Screw looseness detection device, fastening component and screw looseness detection method

Abstract

To more simply detect looseness of a screw.SOLUTION: In a fastening component, of a plurality of leaf spring parts of a washer, leaf spring parts that are in contact with a portion of a back surface of a screw that does not have a recess are pressed down by the back surface of the screw in a direction toward a substrate, and is electrically connected to one of a plurality of conductive patterns. When one or more of the plurality of leaf spring parts are electrically connected to the plurality of conductive patterns, the plurality of conductive patterns is electrically connected to each other via one or more leaf spring parts.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a screw loosening detection device, a fastener, and a screw loosening detection method, and more particularly to a screw loosening detection device, a fastener, and a screw loosening detection method for detecting looseness of a screw. [Background technology]

[0002] Generally, a person can determine if a screw is loose when they tighten it further or when they can see that the screw has come loose from the washer. Methods that can automatically detect loose screws include incorporating an electrical or mechanical switch into the washer, or using a piezoelectric element or the like to monitor the tightening strength of the screw to detect loose screws.

[0003] Furthermore, the related technology described in Patent Document 1 uses a screw with multiple protrusions formed on the back surface of the screw head and a washer in which the parts of the washer that come into contact with the protrusions on the screw are electrically insulated from each other, and monitors the state of conductivity due to contact between the protrusions on the screw and the washer. In the related technology described in Patent Document 1, when the screw rotates relative to the washer, the state of the washer changes from conductive to non-conductive, making it possible to detect loosening of the screw. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 9248352 Summary of the Invention [Problem to be solved by the invention]

[0005] Related techniques involve using mechanical components such as switches or piezoelectric elements, or creating washers made of two materials with different electrical properties.

[0006] The present disclosure has been made in view of the above-mentioned problems, and has an object to provide a technique for more easily detecting loose screws. [Means for solving the problem]

[0007] A screw loosening detection device according to one aspect of the present disclosure includes a screw including a shank having a screw thread formed on its outer periphery and a head connected to one end of the shank at its back surface, the back surface of the head having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, the washer having a plurality of leaf spring portions formed to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the screw is attached to the screw, the washer being provided around the hole; and a substrate having a screw hole through which the shank of the screw passes, the substrate having a surface facing the lower surface of the washer when the screw is attached to the screw hole, the substrate having a plurality of conductive patterns formed around the screw hole. and a monitoring means for monitoring the state of conduction between the component and each of the plurality of conductive patterns, wherein the leaf spring portions of the washer that are in contact with the portion of the back surface of the screw that does not have the recess are pressed down by the back surface of the screw in a direction toward the board, thereby establishing conduction between the leaf spring portions and any of the plurality of conductive patterns, and 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, and the monitoring means detects that the state of conduction of the plurality of conductive patterns has changed due to the rotation of the screw relative to the washer.

[0008] A fastening component according to one aspect of the present disclosure comprises: a screw having a shank with threads formed on its outer periphery, and a head connected to one end of the shank at its back surface, the back surface of the head having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, the washer having a plurality of leaf spring portions formed around the hole and extending from an upper surface facing the back surface of the screw when the screw is attached to the screw in a direction toward the back surface; and a substrate having a threaded hole through which the shank of the screw passes, the substrate having a surface facing the lower surface of the washer when the screw is attached to the screw hole, the substrate having a plurality of conductive patterns formed around the screw hole.

[0009] A method for detecting loose screws according to one aspect of the present disclosure includes a fastening component including: a screw having a shank with threads formed on its outer periphery and a head connected to one end of the shank at its back surface, the back surface of the head having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, the washer having a plurality of leaf spring portions formed around the hole so as to rise from an upper surface facing the back surface of the screw in a direction pointing towards the back surface when the screw is attached to the screw; and a substrate having a screw hole through which the shank of the screw passes, the substrate having a surface facing a lower surface of the washer when the screw is attached to the screw hole, the substrate having a plurality of conductive patterns formed around the screw hole; and a monitoring means for monitoring the state of conduction between each of the leaf springs, wherein of the plurality of leaf spring portions of the washer, those leaf spring portions that are in contact with the portion of the back surface of the screw that does not have the recess are pressed down by the back surface of the screw in a direction toward the board, and become conductive with any of the plurality of conductive patterns, and when one or more of the plurality of leaf spring portions are conductive with the plurality of conductive patterns, the plurality of conductive patterns become conductive with each other via the one or more leaf spring portions, and the monitoring means detects that the state of conduction of the plurality of conductive patterns has changed due to the rotation of the screw relative to the washer. [Effects of the Invention]

