JPH11287236A - Nut removal apparatus for preventing nut from being drawn out - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a nut from being drawn out to disappointment by screwing a first cover in the end part protruded from a nut screwed to a bolt fastening a member, putting a second cover covering the first cover and the nut over them, and connecting both covers together by means of a connecting means. SOLUTION: For preventing the dawing-out of a nut 13 screwed to an external thread 11 extending through first and second members 17, 19 tightly touching each other, a first cover 21 is installed to a tip part 11a protruded from the external thread 11 in the nut 13 by engaging an internal thread part 23 formed in the inner circumference so that an opening edge part 27 of the first cover 21 is brought into contact with one end 13b of the nut 13. A second cover 29 is arranged so as to cover the nut 13 and the first cover 21, and the second cover 29 is connected to the first cover 21 by means of a connecting member 39 constructed of a rod type member provided with a leg part 41 and a head part 43. In this process, the leg part 41 of the connecting member 39 is forcibly inserted into an opening formed in the bottom 25 of the first cover 21 so as to close it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nut removal preventing device, and more particularly, to a nut which is screwed into a male screw penetrating a member, one end of which is in contact with the member and the nut for tightening the member is unexpectedly loosened. The present invention relates to a device for preventing extraction.

[0002]

2. Description of the Related Art It is simple and reliable to fix a member to a male screw by screwing a nut to a male screw penetrating the member, bringing one end of the nut into contact with the member and tightening the member. Conventionally, it is often used as a method for fixing members. For example, almost all components that need to be connected and fixed, such as industrial machines, automobiles, high-rise buildings, houses, and independent towers, are used. The nut screwed into this male screw must be held at a position where the member can be sufficiently tightened and fixed.If the nut suddenly rotates with respect to the male screw and the member loosens, rattling or male screw may occur. There arises a problem that the member comes off from the contact. For this purpose, two or more nuts are screwed into the male screw, and members are tightened with the plurality of nuts. A pin hole is drilled in the male screw in the direction in which the nut is loosened, and a split pin or the like is inserted into the male screw. By applying and bonding an adhesive so as to straddle the member, the loosening due to the rotation of the nut is prevented.

[0004]

However, these conventional methods cannot prevent a malicious third party from loosening the nut. That is, by rotating and loosening the nut screwed to the male screw penetrating the member or removing the member from the male screw, a malicious third party who intentionally causes the member to play or removes the member from the male screw is desired. A person can easily rotate and loosen or pull out even a nut provided with the above-described conventional loosening prevention method. This is particularly important when the trouble is related to human life, and it is extremely important to prevent the trouble when a nut is tightened and fixed to a huge heavy object or an important part of a vehicle. For example, the collapse of a transmission line supporting tower that occurred in Sakaide City, Kagawa Prefecture in February 1998 resulted in extremely large losses, but according to one theory, a malicious third party intentionally deliberately damaged the base of the tower. It was also reported that this occurred due to the removal of the tightening nut from the bolt, and the importance of trouble caused by intentional removal of the nut was reported.

Accordingly, in the present invention, a nut which can be intentionally rotated to loosen a nut screwed into a male screw penetrating the member to prevent the nut from being loosened or pulled out from the male screw and to prevent the nut from loosening naturally. It is intended to provide a prevention device.

[0006]

Means for Solving the Problems To achieve the above object, a nut removal prevention device (hereinafter referred to as "the device") of the present invention is screwed into a male screw penetrating a member, one end of which is screwed. An instrument for preventing removal of a nut that abuts on the member and tightens the member, wherein a female screw portion formed on the inner circumference of the male screw protrudes from the other end of the nut and is screwed into the male screw. A first cover having a bottom hollow cylindrical shape, an opening end of which is in contact with the other end of the nut; a second cover having a bottomed hollow cylindrical shape covering the first cover and the nut; Wherein a distance between the open end and the member is smaller than at least a distance from the one end to the other end of the nut, and the second cover is parallel to a central axis of the male screw. The second cover is free to rotate about a rotation axis and As will be fixed with respect to a direction along the axis of the male screw, and has a connecting member for connecting said second cover to said first cover, and an instrument. By doing so, the open end of the first cover comes into contact with the other end of the nut (the so-called double nut), so that the nut does not rotate and loosen naturally, and the first cover is separated by the second cover. Because it is covered, it is not possible to rotate the first cover from the outside and remove it from the male screw, and since the second cover is free to rotate independently of the first cover, it is not possible to remove this device even by rotating the second cover. The nut cannot be turned and loosened or pulled out.

