JP4029368B2 - Bolt fastening device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fastening device for a large bolt such as a foundation bolt for fixing a leg of a steel tower of a high-voltage power transmission line.
[0002]
[Prior art]
The legs of the high-voltage power transmission tower are fixed to the foundation concrete via large foundation bolts (anchor bolts). That is, the bolt hole of the leg portion is inserted into the foundation bolt protruding from the foundation concrete, and fastened with a nut from above.
However, since such a nut can be loosened and removed with a widely used spanner or the like, there is an accident that the steel tower collapses by loosening the nut.
In order to solve such a problem, a special nut that is difficult to remove with an ordinary spanner or the like has been proposed (Japanese Patent Laid-Open No. 7-219780). The nut has a substantially trapezoidal outer periphery in the axial section, and a nut body whose outer periphery is formed as a trapezoidal rotating curved surface, and the outer periphery of the nut body is 180 degrees different in the circumferential direction and different in height by H It is provided with a pair of slits formed at positions.
[0003]
[Problems to be solved by the invention]
However, when attaching a tool to the above special nut and fastening a bolt, the shape and size of the part where the tool is attached to the nut is limited, so there is a limit to the rotational force to fasten or remove the nut, and the bolt is large There was a problem that the fastening and demounting operations became more difficult as the time became.
Therefore, the present invention aims to provide a bolt fastening device that solves such problems, and takes the following configuration in order to achieve the object.
[0004]
[Means for Solving the Problems]
The bolt fastening device of the present invention includes a nut 1 provided with a tool mounting portion 3 having a relatively weak outer peripheral surface, the peripheral surface of the radial direction being a tapered taper or a tapered curved surface, the peripheral surface being formed as a rotating curved surface,
An axial force application device 12 screwed to the bolt 15 together with the nut 1;
The nut 1 is fastened by the tool 8 mounted on the tool mounting portion 3 only when the axial force is applied in a direction in which the axial force applying device 12 is screwed onto the bolt 15 and is tightened. 1 can be loosened, and the tool fitting portion 3 is weak enough to break when the tool is fitted there and the nut is loosened without using the axial force applying device 12. It is characterized by being formed.
[0005]
In a preferred embodiment of the fastening device, the tool mounting portion 3 is a protrusion 5 provided at an end 4 in the axial direction of the nut 1 or a hole 7 provided in an outer peripheral portion 6 of the nut 1. .
In another preferred embodiment of the fastening device, the axial force applying device 12 includes a cylindrical main body 13 screwed to the bolt 15 and a hydraulic device 14 that presses it in the axial direction.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an example of a nut constituting the bolt fastening device of the present invention and a tool suitable for rotating the nut. The nut 1 has a trapezoidal outer periphery in the axial section, and the outer periphery is formed as a trapezoidal rotating curved surface. A relatively fragile tool mounting having an inner screw 2 at the center and a plurality of cylindrical protrusions 5 at equal intervals (in this example, four at 90 ° intervals) on the end 4 on the small radius side. Part 3 is provided. A hooking portion 10 of a tool 8 described later is detachably locked to the tool mounting portion 3, but when a nut is fastened to a bolt without using an axial force applying device described later, or When it is loosened, it is weak enough to break. Instead of providing the protrusion 5 at the end 4, the tool mounting portion 3 can also be configured by providing a plurality of circular holes 7 having a circular cross section such as dotted lines on the outer peripheral portion 6. Further, the projection 5 can have a prismatic shape such as a square or hexagon in cross section, and the hole 7 can also have a square hole shape such as a square or hexagon in cross section.
[0007]
The nut 1 may be formed such that the trapezoidal slope is not linear, but is a curved surface slightly convex outward or a curved surface slightly concave inward. Furthermore, a trapezoidal slope may be formed by a plurality of broken lines. In the present invention, these curved shapes and the straight shapes as shown in FIG. 1 are included.
The tool 8 has an elongated flat plate-shaped handle portion 9 and a flat plate-like engaging portion 10 that is divided into two and then extends. An arcuate recess 11 having an inner diameter that can be engaged with the protrusion 5 is formed on the inner side of each end of the engagement portion 10.
In addition, when the some hole part 7 shown with a dotted line in FIG. 1 is provided as the tool mounting part 3, the tool which has a column-shaped front-end | tip part which has an outer diameter which can be inserted in the internal diameter of the hole part 7 as an engaging part. Can be used.
[0008]
FIG. 2 is a partially broken perspective view showing a state in which the axial force application device constituting the bolt fastening device of the present invention and the nut 1 are combined to fasten or detach a tower leg from a foundation bolt (hereinafter simply referred to as a bolt). FIG.
The axial force application device 12 includes a cylindrical main body 13 that is screwed onto a bolt 15 and a hydraulic device 14 that presses the main body 13 in the axial direction (upward in FIG. 2). The radius of the main body 13 is changed in a stepped shape, and an inner screw 16 that is screwed to the bolt 15 is formed at the center thereof. The outer periphery of the upper part having a large radius is knurled to prevent slipping, and a plurality of rotation holes 17 are formed at equal intervals so that the outer periphery of the lower part having a small radius can be slid in the hydraulic device 14 in the axial direction. And it is mounted coaxially.
[0009]