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

[0011] [Figure 1] FIG. 2 is an exploded view of a fastening component according to one embodiment. [Figure 2] FIG. 2 is a side view of a screw constituting a fastening component according to one embodiment. [Figure 3] 1 shows the back surface of a head of a screw constituting a fastening component according to one embodiment. [Figure 4] 2A and 2B are a plan view and a cross-sectional view taken along line AA of a washer constituting a fastening component according to one embodiment. [Figure 5] 1A and 1B are a plan view and a BB cross-sectional view of a washer constituting a fastening component according to one embodiment. [Figure 6] 10A and 10B are diagrams illustrating an example of a conductive pattern that configures a fastening component according to an embodiment. [Figure 7] This shows a case where the plate spring portion of the washer is not pressed down and is in contact with both the first contacted portion and the second contacted portion of the conductive pattern. [Figure 8] 1 is a diagram showing an example of a screw loosening detection device according to an embodiment; [Figure 9] 10 shows the positional relationship between the recess of the screw, the leaf spring portion of the washer, and the second contacted portion of the conductive pattern on the printed circuit board when the screw is tightened. [Figure 10] 10 shows the positional relationship between the recess of the screw, the leaf spring portion of the washer, and the second contacted portion of the conductive pattern on the printed circuit board when the screw is loose. DETAILED DESCRIPTION OF THE INVENTION

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

[0013] [Embodiment 1] A first embodiment of the present disclosure will be described with reference to FIGS.

[0014] (Fastening part 10) FIG. 1 is an exploded view of a fastening component 10 according to one embodiment. The fastening component 10 is used to fasten 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 component 10. The conductive pattern 13 is formed on the printed circuit board by printing or the like. The screw 11 is attached via the washer 12 to the printed circuit board on which multiple conductive patterns 13 are formed.

[0015] Fig. 2 shows an example of a screw 11 constituting the fastening component 10. As shown in Fig. 2, the screw 11 has a shank 111 with threads formed on the outer periphery thereof, and a head 112 connected to one end of the shank 111 at the back surface. The printed circuit board described above has a screw hole S through which the shank 111 of the screw 11 passes, and a plurality of conductive patterns 13 are formed around the screw hole S on the surface that faces the underside 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 112 of the screw 11. As shown in FIG. 3, the back surface 113 of the head 112 of the screw 11 has a portion with a recess D and a portion without a recess D. In the example shown in FIG. 3, the recess D provided on the back surface 113 of the head 112 of the screw 11 has an annular sector shape when viewed in a plan view. Furthermore, four recesses D are formed on the back surface 113. However, the shape and number of the recesses D are not limited.

[0017] 4 shows an example of a washer 12 constituting the fastening component 10. The washer 12 has a hole H through which the shank 111 of the screw 11 passes, and a plurality of leaf spring portions 121 are provided around the hole H, the leaf spring portions 121 being formed so as to rise from the upper surface facing the back surface 113 of the screw 11 when the washer 12 is attached to the screw 11 in a direction toward the back surface 113. As shown in FIG. 4, a hole H is formed in the center of the upper surface of the washer 12 (the surface that comes into contact with the back surface 113 of the head 112 of the screw 11). A plurality of leaf spring portions 121 are formed around the hole H.

[0018] 4 shows a cross section of washer 12 when washer 12 is cut along line AA passing through leaf spring portion 121. Leaf spring portion 121 is formed by making a U-shaped cut in the upper surface of washer 12 and lifting a protrusion formed on washer 12 from the upper surface of washer 12. Because washer 12 is made of an elastic material, leaf spring portion 121 has a restoring force.

