JP2022076293A - Holding mechanism of steel pipe pole - Google Patents

Abstract

To extend a steel pipe pole in an upright posture via a screw joint and improve workability in assembling it into an underground hole.SOLUTION: When a steel pipe pole in an upright posture having a screw joint at an upper end and a lower end is extended utilizing an underground hole, a holding mechanism of the steel pipe pole holds the steel pipe pole situated at a lower side in a state of being suspended in the underground hole, a taper surface is formed on an outer peripheral surface of the screw joint provided at the lower end of the steel pipe pole and the holding mechanism comprises an openable type support frame having an opening into which the steel pipe pole can be inserted and a plurality of support pieces projecting toward the steel pipe pole inserted into the opening and having a placement surface on which the taper surface of the screw joint is placed.SELECTED DRAWING: Figure 4

Description

The present invention relates to a holding mechanism for a steel pipe column used when adding a steel pipe column in an upright posture via a screw joint.

Conventionally, a steel pipe column equipped with a screw joint is added in an upright position to construct a structural column having a desired member length, and when it is built into the underground hole, the lower steel pipe inserted into the underground hole is constructed. In many cases, a steel pipe column joining device having both a function of holding a column and a function of rotating an upper steel pipe column added to the lower steel pipe column is used.

For example, Patent Document 1 discloses a method of adding a steel pipe column having a female threaded portion at the upper end and a male threaded portion at the lower end by using a joining device provided with a holding device and a tightening device. ing. Specifically, a pair of rectangular keys in a plan view are formed on the outer peripheral surface of the steel pipe column near the upper end, and the lower steel pipe column inserted into the mine of the ground is held by the holding device using these keys. do.

The holding device includes a key receiving portion in which a key groove into which a key is fitted is formed, and a base in which the key receiving portion is provided on the upper surface. It is installed on the ground in this way. As a result, the lower steel pipe column is supported by the holding device by inserting a pair of keys into the keyway of the key receiving part while inserting the circular hole of the base and inserting it into the mine of the ground, and also rotates. It is said to be stopped.

On the other hand, the tightening device is provided above the holding device and includes a rotating mechanism for rotating the upper steel pipe column added to the steel pipe column supported by the holding device. Therefore, the male threaded portion of the upper steel pipe column is inserted into the female threaded portion of the lower steel pipe column held by the holding device, and the upper steel pipe column is rotated by the rotation mechanism in this state. Then, the male threaded portion of the upper steel pipe column is tightened to the female threaded portion of the lower steel pipe column, and both are joined.

JP-A-2015-140548

As disclosed in Patent Document 1, when a pair of keys are attached to a steel pipe column and the steel pipe column is held by a holding device using this key, a welding fixing means is generally adopted as the key attaching means. Will be done. However, it is known that when a pair of keys is fixed to the outer peripheral surface of a joint portion having a female threaded portion on the inner peripheral surface, thermal deformation occurs so that the male threaded portion cannot be screwed into the female threaded portion of the steel pipe column. ..

Therefore, when fixing the pair of keys, the outer peripheral surface of the steel pipe column main body located below the joint portion must be used. However, if a pair of keys is provided at such a position, the joint portion of the steel pipe column will protrude greatly upward from the holding device. Then, when the construction site is in a low-flying environment, the work space in the height direction becomes small, which may cause inconvenience in the work of joining the upper steel pipe columns.

Under such circumstances, as a method of supporting the lower steel pipe column by the holding device without providing a pair of keys, a method of providing a device capable of sandwiching the steel pipe column in the holding device is also adopted. However, if the vicinity of the upper end portion of the steel pipe column, that is, the height range in which the female threaded portion is formed on the inner peripheral surface is sandwiched, the female threaded portion is slightly deformed, and it takes time and effort to rotate the male threaded portion. Further, as the number of steel pipe columns to be added increases, the total weight also increases, so that the force for holding the steel pipe columns also increases. Then, since the amount of deformation of the female threaded portion also increases, it becomes difficult to rotate the male threaded portion as the construction progresses, which hinders the work itself of adding the steel pipe column.

The present invention has been made in view of the above problems, and a main object thereof is to improve workability when building a steel pipe column in an upright posture into an underground hole while adding it via a screw joint. be.

