JP2012017832A - Fastening structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fastening structure that can surely perform a function for avoiding theft.SOLUTION: A nut (11) is composed of a conical base (11A) and an angular portion (11B), a recessed groove (11C) is formed between the conical base and the angular portion, insertion holes are protrusively formed at the conical base and the angular portion, a female thread is formed at least at a portion of the conical base of the insertion holes, on the other hand, a bolt head (10A) is formed into a spherical shape, a male screw (10B) of a bolt shaft is screwed into at least the female thread of the conical base, the angular portion of the nut is rotated, members (13, 14) to be fastened are fastened between the bolt head and the conical base of the nut, and the angular portion of the nut is fractured from the recessed groove.

Description

  The present invention relates to a fastening structure, and more particularly to a structure that reliably functions to prevent theft.

  Bolts and nuts are often used for fastening in various fields such as steel towers and bridges. Normally, with bolts and nuts, the bolt shaft is inserted into the insertion hole of the member to be fastened, the female screw of the nut is screwed into the male screw of the bolt, and a plurality of fastened members are tightened between the bolt head and the nut. However, if the bolt or nut is intentionally turned with an excessive force, the bolt or nut can be turned in the loosening direction to release the fastening.

  On the other hand, a fastening structure has been proposed in which after a nut is screwed onto a bolt shaft portion, an idle cover is rotatably fitted around the nut so that the nut cannot be turned (Patent Document 1).

  In addition, after screwing the nut into the bolt shaft part, the idle ring is rotatably fitted around the lock nut body, and an operation part that can be operated by a tool is integrally formed on the body. There has been proposed a fastening structure in which a lock nut is screwed into rotation and pressed against the nut, and then an operation portion of the lock nut is broken from the main body so that the lock nut cannot be turned (Patent Document 2). ).

JP 2001-241424 A JP 2000-240632 A

  However, in the fastening structures described in Patent Documents 1 and 2, the nut side cannot be operated with a tool, but since the hexagonal bolt head remains, the tool is fitted to the bolt head and rotated with a strong force. Then, the bolt can be turned in the loosening direction by the friction of the washer, and the fastening can be removed.

  In view of such problems, an object of the present invention is to provide a fastening structure that reliably performs a function of avoiding theft.

  Therefore, the fastening structure according to the present invention is a fastening structure in which a fastened member is fastened and fastened between a bolt head and a nut, and the nut includes a truncated cone part and a square part, and the truncated cone A concave groove is formed between the portion and the angular portion, an insertion hole is formed in the truncated cone portion and the angular portion, and an internal thread is formed in at least the truncated cone portion of the insertion hole. On the other hand, the bolt head has a spherical shape, the male screw of the bolt shaft portion is screwed with at least the female screw of the truncated cone portion, and the square portion of the nut is rotated to rotate the bolt head and the truncated cone of the nut. A member to be fastened is fastened with the portion, and the angular portion of the nut is broken from the groove when the rotational operation force of the nut reaches a predetermined torque.

  One of the features of the present invention is that when the square member of the nut is rotated to fasten the fastened member between the bolt head and the truncated cone portion of the nut, and the rotational operation force of the nut reaches a predetermined torque In addition, the square portion of the nut is broken from the groove.

  As a result, the bolt axial force depends on the breaking torque of the nut square part, and a stable bolt axial force can be obtained by controlling the breaking torque to be constant, and it is fastened due to vibration, thermal expansion, changes over time, etc. The risk of loosening can be reduced.

  When the angular part of the nut is broken from the groove, the truncated cone part of the nut and the spherical bolt head remain, and it is practically difficult to reversely rotate the nut and bolt, and the effect of avoiding theft Can guarantee.

  If the nut's square part is broken from the groove, the bolt shaft part will be exposed from the truncated cone part of the nut, and if this is gripped with a suitable tool and turned strongly, the fastening may loosen, If the seat surface or washer on the nut side is smaller than the seat surface or washer on the bolt head side, the bolt shaft portion cannot be turned in the loosening direction, and there is no possibility that the fastening will come off, and the effect of avoiding theft can be ensured.

