Screw Looseness Detection Device, Fastening Component, and Screw Looseness Detection Method

Abstract

More easily detect loosening of the screw. 【Solution means】 In the fastening component, among the plurality of leaf spring portions of the washer, the leaf spring portion that is in contact with the portion of the back surface of the screw where there is no depression is pushed downward in the direction of pointing to the substrate by the back surface of the screw, and is electrically connected to any one of the plurality of conductive patterns. When one or more of the plurality of leaf spring portions are electrically connected to the plurality of conductive patterns, the plurality of conductive patterns are electrically connected to each other via one or more leaf spring portions.

Description

Technical Field

[0001] The present disclosure relates to a screw loosening detection device, a fastening component, and a screw loosening detection method, and particularly to a screw loosening detection device, a fastening component, and a screw loosening detection method for detecting screw loosening.

Background Art

[0002] Generally, when a screw is tightened further or when it can be visually observed that the screw has floated from the washer, a person can determine that the screw is loose. Techniques for detecting screw loosening are known, such as a technique of incorporating an electrical or mechanical switch into a washer or monitoring the tightening strength of a screw using a piezoelectric element or the like so that the screw loosening can be automatically detected.

[0003] Also, in the related technique described in Patent Document 1, a screw having a plurality of protrusions formed on the back surface of the head of the screw and a washer in which portions of the washer that come into contact with the respective protrusions of the screw are electrically insulated are used to monitor the conduction state due to the contact between the protrusions of the screw and the washer. And in the related technique described in Patent Document 1, when the screw rotates relative to the washer, since the state of the washer changes from conduction to non-conduction, the loosening of the screw can be detected.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The related technique requires the use of mechanical components such as switches and piezoelectric elements, or the production of a washer composed of two types of materials having different electrical characteristics.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a technique for more easily detecting loosening of a screw.

Means for Solving the Problems

[0007] A screw loosening detection device according to an aspect of the present disclosure includes a shaft portion having a thread formed on its outer periphery, and a head portion connected to one end of the shaft portion on the back surface. On the back surface of the head portion, there is a screw formed with a portion having a recess and a portion having no recess, and a hole through which the shaft portion of the screw penetrates. A plurality of leaf spring portions formed to rise in a direction pointing from an upper surface facing the back surface of the screw toward the back surface when attached to the screw are provided around the hole. A washer provided around the hole, and a substrate having a screw hole through which the shaft portion of the screw penetrates, and a plurality of conductive patterns are formed around the screw hole on a surface facing the lower surface of the washer when the screw is attached to the screw hole. A fastening component including the above, and monitoring means for monitoring a conduction state between each of the plurality of conductive patterns. Among the plurality of leaf spring portions of the washer, the leaf spring portion in contact with the portion of the back surface of the screw having no recess is pushed down in a direction pointing to the substrate by the back surface of the screw and conducts with any one of the plurality of conductive patterns. When one or more of the plurality of leaf spring portions are conducting with the plurality of conductive patterns, the plurality of conductive patterns are conducted with each other through the one or more leaf spring portions. The monitoring means detects that the conduction state of the plurality of conductive patterns has changed due to rotation of the screw with respect to the washer.

[0008] A fastening component according to one aspect of the present disclosure includes a shaft portion having a thread formed on its outer periphery, and a head portion connected to one end of the shaft portion on the back surface. On the back surface of the head portion, there are formed a threaded portion having a recessed portion and a non-recessed portion, a hole through which the shaft portion of the threaded portion passes, and a plurality of leaf spring portions formed to rise in a direction pointing from an upper surface facing the back surface of the threaded portion to the back surface when attached to the threaded portion, which are provided around the hole. A washer, and a substrate having a threaded hole through which the shaft portion of the threaded portion passes, and a plurality of conductive patterns formed around the threaded hole on a surface facing the lower surface of the washer when the threaded portion is attached to the threaded hole.

