JP7329177B2 - insertion light source - Google Patents

Description

The present invention comprises a first magnet row in which a large number of magnets are arranged in a row, a first magnet support to which the first magnet row is attached and supported, a large number of magnets arranged in a row, and a second magnet row facing the first magnet row across a gap; a second magnet support to which the second magnet row is attached and supported; and the first magnet support for changing the size of the gap. a gap drive mechanism for driving the body and/or the second magnet support in the direction in which the magnet rows face each other; A connecting beam, a second connecting beam integrally connected to the second magnet support via a second magnet support guide mechanism, and a driving interlock for connecting the gap drive mechanism and the magnet support. and an insertion device having a mechanism.

When an electron beam accelerated to near the speed of light in a vacuum is bent in a magnetic field, it emits synchrotron radiation in the tangential direction of the trajectory of the electron beam, which is called synchrotron radiation. Practical use of various technologies by installing a light source that generates such synchrotron radiation in the straight part of an electron storage ring (electron beam storage ring) and taking advantage of its characteristics such as high directivity, high intensity, and high polarization. Research is being conducted to Today's electron storage rings are equipped with multiple insertion sources (undulators), which are bright sources with higher beam currents and smaller beam cross-sections.

As such an insertion light source, for example, an insertion light source disclosed in Patent Document 1 below is known. This insertion light source has a configuration in which a first magnet row in which a large number of magnets are arranged in a row and a second magnet row in which a large number of magnets are arranged in a row face each other across a gap. Since the first magnet array and the second magnet array are sealed in a vacuum chamber, the magnet array (magnetic circuit) is arranged in the vacuum chamber, and then the chamber is evacuated by evacuating. .

However, when the pressure inside the tank drops, gas is generated from the permanent magnets (for example, Nd--Fe--B sintered magnets) that make up the magnet array and other parts inside the tank, preventing the degree of vacuum from increasing. There is Therefore, at the initial stage of evacuation, the temperature is raised to a predetermined temperature and a baking process is performed to degas. As a result, the magnet support that supports the array of magnets extends in the longitudinal direction due to thermal expansion, resulting in a difference in length between parts inside and outside the vacuum chamber. Therefore, the magnet support and the connecting beam are connected via a magnet support guide mechanism to absorb the length difference. This prevents the gap drive mechanism and drive interlocking mechanism from being affected by thermal expansion.

Specifically, a linear guide is used as such a magnet support guide mechanism. This linear guide employs a configuration in which a large number of balls roll on an endless track.

WO2018/143253A1

Since the linear guide described above employs a configuration in which a large number of balls roll on an endless track, the structure is complicated and the cost is high. In addition, due to the recent high demand in semiconductor manufacturing (equipment), there is also the problem that it is difficult to obtain and it takes a long time to deliver.

SUMMARY OF THE INVENTION An object of the present invention is to provide an insertion light source capable of reducing costs by adopting a simple magnet support guide mechanism.

In order to solve the above problems, the insertion light source according to the present invention includes:
a first magnet row in which a large number of magnets are arranged in a row;
a first magnet support to which the first magnet row is attached and supported;
a second magnet row in which a large number of magnets are arranged in a row and faces the first magnet row across a gap;
a second magnet support to which the second magnet row is attached and supported;
a gap drive mechanism for driving the first magnet support and/or the second magnet support in opposing magnet array directions to vary the size of the gap;
a first connecting beam integrally connected to the first magnet support via a first magnet support guide mechanism;
a second connecting beam integrally connected to the second magnet support via a second magnet support guide mechanism;
at least one of the first connecting beam and the second connecting beam, and a driving interlocking mechanism for connecting the gap driving mechanism;
The first magnet support guide mechanism and the second magnet support guide mechanism allow the movement of the first magnet support and the second magnet support in the direction along the magnet rows. The magnet support guide mechanism also
a movable guide portion attached to the first magnet support and the second magnet support;
a fixed guide part attached to the side of the first connecting beam and the second connecting beam;
a guide unit disposed between the movable guide portion and the fixed guide portion;
The guide unit is
A large number of rollers arranged side by side in the direction along the magnet row,
and a holder for supporting the roller.

