JP2001235379A - Socket for measuring axial force incorporated with ultrasonic probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make highly reliably measurable axial force while fastening a screw in a method for measuring the axial force of a bolt using ultrasonic. SOLUTION: A retainer plate 7 with an ultrasonic probe 8 fixed is assembled in a socket 1 for fastening screw, and energized in the direction toward the tip of the socket 1 by a compression spring 6 between the retainer plate 7 and a sliding body 6. The sliding body 6 abuts to a stepped flange 16 eccentrically provided at a center part of an eccentric shaft 13, and energizing action is switched by swing of eccentric shaft 13. When the energizing action is switched to act, the ultrasonic probe 8 comes into contact with a head part 3 of the belt 2, and the axial force can be measured simultaneously with fastening work using a handle engaged to a drive 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a socket for measuring an axial force in which an ultrasonic probe is incorporated, and is suitable for measuring an axial force when tightening a bolt.

[0002]

2. Description of the Related Art As a method for measuring the axial force of a bolt, a method using an ultrasonic wave is known to be capable of relatively high precision measurement. This method utilizes the property that the speed of sound changes according to the elongation generated by the elastic deformation of the bolt due to tightening, and obtains the axial force by converting the measured value. Specifically, as shown in FIG. 6, an axial force measuring device is constituted by an ultrasonic probe 8 as a sensor and an axial force meter 20 having an analysis / calculation function. The ultrasonic probe 8 transmits an ultrasonic pulse 21 toward the tip of the bolt 2 and receives the echo, and the axial force meter 20 determines the axial force based on the measured propagation time of the ultrasonic wave. Is calculated.

[0003] The ultrasonic probe 8 is placed in contact with the head of the bolt 2 in a tightened state. At this time, conventionally, a method of keeping the ultrasonic probe 8 on the head of the bolt 2 or fixing it with an adhesive or the like has been adopted.

[0004]

If the ultrasonic probe is left on the bolt during measurement, the workability is poor due to unstable fixing, and the ultrasonic probe is susceptible to external vibrations. The characteristics of ultrasonic measurement, such as high accuracy and high reliability, cannot be utilized. The fixing method using an adhesive or the like still has problems in workability such as application and removal thereof and attachment and detachment of the ultrasonic probe. What matters most is that the screw tightening operation can only be performed by inserting a wrench from the side of the head of the bolt, so that simultaneous measurement while actually tightening is difficult.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an ultrasonic probe in contact with a bolt from an axial direction thereof, and an echo of an ultrasonic pulse transmitted from the ultrasonic probe. In the axial force measuring device which calculates the axial force of the bolt from the above, the ultrasonic probe is incorporated in a socket for screw tightening, and the socket has a function of pushing out the ultrasonic probe to make contact with the bolt. It is characterized in that it has a biasing means and a switching means for restraining the biasing action to make it non-contact.

Further, the urging means may be formed by a compression spring, or an ultrasonic probe may be formed integrally with the magnet, and a repulsive force may be generated between the magnet and another magnet incorporated in the socket. Characterized by being formed by: Further, the switching means is formed by turning an eccentric shaft, and a recess is provided in the eccentric shaft, and the tip of the plunger is engaged with the recess to determine the position of the turning position of the eccentric shaft. It is characterized by being performed.

The socket can be inserted from above the head of the bolt. Then, if the switching means incorporated in the socket is operated to switch the urging means so that the urging action of the urging means works, the ultrasonic probe is urged toward the distal end, so that the ultrasonic probe surely comes into contact with the bolt. An eccentric shaft is employed as a simple switching means. Since the eccentric shaft is provided with a positioning device, it is temporarily locked at the set turning position. A compression spring is used as the urging means, and a means utilizing the repulsive force of the magnet is selected for higher accuracy. This is because the compression spring method may be affected by external vibration along the spring, but the magnet method excludes this. In either case, the socket of the present invention enables axial force measurement while performing bolt tightening work.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 are sectional views of a socket according to the present invention.
A socket portion 4 that engages with the head 3 of the bolt 2
Are drilled. On the other hand, a drive 5 that engages with the convex drive of the handle is recessed at the upper end. Then, various components related to the present invention are stored inside the socket, but cannot be assembled with the configuration shown in these figures. Actually, the socket body and components are assembled in an appropriate divided structure, but are omitted in the figure to avoid complication.