[0009] A method for detecting screw loosening according to one aspect of the present disclosure includes a shaft portion having a thread formed on its outer periphery, and a head portion connected to one end of the shaft portion on the back surface. On the back surface of the head portion, there are formed a threaded portion having a recessed portion and a non-recessed portion, a hole through which the shaft portion of the threaded portion passes, and a plurality of leaf spring portions formed to rise in a direction pointing from an upper surface facing the back surface of the threaded portion to the back surface when attached to the threaded portion, which are provided around the hole. A washer, a substrate having a threaded hole through which the shaft portion of the threaded portion passes, and a plurality of conductive patterns formed around the threaded hole on a surface facing the lower surface of the washer when the threaded portion is attached to the threaded hole, and a fastening component including the same, and monitoring means for monitoring the conduction state between each of the plurality of conductive patterns. A method for detecting screw loosening using a screw loosening detection device, wherein, among the plurality of leaf spring portions of the washer, a leaf spring portion in contact with the non-recessed portion of the back surface of the threaded portion is pushed down in a direction pointing to the substrate by the back surface of the threaded portion and conducts with any one of the plurality of conductive patterns. When one or more of the plurality of leaf spring portions are conducting with the plurality of conductive patterns, the plurality of conductive patterns are conducting with each other through the one or more leaf spring portions, and the monitoring means detects that the conduction state of the plurality of conductive patterns has changed due to rotation of the threaded portion with respect to the washer. [[Effect of the Invention]]

[0010] According to one aspect of the present disclosure, loosening of a screw can be detected more easily.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0012] Embodiments of the present disclosure will be described with reference to the drawings.

[0013] 〔Embodiment 1〕 Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 7.

[0014] (Fastening part 10) FIG. 1 is an exploded view of a fastening part 10 according to an embodiment. The fastening part 10 is used to fix an object (here, a printed circuit board) to another object. FIG. 1 shows a screw 11, a washer 12, and a conductive pattern 13 that constitute the fastening part 10. The conductive pattern 13 is formed on a printed circuit board by printing or the like. The screw 11 is attached to the printed circuit board on which a plurality of conductive patterns 13 are formed via the washer 12.

[0015] FIG. 2 shows an example of the screw 11 that constitutes the fastening part 10. As shown in FIG. 2, the screw 11 includes a shaft portion 111 having a thread formed on its outer circumference, and a head portion 112 connected to one end of the shaft portion 111 on the back surface. The above-described printed circuit board has a screw hole S through which the shaft portion 111 of the screw 11 passes, and a plurality of conductive patterns 13 are formed around the screw hole S on the surface facing the lower surface of the washer 12 when the screw 11 is attached to the screw hole S.

[0016] FIG. 3 shows the back surface 113 of the head portion 112 of the screw 11. As shown in FIG. 3, on the back surface 113 of the head portion 112 of the screw 11, a portion with a recess D and a portion without a recess D are formed. In the example shown in FIG. 3, the recess D provided on the back surface 113 of the head portion 112 of the screw 11 has an annular sector shape when viewed in plan. Also, four recesses D are formed on the back surface 113. However, the shape and number of the recesses D are not limited.

[0017] FIG. 4 shows an example of the washer 12 that constitutes the fastening part 10. The washer 12 has a hole H through which the shaft portion 111 of the screw 11 passes, and a plurality of leaf spring portions 121 are provided around the hole H and are formed so as to rise in a direction pointing from the upper surface facing the back surface 113 of the screw 11 to the back surface 113 when attached to the screw 11. As shown in FIG. 4, a hole H penetrating the washer 12 is formed at the center of the upper surface of the washer 12 (the surface that contacts the back surface 113 of the head portion 112 of the screw 11). A plurality of leaf spring portions 121 are formed around the hole H.

