JP2009285663A - Pipe with female screw, supporting structure of stand and method of forming pipe with female screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent lowering of the strength of a small tubular part in a pipe with a female screw which is provided with a large tubular part, a tapered tubular part and the small tubular part on which a female screw is formed. <P>SOLUTION: The small tubular part 4 and the tapered tubular part 3 are equally divided around the axial center Z into a plurality of connected divided pieces 5 consisting of arc-shaped divided pieces 5a to form the small tubular part 4 and tapered tubular divided pieces 5b to form the tapered tubular part 3. Adjacent connected divided pieces 5 are connected to each other with overhung pieces 6 which are formed by connecting the projected ends of two opposed projected pieces 6a which are projected from each side edge of adjacent side edge of the connected divided pieces 5 along a direction extended from the axial center Z toward radial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a large cylindrical portion having a large-diameter hole, a small cylindrical portion having a small-diameter hole in which a female screw is formed on the inner peripheral surface of the hole, and a tapered cylindrical portion having a tapered hole extending from the large-diameter hole to the small-diameter hole. Relates to a pipe with a female thread arranged on the same axis and connected to each other, a support structure for a gantry including the pipe with a female thread, and a method for forming the pipe with a female thread.

Conventionally, the internally threaded pipe 100 is used for a leg portion 102 of a waterproof pan 101 as shown in FIG. First, the female threaded pipe 100 is squeezed while extending the distal end portion of the round pipe and the intermediate portion connected to the distal end portion to form a small tubular portion 105 at the distal end portion and a tapered tubular portion 104 at the intermediate portion. Then, the large tubular portion 103 is formed on the remaining base portion, and then, the female screw 105a is formed on the small tubular portion 105 to complete (Patent Document 1).
JP-A-8-74305

  However, the pipe 100 with a female thread has its tip portion extended as a whole, and as shown in FIG. 13B, the tip side of the tapered tubular portion 104 and the thickness of the small tubular portion 105 are reduced. It was weak in strength.

  In order to solve the above-described problems, an object of the present invention is to provide a pipe with a female thread that secures strength, a support structure for a gantry including the pipe with a female thread, and a method for forming the pipe with a female thread.

In order to obtain a pipe with a female thread that secures strength, the means adopted by the present invention according to claim 1 includes a large cylindrical part having a large-diameter hole and a small-diameter hole having a small-diameter hole having a female thread on the inner peripheral surface of the hole. In a pipe with a female thread in which a cylindrical portion and a tapered cylindrical portion having a tapered hole extending from a large diameter hole to a small diameter hole are arranged on the same axis and connected to each other, the small cylindrical portion and the tapered cylindrical portion Is equally divided around the shaft core into a plurality of connected divided pieces comprising an arcuate divided piece forming a small tubular part and a tapered divided piece forming a tapered tubular part, and adjacent connected divided pieces are It is connected with a projecting piece formed by connecting projecting ends of two projecting pieces projecting from each adjacent side edge of the connecting divided pieces along a direction extending in the radial direction from the shaft core. It is a pipe with a female thread.
The female threaded pipe includes the length of the intersection line of the intersecting portion of the outer surface of the large cylindrical portion and the virtual cross section perpendicular to the axis, and arbitrary portions of the small cylindrical portion and the tapered cylindrical portion. And the length dimension of the crossing line of each part where the virtual cross section intersects is substantially equal.

  In order to obtain a support structure for a gantry comprising the female threaded pipe according to claim 1, the means adopted by the present invention as claimed in claim 2 is the support structure for a gantry framed by a square pipe. A leg is formed using a pipe with a pipe, a large cylindrical part of the leg is joined to a square pipe of a gantry, and a height adjusting bolt is screwed onto a female screw of the small cylindrical part of the leg. This is a support structure for the gantry.

