JPH07197917A - Bolt connection structure - Google Patents

Abstract

PURPOSE:To dispense with welding work of a bolt so as secure safeness and enhance workability by engaging a connection cylinder of a predetermined length with a plurality of bolts where ridges are arranged in parallel and engaged by a preset length. CONSTITUTION:Two screw bolts 1, 2 having ridges 11, 21 of the same shape are engaged with each other by a predetermined length while maintaining the parallel state thereof. Meanwhile, semi-cylindrical surfaces having a dimension, capable of inscribing with the outer peripheral surfaces of the bolts 1, 2 are formed at the right and left ends of the inner circumferential surfaces 31 of a connection cylinder 3 constituted of a carbon steel pipe. The connection cylinder of a predetermined length is previously fitted to the upper bolt 1 fixed at the upper end thereof to the support structure, and is driven, by a hammer, in the axial direction up to a position surrounding the outer peripheral surface in a portion engaged with the ridges 11, 21 of the bolts 1, 2. Consequently, the inner circumferences 31 of the connection cylinder 3 are tightened and engaged with respect to the outer peripheral surfaces of the bolts 1, 2 engaged with the ridges 11, 21, and accordingly, is sufficiently resistant against tensile strength of, e.g., rod steel to be used as a suspension bolt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of bolts having a smaller load than a sectional area, such as a hanging bolt used for attaching a ceiling base material or a pipe or a steel bar used for hanging a steel bar of a duct. The present invention relates to an improved connection structure for directional connection.

[0002]

2. Description of the Related Art A long threaded bolt having threads or a threaded bolt having the same diameter with threads on both ends of a cylinder is connected in the same direction over the entire length of the cylinder, and usually has a cross section of 6 mm.
Rectangular long high nuts or turnbuckles are used. In addition, align the lower end of the hanging bolt that is hung from the attic or a supporting member such as a beam with the upper end of the lower hanging bolt that is arranged parallel to this bolt, and set the threads of both bolts to a prescribed length relative to each other. There is also a case where a butt joint is formed by fitting them together, and a connecting method is used in which H-shaped grooves formed between both bolts are welded from both sides.

Also, in Japanese Utility Model Application Laid-Open No. 50-7325, there is disclosed a "substantially oval cover which is reasonably larger than the occupied cross section when two reinforcing bars to be connected are contacted in a parallel axis relationship. In the intermediate space between the target inner side surface in the major axis direction of the covering cylinder and the respective rebar surfaces respectively facing these inner side surfaces under the condition that the required connecting portions of both the above-mentioned rebars are lined up and penetrated. On the other hand, a connection structure in which each of the different sloped restraining pieces having a curved cross-section corresponding thereto is forcibly driven and stabilized from the opposite end of the cover cylinder.
As described in Japanese Utility Model Publication No. 57-7686, "Connected parts of reinforcing bars to be connected are overlapped with each other, and an elliptical sleeve is fitted and fitted into the overlapped parts, and press fit is applied to both opposite walls of the sleeve. Reinforcing bar joint structure formed by penetrating a wedge having a substantially rectangular cross-section perpendicular to the direction to press the wedge between the rebars and crimp the rebar and the sleeve together " As disclosed in FIG. 1 and FIG. 3 of Public Technical Report No. 92-122, “A combination of a metal sleeve having an inner diameter slightly smaller than the outer diameter of the reinforcing bar 1 is a C type combination. A joint jig 4 for a parallel lap joint that is attached to a reinforcing bar by utilizing elasticity is also known.

[0004]

It is disadvantageous to use a specially shaped high nut to connect a male thread, such as a lightly loaded suspension bolt that uses multiple long threaded bolts or double threaded bolts. , In normal construction work,
The connection method for welding the butt joints of bolts and bolts described in [0002] is used, but the upper part of the suspension bolt is welded to the embedded insert in the case of reinforced concrete and welded in the case of steel frame. It is attached by an appropriate construction method such as. In order to weld the upper end of the lower suspension bolt to the lower end of the suspended suspension bolt in this manner, not only is the support of the work piece unstable, but the welding also takes a vertical posture. Moreover, since the connection of the suspension bolt is a work at a high place, a considerable skill is required for this kind of welding work. In addition, welding work generates gas and fumes, and the working environment is bad, and there is a risk of fire.

