JPH0197575A - Stud bolt detachable shifter - Google Patents

Abstract

PURPOSE: To reduce the torque required to turn a stud bolt and thereby prevent the thread ridges of the stud bolt and of a bolt mounting part from being damaged by providing a cylinder device for producing pressure to cancel the weight of the stud bolt and of a movable part while the stud bolt is unscrewed. CONSTITUTION: With a stud bolt 3 pulled up, an impact wrench 33 is rotated intermittently to turn the stud bolt 3 by way of a fixed shaft 34a, rotary shaft 34b and wrench 35 and to slide the stud bolt 3 in the unscrewing direction. During this process, an air cylinder 40 continues supplying air of a constant pressure from its supply port 44 to move the stud bolt 3 and a movable part vertically at a time and to cancel the deadweight of the stud bolt 3 continuously. When the stud bolt 3 is unscrewed further and disengaged from the spring part 2b of the flange 2a of a barrel body 2, a frame 32 supports the stud bolt 3 and the movable part via the air cylinder 40 to prevent the weight of the stud bolt 3 from acting on the stud bolt 3 itself and on the spring part 2b of the barrel flange 2a.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to stud bolt attachment/detachment, which is applied to, for example, the attachment/detachment of stud bolts of a reactor pressure vessel of a boiling water reactor, and the transfer to/from a storage location. The present invention relates to a stud bolt attachment/detachment device, and more particularly, to a stud bolt attachment/detachment device that can efficiently remove a stuck stud bolt and transfer it thereafter.

[Conventional technology]

In general, the reactor pressure vessel of a boiling water reactor has an upper mirror 1 and a body 2 connected to their flanges 1a and 2, as shown in FIG.
By connecting with stud bolt 3 at part a,
The entire structure is sealed. The details of the connection state using the stud bolts 3 are shown in FIG. screw hole 2
Corresponding to b, the flange la of the upper mirror 1 is provided with the same number of through holes 1b extending in the vertical direction. Stud bolt 3 is
One end (upper end) thereof is inserted into the through hole 1b in a state of protruding above the flange 1a of the upper mirror 1, and the other end (lower end) of the screw portion 3a is screwed into the screw hole 2b of the flange 2a of the body 2. . A nut 4 is attached to the threaded portion 3b of the upper end of the stud bolt 3 via a washer 5, and the upper mirror 1 and the body 2 are connected by the tightening force of the nut 4. The nut 4 and the washer 5 attached to the stud bolt 3 are arranged along the circumferential direction on the flange la of the upper mirror l so close that they nearly touch each other.

Incidentally, in a nuclear reactor pressure vessel, periodic inspections are performed, for example, once a year for fuel exchange and the like, and at that time, the upper mirror 1 is opened and closed. When the upper mirror 1 is released, all the nuts 4 and washers 5 attached to the stud bolt 3 are once removed, and they are attached to the stud bolt 3 again when re-closing after a fuel change or the like. Further, in conjunction with the above-mentioned removal and attachment of the NAND, the stud bolt 3 is also removed and attached. That is, stud bolt 3
corresponds to the fuel exchange passage, and the non-destructive inspection required by law (in-service inspection: 15
Approximately 1/3 of the total is extracted, including those to confirm its soundness in I).

On the other hand, when replacing fuel during a regular inspection period, the dry well 6, equipment pool 7, and fuel boule 8 are filled with water for the purpose of reducing radiation exposure, as shown in FIG. 11, for example. As a result, the stud bolt 3 becomes submerged in water.

Since the stud bolt 3 and the flange 2a of the body 2 are generally made of ferritic alloy steel, rust occurs when submerged in water during periodic inspections.

In particular, since it is stipulated that all +31s must be installed within 10 years, the stud bolts 3 are submerged in water for a long period of time, and the connection between the flange 2a of the fuselage 2 and the stud bolts 3 is
As shown in part B in Figure 0, a gap is formed in the screw hole 2b, and water tends to accumulate in that area, resulting in significant occurrence of mackerel.

