JPH0435102Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is useful for example in nuclear power plants with boiling water reactors (BWRs), where nuclear fuel assemblies and channels are used when replacing or inspecting reactor nuclear fuel. This invention relates to a bolt wrench for operating and removing fastener bolts and the like used for fastening boxes from a remote location.

(Prior Art) As shown in Figure 6, the nuclear fuel assembly F of the boiling water light water reactor (BWR) described above has a primary cooling water flowing through the nuclear fuel body (a combination of several dozen fuel rods) A. Rectangular cylindrical channel box B for promoting contact, guiding nuclear fuel control rods, and protecting nuclear fuel assemblies
Both are fixed by screwing with one fastener bolt C. For example, approximately 760 nuclear fuel assemblies F are used in a 1,000,000 kW class nuclear reactor, but during fuel exchange once a year, about 200 spent nuclear fuel assemblies, which is about 1/4 of these, are used. has been replaced. Normally, the spent nuclear fuel assembly F is taken out of the reactor and transferred to the spent fuel pool, where the fastener bolt C is removed and the nuclear fuel assembly F is attached to the nuclear fuel body A and the channel box B using a special jig. After being separated,
It is sent to each processing step. Such handling of spent nuclear fuel is carried out underwater for radiation shielding and cooling of the nuclear fuel body A.

By the way, as shown in FIG. 7, the fastener bolt C mainly consists of a bolt body 41 and a washer 4.
2, the bolt body 41 is formed with a head 41a having a spline and an annular groove 41b, a bolt neck part 41c, and a threaded part 41d in this order, and the washer 42 has a flat washer part 42a and a lower part thereof. A pair of side plate portions 4 are bent at right angles and are orthogonal to each other.
2c, and the bolt body 41
It is loosely fitted into the bolt neck portion 41c to prevent it from falling off. As shown in FIG. 6, with the side plate portion 42c of the washer 42 attached to the corner portion of the channel box B, the threaded portion 41d of the bolt 41 passes through the clip of the channel box B to the nuclear fuel assembly A. It is screwed into the upper screw hole.

By the way, as a general jig used for removing the fastener bolt C from the spent nuclear fuel assembly F, there has conventionally been a bolt wrench 51 as shown in FIG. This has a total length of 4m
The operating rod 52 has an operating handle 52a at the upper end and a cylindrical socket trench body 52b with an open bottom end, and is attached around the socket trench body 52b and has a protrusion at the lower end. It is provided with a leaf spring 55 having a shape 55a, a cylindrical cover body 53 for housing an operating rod 52, and a guide member 54, and is normally used as follows.

A worker lowers the lower end of the bolt wrench 51 onto the nuclear fuel assembly F below the water surface from the work floor above the spent fuel pool, and as shown in FIG.
Align the guide member 54 with the outer peripheral surface of the corner part of the channel box B, and then tighten the fastener bolt C.
A socket trench body 52b (having a spline corresponding to the bolt head 41a formed on the inner peripheral surface) at the lower end of the operating rod 52 is fitted into the head 41a.

In this state, the bolt 41 is loosened and removed by rotating the handle 52a, but at the same time, the socket trench body 52b moves upward with respect to the cover body 53 together with the operating rod 52, and the protrusion 55a of the leaf spring 55 is removed. The bolt protrudes inside the socket trench body 52b along the tapered hole 56 provided at the lower end of the cover body 53, fits into the annular groove 41b of the bolt head 41a, and grips the bolt 41, so it can be moved to a predetermined location. Can be carried.

(Problems to be Solved by the Invention) The conventional bolt wrench 51 described above has the following problems. That is, - When the distance from the operator's operating position to the fastener bolt C of the nuclear fuel assembly F becomes large (for example, 5 m or more), the bolt wrench 51 cannot reach and the fastener bolt C cannot be removed.

