JPH0143676Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a cleaning device for large nuts, and is particularly effective in cleaning the threaded portion of a nut that is threaded into a stud bolt used in a nuclear reactor pressure vessel. This invention relates to the structure of a portable cleaning device.

<Prior art and its problems> As shown in FIG. 1, the reactor pressure vessel is constructed by connecting the pressure vessel body 2 and the upper mirror 1, which is a closed head placed on the pressure vessel body 2, with stud bolts (hereinafter simply referred to as " (referred to as "bolts") 3 to seal the entire pressure vessel. Fig. 2 shows the details of the bolt connection, in which the bolt 3 is connected to the pressure vessel main body 2 through a threaded portion 3a that is threaded into the female threaded portion 2a' formed on the flange 2a of the main body 2, and protrudes from the upper surface of the main body 2. , on the other hand, an insertion hole 1 formed in the flange 1a of the upper mirror 1 and having a diameter larger than the outer diameter of the threaded portion 3b.
a' is inserted, and the threaded portion 3b at the other end protrudes outside the flange 1a. The nut 4 is attached to this threaded portion 3b.
are screwed together, and the bolt 3 firmly connects the upper mirror 1 and the main body 2 by the tightening force. This bolt 3 is attached to the nut 4 in the circumferential direction of the upper mirror 1 and the main body 2.
A large number (several dozen) are placed so close that they touch each other. For this purpose, the nut 4 is generally cylindrical in shape and is configured to rotate by a groove 4a formed in its upper end. Note that numeral 5 indicates a washer.

In order to confirm the safety of a nuclear reactor, the upper mirror 1 of the pressure vessel is removed and the interior inspected approximately once a year, but in this case, all of the dozens of bolts mentioned above must be removed. This bolt usually has a diameter of approx.
It is a large one, measuring 150 mm, approximately 1800 mm long, and weighing approximately 50 kg, and the nut that screws into it is also large. Bolts and nuts are rusted and covered with dust due to long-term operation of nuclear reactors, and are also contaminated with high concentrations of radioactivity.
The inventors have previously proposed a device that can efficiently and safely clean these bolts. However, the necessity of cleaning is exactly the same for nuts, and as a cleaning device for nuts of this type, the
It is known that the invention of No. 57-31990 is known.

However, in the invention of Utility Model Publication No. 56-33662, the cleaning device is fixed, and it is necessary to carry a cart carrying the nut to the device and align the vertical axis of the rotating brush with the axis of the nut. . In addition, although there is a hood for radioactive dust during cleaning, it is not designed to sufficiently suck out the dust that scatters from the brush when it enters and exits the nut. Utility Model Publication No. 57-31990 is an improved version of the above-mentioned device, in which the axis of the rotating brush is horizontal, and a housing with an opening/closing sheet made of a rectangular rubber plate prevents dust from scattering. same as,
The nut is placed horizontally on a cart and fed into the fixed device. For this reason, it is necessary to rotate the conveyor shaft of the nut with radioactive rust by 90 degrees and turn it sideways. Therefore, there has been a demand for a device that is portable, easy to handle, simple, and does not scatter dust without any handling work.

<Purpose of the invention> The purpose of this invention was constructed in view of the above-mentioned needs, and is to provide an apparatus that can easily handle and effectively clean large nuts.

<Summary of the Means> In short, this invention has a brush in an annular space between a driving device, a central shaft that is driven and rotates, and an outer cylinder, and an inner cylinder divided into at least two parts is located,
At the top of this inner cylinder, a taper part whose lower surface side is inclined in the axial direction of the central axis is directed, and a protrusion is provided on the inner surface of the outer cylinder opposite to this taper part, and the threaded part of the large nut is used to discharge powdery rust. This paper proposes a portable cleaning device for large nuts.

<Embodiment> FIG. 3 shows the entire nut cleaning device according to this invention, and shows the state before it is attached to a nut to be cleaned. In the figure, 11 is a motor serving as a drive device, and is connected to a central shaft 15 via a rotating shaft 11a. A flange portion 20 is provided at the upper end of the central shaft 15.
is formed, and an outer cylinder 13 is attached to this flange portion 20. Reference numeral 12 denotes a lid shaped like a tea caddy lid which is fitted onto the upper part of the nut 4 to be cleaned to fix the device, and is connected to the flange 36 on the shaft end side of the drive device. Reference numeral 19 denotes a bearing that supports the rotating shaft 11a in the lid body 12. Note that this lid body is provided with a hole 35 for air inflow.

Next, 14 is an inner cylinder, which has a central axis 15 and an outer cylinder 13.
It is located in an annular space between the two, and is divided into two or more parts. Reference numeral 16 denotes a brush attached to the outer circumferential surface of each divided piece of the inner cylinder, and the brush attachment portion 14a projects outward from the inner cylinder wall through its longitudinal groove-shaped opening 13a, as shown in FIG. As will be described later, when rotated, each divided piece moves outward due to centrifugal force, and the outer cylinder 1
The outer tube 13 is engaged with the opening 13a of the outer tube 13 at its edge, and the rotational force of the outer tube 13 is transmitted to the inner tube 14.