In addition, in the connection structure using the oval sleeve described in the item [0003], it is not possible to achieve sufficient mechanical strength unless the restraining piece or the wedge with a slope is driven. Further, since the C-shaped metal sleeve having an inner diameter slightly smaller than the outer diameter of the reinforcing bar clamps the reinforcing bar by its elasticity, it can be used as a means for splicing the reinforcing bars arranged in the horizontal direction in parallel. It may not, but it is not suitable for male screw connection structures such as hanging bolts that are loaded vertically.

[0006] The invention of Japanese application was invented in order to solve the technical problems of the connection construction method of [0004] and the connection structure using the sleeve described in the preceding paragraph. The purpose is to obtain a bolt connection structure that is good, safe, and free from the risk of fire and that anyone can easily handle.

[0007]

According to the present invention, in a bolt connecting structure, a single bolt having parallel threads at a rear end portion thereof having a substantially equal effective diameter, a helix angle of a helical winding, and a mountain shape of a screw thread, A plurality of bolts arranged parallel to each other and threaded with each other for a predetermined length, including other bolts having the parallel threads at the tips along the bolts, and the screws of these bolts. A semi-cylindrical surface portion that surrounds the portion where the ridges are fitted and is inscribed in the outer peripheral surface of each bolt, and a flat surface portion that follows these semi-cylindrical surface portions and that opposes the portion is oval, It is characterized by comprising a connecting cylinder having a thickness and an axial length close to the above portion.

Further, the bolt connecting structure may have an inner peripheral surface provided with a connection between the bolts, which is dimensioned to be a tight fit with the outer peripheral surface of each bolt. A nut that engages with the lower end of the connecting tube, which is fitted to the bolt, may be provided.

Further, in the bolt connection structure, the inner peripheral surface of the connecting cylinder or the inner periphery of the connecting cylinder whose size is a tight fit with the outer peripheral surface of each bolt in which the screw thread is fitted has the screw thread fitted therein. Also, a lid having one hole through which the bolt penetrates may be provided at the end portion of the connecting cylinder having a size that is an intermediate fit or a clearance fit with respect to the outer peripheral surface of each bolt.

Further, in the bolt connecting structure of the present invention, the axial length of the engaged portion of the screw thread is increased, and the front and rear end portions of both parallel screws arranged so as to sandwich the portion of each bolt. And [0008] or [0]
[009] item may be covered with the connection tube.

Further, the bolt connection structure of the present invention is such that the axial length of the engaged portion of the screw thread is increased and the continuous length is close to the engaged portion of the screw thread of each bolt. [0008] or [00]
[09] may be covered with the connection cylinder.

In addition, the bolt connecting structure of the present invention is such that the rear end portion of one bolt is provided with a tip portion of a short bolt along the rear end portion.
At the rear end of this short bolt, another bolt along the above-mentioned short bolt is placed on the same axis as the above-mentioned one bolt, and the threads are fitted by a predetermined length. Continuing [0008]-[00]
It is more preferable to use the bolt connection structure described in the paragraph [0007], wherein the bolts are integrally restrained by the connection cylinder according to any one of the paragraphs [09].

[0013]

According to the invention of the present application, as described in the paragraph [0007], the rear end of one bolt and the tip of the other bolt along the bolt are screwed together by a predetermined length. A plurality of bolts that are equipped with parallel threads with an effective diameter, the helix angle of the spiral winding, and the thread ridges that are almost equal, and are arranged in parallel with each other, and the half that inscribes these bolts and inscribes the outer peripheral surface of each bolt. Since the cross-section consisting of the cylindrical surface portion and the flat surface portion facing each other sandwiching the fitted portion of the screw thread following them is an ellipse and is composed of a connecting tube having a predetermined thickness and an axial length larger than the portion. When a tensile force is applied to the tip of one bolt and the rear of the last of the plurality of bolts, each bolt and connecting tube are integrated in the threaded portion. Become the tensile force It will be responsible. In other words, the stress generated by being dispersed inside the material forming this portion balances against the tensile force against the tensile force.
Although the effective cross-sectional area of the fitted part is extremely small and each bolt with a relatively short length of the fitted part and the connection tube are combined, it is not possible to obtain a pulling force similar to a hanging bolt or a steel bar used for hanging a steel bar. Can withstand enough.

