JP2007051734A - Locking structure for bolt and nut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reusable locking structure for a bolt and nut with remarkably high reliability as a locking structure. <P>SOLUTION: The locking structure for a bolt and nut is provided with a bolt 1 formed with one or more grooves 1b extending in a direction orthogonal to its axis, a nut 2 formed with one or more grooves 2b extending in a direction orthogonal to its axis, and a lock-key member 3 inserted into the bolt and nut and preventing loosening of the nut 2. The lock-key member 3 has a body part 3a inserted into the groove 1b of the bolt 1 and the groove 2b of the nut 2, a stopper 3b abutting on the nut 2 to stop insertion of the body part 3a into the bolt and nut, and a fastening claw 3c provided on the body part 3a. The fastening claw 3c elastically deforms when the body part 3a is being inserted into the bolt and nut, and its attitude is restored after the body part 3a is inserted into the bolt and nut to prevent loosening of the body 3a from the bolt and nut. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bolt / nut loosening prevention structure that stops loosening of a nut screwed to a bolt, and more particularly, to a mechanical locking type bolt / nut loosening prevention structure.

  There are two types of bolts and nuts to prevent loosening: a system that increases the friction force and a mechanical lock system. Typical examples of the former include double nuts and spring nuts. A typical example of the latter is a JIS-compliant grooved nut used in combination with a split pin.

  The latter mechanical locking type locking structure will be described in detail. First, prepare a relatively thin linear pin or split pin, a grooved nut, and a bolt with a perforated hole, align the horizontal hole of the bolt and the groove of the grooved nut, and then insert the pin or split pin. Insert the grooved bolt side hole and grooved nut groove to limit the nut turning. And the front-end | tip part of a pin or a split pin is bent, and it prevents that a pin or a split pin comes off from a volt | bolt nut.

However, the conventional mechanical locking type loosening prevention structure has a drawback that the pin that has been bent is plastically deformed, so that the pin once used cannot be reused for retightening. In order to solve this drawback, Patent Document 1 provides a locking portion that can be elastically deformed at the tip of the split pin. When the split pin is inserted into the through hole of the bolt, the locking portion is elastically deformed, while A locking structure is disclosed that prevents the split pin from coming off by restoring the locking portion after passing through the hole (see Patent Document 1, paragraph number 0005). A split pin having a similar structure is also disclosed in Patent Document 2.
Japanese Utility Model Publication No. 7-16016 JP-A-9-203405

  However, in the split pins described in Patent Documents 1 and 2, a thin linear member having the same cross section is bent to form the split pin and the locking portion. The strength of the pin becomes the same, and the strength of the split pin cannot be increased. Therefore, when a strong rotational force is applied to the nut, the split pin may be broken by a shearing force generated at the boundary between the bolt and the nut. That is, the bolt / nut locking structure using the split pin cannot be used where a strong return rotational force is applied to the nut, and its reliability is lowered.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bolt / nut loosening prevention structure that can be reused and that has a remarkably high reliability as the loosening prevention structure.

  In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a bolt in which one or more grooves or through holes extending in a direction orthogonal to the axis thereof are formed in the head and a direction orthogonal to the axis. A nut in which one or more grooves are formed in one seating surface, or a nut in which one or more through holes extending in a direction perpendicular to the axis thereof are formed in the side surface, the direction of the bolt groove or through hole, A bolt / nut locking structure comprising a lock / key member that is inserted into a communication hole that passes through the bolt / nut that appears when the direction of the groove or through-hole of the nut is synchronized, and prevents the nut from loosening. The lock key member stops the insertion of the main body portion into the communication hole by contacting the outer edge of the nut and the main body portion inserted into the communication hole penetrating the bolt and nut. A top claw and a locking claw provided on the main body, and the locking claw is elastically deformed when the main body is inserted into the communication hole, while the main body is in the communication hole. It is characterized in that the main body portion is prevented from coming out of the communication hole by being restored in posture after being inserted and reaching a predetermined position.

  The invention according to claim 2 is the bolt / nut loosening prevention structure according to claim 1, wherein the bolt is provided with one or more through holes extending in a direction perpendicular to the axis thereof. Synchronized cutout grooves are formed in the top of the bolt.