[0019] 5 shows a cross section of washer 12 taken along line BB, which does not pass through leaf spring portion 121. As shown in FIG. 5, the portion where leaf spring portion 121 does not exist is flat. The tip of leaf spring portion 121 protrudes above the top surface of washer 12 (in a direction facing back surface 113 of head 112 of screw 11). Therefore, when back surface 113 of screw 11 comes into contact with the top surface of washer 12, leaf spring portion 121 is pressed down to the same height as the portion where leaf spring portion 121 does not exist. When force is applied from above, leaf spring portion 121 is pressed down once, but when the force is removed, it returns to a state where it stands up diagonally from the top surface of 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 rises obliquely from the upper surface. Therefore, when the back surface 113 of the screw 11 comes into contact with the upper surface of the washer 12, the leaf spring portion 121 is pressed down to the same height as a portion where the leaf spring portion 121 is not present. However, when the leaf spring portion 121 is fitted (settled) in the recess D in the back surface 113 of the screw 11, the leaf spring portion 121 remains in a state rising obliquely from the upper surface of the washer 12. When the leaf spring portion 121 is electrically connected to 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 via the leaf spring portion 121.

[0021] Fig. 6 shows an example of the plurality of conductive patterns 13 that make up the fastening component 10. Fig. 6 shows a perspective view of the washer 12 (Fig. 4) on the conductive patterns 13. As shown in Fig. 6, the plurality of conductive patterns 13 are made up 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, and when the shank 111 of the screw 11 (Figure 2) passes through the hole H of the washer 12, the first contacted portion 131 comes into contact with at least the peripheral portion of the washer 12.

[0023] The conductive pattern 13 is provided with a plurality of second contacted portions 132. Each of the second contacted portions 132 has a spotted shape corresponding to the size of the leaf spring portion 121 of the washer 12, and when the shank 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 part 131 and the second contacted part 132 constituting the conductive pattern 13 are conductive. Therefore, when both the first contacted part 131 and the second contacted part 132 are in contact with the washer 12 or its leaf spring part 121, the first contacted part 131 and the second contacted part 132 are electrically connected.

[0025] FIG. 7 shows a cross section of the fastening component 10 when the fastening component 10 is cut along the line CC shown in FIG. 6. However, in FIG. 7, the screw 11 constituting the fastening component 10 is omitted. FIG. 7 shows a 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 FIG. 1 shows a 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 is loosened, the depression D on the back surface 113 of the screw 11 moves relative to the plate spring portion 121 of the washer 12, so that the plate spring portion 121 of the washer 12 changes from a pressed down / not pressed down state to a not pressed down / pressed down state.

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

[0028] The monitoring unit 20 (FIG. 8) described in the next embodiment 2 monitors the conduction state (conduction or non-conduction) between the first contacted part 131 and the second contacted part 132. The monitoring unit 20 can indirectly detect loosening of the screw 11 by detecting a change in the conduction state between the first contacted part 131 and the second contacted part 132.

[0029] (Effects of this embodiment) According to the configuration of this embodiment, the fastening part 10 comprises a shank 111 having a screw thread formed on its outer periphery, and a head 112 connected to one end of the shank 111 at its back surface. The back surface 113 of the head 112 has a portion with a recess D and a portion without the recess D formed thereon. The fastening part 10 comprises a washer 12 having a hole H through which the shank 111 of the screw 11 passes, and having multiple leaf spring portions 121 formed to rise from the upper surface facing the back surface 113 of the screw 11 in a direction toward the back surface 113, the multiple leaf spring portions 121 being provided around the hole H. The washer 12 also comprises a substrate having a screw hole through which the shank 111 of the screw 11 passes, and having multiple conductive patterns 13 formed around the screw hole on the surface facing the lower surface of the washer 12 when the screw 11 is fitted into the screw hole. In the fastening part 10, of the multiple leaf spring portions 121 of the washer 12, the leaf spring portion 121 that is in contact with the portion of the back surface 113 of the screw 11 that does not have the depression D is pressed down by the back surface 113 of the screw 11 in the direction toward the substrate, and becomes conductive with one of the multiple conductive patterns 13, and when one or more of the multiple leaf spring portions 121 are conductive with the multiple conductive patterns 13, the multiple conductive patterns 13 become conductive with each other via one or more leaf spring portions 121.

[0030] When the screw 11 is loosened, the depression D on the back surface 113 of the screw 11 moves relative to the plate spring portion 121 of the washer 12, so that the plate spring portion 121 of the washer 12 changes from a pressed down / not pressed down state to a not pressed down / pressed down state.

