JP2008233099A - Metal detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal detection device capable of being calibrated without bringing a metal test piece into contact with an article to be processed while obviating the need of recovery of the metal test piece. <P>SOLUTION: In the outside of a predetermined part of a discharge chute 20 in a combination scale allowing an article to pass through its inside, a metal detector 24 is arranged by catching the discharge chute 20. A test piece 42 is attached to a belt 48 of a nonmagnetic material arranged along the discharge chute 20, and the belt 48 is arranged to make the test piece 42 pass through the metal detector 24 and run by a motor 50. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal detection device, and more particularly, to a metal detection device that allows a metal test piece used for calibration of the metal detection device to pass through a metal detection means.

  The metal detection apparatus described above is installed in the front stage of an article processing apparatus for processing articles supplied one after another, for example, a packaging machine for packaging articles weighed in a predetermined amount, and metal is mixed in these articles. May be used to detect whether or not. An article handling system provided with such a metal detection device is disclosed in Patent Document 1.

  In the article handling system of Patent Document 1, a metal detector is provided outside the exit portion of the discharge chute of a combination weigher for discharging articles to the packaging machine. A fluid operation cylinder is provided above the center of the discharge chute. The rod of this cylinder is formed so as to be able to advance and retract to the outlet portion of the discharge chute where the metal detector is provided. A metal test piece is attached to the tip of the rod. The metal detector is calibrated so that the metal detector detects the metal test piece when the rod is advanced and retracted by supplying and discharging fluid to the cylinder and the metal test piece is moved to the outlet of the discharge chute.

JP 2002-31567 A

  According to the technique of Patent Document 1, since the metal test piece is provided at the tip of the rod, there is an advantage that it is not necessary to collect the metal test piece one by one. However, since the metal test piece and the fluid working cylinder are always installed in the discharge chute through which the article actually passes, there is a possibility of contacting the article to be processed. In particular, if the article to be processed is a food product, it may become unsanitary.

  An object of the present invention is to provide a metal detection device that can calibrate without requiring the metal test piece to come into contact with an article to be processed, without the need to collect the metal test piece.

  The metal detector according to the present invention has a path through which an article passes. This path can be part of the article processing apparatus, for example. Specifically, the weighed article can be a chute that passes through the interior. A metal detection means is disposed outside the predetermined portion of the route with the route interposed therebetween. The metal detection means includes a transmission means and a reception means, and detects the metal when the metal passes within a predetermined interval formed between the two means. A part of the route exists within the predetermined interval. Test piece driving means for passing the metal test piece outside the path and between the metal detection means, that is, within the predetermined interval is provided.

  In a more specific aspect of the test piece driving means, an endless cord band arranged along the path is provided. This endless cord band is made of a non-magnetic material, for example, there is a belt or the like that is exceeded between two pulleys arranged at intervals. The test piece is attached to the endless strap. The endless strap is arranged so that the test piece passes through a predetermined gap formed between the metal detection means, for example, between the transmission means and the reception means of the metal detection means. The endless cord band is caused to travel along the length direction by the driving means. This traveling can always be in the same direction, or the traveling direction can be reversed after the metal test piece passes through the metal detecting means.

  In this configuration, since the endless strap is used, the metal test piece can be returned to the calibration start state by driving the endless strap even after passing the metal test piece between the metal detecting means. it can.

  Further, the article can pass through the path in a free fall. In this case, the drive means causes the endless strap to travel at the free fall speed of the article. The calibration of the metal detection means is desirably performed when the metal test piece moves from above to below in the same manner as the metal actually passes between the metal detection means.

  When configured in this way, the metal test piece moves between the metal detection means at a free fall speed, so that the metal detection means is calibrated when the metal test piece in the free fall state passes through the metal detection means. The metal detecting means can be calibrated in a state closer to the actual passing state of the metal.

  As shown in FIG. 1, the metal detection apparatus of the first reference example of the present invention is installed in an article processing apparatus, for example, a combination scale 2.

  In the combination weigher 2, a plurality of article storage means, for example, weighing hoppers 6 are annularly arranged around the outer periphery of the gantry 4. These weighing hoppers 6 are coupled to a plurality of weighing means, for example, load cells 8 provided in the gantry 4 so as to correspond to the respective weighing hoppers 6. Each load cell 8 generates a weighing signal indicating the weight of an article accommodated in the corresponding weighing hopper 6.