The functions and effects of the inserted light source with this configuration are as follows. A first magnet support is integrally connected to the first connecting beam via a first magnet support guide mechanism and a second magnet support is integrally connected to the second connecting beam via a second magnet support guide mechanism. connected to The gap driving mechanism changes the size of the gap by driving at least one of the first connecting beam and the second connecting beam. Here, the first and second magnet support guide mechanisms include a movable guide portion attached to the first and second magnet support sides, a fixed guide portion attached to the first and second connecting beam sides, and the movable guide and a guide unit disposed between the portion and the fixed guide portion. Further, the guide unit includes a large number of rollers arranged in a direction along the magnet array and having a needle-like or cylindrical shape, for example, and a holder for supporting the rollers. That is, the magnet support body guide mechanism is realized with a simple configuration of the rollers and their holders. Such guide units are commercially available and are much cheaper and more readily available than the linear guides conventionally used. As a result, it is possible to provide an insertion light source capable of cost reduction.

The direction in which the magnet rows face each other depends on the manner in which the magnet rows are installed, and includes, for example, a vertical direction, a horizontal direction, and an arbitrary inclined direction. Moreover, the movement in the direction in which the magnet arrays face each other includes both the case where the magnet arrays approach and the case where they move away from each other.

Also, the first magnet support is integrally connected to the first connection beam via the first magnet support guide mechanism. A configuration in which another member is interposed is also included in the present invention. The present invention also includes a configuration in which another member is interposed between the first magnet support guide mechanism and the first connecting beam. The same is true for the second magnet support guide mechanism.

In the present invention, a guide concave portion formed in the movable guide portion and a guide convex portion formed in the fixed guide portion are provided, and the guide unit is provided between the guide concave portion and the guide convex portion. is preferred.

According to this configuration, the guide unit can be configured by inserting the guide protrusion between the guide recesses. In addition, the shape of a recessed part and a convex part is not limited to a specific shape.

The guide protrusion according to the present invention preferably includes a first horizontal surface, a second horizontal surface, and a vertical surface connecting the first horizontal surface and the second horizontal surface, and the guide unit is preferably provided on each of these three surfaces. .

With such a configuration, square recesses and protrusions are formed, and by arranging guide units on each of the three surfaces, smooth guiding can be achieved.

In the present invention, it is preferable that a spacer arranged on the surface side of the roller and a mechanism for adjusting the pressing force of the spacer against the roller are provided. With such a configuration, an appropriate pressing force can be applied to the rollers.

In the present invention, it is preferable that a threaded hole is formed in the guide recess, and the pressing force is adjusted by the amount of fastening of the screw to the threaded hole.

According to this configuration, the pressing force can be adjusted by rotating the screw. This allows the guide unit to operate properly.

FIG. 2 is a perspective view of the insertion light source according to the present embodiment as seen from the front side; Front view of insertion light source according to the present embodiment Side view of insertion light source according to the present embodiment FIG. 2 is a perspective view of the insertion light source according to the present embodiment as seen from the front side, and shows a state in which the vacuum chamber is removed; Partial enlarged view of FIG. Perspective view of magnet support guide mechanism Perspective view of magnet support guide mechanism (operation diagram) Exploded perspective view of the magnet support guide mechanism Side view of magnet support guide mechanism Front view of magnet support guide mechanism BB sectional view of FIG. AA sectional view of FIG. Appearance perspective view of guide unit

A preferred embodiment of an insertion light source according to the present invention will be described with reference to the drawings. FIG. 1 is a front perspective view of an insertion light source according to this embodiment. FIG. 2 is a front view. FIG. 3 is a side view. FIG. 4 is a perspective view of the front side with the vacuum chamber removed. 5 is a partially enlarged view of FIG. 4. FIG.

As shown in FIGS. 4 and 5, etc., the insertion light source has a gap between a first magnet row M1 in which a large number of magnets are arranged in a row and a second magnet row M2 in which a large number of magnets are arranged in a row. They face each other across δ. An electron beam passes through this gap space. As the magnet array, for example, in addition to the one cited in Patent Document 1, various configuration examples such as those disclosed in JP-A-2001-143899 and JP-A-2014-13658 are conceivable. Therefore, it is not limited to any particular magnet arrangement.

The first magnet array M1 is supported by the first magnet support 1 and the second magnet array M2 is supported by the second magnet support 2. As shown in FIG. For example, the individual magnets forming the first magnet row M1 are coupled to the first magnet support 1 by bolts or the like. The same applies to the second magnet row M2.

