JPH0650748Y2 - Bolt looseness detector - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a looseness detecting device for a bolt fastening a steel structure such as a bridge, and in particular, an impact force of a hammer is generated by an elastic body. A bolt looseness detection device is provided.

[Conventional technology]

For example, steel structures such as bridges are fastened and assembled using a large number of bolts. At the time of assembling or completing this steel structure, or when a certain period of time has passed, it is necessary to inspect the looseness of bolts to confirm the safety of the structure. In general, as a bolt looseness inspection method, a method of hitting the head or nut of the bolt with a hammer for hitting inspection and making a judgment by a person by the hitting at that time is used. However, this method often relies on "intuition" with people, and as a result, there are large individual differences, and it is not possible for an expert to make an accurate judgment. There was a problem that even a skilled person would make a different judgment.

Therefore, as a result of diligent study on bolt loosening detection, the present inventor hits the hexagonal planes of bolts and nuts in the shearing direction, detects the force and / or acceleration due to this hit, and detects this detection signal. Have proposed a method for detecting looseness of bolts and a device for detecting looseness of bolts (see, for example, Japanese Patent Application Nos. 62-252551 and 1-24040).

[Problems to be solved by the device]

By the way, the previously proposed bolt loosening detection device directly drives a hammer provided at the tip of the main body by a solenoid coil, but such a solenoid coil drive detection device has a relatively large bolt diameter. Moreover, it becomes a problem when the bolt intervals are small.

That is, for example, a striking force of about 1 ton is required to determine the looseness of the bolt of the steel structure in which the M22 bolt is arranged at 75 mm. Because of the size of the detector, the stroke of the hammer is about this.)
It is necessary to supply 200V, 10A high voltage, large current power to the solenoid coil.

Therefore, not only the work is dangerous because high voltage and large current are handled, but also the coil for obtaining a large magnetic force becomes large, and as a result, the weight of the device becomes large. This increases worker fatigue. In addition, there is a problem that a device for storing special electricity is required to obtain high voltage and large current.

[Means for Solving the Problems]

The bolt looseness detection device according to the present invention is made to solve the above-mentioned problems, and includes a main body having a fixing portion at a tip end portion that engages with a head portion of a nut or a bolt, and One end is pivotally supported at the rear end of the main body, and the other end has an arm having a hammer for striking the hexagonal plane of the head of the nut or bolt fitted to the fixing part, and the central part of the main body. A cam member that is provided and that is rotated by a driving device to operate so as to separate the arm from the main body; and an elastic force that is stretched between the arm and the main body and that pulls the arm toward the main body. It is composed of an elastic body that gives

[Action]

In the bolt looseness detecting device having the above-mentioned structure, the arm having the hammer fixed to the tip is always drawn toward the main body by the elastic body (spring), and the arm is moved to the base part by rotating the cam member. Is gradually opened against the tension of the elastic body with the fulcrum as a fulcrum, and the receiving seat constituting the cam member provided on the arm is pulled toward the main body side at the same time as it is disengaged from the cam It is possible to hit the hexagonal plane of the head of the nut or bolt with a hammer.

〔Example〕

An embodiment of a bolt looseness detecting device according to the present invention will be described below with reference to the drawings.

FIGS. 1 to 4 show a first embodiment of a bolt looseness detecting device, FIG. 1 is a side view thereof, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 2 is a view taken along the line III-III in FIG. 2, and FIG. 4 is a sectional view taken along the line IV-IV in FIG.

The bolt looseness detecting device is composed of a main body 1, an arm 2 pivotally supported at one end of the main body 1, and a fixing portion 3 that engages with the hexagonal surface of the head of the bolt / nut 19.

Specifically, a motor 6 with a speed reducer 6a is attached to the main body 1 with a bolt 4 via an attachment member 5, and a cam 7 is rotated by the motor 6 about a shaft 8. The cam 7 can abut against a pressing member (receiving seat) 9 described later, and can depress the arm 2 against the spring force of the spring 10.

A cylindrical body 11 is further attached to the main body 1, and a tension spring 10 is arranged between a lower end of a screw shaft 12 provided at the top of the cylindrical body 11 and a mounting piece 13 provided at a lower portion. . A wing nut 14 is screwed onto the screw shaft 12.
By turning 14, the spring force of spring 10, namely hammer 17
It is configured so that the impact force of can be adjusted.

A long hole 15 is formed at the lower end of the mounting piece 13, and a pin 16 provided on the arm 2 is fitted in the long hole 15. That is,
Immediately before the hammer 17 described later hits the hexagonal plane of the bolt / nut 19, the stopper 18 contacts the lower end of the tubular body 11, and the arm 2 is not directly pulled by the spring 10.
In a free state, the hammer 17 strikes one hexagonal plane of the bolt / nut 19 in the shearing direction of the bolt. This gives a good signal.

