CN106443797B - Metal detector - Google Patents

Abstract

The invention provides a metal detector. The metal detector eliminates the influence of surrounding electromagnetic waves without causing malfunction. The metal detector includes: a search coil (22) in which a coil for metal detection is housed inside a rectangular parallelepiped body, the surface of the body being a detection surface (22 a); and shield members (36, 34) disposed so as to surround the periphery of the search coil.

Description

Metal detector

Technical Field

The present invention relates to a metal detector capable of detecting whether a metal piece is mixed in or attached to an object to be inspected.

Background

As a conventionally known metal detector, for example, a metal detector having a structure shown in patent document 1 orpatent document 2 is known.

The metal detectors disclosed inpatent documents 1 and 2 pass a subject through a probe coil formed in an annular shape. Thus, when the metal piece is mixed or attached to the object, the magnetic field in the search coil changes. Therefore, by detecting the disturbance of the magnetic field, it is possible to detect that the metal piece is mixed in or attached to the subject.

Further, even if the annular search coil is not provided as described above, it is possible to detect that the metal piece is mixed in or attached to the subject by passing the subject over the upper surface of the coil as disclosed in patent document 3.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 9-80162

Patent document 2: japanese patent laid-open publication No. 2005-292095

Patent document 3: japanese laid-open patent publication No. 2009-92599

Disclosure of Invention

Problems to be solved by the invention

In a metal detector using the above-described search coil, a problem of malfunction may occur.

The cause of the malfunction can be estimated as the influence of various electromagnetic waves, but there are a large number of devices as electromagnetic wave generation sources, such as inverters of power supply devices and mobile phones, and the emission of electromagnetic waves cannot be blocked for all of these electromagnetic wave generation sources.

In view of the above, it is an object of the present invention to provide a metal detector that reduces the influence of surrounding electromagnetic waves without causing malfunction.

Means for solving the problems

The metal detector of the present invention is characterized by comprising: a search coil in which a coil for metal detection is housed inside a rectangular parallelepiped main body, a surface of the main body being a detection surface; and a shield member disposed so as to surround the periphery of the search coil.

With this configuration, since the shielding member shields the surrounding electromagnetic waves, malfunction due to the influence of the electromagnetic waves can be prevented.

The shield member may include two conductor frames to which both ends of the search coil in the longitudinal direction are fixed in an insulated manner at substantially a central portion thereof, and a conductor coupling member that couples the vicinities of both ends of each of the conductor frames to each other, the search coil may be unitized with the shield member, and the search coil unitized with the shield member may be attached to two body frames extending in the transfer direction of the object.

With this configuration, since the search coil unit can be provided integrally with the shield member for eliminating the influence of the surrounding electromagnetic waves, the electromagnetic waves from the surrounding can be blocked regardless of the configuration of the other portion such as the roller.

A search coil unitized with the shield member may be attached to each of the body frames via a vibration-proof rubber as a non-conductor.

With this configuration, the search coil can be separated from the interference noise current flowing to each of the body frames. Further, since vibration from the surroundings is not transmitted to the search coil by the vibration-proof rubber, malfunction due to vibration can also be prevented.

The conductor connecting members may be cylindrical members, and the surfaces thereof may be arranged on the same plane as the detection surface of the search coil.

With this configuration, the transfer of the object can be guided by the conductor connecting member, and therefore the object can be smoothly transferred.

The detection coil may be fixed to two body frames extending in a transfer direction of the object, and the shielding member may include each of the body frames and two conductors connecting the body frames at positions on an upstream side and a downstream side of the detection coil in the transfer direction of the object.

With this configuration, even when the search coil is not unitized with the shield member, malfunction due to the influence of electromagnetic waves from the surroundings can be prevented from occurring.

The two conductors may be rollers having metal shafts and assisting in transferring the object to be detected.

With this configuration, since the conductor serving as the shielding member also serves as the roller, the electromagnetic wave can be shielded without increasing the number of components.

The shield member may include two conductors having flat plate-like portions attached to an upstream side surface and a downstream side surface of the probe coil in the transfer direction of the object to be detected via insulating plates, and two conductor tubes or conductor plates; the two conductor pipes or the conductor plates connect end portions of the conductors to each other.

In the case where a bearing is provided between each of the body frames and the two conductors or between members that connect the body frames to each other, the bearing may be insulated from the body frames.

The effect produced by this structure is as follows. That is, an oil film of grease adheres to the bearing, and an electrically unstable state occurs in which current flows or does not flow due to rotation of the bearing. When a high-frequency current caused by a leakage magnetic field of the search coil flows into the electrically unstable bearing, the magnetic field of the search coil is secondarily disturbed, which causes a malfunction. However, by insulating the bearing from the body frame, it is possible to prevent the generation of an electrically unstable electric network without causing malfunction.

The shield member may have a cover portion that is disposed at a position facing at least the detection surface of the search coil with a predetermined gap therebetween and covers the search coil.

With this configuration, although a leakage magnetic field is generated around the search coil based on the high-frequency magnetic field on the detection surface of the search coil, the influence of the surrounding electromagnetic wave is reduced, whereby the variation in the leakage magnetic field can be reduced, and stable detection can be performed.

The metal detector may have a plurality of support portions for fixing the cover portion to the search coil.

The metal detector may include two conductor frames to which both ends of the search coil in the longitudinal direction are fixed in an insulated manner at substantially a central portion thereof, and a conductor coupling member that couples vicinities of both ends of each of the conductor frames to each other, wherein the search coil to which the cover portion is attached is unitized by the conductor frames and the conductor coupling member, and the unitized search coil is attached to two body frames extending in a transfer direction of the object to be detected.

With this configuration, the search coil is doubly shielded, and the double shielding can reduce the malfunction of the search coil.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide a metal detector that does not cause malfunction due to external electromagnetic noise.

Drawings

Fig. 1 is a side view of embodiment 1 of the metal detector.

Fig. 2 is a top view of the search coil unit.

Fig. 3 is a side view of the search coil unit.

Fig. 4 is a front view of the search coil unit.

Fig. 5 is a side view ofembodiment 2 of the metal detector.

Fig. 6 is a side view ofembodiment 2 of the metal detector.

Fig. 7 is a plan view illustrating a mounting structure of the search coil unit and the body frame.

Fig. 8 is a side view of the embodiment of fig. 7.

Fig. 9 is a side view showing another mode of the embodiment of fig. 7.

Fig. 10 is an explanatory diagram showing an insulation structure of the bearing.

Fig. 11 is an explanatory view showing another insulation structure of the bearing.