In order to achieve such an object, the holding mechanism of the steel column of the present invention is located on the lower side when a steel column in an upright position having screw joints at the upper end and the lower end is added by using the underground hole. A steel pipe column holding mechanism that holds the steel pipe column in a state of hanging in the underground hole, and a tapered surface is formed on the outer peripheral surface of the threaded joint provided at the lower end of the steel pipe column. The holding mechanism projects toward the openable support stand provided with an opening through which the steel pipe column can be inserted and the steel pipe column inserted through the opening, and the tapered surface of the screw joint is placed on the holding mechanism. It is characterized by comprising a plurality of support pieces having a mounting surface.

According to the holding mechanism of the steel pipe column of the present invention, a support piece is provided in the holding mechanism for holding the lower steel pipe column, and the mounting surface formed on the support piece has a taper formed in the female thread joint of the steel pipe column. Place the surface. As a result, no external force that deforms the female threaded joint, such as tightening the female threaded joint or welding and fixing a member for mounting on the support piece to the female threaded joint, does not act. Therefore, when joining the lower steel pipe column and the upper steel pipe column, it is possible to smoothly perform the screwing and tightening work of the screw joint.

Further, since the female screw joint at the upper end of the steel pipe column is placed on the support piece, the top end of the lower steel pipe column does not protrude significantly above the holding mechanism. This makes it possible to increase the height of the work space above the holding mechanism even when the construction site is in a low-flying environment.

According to the present invention, the steel tube column is held by the holding mechanism by mounting the tapered surface formed on the female thread joint at the upper end of the steel tube column on the support piece provided in the holding mechanism. Not only does the end not protrude significantly above the holding mechanism, but no external force that deforms the female threaded joint acts. Therefore, even when the construction site is in a low-flying environment, it is possible to improve workability when constructing a steel pipe column in an upright position in an underground hole while adding it via a screw joint.

It is a figure which shows the steel pipe column which comprises the threaded joint in embodiment of this invention. It is a figure which shows the outline of the holding mechanism and the joining device in a low-flying environment in embodiment of this invention. It is a figure which shows the base frame of the holding mechanism in embodiment of this invention. It is a figure which shows the open-and-open type support pedestal mounted on the base pedestal in embodiment of this invention. It is a figure which shows the support piece in embodiment of this invention. It is a figure which shows the other example of the support piece in embodiment of this invention. It is a figure which shows the state which supports the steel pipe column by the holding mechanism in embodiment of this invention. It is a figure which shows the detail of the rotation mechanism in embodiment of this invention. It is a figure which shows the rotational torque receiving metal fitting and the rotational torque receiving shear key in embodiment of this invention.

The present invention is a device used when adding a steel pipe column in an upright posture via a threaded joint by utilizing an underground hole, and is particularly suitable when the construction site is in a low head environment. .. The details of the holding mechanism of the steel pipe column will be described below with reference to FIGS. 1 to 9 together with the joining device provided with the holding mechanism.

In the present embodiment, a case where a structural pillar having a desired member length is constructed by sequentially adding steel pipe columns in an upright posture and the column is built in an underground hole is given as an example. First, a steel pipe column provided with a threaded joint will be described with reference to FIG.

≪Outline of steel pipe column≫
As shown in FIG. 1, the steel pipe column 1 includes a steel pipe column main body 2 and screw joints 3 provided at both ends thereof. The threaded joint 3 is composed of a female threaded joint 31 provided on the upper end side when the steel pipe column main body 2 is in an upright position and a male threaded joint 32 provided on the lower end side.

The female threaded joint 31 has a tubular body 31a arranged coaxially with the steel pipe column 1, a female threaded portion 31b formed on the inner peripheral surface of the tubular body 31a, and a downward tapered surface 31c formed on the outer peripheral surface. I have. The lower end side of the cylinder 31a fixed to the steel pipe column 1 has the same pipe diameter as the steel pipe column 1, and the upper end side including the height range in which the female screw portion 31b is provided is thickened to form a steel pipe. The pipe diameter is formed larger than that of the pillar 1. Therefore, on the outer peripheral surface of the tubular body 31a, a downward tapered surface 31c is formed at a portion where the pipe diameter changes.