Also, the direction in which the first magnet row M1 and the second magnet row M2 face each other is the vertical direction, but the insertion light source is not limited to the above. It may have a combination of directions.

Note that the vacuum chamber 3 is supported on the base 10 by a support 600 . As also shown in FIG. 1, a support member 610 is provided on the support 600 to receive the lower portion of the vacuum chamber 3 . The support 600, the support member 610, and the vacuum chamber 3 are connected by mechanical means (for example, bolts and nuts) (not shown). Further, the support 600 is also coupled to the base 10 by suitable mechanical means (for example, bolts and nuts). Various modifications are possible for the support structure of the vacuum chamber 3 .

As shown in FIG. 3 , a connecting shaft 100 is attached to the top of the first magnet support 1 , and the upper end of the connecting shaft 100 is connected to a connecting plate 101 . As shown in FIG. 2, eight connecting shafts 100 are arranged along the left-right direction, and eight connecting plates 101 are also arranged. As shown in FIG. 3 and the like, two connecting shafts 100 are arranged along the front-rear direction when viewed from the front side, and these two connecting shafts 100 are connected by one connecting plate 101 . That is, in the present embodiment, a total of 16 connecting shafts 100 are arranged, and two each of the 16 connecting shafts 100 are connected by eight connecting plates 101 .

The connecting shaft 100 is composed of a plurality of parts rather than a single part. Figure 3, Figure 5
As can be seen from , it is composed of a plurality of shaft members and a plurality of parts such as flanges positioned at the ends of the shaft members. The specific configuration of the connecting shaft 100 is not limited to this embodiment, and various modifications are conceivable.

A first connection beam 103 is arranged above the connection shaft 100 . The first connecting beam 103 and the connecting plate 101 are connected by the magnet support guide mechanism 7 . This is provided in order to absorb the change when the length of the first magnet support 1 changes in the longitudinal direction due to thermal expansion. Therefore, the influence of thermal expansion is prevented from affecting the gap drive mechanism 50 and the drive interlocking mechanism, which will be described later. As described above, the first magnet support 1 and the first connection beam 103 are integrally connected via the magnet support guide mechanism 7 . When the first connecting beam 103 moves in the vertical direction (an example of the direction in which the magnet rows face each other; the same applies hereinafter), the first magnet support 1 also moves in the vertical direction together with it. The amount of vertical movement is the same. The mechanism for integrally connecting the first connecting beam 103 and the first magnet support 1 is not limited to the above, and various modifications are applicable. The details of the magnet support guide mechanism 7 will be described later.

The second magnet support 2 is also integrally connected to the second connection beam 203 via the connection shaft 200 , the connection plate 201 and the magnet support guide mechanism 7 . Since the configuration is the same as that of the first connecting beam 103, the description thereof is omitted. The same applies to the following description.

As shown in FIG. 1, the first connecting beam 103 has a body frame 103a having a rectangular parallelepiped shape extending in the left-right direction. Furthermore, two support frames 103b are connected to the rear side of the body frame 103a and extend along the front-rear direction when viewed from the front side.

<Gap drive mechanism>
A gap driving mechanism 50 for changing the size of the gap .delta. is provided at the rear upper portion of the insertion light source. The gap driving mechanism 50 is installed on the base 10 via a frame 500. As shown in FIG. The frame 500 has a rectangular parallelepiped shape with a rectangular cross section in the horizontal direction, and two frames 500 are provided. A mounting plate 501 is provided on the top of the frame 500, and the gap driving mechanism 50 is mounted thereon. As for the gap driving mechanism 50, the same mechanism as that disclosed in the above-mentioned Patent Document 1 can be adopted.

The gap drive mechanism 50 has a drive motor 51 and converters 52 , 53 , 54 . The conversion unit 52 converts the direction of drive transmission by 90 degrees. The conversion unit 53 converts the direction of drive transmission and branches left and right to transmit power. A pair of conversion units 54 are provided on the left and right, and convert horizontal driving to vertical driving. A specific configuration is performed by known mechanical elements such as bevel gears.

The conversion unit 54 converts the drive transmission in the vertical direction, and drives, for example, a ball screw mechanism (not shown) having a vertical axis. A ball screw mechanism has a well-known structure and is composed of a screw shaft portion and a nut portion.

