JP7473921B2 - Engagement bolt - Google Patents

Description

The present invention relates to a bolt with an engagement part that has an engagement part at the tip of the male thread.

Conventionally, this type of bolt with an engagement part is known to have an engagement part at the tip where a spiral vane-shaped spring extending in the axial direction is formed on the outer periphery, and a female member corresponding to this engagement part is engaged to prevent the fastened bolt and nut from loosening (see, for example, Patent Document 1).

In addition, when fastening materials with a bolt and nut, a so-called "one-sided bolt" is known, which allows the bolt and nut temporarily fixed between the fastened materials to be tightened only from one of the fastened materials (see Patent Document 2).

Furthermore, a fiber-reinforced resin walkway, such as that described in Patent Document 3, is known that has a small number of main girder parts and makes it easier to ensure the strength of the main girder.

Japanese Patent Application Laid-Open No. 7-197925 Patent No. 2723493 Patent No. 6915218

There are no conventional bolts with engaging parts that have both the functions of the bolt and nut in Patent Document 1 and the one-sided bolt in Patent Document 2. There is also a demand for a one-sided bolt that is easy to tighten and does not come loose, suitable for fiber-reinforced resin walkways like those in Patent Document 3.

The present invention was made in consideration of these points, and its purpose is to make a fastening bolt that can be prevented from loosening and can be fastened only from one side of the fastened member.

To achieve the above objective, in this invention, a second engagement portion is provided at the tip of the first engagement portion.

Specifically, in the first aspect of the present invention, a bolt head that can be gripped and tightened with a tool,
a rod-shaped bolt body continuous with the bolt head;
A male thread portion at the tip side of the bolt body;
a first engagement portion having anti-loosening protrusions provided at intervals in a circumferential direction at a tip of the male thread portion;
The first engaging portion is further provided with a second engaging portion provided at a tip thereof and having a tool engaging protrusion with which a fastening tool engages.

According to the above configuration, the anti-loosening effect is achieved by engaging the anti-loosening protrusion of the first engagement part with the anti-loosening part of the anti-loosening nut. In addition, by engaging a fastening tool with the tool engagement protrusion from the tip side and rotating it, the male screw can be screwed in and fastened.

In a second aspect of the present invention, in the first aspect,
The circumferential pitch of the locking projections is smaller than the circumferential pitch of the tool engagement projections of the second engagement portion.

According to the above configuration, the anti-loosening effect can be improved by reducing the circumferential pitch of the anti-loosening portion, and the torque of the tool can be easily transmitted by increasing the circumferential pitch of the tool engagement protrusions.

In a third aspect of the present invention, in the first or second aspect of the present invention,
The maximum outer diameter of the first engagement portion is larger than the maximum outer diameter of the second engagement portion,
A step is provided between the first engaging portion and the second engaging portion.

According to the above configuration, by providing a step between the two engagement parts, it is possible to prevent the first engagement part from being damaged by a tool engaged with the second engagement part.

In the fourth invention, the bolt with an engagement portion of any one of the first to third inventions is made of a one-piece molded product made of reinforced fiber resin.

The above configuration allows bolts with relatively high rigidity to be easily formed even with complex shapes. In addition, bolts with engaging parts made of reinforced fiber resin are suitable for fastening resin structures such as walkways made of the same material reinforced resin.

In a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention,
The maximum diameter of the first engagement portion is smaller than the maximum diameter of the male thread portion and larger than the maximum diameter of the second engagement portion.

According to the above configuration, the second engagement part on the tip side is inserted into a locking nut or the like, and the second engagement part is used to tighten the bolt with an engagement part using a tool to engage the first engagement part with a locking part such as a locking nut, thereby tightening from one direction and achieving a locking effect.

In a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention,
The anti-loosening protrusions of the first engagement portion extend in the longitudinal direction of the bolt body and form ridges arranged at equal intervals in the circumferential direction,
The second engagement portion has a polygonal cross section.

With the above configuration, the first engagement part with the ridges provides an anti-loosening effect, while the second engagement part with a polygonal cross section makes it easy to tighten with a tool such as a wrench or pliers.

In a seventh aspect, in the sixth aspect,
The anti-loosening projection of the first engagement portion is an externally toothed ratchet wheel.

The above configuration provides an optimal anti-loosening protrusion that allows rotation in the tightening direction and prevents rotation in the loosening direction.

As explained above, according to the present invention, a second engagement portion for tool engagement is provided beyond the first engagement portion for preventing loosening, so the fastening bolt can be prevented from loosening and can be fastened only from one side of the fastened member.