Next, the operating state of this device will be explained.

When attaching this device to the nut 4, each divided piece of the inner cylinder 14 is moved to the axis side of the central shaft 15, and the outer diameter including the brush 16 is adjusted.
D ₂ is smaller than the inner diameter D ₁ of the nut 4 to facilitate mounting of the device.

FIGS. 4 and 5 specifically show the movement of this divided piece. In the figure, the right half of the center line _l1 shows the state in which the nut is not installed as shown in FIG. 1, and the left half shows the state in which it is installed on the nut 4. First, as shown in FIG. 4, when the cleaning device (hereinafter simply referred to as the device) is not attached to the nut, that is, when the entire device is suspended by the handle 21, The divided pieces descend relative to the central axis 15 and the outer cylinder 13 due to their own weight. In this case, the tapered part 14b of the inverted trapezoidal conical surface formed on the divided pieces engages with the convex part 13b of the outer cylinder 13, and each divided piece moves toward the axis of the central shaft 15 as shown by arrow While contacting the edge of the opening 13a formed in the cylinder 13, a convex part 14c formed inside the inner cylinder forms a small diameter part 15 at the lower part of the central axis.
It is displaced toward the axis (indicated by arrow X) until it fits into the annular groove forming a. In this case, the convex portion 14c formed at the lower part of the divided piece is the small diameter portion 15a of the central shaft 15.
to go into.

Next, when the device is attached to the nut 4 placed on the nut holder 18, the roller 37 provided at the lower end of the divided piece is placed on the inner cylinder holder 33 formed in the nut holder 18. Since the center shaft 15 and the outer cylinder 13 are further lowered until the center shaft 15 is supported by the bearing 31, the position of the divided pieces rises relatively, and the convex portion 14c is aligned with the small diameter portion 1 of the center shaft 15.
Pushed by the upper tapered surface 15b of the annular groove 5a, the brush 16 moves in the Y direction, and engages with the threaded surface of the nut 4 to complete the setting. In this state, motor 1
1 to clean the inner surface of the nut 4. The inside of the nut 4 is almost completely sealed by the cover body 12 and the nut holder 18, and the removed rust and dust are sucked together with the air sucked in from the air hole 35 to the outside through the bottom hopper 34 without leaking to the outside. It is discharged.

<Effects> By implementing this idea, there is no leakage of radioactive powdery rust that occurs during nut cleaning, and the centering and mounting of the device on the nut is automatically facilitated, making nut cleaning effective and safe. can be done.

In addition, the device is portable, and the divided pieces of the inner cylinder with the brush attached can be extended or retracted from the axis side, making it easy to clean the threaded part of the nut. All you have to do is lower it and place it on the nut, and to remove it, just lift the device with the handle 21.

In addition, the nut receiving stand is provided with a plurality of recesses for receiving nuts, and the nut is placed in each recess, and the device is simply hung by the handle 21 and placed on the nut to be fitted with the nut. When removing the nut, all you have to do is lift the device, and the nut cleaning work can be done efficiently and quickly.

[Brief explanation of the drawing]

Figure 1 is a partial cross-sectional view of the reactor pressure vessel, Figure 2 is an enlarged view of part A in Figure 1, Figure 3 is a cross-sectional view of the device according to this invention, and Figure 4 shows the operating state of this device. 5 is a sectional view taken along line A--A in FIG. 4. 4... Nut, 11... Drive device, 13... Outer cylinder, 13b... Convex portion, 14... Inner cylinder, 14b...
Tapered part, 14c... Convex part, 15... Central axis, 1
5b... Central shaft taper portion, 16... Brush.

Claims (1)

[Scope of utility model registration request] The shaft of the drive device 11 is used to clean the threaded part of a large nut that is placed with its axis vertically on a nut holder that is equipped with a device that sucks dust generated by a cylindrical rotating body that has a brush on its outer circumferential surface. A lid body 12 in the shape of a tea caddy lid, which is fixedly connected to a flange 36 provided on the end side and whose lower part engages with the upper part of the nut during cleaning;
A central shaft 15 rotationally driven by the drive device 11
and an outer cylinder 13 that surrounds and connects this central axis and rotates together, and a brush attachment part 14 that contacts the edge of a vertically groove-shaped opening 13a provided in the outer cylinder 13.
an inner cylinder 14 which is divided into two or more parts and whose axis is concentric with the central axis 15 is provided in the outer cylinder 13, and a tapered part 14b having an inverted trapezoidal conical surface is provided in the upper part of the inner cylinder,
When the drive device 11 is lifted up by the handle 21, it slides into contact with the tapered portion 14b, and the brush 16 is attached to the nut 4.
A convex part 13b is provided on the inner surface of the outer cylinder 13 to separate it from the threaded part, and when the drive device 11 is suspended, the upper tapered surface 15b of the annular groove formed by the small diameter part 15a provided at the lower part of the central shaft 15. Convex portion 1 that makes sliding contact and displaces the inner cylinder 14 radially outward of the central axis 15 and brings the brush 16 into contact with the thread of the nut 4
4c is provided on the inner surface of the inner cylinder 14.