  In order to obtain the female threaded pipe forming method according to claim 1, the means adopted by the present invention according to claim 3 is an inner mold and a pipe in which the tip end of one pipe material is arranged inside the pipe material. 2. A pipe forming method with a female thread according to claim 1, wherein the pipe with a female thread is formed by press molding with a plurality of outer molds arranged around the outer circumference of the material. A cylindrical press surface for forming the arc-shaped divided piece smaller than a circle is provided, and the outer die faces a concave arc-shaped press surface for forming the arc-shaped divided piece and a tip connected to a rear end arc side of the concave arc-shaped press surface. The taper press surface for forming the tapered split piece approaching the virtual extension surface obtained by virtually extending the concave arc-shaped press surface, and the radial direction extending from one side of each of the concave arc-shaped press surface and the taper press surface. One for protruding piece molding A side press surface, and the other side press surface for forming the protruding piece extending along the radial direction from each other side of the concave arc-shaped press surface and the tapered press surface, and an inner die is provided inside the pipe material. Place the outer mold around the outer circumference of the pipe material at an equal angle to disperse multiple outer molds, and press the outer surface of the pipe material with multiple outer molds that advance toward the inner mold Indented, the inner die cylindrical press surface and the outer die concave arc-shaped press surface sandwich the arc-shaped split piece forming area of the pipe material to form the arc-shaped split piece, and at the outer die taper press surface Pressing the tapered split piece forming area of the pipe material to form the tapered split piece, and further pressing the two protruding piece forming areas of the pipe material between the adjacent side press surfaces of the adjacent outer molds Press molding process A demolding step of retracting the plurality of advanced outer molds to their original positions and separating the inner mold, and forming a female screw on the inner peripheral surface of the small cylindrical portion formed by the plurality of arc-shaped divided pieces In this order, the female thread forming step is performed in this order.

  Since the pipe with a female thread according to the present invention according to claim 1 protrudes a protruding portion extending in the radial direction from each adjacent side edge of the connecting divided piece forming the small cylindrical portion and the tapered cylindrical portion, Strength can be ensured by increasing the bending rigidity of the portion including the small cylindrical portion and the tapered cylindrical portion.

  Since the support structure for the gantry according to the second aspect of the present invention is formed with the leg portion using the female threaded pipe according to the first aspect, the female screw is firmly screwed into the small cylindrical portion of the leg portion. Well, the gantry can be firmly supported.

  According to a third aspect of the present invention, there is provided a female threaded pipe forming method comprising: an inner die arranged on the inner side of a pipe material and a plurality of outer die arranged on the outer circumference of the pipe material. Because it is formed into an arc-shaped divided piece, a tapered divided piece, and an overhang part without greatly changing the thickness of the material near the tip in the bending process, the strength of the small cylindrical part that forms the female screw is reduced. In addition, it is possible to obtain a pipe with a female thread that secures strength by increasing the bending rigidity of the portion including the small tubular portion and the tapered tubular portion by forming the overhang portion.

  A pipe with an internal thread according to the present invention (hereinafter referred to as “the present pipe”), a method for forming the present pipe (hereinafter referred to as “the present pipe forming method”), and a support structure for a gantry provided with the present pipe ( Hereinafter, a beam structure provided with a pipe of the present invention will be described based on an embodiment shown in the drawings.

  1 to 3 show an embodiment of the pipe of the present invention. 1 and 2 show a mode in which a large cylindrical portion is formed in a square pipe shape. FIG. 1 (A) is a front view, and FIG. 1 (B) is an eye view in FIG. 1 (A). 1C is a cross-sectional view taken along the line of FIG. 1A, and FIG. 2 is a cross-sectional view taken along the line of FIG. 1B. is there. FIG. 3 shows a mode in which the large cylindrical portion is formed in a round pipe shape, FIG. 3 (A) is a front view, and FIG. 3 (B) is a cross section taken along the knee line in FIG. 3 (A). FIG. 3C is a cross-sectional view taken along the ho-ho line in FIG. 4 to 9 show an embodiment of the pipe forming method of the present invention. 4 and 5 show a preparation process in which the inner die is arranged inside the pipe material and the outer die is arranged outside, and FIG. 4 (A) is a plan view in which the plunger of the press machine is omitted. 4 (B) is a front view showing the inner die by breaking the pipe material, and FIG. 5 is a front view showing the outer shape of the pipe material by omitting the plunger and the outer die and partially cutting the pipe material. . FIG. 6 is a perspective view showing an outer die of a press used in the pipe forming method of the present invention. FIG. 7 shows the middle of the press molding process in which the pipe material is press-molded by the inner die and the outer die of the press machine, and FIG. 7 (A) is a plan view in which the plunger is omitted, and FIG. FIG. FIGS. 8A and 8B show an end state of the press molding process, where FIG. 8A is a plan view in which the plunger is omitted, and FIG. 8B is a front view in which a part of the outer die is sectioned. FIGS. 9A and 9B show a state in which the outer die is retracted to the original position in the middle of the demolding process. FIG. 9A is a plan view in which the plunger is omitted, and FIG. 9B is a front view. .