  These measurement signals are supplied to a control unit 10 including a control unit installed in the gantry 4, for example, a CPU. The control unit 10 variously combines the respective weighing signals, and selects a combination in which the total weight is equal to or close to a predetermined target weight from among these combinations. That is, a combination operation is performed. The control unit 10 further controls the weighing hopper 6 selected to discharge the articles from the weighing hoppers 6 constituting the selected combination.

  Article supply means, for example, a supply hopper 12 is arranged on the outer periphery of the gantry 4 so as to be positioned above each weighing hopper 6. The control unit 6 controls the supply hopper 12 corresponding to the weighing hopper 6 that has discharged the article so that the supply hopper 12 that is above the weighing hopper 6 that has discharged the article supplies the article. On the upper surface of the gantry 4, a rectilinear feeder 14 is arranged in an annular shape so as to correspond to each supply hopper 12. The controller 10 controls the corresponding linear feeder 14 so that the corresponding linear feeder 14 supplies articles to the empty supply hopper 12. In addition, a distributed feeder 16 that can supply articles to each linear feeder 14 is disposed in the center of each linear feeder 14. The control unit 10 controls the dispersion feeder 14 so that the articles are supplied to the linear feeder 14 in which the amount of articles is reduced by the supply to the supply hopper 12.

  Articles discharged from the weighing hopper 6 are supplied to a path, for example, the discharge chute 20 via the corresponding collection chute 18. The discharge chute 20 is a linear one having a hollow interior and open at both upper and lower ends, and is arranged such that its length direction is along the vertical direction. Articles that have passed through each collecting chute 20 fall freely inside the discharge chute 20 and are sent to another article processing apparatus, for example, a packaging machine 22, which is located below the lower end of the discharge chute 20. .

  In such a combination, the metal fed into the packaging machine 22 may be mixed with a metal as a foreign object. This mixing may be performed on the article in a stage before being supplied to the combination weigher 2 or on the article while the article is moving through each component of the combination weigher 2. Sometimes. When the article is a food, it is necessary to prevent the sale of the article mixed with metal. Therefore, in the middle of the discharge chute 20, metal detection means, for example, a metal detector 24 for detecting whether or not metal is mixed in the article is provided.

  The metal detector 24 detects a change in the magnetic field generated in the discharge chute 20 and a magnetic field generation unit 24a including a coil that generates a magnetic field in the discharge chute 20 and an oscillation unit that excites the coil. The detection means 24b provided with the detection coil and the signal processing part which processes the signal induced in this detection coil is provided, and these are arrange | positioned on both sides of the discharge chute 20. Since the configuration of the metal detector 24 is known, further description is omitted. When a metal is detected by the metal detector 24, an article including the detected metal packaged by the packaging machine 22 is excluded as a defective product. Alternatively, although not shown, when a sorting means is provided between the lower end of the discharge chute 20 and the packaging machine 22 and a metal is detected by the metal detector 24, an article that is expected to contain the metal is Sorting is performed so as not to be supplied to the packaging machine 22 by the sorting means.

  In order to ensure that the metal is detected by the metal detector 24, it is necessary to calibrate the metal detector 24. For calibration, a calibration device such as a sensitivity calibration device 26 is provided in the vicinity of the metal detector 24.

  The sensitivity calibration device 26 has a cylindrical body 28. The cylindrical body 28 is made of a non-magnetic body (weak magnetic body) that does not take on a magnetic force even when it is disposed in a magnetic field. The cylindrical body 28 is disposed outside the discharge chute 20 along the discharge chute 20 along the length direction thereof. Furthermore, the cylindrical body 28 is also arranged so that a part thereof is located in the detection space of the metal detector 24. As shown in FIG. 2, a metal test piece 30 is accommodated in the cylindrical body 28. The metal test piece 30 is formed in a size that can freely move in the cylindrical body 28 along its length direction. Normally, the metal test piece 30 is located at the lower part of the cylindrical body 28.