If the threaded hole 2b of the flange 2a of the body 2a and the threaded portion 3a of the stud bolt 3 are rusted as described above, a very large amount of effort is required to remove the stud bolt 3. For this reason, conventionally, as shown in FIG. 12, a bolt wrench 9 is first attached to the top of the stud bolt 3, and the lever 9a of the bolt wrench 9 is hit with a hammer to remove rust. That is, when applying static rotational torque, an extremely large torque is required, so by hitting the stud bolt 3 with a hammer, rotational torque is applied to the stud bolt 3, and vibration is applied to the rusted part to release the mackerel. This attempts to rotate the stud bolt 3 with a relatively small force.

Thereafter, as shown in FIG. 13, the stud handling tool 10 is used to remove the stud bolt 3.

Note that the stud bolt 3 has a diameter of approximately 150 mm.

It is approximately 1,800 mm long and weighs approximately 250 kg. For this reason, the stud handling tool 10 includes a spring 11.
is built-in, and by lifting and operating it with an overhead crane etc., it cancels out the weight of the stud bolt 3, reduces the frictional force of the threaded part 3a, and reduces the force applied to the handle 12 to rotate the stud bolt 3. limited. All of these operations are performed manually by workers. Furthermore, the area near the upper mirror flange 1a is a highly radioactive area, and all workers are required to wear masks and dust-proof clothes to prevent exposure to radiation.

[Problems to be Solved by the Invention] According to the above-mentioned prior art, when the bolt wrench 9 is struck with a hammer during normal work in which the stud bolt 3 is removed with the upper mirror l present, the footing is unstable. There is also the problem that the hitting power cannot be fully demonstrated. In addition, it is necessary to change the tool in two stages to remove the stud bolt, which makes work efficiency poor. Usually, only one overhead crane is used, and when removing the stud bolt using the bolt handling tool lO normally. Since only one stud bolt can be handled at a time, work efficiency is poor.

Furthermore, the area around the upper mirror 1 is a highly radioactive contaminated area, and workers must wear masks and dust-proof clothing to prevent exposure to radiation, which further worsens work efficiency. be.

In order to solve the above-mentioned problem, a stud bolt attachment/detachment device has already been proposed for the work of removing or attaching the stud bolt 3 (e.g. Utility Model Publication No. 58-1).
7737, etc.), and a bolt attachment/detachment/transfer device that can transport several stud bolts 3 at the same time in addition to extraction or installation has also been proposed (for example,
9-49148 and Utility Model Publication No. 59-49148, etc.)
.

The former stud bolt attachment/detachment device, like the bolt handling tool shown in Figure 12, has a built-in spring that cancels out the stud bolt's own weight and rotates the stud bolt by applying intermittent impact force. . However, like bolt handling equipment, it is necessary to constantly lift it using an overhead crane or the like. Furthermore, it is necessary to move the device up and down in accordance with the axial movement caused by the rotation of the stud bolt. In addition, workers need constant support, and
Since there is no drive source on the axis of the stud bolt to generate the intermittent impact force to rotate the stud bolt, all the reaction force to rotate the stud bolt is applied to the worker supporting the device. There was a problem with it coming.

On the other hand, the latter bolt attachment/detachment transfer is carried out by standing on the upper mirror flange, connecting with the stud bolt head to rotate the stud bolt, and holding the removed stud bolt in the device as it is (through the screws formed in the device). ) and
It will be moved to a storage location by an overhead crane along with several stud bolts. However, this device does not have a mechanism to cancel the weight of the stud bolt when rotating the stud bolt. Therefore, a large torque is required to rotate the stud bolt, and the threads of the stud bolt wear out. Alternatively, there is a possibility that the end threads may be damaged. In addition, the device and stud bolt are connected by screwing the bolt into the screw hole in the center of the stud bolt head, and since the bolt is inside, a separate jig is required to connect the stud bolt. The work required a long time to remove the parts. moreover,
Since a screw is used in the structure for lifting the stud bolt, it is necessary to unwind the stud bolt to remove it from the device, which poses a problem in that this operation also takes a long time.

The object of the present invention is to provide a stud bolt and a fuselage flange (
It is an object of the present invention to provide a stud bolt attachment/detachment device that can simultaneously and efficiently remove or attach a plurality of stud bolts and transport them without damaging the thread threads.

