JP7665488B2 - Anti-loosening structure - Google Patents

Description

The present invention relates to a structure for preventing loosening of a fastening part using a threaded steel rod and a nut.

It is well known that disc springs are used to prevent nuts and bolts (screws) from loosening in connections in wooden buildings, power mains, and other fastenings (see Patent Documents 1 and 2).

Patent Document 1 describes, "A washer characterized in that a spring member which expands and contracts in the axial direction of a bolt through hole provided in a washer body is disposed in the washer body, and the spring member and the washer body are integrated by anti-fall-out means which prevents the spring member from falling off from the washer body." (Claim 1).
Furthermore, "In the present invention thus configured, leaf springs 12e, 12b... which expand and contract in the axial direction of bolt through hole 11b provided in washer body 11a are disposed across the upper opening end of bolt through hole 11b and the upper surface of washer body 11a in the vicinity thereof, and a frame body 12d which rises from washer body 11a along the axial direction of bolt through hole 11b and surrounds the periphery of leaf springs 12e, 12b... is fixed to washer body 11a. Then, by providing hook portion 124a at tip end 124b of frame body 12d and using frame body 12d which has a hook-shaped cross section, leaf springs 12e, 12b... are held within frame body 12d, and washer body 11a and leaf springs 12e, 12b... are integrated, thereby making it possible to reduce the number of parts used for joining." (paragraph [0058] ), "In the present invention, the anchor bolt 13 protruding from the foundation 20 is inserted into the bolt insertion hole 33a provided in the wooden base 33 of the wall panel 31 of the building unit 30, the bolt through hole 11b of the washer body 11a, and the bolt through holes 126, 127 of each of the leaf springs 12e, 12b, and the washer 11 is attached to the portion of the base 33 from which the bolt 13 protrudes (around the bolt insertion hole 33a). Then, the nut 14 is screwed onto the bolt 13. Even if the wooden base 33 shrinks, the multiple leaf springs 12e, 12b, ... interposed between the nut 14 and the washer body 11a will restore to their original state so as to follow the wood shrinkage and extend between the nut and the washer, thereby preventing loosening of the joint due to wood shrinkage." (Paragraph [0063])

Patent Document 2 describes "an anti-loosening screw fastener comprising the nut according to claim 1 or 2, a bolt which is passed through a fastened member, a plate-shaped fastening member having a hole whose inner diameter is larger than the outer diameter of the tip of the tapered portion and which has a diameter smaller than that of the large diameter portion, and a spring made of elastic metal which has a hole whose diameter is larger than that of the large diameter end of the sleeve-shaped nut portion and which acts in the axial direction of the bolt, wherein the sleeve-shaped nut portion is guided into the hole of the fastening member and the hole of the spring, and the inner peripheral portion of the hole of the fastening member is in contact with the tapered portion, and the nut is screwed onto the bolt from the sleeve-shaped nut portion side." (Claim 3)
The document also states that "5 is a flat washer made of the same material as the nut 1, and has a standing wall 50 formed on the outer periphery for the convenience of setting the spring 4, tightening member 3, spacer ring 2, etc., in the fastening portion of the fastened members 7, 70 as described below." (Paragraph [0018]), and "As shown in FIG. 1, a bolt 6 with a shaft 60 length of 60 mm and a thread pitch of 1.5 mm is inserted into the overlapping portion of the fastened members 7, 70 via a washer 62 on the head 61 side, and a flat washer 5, spring 4, tightening member 3, and spacer ring 2 are set, in that order, on the surface from which the shaft 60 protrudes. Next, the nut 10 is screwed onto the shaft 60 of the bolt 6 from the sleeve-shaped nut portion 11 side until the dish-shaped spring 4 is deformed flat as shown in FIG. 2, and the spacer ring 2 is pressed against the underside of the flange-shaped nut portion 10 and cannot be turned (to the limit)." (Paragraph [0020]).

It is also known that in vibration control structures for buildings, multiple disc springs are used at joints made with high-strength bolts (see Patent Document 3).