The present device is a device which is screwed into a male screw penetrating a member, one end of which is in contact with the member to prevent the nut from tightening the member. The male screw is
It passes through an opening formed in the member. The "male thread" as used in this specification may be any thread provided that a thread is threaded on the outer peripheral portion of the rod-shaped member, and a thread may be attached to the foot portion of the bolt or the end of the cylindrical rod material. Engraved ones can be exemplified. The member may be any member as long as it is fixed to the male screw by a nut. Even when only one member is fixed to the male screw, two or more members are penetrated by the male screw and the male screw May be fixed. The nut is screwed into the male screw, and one end of the nut (which is closer to the member out of the two surfaces substantially perpendicular to the direction in which the nut advances and retreats by rotating with respect to the male screw) contacts the member. Tighten and fix. Here, "the one end of the (nut) abuts on the member" includes the case where a washer or the like is appropriately disposed between the one end of the nut and the member. The nut may have any shape as long as it is screwed into the male screw,
Examples include a polygonal prism such as a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, a heptagonal prism, and an octagonal prism, an elliptical cylinder, and a gear shape in which irregularities are formed on side surfaces of a cylinder. The present device can be mounted as it is without processing ordinary male screws and nuts conventionally used.

[0008] The device has a first cover, a second cover, and a connecting member. First, the first cover has a bottomed hollow cylindrical shape in which a female screw portion formed on the inner periphery thereof is screwed to a distal end portion of a male screw projecting from the other end of the nut, and an open end portion of the nut is formed by the nut. Contact the other end. The first cover has a so-called cap nut structure, and has a hollow cylindrical shape with a bottom having only one bottom surface (for example, a shape similar to a cup). On the inner periphery of the first cover, a female screw portion with which the distal end of the male screw is screwed is formed. The first cover accommodates the distal end portion of the male screw projecting from the other end of the nut to the distal end of the male screw inside the first cover when the female screw portion is screwed. The first cover housing the distal end of the male screw therein is provided with an opening end portion of the first cover (a first cover defining an opening that connects the inside of the cylindrical tube formed by the first cover and the outside of the tube). The end of the nut is contacted with the other end of the nut (which is farthest from the member on both surfaces substantially perpendicular to the direction in which the nut advances and retreats due to the rotation of the nut with respect to the male screw), and the nut Press in the direction.
This prevents the nut from rotating and moving away from the member to loosen the member.

Next, the second cover is in the form of a hollow cylinder with a bottom covering the first cover and the nut, and the distance between the open end and the member is at least from one end of the nut to the other end. Less than the distance. Like the first cover, the second cover has a hollow cylindrical shape with a bottom having only one bottom surface (for example, a shape similar to a cup). The second cover is provided to cover the first cover and the nut. Since the second cover must be freely rotatable about a rotation axis parallel to the center axis of the male screw, the shape must be such that the second cover does not interfere with the first cover and the nut during the rotation. Must have. When the second cover covers the first cover, the first cover screwed with the male screw cannot be directly rotated (for example, by engaging a tool or the like) to remove the device and loosen the nut. For this reason, between the second cover and the member, that is, the opening end of the second cover (the end of the second cover defining the opening communicating the inside of the cylindrical tube formed by the second cover with the outside of the cylinder). If the distance between the member and the member is too large, the first cover can be removed by rotating the first cover by inserting a tool or the like through a gap formed between the opening end of the second cover and the member. It is preferable to make it as small as possible,
Preferably, the distance is at least smaller than the distance from one end to the other end of the nut (that is, the length of the nut), more preferably 1 mm or less, and most preferably 0.5 mm or less.
mm or less. On the other hand, the distance may be reduced to 0 (the opening end of the second cover comes into contact with the member), but when the opening end of the second cover presses the member, the reaction force of the first cover causes the first cover to move. It is not preferred because it is pulled (by the second cover) in the direction of being pulled out from the male screw, and the effect of the first cover for preventing the nut from loosening is reduced.

The sectional shape of the first cover and the second cover is not particularly limited as long as it has a hollow cylindrical shape with a bottom (a sectional shape formed by a plane perpendicular to the center axis of the male screw). Since there are many things, it is preferable to have a hollow cylindrical shape with a bottom so that the strength and the like do not differ in each direction. The cylindrical shape is preferable because the strength can be improved and the steel pipe can be easily manufactured using a commercially available steel pipe.