  As shown in FIGS. 1A and 2, the pipe 1 of the present invention includes a base 1a having a large cylindrical portion 2 having a large diameter hole, and a small cylinder having a small diameter hole in which a female screw 4a is formed on the inner peripheral surface of the hole. A tip portion 1c having a cylindrical portion 4 and an intermediate portion 1b having a tapered cylindrical portion 3 having a tapered hole extending from a large diameter hole to a small diameter hole, and a large cylindrical portion 2, a small cylindrical portion 4 and a tapered cylindrical shape. The part 3 is arranged on the same axis Z and connected.

  As shown in FIG. 1 (C), the pipe 1 of the present invention has a plurality of virtual radial planes S in which the small cylindrical portion 4 and the tapered cylindrical portion 3 extend radially from the axial center Z with an equal angular deviation. Around the axis Z, it is equally divided into a plurality of connected divided pieces 5, and adjacent connected divided pieces 5 are connected to each other along the direction of a virtual radiation plane S extending radially from the axis Z. The projecting ends of two projecting pieces 6a that project from adjacent side edges and are opposed to each other are connected by an overhang portion 6 that connects the projecting ends. The connecting divided piece 5 forms a small tubular portion 4 with a plurality of arc-shaped divided pieces 5a at the distal end portion 1c, and tapers at a plurality of tapered divided pieces 5b whose width dimension decreases toward the distal end at the intermediate portion 1b. A cylindrical portion 3 is formed.

  The pipe forming method of the present invention for forming the pipe 1 of the present invention includes a preparatory process in which a single pipe material 10 is arranged in a press machine 20 having an inner mold and an outer mold, a press molding process in which the arranged pipe material 10 is pressed, and a press. The pipe material 10 includes a demolding process for demolding from the inner mold 23 and the outer mold 24 of the press machine 20, and a female screw forming process for forming the female screw 4 a on the demolded pipe material 10. Below, the pipe raw material 10, the press machine 20, a preparation process, a press molding process, a demolding process, and an internal thread formation process are demonstrated in detail.

  The pipe material 10 is a metal pipe made of the same mild steel as the transverse shape of the large cylindrical portion 2 of the pipe 1 of the present invention in a transverse shape transverse to the axial center. Is used. In this example, the pipe material 10 is made by crossing a plated soft steel pipe such as galvanized with a predetermined dimension. However, the pipe material 10 is not limited to this, and an aluminum vip, a stainless pipe, or the like may be used.

  The press machine 20 includes a base portion 21, an inner die 23 erected from the upper surface of the base portion 21, and four plungers 22 that move forward and backward toward the inner die 23, and an outer die is provided at the output end of each plunger 22. 24 is attached, and the outer die 24 is arranged around the outer side of the inner die 23 at an equal angle of 90 degrees, and the four outer dies 24, 24... Are dispersed. The inner die 23 of the press machine 20 is connected to the outer side surface of the cylindrical press surface 23a for forming the arc-shaped divided piece 5a smaller than the inscribed circle of the pipe material 10 and the rear end arc side of the cylindrical press surface 23a. The taper press surface 23b for forming the tapering divided piece 5b that approaches the press machine core (the longitudinal axis of the inner mold 23 and coincides with the axis Z of the pipe 1 of the present invention being formed) as it approaches the leading end. And a base fitting surface 23c that fits snugly on the inner peripheral surface of the hole of the pipe material 10, and the outer shape is a shape in which the inner surface shape and unevenness of the pipe 1 of the present invention are reversed. Each of the outer dies 24 of the press machine 20 has a concave arc-shaped press on the inner surface thereof toward the front end connected to the concave arc-shaped press surface 24a for forming the arc-shaped divided piece 5a and the rear end arc side of the concave arc-shaped press surface 24a. A tapered press surface 24b for forming a tapered split piece 5b that approaches a virtual extended surface obtained by virtually extending the surface 24a, and a protruding piece 6a that extends along the virtual radiation plane S from each left side of the concave arc-shaped press surface 24a and the tapered press surface 24b. The left side press surface 24c for molding, the right side press surface 24 for projecting pieces extending along the virtual radial plane S from the right side of each of the concave arcuate press surface 24a and the taper press surface 24b, and the taper press surface 24b A base clamping surface 24e extending from the end side along the axis of the press machine is provided, and the inner side surface is divided into four equal parts with the outer side surface of the pipe 1 of the present invention being reversed and uneven.