Fig. 12 is a plan view of embodiment 3 of the metal detector.

Fig. 13 is a side view of embodiment 3 of the metal detector.

Fig. 14 is a plan view of embodiment 4 of the metal detector.

Fig. 15 is a side view of embodiment 4 of the metal detector.

Fig. 16 is an elevation view of embodiment 5 of the metal detector.

Fig. 17 is a side view of embodiment 5 of the metal detector.

Fig. 18 is a plan view of embodiment 6 of the metal detector.

Fig. 19 is a side view of embodiment 6 of the metal detector.

Fig. 20 is a front view of embodiment 6 of the metal detector.

Fig. 21 is a sectional view of the search coil unit of embodiment 6.

Fig. 22 is a sectional view of a metal frame used in embodiment 6.

Fig. 23 is a plan view of embodiment 7 of the metal detector.

Fig. 24 is a front view of embodiment 7 of the metal detector.

Fig. 25 is a plan view of the 8 th embodiment of the metal detector.

Fig. 26 is a side view of the 8 th embodiment of the metal detector.

Fig. 27 is a front view of the 8 th embodiment of the metal detector.

Fig. 28 is a front view of the 9 th embodiment of the metal detector.

Fig. 29 is a side view of the 9 th embodiment of the metal detector.

Fig. 30 is a bottom view of the 9 th embodiment of the metal detector.

Fig. 31 is a side view of the 10 th embodiment of the metal detector.

Fig. 32 is a plan view of the 11 th embodiment of the metal detector.

Fig. 33 is a side view of embodiment 11 of the metal detector.

Fig. 34 is a rear view of the 12 th embodiment in which the metal detector is provided to the cloth inspecting machine (estimating).

Fig. 35 is a partial cross-sectional view of the 12 th embodiment with a metal detector positioned on the cloth inspecting machine.

Figure 36 is a rear view of the 13 th embodiment with the metal detector set on the cloth inspecting machine.

Fig. 37 is a partial cross-sectional view of the 13 th embodiment with a metal detector disposed on the cloth inspecting machine.

Fig. 38 is a side view of embodiment 14 of the metal detector configured by a general arrangement structure of the control panel and the motor.

Fig. 39 is a side view of the 14 th embodiment of the metal detector for taking measures against noise with respect to the arrangement structure of the control panel and the motor.

Detailed Description

(embodiment 1)

Fig. 1 shows a side view of a metal detector according to the present embodiment.

The metal detector of the present embodiment is called a horizontal installation type, and is disposed such that the detection surface of the search coil is substantially horizontal, and the object to be detected moves in the horizontal direction. The metal detector is a device for detecting whether or not a metal piece or the like is mixed in or attached to a long cloth as an object to be detected.

Themetal detector 20 is provided with two body frames 24 on both sides in the width direction (direction on a horizontal plane orthogonal to the transfer direction of the cloth 10) along the transfer direction of thecloth 10. A plurality oflegs 26 are respectively installed at the lower portion of eachbody frame 24 so that thebody frame 24 is positioned at a predetermined height from the ground.

A plurality ofrollers 28 are provided to connect the body frames 24. In the present embodiment, a drivingbelt 31 is stretched over eachroller 28, and therollers 28 are rotated by driving thebelt 31 by a driving device, not shown. Thecloth 10 can be transferred in the transfer direction by rotating theroller 28 in the transfer direction.

Thedetection coil 22 is provided so as to connect the body frames 24.

Thesearch coil 22 is a rectangular parallelepiped shape elongated in the width direction, and has an upper surface in contact with thecloth 10 to form adetection surface 22a for detecting a metal. Further, thecloth 10 may not contact thedetection surface 22 a.

Thesearch coil 22 can detect the presence or absence of metal by a change in the magnetic field generated by the coil housed inside due to the metal.

In the present embodiment, asearch coil unit 32 is provided in which thesearch coil 22 is integrated with a shield member for reducing the influence of electromagnetic waves from the surroundings.

Fig. 2 shows a plan view of the search coil unit, fig. 3 shows a side view, and fig. 4 shows a front view.

Thesearch coil unit 32 includes thesearch coil 22, two conductor frames 34 positioned on both sides in the width direction of the search coil 22 (the direction on the horizontal plane orthogonal to the transfer direction of the cloth 10), andconductor coupling members 36 that couple the vicinities of both ends of eachconductor frame 34 to each other.

In the present embodiment, a panel made of stainless steel is used as theconductor frame 34. Further, theconductor coupling member 36 is a stainless steel decorative pipe.

The upper surface of theconductor coupling member 36 is disposed on the same plane as thedetection surface 22a of thesearch coil 22. In this way, by forming theconductor coupling member 36 as a decorative pipe made of stainless steel and forming the same plane as thedetection surface 22a of thesearch coil 22, thecloth 10 to be detected can be brought into contact with the upper surface of the decorative pipe, and the transfer of thecloth 10 can be guided.

Further, the panel as theconductor frame 34 may be made of iron, and a member made of stainless steel may be interposed at a connecting portion between the decorative pipe and theconductor frame 34.

Since stainless steel has an effect as an electrostatic shield and iron has an effect as a magnetic shield, theconductor frame 34 may be made of iron, and a member made of stainless steel may be interposed at a connecting portion between theconductor frame 34 and the decorative pipe.

The two conductor frames 34 and the twoconductor connecting members 36 are connected so as to surround the periphery of thesearch coil 22 in an ロ -shaped manner, thereby constituting a shield member. This reduces the influence of the surrounding electromagnetic waves by thesearch coil 22, thereby enabling detection of the metal.

As shown in fig. 4, both ends in the width direction of thesearch coil 22 are attached to theconductor frame 34 via vibration-proof rubbers 38.

This can insulate thesearch coil 22 itself from the shield member, and prevent external vibration from being transmitted to thesearch coil 22. Therefore, the malfunction of thesearch coil 22 can be further reduced.

Acover 40 for a matching transformer (not shown) is formed on the lower surface of thesearch coil 22.

Fig. 5 shows a side view of the search coil unit and the fuselage frame. With this configuration, thesearch coil unit 32 is attached to thebody frame 24 via the vibration-proof rubber 44.

With this configuration, it is possible to insulate thesearch coil unit 32 from noise current caused by interference flowing into the left and right body frames 24, and to prevent external vibration from being transmitted to thesearch coil unit 32. Therefore, the malfunction of thesearch coil 22 can be further reduced. However, thesearch coil unit 32 needs to be grounded at a single point with respect to the body frame 24 (reference numeral 46). This allows static electricity charged in thesearch coil unit 32 to be discharged from the single-point ground 46, and thus, the static electricity can be electrically stabilized.