[0018] FIG. 4 shows a cross-section of the washer 12 when the washer 12 is cut along line A-A passing through the leaf spring portion 121. The leaf spring portion 121 is formed by making a U-shaped (channel-shaped) cut on the upper surface of the washer 12 and lifting the protrusion formed on the washer 12 from the upper surface of the washer 12. Since the washer 12 is formed of an elastic material, the leaf spring portion 121 has a restoring force.

[0019] FIG. 5 shows a cross-section of the washer 12 when the washer 12 is cut along line B-B not passing through the leaf spring portion 121. As shown in FIG. 5, the portion without the leaf spring portion 121 is flat. Since the tip of the leaf spring portion 121 protrudes upward (in the direction facing the back surface 113 of the head 112 of the screw 11) from the upper surface of the washer 12, when the back surface 113 of the screw 11 contacts the upper surface of the washer 12, the leaf spring portion 121 is pushed down to the same height as the portion without the leaf spring portion 121. When a force is applied from above, the leaf spring portion 121 is once pushed down, but when the force disappears, it returns to a state of standing up obliquely from the upper surface of the washer 12.

[0020] The recess D provided in the screw 11 described above has a depth corresponding to the height of the leaf spring portion 121 measured from the upper surface of the washer 12 when the leaf spring portion 121 of the washer 12 stands up obliquely from the upper surface. Therefore, when the back surface 113 of the screw 11 contacts the upper surface of the washer 12, the leaf spring portion 121 is pushed down to the same height as the portion without the leaf spring portion 121, but when the leaf spring portion 121 fits (fits into) the recess D of the back surface 113 of the screw 11, the leaf spring portion 121 remains in a state of standing up obliquely from the upper surface of the washer 12. When the leaf spring portion 121 is electrically connected between the plurality of conductive patterns 13 (the first contacted portion 131 and the second contacted portion 132), the plurality of conductive patterns 13 are electrically connected to each other through the leaf spring portion 121.

[0021] Figure 6 shows an example of a plurality of conductive patterns 13 that make up the fastening component 10. In Figure 6, the washer 12 (Figure 4) on top of the conductive pattern 13 is shown in perspective. As shown in Figure 6, the plurality of conductive patterns 13 are composed of a first contacted portion 131 and a second contacted portion 132.

[0022] The first contacted portion 131 has an annular shape corresponding to the size of the washer 12. When the shaft portion 111 of the screw 11 (Figure 2) passes through the hole H of the washer 12, the first contacted portion 131 contacts at least the peripheral edge of the washer 12.

[0023] A plurality of second contacted portions 132 are provided on the conductive pattern 13. Each second contacted portion 132 has a spot shape corresponding to the size of the leaf spring portion 121 of the washer 12. When the shaft portion 111 of the screw 11 passes through the hole H of the washer 12, the plurality of second contacted portions surround the hole H of the washer 12.

[0024] Both the first contacted portion 131 and the second contacted portion 132 that make up the conductive pattern 13 have conductivity. Therefore, when both the first contacted portion 131 and the second contacted portion 132 are in contact with the washer 12 or its leaf spring portion 121, the first contacted portion 131 and the second contacted portion 132 are electrically connected.

[0025] Figure 7 shows a cross-section of the fastening component 10 when the fastening component 10 is cut along the C-C line shown in Figure 6. However, in Figure 7, the screw 11 that makes up the fastening component 10 is omitted. Figure 7 shows the case where the leaf spring portion 121 of the washer 12 is in contact with only the first contacted portion 131. In this case, the first contacted portion 131 and the second contacted portion 132 are not electrically connected. Note that Figure 1 shows the case where the leaf spring portion 121 of the washer 12 is in contact with both the first contacted portion 131 and the second contacted portion 132. In this case, the first contacted portion 131 and the second contacted portion 132 are electrically connected.

[0026] When the screw 11 loosens, the depression D on the back surface 113 of the screw 11 moves relative to the leaf spring portion 121 of the washer 12. As a result, the leaf spring portion 121 of the washer 12 changes from a state where it is not depressed / a depressed state to a state where it is not depressed / a depressed state.