  In the preparation step, the inner die 23 is disposed on the inner side of the pipe material 10 while the base fitting surface 23c of the inner die 23 of the press machine 20 is externally fitted on the inner peripheral surface of the hole of the pipe material 10, and the pipe material 10 The four outer dies 24 are arranged in a distributed manner by shifting them by equal angles around the outer circumference.

  In the press molding step, the four outer molds 24 are simultaneously advanced toward the axis of the inner mold 23, and the outer surfaces of the pipe material 10 are pressed and depressed by the four outer molds 24, 24,. Then, the arc-shaped divided piece of the pipe 1 of the present invention is formed by pressing the arc-shaped divided piece forming area 10a (see FIG. 5) of the pipe material 10 between the cylindrical press surface 23a of the inner mold 23 and the concave arc-shaped press surface 24a of the outer mold 24. 5a and press the taper split piece forming area 10b of the pipe material 10 with the taper press surface 24b of the outer die 24 (in this example, the taper press surface 24b of the outer die 24 and the taper press surface 23b of the inner die 23) To form the tapered divided piece 5b of the pipe 1 according to the present invention, and further, between the adjacent side press surfaces 24c and 24d of the adjacent outer molds 24 and 24. Two projecting pieces forming area 10c of material 10, 10d are formed into overhanging portion 6 of the clamping pressure with the present invention a pipe 1 a.

  In the pipe 1 of the present invention, which is formed by press-molding the pipe material 10 by this press molding process, the projecting portion 6 has four distal end side projecting pieces 8 having a rectangular shape at the distal end portion 1c than the small tubular portion 4. Four intermediate projecting pieces 7 that project outwardly and become wider toward the tip in the intermediate portion 1b project outward than the tapered cylindrical portion 3, and the outer surface of the large cylindrical portion 2 and the axis Z The length dimension of the intersection line of the intersecting portion with the virtual transverse plane orthogonal to the cross section of the intersecting line with the virtual transverse plane orthogonal to the axial center Z at any location of the small tubular portion 4 and the tapered tubular portion 3 The lengths of the intersecting lines are substantially equal (“substantially equal” means that the adjacent arc-shaped divided piece forming area 10a, the tapered divided piece forming area 10b, and the protruding piece forming areas 10c and 10d in the pipe material 10 are mutually connected. Only the boundary of Runode, correspondingly, the length of the intersection line is because of the slightly different.) Is shaped to.

  In the demolding step, the four outer molds 24 moved forward are retracted to the original standby position to separate the pipe material 10 and the outer mold 24, and then the pipe material 10 is lifted upward, The inner mold 23 is separated.

  In the final female thread forming step, the pipe material 10 separated from the outer mold 24 and the inner mold 23 is subjected to female taping or the like on the inner peripheral surface of the small cylindrical portion 4 formed by the plurality of arc-shaped divided pieces 5a. A screw is formed to complete the pipe 1 of the present invention.

  In the present example, the pipe 1 of the present invention uses a square pipe as the pipe material 10, and forms the large cylindrical portion 2 into a square pipe shape as shown in FIG. The small cylindrical portion 3 and the tapered cylindrical portion 4 are equally divided into four continuous divided pieces 5 at four virtual radiation planes S that extend to pass through the outer corners 2a of the large cylindrical portion 2, A round pipe is used as the pipe material 10, and the large cylindrical portion 2 is formed in a round pipe shape as shown in FIG. 3C, and a plurality (four in the illustrated case) extending in the radial direction from the axis Z. The small cylindrical portion 3 and the tapered cylindrical portion 4 may be equally divided (in the case of illustration, four equal divisions) on the virtual radiation plane S.