  The fastening structure according to the present invention is a fastening structure in which a fastened member is fastened and fastened between a bolt head and a nut. The nut has a truncated cone shape, and an insertion hole is formed in the nut. On the other hand, the female head is formed, while the bolt head has a spherical shape, and the bolt head is integrally formed with a rotation operation part through a concave groove. The male screw on the bolt shaft is screwed with the female screw on the nut. The rotation operation part of the bolt is rotated, the fastened member is fastened between the bolt head and the nut, and the rotation operation part is recessed when the rotation operation force of the rotation operation part reaches a predetermined torque. It is characterized by being broken from the groove.

  A feature of the present invention is that a rotary operation part is formed on the spherical bolt head through a concave groove, the rotation operation part of the bolt is rotated to fasten the fastened member between the bolt head and the nut, It is in the point which made the rotation operation part fracture | rupture from a ditch | groove.

  As a result, the bolt axial force depends on the breaking torque of the rotary operation part, and a stable bolt axial force can be obtained by controlling the breaking torque to be constant, and the fastening can be performed due to vibration, thermal expansion, aging, etc. The risk of loosening can be reduced.

  If the rotation operation part of the bolt is broken, a truncated cone-shaped nut and a spherical bolt head remain, so that it is practically difficult to reversely rotate the nut and bolt, and the effect of avoiding theft can be guaranteed. .

  Although the rotation operation portion may be square, for example, if it is subjected to a selection process, it has the same structure as a pin tail portion of a known Torcia bolt, so that the breaking torque can be easily controlled.

It is a side view which shows preferable embodiment of the fastening structure which concerns on this invention. It is sectional drawing in the said embodiment. It is a side view which shows the state which fractured | ruptured the square part of the nut at the time of fastening in the said embodiment. It is a side view which shows 2nd Embodiment. It is sectional drawing in the said embodiment. It is a side view which shows the state which fractured | ruptured the rotation operation part of the bolt head at the time of fastening in the said embodiment.

  Hereinafter, the present invention will be described based on specific examples shown in the accompanying drawings. 1 to 3 show a preferred embodiment of a fastening structure according to the present invention. In the figure, the nut 11 is composed of a truncated cone portion 11A and a hexagonal portion 11B. A concave groove 11C is formed annularly between the truncated cone portion 11A and the hexagonal portion 11B, and the truncated cone portion 11A and the hexagonal portion 11B. The hexagonal portion 11B has an insertion hole extending in the axial direction, and a female screw is formed in the insertion hole of the truncated cone portion 11A. However, no female screw is formed in the insertion hole of the hexagonal portion 11B. Remains.

  The bolt 10 includes a head portion 10A and shaft portions 10B and 10C. The bolt head portion 10A is formed in a spherical shape, and the bolt shaft portion 10B is formed with a male screw up to a position where it is screwed with the female screw of the truncated cone portion 11A. The bolt shaft portion 10C is not formed with a male screw and remains a shaft.

  For example, when fastening the fastened members 13 and 14, as shown in FIGS. 1 and 2, the bolt shaft portions 10B and 10C of the bolt 10 are inserted into the insertion holes of the fastened members 14 and 13 through the washers 12B. Then, after screwing onto the female thread of the truncated cone portion 11A of the nut 11 placed on the side of the fastened member 13 via the washer 12A having a diameter smaller than that of the washer 12B, a tool is fitted into the hexagonal portion 11B of the nut 11 When the nut 11 is tightened to some extent, the square portion of the nut 11 is strongly tightened, the reaction force of the rotation of the nut 11 is received by the washers 12A and 12B, and the fastened members 13 and 14 are connected to the bolt head 10A and the nut. Tighten with the 11 truncated cone portions 11A.

  When the angular portion 11B of the nut 11 is further rotated and the torque reaches a predetermined value, the angular portion 11B of the nut 11 is broken from the concave groove 11C as shown in FIG. The breaking torque can be set by the material of the nut 11 and the outer diameter of the concave groove 11C, and can be broken with a constant torque.