  The invention according to claim 3 is the bolt / nut loosening prevention structure according to claim 1 or 2, wherein the nut has one or more grooves formed in one seating surface extending in a direction perpendicular to the axis, or In a nut in which one or more through-holes extending in a direction perpendicular to the axis are formed on the side surface, a notch groove that is synchronized with the direction of the groove or the through-hole is formed on the other seating surface of the nut. It is characterized by being.

  According to a fourth aspect of the present invention, in the bolt / nut locking structure according to any one of the first to third aspects, the locking claw of the lock / key member is a thread valley portion on the inner peripheral surface of the nut. And the main body portion is prevented from coming off from the communication hole penetrating the bolt and nut.

  According to a fifth aspect of the present invention, in the bolt / nut locking structure according to any one of the first to fourth aspects, the total length of the lock / key member is the total length of the communication hole penetrating the bolt / nut. On the other hand, it is characterized by being at least 10% longer.

According to a sixth aspect of the present invention, in the bolt / nut locking structure according to any one of the first to fourth aspects, the total length of the lock / key member is the total length of the communication hole penetrating the bolt / nut. It is characterized by substantially matching.

  A seventh aspect of the present invention is the bolt / nut locking structure according to any one of the first to sixth aspects, wherein the nut is a square nut.

  According to an eighth aspect of the present invention, in the bolt / nut locking structure according to any one of the first to sixth aspects, the nut is a round nut.

  A ninth aspect of the present invention is the bolt / nut locking structure according to any one of the first to sixth aspects, wherein the nut is a nut comprising a square part and a round part. It is characterized by.

  According to a tenth aspect of the present invention, in the bolt / nut locking structure according to any one of the first to ninth aspects, the cross-sectional area of the main body of the lock / key member is equal to the cross-sectional area of the locking claw. It is characterized by being significantly larger than that.

  According to an eleventh aspect of the present invention, in the bolt / nut locking structure according to any one of the first to tenth aspects, the cross-sectional shape of the main body portion of the lock / key member is a square shape or a substantially square shape. It is characterized by that.

  According to the first aspect of the present invention, the main body has a function of receiving a large shearing force generated at the boundary between the bolt and the nut, and a function of preventing the lock key member from coming off the bolt and nut. Since the latching claw that is elastically deformed is provided, a bolt / nut loosening prevention structure that can be reused and that has a remarkably high reliability as the loosening prevention structure is obtained.

  According to the second aspect of the present invention, the operator can know the direction and the number of the through holes formed in the bolt only by standing on the head side of the bolt with the notch groove as a mark. Can do. The operator can also easily know the position of the communication hole passing through the bolt and nut into which the lock / key member is to be inserted later by using the notched groove as a mark.

  According to the invention described in claim 3, the operator knows the direction and the number of the grooves or the through holes on the back surface of the nut only by standing on the head side of the bolt with the notched groove as a mark. Therefore, the operation of constructing the communication hole that passes through the bolt and nut in abutment with the groove or through hole of the bolt is facilitated. The operator can also read the tightening rotation stroke length of the nut when the tightening is performed with the notch groove as a mark.

  According to the fourth aspect of the present invention, the locking claw of the lock / key member engages with the thread valley portion on the inner peripheral surface of the nut. How to remove is not easily understood. Therefore, the lock key member is sealed, and the lock key member cannot be easily removed by mischief.

  According to the fifth aspect of the present invention, it is possible to prevent the operator from forgetting to attach the lock key member. In addition, whether or not the nut is correctly installed without loosening can be confirmed by visually confirming the appearance and location of the lock and key member protruding from the nut, and maintenance work attached to each bolt and nut can be omitted. .

  According to the sixth aspect of the present invention, since the presence of the lock / key member cannot be easily visually recognized from the bolt head side, the sealing effect is higher.

  According to the invention described in claim 7, a general-purpose tool can be used to tighten the nut.

  According to invention of Claim 8, since a general purpose tool cannot be used, the sealing effect becomes higher. Moreover, the number of through holes can be set randomly.