As shown in FIG. 2, the fixing portion 3 attached to the tip of the main body 1 is configured to be sandwiched by two V-shaped engaging portions on both sides of the hexagonal plane of the bolt / nut 19. And, the open portions 20, 21 are provided above and below the V-shaped engaging portions.
Is provided.

A second member 23 having an acceleration sensor 22 is arranged in the upper opening 20, and a first member 25 having a striking portion projection 24 as shown in FIGS. 2a and 2b is further provided in the lower opening 21. Are arranged respectively, and further, the first material 25 and the second material 23 are arranged.
Is configured so that a tension spring 27 penetrating a hole formed in the mounting portion 26 of the fixed portion 3 integrally presses the fixed portion 3 with the elastic force. Incidentally, FIGS. 2c and 2d show another embodiment of the material 25 of FIG.

Specifically, the distance between the first contact member 25 and the second contact member 23 is arranged to be slightly smaller than the interval between the parallel portions of the hexagonal portions of the bolt / nut 19 that face each other. A tension spring 27 is provided in a tensioned state between the first abutment member 25 and the second abutment member 23 and presses the bolt / nut 19 so as to hold the two surfaces thereof.

In addition, 28 is a stopper attached to the rear side surface of the fixed portion 3 by a screw 29, and this stopper 28 is the fixed portion 3
When inserted into the hexagonal part of the bolt / nut, it functions to determine the position in the depth direction.

The first pad 25 must be able to withstand the impact of the hammer 17, so a hard material such as spring steel or tool steel is used.

As shown in FIG. 1, a grip portion 31 is attached below the main body 1 so that the fixing portion 3 can be accurately fitted into the bolts and nuts 19. Further, a pressing member (receiving seat) 9 that abuts on the cam 7 with a bolt 32 is attached to the arm 2, and a hammer 17 having a force sensor 33 at the tip is provided.

In the above configuration, when detecting the looseness of the bolt,
The hexagonal portion of the bolt / nut 19 is fitted into the fixing portion 3 having a hexagonal opening. At this time, the first strip 25 and the second strip 23 move slightly outward against the spring force of the tension spring 27, so that the first strip 25 and the second strip 23 are separated from each other. Both abut the flat surface of the hexagonal portion of the bolt / nut 19.

Then, a switch (not shown) is turned on to operate the motor 6 and rotate the cam 7 in the direction of arrow e shown in FIG. When the arm 2 is pushed downward against the spring force, that is, the arm 2 is pushed downward from the position indicated by the solid line, and the position indicated by the chain double-dashed line is reached, the pressing member (reception seat) 9 deviates from the angle of the cam 7 and the spring force of the spring 10 The arm 2 is momentarily pulled up, and the hammer 17 attached to the tip of the arm 2 strikes the protrusion 25 of the first contact member 25.

At this time, the force due to the impact is detected as a pulse signal by the force sensor 33 provided on the hammer 17, and the acceleration is detected as a pulse signal by the acceleration sensor 22 provided on the second contact member 23. It is converted and displayed as a waveform by a recording means such as an XY plotter or a printer.

Then, the change of the pulse waveform, specifically, the ratio of the rising angle (or slope) and the falling angle (or slope) of the pulse waveform is obtained and compared with a predetermined value to detect the looseness of the bolt.

Since the acceleration of the hammer 17 is proportional to the force detected by the force sensor 33, the force can be detected by attaching an acceleration sensor instead of the force sensor 33.

In addition, instead of the change of the pulse waveform, for example, a force sensor
It is also possible to detect the looseness of the bolt by calculating the ratio of the signal F obtained from 33 and the signal A obtained from the acceleration sensor 22.

5 to 17 show a second embodiment of the fixing portion 3 of the bolt / nut looseness detecting device.

This fixed part 3 is a flange attached to the tip of the main body 1.
A base 36 attached to the bolt 34 by a bolt 35, a second pad 37, and the like. More specifically, a flange 34 is attached to the tip of the main body 1 as shown in FIGS. 7 and 8. As shown in FIGS. 9 to 11, the base 36 has a vertical member 41 having a notch 38 in the center and a bolt hole 40, and an upper horizontal member protruding from the upper end of the vertical member 41. It is composed of a material 42, a lower horizontal material 43 protruding in parallel with the upper horizontal material 42, an eye plate 44 attached to the lower horizontal material 43, and a lower positioning seat 45 of the hexagonal portion of the bolt / nut 19. Has been done.

The length l of the upper horizontal member 42 and the lower horizontal member 43 is determined so that the tips of the upper and lower horizontal members 42 come into contact with the side surfaces of the structural member when the heads of the bolts and nuts 19 are fitted.
The lower horizontal seat 43 constitutes an abutting member for contacting the side surface of the structure. First base member 46 (FIGS. 16 and 17) bent downward toward the insertion side of bolts and nuts 19 is attached to the lower portion of base 36 with bolts 47, as shown in FIG. And the recess shown in FIG. 12 and FIG.
An upper positioning seat 49 having a bolt 48 for positioning the hexagonal portion of the bolt / nut 19 is attached by a bolt 50. The upper positioning seat 49 is integrally formed by the connecting member 51.