[0011] The connecting member is provided so that the second cover is free to rotate about an axis of rotation parallel to the central axis of the male screw and the second cover is fixed in a direction along the axis of the male screw. Connect the cover to the first cover. Since the connection member freely connects the second cover to the first cover around the rotation axis parallel to the central axis of the male screw,
Even when the second cover is rotated about the rotation axis, the opening end of the second cover does not contact the member, so that the second cover can be smoothly rotated. The “rotation axis parallel to the center axis of the male screw” as used herein includes the case where the rotation axis is on an extension of the center axis. In this case, a small second rotation axis is provided around the male screw. The two covers can be formed, and since the rotating shaft deviates from the extension of the central shaft, a crank mechanism formed by the rotating shaft and the central shaft is not generated. On the other hand, even if it moves along the vertical plane, there is no problem that the first cover is removed from the male screw by moving the second cover without rotating the first cover with respect to the male screw.
Due to the free rotation of the second cover, even if the second cover is rotated, the first cover is not rotated and the first cover cannot be removed. Also, since the connecting member connects the second cover to the first cover so as to be fixed in the direction along the axis of the male screw (the direction in which the second cover is removed), the second cover is connected along the axis of the male screw. Cannot be removed in the direction and cannot contact the first cover. As described above, even if the second cover is rotated, the first cover is not rotated, and since the first cover is covered by the second cover, contact with the first cover is prevented. It is impossible for a third party to intentionally loosen or remove the nut.

The connecting member may be any member that connects the second cover to the first cover as described above. For example, the connecting member is provided along the rotation axis of the second cover. There may be. When the connecting member is provided along the rotation axis of the second cover so that the attachment portion between the connecting member and the first cover is rotatable (the connecting member and the second cover are rotated by rotating the second cover. In the case where the attachment portion between the connecting member and the second cover is made rotatable (by rotating the second cover, the connecting member does not rotate and only the second cover rotates), the two attaching portions are rotated. Either case may be adopted in which both parts are rotatable, and the other part is made rotatable. By doing so, the structure of the connecting member can be simplified, and the manufacturing cost and man-hours of the device can be reduced.

When the connecting member is disposed along the rotation axis of the second cover, the connecting member is formed of a rod-shaped member having a foot and a head having a portion having a larger cross-sectional area than the foot, The second cover is a second cover bottom opening formed at the bottom thereof, and when the connecting member is inserted from the outside of the second cover to the inside through the second opening at the bottom with the foot at the head, the second cover has the outer peripheral surface of the head and the second cover. When the inner peripheral surface of the cover bottom opening abuts, further insertion of the connecting member is prevented, and the outer peripheral surface of the contacted head and the inner peripheral surface of the second cover bottom opening can slide. The second cover has a second cover bottom opening in which the second cover is rotatable around the head, and the connecting member is inserted from the outside of the second cover to the inside through the second cover bottom opening with the foot at the head. When the first cover can press the foot into the first It may have a bar bottom opening. The connecting member is formed by a rod-shaped member having a head and a foot. The head has a portion with a larger cross-sectional area than the cross-sectional area of the foot. Here, the cross-sectional area refers to an area in a cross section of a rod-shaped member taken along a plane perpendicular to the longitudinal direction. A second cover bottom opening is formed at the bottom of the second cover,
When the connecting member having the foot and the head is inserted from the foot to the inside of the second cover from the outside through the second cover bottom opening, the outer peripheral surface of the head and the inner periphery of the second cover bottom opening. Sliding contact with the surface prevents further insertion by allowing further rotation of the second cover about the head. Furthermore, when the connecting member is inserted into the inside of the second cover in this way, the first cover has a first cover bottom opening through which the foot can be pressed in, so that the first cover securely holds the foot of the connecting member. Can be fixed.
Therefore, by inserting the foot of the connecting member from the outside of the second cover into the inside through the second cover bottom opening, and pressing the foot into the first cover bottom opening, the head of the connecting member is centered. As a result, the second cover becomes free to rotate and the second cover cannot be removed from the first cover. The shape of the head and the second cover bottom opening is such that the outer peripheral surface of the head and the inner peripheral surface of the second cover bottom opening abut against each other to prevent further insertion by sliding. Anything can be used as long as the second cover can rotate around the center, for example, the head has a frustoconical shape in which the cross-sectional area decreases toward the foot, and the bottom opening of the second cover has this conical shape. You may make it have the inner peripheral surface which contacts a side surface of a trapezoid. The “truncated cone” used in the present specification refers to a portion including the bottom surface among two portions obtained by cutting a conical shape by a plane parallel to the bottom surface. Also, the head
The second cover bottom opening may have a stepped ring shape formed so that the radius decreases toward the foot, and the second cover bottom opening has an inner peripheral surface in contact with the stepped portion of the stepped ring.