  According to the ninth aspect of the invention, a general-purpose tool can be used to tighten the nut. Moreover, the number of through holes can be set randomly.

  The conventional method using the split pin is limited to a material having a relatively small diameter. However, in the invention according to the tenth aspect, since the cross-sectional area of the main body of the lock / key member can be set large according to the magnitude of the shear stress, the reliability is significantly increased.

  According to invention of Claim 11, the directionality of the latching claw with respect to a main-body part can be given.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a bolt / nut locking structure according to an embodiment of the present invention. The bolt and nut locking structure according to this embodiment includes a bolt 1 that is threaded, a nut 2 that fits into the bolt 1, and a lock key that is inserted into the bolt 1 and nut 2 to prevent the nut 2 from loosening. It is comprised by 3 members with the member 3. In this embodiment, the bolt / nut loosening prevention structure of the present invention is applied to the holding side nut 2 of the double nuts 2 and 4. First, the structure of each part will be described.

<About bolts>
As shown in FIG. 2, the head 1 'of the bolt 1 that is threaded is provided with two deep grooves 1b extending in a direction perpendicular to the axis. The groove 1b passes through the axis of the bolt 1 as viewed from the axial direction of the bolt 1 and intersects in a cross shape. The depth of the groove 1b is calculated by adding the protrusion of the bolt head 1 'from the nut 2, which is required when the nut 2 is completely tightened, the height of the nut 2, and the amount necessary for retightening. Become deep. Therefore, the groove 1b is a relatively deep groove. As shown in FIG. 3, the lock / key member 3 is inserted into the groove 1b.

  Here, when the deep groove 1b is formed from the top 1a of the bolt 1, since the top 1a side of the bolt 1 is open, the locking claw 3c (the locking claw 3c of the lock / key member 3 is visually observed. Can be operated using a general-purpose driver or the like through the groove 1b. For this reason, there is an advantage that it is convenient for attaching / detaching the lock / key member 3. On the other hand, since the notch of the bolt 1 is long, the strength of the bolt 1 is reduced accordingly, and there is a disadvantage that it is not suitable for applications where a large force is applied. However, if it is used as a so-called double nut 2 or 4 used in combination with a general-purpose nut 4, this drawback can be covered.

<About nuts>
The nut 2 of this embodiment is a general-purpose (JIS standard) nut, for example, a type obtained by adding partial processing to a hexagonal nut.

  A type of nut 2 in which processing is applied to a general-purpose nut is a type in which a part of the back side of the general-purpose nut is cut to form a cylindrical portion 2a, and a groove 2b in which the lock / key member 3 is seated is provided in the cylindrical portion 2a. The nut 2 can be divided into a type in which only the groove 2b is processed. First, the former type will be described.

  4 and 5 show the former type of nut. The nut 2 includes a square part and a round part. That is, a cylindrical portion 2 a is provided on a part of the back side of the square nut 2 by cutting the corner portion. A groove 2b extending in a direction perpendicular to the axis of the nut 2 is provided on the back surface (clamping surface) of the nut 2. When the groove 2b is extended, it passes through the axis of the nut 2. The twelve grooves 2b are provided, for example, at equal intervals in the circumferential direction. Then, as shown in FIG. 6, the lock / key member 3 is inserted into the groove 2b.

  A notch groove 2c synchronized with the groove 2b provided on the back seat surface is formed on the viewing surface of the nut 2 on the viewing side. The depth of the notch groove 2c is shallower than the groove 2b, and is set to about 1 to 3 mm, for example. When this notch groove 2 c is also extended, it passes through the axis of the nut and is arranged radially from the axis of the nut 2.

  FIG. 7 shows a nut of the latter type, that is, a type in which only the groove 2b is formed in the general-purpose nut 2. A groove 2b extending in a direction perpendicular to the axis of the nut 2 is provided on the back surface (clamping surface) of the nut 2. The groove 2b is orthogonal to the planar portion 2d of the outer shape of the hexagonal nut 2 and is disposed at the center of the planar portion 2d. In FIG. 7, a total of six grooves 2 b are arranged radially from the axis of the nut 2. On the surface of the nut 2 on the viewing side, a notch groove 2c synchronized with the groove 2b provided on the back side is formed. Since the notch groove 2c is synchronized with the groove 2b on the back side of the nut 2, a total of six notch grooves 2c are also provided radially.