Patent Document 3 describes a vibration control structure for a building, characterized in that "at a joint of a building joined with a high-strength bolt, a sliding plate is provided on one of the two joined members, and a friction plate is provided on the other member so that it can slide freely on the sliding plate, and a biasing means is provided at the overlapping portion of the sliding plate and the friction plate for pressing them in a direction in which they are pressed against each other to form a friction damper, and the biasing means uses a disc spring that is deflected and deformed within a nonlinear spring region in which the variation in elastic force relative to the amount of deflection variation is small when a set pressure is applied, and a friction material is interposed on the contact surface between the friction plate and the sliding plate of the friction damper" (Claim 1).
In addition, "... the high-strength bolt 32 is inserted into the disc spring set 28a so that it is sandwiched between a washer 34 and a collar 35a arranged on the bolt head 32a side, and a collar 35b arranged on the friction plate 22 side, and a guide ring 38 is fitted into the inner periphery of the disc spring set 28a to maintain concentricity with the high-strength bolt 32. A washer 34 is also arranged on the nut 36 side, and by tightening the high-strength bolt 32 and the nut 36 in this state, the disc spring "The spring force of the disc spring set 28a generated by this tightening acts between the friction plate 22 and the sliding plate 24 as the axial force of the high strength bolt 32, and generates a predetermined friction force while pressing the friction material 37 interposed between them. As shown in FIG. 6(b), the guide ring 38 may be formed integrally with the washer 34." (paragraph [0061])

JP 2007-308946 A Japanese Unexamined Patent Publication No. 7-151129 JP 2000-34847 A

The technology of using disc springs to prevent loosening of the fixed part formed by the nut and bolt (threaded steel rod) is publicly known (see Patent Documents 1 and 2). However, when multiple disc springs are used, particularly when the number of disc springs is large, there is a problem that the radial positions of the multiple disc springs vary with only an outer guide (a frame surrounding the periphery as described in Patent Document 1, and a standing wall on the outer periphery as described in Patent Document 2), making it difficult to use the repulsive force of the disc springs to push up the nut and prevent it from loosening.
The technology disclosed in Patent Document 3 uses a disc spring, but the disc spring is not used to prevent loosening of the fixed portion formed by the nut and bolt.

The objective of the present invention is to provide a locking structure that can reliably prevent loosening of the fastening parts formed by the nut and threaded steel rod.

In order to solve the above problems, the present invention employs the following means.
(1) An anti-loosening structure comprising a nut, a threaded steel rod screwed into the nut, an inner guide having a large diameter portion arranged in contact with the underside of the nut and with the threaded steel rod passing through its center and a small diameter portion extending downward from the large diameter portion to surround the threaded steel rod, an anchor plate arranged below the inner guide and through which the threaded steel rod and inner guide pass, an outer guide erected upward from the anchor plate and surrounding the threaded steel rod and inner guide, and a group of disc springs fitted between the inner guide and the outer guide, with the threaded steel rod and inner guide passing through their centers.
(2) The anti-loosening structure according to claim 1, wherein the large diameter portion has an upper surface that contacts the lower surface of the nut and a lower surface that contacts the upper surface of the group of disc springs, and when the group of disc springs is compressed, the outer periphery of the lower surface that contacts the upper surface of the group of disc springs comes into contact with the upper surface of the outer guide, thereby preventing damage to the group of disc springs.

In the present invention, by using an anti-loosening structure with a group of disc springs fitted between the inner and outer guides, even if wood shrinkage occurs in a wooden building, the disc springs will restore to their original state to accommodate it, preventing the radial positions of the multiple disc springs from varying, and extending between the nut and anchor plate, it is possible to reliably prevent loosening of the fixed part formed by the nut and threaded steel rod.

FIG. 1 is a cross-sectional view showing a loosening prevention structure according to one embodiment of the present invention. FIG. 2 is a photograph showing the appearance of an anti-loosening structure according to one embodiment of the present invention, in which (a) is a perspective photograph of the appearance as seen from the nut 1 side, and (b) is a perspective photograph of the appearance as seen from the anchor plate (anchor) 5 side.

One embodiment of the present invention (hereinafter referred to as "this embodiment") will be described with reference to FIG. 1.

As shown in FIG. 1, this embodiment is an anti-loosening structure that includes a nut 1, a threaded steel rod 2 that screws into the nut 1, an inner guide 3 with a large diameter portion 4A that is arranged in contact with the underside of the nut 1 and with the threaded steel rod 2 penetrating through the center and a small diameter portion 4B that extends downward from the large diameter portion 4A to surround the threaded steel rod 2, an anchor plate 5 that is arranged below the inner guide 3 and through which the threaded steel rod 2 and inner guide 3 pass, an outer guide 6 that stands upright from the anchor plate 5 and surrounds the threaded steel rod 2 and inner guide 3, and a group of disc springs 7 (multiple disc springs) that are fitted between the inner guide 3 and the outer guide 6 and through which the threaded steel rod 2 and inner guide 3 pass through the center.

(Nut 1)
As shown in FIG. 2, the nut 1 may be a hexagonal nut.
The dimensions of the nut 1 can be set appropriately, but in this embodiment, the diagonal distance is 53 mm and the height is 55 mm.
The material that can be used is S45C (JIS G 4051: carbon steel material for machine structures having a carbon content of 0.42 to 0.48 mass%) drawn material or an equivalent material.
The inner surface of the nut 1 is provided with a threaded portion that screws into the outer surface (threaded portion) of the threaded steel rod 2 described later.