Therefore, in order to remove the fastener bolt C from the nuclear fuel assembly F, it must be temporarily stored in a fuel rack in the spent fuel pool (at this time, the upper end of the nuclear fuel assembly F is about 7 m below the water surface). It is necessary to move the nuclear fuel assemblies F one by one onto a preparation machine in shallow water. For this reason, there are many opportunities to move the nuclear fuel assembly F and the nuclear fuel body B, which increases the risk of damaging them, increases the number of workers required, takes longer working hours, and exposes workers to radiation. There are problems such as increased radiation dose.

On the other hand, it is conceivable to extend the operation rod 52 and cover body 53 of the conventional bolt wrench 51 described above and change the structure so that the socket trench body 52b at the lower end reaches the target bolt, but it is possible to leave the conventional structure unchanged. Even if the overall length is increased, it will not become practical. In other words, the bolt wrench 51 has a shaft portion 5 in consideration of operability, etc.
2 and 53 are made thinner to reduce weight, and the structure is fragile, so if they are extended further, the shaft parts 52 and 53 will break under their own weight when carrying the bolt wrench 51 or handling it before work. There is a risk that it may become bent and become inoperable. Also,
There were also problems in the following points.

- Each time the plate spring 55 is used, the protrusion 55a of the plate spring 55 comes into sliding contact with the fastener bolt C, and the plate spring 55
Since the thickness of the protrusion 55a is thin, the protrusion 55a wears out in a short period of time and becomes unusable, requiring frequent replacement.

- It was difficult to check whether the fastener bolt C was securely grasped from the operator's operating position, and if the bolt was moved with an incomplete grasp, there was a risk of the fastener bolt C falling during movement. .

This idea was created in consideration of the above points, and from a structural standpoint, it can be considerably longer than conventional bolt wrenches, and it is possible to remove bolts in positions that cannot be removed with conventional bolt wrenches. The present invention aims to provide a long type bolt wrench that can be divided into short lengths for easy portability when not used for work, has excellent durability, and can be used for a long period of time.

(Means for Solving the Problems) In order to achieve the above-mentioned purpose, the gist of this invention is to provide a socket trench body with an opening at the tip and a spline carved on the inner circumferential surface for rotational operation. an operating rod having a handle at its base end and consisting of a plurality of connectable rod parts, a locking claw pivoted around the socket trench body with a claw part protruding toward the distal end, and an opening at the distal end. It has a tapered hole in which the inner diameter gradually decreases toward the tip.
The outer cylinder is disposed around the operating rod so as to be movable in the axial direction within a certain range and rotatable relative to the operating rod, is biased toward the tip via a spring, and is made up of a plurality of connectable outer cylindrical parts. A cylinder, an operating lever attached near the base end of the operating rod to move the outer cylinder in the axial direction with respect to the operating rod, and a guide fixed to the distal end of the outer cylinder. That's true.

(Function) According to the bolt wrench of this invention, when removing a bolt located far from the operator's operating position and moving it to another location, the socket trench body at the tip of the operating rod is positioned by the guide tool. By fitting the target bolt head and moving the outer cylinder in the axial direction against the spring using the operating lever, the bolt head can be gripped by multiple locking claws.
Here, by rotating the handle, the bolt can be removed while grasping it, so the removed bolt can be moved to a predetermined location. In addition, by moving the outer cylinder in the direction in which the spring is biased by the operation lever,
The bolt head gripped by the plurality of locking pawls is released, and the bolt is released. Furthermore, by dividing the operating rod and outer cylinder into multiple parts, the length of each divided part can be shortened, making it easier to carry and handle. Since the length can be extended, it is possible to remove or install bolts in places that cannot be reached with a conventional bolt wrench.

(Example) Hereinafter, an example of the bolt wrench of this invention will be described based on the drawings.

FIG. 1 is a longitudinal sectional view showing a bolt wrench for attaching and detaching fastener bolts of a nuclear fuel assembly.

1 is a bolt wrench, from the tip side, the operating part 1a,
The bolt wrench 1 is divided into three connectable parts: an intermediate part 1b and an operating part 1c, and in this embodiment, the total length of the bolt wrench 1 is about 10 m.