Further, as described in the section [0008],
If you use a connecting tube with a size that fits tightly on the outer peripheral surface of each bolt, the connecting tube will slide downward even when it is used as a connecting structure for bolts that can be hung vertically like a hanging bolt. Or do not worry about falling out. Also,
Even if the thread of the bolt is a triangular screw or a trapezoidal screw, and if a tensile force is applied to the tip of the upper bolt and the rear end of the lower bolt among the multiple bolts, the flanks of both bolts The slippage of the two bolts opens the gap between the two bolts, and the height of the screw catch is small. Also,
The connection cylinder is held in a fixed position in the case where a nut is fitted to at least one of the bolts (lower bolts) and engages with the end portion (lower end) of the connection cylinder.

Further, if a lid having one hole through which the bolt penetrates is provided at the end of the connecting tube, the upper end is used when used as a connecting structure of bolts which can be hung vertically like a hanging bolt. Hold the bolt on the fixed upper bolt through the hole of the connecting cylinder, and fit the thread of the tip of the lower bolt to the rear end of the bolt for a specified length. By covering the outer periphery of the fitted portion of the mountain with the connecting cylinder from the top until the lower surface of the lid comes into contact with the top of the lower bolt, the connecting cylinder is fitted to the upper bolt and kept in place. Since the lower surface of the lid is supported by the top of the lower bolt, the connecting cylinder does not slide downward or fall out.

Further, at the end portion of the connecting cylinder, the inner circumference of which is an intermediate fit or a clearance fit with a small fitting section with respect to the outer circumferential surface of each bolt fitted with a screw thread,
If you place a lid with one hole through which the bolt penetrates,
The fitting of the connecting tube becomes easy.

In the bolt connection structure of the present invention, [0008] or [0009] is provided at the front end and the rear end of both parallel screws sandwiching the portion of each bolt in which the engaged portion of the thread is elongated. ] By fitting the connecting cylinder of section above, the fitting length of both screws can be set freely, and the tensile force applied to the tips of both bolts is the same as the fitted part of a relatively long thread, Since it will be dispersed and supported by the two connecting tubes, the bolt connection structure is
It can withstand higher tensile forces than those described in [0013] to [0016].

Also, a continuous connecting cylinder of [0008] or [0009] having a length in the fitted portion of the thread and an axial length close to the fitted portion of the thread of each bolt is covered. With the bolt connection structure, the tensile force is dispersedly supported by the fitted portion of the relatively long screw thread and the long connecting tube, and [00
It is possible to bear a tensile force larger than that described in the items [13] to [0016].

As a further different form of the bolt connecting structure of the present invention, a short bolt tip along the rear end of one bolt is provided on the same axis as one bolt at the rear end of the short bolt. The other bolts along the bolt are arranged so that the threads are fitted to each other for a predetermined length, and they are inscribed continuously on the outer peripheral surface of each bolt [0008]
Assuming that these bolts are integrally restrained by the connecting cylinder of the item [0009] or the item [0009], a tensile force is applied to the tip of the upper bolt and the rear end of the lower bolt of the plurality of bolts. Also, when the bolts are added, since the axial centers of both bolts coincide with each other, no bending moment is applied to each bolt.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 10 are explanatory views showing each embodiment of the present invention.