[0027] As a result, the first contacted portion 131 and the second contacted portion 132 change from a conductive state / a non-conductive state to a non-conductive state / a conductive state.

[0028] Note that the monitoring unit 20 (Fig. 8) described in the following Embodiment 2 monitors the conduction state (whether it is conductive or non-conductive) between the first contacted portion 131 and the second contacted portion 132. By detecting a change in the conduction state between the first contacted portion 131 and the second contacted portion 132, the monitoring unit 20 can indirectly detect loosening of the screw 11.

[0029] (Effect of this embodiment) According to the configuration of this embodiment, the fastening component 10 includes a shaft portion 111 having a thread formed on its outer circumference, and a head portion 112 connected to one end of the shaft portion 111 on the back surface. On the back surface 113 of the head portion 112, there is a screw 11 formed with a portion having a depression D and a portion without a depression D, and a hole H through which the shaft portion 111 of the screw 11 penetrates. A plurality of leaf spring portions 121 are formed so as to rise in a direction pointing from the upper surface facing the back surface 113 of the screw 11 to the back surface 113 when attached to the screw 11, and are provided around the hole H. There is a washer 12, and a substrate having a screw hole through which the shaft portion 111 of the screw 11 penetrates, and a plurality of conductive patterns 13 are formed around the screw hole on the surface facing the lower surface of the washer 12 when the screw 11 is attached to the screw hole. In the fastening component 10, among the plurality of leaf spring portions 121 of the washer 12, the leaf spring portion 121 in contact with the portion of the back surface 113 of the screw 11 without the depression D is pushed down by the back surface 113 of the screw 11 in the direction pointing to the substrate, and conducts with any one of the plurality of conductive patterns 13. When one or more of the plurality of leaf spring portions 121 are conducting with the plurality of conductive patterns 13, the plurality of conductive patterns 13 conduct with each other through one or more leaf spring portions 121.

[0030] When the screw 11 loosens, the depression D on the back surface 113 of the screw 11 moves relative to the leaf spring portion 121 of the washer 12. Therefore, the state where the leaf spring portion 121 of the washer 12 is pushed down / not pushed down changes to the state where the leaf spring portion 121 of the washer 12 is not pushed down / pushed down.

[0031] As a result, the state where the first contacted portion 131 and the second contacted portion 132 are conducting / non-conducting changes to the state where the first contacted portion 131 and the second contacted portion 132 are non-conducting / conducting. By detecting such a change in the conduction state, the loosening of the screw 11 can be easily detected.

[0032] 〔Embodiment 2〕 Referring to FIGS. 8 to 10, Embodiment 2 of the present disclosure will be described. In Embodiment 2, an example of the configuration of a screw loosening detection device 1 that includes a monitoring unit 20 connected to the conductive pattern 13 of the fastening component 10 and detects loosening of a screw 11 attached to a printed circuit board 30 will be described.

[0033] (Screw loosening detection device 1) FIG. 8 is a diagram showing an example of a screw loosening detection device 1 according to an embodiment. As shown in FIG. 8, the screw loosening detection device 1 is composed of a conductive pattern 13 of a fastening component 10 and a printed circuit board 30 on which a processing circuit is formed. Each of the processing circuit and the second contacted portion 132 of the conductive pattern 13 is connected by a conducting wire. Hereinafter, the processing circuit will be referred to as a monitoring unit 20.

[0034] The monitoring unit 20 monitors the conduction state between the first contacted portion 131 and the second contacted portion 132 of the conductive pattern 13. The monitoring unit 20 is an example of a monitoring means.