(Threaded steel rod 2)
In this embodiment, the threaded steel bar 2 is a fully threaded PC steel bar as specified in the deformed steel bar of JIS G 3109, which is a steel bar with threaded knots formed along its entire length by hot rolling and then subjected to high-frequency heat treatment. This threaded steel bar has the advantage that it can be cut to the required length at the construction site and used because it has a threaded shape along its entire length, and has excellent adhesive strength with concrete. In addition, various threaded steel bars (bolts) that are normally used in wooden buildings, etc. can also be used.
The impurities of the threaded steel bar 2 can be within the ranges specified in JIS G 3109 (PC steel bar), that is, P is 0.030 mass% or less, S is 0.035 mass% or less, and Cu is 0.30 mass% or less.
The dimensions of the threaded steel rod 2 can be set as appropriate, but in this embodiment, the diameter (outer diameter) is 25 mm. The length of the threaded steel rod 2 in the longitudinal direction can be set as appropriate depending on the application, but it has a length that penetrates the nut 1, the inner guide 3, and the anchor plate 5, and protrudes outward from the nut 1 and also from the inner guide 3.
Regarding the properties of the threaded steel bar 2, a proof stress of 930 N/ ^mm2 or more or 1080 N/ ^mm2 or more can be used. A tensile strength of 1080 N/ ^mm2 or more or 1230 N/ ^mm2 or more can be used. An elongation of 5% or more can be used. A maximum tensile load of 411 kN or more to 1253 kN or more can be used depending on the diameter.

(Inner guide 3)
The inner guide 3 can be a tubular body that is disposed in contact with the underside of the nut 1 , has the threaded steel rod 2 penetrating its center, and extends downward to surround the threaded steel rod 2 .
More specifically, the inner guide 3 has a large diameter portion 4A and a small diameter portion 4B.
The dimensions of the inner guide 3 can be set as appropriate, but in this embodiment, the large diameter portion 4A has an outer diameter of 90 mm, an inner diameter of 26 mm, and a thickness of 14 mm, while the small diameter portion 4B has an outer diameter of 32 mm, an inner diameter of 26 mm, and a length of 280 mm.
The material may be SPCC (JIS G 3141: cold-rolled steel plate with a carbon content of 0.15 mass% or less) or SS400 (JIS G 3101: hot-rolled structural steel with P of 0.05 mass% or less and S of 0.05 mass% or less). The surface may be unichrome plated (electrogalvanized material is chromated with a solution containing fluoride).

(Anchor plate 5)
The anchor plate 5 can be a square plate disposed under the inner guide 3 and having a through hole 5a through which the threaded steel rod 2 and the inner guide 3 pass.
The dimensions of the anchor plate 5 can be set appropriately, but in this embodiment, the two-face width is 120 mm, the thickness is 25 mm, and the hole diameter (inner diameter) of the through hole 5a is 33 mm.
The material used may be S400 or higher or an equivalent material.

(Outer guide 6)
The outer guide 6 is a tubular body standing upward from the anchor plate 5, and surrounds the threaded steel rod 2 and the inner guide 3. In this embodiment, the anchor plate 5 and the outer guide 6 are joined by welding. Note that the anchor plate 5 and the outer guide 6 may be integrally formed.
The dimensions of the outer guide 6 can be set appropriately, but in this embodiment, the outer diameter is 95 mm, the inner diameter is 75 mm, the thickness is 10 mm, and the length is 130 mm.
The material may be STKM (JIS G 3445: carbon steel pipe for machine structure). The pipe may be unichrome plated.

(Disc spring group 7)
The disc spring group (plurality of disc springs) 7 is made up of multiple stacked disc-shaped springs, each having a through hole 7a in the center through which the threaded steel rod 2 and the inner guide 3 pass, and is fitted between the inner guide 3 and the outer guide 6, with its dimensions appropriately set. In this embodiment, the outer diameter is 71 mm, the inner diameter is 36 mm, the thickness is 4 mm, and the deflection is 1.6 mm.
The material may be Ni-plated SUS or the like.
The number of disc springs 7 is appropriately set according to the thickness of the foundation of a wooden building.

As shown in FIG. 1, the stacking state of the disc spring group 7 can be such that two disc springs are tied together, and multiple sets of tied disc springs are provided. Alternatively, multiple disc springs can be stacked in a cap-like shape, and the cap-like stacked disc spring sets can be tied together. By changing the stacking state of the disc springs, the overall allowable deflection amount of the multiple disc springs combined can be changed.