(Embodiment 1) In the bolt connecting structure illustrated in FIGS. 1 to 3, the upper bolt 1 is JISB 10
Mechanical properties of 51-991 steel bolts and machine screws 3.
Table 4 of the section and shows the part with the lower thread in the double screw bolt made by rolling the wire rod corresponding to the carbon steel of strength category 3.6 specified in the heat treatment, JIS B
0206-1973 Unified Coarse Thread 3 / 8-16U
The NC-A screw thread 11 is provided, and the upper end (not shown) is attached to the support structure. 2 is thread 2
The upper end 22 of the lower bolt 2 has a length of 1 = 20
The thread 21 of the lower bolt 2 is fitted to the thread 11 of the bolt 1 along the lower end 12 of the bolt 1 by mm. The bolts 1 and 2 in this example are parallel threads having the same total effective diameter, and the thread 11 of the upper bolt 1
Since the screw thread 21 of the lower bolt 2 has the same helix angle of the spiral winding and the thread shapes of the screw threads 11 and 21 are the same, as shown in the enlarged view of FIG.
2, the threads 11 and 21 are engaged with each other while maintaining the parallel state.

Reference numeral 3 denotes a connecting cylinder manufactured from a carbon steel pipe for machine structure according to JIS G 3445-1998, in which the left and right ends of the inner peripheral surface 31 are connected to the outer peripheral surfaces 14 of the bolts 1 and 2.
The semi-cylindrical surfaces 32, 32 of the size inscribed in 24 have the following parts as parallel flat surfaces 33, 33, the major axis of which is the screw threads 11, 21 of the two bolts 1, 2 described above. As described above, the bolts 1 and 2 sandwiching the mutually engaged portions C are formed into an oval shape having a size slightly smaller than the maximum cross-sectional length of the bolts 1, the cross-sectional thickness t = 1.6 mm, and the axial length h = 2.
It is made to 0 mm. Such a connecting cylinder 3 is placed by passing the upper end of the upper bolt 1 attached to the support structure in advance, and as shown in FIGS. 1 to 3, the threads 11 and 21 of the bolts 1 and 2 are fitted to each other. It is struck in the axial direction by a hammer to a position surrounding the outer peripheral surfaces 14 and 24 of the closed portion C. That is, in this embodiment, the inner circumference 31 of the connecting tube 3 is
However, the bolts 1 and 2 fitted with the threads 11 and 21
The outer peripheral surfaces 14 and 24 are tightly fitted.

In order to examine the tensile strength and the usage limit of the bolt connection structure thus assembled, FIGS.
An upper portion of the bolt 1 in the bolt connection structure illustrated in FIG.
The lower part of the bolt 2 is 500,000 at intervals of 300 mm.
The tensile test was performed by tightening the chuck on the N universal testing machine. In this test, tensile load 3079-3903N
A considerable amount of strain was generated between (314 kgf and 398 kgf), but beyond that, the load and strain were again proportional, and after that, the bolt connection structure began to yield, and the strain increased with a nearly constant load. The load and strain increased smoothly and fractured at 10493N (1070 kgf).
This is because the axial center of the upper bolt 1 and the lower bolt 2 are deviated to the left and right at the portion of the connecting cylinder 3, so that in the test in which the chuck interval of the tester is short as described above, the tensile load is 3079.
This is because the bolts 1 and 2 began to bend at N, and the breakage of the bolt connection structure was slightly caused by elastic deformation of the connecting cylinder 3 when a vertical load was applied to the upper portion of the bolt 1 and the lower portion of the bolt 2. It has been found that the flared threads 11 and 21 occur at the mating part C due to the bending of the chevron tip.

However, the short suspension bolts as described in the preceding paragraph are not used, and the suspension bolts used for attachments to ceiling base materials, pipe supports, etc. or suspension bolts such as steel bars used to suspend steel bars in ducts are used. Since a large load is not applied so that the bolts 1 and 2 bend, there is almost no problem. Further, the bolts 1 and 2 are JIS A65
Approximately 900 × 900 mm spacing, which is similar to a suspension bolt specified as a ceiling base material attachment in the architectural steel base material of 17-1989, and described as a strength test of the ceiling base material in the standard. In a downward loading test of a field rim receiver supported by a suspension bolt made of four rolling screws with a screw thread diameter of 9.0 mm (cylindrical portion diameter of 8.1 mm or more) placed at 735.50 N (75 kgf) Even considering that the maximum load (103.9N per suspension bolt) is tested, the load 3079N at the beginning of bending and the maximum tensile load 10493N are sufficient as a bolt connection structure for suspension bolts. It turned out to be a value.