[0035] As described in Embodiment 1, in the fastening component 10 (FIG. 1), when the leaf spring portion 121 (FIG. 4) of the washer 12 contacts a portion of the back surface 113 (FIG. 2) of the screw 11 where there is no depression D (FIG. 2), the leaf spring portion 121 is pushed down by the back surface 113 of the screw 11 and contacts both the first contacted portion 131 and the second contacted portion 132 of the conductive pattern 13. On the other hand, when the leaf spring portion 121 of the washer 12 fits into the depression D on the back surface 113 of the screw 11, the leaf spring portion 121 is not pushed down by the back surface 113 of the screw 11 and contacts only the first contacted portion 131 of the conductive pattern 13.

[0036] The monitoring unit 20 according to an embodiment detects that the conduction state between the first contacted portion 131 and the second contacted portion 132 has changed due to the rotation of the screw 11 with respect to the washer 12 and the change in the way the leaf spring portion 121 of the washer 12 contacts the back surface 113 of the screw 11.

[0037] Here, "the state of conduction changes" means "changing from a conductive state to a non-conductive state" or vice versa.

[0038] (When the screw 11 is not loose) FIG. 9 shows an example of the relative positional relationship among the depression D of the screw 11, the leaf spring portion 121 of the washer 12, and the second contact portion 132 of the conductive pattern 13 when the screw 11 is not loose. In the example shown in FIG. 9, the leaf spring portion 121 of the washer 12 is fitted (contained) within the depression D of the screw 11. At this time, as described in the first embodiment, the leaf spring portion 121 is not pushed down by the back surface 113 of the screw 11 and contacts only the first contact portion 131 (not shown) of the conductive pattern 13.

[0039] At this time, the monitoring unit 20 detects that the first contact portion 131 and the second contact portion 132 are in a non-conductive state.

[0040] (When the screw 11 is loose) FIG. 10 shows an example of the relative positional relationship among the depression D of the screw 11, the leaf spring portion 121 of the washer 12, and the second contact portion 132 of the conductive pattern 13 when the screw 11 is loose. In the example shown in FIG. 10, the leaf spring portion 121 of the washer 12 is about to come out of the depression D of the screw 11. At this time, since the leaf spring portion 121 is pushed down by the back surface 113 of the screw 11, it contacts both the first contact portion 131 (not shown) and the second contact portion 132 of the conductive pattern 13.

[0041] At this time, the monitoring unit 20 detects that the first contact portion 131 and the second contact portion 132 are in a conductive state.

[0042] In this way, the conduction state between the first contact portion 131 and the second contact portion 132 changes between when the screw 11 is not loose (FIG. 9) and when the screw 11 is loose (FIG. 10). The monitoring unit 20 monitors this conduction state and can indirectly detect that the screw 11 has become loose by detecting the change in the conduction state.

[0043] (Effects of this Embodiment) According to the configuration of this embodiment, the fastening component 10 includes a shaft portion 111 having a thread formed on its outer periphery, and a head portion 112 connected to one end of the shaft portion 111 on the back surface. On the back surface 113 of the head portion 112, there is a screw 11 formed with a portion having a depression D and a portion without a depression D, and a hole H through which the shaft portion 111 of the screw 11 passes. A plurality of leaf spring portions 121 are formed so as to rise in a direction pointing from the upper surface facing the back surface 113 of the screw 11 to the back surface 113 when attached to the screw 11, and are provided around the hole H with a washer 12. The screw hole through which the shaft portion 111 of the screw 11 passes, and a substrate on which a plurality of conductive patterns 13 are formed around the screw hole on a surface facing the lower surface of the washer 12 when the screw 11 is attached to the screw hole. In the fastening component 10, among the plurality of leaf spring portions 121 of the washer 12, the leaf spring portion 121 in contact with the portion of the back surface 113 of the screw 11 without the depression D is pushed down in the direction pointing to the substrate by the back surface 113 of the screw 11 and conducts with any one of the plurality of conductive patterns 13. When one or more of the plurality of leaf spring portions 121 are conducting with the plurality of conductive patterns 13, the plurality of conductive patterns 13 conduct with each other through one or more leaf spring portions 121.