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

[0032] [Embodiment 2] A second embodiment of the present disclosure will be described with reference to Figures 8 to 10. In this second embodiment, an example of the configuration of a screw loosening detection device 1 will be described, which includes a monitoring unit 20 connected to the conductive pattern 13 of the fastening component 10 described in the first embodiment and detects loosening of a screw 11 attached to a printed circuit board 30.

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

[0034] The monitoring unit 20 monitors the state of conduction 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 the first embodiment, in the fastening part 10 (Fig. 1), when the leaf spring portion 121 (Fig. 4) of the washer 12 is in contact with a portion of the back surface 113 (Fig. 2) of the screw 11 where there is no recess D (Fig. 2), the leaf spring portion 121 is pressed down by the back surface 113 of the screw 11 and comes into contact with both the first contacted portion 131 and the second contacted portion 132 of the conductive pattern 13, whereas when the leaf spring portion 121 of the washer 12 is fitted into the recess D of the back surface 113 of the screw 11, the leaf spring portion 121 is not pressed down by the back surface 113 of the screw 11 and comes into contact only with the first contacted portion 131 of the conductive pattern 13.

[0036] In one embodiment, the monitoring unit 20 detects that the state of conduction between the first contacted portion 131 and the second contacted portion 132 has changed due to the screw 11 rotating relative to the washer 12 and the manner in which the contact between the leaf spring portion 121 of the washer 12 and the back surface 113 of the screw 11 has changed.

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

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

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

[0040] (When screw 11 is loose) 10 shows an example of the relative positional relationship between the recess D of the screw 11, the leaf spring portion 121 of the washer 12, and the second contacted 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 off the recess D of the screw 11. At this time, the leaf spring portion 121 is pressed down by the back surface 113 of the screw 11, and comes into contact with both the first contacted portion 131 (not shown) and the second contacted portion 132 of the conductive pattern 13.

[0041] At this time, the monitoring unit 20 detects that the first contacted part 131 and the second contacted part 132 are in an electrically conductive state.

[0042] In this way, the state of conduction between the first contacted part 131 and the second contacted part 132 changes between when the screw 11 is not loosened (FIG. 9) and when the screw 11 is loosened (FIG. 10). The monitoring part 20 monitors this state of conduction and detects the change in the state of conduction, thereby indirectly detecting that the screw 11 has loosened.

[0043] (Effects of this embodiment) According to the configuration of this embodiment, the fastening part 10 comprises a shank 111 having a screw thread formed on its outer periphery, and a head 112 connected to one end of the shank 111 at its back surface. The back surface 113 of the head 112 has a portion with a recess D and a portion without the recess D formed thereon. The fastening part 10 comprises a washer 12 having a hole H through which the shank 111 of the screw 11 passes, and having multiple leaf spring portions 121 formed to rise from the upper surface facing the back surface 113 of the screw 11 in a direction toward the back surface 113, the multiple leaf spring portions 121 being provided around the hole H. The washer 12 also comprises a substrate having a screw hole through which the shank 111 of the screw 11 passes, and having multiple conductive patterns 13 formed around the screw hole on the surface facing the lower surface of the washer 12 when the screw 11 is fitted into the screw hole. In the fastening part 10, of the multiple leaf spring portions 121 of the washer 12, the leaf spring portion 121 that is in contact with the portion of the back surface 113 of the screw 11 that does not have the depression D is pressed down by the back surface 113 of the screw 11 in the direction toward the substrate, and becomes conductive with one of the multiple conductive patterns 13, and when one or more of the multiple leaf spring portions 121 are conductive with the multiple conductive patterns 13, the multiple conductive patterns 13 become conductive with each other via 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 state of conduction between each of the plurality of conductive patterns 13. The monitoring unit 20 detects a change in the state of conduction between the plurality of conductive patterns 13 due to the rotation of the screw 11 relative to the washer 12.