In this device, the female screw portion of the first cover is rotated by rotation of the second cover (hereinafter referred to as "rotation of the second cover") about a rotation axis parallel to the central axis of the male screw. A fixing pin may be further provided for fixing the first cover to the second cover so as to rotate with respect to the external thread. The fixing pin is used when installing this device.
The first cover screwed to the male screw (with its female screw portion) is used to rotate the first cover by rotating the second cover, and further to screw it tightly with the male screw. A fixing pin is formed at a position of the first cover corresponding to the pin opening and the pin opening formed in the second cover in order to press-fit the fixing pin, and a pin tip receiving portion into which the tip of the fixing pin is fitted or press-fitted. When a force greater than a predetermined magnitude is applied, the portion between the portion pressed into the pin opening of the fixing pin and the tip portion is broken. A pin opening for press-fitting the fixing pin is formed in the second cover, and a pin tip receiving portion is provided at a position of the first cover corresponding to the pin opening when the device is mounted on the male screw and the nut. It is formed. The pin tip receiving portion has a shape into which the tip of the fixing pin can be fitted or press-fitted, and is usually formed as a concave portion or an opening formed on the surface of the first cover. The pin tip receiving portion may be any of the one into which the tip of the fixing pin is inserted or the one into which the tip of the fixing pin is press-fitted, as long as the torque transmitted by the fixing pin and rotating the first cover can be transmitted to the first cover. You may.

The fixing pin is wedge-fitted so as to communicate between the pin opening and the pin tip receiving portion, and the second cover is rotated to rotate the first cover in the same direction. The fixing pin rotates the first cover while receiving a bending force between the second cover and the first cover, and when the first cover is sufficiently tightened and the force for rotating the first cover is larger than a predetermined magnitude. As a result, the intermediate portion of the fixing pin (the portion between the portion press-fitted into the pin opening of the fixing pin and the front end portion) breaks down with the increased bending force and breaks. The breaking of the fixing pin allows the second cover to rotate independently of the first cover,
Thereafter, even if the second cover is rotated, the first cover cannot be rotated, so that a malicious third party can prevent the removal of the device. The first advantage of having this fixing pin is that when the second cover is rotated until the fixing pin breaks and the first cover is tightened, the second cover is rotated according to the breaking strength of the fixing pin (when there are a plurality of fixing pins, (This also relates to the number). The first cover is tightened with strength, and the first cover can be securely tightened with necessary and sufficient torque. The second advantage is that since the outer peripheral surface of the second cover is farther from the center of the male screw than the outer peripheral surface of the first cover, applying a force to the outer peripheral surface of the second cover generates a larger rotational torque, and Can be strongly tightened into the male screw. A third advantage is that the portion of the broken fixed pin pressed into the pin opening is firmly held in the pin opening as it is, so that the pin opening is securely closed and the first cover is loosened through the pin opening. Can be prevented. In addition, if irregularities with which the engaging portion of the tool (for example, a spanner or a wrench) that engages with the rotating object is formed on the outer peripheral surface of the second cover, the second cover can be easily and surely formed by the tool. This is preferable because the two covers (and also the first cover via the fixing pin) can be rotated.

Materials for manufacturing the device include metal materials (steel (including stainless steel), aluminum, magnesium, copper, and alloys containing these metals, etc.), resin materials (polyamide, polypropylene, etc.), and inorganic materials (Concrete, fine ceramics such as silicon nitride, etc.) can be used, but it is necessary to have sufficient strength against attacks by malicious third parties and to reduce manufacturing costs. It is preferable to use a metal material, and particularly to use steel (including stainless steel). The present device may be appropriately coated, coated, plated, etc. in order to impart weather resistance and the like.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings based on embodiments, but the present invention is not limited thereto.

FIG. 1 is a sectional view showing the male screw 11 and the nut 13 to which the present instrument 37 of one embodiment is attached. FIG. 1 shows a cut surface by a plane including the central axis 15 of the male screw 11. FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG.
4 is a sectional view taken along line CC of FIG. 1, and FIG. 5 is a sectional view taken along line DD of FIG. Referring to FIGS. 1 to 5, the male screw 11 penetrates the first member 17 and the second member 19 which are in close contact with each other. A nut 13 is screwed into the male screw 11.
Abuts on the second member 19 to fasten the first member 17 and the second member 19. A tip 11a of the male screw 11 projects from the other end 13b of the nut 13. A female screw portion 23 formed on the inner periphery of the first cover 21 is screwed into the distal end portion 11a of the male screw 11. The first cover 21 has a bottom 25
And has a hollow cylindrical shape. The open end 27 of the first cover 21 is in contact with the other end 13 b of the nut 13,
The nut 13 is prevented from loosening. A second cover 29 is provided to cover the nut 13 and the first cover 21. The second cover 29 has a hollow cylindrical shape having a bottom 31. The second cover 29 is connected to the first cover 21 by the connecting member 3.
9 are connected.