In addition, the ground of thesearch coil 22 itself is independent of the ground of thesearch coil unit 32. Specifically, a ground wire (not shown) is connected to a control box (not shown) together with various electric wires such as a cable connected to thesearch coil 22.

As shown in fig. 6, thesearch coil unit 32 may be attached to thebody frame 24 without interposing a vibration-proof rubber therebetween.

With this configuration, thesingle point ground 46 shown in fig. 5 need not be provided.

(embodiment 2)

Fig. 7 shows a top view ofembodiment 2 of the metal detector, and fig. 8 and 9 show side views.

Note that the same components as those in embodiment 1 may be denoted by the same reference numerals and their description may be omitted.

In the present embodiment, a shield member is provided around thesearch coil unit 32.

That is, the 2 ndconductor coupling members 42 that are coupled to each other so as to conduct the body frames 24 with each other are provided at two locations on the upstream side and the downstream side in the transfer direction of thecloth 10 with respect to thesearch coil unit 32 and closer to thesearch coil 22 than theroller 28.

The two body frames 24 and the two 2 ndconductor coupling members 42 are coupled so as to surround the periphery of thesearch coil unit 32 in the form of japanese katakana ロ, thereby constituting a shield member. This reduces the influence of the surrounding electromagnetic waves by thesearch coil 22, thereby enabling detection of the metal.

The 2 ndconductor coupling member 42 is preferably a stainless steel decorative pipe as in theconductor coupling member 36, and is flush with thedetection surface 22a of thesearch coil 22. With this configuration, thecloth 10 to be detected can be brought into contact with the upper surface of the decorative pipe to guide the transfer of thecloth 10.

In addition, as in embodiment 1, the decorative pipe as the 2 ndconductor coupling member 42 may be made of iron, and a member made of stainless steel may be interposed at a connecting portion between the decorative pipe and thebody frame 24.

In order to reliably convey thecloth 10, a roller is preferably used as the 2 ndconductor coupling member 42.

As the roller structure, theroller shaft 42a may be fixed to thebody frame 24, and a portion in contact with thecloth 10 may be freely rotated via a bearing or the like.

Instead of arranging thecloth 10 on the upper surface of the 2 ndconductor coupling member 42, thecloth 10 may be arranged on the lower surface as shown in fig. 9. In this case, thecloth 10 is disposed on theroller 28 disposed outside the 2 ndconductor coupling member 42 so as to be in contact with the upper surface thereof.

By disposing thecloth 10 in this manner, an appropriate tension can be applied to thecloth 10.

Next, a description will be given of a portion for insulating the bearing as a structure common to embodiment 1 andembodiment 2.

In the rollers of fig. 1, 5 to 6, and 8 to 9, a bearing (not shown in fig. 1, 5 to 6, and 8 to 9) having a plurality of metal balls built therein is generally used as a bearing of the rotating shaft.

However, an oil film of grease adheres to the bearing, and an electrically unstable state occurs in which a current flows or does not flow due to the rotation of the bearing.

When a high-frequency current caused by a leakage magnetic field of thesearch coil 22 flows into the electrically unstable bearing, the magnetic field of thesearch coil 22 is secondarily disturbed, which causes a malfunction.

However, by insulating the bearing from thebody frame 24, the generation of an electrically unstable electric network is prevented and malfunction does not occur.

Fig. 10 shows an insulating structure of the bearing.

Therotary shaft 29 of theroller 28 is supported by abearing 49. Thebearing 49 is mounted on the upper surface of thebody frame 24.

Thebearing 49 is mounted on thebody frame 24 by abolt 50 and anut 51.

A bolt throughhole 52 is formed at a predetermined position of thebody frame 24 to penetrate vertically. A bolt throughhole 54 penetrating vertically is also formed in thebearing 49, and thebolt 50 is inserted while the bolt throughhole 52 of thebody frame 24 and the bolt throughhole 54 of thebearing 49 are communicated with each other.

Further, an insulatingbush 56 is provided to communicate the bolt throughhole 52 of thebody frame 24 with the bolt throughhole 54 of thebearing 49.

The insulatingbush 56 has a cylindrical portion for insulating the inner wall surfaces of the bolt throughholes 52 and 54 from thebolt 50, and a flange portion for insulating thenut 51 from thebody frame 24.

Further, an insulatingplate 58 is interposed between the bearing 49 and thebody frame 24. In this way, since the bearing 49 can be insulated from thebody frame 24 by the insulatingbush 56 and the insulatingplate 58, it is possible to prevent the formation of an electrically unstable electric network and reduce the occurrence of malfunctions.

Fig. 11 shows another embodiment of the insulating structure of the bearing.

In the configuration of fig. 11, the insertion direction of the bolt for mounting the bearing is directed horizontally, and the basic insulation method is the same as that of fig. 10.

That is, a bolt throughhole 52 penetrating in the horizontal direction is formed at a predetermined position of thebody frame 24. A bolt throughhole 54 penetrating in the horizontal direction is also formed in thebearing 49, and thebolt 50 is inserted while the bolt throughhole 52 of thebody frame 24 and the bolt throughhole 54 of thebearing 49 are communicated with each other.

Further, an insulatingbush 56 is provided to communicate the bolt throughhole 52 of thebody frame 24 with the bolt throughhole 54 of thebearing 49.

The insulatingbush 56 has a cylindrical portion for insulating the inner wall surfaces of the bolt throughholes 52 and 54 from thebolt 50, and a flange portion for insulating the head portion of thebolt 50 from thebody frame 24.

Further, an insulatingplate 58 is interposed between the bearing 49 and thebody frame 24.

In this way, since the bearing 49 can be insulated from thebody frame 24 by the insulatingbush 56 and the insulatingplate 58, it is possible to prevent the formation of an electrically unstable electric network and reduce the occurrence of malfunctions.

Even when the bearing portion is insulated as in fig. 10 and 11, it is preferable that any one end portion of therotation shaft 29 of theroller 28 in the width direction is electrically connected to thebody frame 24. This allows static electricity generated in theroller 28 to be discharged to thebody frame 24.

In the case of insulating the bearing portion of one end portion of theroller 28 as in fig. 10, it is preferable to dispose a conductive plate (for example, an aluminum plate or the like) having the same thickness as the insulatingplate 58 in a portion of the other end portion of theroller 28 located between the bearing 49 and thebody frame 24. By such an arrangement, theroller 28 can be rotated and thecloth 10 can be stably transferred with the height of theroller 28 being uniform.