(Embodiment 2) Next, a different embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a bolt connection structure for a suspension bolt used as a ceiling base material attachment attached to an attic of a reinforced concrete structure.
In this case, even if the temperature of the ceiling above the roof rises due to solar heat and the connecting tube 3 expands in the summer, the bolts sandwiching the fitted portion C of the threads 11 and 21 of the bolts 1 and 2 are sandwiched. From the outer peripheral surfaces 14 and 24 of 1, 2 to the connecting cylinder 3
It is necessary to have a structure that does not drop. In the example of FIG. 4, the dimensions of the inner peripheral surface 31 of the connection cylinder 3 are such that the outer peripheral surfaces 14, 2 of the bolts 1, 2 sandwiching the portion C where the screw threads 11, 21 are fitted.
4 is sized to be a clearance fit with a very small gap, but a nut 25 is fitted in advance to the lower bolt 2. Similar to the first embodiment, the connecting tube 3 is placed in advance on both screw bolts 1 on the upper side, and this connecting strip 3 is, as shown in FIG. 4, the portion C of the screw threads 11, 21 of the bolts 1, 21. It is held by being lowered in the axial direction to a position surrounding the outer peripheral surfaces 14, 24. Then, if the nut 25 is tightened until it engages with the lower end 34 of the connecting cylinder 3, and the connecting cylinder 3 thermally expands due to the temperature difference, it surrounds the fitted portion C of the threads 11, 21. It does not fall out of position.

(Embodiment 3) A further preferred embodiment of the present invention will be described with reference to FIGS. The upper long screw bolt 1'and the lower long screw bolt 2 in this example
′ Is the surface of the same kind of wire as illustrated in (Example 1) having an outer diameter of 10.0 mm, and the thread 1 of (Example 1)
1 and the thread angle, the number of threads, the outer diameter and the effective diameter are equal, and the shape of the thread and the roundness of the crests and valleys of the effective diameter are the same as the male thread (angle of the thread; 60 °, screw 16 per 25.4 mm number of threads, outer diameter: 9.525 mm,
Effective diameter: 8.494 mm, valley diameter: 7.463 mm, thread height: 1.031 mm, crest and valley roundness:
0.20 mm) is machined to obtain a tensile strength of 330 N / mm
^{It is 2} . Therefore, even when the male and female screws are fitted together, the screw threads 11 and 2 of the unified coarse screw 3 / 8-16UNC of (Example 1) and (Example 2) are formed.
1, there is no large gap between the threads 11 and 21, and the height of the hook is 1.0.
Since it is equal to 31 mm, it is 0.172 mm larger than 0.859 mm in (Example 1) and (Example 2).

As shown in FIG. 6, No. 3 uses a straight side type hydraulic press for drawing and has a nominal thickness of 1.6 mm.
JIS G 3141-1990 cold-rolled steel strip standard refining product SPCD-S D39 equivalent material, which is a connection tube made by machining, and one hole 35 through which the bolt 1 penetrates at the upper left end thereof. Bulge and cover 3 on the upper right
6 was drawn. Then, similarly to (Example 1), the left and right sides of the inner peripheral surface 31 are connected to the outer peripheral surface 1 of the bolts 1'and 2 '.
The semi-cylindrical surfaces 32, 32 inscribed in 4, 24 are parallel flat surfaces 33, 33 in the portion following the semi-cylindrical surfaces 32, 32, the major axis of which is the screw threads 11, 2 of the two bolts 1 ', 2'.
Bolts 1 ', 2 sandwiching a portion C in which 1 is fitted to each other
Approximately equal to the tank cross-section maximum length (in this example, the dimensions of the inner circumference 31 of the connection strip 3 are the outer circumferential surfaces 14, 24 of the respective bolts 1 ′, 2 ′ fitted with the threads 11, 21). An intermediate fit with respect to the dimension to be tied) and an axial length h = 20 mm.