The connecting member 39 is formed of a rod-shaped member having a foot portion 41 and a head portion 43, and all cut surfaces cut by a plane including the axis have the same shape. That is,
The foot 41 has a cylindrical shape, and the head 43 has a truncated conical shape in which the cross-sectional area decreases toward the foot 41. The head 43 has a shape in which the radius increases as it goes away from the foot 41, and has a portion having a larger cross-sectional area than the foot 41. A second cover bottom opening 45 (in which the head 43 of the connecting member 39 is fitted in FIG. 1) is formed in the bottom 31 of the second cover 29, and the connecting member 39 starts with its foot 41 as its head. The second cover 29 is inserted from outside to inside via the second cover bottom opening 45. The outer peripheral surface of the head 43 of the connecting member 39 and the second cover bottom opening 45
And the inner peripheral surface of the second cover 29 is prevented from being inserted into the second cover 29 from outside to inside. The outer peripheral surface of the head 43 of the connecting member 39 and the inner peripheral surface of the second cover bottom opening 45 are in contact with each other in the state shown in FIG. Therefore, the second cover 29 is rotatable around the head 43 of the connecting member 39. On the other hand, the foot 41 of the connecting member 39 is closed by the first cover bottom opening formed in the bottom 25 of the first cover 21 (in FIG. 1, the foot 41 of the connecting member 39 is press-fitted). 7 (indicated by reference numeral 57 in FIG. 7), and the connecting member 39 is securely and firmly attached to the first cover 21. Therefore, the second cover 29 cannot move in the direction 47 in which the second cover 29 is removed from the state shown in FIG. 1 (that is, the second cover 29 is fixed with respect to the direction along the axis 15 of the male screw 11), and the connecting member It can only rotate around the head 43 of 39 (this rotation does not rotate the first cover 21, so that the first cover 21 cannot be rotated and removed with respect to the male screw 11). The movement in the direction opposite to the removing direction 47 is performed by the opening end 33 of the second cover 29 and the second member 1.
9 is limited by the contact. Further, a matching mark may be formed on the head 43 of the connecting member 39 and the second cover 29 so that the rotational position of the second cover 29 with respect to the head 43 of the connecting member 39 can be known. The matching mark may be of any type.
The mark may be formed so as to be visible from the outside of the instrument so as to straddle the head 43 and the second cover 29. In this way, if the two marks are aligned when the inspection is performed, it is possible to know whether or not the second cover 29 has been rotated (touched) by a third party until the next inspection. Inspections can be focused on those contacted by third parties.

The distance 35 between the opening end 33 of the second cover 29 and the second member 19 is about 0.5 mm, and the distance 35 from the one end 13a to the other end 13b of the nut 13 is about 20 mm.
The first cover 21 cannot be removed from the male screw 11 by rotating the first cover 21 through a gap between the opening end 33 of the second cover 29 and the second member 19. Therefore, a malicious third party cannot remove the device 37 and rotate the nut 13 to remove it. Even if the nut 13 is rotated and removed in the state of FIG. 1, since the opening end 27 of the first cover 21 is in contact with the other end 13 b of the nut 13, the nut 13 is pulled out in the direction ( Cannot be moved.

In the case of the present embodiment, the rotation shaft 49 of the second cover 29 exists on an extension of the center axis 15 of the male screw 11.
This is an embodiment in which the rotation shaft 49 of the second cover 29 is parallel to the central axis 15 of the male screw 11. Since the rotation shaft 49 of the second cover 29 is on an extension of the center axis 15 of the male screw 11, a small second cover 29 can be formed around the male screw 11, and the rotation shaft 49 is The rotation axis 49 and the central axis 1
5 does not produce a crank mechanism, so that even if the second cover 29 is moved along a plane perpendicular to the central axis 15, the second cover 29 does not generate a force for rotating the first cover 21 with respect to the male screw 11. By moving 29, the first cover 21
Does not occur from the external thread 11. Further, since the connecting member 39 is disposed along the rotation shaft 49 of the second cover 29, the structure of the connecting member 39 can be simplified, and the manufacturing cost and manufacturing man-hour of the device 37 can be reduced. be able to.

Although the present device may not have a fixing pin, the present device of the present embodiment used a device having a fixing pin. The fixing pin is used when the present device is attached to the male screw 11 and the nut 13. By rotating the second cover 29, the first cover 21 is rotated via the fixing pin and the first cover 21 is securely and securely attached to the male screw 11. Used for tight screwing. When the first cover 21 is sufficiently screwed into the male screw 11 and a force greater than a predetermined magnitude is applied, a portion between the first cover 21 and the second cover 29 of the fixing pin is broken, and The second cover 29 can freely rotate. FIG. 1 shows a state in which the fixing pin is broken, and the front end portion 51 a of the fixing pin fitted into the pin front end receiving portion formed on the first cover 21 and the pin opening formed on the second cover 29. The portion between the press-fitted fixing pin and the main body 51b is broken, and the second cover 29 can rotate freely with respect to the first cover 21. For this reason, by rotating the second cover 29, the first cover 21 can be strongly screwed into the male screw 11 by a force until the fixing pin is broken, but thereafter,
The intermediate portion of the fixing pin is broken, so that even if the second cover 29 is rotated, the first cover 21 cannot be rotated, thereby preventing a malicious third party from removing the device. In addition, since the outer peripheral surface of the second cover 29 is formed with a concave portion 53 in which an engaging portion of a tool (for example, a spanner or a wrench) is engaged, the second cover 29 can be easily and reliably rotated by the tool. It is preferable because the first cover 21 can be rotated through the fixing pin.