(embodiment 3)

Fig. 12 is a plan view of embodiment 3, and fig. 13 is a side view.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

Inembodiments 1 and 2, the search coil unit in which the search coil and the shield member are integrated is attached to the body frame, but in the present embodiment, the search coil unit is not unitized.

In the present embodiment, both ends in the width direction of thesearch coil 22 are attached to the upper surface of thebody frame 24 via the vibration-proof rubber 44. Thus, thesearch coil 22 can be insulated from noise current caused by interference flowing into the right and left body frames 24, and external vibration is not transmitted to thesearch coil 22. Therefore, the number of malfunctions of thesearch coil 22 can be reduced.

A ground line (not shown) that grounds thesearch coil 22 itself is connected to a control box (not shown) together with various electric wires such as a cable connected to thesearch coil 22.

The shield member of the present embodiment includes each of the body frames 24 and twoconductors 60 connecting the body frames 24 at respective positions on the upstream side and the downstream side of thesearch coil 22 along the transfer direction of thecloth 10. Theconductors 60 and the body frames 24 are mounted in electrical communication.

The two body frames 24 and the twoconductors 60 are connected so as to surround the periphery of thesearch coil unit 32 in the form of japanese katakana ロ, thereby constituting a shield member. This reduces the influence of the surrounding electromagnetic waves by thesearch coil 22, thereby enabling detection of the metal.

Theconductor 60 is preferably a stainless steel decorative tube and is flush with thedetection surface 22a of thesearch coil 22. With this configuration, thecloth 10 to be detected can be brought into contact with the upper surface of the decorative pipe to guide the transfer of thecloth 10.

As in the case ofembodiments 1 and 2, the decorative pipe serving as theconductor 60 may be made of iron, and a member made of stainless steel may be interposed at a connecting portion between the decorative pipe and thebody frame 24.

(embodiment 4)

Fig. 14 is a plan view of embodiment 4, and fig. 15 is a side view.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

The present embodiment is also configured such that the search coil and the shield member are not unitized as in the above-described embodiment 3, but is configured such that a roller is further provided.

In the present embodiment, therollers 28 are provided on the upstream side and the downstream side in the transfer direction of theconductor 60, respectively. Theroller 28 is driven by a driving device, not shown, to transfer thecloth 10.

The roller needs to insulate the bearing portion as shown in fig. 10 and 11. In order to discharge static electricity, it is preferable that either side of therotation shaft 29 of theroller 28 is electrically connected to thebody frame 24.

(embodiment 5)

Fig. 16 is a vertical view of embodiment 5, and fig. 17 is a side view.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

The present embodiment is a structure in which the search coil and the shield member are not unitized, and is of a vertical installation type.

In the vertical installation type, the detection surface of the search coil is disposed so as to be perpendicular to the detection surface, and thecloth 10 as the object to be detected is moved in the vertical direction.

Themetal detector 20 is provided with two body frames 24 on both sides in the width direction (direction on a vertical plane orthogonal to the transfer direction of the cloth 10) along the transfer direction of thecloth 10.

Aroller 62 is provided to connect the lower end of thebody frame 24. Further, abeam 63 extending in the horizontal direction is provided at the upper end of thebody frame 24, and aroller 64 is provided on thebeam 63.

Thecloth 10 as the object to be detected moves in the horizontal direction along thebeam 63, is stretched over theroller 64 so that the transfer direction is vertically downward, is stretched over theroller 62 after passing through thesearch coil 22, and is changed to the horizontal direction.

Thesearch coil 22 is provided so as to connect the body frames 24.

Thesearch coil 22 is a rectangular parallelepiped shape elongated in the width direction, and has a side surface in contact with thecloth 10 to form adetection surface 22a for detecting a metal.

Further, a plurality ofconductors 60 that connect the body frames 24 are provided above and below thesearch coil 22. In the present embodiment, 1conductor 60 is attached to each tip of anarm 68 attached to eachbody frame 24 in the vicinity of the upper portion of thesearch coil 22 and in the vicinity of the lower portion of thesearch coil 22. Thearm 68 is provided to protrude from thebody frame 24 toward thedetection surface 22a of thesearch coil 22. Further, since thearm 68 is also formed of a conductor, theconductor 60 and eachbody frame 24 are mounted in an electrically conductive manner.

The two body frames 24 and the twoconductors 60 are connected so as to surround the periphery of thesearch coil 22 in the form of japanese katakana ロ, thereby constituting a shield member. This reduces the influence of the surrounding electromagnetic waves by thesearch coil 22, thereby enabling detection of the metal.

A ground line (not shown) that grounds thesearch coil 22 itself is connected to a control box (not shown) together with various electric wires such as a cable connected to thesearch coil 22.

In the present embodiment, a reinforcingpipe 70 is further provided to connect the side surfaces of thebody frame 24 to each other at a position above and below eachconductor 60.

The reinforcingtube 70 is also made of an electrically conductive material, and thus a shield member is configured in the same manner as theconductor 60 described above.

That is, the two body frames 24 and the two reinforcingpipes 70 are connected so as to surround the periphery of thesearch coil unit 22 in the form of japanese katakana ロ, thereby constituting a shield member. This allows thedetection coil 22 to detect a metal without being affected by surrounding electromagnetic waves.

In the present embodiment, acloth guide 72 is provided between thelower conductor 60 and the lower reinforcingtube 70.

By providing thecloth guide 72, the tension of thecloth 10 is maintained, and wrinkles and the like can be prevented from occurring.

In addition, even in the case of the vertical installation type as in the present embodiment, a configuration may be adopted in which a search coil unit in which a search coil and a shield member are unitized is attached to a body frame.

(embodiment 6)

Fig. 18 is a plan view of embodiment 6, fig. 19 is a side view, and fig. 20 is a front view. Fig. 21 is a cross-sectional view of the search coil, and fig. 22 is a side view of a gantry of the search coil.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

The present embodiment is configured such that the conductor constituting the shield member is attached along both the front side surface and the rear side surface of the search coil, and is of a horizontal installation type.

Thesearch coil 22 is a rectangular parallelepiped shape elongated in the width direction, and has an upper surface close to thecloth 10 in contact with or without contact, and is configured as adetection surface 22a for detecting a metal.

