Shielding unit and x-ray inspection device

Abstract

To provide a shielding unit and an X-ray inspection device capable of improving space efficiency and passage of items.SOLUTION: A shielding unit 40 shields an entrance opening 4a by a support shaft 43 arranged horizontally near an upper end of the entrance opening 4a, and a plurality of metal shielding plates 50 that is aligned along the support shaft 43, and each of which has a base end part 51 supported by the support shaft 43 and suspended from the support shaft 43 in a freely swingable manner. Each shielding plate 50 extends in only one direction from the base end part 51, and has an upper bent part 55 (bent part 53) between the base end part 51 and a tip end part 52.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a shielding unit that prevents X-rays from leaking to the outside, and to an X-ray inspection apparatus. [Background technology]

[0002] Conventionally, X-ray inspection devices are known that include an X-ray leakage prevention member (such as a shielding curtain) for preventing X-ray leakage (for example, Patent Documents 1 and 2). In these devices, a horizontal shaft is provided that extends in a direction transverse to the direction in which the article is transported, and a plurality of shielding members that can swing around the horizontal shaft are suspended from the horizontal shaft. When an article (an object to be inspected or a container that contains the object) transported by the transport device comes into contact with the shielding members, the shielding members swing (or rotate). After the container or article has passed, the shielding members return to their original positions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3175410 [Patent Document 2] Patent No. 5337084 Summary of the Invention [Problem to be solved by the invention]

[0004] In the device described in Patent Document 1, the shielding member hangs vertically downward from the shaft (perpendicular to the conveying surface). In this case, the recoil of the shielding member has a large effect, which causes problems with the ease with which articles can pass through. In addition, in the device described in Patent Document 2, an area that acts as a balance weight is provided above the shaft. This area is provided with a bent portion that acts as a member to prevent backswing. In this case, the existence of an area above the shaft causes problems in terms of space efficiency.

[0005] An object of the present invention is to provide a shielding unit and an X-ray inspection apparatus that can improve space efficiency and also improve the passability of articles. [Means for solving the problem]

[0006] [1] One aspect of the present invention is a shielding unit that prevents X-rays irradiated onto an object from leaking from an opening in an inspection area, and shields the opening with a support shaft that is arranged horizontally near the upper end of the opening, and multiple metal shielding plates that are supported at their base ends by the support shaft and suspended from the support shaft so as to be able to swing freely, and are lined up along the support shaft, each of which extends in only one direction from the base end and has a bent portion between the base end and the tip end.

[0007] According to the shielding unit of [1], the opening is shielded by the support shaft and multiple metal shielding plates, preventing X-ray leakage. Each shielding plate extends only in one direction from the base end, so it does not protrude to the other side of the support shaft. This improves space efficiency on the other side of the support shaft. In addition, the bent portion allows the shape and center of gravity of the shielding plate to be adjusted. This reduces the recoil that the object receives from the shielding plate, improving the object's pass-through.

[0008] [2] An X-ray inspection device according to another aspect of the present invention includes a conveying unit that conveys an article, an X-ray irradiation unit that irradiates X-rays onto the article conveyed by the conveying unit, an X-ray detection unit that detects X-rays that have passed through the article, and the shielding unit described in claim 1. According to this configuration, in an X-ray inspection device that irradiates X-rays onto the article being conveyed, the opening is shielded, preventing X-rays from leaking outward in the conveying direction. This increases the degree of freedom in layout around the shielding unit. Furthermore, the passage of articles conveyed by the conveying unit is improved, thereby increasing the operational stability of the X-ray inspection device.

[0009] [3] In the X-ray inspection device of [2] above, the bending portion may include an upper bending portion disposed at a position higher than the midpoint between the base end and the tip end. This configuration ensures the length of the extension below the upper bending portion. It is possible to suitably pass through articles of various sizes (heights). Furthermore, the distance from the support shaft to the tip end can be shortened, thereby reducing the turning radius of each shielding plate. This allows for an increased installation density of shielding units in a limited section (even a narrow section) in the conveying direction.