  The nut 2 of the type obtained by processing these general-purpose nuts has a convenience that can be rotated using a general-purpose spanner. In addition, the nut 2 shown in FIG. 7 has the advantage that the cost can be reduced, but since the number of grooves is six, the angle for obtaining the minimum stroke length at the time of retightening is 60 degrees ( To be precise, when the number of the split groove 1b of the bolt 1 is one, it is 60 degrees, and when it is two, it is 30 degrees). In other words, since the maximum number of communication holes that penetrate the bolts and nuts is limited to the same number as the number of corners of the nut, the minimum stroke length when the communication holes are obtained by rotating the nut 2 is increased. In addition, when providing a groove | channel or a through-hole in the side surface of a square nut, unless it provides in the side surface orthogonal to the axis line, the length of a communicating hole will fluctuate.

  On the other hand, in the nut 2 shown in FIGS. 4 and 5, since there is no corner portion of the nut 2, at least twelve grooves can be provided. For this reason, the angle for obtaining the minimum stroke length in the case of retightening is 30 degrees (exactly, when the number of the split groove 1b of the bolt 1 is one, it is 30 degrees, and when it is two, the angle is 15 degrees. Become). However, as the number of grooves is increased, the strength slightly decreases, and a specially designed nut is required, which increases the cost of the dedicated nut member.

<About lock and key members>
This is a member that embodies the characteristic configuration of the present invention. The lock / key member 3 has a sword-like shape and includes a main body 3a that extends linearly and a hook-shaped stopper 3b that projects from the main body 3a. The main body 3a is made of a hard metal rod-shaped square member having a large mass. Since the main body 3a is inserted into a communication hole passing through the bolt and nut, that is, the groove 1b of the bolt 1 and the groove 2b of the nut 2, it receives a large shearing force. Therefore, a metal that is difficult to deform and has a large mass is used.

  The cross-sectional shape of the main body 3a is a square shape or a substantially square shape. The cross-sectional shape of the main body 3a is preferably a horizontally long rectangle, and the bolt / nut groove into which the lock / key member 3 is inserted is also preferably an elongated rectangle. This is because the direction of the locking claw 3c with respect to the main body portion 3a is provided so that the locking claw 3c can be reliably caught on the inner periphery of the nut 2.

  A stopper 3b is provided at the end of the main body 3a. The stopper 3b contacts the outer edge of the nut 2 and stops the insertion of the main body 3a into the communication hole.

  From the stopper 3b of the main body 3a, a leaf spring-like locking claw 3c rises toward the stopper 3b. That is, the locking claw 3c is gently bent so as to gradually move away from the main body 3a toward the stopper 3b (the inclination angle from the main body 3a is about 5 degrees at the maximum). A spring material made of a material different from that of the main body 3a is used for the locking claw 3c, and the locking claw 3c and the main body 3a are fixed by welding or the like. The locking claw 3c has a much smaller cross-sectional area than the main body 3a and is easily elastically deformed. Conversely, the cross-sectional area of the main body 3a is much larger than the cross-sectional area of the locking claw 3c. When the main body 3a is inserted into the bolt / nut, the locking claw 3c bends toward the main body 3a and allows the main body 3a to be inserted into the bolt / nut. On the other hand, after the main body portion 3a is inserted into the bolt and nut, the main body portion 3a is restored and hooked on the thread valley portion on the inner peripheral surface of the nut 2, thereby preventing the main body portion 3a from coming off from the bolt and nut.

  As shown in FIG. 1, the overall length of the lock / key member 3 of this embodiment is considerably longer than the lateral width of the nut. Specifically, it is at least 10% longer than the total length of the communication hole penetrating the bolt and nut. This is to prevent the operator from forgetting to attach the lock / key member 3 by projecting long on purpose. Further, since it can be easily confirmed visually from a distance whether the nut is correctly attached without loosening, maintenance can be omitted. In addition, in the case of a black boxed structure, the message to the good-willed outsider is “You must not release this nut. If there is a problem, let the manager know.”