Thelong conductor 74 having a length longer than the width direction length of thesearch coil 22 is attached to each of the front side surface (upstream side in the direction of transfer of the object) and the back side surface (downstream side in the direction of transfer of the object) of thesearch coil 22 via an insulatingplate 124. In order to have a compact structure, theconductor 74 is preferably in the form of a flat plate that can be brought into close contact with the side surface of the search coil 22 (with the insulatingplate 124 interposed therebetween), rather than in the form of a cylinder.

For example, an L-letter shaped angle iron (hereinafter, also referred to as an L-letter shaped angle iron 74) may be used as theconductor 74. In addition, the insulatingplate 124 may be a thin bakelite plate having a thickness of about 2 mm. One side of the L-shaped angle iron is fixed to the front side surface or the rear side surface of thesearch coil 22 via an insulatingplate 124 by an insulatingplastic bolt 76 or the like. The lower surface of the other side of the L-letter shaped angle iron is fixed to thebody frame 24 via a vibration-proof rubber 44.

The length of theconductor 74 in the width direction is longer than the length of thesearch coil 22 in the width direction. The ends of theconductor 74 are connected to each other by aconductor tube 126. Theconductor pipe 126 may be a stainless steel pipe. Further, since theconductor 74 and theconductor tube 126 are fixed by themetal bolt 77, theconductor 74 and theconductor tube 126 can be surely conducted.

With this configuration, the periphery of thesearch coil 22 is connected by theconductor 74 and theconductor tube 126 so as to form the shield member in japanese katakana ロ, but the shield member is insulated from thesearch coil 22.

However, the end of theconductor 74 is attached to thebody frame 24 via theanti-vibration rubber 44. Thus, theconductors 74 are insulated from thefuselage frame 24. Thus, theconductor 74 and thefuselage frame 24 require a single point of ground (reference numeral 46). This allows static electricity charged in theconductor 74 and theconductor tube 126 to be discharged from the single-point ground 46, and thus, the static electricity can be electrically stabilized.

In addition, the ground of thesearch coil 22 is independent of the ground of theconductor 74 and theconductor tube 126. Specifically, a ground wire (not shown) is connected to a control box (not shown) together with various electric wires such as a cable connected to thesearch coil 22.

In the present embodiment, the shield member is configured by connecting theconductor 74 and theconductor tube 126 so as to surround the periphery of thesearch coil 22 in the form of japanese katakana ロ. This reduces the influence of the surrounding electromagnetic waves by thesearch coil 22, thereby enabling detection of the metal. Further, since thesearch coil 22 and theconductor 74 are fixed to each other with theplastic bolt 76 interposed therebetween by the insulatingplate 124, such an operational effect can be obtained with an extremely simple structure.

Thesearch coil 22 is held on the side and bottom surfaces by aframe 45 having an upper surface opening and a cross section in the shape of japanese katakana コ as shown in fig. 22.

One side of the metal L-letter angle 74 is attached to both side surfaces of theframe 45 via an insulatingplate 124 such as bakelite by using an insulatingbolt 61 and an insulatingnut 65 made of plastic or the like. The other side of the L-letter shapedangle 74 is provided with a vibration-proof rubber 44.

Thus, thesearch coil 22 is insulated from the letter L-shapedangle iron 74.

Alongitudinal receiving groove 69 is formed in a side surface of theframe 45 along the longitudinal direction. The receivinggroove 69 receives an insulatingbolt head 61a for attaching the L-letter angle 74. Therefore, the mounting position of the L-letter shapedangle 74 can be moved along the longitudinal direction of theframe 45.

Further, ahousing hole 87 having a vertically long circular cross section is formed along the longitudinal direction in the bottom surface of thechassis 45. The housing hole is formed to be able to house cables such as coaxial cables connected to thesearch coil 22.

In the present embodiment, the description has been given of the embodiment in which theconductor 74 and theconductor tube 126 are connected so as to surround the periphery of thesearch coil 22 in the shape of japanese katakana ロ, thereby forming the shielding member, but the connection of theconductors 74 is not limited to the conductor tube.

For example, both end portions of theconductor 74 may be connected to each other by a conductor plate (not shown). In this case, since the conductor plate can be disposed below the bottom surface of thesearch coil 22, the length of thesearch coil 22 can be set to the same length as the length of theconductor 74.

Note that, the both end portions of theconductor 74 may be connected to each other by L-letter shaped angle iron instead of the conductor plate (not shown).

(7 th embodiment)

Fig. 23 is a plan view of embodiment 7, and fig. 24 is a front view.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

This embodiment is a structure in which a decorative pipe is attached in addition to the structure of embodiment 6, and is a horizontally disposed type.

Theconductor 74, which is longer than thedetection coil 22 in the width direction, is attached to each of the front side surface (upstream side in the transfer direction of the object) and the back side surface (downstream side in the transfer direction of the object) of thedetection coil 22 via an insulatingplate 124. As in the above-described embodiment, a thin bakelite plate having a thickness of about 2mm or the like may be used for the insulatingplate 124, and as in the above-described embodiment, an L-letter-shaped angle iron may be used for theconductor 74. One side of the L-shaped angle iron is fixed to the front side surface or the rear side surface of thesearch coil 22 by an insulatingplastic bolt 76 or the like. The lower surface of the other side of the L-letter shaped angle iron is fixed to theconductor frame 34 via a vibration-proof rubber 44. Thebody frame 24 is disposed below theconductor frame 34.

The ends of theconductor 74 are connected to each other by aconductor tube 126 such as a stainless steel tube. Therefore, theconductor 74 and theconductor tube 126 surround the periphery of thesearch coil 22 in a shape of japanese katakana ロ to form a shield member. At this time, theconductor 74 is attached to the probe coil via the insulatingplate 124, and theconductor tube 126 is disposed with a gap from theprobe coil 22, and therefore, is constituted by theconductor 74 and theconductor tube 126. The shield member is insulated from thesearch coil 22.

Twoconductors 78 that connect the conductor frames 34 are provided at positions on the upstream side and the downstream side of thesearch coil 22 in the transfer direction of thecloth 10. Theconductors 78 and the conductor frames 34 are mounted in electrical communication.

In the present embodiment, the shield member is configured by two conductor frames 34 and twoconductors 78 being connected so as to surround the circumference of thesearch coil 22 in the form of japanese katakana ロ, and the shield member is configured doubly by twoconductors 74 and twoconductor tubes 126 being connected so as to surround the circumference of thesearch coil 22 in the form of japanese katakana ロ as described above.

With such a configuration, thesearch coil 22 can further reduce the influence of the surrounding electromagnetic waves, and can detect a metal.