Reference numeral 2 designates an operating rod, and the tip of the rod 2 is provided with a cylindrical socket trench body 4 with both ends open, and the base end of the rod 2 is provided with a handle 21 for rotational operation.

3 is an outer cylinder, which is movable in the axial direction within a certain range and rotatable relative to the operating rod 2;
It is arranged around Rod 2.

The operating rod 2 and the outer cylinder 3 are each divided into three connectable sections corresponding to the operating section 1a, intermediate section 1b, and operating section 1c of the bolt wrench 1.

Further, the corresponding connection points of each of the divided rod portions 2' are respectively formed into a convex fitting portion 2a having a rectangular cross section and a concave fitting groove 2b into which the fitting portion 2a can be fitted. , a connection cap nut 3a and a threaded portion 3 into which the cap nut 3a is screwed are provided at the corresponding connection points of each of the divided outer cylinder portions 3'.
b is provided. Furthermore, the intermediate portions of each split rod portion 2' are formed into sealed hollow portions 2c, 2d, and 2e, respectively, to generate buoyancy and allow the bolt wrench 1 to move when working in a spent fuel pool under water. It has the effect of reducing weight.

Next, the tip of the bolt wrench 1 (operating part 1
The structure of a) will be explained in detail.

The socket trench body 4 has a spline 4a cut into its inner circumferential surface, which can fit into the head 41a of the fastener bolt C.

Reference numeral 5 denotes locking claws, which are made of a thick metal member, and a plurality of locking claws 5 are arranged around the socket trench body 4, with the claw portion 5a at the tip protruding from the socket trench body 4, so that the locking claws 5 can be opened and closed freely. When the locking claws 5 are closed, the claws 5a fit into the annular grooves 41b of the fastener bolt C, and the fastener bolt C
I'm starting to grasp it. Further, a spring 5b is interposed in the intermediate portion of each locking pawl 5 to bias the pawl portion 5a outward (in the opening direction).

6a is a bearing sleeve rotatably mounted around the operating rod 2; 6b is a support sleeve slidably mounted around the outer cylinder 3 in the axial direction; the support sleeve 6b is attached to the bearing sleeve 6a; They are integrally connected via support bolts 6c. And between the bearing sleeve 6a and the protrusion 3c in the outer cylinder 3,
A coil spring 3s is interposed, and the outer cylinder 3 is biased toward the tip side with respect to the operating rod 2 by the coil spring 3s.

Reference numeral 7 denotes a mandrel, whose distal end is fitted into the socket trench body 4 at the axial center on the distal end side of the operating rod 2 so as to be movable in the axial direction, and is biased toward the distal end by a coil spring 7a. In the normal state, the tip of the mandrel 7 substantially coincides with the tip of the socket trench body 4.

Reference numeral 9 denotes a tapered hole formed in the opening at the distal end of the outer cylinder 3, and the inner diameter of the tapered hole 9 gradually decreases toward the distal end, so that the outer cylinder 3 is gradually moved to its base against the coil spring 3s. When moved toward the end, the tapered hole portion 9 presses the vicinity of the claw portion 5a of the locking pawl 5 inward, thereby closing the locking pawl 5. 10 is a guide tool, and in this embodiment, the nuclear fuel assembly F
The sleeve is a sleeve with a rectangular opening cross section that can be inserted into the veil A1 (see FIG. 6), and the tip side thereof is formed into a tupular shape with the opening cross section gradually widening. The guide tool 10 is disposed at the tip of the outer tube 3 via a support tool 10a. The positional relationship between the guide tool 10 and the socket trench body 4 is as follows:
With the guide tool 10 fitted into the veil A1 of the nuclear fuel assembly F, the head 41 of the fastener bolt C is
The socket trench body 4 is set to fit into the hole a. Reference numeral 11 denotes a display mechanism that displays the state in which the locking claw 5 has gripped the head 41a of the fastener bolt C, and a display plate 12 whose surface is colored is arranged between a horizontal position and a vertical position via a mounting member 12a. The support sleeve 6b is rotatably attached to the base end side of the support sleeve 6b. Further, one end of one of the pair of operating rods 11a for deploying the display board 12 is fixed to the support 10a of the guide tool 10, and one end is pivotally supported on the mounting member 12a of the display board 12. The other operating rod 11b connects the elongated hole 11d to this elongated hole 11.
It is connected to the other end of the operating rod 11a through a pin 11c loosely inserted into the operating rod 11a so as to be movable within a certain range. Further, a coil spring 11e is attached to the operating rod 11b, and urges the operating rod 11b in a direction in which the display plate 12 is expanded to a horizontal position.