  Next, a method of using the bolt / nut locking structure will be described. The following operations are performed when the bolts and nuts are used to prevent loosening and when the loosening prevention is released.

  As shown in FIG. 9, as a first step, when the tightening operation of the nut 2 reaches near the limit of tightening, the direction of the split groove 1 b of the bolt 1 is determined by looking at the head 1 ′ side of the bolt 1. 2 is made to coincide with the notch 2c formed on the front end surface of the nut 2, and the rotation of the nut 2 is stopped there. Since the positional relationship between the notch 2c on the front end surface of the nut 2 and the relatively deep groove 2b provided on the rear end surface is synchronized, the deep groove 2b provided on the rear end surface of the nut 2 and the split groove 1b provided on the bolt 1 Are connected, and a communication hole is formed through the bolt and nut. Here, the direction of the groove | channel of both the volt | bolt 1 and the nut 2 does not necessarily correspond in the position where the nut stopped. In this case, after the nut 2 is tightened to the limit for confirmation, the notch groove 2c disposed in the notch groove 2c of the nut 2 is located closest to the direction of the split groove 1b of the bolt 1. The nut 2 is tightened and rotated until the both grooves are aligned.

  As shown in FIG. 10, the lock / key member 3 is attached as a second step. At this time, a through hole that is convenient for work is selected from one through hole that is configured horizontally with the rear end face of the nut 2 or several depending on the layout design of the groove. Then, the lock / key member 3 is inserted until the locking claw 3c operates. This completes the bolt / nut loosening prevention operation.

  FIG. 11 shows the relationship between the restored locking claw 3 c and the nut 2. There is a thread valley on the inner periphery of the nut 2, and when the lock / key member 3 is pulled out, the tip 5 of the locking claw 3c bites into the thread valley. That is, when the lock / key member 3 is to be pulled out, the locking claw 3c is caught in the valley of the screw, and the locking claw 3c is prevented from warping. Therefore, once the locking claw 3c is activated, the lock / key member 3 cannot be pulled out easily.

  When the bolts and nuts once loosened are released later, a plate-shaped jig such as a general-purpose screwdriver is inserted into the split groove 1b opened in the head 1 'of the bolt 1 and provided on the lock key member 3. The lock key member 3 can be easily removed by pulling out the lock key member while pressing the locking claw 3c (pressing it down to the broken line in the figure).

  As a third stage, when tightening at the time of maintenance, after releasing the lock / key member 3 as described above, the rotation of the nut 2 is stopped with the necessary rotation stroke length, and the lock / key member 3 is again turned on. Can be locked. At this time, when the angle of the notch groove 2c formed on the front end face of the nut 2 is read, for example, if the screw pitch is 1.5 mm and the notch groove 2c is advanced by 60 degrees, it is tightened by 0.25 mm. And figure out.

  FIG. 12 shows another example of the bolt 1. The bolt 1 of the above embodiment is a split groove type bolt, whereas the bolt 1 is a horizontal hole type bolt 1. That is, the through-hole 1e is provided in the side surface of the bolt 1 instead of the split groove opening on the head side of the bolt 1. A relatively shallow cutout groove 1d for indicating the direction of the through hole 1e is formed in the top portion 1a of the bolt 1 so as to be synchronized with the direction of the through hole 1e. The length of the long side of the through-hole 1e in the bolt axis direction may be as long as the lock / key member 3 sits and the length required for retightening. Therefore, the strength of the bolt 1 does not decrease so much as in the split groove method.

  The advantage in this case is that an outsider who does not know the structural principle of the bolt and nut cannot easily understand it by just looking at the method of removing the lock / key member 3. Even if you see it, you can't release it without a special jig. Therefore, a so-called lock effect can be expected. On the other hand, since the manufacturing cost is high and the lock / key member 3 cannot be seen from the head 1 ′ of the bolt 1, when the lock / key member 3 is removed, as shown in FIG. Therefore, the locking claw 3c has to be pushed down by inserting a dedicated thin jig-shaped extraction tool 6 such as a metal plate along the main body 3a of the lock / key member 3. The use of the bolt 1 is promising for a more reliable sealing of the structure to be made into a black box, and an application for protecting the structure from being demolished from mischief and malicious persons.