Theconductor 78 is preferably a stainless steel decorative tube, and is preferably flush with thedetection surface 22a of thesearch coil 22. With this configuration, thecloth 10 to be detected can be brought into contact with the upper surface of the decorative pipe to guide the transfer of thecloth 10.

As in the other embodiments, the decorative pipe as theconductor 78 may be made of iron, and a member made of stainless steel may be interposed at the connecting portion between the decorative pipe and theconductor frame 34.

As in embodiment 6, the member for connecting theconductors 74 to each other is not limited to a conductor tube.

For example, both end portions of theconductor 74 may be connected to each other by a conductor plate (not shown). In this case, since the conductor plate can be disposed below the bottom surface of thesearch coil 22, the length of thesearch coil 22 can be set to the same length as the length of theconductor 74.

Note that, the both end portions of theconductor 74 may be connected to each other by L-letter shaped angle iron instead of the conductor plate (not shown).

(embodiment 8)

Fig. 25 shows a plan view, fig. 26 shows a side view, and fig. 27 shows a front view of the 8 th embodiment.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

The present embodiment is configured to shield the search coil in half, and is of a horizontal installation type. In the case of the present embodiment, the support portion and the cover portion described later correspond to the shield member.

At both ends in the width direction of thesearch coil 22,support portions 80 extending upward on the front surface side and the back surface side of thesearch coil 22 are provided. Thesupport portion 80 may be a stainless steel panel or the like.

Acover 82 that covers the upper side of thesearch coil 22 is provided above thedetection surface 22a of thesearch coil 22. Four corners of thecover 82 are fixed to upper ends of the 4support portions 80. Thehood 82 is generally the same as the probe coil in the gantry of fig. 22, but a panel made of stainless steel or the like may be used.

Further, a vibration-proof rubber 44 is provided on the lower surface of eachsupport portion 80, and eachsupport portion 80 is fixed to a not-shown body frame via the vibration-proof rubber 44 in an insulated manner.

The object to be detected enters the gap between thedetection surface 22a of thesearch coil 22 and thecover 82, and the presence or absence of metal can be detected.

A high-frequency magnetic field is formed on thedetection surface 22a of thesearch coil 22, and a leakage magnetic field exists around thesearch coil 22. In the present embodiment, thesearch coil 22 can be half-shielded by disposing thesupport portions 80 as conductors at both ends in the width direction of thesearch coil 22 and disposing thecover portions 82 as conductors above thedetection surface 22 a. Therefore, the variation of the leakage magnetic field around thesearch coil 22 due to the influence of the surrounding electromagnetic wave can be reduced, and stable detection can be performed.

(embodiment 9)

Fig. 28 shows a front view, fig. 29 shows a side view, and fig. 30 shows a bottom view of the 9 th embodiment.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

The present embodiment is a structure in which the search coil is half-shielded, and is of a vertical installation type. In the case of the present embodiment, the support portion and the cover portion described later correspond to the shield member.

In the vertical installation type, thedetection surface 22a of thesearch coil 22 is disposed so as to be substantially vertical, and thecloth 10 as the object to be detected is moved in the vertical direction.

At both ends in the width direction of thesearch coil 22,support portions 80 andsupport portions 84 are provided, which extend forward on the upper surface side and the lower surface side of thesearch coil 22, respectively. Thesupport portion 84 may be a stainless steel panel.

Acover 86 that covers the front of thesearch coil 22 is provided in front of thedetection surface 22a of thesearch coil 22. Thecover 86 is fixed at four corners thereof to the distal ends of the twosupport portions 80 and the distal ends of the twosupport portions 84. Thehood 86 is generally the same as theprobe coil 22 as shown in fig. 22, but a panel made of stainless steel or the like may be used.

Further, a vibration-proof rubber 44 is provided on the lower surface of eachsupport portion 84, and eachsupport portion 84 is fixed to a not-shown body frame via the vibration-proof rubber 44 in an insulated manner.

The object to be detected enters the gap between thedetection surface 22a of thesearch coil 22 and thecover 86, and the presence or absence of metal can be detected.

A high-frequency magnetic field is formed on thedetection surface 22a of thesearch coil 22, and a leakage magnetic field exists around thesearch coil 22. In the present embodiment, thesearch coil 22 can be half-shielded by disposing thesupport portions 80 and 84 as conductors at both ends in the width direction of thesearch coil 22 and disposing thecover portion 86 as a conductor in front of thedetection surface 22 a. Therefore, the variation of the leakage magnetic field around thesearch coil 22 due to the influence of the surrounding electromagnetic wave can be reduced, and stable detection can be performed.

(embodiment 10)

Fig. 31 shows a side view of the 10 th embodiment.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

In the present embodiment, a decorative pipe is combined with the half-shielded search coil described inembodiment 8.

Thesupport portion 80 of the half-shieldedsearch coil 22 is attached to the 1st bracket 88 via the vibration-proof rubber 44.

Further, a 2nd bracket 89 is mounted on thebody frame 24. The half-shieldedsearch coil 22 is fixed to thebody frame 24 by mounting the 1st bracket 88 on the 2nd bracket 89. In the present figure, since the 1st bracket 88 is attached to the 2nd bracket 89 obliquely, the half-shieldedsearch coil 22 is shown as an example in which thedetection surface 22a is attached to thebody frame 24 obliquely.

Conductors 90 are arranged on the upstream side and the downstream side in the transfer direction of the object to be detected (cloth 10) of the half-shieldedsearch coil 22. Theconductor 90 is preferably a stainless steel decorative tube.

Eachconductor 90 is attached to each of thebrackets 92a, 92b disposed on the upper surface of thebody frame 24. In the present embodiment, theholder 92a on the upstream side in the transfer direction of thecloth 10 is arranged higher than theholder 92b on the downstream side in the transfer direction of thecloth 10.

In order to guide theconductor 90 to thecloth 10, theupstream conductor 90 and thedownstream conductor 90 are mounted on therespective holders 92a, 92b at different heights according to the inclination angles of the detection surfaces 22a of the inclined search coils 22. The upper surface of theupstream conductor 90, thedetection surface 22a, and the upper surface of thedownstream conductor 90 are disposed on the same plane.

Eachconductor 90 is fixed to eachbracket 92a, 92b by a U-letter shaped fixingmetal fitting 94.

Theholders 92a, 92b are made of a material having high conductivity, and theconductors 90 and theholders 92a, 92b are electrically connected to each other. The fixingmetal fittings 94 are also made of a conductive material.