The upper end of the upper long-screw bolt 1'described in [0026] is fixed and placed, and the connecting cylinder 3 of the preceding paragraph is preliminarily passed through the bolt 1 ', as shown in FIGS. Outer peripheral surfaces 14 of the bolts 1 ′, 2 ′ sandwiching the fitted portions C of the threads 11, 21 of the bolts 1 ′, 2 ′,
Push down to the position surrounding 24. In this example,
Even if the male threads are fitted with the same number of threads, outer diameter, and effective diameter as in Example 1, there is almost no gap between the threads 11, 21 because the shapes of the threads inside and outside the effective diameter are the same. , The cross-sectional area where the bolts 1 ', 2'interlock with each other becomes considerably wide. Therefore, the tensile force applied to the tips of both bolts 1 ′ and 2 ′ is evenly distributed and supported by the fitting portion C of the screw thread and the connecting tube 3. Even if the lower bolt 2 ′ receives an impact force from below or the bolt connecting structure is subjected to severe vibration stress, the bolt connecting structure of the present embodiment does not loosen. further,
Since the connection cylinder 3 is provided with the lid 36, the bolt 1 ′,
Even if the fitting between 2'and the connecting tube 3 is somewhat loose, there is no risk that the connecting tube 3 will shift downward or drop. Therefore, it is not necessary to make the tolerance accuracy of the connecting tube 3 as strict as in the first embodiment,
Easy to manufacture and connect. In this example, when the lengths 1 of the fitted portions C of the threads 11 and 21 are the same as in (Example 1) and the same test as described above is performed, the tensile strength is considerably larger than this. Should be obtained.

(Fourth Embodiment) Next, a further different embodiment of the present invention will be described with reference to FIG. In this example,
Tensile strength obtained by rolling an external thread made of the same kind of wire as in (Example 1) and having the same mountain shape as the nominal size of M10 of JIS B0205-1982 meters coarse thread over the entire length of the cylinder. 330 N / mm ²
The upper long screw bolt 1 and the lower long screw bolt 2 were used. Then, the thread 11 of the lower end 12 of the upper bolt 1 is replaced with the thread 21 of the upper end 22 of the lower bolt 2.
mm, the length 1 of the fitted portion C is increased, and the connecting cylinders 3 and 4 are provided at the front end portion and the rear end portion, respectively.
Covered.

The upper connecting cylinder 3 has the same structure as in the third embodiment, and has a nominal thickness of JIS G 3 of 1.6 mm.
141-1990 Standard tempered product for deep drawing of cold rolled steel strip
Hole 3 made by deep drawing from SPCE45 equivalent material
5 and those having a lid 36, the axial length _h 1: 30
mm, but the lower connecting cylinder 4 is JIS G 344
SFKM 13 of carbon steel pipe for machine structure of 5-1998
B-E-C (13 type cold finish electric resistance welded steel pipe having a tensile strength of 440 N / mm ² or more) was processed in the same manner as in (Example 2), and the left and right ends of the inner peripheral surface 41 were The semi-cylindrical surface portions 42, 42 of a size inscribed in the outer peripheral surfaces 14, 24 of the bolts 1, 2 are parallel flat portions opposed to the semi-cylindrical surface portions 42, 42, the major axis of which is the screw of the two bolts 1, 2. The bolts 1 and 2 sandwiching the portion C where the ridges 11 and 21 are fitted to each other are formed into an oval shape having a dimension slightly larger than the maximum cross-sectional length of the bolts 1 and 2, and are formed to have an axial length h ₂ = 35 mm.
The thread 25 of the nut 25 is JIS B 0205.
It is a hexagonal nut similar to that of the second embodiment except that the metric coarse screw M10 is used to fit the bolt 2.

In the same test as Example 1 in this example, the bolt connection structure was 19044.5N (1942k).
It was found to withstand tensile loads up to gf). This is because the tensile strength of the bolts 1 and 2 is large, the length of the fitted portion C of the threads 11 and 21 is as long as 1 = 80 mm, and the total length of the connecting cylinders 3 and 4 is h = h. ₁ + h ₂ = 30 + 35
This is because the thread ridges 11 and 21 are not damaged because the length is as long as = 65 mm, and the bolt 1 is ruptured at the root diameter portion near the chuck of the tester. As in this embodiment, the portion C where the threads 11, 21 are fitted together.
If the length of the suspension bolt is long, it is easy to adjust the length of the suspension bolt, and if the structure is such that the length 1 of the portion C and the total length h of the connecting cylinders 3 and 4 are long (Example 1) It can be used as a connection structure for bolts that receive a larger tensile load.