As shown in FIGS. 14 and 5, the second plate 37 is provided with an eye plate 52 in the lower part and an acceleration sensor 53 is attached to the center part thereof.
A tension spring 54 is arranged between 52 and the eye plate 44 provided on the base 36.

In the bolt / nut detecting device having the fixing portion 3 configured as described above, the fixing portion 3 is moved axially in the hexagonal portion of the head of the bolt / nut 19 and fitted therein, After that, in the same manner as in the first embodiment, the hammer 17 strikes the hexagonal plane of the bolt / nut 19 in the shearing direction of the bolt / nut 19 from above the first contact member 46, and the impact force is applied. The force sensor 33 detects the acceleration as a pulse signal by the acceleration sensor 53, the pulse signal is amplified, further A / D converted, and displayed as a pulse waveform, which is obtained by the change or by the force sensor 33. Signal F
The looseness of the bolt is detected by calculating the ratio between the signal A and the signal A obtained from the acceleration sensor 53.

[Effect of device]

As is apparent from the above description, the bolt looseness detection device according to the present invention is provided so as to be opened and closed along the main body, and the arm having the hammer at its tip gradually moves at a predetermined distance by the rotation of the cam member. Open the hammer away from the hexagonal plane of the nut or bolt head. In the meantime, an elastic body provided between the main body and the arm, that is, a spring is tensioned to store elastic energy.

When the cam member is disengaged from the receiving seat of the arm, the arm is instantly attracted to the main body side by the elastic energy and the hammer provided at the tip of the arm causes the nut or the hexagonal plane of the head of the bolt to move to the bolt surface. Since the ball is hit in the shearing direction at a predetermined speed, the following effects can be obtained.

The drive device (motor) for driving the cam does not need to instantaneously generate a large force unlike the solenoid coil, and the high speed rotation of the motor can be mechanically decelerated so that the cam is driven thereby. It eliminates the need for high voltage and high current as in the case of coils. That is, as described above, in order to obtain a striking force of about 1 ton required for detecting looseness of the M22 bolt, a current of 18 V and 1.2 A can be used.

Therefore, not only the work is safe, but also the elastic force is stored in the spring as the motor rotates, and the elastic force is released instantly. Therefore, the detection device can be downsized. Further, there is an effect that a large striking force can be obtained by increasing the spring constant if necessary.

[Brief description of drawings]

1 to 17 show an embodiment of a bolt loosening detecting method and device according to the present invention, and FIGS. 1 to 4 are explanatory views of a nut loosening detecting device of the first embodiment. so,
1 is a side view, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and 2a.
Figures and 2b show a side and front view of the first piece, Figure 2c and
2d is another embodiment of the first material, a side view and a front view, and a third view.
The figure is a view taken along the line III-III in FIG. 2, and FIG. 4 is the line IV-IV in FIG.
FIG. 5 to 17 are explanatory views of a second embodiment of the looseness detecting device for bolts and nuts, and FIG. 5 is a front view of a fixing portion,
FIG. 6 is a side view thereof, FIG. 7 is a side view of the tip of the main body, and FIG. 8 is a front view of the same. 9 is a front view of the base body, FIG. 10 is a side view of the same, FIG. 11 is a plan view of the same, FIG. 12 is a front view of the upper positioning seat, FIG. 13 is the same perspective view, and FIG. FIG. 15 is a front view of the material of No. 2 and its plan view. FIG. 16 is a front view of the first material, and FIG. 17 is a side view of the same. 1 ... Main body, 2 ... Arm 3 ... Fixing part, 17 ... Hammer 19 ... Bolts / nuts, 20,21 ... Opening part 22 ... Accelerometer, 23 ... Second member 24 ... Protrusion, 25 ... First member 33 ... Force sensor, 36 ... Substrate 37 ... Second material, 38 ... Notch 41 ... Vertical material, 42 ... Upper horizontal material 43 ... Lower horizontal material, 45 ... Lower positioning seat 46 ... First material, 48 ... Recessed portion 49 ... Upper positioning seat, 51 ... Connecting material 53 ... Acceleration sensor, 54 ... Tension spring.

Claims (1)

[Scope of utility model registration request] 1. A main body having a fixed portion at a front end portion which engages with a head portion of a nut or a bolt, and a nut having one end pivotally supported at a rear end portion of the main body and the other end fitted to the fixed portion. Or, an arm having a hammer for hitting the hexagonal plane of the head of the bolt, and a cam member provided in the central portion of the main body and operated by a drive device so as to operate so as to separate the arm from the main body. A looseness detecting device for a bolt, which is stretched between the arm and the main body and is made of an elastic body that applies an elastic force to pull the arm toward the main body.