8 is a lock lever with a beak-shaped tip.
This lock lever 8 passes through an insertion hole 8a formed in the support sleeve 6b and the outer cylinder 3, is pivoted to the distal end side of the support sleeve 6b, and has its base end attached to the distal end inside the outer cylinder 3. It comes into contact with the engaging portion 7b, and its tip is normally engaged with the tip protruding portion 11f of the operating rod 11b.

Next, the base end part of the bolt wrench 1 (operating part 1
The structure of c) will be explained in detail.

22 is a support tube with an open end;
2 is arranged on the proximal end side of the operating rod 2 so that a part of the rod 2 protrudes outward so as to be relatively rotatable, and the handle 21 for rotational operation is integrated with the proximal end protrusion of the rod 2. Rotatably mounted.

The proximal end of the outer cylinder 3 is fitted into the distal end of the support cylinder 22 so as to be slidable in the axial direction.
A coil spring 3p is interposed between the support tube 22 and the coil spring 3s, and urges the outer tube 3 toward the tip of the operating rod 2 together with the coil spring 3s. Reference numeral 22b denotes a grip portion fixedly provided on the distal end side of the support tube 22. Reference numeral 23 denotes an operating lever for moving the outer cylinder 3 toward the proximal end side with respect to the operating rod 2. This operating lever 23 has pins 24a, 24b and a connecting tool attached to a support ring body 24 fixed to the middle part of the support cylinder 22. It is pivotally connected via 24c so as to be swingable.

Further, as shown in FIG. 2, the distal end side mounting portion of the operation lever 23 is formed in opposing frames 23c that can hold the outer tube 3 from both sides, and has an insertion hole bored on both sides of the support tube 22. The frame 23c and the outer cylinder 3 are connected by a support bolt 23d passing through the frame 23b.
are connected. In this way, by swinging the operating lever 23 toward the distal end using the pin 24b as a fulcrum, the outer cylinder 3 is moved toward the proximal end with respect to the operating rod 2 against the coil springs 3s and 3p. It is configured.

Further, the operating lever 23 is provided with the operating lever 23 at the position where the outer cylinder 3 is moved to the proximal end side and at the original position.
A lashing mechanism 25 is provided to secure the . This lashing mechanism 25 is disposed movably along the operating lever 23, has a ring portion 26b in the middle through which the outer cylinder 3 is inserted, and has an engagement piece 2 at the tip.
6a, and this engaging member 26.
The trigger cover frame 28 is rotatably connected to the base end of the trigger cover frame 28.
The trigger 27 is rotatably supported on the support ring body 24, and the engagement member 26 is engaged with two engagement grooves 22d and 22e in which an engagement piece 26a formed on the support ring body 24 can be engaged and detached. It consists of a spring 29 that biases the trigger 27 in the direction in which the piece 26a fits into the engagement groove 22d or 22e.

Next, using the bolt wrench 1 configured as described above to remove the fastener bolt C of the nuclear fuel assembly F as an example, the manner in which it is used will be described.

(1) As shown in Figure 5, suspend the base end of the bolt wrench 1 at an appropriate position from a suspension wire such as an auxiliary crane via a shock absorber G equipped with a spring, and remove the nuclear fuel in the spent fuel pool. Lower it above assembly F.