[0044] The screw loosening detection device 1 includes a fastening component 10 and a monitoring unit 20. The monitoring unit 20 monitors the conduction state between each of the plurality of conductive patterns 13. The monitoring unit 20 detects that the conduction state of the plurality of conductive patterns 13 has changed due to the rotation of the screw 11 with respect to the washer 12.

[0045] Since the monitoring unit 20 of the screw loosening detection device 1 detects such a change in the conduction state, the loosening of the screw 11 can be easily detected.

[0046] (Supplementary Note) Some or all of the above embodiments may be described as follows in the supplementary note, but are not limited thereto.

[0047] (Supplementary Note 1) A screw having a shaft portion with a thread formed on its outer circumference, and a head portion connected to one end of the shaft portion on the back surface, wherein on the back surface of the head portion, a screw is formed with a portion having a depression and a portion without a depression, a washer provided with a plurality of leaf spring portions formed so as to rise in a direction pointing from the upper surface facing the back surface of the screw when the screw is attached to the screw, around the hole through which the shaft portion of the screw passes, a substrate having a screw hole through which the shaft portion of the screw passes, and a plurality of conductive patterns formed around the screw hole on a surface facing the lower surface of the washer when the screw is attached to the screw hole, a fastening component comprising: monitoring means for monitoring the conduction state between each of the plurality of conductive patterns; comprising Among the plurality of leaf spring portions of the washer, the leaf spring portion in contact with the portion of the back surface of the screw without the depression is pushed down in the direction pointing to the substrate by the back surface of the screw, and conducts with any one of the plurality of conductive patterns, When one or more of the plurality of leaf spring portions are conducting with the plurality of conductive patterns, the plurality of conductive patterns are conducting with each other through the one or more leaf spring portions, The monitoring means detects that the conduction state of the plurality of conductive patterns has changed due to the rotation of the screw with respect to the washer a screw loosening detection device.

[0048] (Supplementary Note 2) The depression provided in the screw has a depth corresponding to the height of the leaf spring portion measured from the surface when the leaf spring portion of the washer rises obliquely from the surface. The screw loosening detection device according to Supplementary Note 1, characterized in that.

[0049] (Supplementary Note 3) The depression provided in the screw has an annular sector shape. The screw loosening detection device according to Supplementary Note 1, characterized in that.

[0050] (Appendix 4) The leaf spring portion provided on the washer is formed by making a cut in the surface of the washer and lifting a protrusion formed on the washer from the surface of the washer. The screw loosening detection device according to Appendix 1, characterized in that.

[0051] (Appendix 5) The plurality of conductive patterns are formed on the surface of a printed circuit board fixed by the screw, and the monitoring means is disposed on the printed circuit board and is electrically connected to the plurality of conductive patterns. The screw loosening detection device according to Appendix 1, characterized in that.

[0052] (Appendix 6) The plurality of conductive patterns include a first contacted portion having an annular shape corresponding to the size of the washer, and when the shaft portion of the screw penetrates the hole of the washer, the first contacted portion contacts at least the peripheral edge of the washer. The screw loosening detection device according to Appendix 1, characterized in that.

[0053] (Appendix 7) The plurality of conductive patterns include a plurality of second contacted portions having a speckled shape corresponding to the size of the leaf spring portion of the washer, and the plurality of second contacted portions surround the screw hole of the substrate. The screw loosening detection device according to Appendix 1, characterized in that.

[0054] (Appendix 8) The monitoring means holds information indicating the conduction state of the plurality of conductive patterns when the screw is not loose, and detects loosening of the screw when the conduction state of the plurality of conductive patterns changes. The screw loosening detection device according to Appendix 1, characterized in that.