With such a configuration, in the present embodiment, the two body frames 24 and the twoconductors 90 are coupled so as to surround the periphery of the half-shieldedsearch coil 22 in the form of japanese katakana ロ, thereby configuring a shielding member. Thus, the half-shieldedsearch coil 22 can further reduce the influence of the surrounding electromagnetic waves, and can detect a metal.

In the present embodiment,rollers 96 are provided on the upstream side and the downstream side in the transfer direction of theconductor 90, respectively. Theroller 96 is driven by a driving device not shown in the figure to transfer thecloth 10.

The roller needs to insulate the bearing portion as shown in fig. 10 and 11. In order to discharge static electricity, it is preferable that any one end of the rotation shaft, not shown, of theroller 96 is electrically connected to thebody frame 24.

Further, the farther theroller 96 is from the search coil, the less influence of the malfunction of thesearch coil 22 due to the rotation of theroller 96. Therefore, when the distance between theroller 96 and thesearch coil 22 is large, theroller 96 may not be insulated.

(embodiment 11)

Fig. 32 is a plan view of the 11 th embodiment, and fig. 33 is a side view of the 11 th embodiment.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

In the present embodiment, the half-shielded search coil described inembodiment 8 is further integrated with a shield member to form a search coil unit.

The half-shieldedsearch coil 22 has the same configuration as the search coil shown in fig. 25 to 27, and the configuration thereof will not be described in detail here.

Thesearch coil unit 98 includes the half-shieldedsearch coil 22, two conductor frames 130 positioned on both sides in the width direction of the half-shieldedsearch coil 22, and aconductor coupling member 132 coupling the vicinities of both end portions of eachconductor frame 130 to each other.

In the present embodiment, theconductor frame 130 is a panel made of stainless steel, for example. Further, theconductor coupling member 132 is a stainless steel decorative pipe.

The upper surface of theconductor coupling member 132 is disposed so as to be flush with thedetection surface 22a of thesearch coil 22. By forming theconductor coupling member 132 as a decorative tube made of stainless steel and forming the same plane as thedetection surface 22a of thesearch coil 22 in this manner, thecloth 10 to be detected can be brought into contact with the decorative tube, and the transfer of thecloth 10 can be guided.

As in the above embodiments, the decorative pipe serving as theconductor coupling member 132 may be made of iron, and a member made of stainless steel may be interposed at the connecting portion between the decorative pipe and theconductor frame 130.

The two conductor frames 130 and the twoconductor connecting members 132 are connected so as to surround the periphery of the half-shieldedsearch coil 22 in the form of japanese katakana ロ, whereby the half-shieldedsearch coil 22 can further reduce the influence of electromagnetic waves around the detection coil and detect metal.

Further, both ends in the width direction of the half-shieldedsearch coil 22 are attached to theconductor frame 130 via the vibration-proof rubber 44.

This can insulate the half-shieldedsearch coil 22 itself from the shield member, and prevent external vibration from being transmitted to the half-shieldedsearch coil 22. Thus, thesearch coil 22 is doubly shielded, and the double shielding can reduce the malfunction of thesearch coil 22.

In the above-described embodiment of the half-shieldedsearch coil 22, thecover portions 82 and 86 may be shaped to cover not only the side surface of thesearch coil 22 facing thedetection surface 22a but also the side surface of thesearch coil 22.

In this case, it is preferable that holes having such a size that thecloth 10 can be inserted are formed in the side surfaces of thecover portions 82 and 86. Moreover, since thecover portions 82 and 86 are themselves fixed to thesearch coil 22, thesupport portion 80 is not necessary in this case.

(embodiment 12)

Fig. 34 shows a rear view of the 12 th embodiment, and fig. 35 shows a partial sectional view of the 12 th embodiment.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

In the present embodiment, the search coil is attached to the cloth inspecting machine.

Thecloth inspecting apparatus 110 is an apparatus for visually inspecting an object to be inspected such as cloth by an inspector, and has anillumination device 112 disposed on the back side thereof and is configured to convey the cloth in front of theillumination device 112.

Theillumination device 112 of thecloth inspecting machine 110 is disposed between two cloth inspecting machine frames 114 disposed at a predetermined interval and extending in the vertical direction. The upper ends of the two cloth inspection machine frames 114 are joined by across frame 116 extending in the transverse direction. The clothinspection machine frame 114 is constructed of a conductive material.

Thesearch coil 22 is attached between two cloth inspection frames 114 extending in the vertical direction above thelighting device 112 via the vibration-proof rubber 44.

Specifically, twoanti-vibration rubbers 44 are provided on both width-direction end portions of thesearch coil 22 so as to face the inner surface of the cloth inspectingmachine frame 114 extending in the vertical direction, respectively, and both width-direction end portions of thesearch coil 22 are fixed to the inner surface of the cloth inspectingmachine frame 114 extending in the vertical direction bybolts 118 and the like provided on the anti-vibration rubbers 44.

Above and below thesearch coil 22,coupling members 116 are provided, and thecoupling members 116 couple the cloth inspectingmachine frame 114 extending in the vertical direction. Each connectingmember 116 is made of a conductive material such as iron, and is configured to surround the periphery of thesearch coil 22 in a shape of japanese katakana ロ together with the twocloth inspecting frames 114.

With such a configuration, thesearch coil 22 reduces the influence of the surrounding electromagnetic waves, and can detect a metal.

Thedetection surface 22a of thesearch coil 22 may be disposed on the same plane as thesurface panel 122 of thecloth inspecting machine 110, or thedetection surface 22a of thesearch coil 22 may protrude forward by about 5mm from thesurface panel 122 of thecloth inspecting machine 110.

(embodiment 13)

Fig. 36 shows a rear view of the 13 th embodiment, and fig. 37 shows a partial sectional view of the 13 th embodiment.

Note that the same reference numerals are given to the same components as those in the above embodiments, and the description thereof may be omitted.

In the present embodiment, the probe coil and the shield member having the structure described in embodiment 6 are attached to a cloth inspecting machine.

Thecloth inspecting apparatus 110 of the present embodiment is similar to that of embodiment 12 in that thelighting device 112 and thesearch coil 22 are provided between two cloth inspecting apparatus frames 114 extending in the vertical direction.

Theconductor 74 is attached to each of the lower surface side surface and the upper surface side surface of thesearch coil 22 via an insulatingplate 124. The insulatingplate 124 may be a thin bakelite plate having a thickness of about 2 mm.

Theconductor 74 may be, for example, an L-letter shaped angle iron. One side of the L-shaped angle iron is fixed to the side surface on the lower surface side or the side surface on the upper surface side of thesearch coil 22 by an insulating plastic bolt or the like.