Next, each component constituting the instrument of the present embodiment will be described. In addition, all the parts which comprise this instrument are formed of steel materials. FIG. 6 is a cross-sectional view of the second cover 29, and shows a state where the second cover 29 is cut along the same cut surface as in FIG. Referring to FIG. 6, the second cover 29 has a hollow cylindrical shape, and has a bottom 31 at one end of the cylinder and an open end 33 at the other end of the cylinder. A second cover bottom opening 45 is formed in the bottom 31. Further, pin openings 55a and 55b for press-fitting the fixing pins are formed in a cylindrical shape on a cylindrical side portion. Further, a tool (for example, a spanner or a wrench) is provided on the outer peripheral surface of the second cover 29.
The recessed portion 53 with which the engaging portion is engaged is formed.

FIG. 7 is a cross-sectional view of the first cover 21 and shows a section cut along the same cut surface as in FIG.
Referring to FIG. 7, the first cover 21 has a hollow cylindrical shape, and has a bottom 25 at one end of the cylinder and an open end 27 at the other end of the cylinder. A first cover bottom opening 57 into which the foot 41 of the connecting member 39 is press-fitted is formed in the bottom 25. The first cover bottom opening 57 is formed in a size that allows the foot 41 of the connecting member 39 to be press-fitted to securely and firmly fix the foot 41. Also, a pin tip receiving portion 59a into which the tip portion 51a of the fixing pin is fitted,
59b is formed on the outer peripheral surface of the first cover 21 as a cylindrical concave portion. A female screw portion 23 is formed on the inner periphery of the first cover 21.

FIG. 8 is a sectional view of the connecting member 39, and FIG.
The figure shows a section cut by the same cutting plane as that shown in FIG. Referring to FIG. 8, connecting member 39 is formed of a rod-shaped member having a foot portion 41 and a head portion 43, and all cut surfaces by a plane including the axis have the same shape. That is, the foot portion 41 has a cylindrical shape (the tip portion 41a has a truncated cone shape), and the head portion 43 has a truncated cone shape in which the cross-sectional area decreases toward the foot portion 41. The head 43 has a shape in which the radius increases as it goes away from the foot 41, and has a portion having a larger cross-sectional area than the foot 41.

FIG. 9 is a cross-sectional view of the fixing pin 51, and shows a cross section cut by a plane including the central axis 52 thereof. Referring to FIG. 9, fixing pin 51 has a rotationally symmetric shape with respect to center axis 52, and has the same shape as that of FIG. 9 even when cut along any surface including center axis 52. The fixing pin 51 includes a tip 51a, a main body 51b, and a tip 51.
a and the main body 51b. The tip portion 51a is the first cover 2
1 are fitted into the pin tip receiving portions 59a and 59b (see FIG. 7). The main body 51b is pressed into pin openings 55a, 55b (see FIG. 6) formed in the second cover 29. As a result, the second cover 29 and the first cover 21 are fixed by the fixing pins 51, and the first cover 21 is rotated by rotating the second cover 29.
Is strongly screwed into the male screw 11. When the first cover 21 is screwed into the male screw 11 sufficiently firmly, the force applied between the main body 51b and the distal end 51a of the fixing pin 51 increases, and when the force exceeds a predetermined magnitude, the break 51c is formed. It breaks and the second cover 29 can freely rotate with respect to the first cover 21. As described above, the first cover 21
(Torque) for screwing into the male screw 11
The thickness can be freely set by changing the thickness of c, the material of the fixing pin 51, the number of the fixing pins 51, and the like.

Further, a method of attaching the present device, which is constituted by the second cover 29, the first cover 21, the connecting member 39, and the fixing pin 51, to the male screw 11 and the nut 13 screwed thereto will be described. . FIG. 10 shows a male screw 11 for mounting the device and a nut 1 screwed thereto.
FIG. FIG. 10 shows the center axis 1 of the male screw 11.
5 shows a cut surface by a plane including 5. Male thread 11
Penetrates the first member 17 and the second member 19 which are in close contact with each other. A nut 13 is screwed into the male screw 11, and the nut 13 is rotated so as to advance in the direction of the second member 19. One end 13a of the nut 13 contacts the second member 19, and the first member 17 and the second member 19 is tightened. A tip 11a of the male screw 11 projects from the other end 13b of the nut 13.