(Assembly of anti-loosening structure)
The anti-loosening structure is assembled, for example, as follows.
A plurality of disc springs are placed on the inner surface of the outer guide 6 of the anchor plate 5 on which the outer guide 6 is erected and stacked to form a disc spring group 7, and then the small diameter portion 4B of the inner guide 3 is penetrated through the central through hole 7a of the disc spring group 7 and the through hole 5a of the anchor plate 5, and the multiple disc springs (disc spring group) 7 are fitted between the small diameter portion 4B of the inner guide 3 and the outer guide 6.

Next, the threaded steel rod 2 is passed through the through hole 3a of the inner guide 3 and the through hole 5a of the anchor plate 5 (through which the small diameter portion 4B of the inner guide 3 passes), and the nut 1 is screwed onto the top of the threaded steel rod 2, completing the anti-loosening structure.
As described above, according to this embodiment, the anti-loosening structure can be easily assembled.

The case where the anti-loosening structure according to this embodiment is applied to the joining of a wooden building will be described.
Here, a wooden building refers to a building in which at least one structural element of the building's framework, for example a base made of concrete and a foundation made of wood, is made.

When the anti-loosening structure according to this embodiment is applied to the joining of wooden buildings, the threaded steel rod 2 protruding from the foundation is inserted into the insertion hole (not shown) of the threaded steel rod 2 provided in the wooden base of the wall panel of the building unit and into the through hole 3a of the inner guide 3 from the bottom of the anchor plate 5, and the nut 1 is screwed onto the top of the threaded steel rod 2 with the anchor plate 5 in contact with the periphery of the insertion hole (through which the inner guide 3 passes) of the threaded steel rod 2 on the base side. As a result, even if the wooden base shrinks, the disc spring group 7 fitted between the small diameter part 4B of the inner guide 3, which is located between the large diameter part 4A of the inner guide 3 that contacts the underside of the nut 1 and the anchor plate 5, and the outer guide 6, will recover to follow the wood shrinkage and extend between the large diameter part 4A of the inner guide 3 and the anchor plate 5. At that time, the disc spring group 7 is fitted between the small diameter portion 4B of the inner guide 3 and the outer guide 6, so that its position is restored without shifting in the radial direction of the threaded steel rod 2, and loosening of the fixed portion between the nut 1 and the threaded steel rod 2 can be reliably prevented.

As shown in Figures 1 and 2, the inner guide 3 is provided with a large diameter portion 4A, the upper surface of which contacts the lower surface of the nut 1 and the lower surface of which contacts the upper surface of the disc spring group 7, and through which the threaded steel rod 2 passes in the center, and a small diameter portion 4B, which is arranged integrally with the large diameter portion 4A, the threaded steel rod 2 passes through the center, extends downward to surround the threaded steel rod 2, passes through the anchor plate 5, is surrounded by the outer guide 6, passes through the center of the disc spring group 7, and fits the disc spring group 7 between the large diameter portion 4A and the outer guide 6. It is preferable that, when the disc spring group 7 is compressed, the outer periphery of the lower surface of the large diameter portion 4A, which contacts the upper surface of the disc spring group 7, contacts the upper surface of the outer guide 6, thereby preventing damage to the disc spring group 7.
By using such an inner guide 3, the number of parts can be reduced and damage to the disc springs 7 due to compression can be prevented.

The anti-loosening structure of the present invention can reliably prevent loosening of the fastening parts formed by the nut 1 and the threaded steel rod 2, making it suitable for use in fastening parts of wooden buildings, etc.

1: Nut 2: Threaded steel rod 3: Inner guide 3a: Through hole of threaded steel rod provided in inner guide 3 4A: Large diameter section 4B: Small diameter section 5: Anchor plate 5a: Through hole of inner guide 4 provided in anchor plate 5 6: Outer guide 7: Disc spring group 7a: Through hole of inner guide 4 provided in disc spring 7

Claims (1)

an inner guide having a large diameter portion arranged in contact with the underside of the nut, with the threaded steel rod passing through its central portion and a small diameter portion extending downward from the large diameter portion to surround the threaded steel rod; an anchor plate arranged below the inner guide and through which the threaded steel rod and the inner guide pass; an outer guide erected upward from the anchor plate and surrounding the threaded steel rod and the inner guide; and a group of disc springs fitted between the inner guide and the outer guide, with the threaded steel rod and inner guide passing through its central portion , wherein the upper surface of the large diameter portion of the inner guide is in contact with the underside of the nut and the lower surface is in contact with the upper surface of the group of disc springs, and when the group of disc springs is compressed, the outer peripheral portion of the lower surface that is in contact with the upper surface of the group of disc springs comes into contact with the upper surface of the outer guide, thereby preventing damage to the group of disc springs .