  Then, since the axial force of the bolt shaft portion 10B is determined depending on the breaking torque of the rectangular portion 11B of the nut 11, a stable bolt axial force can be obtained.

  When the rectangular portion 11B of the nut 11 is broken, the truncated cone portion 11A of the nut 11 and the spherical bolt head portion 10A remain, and it is substantially difficult and reliable to reversely operate the nut 11 and the bolt 10. Can avoid theft.

  Note that when the rectangular portion 11B of the nut 11 is broken from the concave groove 11C, the bolt shaft portion 10C is exposed from the truncated cone portion 11A of the nut 11. If this is gripped with an appropriate tool and turned strongly, the fastening may be loosened.

  However, since the nut-side washer 12A has a smaller diameter than the bolt head-side washer 12B, the bolt shaft portion 10C cannot be rotated in a loosening direction, and there is no possibility that the fastening is released.

  4 to 6 show a second embodiment, and the same reference numerals as those in FIGS. 1 to 3 denote the same or corresponding parts. In this example, the selection portion 10D is integrally formed on the head portion 10A of the bolt 10 via the concave groove 10E, while the nut 11 is formed in a truncated cone shape.

  When fastening the to-be-fastened members 13 and 14, after assembling the bolt 10 and the nut 11 as in the first embodiment, the tool is fitted into the selection portion 10D of the bolt 10, and the selection portion 10D is rotated to select the selection portion 10D. Is received by the washer 12, and the fastened members 13 and 14 are tightened between the bolt head 10 </ b> A and the nut 11.

  When the selection portion 10D of the bolt 10 is further rotated and the torque reaches a predetermined value, the selection portion 10D is broken from the concave groove 10E as shown in FIG. The breaking torque can be set by the material of the selection portion 10D and the outer diameter of the concave groove 10E, and can be broken with a constant torque, so that a stable bolt axial force can be obtained.

  Further, when the selection portion 10D of the bolt 10 is broken, the truncated cone-shaped nut 11 and the spherical bolt head portion 10A remain, and it is substantially difficult to reversely rotate the nut 11 and the bolt 10; The effect of avoiding theft can be guaranteed.

10 bolt 10A head 10B, 10C bolt shaft 10D selection part (rotation operation part)
10E Concave groove 11 Nut 11A Frustum part 11B Hexagon part 11C Concave groove

Claims (3)

In the fastening structure that tightens and tightens the fastened member between the bolt head and the nut,
The nut (11) is composed of a truncated cone part (11A) and an angular part (11B), and a concave groove (11C) is formed between the truncated cone part (11A) and the angular part (11B). The truncated cone part (11A) and the angular part (11B) are provided with insertion holes, and at least a part of the truncated cone part (11A) of the insertion hole is formed with a female screw,
The bolt head (10A) has a spherical shape, and the male screw (10B) of the bolt shaft portion is screwed with at least the female screw of the truncated cone portion (11A),
The square member (11B) of the nut (11) is rotated to fasten the fastened members (13, 14) between the bolt head (10A) and the truncated cone part (11A) of the nut (11). A fastening structure, wherein the angular portion (11B) of the nut (11) is broken from the concave groove (11C) when the rotational operation force of (11) reaches a predetermined torque. In the fastening structure that tightens and tightens the fastened member between the bolt head and the nut,
The nut (11) has a truncated cone shape, and the nut (11) is formed with an insertion hole to form a female screw, while the bolt head (10A) has a spherical shape, and the bolt head (10A) , The rotary operation part (10D) is integrally formed through the concave groove (10E), and the male screw (10B) of the bolt shaft part is screwed with the female screw of the nut (11).
The rotation operation part (10D) of the bolt (10) is rotated to fasten the fastened members (13, 14) between the bolt head (10A) and the nut (11), and the rotation operation part (10D) rotates. A fastening structure characterized in that when the operating force reaches a predetermined torque, the rotation operation portion (10D) is broken from the concave groove (10E). The fastening structure according to claim 1 or 2, wherein the rotation operation portion (10D) is subjected to a selection process.

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