A cylindrical sliding body 6 is slidably inserted into the socket 1. At the tip of the sliding body 6, an inverted conical hole with a small opening is formed, and a through hole is formed at the center axis. In the inverted conical hole,
A holding plate 7 having an outer peripheral shape to be engaged with the holding plate 7 is incorporated so as to be vertically movable. A hole also penetrates through the center of the holding plate 7.

An ultrasonic probe 8 is fixed to the lower surface of the holding plate 7. The ultrasonic probe 8 is formed by a thin plate-shaped sensor portion and another main body portion. A lead wire 9 is drawn out from the upper end, passes through the center hole of the holding plate 7 and the sliding body 6, and passes through a socket. Exiting from a suitable location and extending to a dynamometer. A plurality of compression springs 10 are equally arranged in the circumferential direction and held between the holding plate 7 and the sliding body 6, and always act to push the holding plate 7, and consequently, the ultrasonic probe 8 in the distal direction. It is a force.

A plurality of plungers 11 parallel to the axis are equally arranged in the circumferential direction near the outer periphery of the cylindrical sliding body 6. The tip is in contact with the surface of a disc-shaped lid 12 with a hole pressed into the socket 1. The total spring force of the plunger 11 is set to be larger than the total spring force of the compression spring 10. When the sliding member 6 is not restrained, the sliding member 6 and, thus, the ultrasonic probe 8 are lifted upward. It acts to push up.

An eccentric shaft 13, which is an embodiment of the switching means of the present invention, is diametrically installed at a substantially central portion of the socket 1. One end of the eccentric shaft 13 protruding outside is a knob 14 for turning operation. An E-shaped retaining ring 15 is fitted into the other end to prevent the retaining ring from coming off. In addition, the center of the eccentric shaft 13 has an axis P at a position eccentric from the axis O.
A stepped flange 16 having a large diameter and a small diameter is provided around the center. And the stepped flange 16
The large-diameter portion is configured to have a positional relationship in contact with the bottom surface of the groove provided on the upper end surface of the sliding body 6.

The socket 1 is incorporated so that the tip of the plunger 17 contacts the outer periphery of the small diameter portion of the stepped flange 16. For example, a conical recess 18 is provided on the outer periphery of the small-diameter portion so that when the tip of the plunger 17 engages with the recess 18, it can be temporarily locked at that position. The turning position of the eccentric shaft 13 can be determined by appropriately determining the arrangement position of the recess 18.

In the socket 1 configured as described above, FIG. 1 shows a state in which the urging means is restrained and the ultrasonic probe 8 is not in contact with the head 3 of the bolt 2. . That is, since the axis P of the stepped flange 16 is eccentric just above the axis O of the eccentric shaft 13,
The sliding body 6 is in a state of being lifted to the uppermost position by the plunger 11. As a result, the ultrasonic probe 8 is also lifted up. At this time, the tip of the plunger 17 engages with one of the recesses 18 and the eccentric shaft 13
Is positioned in the turning direction.

The knob 14 of the eccentric shaft 13 is connected to the plunger 11
Is rotated 180 ° against the spring force of the above, the axis P comes directly below the axis O, and the stepped flange 16 is at the lowest position. Since the sliding body 6 is pushed down in conjunction with this,
The ultrasonic probe 8 urged by the compression spring 10 comes into contact with the head 3 of the bolt 2. Therefore, the amount of movement of the sliding body 6 by the eccentric shaft 13 needs to be set to be greater than the distance between the head 3 of the bolt 2 and the ultrasonic probe 8. Then, the tip of the plunger 17 is engaged with the recess 18 arranged symmetrically with the recess 18, and the eccentric shaft 1
3 are determined.