[Means for solving problems]

In order to achieve the above object, the present invention provides a structure for canceling the dead weight of the stud bolt based on the cylinder structure in the frame placed on the bolt mounting part, and a structure located on the extension line of the center axis of the stud bolt. An intermittent impact force is applied to the stud bolt from a rotational drive mechanism attached to the frame, and a one-touch mechanism using a chuck is used for attaching and detaching the stud bolt.

Preferably, a plurality of the above-mentioned movable units are assembled into a frame to form an integral bar, so that a plurality of stud bolts can be handled at the same time.

[Effect]

When the stud bolt is removed, the cylinder device supplies pressure that cancels out the weight of the stud bolt and the movable part, thereby reducing the frictional force on the threaded portion of the stud bolt no matter where the stud bolt is located in the axial direction. Further, when the stud bolt is removed from the flange of the body, the weight of the stud bolt is not applied to the threads at the end, so the threads are not damaged, and the stud bolt can be installed in the same way. Furthermore, by switching the supply pressure to the cylinder device to a low pressure, the piston member returns to its original position, so there is no need to unwind the screw.

Since the rotating shaft and the movable shaft can separate the pulling force of the stud bolt by the piston member, the reaction force of the rotational torque from the rotational drive mechanism can be reduced. Further, by applying an intermittent impact force to the rotational drive mechanism, it is possible to give vibration to the stud bolt and relieve galling of the screw due to rust.

By configuring a chuck mechanism that opens and closes the stud bolt head with a lever or the like, the stud bolt and the device can be attached and detached with one touch.

By installing the above-described mechanism in the same frame in accordance with the arrangement of stud bolts, it becomes possible to handle multiple types of stud bolts at the same time.

C Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 8. This embodiment is for attaching and detaching stud bolts for tightening the reactor pressure vessel upper mirror of a boiling water reactor, and will be explained with reference to FIGS. 9 and 10 as well.

Figure 2 is a longitudinal sectional view showing the entire stud bolt attachment/detachment device, and Figure 2 is a plan view thereof. As shown in Figure 1,
This stud bolt attachment/detachment transfer device has a plurality of units 31 mounted on one frame 32 for removing and attaching stud bolts 3 projecting onto the flange la of the upper mirror 1 of the reactor pressure vessel.

FIG. 3 is an enlarged sectional view showing the configuration of one unit 31. An impact wrench 33 is provided at the upper end of the frame 32 as a rotational drive mechanism for applying intermittent impact force to the stud bolt 3 and rotating the stud bolt 3. This impact wrench 33 is located on an extension of the central axis of the stud bolt 3 and is provided to be able to rotate intermittently, and its rotational force is applied to a rotating shaft 34, which will be described later, which is arranged on an extension of the central axis of the stud bolt 3.
a, is transmitted to the top of the stud bolt 3 via the movable shaft 34b and the engagement wrench 35.

The rotating shaft 34a is connected to the impact wrench 3 via the joint 33a.
3, and is rotatably supported by the frame 32 via a bearing 33b. This rotating shaft 3
A movable shaft 34b can coaxially rotate integrally with the lower end of 4a,
Moreover, it is provided so as to be relatively slidable in the axial direction. That is, as shown in FIG. 4, the rotating shaft 34a and the movable shaft 34b are spline-coupled. The lower end of the movable shaft 34b is provided with a convex engagement wrench 35 that engages with an engagement recess 3d formed at the top of the stud bolt 3 shown in FIG. 5 to apply rotational force. Furthermore, a chuck 36 is provided on the outer circumferential side of the engagement wrench 35 of the movable shaft 34b to detachably grip and lift the outer circumference of the stud bolt 3. This chuck 36 has a split cylinder shape, and is divided into a plurality of parts (for example, three to five parts) in the circumferential direction. The component piece of this chuck 36 is slidable in the radial direction, and when moving in the radial direction, it engages with a large number of annular parallel grooves 3C formed on the outer peripheral surface of the top of the stud bolt 3, and the stud bolt 3 can be moved together in the axial direction for tightening.

A chuck driving member 37 for expanding and contracting the chuck is provided on the outer peripheral side of the chuck 36. That is, the chuck driving member 37 has a cylindrical shape, and has an uneven engaging portion 37a on the inner circumferential side thereof.
chuck 36 by sliding in the axial direction.
It engages with the uneven engaging portion 36a on the outer circumferential surface of and presses toward the diameter-reducing side or allows movement toward the diameter-expanding side.