  The pipe 1 according to the present invention is obtained by using the pipe forming method according to the present invention. Most of the tip portion 1c and the intermediate portion 1b (the adjacent arc-shaped divided piece forming area 10a, the tapered divided piece forming area 10b, the protruding piece forming area 10c in the pipe material 10 , The portion excluding the boundary of 10d) can be formed without extending, so that the thickness of the small cylindrical portion 4 of the tip portion 1c, the thickness of the tapered cylindrical portion 3 of the intermediate portion 1b, and the large cylindrical shape of the base portion 1a. The thickness dimension of the part 2 can be made to be the same as or approximate to each other, whereby the strengths of the small cylindrical part 4 and the tapered cylindrical part 3 forming the female screw 4a are not lowered.

  The pipe forming method of the present invention is to fold the boundary between adjacent arc-shaped divided piece forming area 10a, tapered divided piece forming area 10b, projecting piece forming areas 10c, 10d of pipe material 10, No force is applied, and the boundary part to be bent is not subjected to a large force as compared with the conventional stretching, so that the plating is not peeled even if the pipe material 10 is subjected to plating. Therefore, the pipe forming method of the present invention can form the pipe of the present invention 1 plated using the pipe material 10 plated in advance without performing an intermediate plating step.

  In the pipe forming method of the present invention, when the pipe material 10 having a square pipe shape is pressed, an intermediate portion 10-1 (see FIG. 5) of each side plate that is easily bent and deformed so as to be close to the shaft core is largely brought close to the shaft core. Since the outer corner portion 10-2 that is hardly bent and deformed so as to approach the shaft core is bent and deformed so as not to approach the shaft core, press molding is easy.

  In the pipe 1 of the present invention, as shown in FIG. 1, the projecting portion 6 projects outward from the small tubular portion 4 at the distal end portion 1c, and projects outward from the tapered tubular portion 3 at the intermediate portion 1b. Thus, the bending rigidity of the tip portion 1c and the intermediate portion 1b can be increased.

  10 and 11 show an embodiment of the gantry support structure of the present invention. FIG. 10 is a front view of the legs of the gantry support structure of the present invention, and FIG. 11 (A) and FIG. It is the perspective view which isolate | separated the mount frame and the leg part, Comprising: Each aspect which a mount frame and a leg part join is shown.

  The gantry support structure 30 of the present invention supports a waterproof pan (not shown) for bathroom construction and the like, and as shown in FIG. 11, a gantry 31 framed by square pipes 32, 32, and legs joined to the gantry 31. 33. As shown in FIG. 10, the leg portion 33 is formed by using the pipe 1 of the present invention, and a height adjusting bolt 35 is screwed to the female screw 4a of the small tubular portion 4 so that the height can be adjusted. As shown in FIG. 11, a square tubular large cylindrical portion 2 is joined to a square pipe 32 of a gantry 31.

As an aspect which joins the square cylindrical large cylindrical part 2 to the square pipe 32 of the said mount 31, there exists the aspect shown to the following (1)-(4).
(1) As shown in FIG. 11A, a square pipe 37 having a slightly small height is joined to the square pipe 32 of the gantry 31 by welding or the like, and a top plate 38 is joined to the upper side of the small square pipe 37 by welding or the like. A mode in which a rectangular concave portion having the same shape as or slightly larger than the outer shape of the large cylindrical portion 2 is formed on the inner corner side of the gantry 31 and the upper end side of the large cylindrical portion 2 is internally fitted and joined to the rectangular concave portion.
(2) As shown in FIG. 11B, a rectangular convex portion 39 having the same shape as the inner shape of the large cylindrical portion 2 or a slightly smaller outer shape is provided on the lower side of the square pipe 32 of the gantry 31. A mode in which the upper end side of the large cylindrical portion 2 is externally fitted and joined.
(3) Although not shown in the drawings, a mode in which the square end of the large cylindrical portion 2 is joined to the bottom surface of the square pipe 32 of the gantry 31 by welding or the like.
(4) Although not shown in the drawings, a mode in which the side surface of the square cylindrical large cylindrical portion 2 is joined to the side surface of the square pipe 32 of the gantry 31 by welding or the like.
These aspects (1) to (4) of the gantry support structure 30 of the present invention are easier to join than the aspect in which the round pipe-shaped legs are joined to the square pipe 32 of the gantry 31.