The length of theconductor 74 in the width direction is longer than the length of thesearch coil 22 in the width direction, and the ends of theconductor 74 are connected to each other by theconductor frame 100.

With this configuration, the periphery of thesearch coil 22 is connected to theconductor 74 and theconductor frame 100 so as to be surrounded by the japanese katakana ロ, thereby forming a shield member. This reduces the influence of the surrounding electromagnetic waves by thesearch coil 22, thereby enabling detection of the metal.

Thesearch coil 22 is attached between two cloth inspection frames 114 extending in the vertical direction above thelighting device 112 via the vibration-proof rubber 44.

Specifically, the vibration-proof rubber 44 facing the inner surface of thecloth inspecting frame 114 extending in the vertical direction and the vibration-proof rubber 44 facing downward are provided at both ends in the width direction of thesearch coil 22, and are fixed to thecloth inspecting frame 114 by bolts or the like provided to the respective vibration-proof rubbers 44.

Each clothinspection machine frame 114 is provided with aprojection 113 projecting inward (in a direction facing each other). Thesearch coil 22 has, on the upper surface of theprojection 113, the vibration-proof rubber 44 disposed downward, of the vibration-proof rubbers 44 attached to both ends thereof.

Above and below thesearch coil 22, there are provided couplingmembers 120 for coupling the cloth inspectingmachine frame 114 extending in the up-down direction with thecoupling members 120. Each connectingmember 120 is made of a conductive material such as iron, and is configured to surround the periphery of thesearch coil 22 in a shape of japanese katakana ロ together with the twocloth inspecting frames 114.

With such a configuration, thesearch coil 22 can further reduce the influence of the surrounding electromagnetic waves, and can detect a metal.

(embodiment 14)

In the present embodiment, the arrangement of thecontrol panel 140 will be described with reference to fig. 38 to 39.

Thesearch coil unit 32 shown in fig. 38 to 39 is the same as the search coil unit described in embodiment 1, and therefore, the description of thesearch coil unit 32 is omitted. In addition, the same reference numerals may be given to the same components as those described above for other components, and the description thereof may be omitted.

Thecontrol panel 140 incorporates a programming device and the like for controlling the feeding of the cloth.

When the metal piece or the like is detected in thecloth 10, thesearch coil unit 32 outputs a control signal to thecontrol panel 140. The control signal may also be a 1-time trigger pulse. Thecontrol panel 140 is provided to stop the feeding of thecloth 10 or perform other control when receiving a control signal of thesearch coil unit 32.

Fig. 38 shows a method of attaching thecontrol panel 140 in general.

Thesearch coil unit 32 is disposed on the upper surface of thebody frame 24, and thebody frame 24 is disposed at a predetermined height by thelegs 26.

Further, theroller 28 for conveying thecloth 10 is rotated by the driving of themotor 142 by thebelt 31.

Themotor 142 is disposed on amotor installation section 144, and themotor installation section 144 includes a placement section 144a extending horizontally from theleg 26 and a support section 144b extending downward from thebody frame 24.

Wiring from a distribution board (not shown) to thecontrol panel 140 is routed along thelegs 26, and thecontrol panel 140 is attached to thelegs 26 below themotor installation portion 144.

Further, the wiring from thecontrol board 140 to themotor 142 is also routed along thelegs 26.

Fig. 39 shows a method of attaching thecontrol panel 140 in a state where measures against noise are taken with respect to fig. 38.

In fig. 39, the influence of noise is reduced by disposing thecontrol board 140 at a position separated from thebody frame 24 or theleg 26.

Further, an insulatingplate 146 is interposed between themotor 142 and themotor installation portion 144.

Further, the ground is independently obtained from theleg 26 and thecontrol board 140, respectively.

Themotor 142 is also grounded independently from theleg 26 and thecontrol board 140. Thebelt 31 of themotor 142 is made nonconductive.

In this way, by adopting the above-described configuration for the body frame, the leg portion, the motor, the control panel, and the like for installing thesearch coil unit 32, it is possible to prevent malfunction due to electromagnetic noise.

Claims (9)

1. A metal detector is characterized in that a metal detector is provided,

the metal detector includes:

a search coil having a rectangular parallelepiped main body, a coil for metal detection being housed inside the main body, a surface of the main body being a detection surface; and

a shield member disposed so as to surround the periphery of the search coil,

the detection coil is fixed on two machine body frames extending along the conveying direction of the detected object by a vibration-proof rubber as a non-conductor, and the detection coil is provided with a single-point grounding relative to the machine body frames so as to discharge the static electricity charged by the detection coil,

the shield member includes the body frames and two conductors respectively connecting the body frames at positions on the upstream side and the downstream side of the search coil along the transfer direction of the object.

2. The metal detector of claim 1,

the shield member has two conductor frames, to which both ends of the search coil in the longitudinal direction are fixed in a substantially central portion thereof in an insulated manner, and a conductor coupling member for coupling the vicinities of both ends of each of the conductor frames to each other,

the search coil is unitized with a shield member,

a search coil unitized with the shield member is mounted on the two body frames.

3. The metal detector of claim 2,

each of the conductor coupling members is formed of a cylindrical member, and a surface thereof is arranged on the same plane as a detection surface of the search coil.

4. The metal detector of claim 1,

the two conductors are rollers having metal shafts and assisting in the transfer of the object to be detected.

5. The metal detector of claim 1,

the shielding member comprises two conductors and two conductor tubes or plates,

the two conductors have flat plate-like portions attached to an upstream side surface and a downstream side surface of the detection coil in a transfer direction of the object to be detected via an insulating plate;

the two conductor pipes or the conductor plates connect end portions of the conductors to each other.

6. The metal detector according to any one of claims 2 to 4,

when a bearing is present between members that connect the body frames to each other, the bearing is insulated from the body frames.

7. The metal detector of claim 1,

the shield member has a cover portion that is disposed at a position facing at least the detection surface of the search coil with a predetermined gap therebetween and covers the search coil.

8. The metal detector of claim 7,

the metal detector has a plurality of support portions for fixing the cover portion to the search coil.

9. Metal detector according to claim 7 or 8,

the metal detector comprises two conductor frames having both ends of the search coil fixed in an insulating manner at substantially the center thereof in the longitudinal direction, and a conductor connecting member for connecting the vicinities of both ends of each of the conductor frames to each other,

the search coil to which the cover is attached is unitized by the conductor frame and the conductor coupling member,

the unitized search coil is mounted on the two fuselage frames.

Images