal conditioning means 7 receive in input additional signals besides the seaming force signal 3, amplified by the amplifier means 2.

It should be noted that the force signal 3 is not. processed in the signal conditioning means 7, but in the acquisition circuit board 30, together with the signals in output from the signal conditioning means 7.

In particular, the signal conditioning means 7 receive in input at least one signal 10 that arrives from at least one sensor 1 1 that counts the number of turns of the carousel. The signal 10 is processed, inside the signal conditioning means 7, by a processing circuit board 50, shown in Figure 2.

The signal conditioning means 7 further receive in inpul a signal 14 for synchronization of the container/seaming head, which arrives from the carousel 5 and is processed in a circuit board 16 shown in Figure 3, which is present inside the signal conditioning means 7.

Finally, the signal conditioning means 7 receive in input a signal 17 that indicates a container entering the carousel 5 and a signal 18 that indicates a container exiting from the carousel 5 and arriving from sensor means 19. The signal 17 instead originates from sensor means 40 that detect the inflow of containers to the seaming machine.

The output signal 8 from the signal conditioning means 7 is therefore a signal that is processed by taking into account the signals 10, 14, 17 and 18.

The signals 17 and 18 are processed by a circuit board 20 that is present in the signal conditioning means 7 (Figure 4).

Conveniently, the circuit board 50 shown in Figure 2 has two inputs from proximity sensors, in particular the sensor 1 1 shown in Figure 1 , which generates the signal 10.

Therefore, the circuit board 50 illustrates the processing of at least one signal 10 in input to the circuit board (Figure 2 actually shows the processing of two signals 10 in input to the circuit board 50).

Processing of the signal 10 occurs by means of the passage of the signal through filtering means 21 and then through electrical insulation means 22, in additional filtering means 23 and additional voltage adapter means 24 adapted to bring the voltage from 15 V to 5 V, in order to supply the signal to a DIN connector 25, to which the acquisition circuit board 30 is connected. Conveniently, power supply is provided by way of DC/DC converters

26, which receive in input a direct voltage of 15 V and emit in output a voltage of +/-15 V, always DC.

Figure 3 is a view of the circuit board 16, which receives in input the signal 14 and processes it, by passing it through means 31 for converting from current to voltage, and then through electrical insulation means 32, through noise filtering means 33, and finally in voltage adapter means 34 that are adapted to convert the voltage from 15 V to 5 V.

The circuit board 16 further provides for limitation by way of DC/DC converter means 35, which are entirely similar to the converter means 26 described in relation to Figure 2. Finally, the circuit board 16 has voltage adjustment means 36, which are adapted to adjust the voltage of the voltage adapter means 34.

The reference numeral 37 designates a DIN connector that is similar to the connector 25 of Figure 2. Finally, Figure 4 is a view of the circuit board 20 that receives in input the signals 17 and 18, which undergo a processing that is absolutely similar to the one described with reference to Figure 2. Therefore, the blocks shown in Figure 4 are identified by the same reference numerals already used for Figure 2 and therefore Figure 4 is not described further herein.

The power supply of the circuit boards 50, 16 and 20 is provided, as mentioned, by way of DC/DC converter means, with the result of achieving high reliability, since for an equal operation with respect to the system for generating the +/- 15 V in an oscillating stage and a class A amplifier stage, as occurs in the background art, the working temperature passes from 9O ⁰ C to 25-3O ⁰ C. Moreover, in this manner constant repeatability in the generated voltages is achieved.

Moreover, in the circuit board 16 the presence of the voltage regulator 36 allows to obtain a TTL signal without raising the temperature excessively and without adhering to the signal.

The device according to the invention therefore allows, by means of the seaming force signal 3, processed appropriately within the device, to provide an indication of the seaming quality that is obtained on the several containers subjected to the seaming process. Therefore, the device according to the invention can be implemented on new seaming machines or on existing machines, allowing to establish which type of defect has influenced the closure of a container and therefore its rejection subsequently, so as to be able to intervene to avoid a repetition of the problem. In practice it has been found that the device according to the invention fully achieves the intended aim and objects, since it allows Io increase quality control during a seaming process by processing appropriately and "cleaning" the force signal that is received from the carousel of the seaming machine, together with other signals as explained earlier.

Moreover, the device according to the invention allows to increase the speed of the seaming process and therefore to increase production efficiency.

In practice, by means of the device according to the invention it is possible to utilize to the fullest extent the production speed of seaming machines, while allowing to perform inline quality control, differently from what occurs with known types of quality control devices, which (due to their inherent slowness) force to either reduce the speed of the machine or Io not perform inline quality control. The device thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application no. MI2008A001508, from which this application claims priority, are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each clement identified by way of example by such reference signs.