[0010] [4] In the X-ray inspection device of [3] above, the upper bending portion may be located upstream of the center line of the support shaft in the conveying direction when the shielding plate is in the reference position where it is suspended without contacting the article. This configuration makes it easier to reduce the turning radius. It also makes it easier to adjust the center of gravity to suppress recoil.

[0011] [5] In the X-ray inspection device of any one of [2] to [4] above, the shielding unit may further include a rotation restricting part that restricts rotation of the shielding plate. With this configuration, unnecessary movement of the shielding plate (for example, swinging after an article has passed) can be restricted.

[0012] [6] In the X-ray inspection device of [5] above, the rotation restricting unit may act on the shielding plate so as to push up the shielding plate in the conveying direction when the shielding plate is in a reference position where it is suspended without contacting the article. With this configuration, the shielding plate is pushed up by the rotation restricting unit from the beginning, further improving the ease of passage of the article. [Effects of the Invention]

[0013] According to the present invention, it is possible to improve space efficiency and also improve the ease with which articles can pass through. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a front view of an X-ray inspection apparatus according to an embodiment of the present invention. [Figure 2]FIG. 2 is a side view of the X-ray inspection apparatus of FIG. [Figure 3] FIG. 3 is a front view showing the configuration of the transport unit and the shielding unit and its vicinity. [Figure 4] FIG. 4 is a perspective view showing the configuration of the upstream side portion of the transport section and the shielding unit. [Figure 5] FIG. 5 is a side view for explaining the arrangement of six shielding plates installed along the conveying direction. [Figure 6] 6(a) to 6(c) are side views showing the change in the attitude of the shielding plate when an article passes through it. [Figure 7] 7(a) to 7(c) are side views showing changes in the posture of the shielding plate according to the modified example when an article passes through the shielding plate. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted.

[0016] 1 and 2, the X-ray inspection apparatus 1 includes an apparatus main body 2, support legs 3, and a transport unit (transport section) 5. The support legs 3 support the apparatus main body 2. The apparatus main body 2 has a housing 9 made of a material capable of blocking electromagnetic waves such as X-rays. The housing 9 includes, for example, an upper part 9a having a display operation section 8 provided on the front surface, a back part 9b extending in the vertical direction, and a lower part 9c protruding forward from the back part 9b.

[0017] The X-ray inspection apparatus 1 includes an inspection unit 15 incorporated in an apparatus main body 2. The inspection unit 15 has an inspection chamber (inspection area) 4 provided at approximately the center in the height direction of the apparatus main body 2. The inspection chamber 4 is provided with, for example, a shielding box (not shown). The inspection unit 15 includes an X-ray irradiation unit 6 and an X-ray detection unit 7 housed in a housing 9 of the apparatus main body 2. The X-ray irradiation unit 6 is arranged in an upper part 9a of the housing 9, and the X-ray detection unit 7 is arranged in a lower part 9c of the housing 9. The inspection unit 15 further includes a control unit 10 provided, for example, in the upper part 9a of the housing 9.

[0018] When viewed from the upstream side in the transport direction A, the first wall 91 of the upper portion 9a, the second wall 92 of the back portion 9b, and the third wall 93 of the lower portion 9c form a U-shape that opens forward. The inspection chamber 4 is a substantially rectangular parallelepiped space surrounded by these walls. A rectangular entrance opening (opening) 4a is formed at the upstream end of the inspection chamber 4 in the transport direction A. A rectangular exit opening (opening) 4b is formed at the downstream end of the inspection chamber 4 in the transport direction A. The shape and size of the entrance opening 4a are the same as those of the exit opening 4b. The front of the inspection chamber 4 is covered by a shielding cover (not shown) that is opened and closed, for example, during maintenance.

[0019] The transport unit 5 transports the article G (see FIG. 6(b)) in a transport direction A. The transport unit 5 is installed so as to pass through the inspection chamber 4 in the transport direction A. In other words, the inspection unit 15 is installed so as to cover the transport unit 5.