If the convex drive at the end of the handle is inserted into the drive 5 and rotated, the axial force can be measured every moment while the bolt 2 is being tightened. Then, when the fastening operation is stopped when the set axial force is reached, the fastening with an accurate axial force can be obtained. If the knob 14 is further rotated by 180 ° for switching, it is possible to return to the state where the socket 1 shown in FIG. 1 can be removed.

FIG. 5 shows another embodiment of the present invention, and the same parts as those described above are denoted by the same reference numerals. This figure is
As in FIG. 1, this shows a state in which the ultrasonic probe 8 is out of contact. The outer peripheral portion of the ultrasonic probe 8 is formed of a cylindrical magnet, the inside of which is filled with resin or the like, and a thin plate-shaped sensor portion is fixed to the inner end. On the other hand, the magnet 19 is also incorporated inside the sliding body 6,
Further, it is arranged with a polarity that repels the ultrasonic probe 8. The repulsive force acting between the magnets is used as the urging means. At the time of measurement, the ultrasonic probe 8 and the sliding body 6 are used.
As a result, the influence of external vibration is eliminated, and the axial force can be measured more reliably than in the case where the compression spring is used.

[0018]

By incorporating an ultrasonic probe into a socket for axial force measurement, it is possible to perform bolt tightening work using an ordinary socket wrench and measure axial force at the same time. Become. The socket is constituted by an urging means and a switching means, and this is realized by using a repulsive force of a compression spring or a magnet as the urging means and using an eccentric shaft as the switching means. The measurement operation is simple and reliable compared to a conventional method in which an ultrasonic probe is mounted or adhered, and the characteristics of highly accurate measurement using ultrasonic waves are utilized. The urging means using a magnet is more suitable for a work environment with a lot of vibration since vibration from the outside is hardly transmitted. Furthermore, the socket according to the present invention can be adapted to full automation by operating the drive portion and the knob portion with a nut runner.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the socket of the present invention.

FIG. 2 is a bottom view of FIG.

FIG. 3 is a plan view of FIG. 1;

FIG. 4 is a side view of FIG. 1;

FIG. 5 is a front view showing another embodiment of the socket of the present invention.

FIG. 6 is a configuration diagram of an axial force measuring device.

[Description of Signs] 1 Socket 2 Bolt 4 Socket 5 Drive 6 Slider 8 Ultrasonic Probe 10 Compression Spring 11 Plunger 13 Eccentric Shaft 16 Stepped Flange 19 Magnet O (Eccentric Shaft) Axis P (Stepped Flange) Axis

Continued on the front page F term (reference) 2F051 AB04 BA00 3C038 AA01 AA03 BB08 BC02 CA01 CA05 DA01 EA02 EA06

Claims (5)

[Claims] 1. An axial force measuring device, wherein an ultrasonic probe is brought into contact with a bolt from an axial direction thereof, and an axial force of the bolt is calculated from an echo of an ultrasonic pulse transmitted from the ultrasonic probe. The ultrasonic probe is incorporated in a socket for screw tightening, and the socket has biasing means for pushing out the ultrasonic probe to make contact with the bolt, and switching means for restraining the biasing action so as to make it non-contact. A socket for measuring axial force in which an ultrasonic probe is incorporated. 2. The socket for axial force measurement according to claim 1, wherein said urging means is formed by a compression spring. 3. The ultrasonic probe according to claim 2, wherein the ultrasonic probe is formed integrally with a magnet, and the urging means is formed by a repulsive force between the ultrasonic probe and another magnet incorporated in the socket. A socket for measuring an axial force in which the ultrasonic probe according to 1 is incorporated. 4. The axial force measuring device according to claim 1, wherein said switching means is formed by turning an eccentric shaft. socket. 5. The eccentric shaft is provided with a recess, and the tip of the plunger is engaged with the recess to determine the turning position of the eccentric shaft. A socket for measuring an axial force in which the described ultrasonic probe is incorporated.