On the other hand, the male threaded joint 32 includes a tubular body 32a arranged coaxially with the steel pipe column 1 and a male threaded portion 32b formed on the outer peripheral surface of the tubular body 32a. Therefore, when adding the steel pipe column 1 in the upright state, insert the male screw joint 32 provided in the upper steel pipe column 1b into the female threaded joint 31 provided in the lower steel pipe column 1a, and then insert the male threaded joint 32 in the upper steel pipe column 1b. The pillar 1b is rotated and the male screw portion 32b is tightened and joined to the female screw portion 31b.

Further, below the steel pipe column main body 2, a pair of torque introduction metal fittings 21 used for joining via these screw joints 3 are provided on the outer peripheral surface at intervals of 180 ° in the circumferential direction. Further, above the steel pipe column main body 2, a pair of rotational torque receiving shear keys 22 are provided on the outer peripheral surface at intervals of 180 ° in the circumferential direction. Further, the steel pipe column main body 2 is provided with an outer diaphragm 23 for the beam joint at a height position which becomes a joint portion with the beam when the underground structure is later constructed.

The rotational torque receiving shear key 22 functions as a rotation stopper for the lower steel pipe column 1a when the upper steel pipe column 1b is rotated with respect to the lower steel pipe column 1a and the two are joined by the screw joint 3. The rotational torque receiving shear key 22 will be described later together with the joining device 100 provided with the holding mechanism 200.

≪Steel pipe column joining device≫
When joining the steel pipe column 1 having the above configuration in an upright posture, the steel pipe column joining device 100 as shown in FIG. 2 is used. The joining device 100 is installed on the ground surface so as to surround the hole opening of the underground hole H, and includes a holding mechanism 200 and a rotation mechanism 300.

The holding mechanism 200 has a function of holding the steel pipe column 1 in an upright posture in a state of hanging in the underground hole H. Further, the rotation mechanism 300 has a function of rotating the steel pipe column 1 to be added to the steel pipe column 1 held by the holding mechanism 200 and hanging down.

≪≪Holding mechanism≫≫
The holding mechanism 200 includes a base pedestal 210 mounted on the foundation concrete B provided to protect the hole opening of the underground hole H, and an openable support pedestal 220 provided on the base pedestal 210. .. Further, as shown in FIGS. 3 and 4, the support piece 230, the guide member 240, the guide support column 250, and the rotational torque receiving metal fitting 260 are provided.

≪Base stand≫
As shown in FIG. 3, the base pedestal 210 is composed of a pair of halved pedestals 210a in which a flat plate-shaped member is halved. The pair of half-split pedestals 210a can be connected via a fastening member 212 such as a bolt, and when connected, an insertion hole 211 sufficiently larger than the cross section of the steel pipe column 1 is formed at substantially the center. That is, when the steel pipe column 1 is joined as shown in FIG. 1, the insertion hole 211 is formed to be at least larger than the beam joint outer diaphragm 23.

≪Openable support stand≫
As shown in FIG. 4A, the openable / closable support pedestal 220 is composed of a substantially flat plate-like member in which a pair of split support pedestals 220a are connected via a telescopic device 222 such as a hydraulic jack, and the outer shape thereof is a base pedestal. It is formed smaller than 210. Further, in the pair of split support pedestals 220a, the inner peripheral surfaces 221 facing each other are provided in a shape along the outer peripheral surface of the steel pipe column 1, and an opening is formed in a plan view.

As shown in FIGS. 4A and 4B, the opening formed by the inner peripheral surface 221 is formed by the pair of split support pedestals 220a approaching or separating (opening / closing) due to the expansion / contraction operation of the expansion / contraction device 222. It is configured to scale. The expansion and contraction of the opening formed by the inner peripheral surface 221 is performed above the insertion hole 211 of the base frame 210, the opening at the time of expansion is larger than the insertion hole 211, and the opening at the time of diameter reduction is from the insertion hole 211. It is configured to be smaller.

≪Support piece≫
As shown in FIG. 5, the inner peripheral surface 221 forming the above opening has a height corresponding to the member thickness of the openable support pedestal 220 in a direction parallel to the outer peripheral surface of the steel pipe column 1 when viewed from the side. A plurality of support pieces 230 are provided in this height range or in the vicinity of the upper and lower ends thereof.

