EP2390193A1

EP2390193A1 - Device for checking the number of aluminium packaging sheets positioned one over the other into a packaging box

Info

Publication number: EP2390193A1
Application number: EP11165968A
Authority: EP
Inventors: Keiichi Nonogaki
Original assignee: Coorayon Ltd
Current assignee: Coorayon Ltd
Priority date: 2010-05-26
Filing date: 2011-05-13
Publication date: 2011-11-30
Anticipated expiration: 2031-05-13
Also published as: IT1400260B1; EP2390193B1; ITMI20100943A1

Abstract

A device for checking the number of aluminium packaging sheets (4) positioned one over the other into a packaging box (3) during the conveyance of said box, comprising:
- a transmitting head (1) that generates an alternating magnetic flux,
- a receiving head (2) arranged opposite said transmitting head,
- conveyors means (5) for conveying said packaging box (3) between said heads (1, 2) and said alternating magnetic flux,
- said receiving head (2) detecting at least an alternating magnetic flux transmitted through said packaging box (3) when said box is conveyed between said heads (1, 2) and between the alternating flux emitted by said transmitting head (1), and generating a corresponding signal,
- and means (6) for determining on the basis of said signal whether or not in said packaging box there is a predetermined number of aluminium packaging sheets,
- said transmitting and receiving heads (1) comprising a coil (8) and a support element (7) wherein said transmitting and receiving heads (1, 2) comprise a non-conductive material case (9) for housing said coil (8) and said support element (7).

Description

The present invention relates to a device for checking the number of aluminium packaging sheets positioned one over the other into a packaging box, according to the precharacterizing portion of the main claim.
This type of devices is described for example in EP1424286 .
The known devices are all provided with means for varying the distance between the alternating magnetic flux transmitting and receiving heads. Each time the height of a packaging to be checked is changed with the prior art means it is necessary to modify also the distance between the transmitting and receiving heads in order to minimize such distance.
It is an object of the present invention to provide a device which enables the accurate detection of a number of aluminium packaging sheets positioned one over the other into a packaging box during the conveyance of said box, without the need of means for modifying the distance between the transmitting and receiving heads.
This and further objects are achieved by a device according to the characterizing portion of claim 1.
The device of the invention and its intended use will be understood from following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 shows in a schematic form the main components of a device according to the invention,
Fig. 2 is a schematic prospective view of a packaging box to be checked by a device according to the invention,
Fig. 3 is a schematic view of a component of the device,
Figs. 4A-C show three orthogonal views of a further embodiment of the component of figure 3,
Fig. 5 shows a perspective view of a core element of the component shown in figures 4A-C
Figs. 6A-C show a perspective view and two lateral views of the component of figures 4A-C attached to different supporting elements.
Fig. 7 shows a perspective view of a further embodiment of a core element of the component shown in figures 4A-C.