1 is a front view showing an electric power tool to which a fastening tool for an engagement portion-equipped bolt is fixed. 1 is a side view showing an electric power tool to which a fastening tool for an engagement portion-equipped bolt is fixed. 1A is a left side view of a bolt with an engagement portion, FIG. 1B is a front view of the bolt, and FIG. 1 is a front view showing a state in which the locking nut is fastened to the engagement portion-equipped bolt to prevent loosening. FIG. 13 is a front view showing the locking nut temporarily fastened to the engagement portion-equipped bolt. FIG. 1A is a left side view of a locking nut, FIG. 1B is a front view of the locking nut, and FIG. 1 is a plan view showing a state in which an engagement bolt and a locking nut are attached to a fastening tool for the engagement bolt. FIG.

The following describes an embodiment of the present invention with reference to the drawings.

- Structure of the bolt with engagement part -
3 shows an embodiment of the bolt 1 with an engagement portion according to the present invention, which is an integrally molded product made of reinforced fiber resin, such as a reinforced fiber synthetic resin containing glass fiber, carbon fiber, etc. Examples of synthetic resins include thermoplastic resins such as polyamide resin (PA), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and ABS resin, and thermosetting resins such as epoxy resin and vinyl ester resin. As such, since the bolt 1 with an engagement portion is an integrally molded product made of reinforced fiber resin, it is possible to easily mold a bolt with a relatively high rigidity even if it has a complex shape.

The engaging bolt 1 has, for example, a hexagonal bolt head 2 that can be gripped and tightened with a tool such as a torque wrench. This may also be a hexagonal socket head.

The bolt with engagement portion 1 has a rod-shaped bolt body 3 that is continuous with the bolt head 2, and in this embodiment, this bolt body 3 has a cylindrical portion with no irregularities and a male thread portion 4 at the tip side.

The tip of the male thread portion 4 is provided with a first engagement portion 5 having anti-loosening projections 5a spaced apart in the circumferential direction. The anti-loosening projections 5a extend in the longitudinal direction of the bolt body 3 and form ridges that are spaced apart in the circumferential direction.

As shown in a partially enlarged view in FIG. 3(c), the locking protrusion 5a is composed of an external toothed ratchet wheel with a substantially triangular cross section of the same shape and size. Specifically, the external toothed ratchet wheel has an outer meshing surface 5b included in the same imaginary plane as the axis of the bolt body 3, and an outer tapered surface 5c that is inclined from the tip of the outer meshing surface 5b toward the tightening direction of the locking nut 10 relative to the outer meshing surface 5b. The external toothed ratchet wheel provides an optimal locking protrusion 5a that allows rotation in the tightening direction and prevents rotation in the loosening direction. The locking portion 11 of the locking nut 10 that fits into the outer meshing surface 5b will be described later.

At the tip of the first engagement portion 5, a second engagement portion 6 is provided having a tool engagement protrusion 6a that engages with the tip of the inner member 25 of the fastening tool 20 described below. The second engagement portion 6 is, for example, a regular hexagonal prism whose corners form the tool engagement protrusions 6a. However, it may also be a triangular prism, a square prism, or the like, as long as the tool can be engaged. If the second engagement portion 6 has a polygonal cross section, it can be easily tightened with a tool such as a wrench or pliers.

As shown in FIG. 3(c), the circumferential pitch P1 of the anti-loosening protrusions 5a is smaller than the circumferential pitch P2 of the tool engagement protrusions 6a of the second engagement portion 6 (i.e., the distance between the vertices of the hexagonal prism) (P1<P2). In this way, by reducing the circumferential pitch P1 of the anti-loosening portion 11, the anti-loosening effect is improved, and by increasing the circumferential pitch P2 of the tool engagement protrusions 6a, the torque of the tool can be easily transmitted.

As shown in an enlarged view in FIG. 3(b), the maximum outer diameter D1 of the first engagement portion 5 is larger than the maximum outer diameter D2 of the second engagement portion 6 (D1>D2). A step portion 7 is provided between the first engagement portion 5 and the second engagement portion 6. In this way, by providing the step portion 7 between the two engagement portions 5, 6, it is possible to prevent the first engagement portion 5 from being scratched by a tool engaged with the second engagement portion 6. The size of the step portion 7 is not particularly limited, but if it is too small, the effect is reduced. Also, as shown in the figure, the maximum diameter D1 of the first engagement portion is smaller than the maximum diameter D3 of the male thread portion and larger than the maximum diameter D2 of the second engagement portion (D2<D1<D3).