As shown in FIGS. 4B and 5, the support piece 230 is provided with a pair of split supports on the back surface side so as to project toward the lower steel pipe column 1a inserted through the opening of the openable support frame 220. It is fixed to the gantry 220a. Further, on the front surface side, a mounting surface 231 on which the lower steel pipe column 1a is mounted is formed. The mounting surface 231 is formed on an upward inclined surface that can be in contact with the downward tapered surface 31c formed on the outer peripheral surface of the female threaded joint 31.

In FIG. 5, the case where the mounting surface 231 provided on the support piece 230 is arranged at an intermediate position within the height range of the inner peripheral surface 221 is taken as an example. However, the height position is not limited to this. For example, the support piece 230 may be provided so that the mounting surface 231 is arranged at the lowermost end of the inner peripheral surface 221 or at a position lower than that.

Then, the position of the top end of the lower steel pipe column 1a can be lowered, and a larger work space in the height direction above the holding mechanism 200 can be secured. In this way, the height position of the mounting surface 231 on the support piece 230 can be appropriately changed within the height range of the inner peripheral surface 221 forming the opening of the opening / closing type support frame 220, so that the work space can be changed in the height direction. It is possible to make adjustments to increase or decrease.

Further, as shown in FIG. 6, the support piece 230 may be fixed to the upper surface of each of the pair of split support pedestals 220a. Alternatively, a notch may be provided on the inner peripheral surface 221 and the support piece 230 may be fixed to the notch. In either case, the mounting surface 231 of the support piece 230 may be fixed so as to be arranged at a position protruding from the inner peripheral surface 221 of each of the pair of split support pedestals 220a toward the steel pipe column 1.

≪Guide member≫
As shown in FIGS. 4A and 4B, the guide member 240 is provided on the upper surface of the base pedestal 210 in a protruding shape so that the pair of split support pedestals 220a can be smoothly slid by the telescopic device 222. ..

In the present embodiment, four guide members 240 are provided for each of the pair of half-split pedestals 210a, and in each case, the pair of split support pedestals 220a extends in the sliding direction, and the pair of split support pedestals 220a It is provided so as to be in contact with each outer edge. As a result, the pair of split support pedestals 220a is guided by the guide member 240 in the moving direction due to the expansion / contraction operation of the expansion / contraction device 222, so that the pair of split support pedestals 220a can smoothly slide and move on the base pedestal 210.

≪Guide support≫
Further, the holding mechanism 200 is provided with a guide column 250 for guiding the slide movement of the pair of split support mounts 220a and stably supporting the load of the steel pipe column 1 acting on the pair of split support mounts 220a. As shown in FIG. 4B, the head expansion pin 251 and the elongated hole 252 are provided.

The head expansion pin 251 is erected at a predetermined position on the upper surface of the base frame 210 as shown in FIG. 3, and has a length such that the head expansion pin is located above the openable support frame 220 as shown in FIG. ing. Further, as shown in FIG. 4A, the elongated hole 243 is provided at a position corresponding to the head expansion pin 251 in the pair of split support mounts 220a, extends in the expansion / contraction direction of the expansion / contraction device 222, and the groove width thereof is wide. It is formed narrower than the head expansion of the head expansion pin 251.

As shown in FIG. 7, the set of the expansion pin 251 and the elongated hole 243 having the above configuration has the expansion head of each of the pair of split support pedestals 220a in a state where the shaft portion of the expansion pin 251 is inserted through the elongated hole 243. It is in contact with the upper surface. This is because when the steel pipe column 1 is held by the holding mechanism 200, the load of the steel pipe column 1 acts on the inner peripheral surface 221 of each of the pair of split support pedestals 220a to which the support piece 230 is fixed. Therefore, it is possible to suppress the behavior that the inner peripheral surface 221 side of the pair of split support pedestals 220a descends and the outer peripheral surface side tends to rise.

Therefore, as shown in FIG. 4B, the set of the expansion pin 251 and the elongated hole 243 is provided near the outer peripheral edge of each of the pair of split support pedestals 220a in the state where the opening of the openable support pedestal 220 is most reduced in diameter. It is arranged and supports the steel pipe column 1 more safely. In the present embodiment, since the pair of split support pedestals 220a are formed in a substantially rectangular shape in a plan view, a set of head expansion pins 251 and elongated holes 243 are arranged in the vicinity of the four corners, respectively. Further, the head expansion pin 251 may be detachably installed on the base frame 210, or the head expansion pin may be detachably attached to the shaft portion.