Further, a piston member 38 is provided on the outer peripheral side of the movable shaft 34b mentioned above. This piston member 38 is connected to the movable shaft 34b via a bearing 39 so as to be relatively rotatable and integrally movable along the axial direction. This piston member 38 consists of a piston 38a and hollow piston rod parts 41a and 41b connected above and below the piston 38a,
It is held on the inner surface of a cylinder member fixed to the frame 32, for example, an air cylinder 40, and is slidable in the axial direction thereof. Then, the piston 38a can be pushed up by compressed air supplied from the air supply port 44 provided at the lower end of the air cylinder 40, thereby causing the movable shaft 3
Push-up force is also applied to 4b.

Furthermore, the aforementioned cha 2 is attached to the lower piston rod 41a.
A driving member 37 is fitted to be slidable in the axial direction, and the chuck driving member 37 is tightened in the axial direction, that is, by a lever that rotates around a bracket 42 protruding from the lower end of the piston rod 41a. It is possible to move in the direction.

In the above configuration, the procedure for removing the stud bolt 3 will be explained with reference to FIG. 3 and FIGS. 6 to 8.

First, lift the frame 32 using an overhead crane or the like,
Stud bolt 3 attached to the upper mirror of the reactor pressure vessel
Move up and remove the flange l of the upper mirror l, as shown in Figure 3.
Hang and place it on top a. In this case, the wrench 35 rides on the stud bolt 3, which pushes the piston member 3B upward via the movable shaft 34b,
A space is formed between 8a and the lower end surface of the air cylinder 40. At this time, the chuck 36 is in a released state.

Next, as shown in FIG. 6, lever 43 is pulled upward. As a result, the bracket 4 protruding from the cylinder 41
2 as a fulcrum, the chuck driving member 37 is pushed down, and the chuck 36 reduces its diameter via the engaging portions 36a and 37a and engages with the parallel groove portion 3c of the stud bolt 3, thereby engaging the stud bolt 3 and the wrench 35. be able to.

In this state, by supplying pressurized air from the air supply port 44 provided at the lower end of the air cylinder 40, the piston 3
Push 8a upward. In this case, the piston member 38
Since the movable shaft 34b and the movable shaft 34b are integrally connected in the axial direction, a pulling force is generated on the stud bolt 3 via the engagement wrench 35 and the chuck 36. At this time, the air pressure supplied to the air cylinder 40 is set to a value that generates a force that lifts the total weight of the movable parts such as the stud bolt 3, chuck 36, chuck drive member 37, movable shaft 34b, and piston rods 41a and 41b. do it.

If the impact wrench 33 is rotated intermittently with the stud bolt 3 pulled up, the fixed shaft 34a and the rotating shaft 34
An intermittent rotational force, that is, a rotational force accompanied by an impact force, is transmitted to the stud bolt 3 through the wrench 35 and the wrench 35, and the stud bolt 3 rotates. As the stud bolt 3 rotates, the stud bolt 3 begins to slide in the direction of being out of alignment as shown in FIG. 7, but the air supply port 4 of the air cylinder 40
By continuing to supply air at a constant pressure from 4, the movable part moves up and down at the same time as the stud bolt 3, and the weight of the stud bolt 3 is always canceled out. In this state, rotate further so that the stud bolt 3 connects to the flange 2a of the body 2.
When the stud bolt 3 and the movable part are removed from the threaded part 2b of the fuselage flange 2a, the stud bolt 3 and the movable part are supported by the frame 32 via the air cylinder 40, as shown in FIG. It is possible to prevent the weight of the stud bolt 3 from being applied to the threads at the ends of the threads, thereby preventing damage to the threads.

A plurality of target stud bolts 3 are extracted using the above-mentioned procedure, and while the stud bolts 3 are being gripped, the valve of the air supply port 44 is closed so that the air in the air cylinder 40 does not leak, and the entire stud bolt attachment/detachment transfer device is removed. be lifted up by an overhead crane and moved to a designated storage location. By mounting it on a predetermined storage rack at a storage location and releasing the pressurized air in the air cylinder 40, the upward force applied to the stud bolt 3 via the movable shaft 34b and the chuck 36 disappears. If the lever 43 is pushed down to move the chuck drive member 37 upward and the chuck 36 is released, the stud bolt attachment/detachment device is moved to the stud bolt 3.
You can simply remove the clause from the clause.