  A test piece driving means for applying an impact force for raising the metal test piece 30 along the length direction of the cylindrical body 28, for example, a test piece launcher 32 is provided at the lower portion of the cylindrical body 28. Yes. The launcher 32 has an arm, for example, a plunger 32a, whose tip can enter the inside of the cylindrical body 28 from the lower center of the cylindrical body 28 along the length direction of the cylindrical body 28. The plunger 32a is advanced and retracted by driving means, for example, a solenoid 32b. That is, the solenoid 32b is disposed around the plunger 32a. A return means, for example, an elastic means that can be expanded and contracted, specifically a coil spring 32c is disposed between the lower end of the plunger 32a and the solenoid 32b. When the solenoid 32b is excited, the plunger 32a moves forward while compressing the coil spring 32c, and the tip of the plunger 32a enters the lower end of the cylindrical body 28. At this time, it collides with the metal test piece 30 located at the lower end of the cylindrical body 28, and the metal test piece 30 is driven up toward the upper end of the cylindrical body 28. When the solenoid 32b is demagnetized, the compressed coil spring 32c expands so as to return to its original state, and the tip of the plunger 32a is drawn downward from the cylindrical body 28.

  The metal test piece to which the impact force is applied passes between the metal detectors 24 and moves upward. The current supplied to the solenoid 32 b is appropriately adjusted according to the impact force applied to the metal test piece 30.

  Inside the upper end of the cylindrical body 28, an impact force absorbing means, for example, a sponge-like cushion material 34 is attached. The cushion material 34 is for absorbing the impact force of the metal test piece 30 launched to the upper end of the cylindrical body 28 and allowing the metal test piece 30 to fall freely. That is, when the cushion material 34 is not installed, when the metal test piece 30 is launched with a large impact force, the metal test piece 30 collides with the upper end portion of the cylindrical body 28, which differs from free fall due to the repulsive force at that time. It falls at a speed. In order to prevent this and to allow the metal test piece 30 to fall at a free fall speed, a cushion material 34 is attached. Reference numeral 36 denotes an air vent hole formed in the cushion material 34.

  The state where the article and the metal mixed in the article are falling in the discharge chute 20 is a free fall state. Therefore, the metal detector 24 can be calibrated in a state where the metal test piece 30 is dropped in the same state as that of such articles and the metal mixed in them. When the metal detector 24 is calibrated in a free-fall state, the timing is started when the metal test piece is launched by the test piece launcher 32 (excitation of the solenoid 32b is started). The timer of the metal detector 24 is operated when the timer has timed only for the time required for the metal test piece 30 to contact the upper end of the cylindrical body 28 and to start free fall. Is started by a control means (not shown) to perform calibration. The metal detector 24 can be calibrated when the metal test piece 30 is being launched. In this case, the metal detector 24 may be operated by the control means simultaneously with the launch of the test piece 30 (start of excitation to the solenoid 32b).

  In this calibration apparatus, the metal test piece 30 is launched and passed between the metal detectors 24. However, since the metal test piece 30 falls after the launch, the metal test piece 30 is automatically collected. Can do. Moreover, since the metal test piece is always located in the cylindrical body 28, it can be reliably recovered to the original position. Moreover, since the tubular body 28 is a non-magnetic body, the tubular body 28 provided for collecting the metal test piece 30 does not affect the calibration of the metal detector 24.

  This calibration is performed, for example, before the start of the operation of the combination weigher. However, during the operation of the combination weigher, when the ambient environment of the combination weigher changes, for example, the temperature changes, etc. Calibration can also be performed when there is a change in the sensitivity of the detector 24. In addition, when the recalibration is performed, the article does not come into contact with the calibration device.

  FIG. 3 shows a metal detector of a second reference example of the present invention. In this embodiment, the discharge chute 20a of the combination weigher is arranged not diagonally but obliquely. Since the other configuration of the combination weigher is the same as that of the combination weigher shown in the first embodiment, detailed description thereof is omitted. A sensitivity calibration device 26a is arranged along the discharge chute 20a arranged obliquely. Since the detailed configuration of the sensitivity calibration device 26a is the same as the configuration of the sensitivity calibration device 26 in the first embodiment, detailed description thereof is omitted.

  Thus, even if the discharge chute 20a is inclined, the metal detector 24 can be calibrated as in the first reference example.

  A metal detection apparatus according to an embodiment of the present invention is shown in FIGS. In the metal detection device of this embodiment, the sensitivity calibration device 38 has an endless traveling device such as a belt conveyor 40, and the metal test piece 42 passes between the metal detection devices 24 by the conveyor 40. Since the configuration of the combination weigher including the discharge chute 20 is the same as that of the first reference example, detailed description thereof is omitted.