[0020] The X-ray inspection device 1 generates an X-ray transmission image of the item G while transporting the item G using the transport unit 5, and performs inspections of the item G (for example, inspection of the number of items stored, inspection of foreign matter contamination, inspection of missing items, inspection of cracks and chips, etc.) based on the X-ray transmission image. The transport unit 5 has an input section 20 arranged upstream in the transport direction A and an output section 30 arranged downstream in the transport direction A. The item G before inspection is transported into the inspection room 4 by the input section 20. The item G after inspection is transported out of the inspection room 4 by the output section 30. The item G determined to be defective by the X-ray inspection device 1 is sorted out of the production line by a sorting device (not shown) arranged downstream of the output section 30. The item G determined to be non-defective by the X-ray inspection device 1 passes through the sorting device as is.

[0021] The X-ray irradiator 6 irradiates X-rays (electromagnetic waves) onto the article G transported by the transport unit 5. The X-ray irradiator 6 includes, for example, an X-ray tube that emits X-rays and a collimator that spreads the X-rays emitted from the X-ray tube in a fan shape within a plane perpendicular to the transport direction A. The X-ray detector 7 detects the X-rays that have been irradiated by the X-ray irradiator 6 and transmitted through the article G. The X-ray detector 7 is configured as, for example, a line sensor. Specifically, the X-ray detector 7 includes a plurality of photodiodes that are arrayed one-dimensionally along a horizontal direction perpendicular to the transport direction A, and a scintillator that is arranged on the X-ray incident side of each photodiode. In this case, the X-ray detector 7 converts the X-rays incident on the scintillator into light, and the light incident on each photodiode is converted into an electrical signal.

[0022] The display operation unit 8 is provided on the upper part 9a of the housing 9 and faces forward. The display operation unit 8 displays various information (i.e., notifies the operator of the operating status) and accepts input of various conditions. The display operation unit 8 is, for example, a liquid crystal display, and displays an operation screen as a touch panel. In this case, the operator can input various conditions via the display operation unit 8. The display operation unit 8 notifies of various abnormalities in the X-ray inspection device 1. A notification light 11, which also functions as a notification unit, is provided on the upper part 9a of the housing 9.

[0023] The control unit 10 is disposed within the device main body 2. The control unit 10 controls the operation of each part of the X-ray inspection device 1. The control unit 10 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. Signals output from the X-ray detection unit 7 and subjected to A / D conversion are input to the control unit 10. The control unit 10 generates an X-ray transmission image of the item G based on the signal output from the X-ray detection unit 7, and functions as an inspection unit that inspects the item G based on the X-ray transmission image.

[0024] Each of the loading section 20 and the unloading section 30 has known components such as a motor, pulleys, timing belt, drive roller, and driven roller (all not shown). The transport unit 5 has a conveyor belt B installed throughout the loading section 20 and the unloading section 30, and causes the conveyor belt B to run at a predetermined speed. As a result, the conveyor unit 5 transports the article G at that running speed. The movement speed (conveying speed) of the conveyor belt B is adjustable. The article G is transported on the transport surface Ba of the conveyor belt B. The transport surface Ba is generally flat (planar), but may undulate slightly during movement.

[0025] As shown in FIG. 3, the loading section 20 includes a frame 21 that supports the conveyor belt B via a pulley. The unloading section 30 includes a frame 31 that supports the conveyor belt B via a pulley. The frames 21 and 31 are made of a metal such as stainless steel. A small gap is formed between the frames 21 and 31 in the conveying direction A. An X-ray passage area X is formed through this gap, allowing X-rays to pass from the X-ray irradiator 6 to the X-ray detector 7. This gap, i.e., the passage area X, extends along direction D (see FIG. 2). Direction D intersects both the conveying direction A in the conveying unit 5 and the opposing direction (the up-down direction in FIG. 2) in which the X-ray irradiator 6 and the X-ray detector 7 face each other. In this embodiment, the conveying direction A and direction D are horizontal, and the opposing direction between the X-ray irradiator 6 and the X-ray detector 7 is vertical.