- Configuration of fastening tool for bolt with engaging part -
As shown in Fig. 1 and Fig. 2, in this embodiment, a dedicated fastening tool 20 is used to fasten the above-mentioned engaging bolt 1. The fastening tool 20 of the present invention includes a cylindrical outer member 24 whose base end is fixed to the electric tool 21, which is arranged at a distance from the rotating shaft 21a of the electric tool 21 in the radial direction, and which prevents the locking nut 10, which is temporarily fixed to the engaging bolt 1 at its tip end, from rotating. Specifically, the outer member 24 includes, for example, four legs 22 whose base end is fixed to the main body of the electric tool 21 and whose tip end is fixed to the leg mounting hole 23c of the disk-shaped flange portion 23. The legs 22 are arranged at 90° intervals in the circumferential direction, and each of them is sufficiently spaced from the rotating shaft 21a of the electric tool 21 in the radial direction. By using the legs 22 to attach the tool to the electric tool 21, it is possible to relatively easily and reliably attach the tool even if the shape of the electric tool 21 is different.

As shown in a partially enlarged view in FIG. 2, the outer member 24 has a cylindrical shape with a regular hexagonal cross section, and its base end is inserted into the through hole 23a of the flange portion 23, and its chamfered portion 24c abuts against the flat surface 23b formed in the through hole 23a, and is fixed to the flat surface 23b with a fastening member (not shown).

A nut through hole 24b with a regular hexagonal cross section is provided at the tip side of the outer member 24, and the anti-loosening nut 10 described below can be fitted into this nut through hole 24b.

As shown in FIG. 7, an opening 24a is provided on, for example, the upper surface side of the outer member 24, which exposes the anti-loosening nut 10 and the tip side of the engagement bolt 1 that are prevented from rotating by the outer member 24. Note that such an opening may also be provided on the underside. Providing an opening on the underside also improves workability.

Inside the outer member 24, inner members 25 are arranged with radial spacing. As shown in a partially enlarged view in FIG. 2, the inner member 25 is, for example, cylindrical with a regular hexagonal cross section, with a hexagonal engaged hole 25a formed therethrough. The base end of the engaged hole 25a is fixed to the rotating shaft 21a so as to rotate together with the rotating shaft, and the tip end is adapted to engage with the second engaging portion 6 at the tip of the engaging portion-equipped bolt 1.

The outer member 24 and the inner member 25 may be painted, plated, etc., to prevent corrosion.

As shown in FIG. 6, the locking nut 10 has a female threaded portion 12 on the inner peripheral surface at the base end that screws into the male threaded portion 4 of the engaging bolt 1, and a split portion 13 having a locking portion 11 that engages with the locking protrusion 5a of the first engaging portion 5 of the engaging bolt 1 is integrally molded at the tip end. In this embodiment, the locking portion 11 is an inner ratchet wheel that fits into the locking protrusion 5a (outer ratchet wheel) of the first engaging portion 5. The locking nut 10 is, for example, the same one-piece molded product made of reinforced fiber resin as the engaging bolt 1.

As shown in an enlarged view in FIG. 6(c), the locking portion 11 has an inner meshing surface 11a that is included in the same imaginary plane as the axis of the locking nut 10, and an inner tapered surface 11b that is inclined from the tip of the inner meshing surface 11a toward the tightening direction of the female thread portion 12 relative to the inner meshing surface 11a.

A smooth buffer section 14 is provided between the anti-loosening section 11 and the female thread section 12, and the dividing section 13 has multiple, for example, four, notches 15 spaced apart in the circumferential direction.

The inner member 25 has an engaged hole 25a that supports the second engaging portion 6 of the engaging bolt 1 so that it can advance and retreat in the axial direction. In this embodiment, the engaged hole 25a is configured as a regular hexagonal through hole that matches the regular hexagonal column shape of the second engaging portion 6. As a result, when the engaging bolt 1 is screwed in by the power tool 21, the second engaging portion 6 advances through the engaged hole 25a while the locking nut 10 is fixed by the outer member 24, so that the engaging bolt 1 is not hindered from screwing in.

-Method of fastening bolt with engaging part-
First, in a preparation step, the above-mentioned fastening tool 20 is prepared and fixed to the power tool 21. A necessary number of the above-mentioned engaging bolts 1 and locking nuts 10 are prepared. Although not shown in particular, washers made of, for example, fiber-reinforced resin may also be prepared if necessary.

Next, in the temporary fastening process, the engaging bolt 1 is inserted through the through holes of the first fixed member 31 and the second fixed member 32 from the first fixed member 31 side, and the locking nut 10 is temporarily fastened to the tip of the engaging bolt 1 from the second fixed member 32 side, as shown in FIG. 5. The temporary fastening can be performed within a range that allows easy rotation by hand, but it is desirable that the male threaded portion 4 of the engaging bolt 1 and the female threaded portion 12 of the locking nut 10 engage with each other.