  Pulleys 44 and 46 are arranged outside the discharge chute 20 so as to be positioned on the same straight line at intervals along the length direction of the discharge chute 20 with an interval in the length direction. A belt 48 is stretched between the pulleys 44 and 46 to form a belt conveyor 40. The belt 48 of the belt conveyor 40 is disposed so as to pass between the metal detectors 24. The belt conveyor 48 travels in one direction shown in FIG. 5, for example, downward by a driving means, for example, a motor 50. The running speed of the belt conveyor 48 can be changed, for example, by changing the magnitude of the voltage applied to the motor 50 by a control means not shown.

  The belt 48 is made of a non-magnetic material, for example, a synthetic resin, and a metal test piece 42 is attached in the middle thereof. It is also possible to embed a metal test piece 42 in the belt 48. In FIGS. 4 and 5, reference numeral 52 denotes a frame on which the motor 50, the pulley 44, and the like are arranged, and the discharge chute and the belt conveyor 40 pass through the holes formed in the frame. .

  For example, a voltage is applied to the motor 50 from the origin position where the metal test piece 42 is located near the upper end of the belt conveyor 40, that is, in the vicinity of the pulley 44, and the belt 48 is caused to travel downward. To run. During this traveling, the voltage applied to the motor 50 is gradually increased proportionally to cause the metallic test piece 42 to travel downward at the same speed as that when the metallic test piece 42 is freely falling. . The metal detector 24 is calibrated by a metal test piece 42 that travels at a free fall speed. 2 formed at intervals in the belt 48 so as to detect the presence of the metal test piece 42 at the origin position and the arrival of the lower end of the belt conveyor 40, that is, the half-circumferential position in the vicinity of the pulley 46. An identifier sensor 52 in which one identifier is provided in the vicinity of the motor 50 is provided. A control means (not shown) starts driving the motor 50 in a state where the identifier sensor 52 detects the origin position. In a state where the identifier sensor 52 has detected the half-circumferential position, the control means stops the running of the belt 48 at the free fall speed, and then causes the motor 50 to run the belt 48 at the constant speed to the origin position. To control. The return to the origin position can be performed by traveling the belt 48 in the same direction as traveling at the free fall speed, or can be performed by traveling the belt in the opposite direction. is there. However, when the belt 48 is traveled in the same direction as travel at the free fall speed, it is not necessary to change the polarity of the voltage applied to the motor 50, and thus control is facilitated.

  This calibration is basically performed before the operation of the combination weigher. However, if there is a possibility that the sensitivity of the metal detector 24 may vary during the operation of the combination weigher, the calibration can be performed. Even in this case, the calibration device does not come into contact with the article, which is hygienic.

  In the above embodiment, the metal detector is provided in the discharge chute 20 of the combination weigher, but it is not necessary to be limited to the combination weigher, and it is necessary to prevent the article from passing through and mixing the metal into the article. If there is a certain path, metal detectors can be installed in various paths. In the above-described embodiment, the discharge chute 20 is arranged in the vertical direction, but the discharge chute 20a arranged obliquely as in the second reference example is also the same as the above-described embodiment. Similarly, a metal test piece can be run by a belt conveyor to calibrate the metal detector.

It is a schematic block diagram of the combination scale provided with the metal detection apparatus of the 1st reference example of this invention. FIG. 2 is a front view of the metal detection device of FIG. It is a partially broken front view of the metal detection apparatus of the 2nd reference example of this invention. It is a top view of the metal detection apparatus of one Embodiment of this invention. It is a front view of the metal detection apparatus of FIG.

Explanation of symbols

2 Combination scale 20 Discharge chute (path)
24 Metal detector (metal detection means)
42 Metal test piece 40 Belt conveyor 48 Belt (endless tie)
50 Motor (drive means)

Claims (2)

A path through which the article passes;
A metal detecting means disposed outside the predetermined portion of the path with the path interposed therebetween;
A test piece driving means that is outside the path and allows the metal test piece to pass between the metal detection means,
The test piece driving means has a non-magnetic endless strap disposed along the path, and the test piece is attached to the endless strap. A metal detection device that is arranged to pass between detection means, and the endless strap is made to travel by a drive means along its length direction.   The metal detection apparatus according to claim 1, wherein the driving unit causes the article to pass by free fall and travel the endless strap at a free fall speed of the article in the path.

Images