Patent Grant
11852183
The present invention generally relates to a press-fit nut for assembly, a press-fit nut-bolt assembly, and a construction method of steel-concrete composite structure using the same, more particularly to a press-fit nut for assembly, a press-fit nut-bolt assembly, and a construction method of steel-concrete composite structure using the same, whose process is simple and which do not create deformation during the installation process on the base material.
A Press-fit nut is also referred to as so-called a pem nut, a clinching nut, or a one-way nut. A press-fit nut is used when it is difficult to fasten a bolt and a nut at the same time or when it is difficult for a technician to reach a nut to fasten it. Especially, when a plate-shaped member is a base material, it is necessary to install bolts and nuts. At that moment, only one side of the base material is reachable while the other side of it has already been joined or is facing toward an unreachable location for the technician. In this case, the press-fit nuts are press-fitted into the base material in advance either before bolts and nuts are installed on the base material or when the base material is still reachable.
A normal nut can be welded on the base material M in advance, but welding may create brittle fracture (earthquake, vibration) because of changes in the material caused by its welding heat, and its welding quality heavily depends on the skill of the technician. In addition, welding has problems such as injury, danger, restriction of construction due to environment, CO2 generation, and fire.
Therefore, a nut having a press-fitting part 2 as shown in
The press-fit nut is first press-fitted to the inside the steel plate. Subsequently, a one-way bolt, a high tension washer, and a high tension nut are temporarily assembled. However, when the inner socket fixes a pin tail and the outer socket rotates a high tension nut in a share wrench, the pin tail may be broken due to torsion.
In general, since ridges of the press-fit nut and the ridges of the high tension nut are both made in the same direction during the fastening process, the press-fit nut is first fixed and then the high tension nut is to be tightened to fasten. So, it is very inconvenient to work. Therefore, it has been necessary to develop the technology to improve its structure so that both the press-fit nut and the high-tension nut can be fastened with one single tightening operation.
As shown in
The press-fit nut has problems such as its rapid plastic deformation and the brittle fracture of the base material due to the strong impact made when it is press-fitted into the base material. Press-fit nuts are widely used owing to their convenience and innovation, but they still need to be improved in their technology because of their above-mentioned problems at both their installation process and their maintenance of their solidity installation. Such technical improvement of them is more urgently required when considering the safety of the facility.
As shown in
The present invention provides a press-fit nut-bolt assembly, a method of constructing a steel-concrete composite structure using the same, and a press-fit nut for the assembly, so that the installation process is more convenient and the base material is not deformed and the stability of the steel-concrete composite structure is increased in installation of a press-fit nut-bolt assembly in construction field.
In an embodiment of the present invention, a press-fit nut-bolt assembly has a press-fit nut, a stud bolt, a counter nut, and a washer, wherein the press-fit nut comprises: a head part famed in a normal nut shape; and a press-fit part formed to extend from one of both sides of the head part and having an outer diameter of the head part reduced as it extends, and is inserted by press-fitting into a base material M which requires fastening, wherein the head part and the press-fit part have a hollow with ridges continuously formed therein, wherein the stud bolt includes: a body part penetrating the press-fit nut so as to be coupled with the press-fit nut; and a pin tail formed to extend from the end of the body part and coupled with a mechanism for rotating the body part, wherein the body part includes a first ridge part and a second ridge part which are formed on an outer surface of the body part along the length direction of the body part and formed to be spaced apart from each other, wherein the counter nut is disposed on the opposite side of the press-fit nut with the base material therebetween which the stud bolt penetrates so that the stud bolt penetrates the counter nut so as to be coupled with the counter nut, wherein the washer is disposed between the base material and the counter nut, and the stud bolt penetrate its center, wherein the pin tail is formed at an end of the second ridge part which is one of both ends of the body part, so that the press-fit nut is coupled with the first ridge part and the counter nut is coupled to the second ridge part, and the first ridge part and the second ridge part are opposite to each other in directions of their ridges.
Preferably, in another embodiment of the present invention, a method for constructing a steel-concrete composite structure using the press-fit nut-bolt assembly of the above embodiment includes steps of: perforating so as to insert the stud bolt into the steel material; press-fitting the press-fit nut so as to form a concentric circle with a hole formed by the perforation in the area where the perforation is made on a surface of the steel material to be bonded to concrete; installing the stud bolt, the counter nut, and the washer to the press-fit nut; pouring the concrete on the surface to be bonded; and adjusting the installation position of the stud bolt before curing the concrete so as to maximize the length of one of the first surplus section and the second surplus section, which is buried in the concrete, wherein there is no temporal precedence between the step of pouring concrete and the step of adjusting to maximize the length.
Furthermore, in another embodiment of the present invention, a press-fit nut comprises: a head part formed in a normal nut shape such as a polygonal column or a circular column, and having ridges on an inner surface of a hollow that penetrates between both sides thereof; and a press-fit part extending from one of both sides of the head part with decreasing in diameter, wherein the press-fit part has: a hollow at a center of the press-fit part, which continues to the hollow of the head part; and plate-shaped splines on a circumferential side of the press-fit part, which are aligned parallel in the protruding direction and closely to each other with predetermined interval, wherein the press-fit part includes: a front sector which is a portion between an end and a certain point; and a rear sector which is a portion between the certain point and a point in contact with the head part, wherein the splines are formed continuously in length direction from the front sector to the rear sector, wherein the front sector decreases in its diameter from a boundary with the front sector and the rear sector to an end of the front sector, and converges toward its center.