[0026] 1 and 3, the inspection unit 15 inspects the article G by irradiating the article G with X-rays while the article G is traveling from the entrance opening 4a to the exit opening 4b. In the inspection unit 15, a shielding box and various shielding mechanisms described below prevent X-rays from leaking to the outside. The article G before inspection is carried into the inspection chamber 4 through the entrance opening 4a. The inspected article G is carried out of the inspection chamber 4 through the exit opening 4b.

[0027] The X-ray inspection apparatus 1 includes shielding units 40 that are provided at least at both the entrance opening 4a and the exit opening 4b and that block X-rays leaking to the outside from the entrance opening 4a and the exit opening 4b. The shielding units 40 will be described in detail below with reference to Fig. 3 and subsequent figures.

[0028] As shown in FIG. 3 , the shielding unit 40 prevents X-rays irradiating the article G from leaking from the entrance opening 4a and the exit opening 4b of the inspection chamber 4. The shielding unit 40 includes an upstream shielding unit 40A and a downstream shielding unit 40B. The shielding unit 40A includes three sets of support shafts 43 and a plurality of shielding plates 50 having the same structure. The shielding unit 40B also includes three sets of support shafts 43 and a plurality of shielding plates 50 having the same structure. The shielding unit 40 includes six sets of support shafts 43 and a plurality of shielding plates 50 having the same configuration overall. However, the shielding unit 40A may include only one set of support shafts 43 and a plurality of shielding plates 50 provided at the entrance opening 4a, and the shielding unit 40B may include only one set of support shafts 43 and a plurality of shielding plates 50 provided at the exit opening 4b.

[0029] The shielding unit 40A includes a support shaft 43 that is arranged horizontally near the upper end of the entrance opening 4a, and a plurality of metallic shielding plates 50 that are swingably suspended from the support shaft 43 and aligned in direction D along the support shaft 43. The same members are used for the plurality of shielding plates 50.

[0030] 4, the support shaft 43 extends in a horizontal direction (direction D) perpendicular to the conveying direction A. The support shaft 43 is inserted into elongated holes 47 formed in a pair of support plates 41 spaced apart in direction D, and is supported by the support plates 41. The elongated holes 47 extend in the vertical direction, so that the installation height of the support shaft 43 can also be finely adjusted.

[0031] Each shielding plate 50 is made of, for example, a plate-like member capable of blocking X-rays. Each shielding plate 50 is, for example, a stainless steel plate having a thickness of about 1 mm to several mm. The width of the shielding plate 50 in direction D (the horizontal direction perpendicular to the conveying direction A) can be set appropriately. The end faces of adjacent shielding plates 50 in the width direction may be in contact with each other without overlapping, or the end faces in the width direction may be slightly overlapped. A plurality of shielding plates 50 lined up in the width direction form an X-ray shielding curtain. Each shielding plate 50 is not deformable (or flexible).

[0032] As shown in FIG. 6(a), the base end 51 of each shielding plate 50 is supported by a support shaft 43. The support shaft 43 is inserted into the cylindrical portion of the base end 51, and the base end 51 is rotatable relative to the support shaft 43 (however, further rotation rearward is restricted by a rotation restricting rod 46, which will be described later). That is, in this embodiment, no elastic member such as a coil spring or torsion spring is provided between the base end 51 and the support shaft 43. As shown in FIG. 6(b), the shielding plate 50 easily swings (lifts up and rotates counterclockwise in the figure) when it comes into contact with an article G being conveyed, and as shown in FIG. 6(c), it returns to its original reference position P under its own weight after the article G has passed.