(2) Attach the tip of the guide tool 10 of the bolt wrench 1 to
Insert into veil A1. In this state, the socket trench body 4 at the tip of the operating rod 2 is positioned on the head 41a of the fastener bolt C.

(3) By lowering the bolt wrench 1 further, the socket trench body 4 is attached to the fastener bolt C.
is fitted into the head 41a of the head 41a. Note that if you push down the bolt wrench 1 while holding the hanging wire in place, the buffer G will extend and the bolt wrench 1 can be moved within a certain range, so this work and the work in (2) above can be completed. It can be done easily. In addition, since the claw portion 5a at the tip of the engagement claw 5 is housed in the outer cylinder 3, when lowering the bolt wrench 1, the claw portion 5a may be damaged, or conversely, something may be damaged by the claw portion 5a. Never. In this way,
When the socket trench body 4 is fitted into the head 41a of the fastener bolt C, the mandrel 7 is pushed up by the head 41a against the spring 7a,
In conjunction with this, the sleeve 7b rotates the lock lever 8 (clockwise in FIG. 1), so that the engagement with the protrusion 11f of the operating rod 11b is released.

(4) Next, pull the trigger 28 of the operating lever 23,
The engagement piece 26a is released from one engagement groove 22d to release the engagement, and the operating lever 23 is swung toward the distal end to move the outer cylinder 3 toward the proximal end with respect to the operating rod 2. At this time, the tapered hole 9 at the tip of the outer cylinder 3 pushes the claw 5a of the locking claw 5 inward, so the claw 5a fits into the annular groove 41b of the fastener bolt C and grips the bolt C. (See Figure 3).

Moreover, when the outer cylinder 3 is moved, the support tool 10a
Since operation 11a also moves to the proximal side, the above (3)
The operating rod 11b, which has been disengaged from the lock lever 8, is pushed up by the biasing force of the coil spring 11e, and the display plate 12 is expanded to a horizontal position.
It is displayed that the locking claw 5 has gripped the fastener bolt C. Furthermore, by releasing the trigger 28 with the display board 12 displayed, the coil spring 2
3f, the engagement piece 26a at the tip of the engagement member 26
is inserted into the other engaging groove 22c, and the operating lever 2
Since the movement of the fastener bolt C is locked, the locking pawl 5 will not open inadvertently and release the fastener bolt C.

(5) In this state, when the operating rod 2 is rotated using the handle 21, the fastener bolt C is rotated and loosened through the socket trench body 4, so that the fastener bolt C can be removed from the nuclear fuel assembly F. Furthermore, as described above, since the bolt head 41a is completely gripped by the locking pawl 5, the fastener bolt C will not be accidentally dropped even after it is removed.

(6) Next, move the tip of the bolt wrench 1 that is gripping the fastener bolt C to the bolt collection location in the fuel pool, open the locking pawl 5 here, and release the fastener bolt C. Note that the operation for releasing the locking pawl 5 is to operate the operation lever 2 in the opposite manner to (4) above.
With the trigger 28 of No. 3 pulled, the operating lever 23
The outer cylinder 3 may be moved toward the distal end with respect to the operating rod 2 by swinging the outer cylinder 3 to its original position.

By the way, the display plate 12 of the display mechanism 11
is the head 41a of the fastener bolt C in (3) above.
When the socket trench body 4 is fitted into the fastener bolt C and the locking pawl 5 grasps it in the above (4), it will unfold horizontally for the first time and face the operator, but the socket trench body 4 will not be completely attached to the fastener bolt C. If you perform the gripping operation in (4) above in a state where they are not mated, resulting in a so-called empty grip state, the display plate 12 will not rotate and will remain in the vertical position, as shown in Figure 4. be. This is because the mandrel 7 is not pushed up by the head 41a of the fastener bolt C.
Since the lock lever 8 locks the movement of the operating rod 11b, even if the operating rod 11a is moved to the base end side together with the outer cylinder 3, the pin 11c is locked in the elongated hole 11d.
This is because the operating rod 11b is not pushed up by merely moving inside.