FIG. 11 is a cross-sectional view showing a first step of mounting the present instrument, and shows the distal end 1 of the male screw 11 shown in FIG.
1a shows a state where the first cover 21 is screwed into the first cover 1a. Referring to FIG. 11, female screw portion 23 formed on the inner periphery of first cover 21 is screwed into distal end portion 11 a of male screw 11, and first cover 21 is rotated to advance in the direction of nut 13. The opening end 27 of the first cover 21 contacts the other end 13b of the nut 13 with a sufficient force. Therefore, it is possible to reliably prevent the nut 13 from rotating in the loosening direction.

FIG. 12 is a cross-sectional view showing a second step of mounting the present device, and shows a state where the second cover 29 is arranged so as to cover the first cover 21 and the nut 13 shown in FIG. . Referring to FIG. 12, second cover 2 is positioned such that first cover bottom opening 57 of first cover 21 and second cover bottom opening 45 of second cover 29 are aligned.
9 are arranged. The connecting member 39 is being inserted toward the second cover bottom opening 45 with the foot portion 41 being the head. The foot 41 of the connecting member 39 is inserted through the second cover bottom opening 45 and is pressed into the first cover bottom opening 57 of the first cover 21. On the other hand, the outer peripheral surface 43 a of the head 43 of the connecting member 39 is in contact with the inner peripheral surface 45 a of the second cover bottom opening 45. Due to this contact, the second cover 29 cannot be removed from the connecting member 39, and the outer peripheral surface 43a and the inner peripheral surface 45a are slidable, so that the second cover 29 can rotate around the head 43. .

FIG. 13 is a cross-sectional view showing a third step of mounting the present instrument, and shows a state where the connecting member 39 shown in FIG. 12 has been completely inserted. Referring to FIG. 13, foot 41 of connecting member 39 is press-fitted into a first cover bottom opening (closed by press-fitting foot 41) of first cover 21, and first cover 21 is closed. It can be seen that the connecting member 39 is securely and firmly fixed to 21. Connecting member 39
The outer peripheral surface of the head 43 of the second cover bottom opening 45 (head 4
3 is closed by being fitted thereinto) so that the second cover 29 cannot be removed and the second cover 29 is rotatable. On the other hand, the pin openings 55a and 55b and the pin tip receiving portions 59a and 59b are arranged at corresponding positions. The fixing pin 51 is being inserted into the second cover 29 through the pin openings 55a and 55b with the tip end 51a at the head. Note that the fixing pin 51 is not indispensable to the present device, and the state shown in FIG. 13 before the fixing pin 51 is inserted (the pin openings 55a and 55b can be removed by rotating the first cover 21 therethrough. However, it is preferable that they do not exist to prevent this.).

FIG. 14 is a cross-sectional view showing a fourth step of mounting the present device, and shows a state where the fixing pin 51 shown in FIG. 13 has been completely inserted. Referring to FIG. 14, the distal end portion 51a of the fixing pin 51 has a pin distal end receiving portion 59a,
9b (the front end 51a is closed by being fitted)
The main body 51b is inserted into the pin openings 55a, 5a.
5b. For this reason, the second cover 29 and the first cover 21 are fixed by the fixing pins 51, and by rotating the second cover 29, the first cover 21 is
1 can be rotated. When the first cover 21 is screwed sufficiently tight with the male screw 11, the tip 51
A force exceeding a predetermined magnitude is applied between the body 51a and the body 51b, and a break 51c between the tip 51a and the body 51b.
Is broken. The state in which the breaking portion 51c is broken is the state shown in FIG. 1, whereby the second cover 29 can freely rotate independently of the first cover 21.

It is needless to say that the present invention is not limited to the above-described embodiment, and further includes the scope substantially equivalent to the claims.

[0033]

Since the present invention is configured as described above, it has the following effects. That is, in the device of the present invention, since the open end of the first cover abuts on the other end of the nut (the so-called double nut state), the nut does not rotate and loosen, and the first cover is not loosened. Since it is covered by the second cover, it cannot be removed from the external thread by rotating the first cover directly from the outside, and the second cover is free to rotate independently of the first cover, so even if the second cover is rotated, the first cover Can not be rotated and the appliance cannot be removed, so in addition to preventing the nut from loosening naturally, a malicious third party must rotate the nut to which the appliance is attached and loosen or remove it. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a male screw and a nut to which the present device of one embodiment is attached.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 1;

FIG. 5 is a sectional view taken along line DD of FIG. 1;

FIG. 6 is a cross-sectional view of a second cover used in the present device shown in FIGS. 1 to 5;

FIG. 7 is a cross-sectional view of a first cover used in the present device shown in FIGS. 1 to 5;

FIG. 8 is a sectional view of a connecting member used in the present device shown in FIGS. 1 to 5;

FIG. 9 is a cross-sectional view of a fixing pin used in the present device shown in FIGS. 1 to 5;

FIG. 10 is a sectional view showing a male screw for mounting the device shown in FIGS. 1 to 5 and a nut screwed thereto.