[0033] The shielding unit 40 shields the entrance opening 4a with a support shaft 43 and multiple shielding plates 50 provided in one set. As shown in FIGS. 6(a) and 6(c), the support shaft 43 is provided near the upper end of the inspection chamber 4, and the multiple shielding plates 50 extend from the support shaft 43 to the conveying surface Ba in a reference position P in which the shielding plates 50 are suspended without contacting the article G, thereby shielding the entrance opening 4a. Each shielding plate 50 includes a base end 51, a tip end 52, an inclined surface portion 54, and an upper bent portion 55 (bent portion 53). As described above, the base end 51 is supported by the support shaft 43. Each shielding plate 50 extends only on one side of the support shaft 43. In other words, the support shaft 43 forms one end of each shielding plate 50, and no components such as a balance weight are present above the support shaft 43 (the side opposite the tip end 52). The upper bent portion 55 and the inclined surface portion 54 are provided between the base end portion 51 and the tip end portion 52 .

[0034] The inclined surface portion 54 forms a predetermined inclination angle θ with respect to the conveying surface Ba (assumed to be a horizontal plane) when the shielding plate 50 is in the reference position P. The inclination angle θ is, for example, smaller than 60 degrees, and more preferably smaller than 50 degrees. The tip portion 52 is further bent with respect to the inclined surface portion 54, forming a small gap between it and the conveying surface Ba.

[0035] In this embodiment, the upper bent portion 55 is disposed at a position higher than the midpoint between the base end portion 51 and the tip end portion 52 (closer to the support shaft 43). When the shielding plate 50 is in the reference position P, the upper bent portion 55 is located (protrudes) upstream in the conveying direction A from the center line C of the support shaft 43 (or from a reference plane Ca, which is a vertical plane including the center line C). In other words, the shielding plate 50 in the reference position P extends upstream from the base end portion 51 located at the support shaft 43, turns back at the upper bent portion 55, and the inclined surface portion 54 extends downstream of the reference plane Ca (crossing the reference plane Ca) and terminates at the tip end portion 52, which is the lower end. The upper bent portion 55 is bent, for example, in an arc shape. The direction (angle) of the plate material before and after the upper bent portion 55 is approximately 90 degrees. The direction (angle) of the plate material before and after the upper bent portion 55 may be any value within a range of 60 degrees to 120 degrees. A curved shape such as the upper bent portion 55 makes cleaning of the shielding plate 50 easier than a shape that is bent at an acute angle.

[0036] The shielding plate 50 of the shielding unit 40 includes a portion that extends at a small angle (in a tilted position) such as the inclined surface portion 54 to ensure good passage of the article G. The inclined surface portion 54 is the portion that comes into contact with the article G. The inclined surface portion 54 comes into sliding contact with the article G while the shielding plate 50 moves to the swing position Px (see Figure 6(b)) to allow the article G to pass through. The counterclockwise swing direction shown in Figure 6(b) is called the positive swing direction. The inclined surface portion 54 forms the input surface for external forces when the shielding plate 50 swings.

[0037] Although the shielding unit 40 can accommodate items G of all shapes and sizes, the upper bent portion 55 is formed at an upper position where it will not come into contact with even items G having the maximum height.

[0038] 4, 5, and 6, the shielding unit 40 is further provided with a rotation restriction rod (rotation restriction portion) 46 that restricts rotation of the shielding plate 50 in a negative swing direction opposite to the positive swing direction. The rotation restriction rod 46 extends in a horizontal direction (direction D) perpendicular to the conveying direction A. The rotation restriction rod 46 is inserted into elongated holes 48 formed in a pair of support plates 41 spaced apart in direction D, and is supported by the support plates 41. The elongated holes 48 extend in the vertical direction, so that the installation height of the rotation restriction rod 46 can also be finely adjusted. The rotation restriction rod 46 is positioned, for example, at a position slightly higher than the support shaft 43.

[0039] When the shielding plate 50 is in the reference position P, the rotation restricting rod 46 comes into contact with a position slightly above the upper bent portion 55 (the flat portion between the base end portion 51 and the upper bent portion 55) and restricts the rotation of the shielding plate 50 in the negative swing direction. When the shielding plate 50 is in the reference position P, the rotation restricting rod 46 acts on the shielding plate 50 so as to push the shielding plate 50 up toward the conveying direction A, i.e., so as to swing the shielding plate 50 in the positive swing direction. Specifically, if the rotation restricting rod 46 were not present, the shielding plate 50 would attempt to rotate further in the negative swing direction from the reference position P, but the rotation restricting rod 46 comes into contact with the flat portion and presses against the flat portion.