After completing the work, you can divide the bolt wrench 1 into three parts for convenient carrying.
Since the structure and dimensions of each connecting part of this bolt wrench 1 are common, for example, the operating part 1a and the operating part 1c can be directly connected to create a short wrench with a length of about 6 m, or conversely, multiple intermediate parts 1b can be connected. It is also possible to use a longer wrench.

The bolt wrench of this invention can be used not only for removing the fastener bolt C of the nuclear fuel assembly F described in the above embodiment, but also as a wrench for attaching and detaching various bolts that are out of reach of the worker. I can do it.

(Effects of the invention) Since the bolt wrench of this invention is constructed as described above, it has the following effects.

(a) Since it is structurally much longer than a conventional bolt wrench, it is possible to attach and detach bolts in positions that cannot be attached or detached with a conventional bolt wrench. Therefore, even if the nuclear fuel assembly is in the fuel rack of the spent fuel pool, the fastener bolt can be removed without moving it to a preparation machine in shallow water. These injuries are prevented by reducing the number of moves required, as well as reducing the number of workers, their working hours, and their exposure lines.

(b) The locking pawl is structurally stronger and more durable than the conventional plate spring-like locking pawl, and can be used for a long period of time.

(c) Since it can be divided into short pieces when not being used for work, it is easy to handle, and it does not bend under its own weight even when laid down, so no excessive force is applied during inspection or transportation, making it less likely to break down.

(d) As shown in the example, by providing a sealed hollow part in the operating rod of the bolt wrench,
It creates buoyancy in the water, making it easier to maneuver.

(e) As shown in the example, if a display mechanism is provided that displays the state in which the socket trench body is fitted to the bolt head and the locking pawl has completely gripped the bolt head, the operator can easily adjust the operating position. Since this can be visually confirmed, it is possible to reliably prevent operational errors.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the bolt wrench of this invention. Figure 1 is a longitudinal sectional view showing the overall structure, Figure 2 is a cross sectional view of the operating section, and Figure 3 is a fastener bolt. FIG. 4 is a vertical cross-sectional view showing the bolt wrench in a gripped state, FIG. 4 is a vertical cross-sectional view showing the bolt wrench in an empty grip state, and FIG. Fig. 6 is a perspective view showing a nuclear fuel assembly, Fig. 7 is a front view showing a part of a fastener bolt in cross section, and Fig. 8 is a vertical sectional view showing a conventional bolt wrench and a guide member showing its usage state. FIG. 1...Bolt wrench, 1a...Moving part, 1b...
...middle part, 1c...operation section, 2...operation rod,
3... Outer cylinder, 4... Socket trench body, 5... Locking claw, 7... Mandrel, 10... Guide tool, 11...
Display mechanism, 12... Display board, 21... Handle,
23... Operating lever, C... Fastener bolt,
F...Nuclear fuel assembly.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A socket trench body with an open tip and a spline cut on the inner peripheral surface, a handle for rotational operation at the base end, and a plurality of connectable rods. a locking pawl that is pivoted around the socket trench body so that the pawl protrudes toward the distal end so as to be freely openable and closable; and a tapered hole whose inner diameter gradually decreases toward the distal end within the distal opening. a plurality of external cylindrical parts, which are disposed around the operating rod so as to be movable in the axial direction within a certain range and rotatable relative to the operating rod, are biased toward the distal end via a spring, and are connectable; an outer cylinder consisting of an outer cylinder; attached near the proximal end of the operating rod;
A bolt wrench comprising: an operating lever for moving the outer cylinder in the axial direction with respect to the operating rod; and a guide tool fixed to the tip of the outer cylinder. (2) The bolt wrench according to claim 1, wherein a display mechanism is provided at the tip of the outer cylinder to display a state in which the locking pawl is gripping the bolt head.