≪Connecting plate≫
Further, as shown in FIG. 4B, the connecting plate 253 is attached after the steel pipe column 1 is supported by the support piece 230 provided on the openable support stand 220, and is expanded and contracted as shown in FIG. It is made of a strip-shaped plate material extending in the expansion / contraction direction of the device 222. The connecting plates 253 having such a shape are arranged in pairs with an opening in between, and are detachably fixed via fastening members such as bolts, in such a manner that they are spread over a pair of split support pedestals 220a.

As a result, as shown in FIG. 7, in a state where the steel pipe column 1 is held by the holding mechanism 200, the pair of split support pedestals 220a are connected by the expansion / contraction device 222 and the connecting plate 253. Therefore, when the downward tapered surface 31c of the female threaded joint 31 abuts on the mounting surface 231 of the support piece 230, each of the pair of split support pedestals 220a slides and moves in the direction of expanding the diameter due to the load of the steel pipe column 1. It is possible to suppress the behavior of.

≪Rotating torque receiving bracket≫
Further, the openable / closable support pedestal 220 is provided with a rotary torque receiving metal fitting 260 into which the rotary torque receiving shear key 22 provided on the steel pipe column 1 described above is fitted.

As shown in FIG. 4A, the rotational torque receiving metal fitting 260 is provided in a recess provided on the inner peripheral surface 221 of each of the pair of split support pedestals 220a, and is formed in a U shape in a plan view. There is. The U-shaped opening portion 261 is arranged so as to face the direction facing the steel pipe column 1, and the rotational torque receiving shear key 22 provided on the lower steel pipe column 1a is fitted into the opening portion 261.

As a result, even when a rotational force around the axis acts on the lower steel pipe column 1a, it is possible to suppress the behavior of the lower steel pipe column 1a rotating. If the rotational torque receiving metal fitting 260 can be provided so that the opening faces the steel pipe column 1, any of the holding mechanisms 200 can be provided according to the height position of the rotational torque receiving shear key 22 provided on the steel pipe column 1. It may be fixed to the member of.

≪≪Rotation mechanism≫≫
As shown in FIG. 8A, the rotation mechanism 300 is provided on the upper surface of the above-mentioned base frame 210, and includes a pair of columns 301 and a torque introduction device 302 provided for each of the columns 301. ..

The columns 310 are the upper surfaces of the pair of half-split pedestals 210a constituting the base pedestal 210, and face each other with the steel pipe column 1 at a position where they do not interfere with the pair of split support pedestals 220a that slide and move. Is located in. The base end of the torque introduction device 302 is installed on the side surface of the column 301.

An expansion / contraction device such as a hydraulic jack is adopted in the torque introduction device 302, and the expansion / contraction direction thereof is the tangential direction of the steel pipe column 1 as shown in FIG. 8A, and the expansion / contraction direction provided in the holding mechanism 200 is provided. It is set in a direction orthogonal to the device 222. In this state, as shown in FIG. 8B, it is installed in the upper steel pipe column 1b with the male thread joint 32 inserted in the female thread joint 31 of the lower steel pipe column 1a supported by the holding mechanism 200. The torque introduction fitting 21 is gripped.

As a result, the torque introduction device 302 extends while the torque introduction metal fitting 21 is gripped by the torque introduction grip metal fitting 303, thereby applying a rotational force to the upper steel pipe column 1b and connecting the male screw joint 32 to the lower steel pipe. Both can be joined by tightening to the female screw joint 31 of the column 1a.

≪≪How to build steel pipe columns≫≫
An example of a procedure for constructing a steel pipe column 1 in an upright position in an underground hole H while adding it via a screw joint 3 by using the steel pipe column joining device 100 described above is shown below.

≪Assembly and installation of joining device≫
The joining device 100 is installed on the foundation concrete B so as to surround the underground hole H. The installation work of the joining device 100 can be carried out in any state before and after the steel pipe column 1 is suspended from the underground hole H via the suspension jig J by a lifting device L such as a crane.

In the installation work of the joining device 100, first, a pair of half-split pedestals 210a are brought to the site, and then the base pedestal 210 is assembled by fastening them on the foundation concrete B via the fastening member 212 as shown in FIG. .. At this time, it is preferable that the axis of the insertion hole 211 of the base frame 210 and the axis O of the underground hole H are coaxially aligned.