As shown in figure 1 a device according to the invention comprises: an inspecting section 10 provided with: a transmitting head 1, that generates an alternating magnetic flux, and a receiving head 2 arranged opposite said transmitting head, and conveyors means 5 for conveying a plurality of packaging boxes 3 between said heads and the alternating flux emitted by said transmitting head.
Each of the packaging boxes 3 houses a plurality of conventional packaging sheets 4 comprising at least an aluminium or other similar metallic layer, positioned one over the other into said packaging box 3 as shown in figure 2. The packaging box 3 is packed with a predetermined number of aluminium packaging sheets 4, into each of which tablets, powders or the like are enclosed. The packaging box and the aluminium packaging sheets may be of any type known to an expert in the field, by way of example the box may be rigid or soft and/or the sheets may comprise just one or a plurality of separate different compartments 4A for containing one or a plurality of products, said sheets 4 comprising one or more metallic layers for example an aluminium layer.
The receiving head 2 detects an alternating magnetic flux emitted by the transmitting head 1 and transmitted through the packaging box 3 when said boxes are conveyed between said heads, and generate a corresponding signal which is imputed to means 6 for determining on the basis of said signal whether or not in said packaging box there is a predetermined number of aluminium packaging sheets.
A detailed description of the above device and their components will not be given as they are well known to an expert in the art.
As shown in figure 3, according to the invention the transmitting and the receiving heads 1, 2 comprise the same components, which are: a bar shaped ferrite core 7, provided with a coil 8 and a case 9 realized in a non-conductive material such as, for example, plastic enclosing these components.
Preferably, the core 7 and the coil 8 are completely enclosed in a plastic material preferably directly moulded over said components, this plastic enclosure forming the case 9 of the heads 1, 2.
Thanks to the non-conductive material of the case 9, the magnetic field generated by the transmitting head according to the invention is bigger than that generated by the heads used in the devices according to the prior art.
Preferably the coil 8 is provided in an end portion 7A of the ferrite core 7, said end portion 7A has preferably a length L2 minor than half the complete length L1 of the bar 7, i.e. L2<=L1 1/2.
The transmitting and receiving heads should be positioned with the end portion 7A of the bar shaped cores 7 provided with the coils 8 facing each other.
The above described particular position of the coil further increases the magnetic field generated and received by the heads 1 and 2 with respect to the conventionally used heads, and increases the sensing range between sensor heads.
On the other hand, the amplitude of the self-oscillation noise and inductance is reduced if the coil is provided on a bar end rather than on its centre.
Preferably, in order to increases the magnetic field generated and received by the heads 1 and 2 with respect to the conventionally used heads, the length L1 of the core 7 is bigger than its diameter D1, and preferably the length L1 is at least two times the diameter D1.
Thanks to the above mentioned technical features of the receiving and transmitting heads 1, 2, the transmitted and received alternating magnetic flux transmitted through the packaging box 3 when said box is conveyed between said heads, is increased and consequently there are also increased the heads sensing range and their sensitivity. Thanks to these improvements of the heads features, they do not need any more to be positioned as close as possible to the boxes to be examined and therefore the checking device does not need any more means for adjusting the position of said heads.
In order to increase the accuracy of the checking device according to the invention preferably the operation frequency of the magnetic fields emitted by the transmitting heads is increased with respect to the prior art devices and is preferably set between 80Khz and 140 KHz.
A further embodiment of an emitting/receiving head is shown in figures 4A-C and 6A-C. The main difference between this embodiment and the previously described one is that the bar shaped core 21 in this new embodiment comprises two cylindrical shaped, preferably ferrite, cores 22A 22B positioned side by side (as shown in detail in figure 5) . Preferably said two cores 22A and 22B have the same shape and dimensions.
Preferably, in order to increases the magnetic field generated and received by the heads 1 and 2 with respect to the conventionally used heads, as for the previous described core 7 also this new core 21 has a length L1 which is bigger than either the depth D1 or width W1 (see figure 5) of each of the two single cores 22A and 22B, and preferably the length L1 is at least two times either the depth D1 or the width W1.
Preferably the coils of the transmitting and receiving bars are different.
Preferably the coil of the transmitting head comprises from 80 to 150 turns and a winding wire having a diameter form 0.1 mm to 0.3mm. Preferably the coil of the transmitting head has an inductance of about from 250 micro Henry to 900 micro Henry.
Preferably the coil of the transmitting head comprises a connection cable which is a one-core shielded cable or two core shielded cable. Preferably the coil of the receiving head comprises from 40 to 70 turns and a winding wire having a diameter from 0.05mm to 0.2mm. Preferably the coil of the receiving head has an inductance of from 80 micro Henry to 250 micro Henry.
Preferably the coil of the receiving head comprises a connection cable which is a twisted two-core shielded cable.
Both receiving and transmitting head use the same, preferably ferrite, core 21 and a same shaped plastic enclosure surrounding said core. Preferably the material used for the core is a very low conductive magnetic material of the type having a resistivity of more than 6.0 Ohm meter and an initial permeability of more than 1,500 and a higher frequency response of initial permeability not changing until more than 150Khz.
In order to increase the magnetic flux transmitted and received between the heads 1 and 2 these heads are preferably connected to a support element 11 realized in a non-conductive material such
In figure 7 there is shown a further embodiment for the bar shaped core of the emitting/receiving heads. This new ferrite core 31 has a parallepipedal shape with preferably rounded vertical sides 32 for not damaging the coil wire. As for the other described cores, preferably, in order to increases the magnetic field generated and received by the heads 1 and 2 with respect to the conventionally used heads, also this new core 21 has a length L1 which is bigger than either the depth D1 or width W1; and preferably the length L1 is at least two times either the depth D1 or the width W1.
Preferred dimension for this core 31 are L1=25 mm, W1=18 mm D1= 8 mm and radius of the rounded vertical sides R=4mm.
Finally it should be stressed that the shape of the body forming the core of the emitting receiving heads 1, 2 could be any three-dimensional geometrical shape permitting to tightly wind a coil around the external side or sides of said body.