By driving the ball screw mechanism, the screw shaft rotates and the nut can move up and down. Therefore, the first connecting beam 103 can be moved vertically. A support frame 103b is provided to move the first connecting beam 103 vertically (see FIG. 1). The rear side of the support frame 103b seen from the front side is attached to the front side of the frame 500 seen from the front side by two frame guide mechanisms 103c. The front side of the support frame 103b as viewed from the front side is attached to the first connecting beam 103 (see FIG. 3).

As described above, the frame guide mechanism 103c and the ball screw mechanism driven by the converting portion 54 correspond to a driving interlocking mechanism for connecting the first connecting beam 103 and the gap driving mechanism 50. FIG. By driving the drive motor 51, the first connecting beam 103 can be moved in the vertical direction, and the first magnet support 1 and the first magnet array M1 can be moved in the vertical direction. That is, the size of the gap δ can be changed.

The second connecting beam 203 located on the lower side can also be vertically moved by a gap driving mechanism (not shown) disposed on the lower side, and its configuration is basically the same as that of the first connecting beam 103 . Since it is the same as the case of , the explanation is omitted. By moving the first connecting beam 103 and the second connecting beam 203 in the vertical direction with the above configuration, the size of the gap δ can be changed. When the first connecting beam 103 and the second connecting beam 203 are moved toward each other, the gap δ becomes smaller, and when they are moved away from each other, the gap δ becomes larger.

<Magnet Support Guide Mechanism>
Next, a specific configuration of the magnet support guide mechanism 7 will be described. 6A and 6B are perspective views of the magnet support guide mechanism 7. FIG. 7 is an exploded perspective view of the magnet support guide mechanism 7. FIG. FIG. 8 is a side view. FIG. 9 is a front view. FIG. 10 is a vertical cross-sectional view taken along line BB of FIG. FIG. 11 is a cross-sectional view taken along line AA of FIG. FIG. 12 is an external perspective view of the guide unit. For convenience of drawing, parts other than the magnet support body guide mechanism 7 are generally omitted. The drawings shown in FIG. 6 and the like correspond to the partial enlarged view shown in FIG. 5, but the magnet support body guide mechanism 7 at other locations has the same structure. In addition, in FIG. 6 and the like, the second connecting beam 203 is shown as a rectangular plate for convenience of illustration. The first magnet support guide mechanism 7 is arranged on the first connection beam 103 side, and the second magnet support guide mechanism 7 is arranged on the second connection beam 203 side. 7 for explanation.

As shown in FIG. 6 and the like, the magnet support guide mechanism 7 includes a fixed guide portion 70A and a movable guide portion 70B. The fixed guide portion 70A is configured by the first block 70 . The movable guide portion 70B is composed of the second block 71 and the connecting plate 201. As shown in FIG. The first block 70 has a pair of left and right guide projections 700 . A guide recess 710 is formed in a state where the second block 71 and the connection plate 201 are combined. The connection between the second block 71 and the connecting plate 201 is performed by bolts 701 . The first block 70 is coupled to the second connecting beam 203 with bolts (not shown).

As shown in FIG. 9 and the like, the guide projection 700 has a first horizontal surface 700a, a second horizontal surface 700b, and a vertical surface 700c, thereby forming a projection. A first horizontal surface 201a is also formed on the connection plate 201 to face the first horizontal surface 700a. Similarly, the second block 71 is formed with a second horizontal surface 710b and a vertical surface 710c, and these and the first horizontal surface 201a form a guide recess 710. As shown in FIG. Note that the reference numerals in FIG. 9 show either one of the left-right symmetrical parts for the convenience of drawing notation.

In the above configuration, a space is formed between the guide protrusion 700 and the guide recess 710, and the guide unit 72 is arranged in the space. Specifically, the guide unit 72 is arranged between the first horizontal surface 700a and the first horizontal surface 201a, between the second horizontal surface 700b and the second horizontal surface 710b, and between the vertical surface 700c and the vertical surface 710c. That is, three guide units 72 are arranged between the guide convex portion 700 and the guide concave portion 710, and a total of six guide units 72 are arranged.