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

[0046] (Addendum) A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0047] (Appendix 1) a screw comprising a shaft portion having a thread formed on its outer periphery and a head portion connected to one end of the shaft portion at its back surface, the back surface of the head portion having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, and a plurality of leaf springs formed to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the washer is attached to the screw, and the leaf springs are provided around the hole; a substrate having a screw hole through which the shank of the screw passes, the substrate having a surface facing the lower surface of the washer when the screw is attached to the screw hole, the surface having a plurality of conductive patterns formed around the screw hole; a fastening component comprising: a monitoring means for monitoring a state of conduction between each of the plurality of conductive patterns; Equipped with Among the plurality of leaf spring portions of the washer, a leaf spring portion in contact with a portion of the back surface of the screw that does not have the recess is pressed down by the back surface of the screw in a direction toward the substrate, 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 the one or more leaf spring portions, The monitoring means detects a change in the state of conduction of the plurality of conductive patterns due to the rotation of the screw relative to the washer. Screw loosening detection device.

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

[0049] (Appendix 3) The recess provided in the screw has an annular sector shape. 2. The screw loosening detection device according to claim 1,

[0050] (Appendix 4) The leaf spring portion provided on the washer is formed by making a notch on the surface of the washer and lifting a protrusion formed on the washer from the surface of the washer. 2. The screw loosening detection device according to claim 1,

[0051] (Appendix 5) The plurality of conductive patterns are formed on a surface of a printed circuit board fixed by the screws, and the monitoring means is disposed on the printed circuit board and electrically connected to the plurality of conductive patterns. 2. The screw loosening detection device according to claim 1,

[0052] (Appendix 6) The plurality of conductive patterns include a first contacted portion having a ring shape corresponding to the size of the washer, and the first contacted portion comes into contact with at least a peripheral portion of the washer when the shank of the screw passes through the hole of the washer. 2. The screw loosening detection device according to claim 1,

[0053] (Appendix 7) The plurality of conductive patterns include a plurality of second contacted portions having a spotted 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 board. 2. The screw loosening detection device according to claim 1,

[0054] (Appendix 8) The monitoring means holds information indicating the conduction state of the plurality of conductive patterns when the screws are not loosened, and detects the loosening of the screws when the conduction state of the plurality of conductive patterns changes. 2. The screw loosening detection device according to claim 1,

[0055] (Appendix 9) A fastening component equipped with the screw loosening detection device according to any one of appendices 1 to 8, a screw having a shaft portion having a thread formed on its outer periphery and a head portion connected to one end of the shaft portion at its back surface, the back surface of the head portion having a portion with a recess and a portion without the recess; the washer has a hole through which the shank of the screw passes, and a plurality of leaf springs are provided around the hole, the leaf springs being formed so as to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the washer is attached to the screw; the substrate having a screw hole through which the shank of the screw passes, and a plurality of conductive patterns formed around the screw hole on a surface that faces the lower surface of the washer when the screw is attached to the screw hole; A fastening component comprising:

[0056] (Appendix 10) a screw comprising a shaft portion having a thread formed on its outer periphery and a head portion connected to one end of the shaft portion at its back surface, the back surface of the head portion having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, and a plurality of leaf springs formed to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the washer is attached to the screw, and the leaf springs are provided around the hole; a substrate having a screw hole through which the shank of the screw passes, the substrate having a surface facing the lower surface of the washer when the screw is attached to the screw hole, the surface having a plurality of conductive patterns formed around the screw hole; a fastening component comprising: a monitoring means for monitoring a state of conduction between each of the plurality of conductive patterns; A method for detecting loose threads using a loose thread detection device comprising: Among the plurality of leaf spring portions of the washer, a leaf spring portion in contact with a portion of the back surface of the screw that does not have the recess is pressed down by the back surface of the screw in a direction toward the substrate, 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 the one or more leaf spring portions, The monitoring means detects a change in the state of conduction of the plurality of conductive patterns due to the rotation of the screw relative to the washer. A method for detecting loose screws.

[0057] Furthermore, some or all of the configurations described in Supplementary Notes 2 to 8 that are dependent on Supplementary Note 1 above may also be dependent on Supplementary Note 10 in the same dependent relationship as Supplementary Notes 2 to 8. Furthermore, within the scope of each of the above-mentioned embodiments, some or all of the configurations described as Supplements may be made dependent on various hardware, software, various recording means for recording software, or systems.