[0040] As shown in Fig. 6(a), the multiple shielding units 40 having the above configuration maintain the reference position P until an article G arrives. When an article G arrives, as shown in Fig. 6(b), an appropriate number of shielding plates 50 in the width direction come into contact with the article G (determined by the position, shape, and size of the article G), and the shielding plates 50 swing in the positive swing direction. At this time, the resistance applied to the article G is small, and good passage is achieved.

[0041] 5, even when the shielding plates 50 provided in six stages are swung to their maximum positions in the conveying direction A, they do not interfere with (contact with) the adjacently arranged support shafts 43, rotation restriction rods 46, and shielding plates 50. In addition, the pair of shielding plates 50 near the center (close to the passing area X) have a swing range that does not overlap with the passing area X so as not to interfere with the passing area X.

[0042] As shown in FIG. 6(c), after the article G has passed, the shielding plate 50 returns to the reference position P. As shown in FIGS. 3 and 5, the upstream shielding unit 40A equipped with three-stage shielding plates 50 prevents leakage of X-rays upstream of the passage area X. Furthermore, the downstream shielding unit 40B equipped with three-stage shielding plates 50 prevents leakage of X-rays downstream of the passage area X. The configuration of the shielding unit 40B is the same as the configuration of the support shaft 43 and the shielding plate 50 described above. In the shielding unit 40B, a pair of support plates 42 is provided instead of the pair of support plates 41. The support plate 42 also has the same support configuration as the support plate 41, including the long holes 47, 48.

[0043] According to the shielding unit 40 of this embodiment, the entrance opening 4a and the exit opening 4b are shielded by the support shaft 43 and a plurality of metallic shielding plates 50, thereby preventing leakage of X-rays. Each of the shielding plates 50 extends only in one direction from the base end 51 and does not protrude to the other side of the support shaft 43. This improves space efficiency on the other side of the support shaft 43 (see FIGS. 3 and 5). In addition, the bent portion 53 makes it possible to adjust the shape and center of gravity of the shielding plates 50. This makes it possible to reduce the recoil that the article G receives from the shielding plates 50, thereby improving the passage of the article G.

[0044] In the X-ray inspection device 1 that irradiates X-rays onto the transported article G, the entrance opening 4a and the exit opening 4b are shielded, preventing X-rays from leaking outward in the transport direction A. This increases the degree of freedom in layout around the shielding unit 40. In addition, the passage of the article G transported by the transport unit 5 is improved, thereby enhancing the operational stability of the X-ray inspection device 1.

[0045] The bent portion 53 includes an upper bent portion 55 positioned higher than the midpoint between the base end 51 and the tip end 52. This ensures the length of the extension below the upper bent portion 55. Articles G of various sizes (heights) can be passed through the bent portion 53. Furthermore, while maintaining a constant inclination angle θ (see FIG. 6(a)), the distance from the support shaft 43 to the tip end 52 can be shortened, thereby reducing the turning radius of each shielding plate 50. This allows for a higher installation density of the shielding units 40 in a limited section (even a narrow section) of the conveying direction A. For example, if the shielding plates 50 do not swing to the swing position Px shown in FIG. 5, the shielding plates 50 can be arranged closer to each other in the conveying direction A, allowing seven or eight shielding plates 50 to be placed in the same inspection chamber 4. The height of the upper bent portion 55 also raises the center of gravity of the shielding plates 50, improving passage.

[0046] In the reference position P in which the shielding plate 50 is suspended without contacting the article G, the upper bent portion 55 is located (protrudes) upstream of the center line C of the support shaft 43 in the conveying direction A. This makes it easier to reduce the turning radius as described above. It also makes it easier to adjust the center of gravity position to suppress recoil.