Next, as shown in FIG. 4A, a pair of split support pedestals 220a and a pair of telescopic devices 222 are brought into the field and assembled on the base pedestal 210 to form an openable support pedestal 220. Assembling the openable / closable support pedestal 220 may use the guide member 240 and the head expansion pin 251 provided on the base pedestal 210. That is, after the pair of split support pedestals 220a is placed along the guide member 240 and the expansion pin 251 is inserted through the elongated hole 252 provided in the pair of split support pedestals 220a, the pair of split support pedestals 220a is inserted into the pair of expansion / contraction devices. Connect at 222.

In this way, after assembling the holding mechanism 200, the pair of columns 301 and the pair of torque introducing devices 302 are carried to the site, and these are installed at predetermined positions on the base frame 210 to assemble the rotation mechanism 300.

In this way, both the holding mechanism 200 and the rotating mechanism 300 can individually carry the constituent members to the site and assemble them into the joining device 100, so that the loading / unloading work should be carried out with a small machine such as a forklift. Can be done. In addition, since it has a simple structure, it is easy to assemble and disassemble, and even when the construction work of the steel pipe column 1 is carried out for each of a plurality of underground holes H, the installation and removal work is speeded up. It is possible to improve workability.

≪Retention of lower steel pipe column 1a≫
As shown in FIG. 7, the holding mechanism 200 of the joining device 100 supports the lower steel pipe column 1a suspended in the underground hole H.

First, with respect to the lower steel pipe column 1a suspended from the underground hole H, as shown in FIG. 4A, the rotational torque receiving shear key 22 is at a position corresponding to the rotational torque receiving metal fitting 260 in a plan view. Adjust the position so that. Further, the female screw joint 31 is located above the open / close type support pedestal 220, and the outer diaphragm 23 for the beam joint is arranged below the open / close type support pedestal 220.

At this time, the opening / closing type support pedestal 220 separates the pair of split support pedestals 220a so that the opening surrounded by the inner peripheral surface 221 is larger than the insertion hole 211 of the base pedestal 210. Therefore, when the steel pipe column 1 is suspended from the underground hole H, the outer diaphragm 23 for the beam joint and the openable support frame 220 do not conflict with each other.

Next, as shown in FIG. 4B, the pair of split support pedestals 220a are slid and moved so that the opening surrounded by the inner peripheral surface 221 of the openable support pedestal 220 is reduced in diameter, and the support piece 230 is made of a steel pipe. It is brought into contact with the pillar 1. After or at the same time, the height of the suspended lower steel pipe column 1a is appropriately adjusted, and as shown in FIG. 5, the downward tapered surface 31c formed on the outer peripheral surface of the female threaded joint 31 is formed. Is in contact with the mounting surface 231 of the support piece 230.

In this way, the lower steel pipe column 1a is held by the holding mechanism 200 via the support piece 230, and the rotary torque receiving shear key 22 of the steel pipe column 1 is fitted into the rotary torque receiving metal fitting 260 as shown in FIG. By being combined, the movement in the rotation direction is suppressed.

≪Joining of upper steel pipe columns≫
When the lower steel pipe column 1a is held by the holding mechanism 200, as shown in FIG. 2, the upper steel pipe column 1b is lifted by the lifting device L using the suspension jig H, and the male screw joint 32 is formed. It is suspended until it is inserted into the female thread joint 31 of the lower steel pipe column 1a.

In this state, as shown in FIG. 8, the torque introduction grip fitting 303 of the torque introduction device 302 provided in the rotation mechanism 300 is attached to the torque introduction fitting 21 of the upper steel pipe column 1b, and then the torque introduction device 302 is extended. The upper steel pipe column 1b is rotated. As a result, the female threaded joint 31 of the lower steel pipe column 1a and the male threaded joint 32 of the upper steel pipe column 1b are screwed and tightened, and both are joined.

After the upper steel pipe pillar 1b is added to the lower steel pipe pillar 1a by the above procedure, as shown in FIG. 4A, a pair of split support pedestals constituting the open / close type support pedestal 220 of the holding mechanism 200. The 220a is slid to expand the diameter of the opening surrounded by the inner peripheral surface 221. As a result, the insertion hole 211 of the base pedestal 210 has a cross section larger than that of the beam joint outer diaphragm 23 without being partially blocked by the pair of split support pedestals 220a. Further, since the lower steel pipe column 1a is suspended by the lifting device L together with the upper steel pipe column 1b, the joined lower steel pipe column 1a and the upper steel pipe column 1b are placed on the upper side. It can be inserted into the underground hole H by the length of the steel pipe column 1b.