(Fifth Embodiment) Further, another embodiment of the present invention will be described with reference to FIGS. Also in this example, the same bolts 1 and 2 as in (Example 4) are used, and the screw threads 11 and 21 are used.
The length in the axial direction of the fitting portion C of 1 was increased to 1 = 70 mm.
Semi-cylindrical surfaces 32, 32 inscribed on the outer peripheral surfaces 14, 24 of
And the flat surfaces 3 facing each other with the portion C following them interposed therebetween.
The cross section consisting of 3 and 33 is oval, and the major axis is 2
Thickness t = 2.0 mm, which has a dimension slightly smaller than the maximum cross-sectional length of the bolts 1 and 2 sandwiching the portion C where the threads 11 and 21 of the two bolts 1 and 21 are fitted to each other, the axial length A continuous connecting tube 3 having a size h = 70 mm was used. Since the length of this connecting cylinder 3 is as long as h = 70 mm, the upper end portion of the STKM 13B-E-C equivalent of JIS G 3445-1988 machine structure carbon steel pipe having a thickness of 2.0 mm is shown in FIG. , 9 and bent inward to form a hole 35 and a lid 36. Also in this example,
Similar to (Example 4), the upper end 12 of the bolt 1 and the bolt 2
Even if a large tensile load is applied to the lower end 22 of the
The bolts 1 and 21 did not break, and the bolt 1 broke at the root diameter.

(Embodiment 6) Still another embodiment of the present invention and its test result will be described with reference to FIG.
In this example as well, the same bolts 1 and 2 as in (Examples 4 and 5) are used.
And a connection tube 3 similar to that of (Example 3) is used, but in this case, on the thread 11 of the rear end portion 12 of the upper bolt 1,
The short tip (80 mm) of the bolt 6 along this 62
The fitted screw threads 61, the thread 65 at its rear end 63, the screw thread 21 of the lower bolt 2 such that the upper bolt 1 and the axis is equal, the length 1 _{1 =} 35 nm,
1 ₂ = 40 mm are fitted and arranged, and each bolt 1, 6,
These bolts 1, 6 and 2 are integrally restrained by the continuous connecting cylinder 3 which is inscribed in the outer peripheral surfaces 14, 64 and 24 of 2. In this example, the total length of the fitted parts C of the threads 11 and 21 is as long as 1 = 35 + 40 = 75 mm, and the axial centers of the bolt 1 and the bolt 2 are coincident with each other. Even if a tensile load is applied to the bolt 12 and the lower end portion 22 of the bolt 2, the bolts 1 and 2 do not receive a bending moment. Therefore, the permanent extension of the bolt connection structure due to the bending of the bolts 1 and 2 does not occur. The maximum tensile load was 18181.5N (1854 kgf), and the bolt 1 fractured at the root diameter. This example is most suitable as a connecting structure for suspension bolts that receive a tensile force that is somewhat larger than that of ordinary suspension bolts such as attachments for ceiling base materials such as auditoriums and halls, and piping support in factories.

(Embodiment 7) Various embodiments of the present invention have been described above. However, in the present invention, the mountain shape of the bolts 1 and 2 or the shape of the connecting cylinder 3 is changed or the axial length of the connecting cylinder is changed. Can be carried out in various different embodiments within the scope described in [Claims], such as one in which the thread is slightly shorter than the length of the fitted portion.

[0035]

As described above, according to the present invention, when connecting a plurality of bolts, it is not necessary to use a special long nut or a turnbuckle, and an extremely simple bolt connecting structure can be obtained. Further, the connecting work is easy and is not a special work such as welding, so that anyone can easily connect the bolts. Moreover, if there is no risk of fire and you need to adjust the length of the suspension bolt,
It can be applied to those requiring a tensile strength that is somewhat larger than that of a normal bolt connection structure.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a “bolt connection structure” of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a vertical sectional view taken along the line III-III in FIG.

FIG. 4 is a vertical cross-sectional view showing one embodiment of the “bolt connection structure” of the present invention described in [Claim 3].