  14 and 15 show another example of the nut. The nut of the above embodiment is a general-purpose (JIS standard) nut with a partial processing, whereas the nut 2 in this example is a round nut with the corners of the nut 2 cut off. 2 is used to add grooving. Except for the point that the nut 2 is cylindrical, it is the same as the nut of the above-described embodiment, and therefore, the same reference numerals are given and description thereof is omitted. According to the nut 2 of this example, the number of grooves 2b on the back surface side of the nut can be increased, and a general spanner can not be used, and the sealing effect can be further enhanced. On the other hand, it is necessary to deepen the notch groove 2c on the front side of the nut 2 and apply a dedicated fastening jig 7 shown in FIG. Man-hours are required for the work as much as dedicated tools are required. The exclusive fastening jig 7 is provided on a cylindrical main body portion 7b, an inner periphery of the main body portion 7b, teeth 7a meshing with the notch groove 2c of the nut 2, a handle 7c for rotating the main body portion 7b, Is provided.

  FIG. 17 shows still another example of the nut 2. In the nut 2 of this example, instead of providing a groove on the back surface (clamping surface) of the nut 2, a through hole 2 e into which the lock / key member 3 is inserted is provided on the side surface of the nut 2. Then, a notch groove 2c synchronized with the through hole 2e is formed on the surface of the nut 2 on the viewing side.

  18 and 19 show another example of the lock / key member 3. The length of the lock key member 3 in this example is substantially the same as the total length of the communication hole penetrating the bolt and nut. By doing so, the location of the lock / key member 3 cannot be confirmed from the head side of the bolt 1. Therefore, the nut 2 is more difficult to be released from a mischief or a malicious person. However, it becomes difficult to insert the lock / key member, and the number of work steps increases.

  FIG. 20 shows an example in which the bolt / nut locking structure of this embodiment is used in combination with a washer 8. For example, when several years have passed when tightening timber, the wood dries and the bolts and nuts loosen, which requires additional tightening. Since the delicate angle of the nut 2 can be adjusted and the inside can be sealed, the bolt / nut loosening prevention structure of the present embodiment is optimal for retightening.

  Taking advantage of the features that can be easily attached and detached, it can be optimally provided for applications that require additional tightening by performing maintenance, such as when the object to be tightened deforms or shrinks over time and a so-called escape phenomenon occurs. .

  Unlike the bolts and nuts that have been used in the past, the bolts and nuts of the present invention are based on an absolute nut whose sealing principle is derived from the mechanical structure. Since it is a rotation stopper, it can also be provided as a holding-side nut when using a double nut as a measure against a place where the nut is likely to loosen due to severe vibration such as an engine installation part of a vehicle, ship, machine tool, etc.

  By utilizing the locking function of the lock / key member of the present invention, this is difficult despite the need for maintenance such as outdoor steel towers and bridges, and it is easy to protect the bolts and nuts from mischief and malicious persons. It can also be used as a lock, or as a lock used when a certain type of structure is to be used as a black box except for a specific person.

  In the grooved nut of this embodiment, the corner of the nut is dropped and tailored into a cylindrical shape, and the nut of this embodiment can be rotated only with a dedicated tightening tool that uses a radial groove provided at the front of the nut. Since a general-purpose tool such as a spanner cannot be used, in this case, it can be optimally provided for applications where it is desired to prevent mischief or removal of a bolt or nut by a malicious person.

  As an application of the function that can easily grasp the tightening amount of the nut, in the fluid flow control device used in various internal combustion engines, chemical plants, etc., the opening of the flow control valve linked to the bolt can be adjusted by turning the nut. It can also be provided for use as a mechanical component for operating a mechanical device, for example, when determining by the amount of protrusion.