FIG. 12 is an external perspective view showing only the guide unit 72. As shown in FIG. The guide unit 72 is composed of a large number of rollers 720 and holders 721 that support the rollers 720 . As the guide unit 72, a flat cage manufactured by Nippon Thompson Co., Ltd. or a flat roller manufactured by THK Corporation can be used. However, the guide unit 72 according to the present invention is not limited to a specific structure or manufacturer. The roller 720 is formed in a needle-like or columnar shape.

A roller support portion 722 and a groove portion 723 formed along the longitudinal direction are integrally formed in the holder 721 . The roller 720 is formed in a cylindrical shape, and both ends thereof are supported by roller support portions 722 so as not to fall off. Further, the surfaces of the rollers 720 are supported in such a manner that they protrude slightly from the roller support portions 722 . Roller 720 is supported by holder 721 (roller support portion 722 and groove portion 723) so as to be freely rotatable.

As shown in FIG. 7 and the like, the spacer 73 is arranged on the roller 720 side of the guide unit 72 . The spacer 73 is made of a material such as steel and formed into a thin plate. A spacer 73 is arranged between the guide unit 72 and the guide recess 710 . Note that the material and thickness of the spacer 73 can be appropriately set.

The pressure of the guide unit 72 against the roller 720 can be adjusted by the set screw 74 via the spacer 73 . A side surface of the second block 71 is formed with a screw hole 711 through which a set screw 74 can be rotated. Thereby, it is possible to adjust the pressing force on the guide unit 72 positioned on the vertical surface 710c. The pressing force can be adjusted in the same manner for other guide units 72 as well. Appropriate guidance by the guide unit 72 can be performed by adjusting the pressing force.

In the cross-sectional view of FIG. 10, a set screw 74 that presses the spacer 73 positioned on the first horizontal surface 201a is illustrated. For this purpose, the second connecting plate 201 is formed with a screw hole 201b. In addition, although the spacer 73 is not provided on the second horizontal surface 710b, the spacer 73 may be arranged similarly to the other portions. The number of setscrews 74 to be arranged can be set appropriately.

As shown in FIG. 11, first block 70 is coupled to second connecting beam 203 by bolts 702 . The second connecting plate 201 is coupled to the second block 71 with bolts 701 . A spacer 73 arranged on the first horizontal surface 201a is pressed by a set screw 74. FIG.

The connecting shaft 200 is coupled to the second connecting plate 201 with bolts 703 . Since the connecting shaft 200 is actually composed of a plurality of parts, the part closest to the second connecting plate 201 is coupled to the second connecting plate 201 .

As described above, the vacuum chamber 3 is heated to a predetermined temperature and baked (heated to about 120° C.) at the initial stage of evacuation to degas. As a result, the first and second magnet supports 1 and 2 that support the first and second magnet rows M1 and M2 extend in the longitudinal direction due to thermal expansion. Therefore, the magnet support guide mechanism 7 is provided to absorb the difference in length caused by thermal expansion. This avoids problems such as breakage of parts. The guide unit 72 used in the present invention has a simple structure and has cost advantages over conventional linear guides.

FIG. 6B is a diagram showing a state in which the guide unit 72 is actually operated. As can be seen in comparison with FIG. 6A, it shows a state in which the movable guide portion 70B has moved relative to the fixed guide portion 70A. A specific amount of movement is 2 to 3 mm, and the guide unit 72 does not require a large amount of movement. A conventional linear guide has a ball that moves on an endless track and has a large movable range. However, in the case of the present invention, since the object is to absorb the change in length due to thermal expansion, for example, a thickness of about 10 mm is sufficient to guarantee operation.

Furthermore, when the guide unit 72 according to the present invention is used, the vertical elongation of the connecting plates 101 and 201 and the magnet supports 1 and 2 due to the magnetic attractive force is about 1 to 2 μm, so that the conventional linear guide can be used. As compared with the case where the thickness was about 10 μm, the stiffness was at least about 3 to 5 times higher.

<Another embodiment>
In the present embodiment, the guide projection has three surfaces, ie, the first horizontal surface, the second horizontal surface, and the vertical surface, but the guide projection may have two surfaces. For example, inclined surfaces may be combined to form a guide convex portion protruding in a V shape. In this case, a V-shaped guide unit may be used, or two flat plate-shaped guide units may be used in combination. Moreover, even when it is composed of three surfaces, it may be composed of a combination of inclined surfaces instead of horizontal or vertical surfaces.