  In the frame support structure 30 of the present invention, the rectangular pipe 32 of the frame 31 and the large cylindrical portion 2 of the leg 33 are formed in the same shape, and the both types 32 and 33 can be formed with the same kind of pipe material 10, so The number of types of pipes required to process the structure 30 can be reduced. In the gantry support structure 30 of the present invention, a lock nut 36 is screwed to a height adjusting bolt 35 in advance and the height adjusting bolt 35 is screwed to the small cylindrical portion 4. Tighten to the lower end side of the tubular portion 4 so that the height adjusting bolt 35 is not loosened, and the lower end of the small tubular portion 4 is supported by the lock nut 36, so that the female screw 6a of the small tubular portion 4 is secured. The load concerning is reduced.

  FIG. 12 shows an embodiment of a beam structure provided with the pipe of the present invention, and is a plan view with the middle omitted. The beam structure 40 includes a frame 41 that supports a waterproof pan (not shown) and the like and is framed by square pipes 42, 42... And a beam portion 43 that is bridged between the square pipes 42 of the frame 41. The beam portion 43 is formed by using the pipe 1 of the present invention in which the middle portion thereof is a square pipe-like large tubular portion 2 and the tapered tubular portion 3 and the small tubular portion 4 are formed on both ends. Between the square pipes 42 and 42 to be inserted into the screw insertion holes 42a-1 and 42b-1 formed in the outer and inner side plates 42a and 42b of the square pipe 42, and the female screw 4a of the small tubular portion 4 Both ends are joined via mounting bolts 44, 44 screwed to each other. The beam structure 40 can bridge the beam portion 43 without welding between the square pipes 42 and 42 facing the gantry 41. In the beam structure 40, the rectangular pipe 42 of the gantry 41 and the large cylindrical portion 2 of the beam portion 43 have the same shape, and the both types 42 and 43 can be formed of the same kind of pipe material 10, so that the beam structure 40 is processed. It is possible to reduce the number of types of pipes required.

FIG. 1 shows an embodiment of the pipe of the present invention, and shows a mode in which a large cylindrical portion is formed in a square pipe shape. FIG. (A) is a front view and FIG. (B) is a diagram in FIG. A cross-sectional view taken along the line II, and FIG. 5C is a cross-sectional view taken along the roll line in FIG. FIG. 2 is a cross-sectional view taken along the line ha-ha in FIG. In the same embodiment, a mode in which a large cylindrical portion is formed in a round pipe shape is shown. FIG. (A) is a front view, and FIG. (B) is a cross section taken along a knee line in FIG. The figure and FIG. (C) are sectional views taken along the ho-ho line in FIG. 1 shows an embodiment of a pipe forming method of the present invention, and shows a preparatory step in which an inner die is arranged inside a pipe material and an outer die is arranged outside, and FIG. The top view and figure (B) which carried out the longitudinal section of the pipe raw material were the front views which showed the inner side type | mold. The preparatory process in the embodiment is shown, Comprising: It is the front view which fractured | ruptured a part of pipe raw material while omitting a plunger and an outer side type | mold. It is the perspective view which showed the outer side mold | type used for this invention pipe forming method. In the same embodiment, an intermediate mold and an outer mold are shown in the middle of a press molding process in which a pipe material is press molded. FIG. (A) is a plan view in which a plunger is omitted, and FIG. FIG. In the same embodiment, the end state of the press molding process is shown. FIG. (A) is a plan view in which the plunger is omitted, and FIG. (B) is a front view in which a part of the outer die is sectioned. In the same embodiment, it shows a state in which the outer die is retracted to the original position in the middle of the demolding step, FIG. (A) is a plan view with the plunger omitted, and FIG. (B) is a front view. It is. 1 is a front view of a leg portion showing an embodiment of the gantry support structure of the present invention. The embodiment is shown, and FIG. (A) and FIG. (B) are perspective views in which the gantry and the leg are separated, and show each mode in which the gantry and the leg are joined. 1 is a plan view showing an embodiment of a beam structure of the present invention, with an intermediate portion omitted. A conventional female threaded pipe is shown. FIG. (A) is a side view in which a conventional female threaded pipe is provided in a waterproof pan, and FIG. (B) is a perspective view of a conventional female threaded pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pipe with an internal thread (pipe of this invention) 2 ... Large cylindrical part 3 ... Tapered cylindrical part 4 ... Small cylindrical part 4a ... Female screw 5 ... Connection division | segmentation piece 6a ... Projection piece 6 ... Overhang | projection part 5a ... Arc-shaped division | segmentation Piece 5b ... Tapered divided piece 10 ... Pipe material 23 ... Inner die 24 ... Outer die 30 ... Mounting support structure (support structure of the present invention) 31 ... Mounting frame 32 ... Square pipe 33 ... Leg portion 35 ... Height adjustment bolt