Claims

A device for checking the number of aluminium or other metal packaging sheets (4) positioned one over the other into a packaging box (3) during the conveyance of said box, comprising:
- a transmitting head (1) that generates an alternating magnetic flux,

- a receiving head (2) arranged opposite said transmitting head,

- conveyors means (5) for conveying said packaging box (3) between said heads (1, 2) and said alternating magnetic flux,

- said receiving head (2) detecting at least an alternating magnetic flux transmitted through said packaging box (3) when said box is conveyed between said heads (1, 2) and between the alternating flux emitted by said transmitting head (1), said receiving head also generating a signal corresponding to said detected flux,

- and means (6) for determining on the basis of said signal whether or not in said packaging box there is a predetermined number of packaging sheets,

- said transmitting and receiving heads (1) comprising a coil (8) and a support element (7, 21, 31) for said coil characterized in that:

- said transmitting and receiving heads (1, 2) comprise a non-conductive material case (9) for housing at least said coil (8) and said support element (7, 21, 31);

- said support element (7, 21, 31) comprises a body;

- said coil (8) is wound around at least a portion of the most external side or sides of said body;

- said body comprises at least two attached bar-shaped cores (22A, 22B), or one single core.
Device according to claim 1, characterised in that the length (L1) of the body of the support element (7, 21, 31) for the coil (8) is at least twice either its width (W1) or depth (D1).
Device according to claim 1, characterised in that the coil (8) is provided only at an end portion (7A, 21 A, 31 A) of the support element (7, 21, 31).
Device according to claim 5, characterised in that the end portion (7A, 21 A, 31 A) for the coil (8) has a length (L2) minor than half the length (L1) of support element (7), i.e. L2<=L1/2.
Device according to claim 1, characterised in that the transmitting and receiving heads (1, 2) are positioned with their end portions (7A, 21 A, 31 A) of the support element (7, 21, 31) and provided with the coils (8), facing each other.
Device according to claim 1, characterised in that the transmitting head (1) generates a magnetic field with an operation frequency between 80Khz and 140 KHz.
Device according to claim 1 characterised in that the coils of the transmitting and receiving heads (1, 2) are different.
Device according to claim 1 characterised in that the coil of the transmitting head comprises from 80 to 150 turns and/or a winding wire having a diameter comprised between 0.1 and 0.3 mm, and/or that the transmitting head has an inductance comprised between 250 and 900 micro Henry and preferably about 350 micro Henry, and/or that the coil of the transmitting head comprises a connection cable which is a one-core shielded cable or two core shielded cable.
Device according to claim 1 characterised in that the coil of the receiving head comprises from 40 to 70 turns and/or a winding wire having a diameter comprised between 0.05 and 0.2 mm, and/or that the receiving head has an inductance comprised between 80 and 250 micro Henry and preferably about 120 micro Henry, and/or that the coil of the receiving head comprises a connection cable which is a twisted two-core shielded cable.
Device according to claim 1 characterised in that the support element (7, 21, 31) comprises a core, this core being the same for both the receiving and transmitting head (1, 2), and/or that the material used for the core of the support element (7) is of the type having an initial permeability of more than 1,500 preferably about 2300, and/or a higher frequency response of initial permeability staying the same number until more than 150Khz.
Device according to claim 1, characterised in that the core (7, 21, 31) and the coil (8) are completely enclosed in a plastic material, this plastic enclosure forming the case (9) of the heads (1, 2).
Device according to claim 1, characterised in that said support element (7, 21, 31) comprises a body realized in a resistive magnetic material having a resistivity of more than 6.0 Ohm meter preferably about 13 Ohm meter.