[0055] (Appendix 9) A fastening component provided with the screw loosening detection device according to any one of Supplementary Notes 1 to 8, comprising a shaft portion having a thread formed on its outer periphery, and a head portion connected to one end of the shaft portion on the back surface, and the screw having a portion with a recess and a portion without a recess formed on the back surface of the head portion, a washer provided with a plurality of leaf spring portions formed around a hole through which the shaft portion of the screw passes and rising in a direction pointing from the upper surface facing the back surface of the screw when attached to the screw toward the back surface, a substrate having a screw hole through which the shaft portion of the screw passes and having a plurality of conductive patterns formed around the screw hole on a surface facing the lower surface of the washer when the screw is attached to the screw hole, and a fastening component comprising the above.

[0056] (Supplementary Note 10) comprising a shaft portion having a thread formed on its outer periphery, and a head portion connected to one end of the shaft portion on the back surface, and the screw having a portion with a recess and a portion without a recess formed on the back surface of the head portion, a washer provided with a plurality of leaf spring portions formed around a hole through which the shaft portion of the screw passes and rising in a direction pointing from the upper surface facing the back surface of the screw when attached to the screw toward the back surface, a substrate having a screw hole through which the shaft portion of the screw passes and having a plurality of conductive patterns formed around the screw hole on a surface facing the lower surface of the washer when the screw is attached to the screw hole, and a fastening component comprising the above, monitoring means for monitoring the conduction state between each of the plurality of conductive patterns, and a screw loosening detection method using a screw loosening detection device comprising the above, Among the plurality of leaf spring portions of the washer, the leaf spring portion in contact with the portion without the recess on the back surface of the screw is pushed down in a direction pointing to the substrate by the back surface of the screw and conducts with any one of the plurality of conductive patterns, When one or more of the plurality of leaf spring portions are electrically connected to the plurality of conductive patterns, the plurality of conductive patterns are electrically connected to each other through the one or more leaf spring portions. The monitoring means detects that the conduction state of the plurality of conductive patterns has changed due to the rotation of the screw with respect to the washer. Screw loosening detection method.

[0057] In addition, part or all of the configurations described in Appendices 2 to 8, which are subordinate to Appendix 1 described above, may be subordinate to Appendix 10 in the same subordinate relationship as Appendices 2 to 8. Furthermore, within the scope not departing from the above-described embodiments, part or all of the configurations described as appendices can similarly be made subordinate to various hardware, software, various recording means for recording software, or systems.

[0058] The present disclosure has been described with reference to several embodiments. However, the present disclosure is not limited to the above embodiments. Each embodiment can be combined with other embodiments as appropriate. Also, various changes that can be understood by those skilled in the art can be made to the configurations and details of the above embodiments within the scope of the present disclosure.

Industrial Applicability

[0059] The present disclosure can be used, for example, to detect loosening of a screw attached to a printed circuit board.

Explanation of Signs

[0060] 1 Screw loosening detection device 10 Fastening parts 11 Screw 111 Shaft part 112 Head 113 Rear surface 12 Washer 121 Leaf spring part 13 Conductive pattern 131 First contacted part 132 Second contacted part 20 Monitoring section 30 Printed circuit board D Depression H Hole S Screw hole

Claims

1. A fastening component comprising a shaft portion having a thread formed on its outer periphery, and a head portion connected to one end of the shaft portion on the back surface, wherein on the back surface of the head portion, there is a screw having a portion with a recess and a portion without a recess, a washer provided with a hole through which the shaft portion of the screw passes, and a plurality of leaf spring portions formed so as to rise in a direction pointing from the upper surface facing the back surface of the screw toward the back surface when the screw is attached to the washer, around the hole, a substrate having a screw hole through which the shaft portion of the screw passes, and a plurality of conductive patterns formed around the screw hole on a surface facing the lower surface of the washer when the screw is attached to the screw hole, and a monitoring means for monitoring the conduction state between each of the plurality of conductive patterns. The fastening component is provided with Among the plurality of leaf spring portions of the washer, the leaf spring portion in contact with the portion of the back surface of the screw without the recess is pushed downward in the direction pointing to the substrate by the back surface of the screw, and conducts with any one of the plurality of conductive patterns, When one or more of the plurality of leaf spring portions are conducting with the plurality of conductive patterns, the plurality of conductive patterns are conducting with each other via the one or more leaf spring portions, The monitoring means detects that the conduction state of the plurality of conductive patterns has changed due to the rotation of the screw with respect to the washer. A screw loosening detection device.