By the above-mentioned procedure, the work of supporting the added steel pipe column 1 by the holding mechanism 200 and the work of joining a new steel pipe column 1 are repeatedly carried out to construct a structural pillar having a desired member length. This is built in the underground hole. At this time, since the axial center of the added steel pipe column 1 is arranged at a position where the axial center O of the underground hole H coincides with the axial center O by the holding mechanism 200, the holding mechanism 200 is constructed by adding the steel pipe column 1. It also has a function to assist the construction work of the structural pillar.

As described above, when the holding mechanism 200 of the joining device 100 holds the lower steel pipe column 1a, the downward tapered surface 31c formed on the outer peripheral surface of the female threaded joint 31 is used, so that the female threaded joint 31 is deformed. There is no external force that causes the above. Therefore, when the upper steel pipe column 1b is joined to the lower steel pipe column 1a and added, the screw joint 3 can be smoothly screwed and tightened.

Further, since the female screw joint 31 at the upper end of the lower steel pipe column 1a is placed on the support piece 230, the top end of the lower steel pipe column 1a may greatly protrude upward from the holding mechanism 200. not. As a result, even when the construction site is in a low-flying environment, it is possible to increase the height of the work space above the holding mechanism 200.

Further, as shown in FIGS. 5 and 6, the height of the top of the lower steel pipe column 1a can be adjusted by appropriately changing the height position of the support piece 230 with respect to the openable support stand 220. As a result, as shown in FIG. 2, when the construction site is in a low head environment, the position supported by the holding mechanism 200 can be set to a low position as shown in FIG. 5, so that the upper steel pipe column 1b It is possible to contribute to the improvement of workability of the work of joining.

The steel pipe column holding mechanism 200 and the joining device 100 of the present invention are not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the present embodiment, two support pieces 230 are provided for each of the pair of split support pedestals 220a, but the number thereof is not limited. Any quantity may be used as long as the female screw joint 31 can be placed on the support piece 230 in a stable state.

Further, in the present embodiment, the rotation mechanism 300 is equipped with a torque introduction device 302 composed of a telescopic device such as a hydraulic jack, but the present invention is not necessarily limited to this, and for example, a holding mechanism for holding the upper steel pipe column 1b. An all-around rotation type equipment equipped with a rotation mechanism for rotating and rotating may be adopted.

1 Steel pipe pillar 1a Lower steel pipe pillar 1b Upper steel pipe pillar 2 Steel pipe pillar body 21 Torque introduction metal fittings 22 Rotational torque receiving shear key 23 External diaphragm for beam joint 3 Threaded joint 31 Female threaded joint 31a Cylinder 31b Female threaded portion 31c Downward tapered surface 32 Male threaded joint 32a Cylindrical body 32b Male threaded part 100 Joining device 200 Holding mechanism 210 Base mount 210a Half-split mount 211 Insertion hole 212 Fastening member 220 Open / close support mount 220a Split support mount 221 Inner peripheral surface 222 Telescopic device 230 Support piece 231 Mounting surface 240 Guide member 250 Guide strut 251 Head expansion pin 252 Long hole 253 Coupling plate 260 Rotating torque receiving bracket 261 Opening part 300 Rotating mechanism 301 Strut 302 Torque introduction device 303 Torque introduction grip fitting H Underground hole B Foundation concrete L Lifting device J Hanging jig

Claims (1)

When a steel pipe column in an upright posture having screw joints at the upper end and the lower end is added using the underground hole, the steel pipe column located on the lower side is held in a state of hanging in the underground hole. It is a holding mechanism for steel pipe columns.
A tapered surface is formed on the outer peripheral surface of the threaded joint provided at the lower end of the steel pipe column.
The holding mechanism is
An openable support pedestal provided with an opening through which the steel pipe column can be inserted,
A plurality of support pieces having a mounting surface that protrudes toward the steel pipe column inserted through the opening and on which the tapered surface of the threaded joint is mounted.
A steel pipe column holding mechanism characterized by being provided with.

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