FIG. 5 is a perspective view showing one embodiment of the “bolt connection structure” of the present invention described in [Claim 4].

6 is a vertical cross-sectional view taken along the line VI-VI of FIG.

FIG. 7 is a longitudinal sectional view of an essential part showing one embodiment of the “bolt connection structure” of the present invention described in [Claim 6].

FIG. 8 is a perspective view showing an embodiment of the “bolt connection structure” of the present invention described in [Claim 7].

9 is a cross-sectional view taken along the line IX-IX in FIG.

FIG. 10 is a longitudinal sectional view of an essential part showing one embodiment of the “bolt connection structure” of the present invention described in [Claim 8].

[Explanation of symbols]

1 One-sided screw bolt 2 The other two-sided screw bolt 1'Long-screw bolts with different peak shapes 2'Long-screw bolt similar to 1'1 Connection tube 4 Other connection tube 6 Short bolt 11 Bolt 1 screw Mountain 12 Lower end of bolt 1 14 Outer peripheral surface of bolt 1 21 Thread of bolt 2 22 Upper end of bolt 2 23 Lower end of bolt 2 24 Outer peripheral surface of bolt 2 25 Nut that engages bolt 2 26 Nut 25
31 inner peripheral surface of the connecting cylinder 3 32 semi-cylindrical surface portion of the connecting cylinder 3 33 flat portion of the connection 3 34 lower end of the connecting cylinder 3 35 hole of the connecting cylinder 3 lid C of the connecting cylinder 3 screw thread 11, 21, 65, etc., which are fitted together l Total axial length of portion C t Thickness of connecting cylinder 3 Total axial length of connecting cylinder 3

Claims (8)

[Claims] 1. A single bolt having a rear end portion with a parallel screw having substantially the same total effective diameter, a helix angle of a helical winding, and a mountain shape of a screw thread, and the parallel screw at a tip end portion along the bolt. A plurality of bolts, parallel to each other, threaded together for a predetermined length, including other bolts, and surrounding each threaded portion of these bolts. A connection having a semi-cylindrical surface portion inscribed in the outer peripheral surface and a flat surface portion which is continuous with these semi-cylindrical surface portions and faces each other across the portion, and has an oval shape and has a predetermined thickness and an axial length close to the above portion. A bolt connection structure characterized by comprising a cylinder. 2. The bolt according to claim 1, wherein the inner peripheral surface of the bolt is provided with a connecting cylinder having a size that provides a tight fit with the outer peripheral surface of each of the bolts fitted with each other. Connection structure. 3. A nut fitted to at least one of the bolts, the nut engaging with a lower end portion of the connecting cylinder [claim 1] or [claim 2].
Bolt connection preparation. 4. The bolt connection structure according to claim 1 or 2, wherein a lid having one hole through which a bolt penetrates is provided at an end of the connection cylinder. 5. A hole through which a bolt penetrates is formed at an end portion of a connecting cylinder whose inner circumference is a size that is an intermediate fit or a clearance fit with respect to an outer peripheral surface of each bolt in which a screw thread is fitted. The bolt connection structure according to [claim 1] or [claim 4], characterized in that a lid provided is provided. 6. The axial length of a fitted portion of a screw thread is lengthened and the front and rear ends of both parallel screws arranged so as to sandwich the portion of each bolt [claim 2], respectively. To [Claim 5], the bolt connection structure according to [Claim 1], wherein the connection cylinder is covered. 7. A continuous [claim 2]-[claim 2] which increases the axial length of the engaged portion of the threads and has an axial length close to the engaged portion of the threads of each bolt. [5] The bolt connection structure according to [1], which is covered with any one of the connection cylinders. 8. A rear end of one bolt, and a tip of a short bolt along the rear end of the bolt, and another bolt along the short bolt on the same axis as the one bolt at the rear end of the short bolt. , The screw threads are fitted to each other by a predetermined length, and these bolts are integrally formed by the continuous connecting cylinder of any one of [Claim 2] to [Claim 5] inscribed in the outer peripheral surface of each bolt. The bolt connection structure according to claim 1, wherein the bolt connection structure is constrained to.