The hydraulic device 14 includes an annular cylinder 18 disposed so as to surround a lower outer periphery of the main body 13, and an annular piston 19 that is mounted in the cylinder 18 and moves up and down. The cylinder 18 is provided with a pipe connecting portion 20 for connecting a hydraulic pipe.
A cylindrical support 21 is connected to the lower portion of the cylinder 18. A part of the support 21 is cut out so as to form an opening 22, and a nut 1 can be rotated by inserting a tool from the opening 22 as will be described later.
[0010]
Next, the operation of the bolt fastening device of the present invention will be described with reference to FIG. 2. The bolt 15 embedded in the foundation concrete 23 is inserted into the bolt hole of the installation base 24 in the leg portion of the steel tower. Then, a hydraulic pipe from the hydraulic control device is connected to the pipe connection portion 20 of the hydraulic device 14. In order to fasten the bolt in this state, first, the nut 1 is temporarily screwed onto the bolt 15 while rotating by hand. Next, the main body 13 of the axial force application device 12 is manually rotated so as to cover the nut 1 and screwed to the bolt 15, and stopped at a position where the bottom of the support 21 contacts the upper surface of the installation base 24. Then, if necessary, a rod-shaped tool is inserted into the hole 17 and the main body 1 is rotated so that the bottom of the support 21 is strongly pressed against the upper surface of the installation base 24.
[0011]
Next, when hydraulic pressure is supplied from a hydraulic control device (not shown) and a rising force is applied to the piston 19 of the hydraulic device 14, the main body 13 tensions the bolt 15 (that is, pulls the bolt 15 in the axial direction). Then, since the bolt 15 is stretched and a gap is formed between the nut 1 and the installation base 24, the tool 8 is inserted from the opening 22 of the support 21, and the engaging portion 10 is engaged with the tool mounting portion 3 of the nut 1. Install. Then, by rotating the tool 8 in the direction in which the nut 1 is tightened, the nut 1 is fastened to the bolt 15 with a predetermined axial force. When one nut 1 is fastened, the axial force applying device 12 is removed from the bolt 15 and the next bolt fastening operation is started. Alternatively, by using a plurality of the axial force application devices 12, nuts can be fastened to a plurality of bolts in parallel and with an equal fastening force.
[0012]
Next, in order to remove the nut 1 fastened as described above from the bolt 15, the main body 13 of the axial force application device 12 is first rotated by hand so as to cover the nut 1, as in the fastening operation. It is screwed to the bolt 15 and stops at a position where the bottom of the support 21 contacts the upper surface of the installation base 24. Next, when the hydraulic pressure is supplied from the hydraulic control device to apply a lifting force to the piston 19 of the hydraulic device 14 to tension the bolt 15, the bolt 15 is stretched and a gap is formed between the nut 1 and the installation base 24. And the tool 8 is inserted from the opening part 22 of the support body 21, the engaging part 10 is engaged and attached to the tool attaching part 3 of the nut 1, the tool 8 is rotated, and the nut 1 is loosened. Next, the axial force applying device 12 is removed from the nut 1, and the nut 1 is loosened and detached by hand.
In addition, the tool fitting part 3 of the nut 1 is formed to be weak enough to be damaged when an appropriate tool is fitted therein and the nut is loosened without using the axial force applying device 12. ing.
[0013]
【The invention's effect】
The bolt fastening device of the present invention cannot be gripped by a normal tool because the outer peripheral surface of the nut is formed as a tapered or tapered curved surface and a rotating curved surface. In addition, nuts cannot be fastened or removed without using an axial force application device together with a specific tool, so it is possible to effectively prevent loosening and removal of nuts at the base of high-voltage power transmission towers. Can do. Further, even a large nut can be easily fastened or detached. Further, the bolt can be fastened with a predetermined axial force by the axial force applying device.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a nut constituting a bolt fastening device of the present invention and a tool attached to the nut.
2 is a partially broken perspective view showing a state where a bolt is fastened or detached using the nut and the axial force application device of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Nut 2 Inner screw 3 Tool mounting part 4 End part 5 Protrusion part 6 Peripheral part 7 Hole part 8 Tool 9 Handle part 10 Engagement part 11 Recess part 12 Axial force application apparatus 13 Main body 14 Hydraulic apparatus 15 Bolt 16 Inner thread 17 Hole part 18 Cylinder 19 Piston 20 Piping connection 21 Support 22 Opening 23 Foundation concrete 24 Installation base

Claims (3)

A nut 1 having a radially circumferential surface tapered or tapered, and a circumferential surface formed as a rotating curved surface, and a relatively weak tool mounting portion 3 provided on the outer periphery;
An axial force application device 12 screwed onto the bolt 15 together with the nut 1;
The nut 1 is fastened by the tool 8 mounted on the tool mounting portion 3 only when the axial force is applied in a direction in which the axial force applying device 12 is screwed onto the bolt 15 and is tightened. 1 can be loosened, and the tool fitting portion 3 is weak enough to be damaged when a tool is fitted therein and the nut is loosened without using the axial force applying device 12. A bolt fastening device which is formed. The bolt fastening device according to claim 1, wherein the tool mounting portion 3 is a protrusion 5 provided at an end 4 in the axial direction of the nut 1 or a hole 7 provided in an outer peripheral portion 6 of the nut 1. The bolt fastening device according to claim 1 or 2, wherein the axial force applying device 12 includes a cylindrical main body 13 screwed to the bolt 15 and a hydraulic device 14 that presses the main body 13 in the axial direction. .

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