2. The recess provided in the screw has a depth corresponding to the height of the leaf spring portion measured from the surface when the leaf spring portion of the washer rises obliquely from the surface. The screw loosening detection device according to claim 1, characterized in that

3. The recess provided in the screw has an annular sector shape. The screw loosening detection device according to claim 1, characterized in that

4. The leaf spring portion provided on the washer is formed by making a cut in the lower surface of the washer and lifting a protrusion formed on the washer from the lower surface of the washer. The screw loosening detection device according to claim 1, characterized in that

5. The plurality of conductive patterns are formed on the surface of the substrate fixed by the screw, and the monitoring means is arranged on the substrate and is electrically connected to the plurality of conductive patterns. The screw loosening detection device according to claim 1, characterized in that

6. ​ The plurality of conductive patterns include a first contacted portion having an annular shape corresponding to the size of the washer, and when the screw is attached to the screw hole of the substrate through the hole of the washer, the first contacted portion contacts the peripheral edge of the lower surface of the washer. The screw loosening detection device according to claim 1, characterized in that.

7. The plurality of conductive patterns include a plurality of second contacted portions having a spot shape corresponding to the size of the leaf spring portion of the washer, and the plurality of second contacted portions surround the screw hole of the substrate. The screw loosening detection device according to claim 1, characterized in that.

8. The monitoring means holds information indicating the conduction state of the plurality of conductive patterns when the screw is not loose, and detects the loosening of the screw when the conduction state of the plurality of conductive patterns changes. The screw loosening detection device according to claim 1, characterized in that.

9. A fastening component provided with the screw loosening detection device according to any one of claims 1 to 8, comprising a shaft portion having a thread formed on the outer periphery, and a head portion connected to one end of the shaft portion on the back surface, wherein on the back surface of the head portion, there is a screw in which a portion with a recess and a portion without a recess are formed, a washer provided with a plurality of leaf spring portions formed so as to rise in a direction pointing from the upper surface facing the back surface of the screw to the back surface when the screw is attached, around the hole through which the shaft portion of the screw passes, a substrate having a screw hole through which the shaft portion of the screw passes, and a plurality of conductive patterns formed around the screw hole on the surface facing the lower surface of the washer when the screw is attached to the screw hole, A fastening component comprising.

10. Comprising a shaft portion having a thread formed on the outer periphery, and a head portion connected to one end of the shaft portion on the back surface, wherein on the back surface of the head portion, there is a screw in which a portion with a recess and a portion without a recess are formed, a washer provided with a plurality of leaf spring portions formed so as to rise in a direction pointing from the upper surface facing the back surface of the screw to the back surface when the screw is attached, around the hole through which the shaft portion of the screw passes, a substrate having a screw hole through which the shaft portion of the screw passes, and a plurality of conductive patterns formed around the screw hole on the surface facing the lower surface of the washer when the screw is attached to the screw hole, a fastening component provided therewith; monitoring means for monitoring the conduction state between each of the plurality of conductive patterns; A screw loosening detection method using a screw loosening detection device provided therewith, Among the plurality of leaf spring portions of the washer, the leaf spring portion in contact with the portion of the back surface of the screw where there is no depression is pushed down by the back surface of the screw in the direction of pointing to the substrate, and conducts with any one of the plurality of conductive patterns; When one or more leaf spring portions among the plurality of leaf spring portions are conducting with the plurality of conductive patterns, the plurality of conductive patterns are conducting with each other via the one or more leaf spring portions; The monitoring means detects that the conduction state of the plurality of conductive patterns has changed due to the rotation of the screw with respect to the washer; Screw loosening detection method.

Images