In this embodiment, the guide recess is formed in the movable guide portion and the guide protrusion is formed in the fixed guide portion, but the guide protrusion is formed in the movable guide portion and the guide recess is formed in the fixed guide portion. may be configured.

M1 First magnet row M2 Second magnet row δ Gap 1 First magnet support 2 Second magnet support 3 Vacuum chamber 4 Pedestal 10 Base 100 Connecting shaft 101 Connecting plate 103 First connecting beam 200 Connecting shaft 201 Connecting plate 201a 1 horizontal surface 203 second connecting beam 50 gap drive mechanism 7 magnet support guide mechanism 70 first block 70A fixed guide portion 70B movable guide portion 700 guide convex portion 700a first horizontal surface 700b second horizontal surface 700c vertical surface 71 second block 710 guide Recess 710b Second horizontal surface 710c Vertical surface 72 Guide unit 720 Roller 721 Holder 722 Roller support 723 Groove 73 Spacer 74 Set screw

Claims (5)

a first magnet row in which a large number of magnets are arranged in a row;
a first magnet support to which the first magnet row is attached and supported;
a second magnet row in which a large number of magnets are arranged in a row and faces the first magnet row across a gap;
a second magnet support to which the second magnet row is attached and supported;
a gap drive mechanism for driving the first magnet support and/or the second magnet support in opposing magnet array directions to vary the size of the gap;
a first connecting beam integrally connected to the first magnet support via a first magnet support guide mechanism;
a second connecting beam integrally connected to the second magnet support via a second magnet support guide mechanism;
at least one of the first connecting beam and the second connecting beam, and a driving interlocking mechanism for connecting the gap driving mechanism;
The first magnet support guide mechanism and the second magnet support guide mechanism allow the movement of the first magnet support and the second magnet support in the direction along the magnet rows. The magnet support guide mechanism also
a movable guide portion attached to the first magnet support and the second magnet support;
a fixed guide part attached to the side of the first connecting beam and the second connecting beam;
a guide unit disposed between the movable guide portion and the fixed guide portion;
The guide unit is
A large number of rollers arranged side by side in the direction along the magnet row,
and a holder that supports the roller ,
a guide recess formed in the movable guide portion; and a guide protrusion inserted into the guide recess and formed in the fixed guide portion, wherein the guide unit is positioned between the guide recess and the guide protrusion. an insertion light source. a first magnet row in which a large number of magnets are arranged in a row;
a first magnet support to which the first magnet row is attached and supported;
a second magnet row in which a large number of magnets are arranged in a row and faces the first magnet row across a gap;
a second magnet support to which the second magnet row is attached and supported;
a gap drive mechanism for driving the first magnet support and/or the second magnet support in opposing magnet array directions to vary the size of the gap;
a first connecting beam integrally connected to the first magnet support via a first magnet support guide mechanism;
a second connecting beam integrally connected to the second magnet support via a second magnet support guide mechanism;
at least one of the first connecting beam and the second connecting beam, and a driving interlocking mechanism for connecting the gap driving mechanism;
The first magnet support guide mechanism and the second magnet support guide mechanism allow the movement of the first magnet support and the second magnet support in the direction along the magnet rows. The magnet support guide mechanism also
a movable guide portion attached to the first magnet support and the second magnet support;
a fixed guide part attached to the side of the first connecting beam and the second connecting beam;
a guide unit disposed between the movable guide portion and the fixed guide portion;
The guide unit is
A large number of rollers arranged side by side in the direction along the magnet row,
and a holder that supports the roller ,
a guide recess formed in the fixed guide portion; and a guide protrusion inserted into the guide recess and formed in the movable guide portion, wherein the guide unit is positioned between the guide recess and the guide protrusion. an insertion light source. 3. The guide projection is composed of a first horizontal surface, a second horizontal surface, and a vertical surface connecting the first horizontal surface and the second horizontal surface, and the guide unit is provided on each of these three surfaces. 3. The insertion light source according to 1 or 2 . 4. The insertion light source according to any one of claims 1 to 3, further comprising a spacer arranged on the surface side of the roller, and a mechanism for adjusting a pressing force of the spacer against the roller. 5. The insertion light source according to claim 4, wherein a threaded hole is formed in said guide recess, and said pressing force is adjusted according to the amount of fastening of a screw to said threaded hole.

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