It is a perspective view of the bolt and nut loosening prevention structure in one embodiment of the present invention. It is a perspective view of a bolt. It is a perspective view of the volt | bolt in which the lock key member was inserted. It is a perspective view of a nut. It is a front view of a nut. It is sectional drawing of a nut. It is a perspective view of the nut of another example. It is a perspective view of a lock key member. It is a front view which shows the relationship between a nut and a bolt when tightened. It is a front view of the bolt nut which inserted the lock key member. It is sectional drawing of the volt | bolt nut which inserted the lock key member. It is a perspective view which shows the other example of a volt | bolt. It is sectional drawing which shows the state which inserted the exclusive extraction jig | tool and operated the latching claw. It is a perspective view which shows the other example of a nut. It is sectional drawing which shows the other example of a nut. It is a perspective view which shows an exclusive fastening jig | tool. It is a perspective view which shows the other example of a nut. It is a perspective view of the bolt nut which inserted the lock key member of other examples. It is sectional drawing of the nut which inserted the lock key member of the other example. It is a perspective view which shows the example which used the bolt and nut loosening prevention structure of the said embodiment in combination with the washer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bolt 1 '... Head 1a ... Top 1b ... Groove 1d ... Notch groove 1e ... Through hole 2, 4 ... Nut 2a ... Cylindrical part 2b ... Groove 2c ... Notch groove 2e ... Through hole 3 ... Lock key 3a ... Main body 3b ... Stopper 3c ... Locking claw 5 ... End of locking claw 6 ... Exclusive removal jig 7 ... Exclusive fastening jig 7a ... Meshing teeth 7b ... Main body 7c ... Handle 8 ... Washer

Claims (11)

Bolts with one or more grooves or through holes extending in the direction perpendicular to the axis formed on the head and nuts formed with one or more grooves extending in the direction orthogonal to the axis on one seat surface, or Bolts and nuts that appear when a nut with one or more through-holes extending in the direction perpendicular to the axis is formed on the side, and the direction of the groove or through-hole of the bolt and the direction of the groove or through-hole of the nut are synchronized A lock key member that is inserted into a communication hole that passes through the nut and prevents the nut from loosening, and a bolt / nut loosening prevention structure comprising:
The lock key member includes a main body portion inserted into the communication hole penetrating the bolt and nut, a stopper that contacts an outer edge of the nut and stops insertion of the main body portion into the communication hole, and the main body A locking claw provided on the part,
The locking claw is elastically deformed when the main body portion is inserted into the communication hole, and the posture is restored after the main body portion is inserted into the communication hole and reaches a predetermined position, so that the main body portion is connected to the communication hole. Bolt / nut loosening prevention structure characterized by preventing coming out of hole.   2. The bolt provided with one or more through-holes extending in a direction perpendicular to the axis thereof, wherein a notch groove synchronized with the direction of the through-hole is formed in the top of the bolt. The bolt / nut locking structure described.   A nut in which one or more grooves extending in a direction perpendicular to the axis are formed on one seat surface, or a nut in which one or more through-holes extending in a direction orthogonal to the axis are formed on the side surface, the other of the nuts The bolt / nut loosening prevention structure according to claim 1 or 2, wherein a notch groove synchronized with the direction of the groove or the through-hole is formed in the seat surface.   The locking claw of the lock / key member engages with a thread valley portion on an inner peripheral surface of the nut to prevent the main body portion from coming off from the communication hole penetrating the bolt / nut. The bolt / nut locking structure according to any one of claims 1 to 3.   5. The loosening of the bolt and nut according to claim 1, wherein a total length of the lock key member is at least 10% longer than a total length of the communication hole penetrating the bolt and nut. Stop structure.   The bolt / nut locking structure according to any one of claims 1 to 4, wherein an overall length of the lock / key member substantially coincides with an overall length of the communication hole penetrating the bolt / nut.   The bolt / nut locking structure according to any one of claims 1 to 6, wherein the nut is a square nut.   The bolt / nut locking structure according to any one of claims 1 to 6, wherein the nut is a round nut.   The bolt / nut locking structure according to any one of claims 1 to 6, wherein the nut is a nut having a square part and a round part.   The bolt / nut locking structure according to any one of claims 1 to 9, wherein a cross-sectional area of the main body of the lock / key member is significantly larger than a cross-sectional area of the locking claw.   The bolt / nut locking structure according to any one of claims 1 to 10, wherein a cross-sectional shape of the main body of the lock / key member is a square shape or a substantially square shape.

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