FIG. 11 is a sectional view showing a first step of mounting the present device shown in FIGS. 1 to 5;

FIG. 12 is a sectional view showing a second step of installing the present device shown in FIGS. 1 to 5;

FIG. 13 is a sectional view showing a third step of mounting the present device shown in FIGS. 1 to 5;

FIG. 14 is a sectional view showing a fourth step of attaching the present device shown in FIGS. 1 to 5;

[Explanation of symbols]

 11 Male Thread 11a Tip of Male Thread 13 Nut 13a One End of Nut 13b Other End of Nut 15 Center Axis of Male Thread 17 First Member 19 Second Member 21 First Cover 23 Female Thread Formed on First Cover 25 First Cover Bottom 27 Open end of first cover 29 Second cover 31 Bottom of second cover 33 Open end of second cover 37 This instrument 39 Connecting member 41 Foot of connecting member 43 Head of connecting member 43a Head of connecting member Outer peripheral surface of part 45 Second cover bottom opening 45a Inner peripheral surface of second cover bottom opening 47 Removal direction 49 Rotation axis of second cover 51 Fixed pin 51a Tip end of fixed pin 51b Body part of fixed pin 51c Fixed pin Breaking part 52 Center axis of fixing pin 53 Depression part 55a, 55b with which engaging part of tool engages Pin opening 57 First cover bottom opening 59 a, 59b Pin tip receiving part

Claims (8)

[Claims] 1. An instrument which is screwed into a male screw penetrating a member, one end of which is in contact with the member to prevent removal of a nut for tightening the member, the male screw protruding from the other end of the nut. A first cover in the form of a bottomed hollow cylinder into which a female screw portion formed on the inner periphery of the first cover is screwed to a tip end of the first cover, the open end of which is in contact with the other end of the nut; A second cover having a bottomed hollow cylindrical shape for covering the cover and the nut, wherein a distance between the open end and the member is at least smaller than a distance from the one end to the other end of the nut. The cover and the second cover such that the second cover is free to rotate about an axis of rotation parallel to the central axis of the male screw and the second cover is fixed with respect to a direction along the axis of the male screw. A connecting member for connecting the two covers to the first cover. Things, appliances. 2. The device according to claim 1, wherein the rotation axis of the second cover is on an extension of a center axis of the external thread. 3. The device according to claim 1, wherein the connecting member is disposed along the rotation axis of the second cover. 4. The device according to claim 3, wherein the connecting member is formed of a rod-shaped member having a foot and a head having a portion having a larger cross-sectional area than the foot. Is a second cover bottom opening formed at the bottom thereof, and the outer peripheral surface of the head when the connecting member is inserted from the outside to the inside of the second cover through the foot with the foot at the head. The inner peripheral surface of the second cover bottom opening prevents the connection member from being inserted further by contacting the inner peripheral surface of the second cover bottom opening, and the outer peripheral surface of the head and the inner peripheral surface of the second cover bottom opening. Has a second cover bottom opening in which the second cover is rotatable about the head by being slidable, and from the outside of the second cover to the inside through the second cover bottom opening. When the connecting member is inserted with the foot portion as the head,
The device wherein the first cover has a first cover bottom opening through which the foot can be pressed. 5. The device of claim 4, wherein said head is frusto-conical in shape with a decreasing cross-sectional area toward said foot. 6. The device according to claim 1, wherein the rotation of the external thread is parallel to a central axis of the external thread.
A fixing pin for fixing the first cover to the second cover so that the female screw portion of the first cover is rotated with respect to the male screw by rotation of the second cover, wherein the fixing pin is press-fitted. A wedge between a pin opening formed in the second cover and a pin tip receiving portion which is formed at a position of the first cover corresponding to the pin opening and into which the tip of the fixing pin is fitted or pressed. The fixing pin further comprises a fixing pin, wherein when a force greater than a predetermined magnitude is applied, a portion of the fixing pin between the portion pressed into the pin opening and the tip portion is broken. , Appliances. 7. The device according to claim 6, wherein the outer peripheral surface of the second cover is formed with irregularities for engaging an engaging portion of a tool. 8. The first cover and / or the second cover,
8. A hollow cylindrical shape with a bottom.
The appliance according to any one of the above.