[0047] The shielding unit 40 further includes a rotation restriction rod 46 that restricts the rotation of the shielding plate 50. This makes it possible to restrict unnecessary movement of the shielding plate 50 (for example, swinging after an article G has passed through, etc.).

[0048] The rotation restriction rod 46 acts on the shielding plate 50 to push up the shielding plate 50 in the conveying direction A when the shielding plate 50 is in the reference position P in which the shielding plate 50 is suspended without contacting the article G. As a result, the shielding plate 50 is pushed up from the beginning by the rotation restriction rod 46, which further improves the passage of the article G.

[0049] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the upper bent portion 55 (bent portion 53) does not have to be located upstream of the reference plane Ca. For example, the shielding plate 50A shown in Figures 7(a) to 7(c) may be applied. In this case, the upper bent portion 55 is located on or near the center line C of the support shaft 43 (or the reference plane Ca, which is a vertical plane including the center line C) when the shielding plate 50A is in the reference position P. A shielding unit 40 including the shielding plate 50A also achieves the same effects as the above embodiments.

[0050] Also, the rotation restricting rod 46 may be omitted. For example, as in the case of a shielding plate 50A shown in Figures 7(a) to 7(c), an elastic member (not shown) such as a coil spring or a torsion spring may be provided between the base end portion 51 and the support shaft 43.

[0051] The shielding plate 50 may include a plurality of bent portions 53. At least one of the bent portions 53 may be disposed at a position lower than the intermediate position between the base end portion 51 and the tip end portion 52.

[0052] The center of gravity of the shielding plate 50 may be adjusted and the rotation restricting portion may be omitted by devising the position and shape of the bent portion 53. The shielding plate 50 may swing in the negative swing direction in the reference posture.

[0053] The shielding unit 40 may be applied to an apparatus of a type in which the shielding unit 40 is not used together with the transport unit 5, and the article G is inserted into the inspection chamber 4 manually by an operator, for example. [Explanation of symbols]

[0054] 1...X-ray inspection device, 4...inspection room (inspection area), 4a...entrance opening (opening), 4b...exit opening (opening), 5...transport unit (transport section), 6...X-ray irradiation section, 7...X-ray detection section, 20...carry-in section, 30...carry-out section, 40...shielding unit, 43...support shaft, 50...shielding plate, 51...base end, 52...tip end, 53...bending section, 55...upper bending section, 46...rotation control rod (rotation control section), A...transport direction, C...center line, Ca...reference plane, G...item, P...reference position, Px...swinging position.

Claims

1. A shielding unit that prevents X-rays irradiated onto an article from leaking through an opening in the inspection area, a support shaft disposed horizontally near the upper end of the opening; the opening is shielded by a plurality of metallic shielding plates, each of which has a base end supported by the support shaft and is swingably suspended from the support shaft and arranged along the support shaft; A shielding unit, wherein each of the shielding plates extends in only one direction from the base end and has a bent portion between the base end and the tip end.

2. a conveying unit that conveys the article; an X-ray irradiation unit that irradiates the object conveyed by the conveying unit with X-rays; an X-ray detection unit that detects the X-rays that have passed through the article; An X-ray inspection apparatus comprising: the shielding unit according to claim 1.

3. The X-ray inspection apparatus according to claim 2 , wherein the bent portion includes an upper bent portion that is positioned higher than an intermediate position between the base end portion and the tip end portion.

4. The X-ray inspection apparatus according to claim 3 , wherein the upper bent portion is located upstream of a center line of the support shaft in the conveying direction in a reference posture in which the shielding plate is suspended without contacting the object.

5. 5. The X-ray inspection apparatus according to claim 2, wherein the shielding unit further comprises a rotation restricting portion that restricts rotation of the shielding plate.

6. The X-ray inspection apparatus according to claim 5 , wherein the rotation restricting portion acts on the shielding plate so as to push up the shielding plate in the conveying direction when the shielding plate is in a reference position where the shielding plate is suspended without contacting the object.

Images