[0058] The present disclosure has been described above 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. Furthermore, various modifications 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 loose screws attached to a printed circuit board. [Explanation of symbols]

[0060] 1. Screw loosening detection device 10 Fasteners 11 Screws 111 Shaft 112 Head 113 Back side 12 Washers 121 Leaf spring part 13 Conductive pattern 131 1st contacted part 132 2nd contacted part 20 Monitoring Department 30 Printed Circuit Board D. Depression H hole S screw hole

Claims

1. a screw comprising a shaft portion having a thread formed on its outer periphery and a head portion connected to one end of the shaft portion at its back surface, the back surface of the head portion having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, and a plurality of leaf springs formed to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the washer is attached to the screw, and the leaf springs are provided around the hole; a substrate having a screw hole through which the shank of the screw passes, the substrate having a surface facing the lower surface of the washer when the screw is attached to the screw hole, the surface having a plurality of conductive patterns formed around the screw hole; a fastening component comprising: a monitoring means for monitoring a state of conduction between each of the plurality of conductive patterns; Equipped with Among the plurality of leaf spring portions of the washer, a leaf spring portion in contact with a portion of the back surface of the screw that does not have the recess is pressed down by the back surface of the screw in a direction toward the substrate, 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 the one or more leaf spring portions, The monitoring means detects a change in the state of conduction of the plurality of conductive patterns due to the rotation of the screw relative to the washer. Screw loosening detection device.

2. The recess provided in the screw has a depth corresponding to the height of the leaf spring portion of the washer measured from the surface when the leaf spring portion rises obliquely from the surface.

2. The screw loosening detection device according to claim 1.

3. The recess provided in the screw has an annular sector shape.

2. The screw loosening detection device according to claim 1.

4. The leaf spring portion provided on the washer is formed by making a notch on the surface of the washer and lifting a protrusion formed on the washer from the surface of the washer.

2. The screw loosening detection device according to claim 1.

5. The plurality of conductive patterns are formed on a surface of a printed circuit board fixed by the screws, and the monitoring means is disposed on the printed circuit board and electrically connected to the plurality of conductive patterns.

2. The screw loosening detection device according to claim 1.

6. The plurality of conductive patterns include a first contacted portion having a ring shape corresponding to the size of the washer, and the first contacted portion comes into contact with at least a peripheral portion of the washer when the shank of the screw passes through the hole of the washer.

2. The screw loosening detection device according to claim 1.

7. The plurality of conductive patterns include a plurality of second contacted portions having a spotted 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 board.

2. The screw loosening detection device according to claim 1.

8. The monitoring means holds information indicating the conduction state of the plurality of conductive patterns when the screws are not loosened, and detects the loosening of the screws when the conduction state of the plurality of conductive patterns changes.

2. The screw loosening detection device according to claim 1.

9. A fastening component equipped with the screw loosening detection device according to any one of claims 1 to 8, a screw having a shaft portion having a thread formed on its outer periphery and a head portion connected to one end of the shaft portion at its back surface, the back surface of the head portion having a portion with a recess and a portion without the recess; the washer has a hole through which the shank of the screw passes, and a plurality of leaf springs are provided around the hole, the leaf springs being formed so as to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the washer is attached to the screw; the substrate having a screw hole through which the shank of the screw passes, and a plurality of conductive patterns formed around the screw hole on a surface that faces the lower surface of the washer when the screw is attached to the screw hole; A fastening component comprising:

10. a screw comprising a shaft portion having a thread formed on its outer periphery and a head portion connected to one end of the shaft portion at its back surface, the back surface of the head portion having a portion with a recess and a portion without the recess; a washer having a hole through which the shank of the screw passes, and a plurality of leaf springs formed to rise from an upper surface facing the back surface of the screw in a direction toward the back surface when the washer is attached to the screw, and the leaf springs are provided around the hole; a substrate having a screw hole through which the shank of the screw passes, the substrate having a surface facing the lower surface of the washer when the screw is attached to the screw hole, the surface having a plurality of conductive patterns formed around the screw hole; a fastening component comprising: a monitoring means for monitoring a state of conduction between each of the plurality of conductive patterns; A method for detecting loose threads using a loose thread detection device comprising: Among the plurality of leaf spring portions of the washer, a leaf spring portion in contact with a portion of the back surface of the screw that does not have the recess is pressed down by the back surface of the screw in a direction toward the substrate, 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 the one or more leaf spring portions, The monitoring means detects a change in the state of conduction of the plurality of conductive patterns due to the rotation of the screw relative to the washer. A method for detecting loose screws.

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