〔Effect of the invention〕

As described above, according to the present invention, by mechanically rotating the stud bolt, even in a highly radioactive area, for example,
The labor of the workers can be significantly improved. Further, a plurality of stud bolts can be handled at the same time without the need to change tools, etc., thereby reducing working time.

Further, by rotating the stud bolt while canceling its own weight, the rotational torque can be reduced, and the stud bolt and bolt attachment can also be prevented from being damaged by threads.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the stud bolt attachment/detachment device according to the present invention, FIG. 2 is a plan view of FIG. 1, and FIG.
The figure is an enlarged sectional view showing the main part of Fig. 1, - Fig. 4 is a cross-sectional view showing the state of connection between the rotary shaft and the movable shaft, Fig. 5 is a plan view of the top of the stud bolt, and Fig. 6 is an enlarged sectional view showing the main part of Fig. 1. The figure is an explanatory diagram showing the state in which the top of the stud bolt is gripped, Figure 7 is an explanatory diagram showing the state in which the stud bolt is being removed from the bolt installation part, and Figure 8 is the action explanatory diagram showing the state in which the stud bolt is being removed from the bolt installation part. Fig. 9 is a sectional view showing the reactor pressure vessel, and Fig. 1O is A of Fig. 8.
Figure 11 is an enlarged sectional view of the reactor building, Figure 12 is a sectional view of the reactor building.
FIG. 13 is an explanatory diagram showing a conventional bolt wrench for releasing a stud bolt, and FIG. 13 is an explanatory diagram of a conventional stud handling tool for removing, attaching, and transporting a stud bolt. 3... Stud bolt, 31... Movable unit, 32... Frame, 33...
・Impact wrench, 34a... Rotating shaft, 34
b...Movable shaft, 35...Engagement wrench,
36... Chuck, 37... Chuck driving member, 3B... Piston member, 40...
...Air cylinder, 41a, 41b...Piston rod, 42...Bracket, 43...
...Lever, 44...Air supply port. Agent Patent Attorney Masaru Nishimoto - Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (3)

[Claims] (1) A frame placed on a bolt attachment part into which a stud bolt is screwed with its top protruding, and a rotating shaft rotatably provided on the frame and located on the axial extension line of the stud bolt. and is connected to the rotating shaft so as to be coaxially rotatable and relatively slidable in the axial direction, and its tip engages with the engagement recess at the top of the stud bolt to apply rotational force to the stud bolt. A movable shaft that is a convex engagement wrench, a chuck that is expandably and retractably provided on the outer periphery of the engagement wrench of the movable shaft and that removably grips the outer periphery of the stud bolt, and a chuck that is provided on the outer periphery of the chuck. a chuck driving member that applies an expanding and contracting force to the chuck; a piston member that is integrally provided on the outer circumferential side of the movable shaft so as to be movable in the axial direction; and a piston member that is housed and held and fixed to the frame; a cylinder member that applies a moving force along the axial direction to the piston member; and a rotational drive mechanism that is attached to the frame and that can apply impact and rotational force to the stud bolt via the rotating shaft, movable shaft, and engagement wrench. A stud bolt attachment/detachment transfer device characterized by comprising: (2) Rotating shaft, movable shaft, chuck, chuck driving member,
The stud bolt attachment/detachment device according to claim 1, wherein a plurality of movable units for stud bolt attachment/detachment consisting of a piston member, a cylinder member, and a rotational drive mechanism are provided adjacently within one frame. (3) The chuck for gripping the stud bolt is of a split cylinder type, and the chuck driving member is attached to the piston member so as to be slidable along the axial direction, and tightens the chuck from the outer circumferential side by moving in the axial direction. The chuck drive member has a cylindrical structure having a tightening engagement portion, and the chuck driving member is slidable in the chuck tightening direction by a lever pivotally connected to the piston member. Stud bolt attachment/detachment transfer device.