Next, in the bolt engagement process, the tip of the outer member 24 is inserted from the locking nut 10 side, and the engaged hole 25a at the tip of the inner member 25 is engaged with the second engaging portion 6 of the engaging bolt 1.

Next, in the fastening process, the rotating shaft 21a of the power tool 21 is rotated to screw in the engaging bolt 1, and as shown in FIG. 4, the first fixed member 31 and the second fixed member 32 are fastened, and the first engaging portion 5 of the engaging bolt 1 is engaged with the anti-loosening portion 11 of the nut 10 to prevent loosening. At this time, as shown in FIG. 7, the anti-loosening nut 10 and the tip of the engaging bolt 1 are exposed from the opening 24a of the outer member 24, so the tightening work can be performed reliably while viewing them.

In this fastening process, as shown by the arrow in Figure 5, while the engaging bolt 1 is being screwed into the locking nut 10, the second engaging portion 6 of the engaging bolt 1 is inserted into the engaged hole 25a of the inner member 25. In this way, when the engaging bolt 1 is screwed in by the power tool 21, the engaging portion advances in the engaged hole 25a while the nut 10 is fixed by the outer member 24, so the engaging bolt 1 is not hindered from screwing in.

In this embodiment, the first engagement portion 5 is fastened to the locking portion 11 of the locking nut 10 to provide an anti-loosening effect. In addition, the male thread portion 4 can be screwed in and fastened by engaging and rotating the fastening tool 20 using the tool engagement protrusion 6a from the tip side.

In this embodiment, the engaging bolt 1 and the locking nut 10 are temporarily fixed at the tip of the outer member 24 and the inner member 25, respectively, and the rotating shaft 21a of the power tool 21 is rotated, so that the male threaded portion 4 of the engaging bolt 1 screws into the female threaded portion of the locking nut 10, reliably locking the first fixed member 31 and the second fixed member 32 together, and providing an anti-loosening effect between the first engaging portion 5 and the locking portion 11.

As explained above, according to the present invention, the second engagement portion 6 for tool engagement is provided beyond the first engagement portion 5 for preventing loosening, so that the bolt 1 with engagement portion can be prevented from loosening and can be fastened only from one side of the fastened member.

In addition, with the bolt 1 with engagement part according to this embodiment, the second engagement part 6 for tool engagement is provided beyond the first engagement part 5 for preventing loosening, so the fastening bolt can be prevented from loosening and can be fastened only from one side of the fastened member.

Note that the above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

1 Volt
1. Bolt with engagement part
2 Bolt head
3 Bolt body
4 Male thread
5 First engagement portion
5a Anti-loosening protrusion
5b Outer meshing surface
5c Outer tapered surface
6 Second engagement portion
6a Tool engagement protrusion
7. Step
10 Anti-loosening nut
11 Anti-loosening part
11a Inner meshing surface
11b Inner tapered surface
12 Female thread portion
14 Buffer section
15 Notch
20 Fastening tools
21 Power tools
21a Rotation shaft
22 Legs
23 Flange portion
23a through hole
23b Flat surface
23c Leg mounting hole
24 Outer member
24a Opening
24b Nut through hole
24c Chamfered part
25 Inner member
25a Engaged hole
31 First fixed member
32 Second fixed member

Claims (7)

A bolt head that can be gripped and tightened with a tool;
a rod-shaped bolt body continuous with the bolt head;
A male thread portion at the tip side of the bolt body;
a first engagement portion having anti-loosening protrusions provided at intervals in a circumferential direction at a tip of the male thread portion;
A bolt with engaging portion, further comprising a second engaging portion provided at a tip end of the first engaging portion and having a protrusion for tool engagement. 2. The bolt with engaging portion according to claim 1, wherein a circumferential pitch of said anti-loosening projections is smaller than a circumferential pitch of said tool engaging projections of said second engaging portion. The maximum outer diameter of the first engagement portion is larger than the maximum outer diameter of the second engagement portion,
3. The bolt with engaging portion according to claim 1, wherein a step is provided between the first engaging portion and the second engaging portion. 4. The bolt with engaging portion according to claim 1, which is an integrally molded product made of a fiber-reinforced resin. 5. The bolt with engaging portions according to claim 1, wherein a maximum diameter of the first engaging portion is smaller than a maximum diameter of the male thread portion and is larger than a maximum diameter of the second engaging portion. The anti-loosening protrusions of the first engagement portion extend in the longitudinal direction of the bolt body and form ridges arranged at equal intervals in the circumferential direction,
6. The bolt with engaging portion according to claim 1, wherein the second engaging portion has a polygonal cross section. 7. The bolt with engaging portion according to claim 6, wherein the anti-loosening projection of the first engaging portion is an externally toothed ratchet wheel.