Claims (3)

  The large cylindrical portion having a large diameter hole, the small cylindrical portion having a small diameter hole having a female screw formed on the inner peripheral surface of the hole, and the tapered cylindrical portion having a tapered hole extending from the large diameter hole to the small diameter hole are the same. In the internally threaded pipe disposed on and connected to the shaft core, the small tubular portion and the tapered tubular portion are composed of an arc-shaped divided piece that forms the small tubular portion and a tapered divided piece that forms the tapered tubular portion. A plurality of connected divided pieces are equally divided around the shaft core, and the adjacent connected divided pieces project from adjacent side edges of the connected divided pieces along a direction extending in the radial direction from the shaft core. A female threaded pipe characterized in that it is connected by an overhang part formed by connecting protruding ends of two opposing protruding pieces.   In a support structure for a frame framed by a square pipe, a leg portion is formed using the female threaded pipe according to claim 1, a large cylindrical portion of the leg portion is joined to the square pipe of the frame, and a small cylindrical shape of the leg portion is formed. A support structure for a gantry in which a height adjusting bolt is screwed onto a female screw of the section. 2. A female for forming a pipe with a female thread according to claim 1, wherein the tip of one pipe material is press-molded with an inner mold arranged inside the pipe material and a plurality of outer molds arranged around the pipe material. A threaded pipe forming method,
The inner mold is provided with a cylindrical press surface for forming the arc-shaped divided piece smaller than the inscribed circle of the pipe material on the outer surface,
The outer die is a concave arc-shaped press surface for forming the arc-shaped split piece, and the tapered division approaching a virtual extension surface obtained by virtually extending the concave arc-shaped press surface toward the front end connected to the rear end arc side of the concave arc-shaped press surface. Tapered press surface for piece forming, one side press surface for projecting piece extending from one side of each of concave arc-shaped press surface and tapered press surface in the radial direction, concave arc-shaped press surface and taper The other side press surface for forming the protruding piece extending from the other side of the press surface along the radial direction,
A preparatory step of disposing a plurality of outer molds by arranging an inner mold inside the pipe material and arranging an outer mold at equal angles around the pipe material;
The outer surface of the pipe material is pressed and recessed by a plurality of outer molds that are advanced toward the inner mold, and the arc-shaped split pieces of the pipe material are formed by the cylindrical press surface of the inner mold and the concave arc-shaped press surface of the outer mold. The area is clamped and formed into the arc-shaped divided piece, and the tapered material is formed into the tapered divided piece by pressing the tapered divided piece forming area of the pipe material with the taper press surface of the outer mold, and the adjacent outer mold is adjacent. A press-molding process in which two projecting piece forming areas of the pipe material are sandwiched between the side press surfaces and molded into the overhang portion;
A demolding step of retracting the plurality of advanced outer molds to their original positions and separating the inner mold, and forming a female screw on the inner peripheral surface of the hole of the small cylindrical portion formed by the plurality of arc-shaped divided pieces The female thread forming step is performed in this order.

Images