According to a press-fit nut-bolt assembly, a method of constructing a steel-concrete composite structure using the same, and a press-fit nut for the assembly of the embodiment described in the present specification, bolts are fastened easily and a stud bolt is fastened strongly as if a head was installed. And, the base material is prevented from bending even if a plurality of press-fitting nuts are installed at the plate-shaped base material. A plurality of nuts fastened at both ends of the stud bolt can be tightened in opposite directions at the same time even if the end of the stud bolt rather than the center of the stud bolt is gripped and rotated. So, the installation process can speed up. The advantage of the press-fit nut-bolt is highlighted as much as possible, and the adhesion between steel and concrete is remarkably enhanced.
The present invention will be described in detail by the following description based on the accompanying drawings.
As shown in
The stud bolt 20 is formed to be elongated as shown in
An embodiment of a pin tail is shown in
As shown in
The washer 40 is disposed between the base material M and the counter nut 30 as shown in
The pin tail 24 is typically formed at the end of the stud bolt so as to grip the stud bolt 20 so that an instrument such as a spanner for rotating a bolt can rotate the stud bolt 20.
In the embodiment shown in
Since the press-fit nut 10 is press-fitted to be fixed on the base material M, the counter nut 30 gets tightened finely penetrating into the base material M if the pin tail 24 is gripped and rotated with a tool when it is finally tightly fastened. So, the counter nut 30, the washer 40, and the base material M are pressed in this order.
Therefore, in the embodiment according to
However, when the pin tail 24 is directly gripped with a tool and rotated with a strong force, the outer surface of the pin tail 24 may be damaged and it is restricted to elongate the pin tail 24, so that constructability may deteriorate due to interference with surrounding facilities.
Accordingly, a connector member 50 may be further provided in order to improve the constructability, and the connector member 50 may have either the shape shown in
In the first embodiment of the connector 50 shown in
In the second embodiment of the connector 50 shown in
In the embodiments of
Meanwhile, the press-fit nut-bolt assembly according to the present invention can be made so that the first ridge part 22 may has different diameter from that of the second ridge part 23, as shown in
In particular, the body part 21 may have a step 21c that makes different diameters between both ends of the body part 21, and has first and second ridges 22 and 23 so that the ridge which has larger outer diameter is formed on the end of body part 21 which has larger diameter.
The press-fit nut-bolt assembly is composed in the above-described structure has two effects. First, it is easy to insert the stud bolt 20 if inserting its part that has the smaller diameter in the case that the stud bolt 20 is tried to insert into two base materials M joined together but the end of the stud bolt 20 is caught between the two base materials M.
Second, the stud bolt 20 without the bolt head can have the same performance as a stud bolt with a bolt head.
Both sides of the body part can be divided at the step 21c as shown in
When the base materials M are overlapped in two layers and the holes in the overlapping base materials M are slightly shifted from each, it is not easy to insert the stud bolt 20 because the stud bolt 20 is caught by the interface of the base materials M during insertion process. At this time, if the thinner part of the stud bolt 20 that has smaller outer diameter is first inserted as shown in
In addition that the step 21c facilitates insertion, a step 21c is formed at the boundary between the first body part 21a and the second body part 21b, so that the step 21c functions as the bolt head. The step 21c prevents the stud bolt 20 from being inserted any longer in the insertion direction once it is installed, so that it is prevented from loosening due to the change in both directions.
On the other hand, as shown in
In the conventional press-fit nut 1, ridges are formed continuously not only in the head part 3 but also in the hollow of the press-fit part 2, as shown in
Accordingly, as shown in
As shown in
The press-fit nut-bolt assembly according to the embodiment shown in
The press-fit ring 60 is a ring-shaped member, and is press-fitted to one side of the base material M, the other side of which the press-fit part is inserted into, so that one side of the base material M is deformed by the amount of deformation of the other side of it deformed by the press-fit part 120. So, the both sides of the base material M are deformed by the same amount of deformation. Therefore, as the press-fit part 120 is press-fitted to the base material M, it prevents the base material M from warping and bending due to excessive deformation of one side of it, so that the stress is uniformly applied over the entire base material M. Accordingly, as shown in
The press-fit nut 10 is composed of a head part 130 and a press-fit part 120 as shown in
The head part 130 is formed in a normal nut shape such as a polygonal column or a circular column, and is a member having ridges on the inner surface of the hollow 123 that penetrates between both sides of the head part 130. That is, the head part 130 is the same as a normal nut shown in
The press-fit part 120 is a protrusion part that protrudes with decreasing in diameter from one side of the head part 130. The press-fit part 120 has the hollow 123 at the center of the protrusion part, which continues to the hollow 123 of the head part 130. The press-fit part 120 has plate-shaped splines 124 on its circumferential side, which are aligned parallel in the protruding direction and closely to each other with predetermined interval, so that the press-fit part 120 is press-fitted and inserted into the base material M through which nuts and bolts are required to couple with each other.
The press-fit part 120 according to the embodiment shown in
In particular, the press-fit nut 10 has the front sector 1221 that decreases in diameter as it goes from the boundary with the rear sector 1222 or 1223 to the end of the front sector 1221 and converges toward the center.
Since the front sector 1221 is formed as shown in
This means that the clinching nut has the structure that is macroscopically streamlined in the press-fit direction, and has the grooves that is microscopically repeated in a direction perpendicular to the press-fit direction. When the clinching nut of this structure is press-fitted into the base material, the grooves that is microscopically repeated in the perpendicular direction can absorb the deformation force which the structure streamlined in the press-fit direction applies to the base material during the press-fitting process.
In other words, since the front sector 1221 is formed to converge toward its center as it goes toward its end as shown in
Further, in this case, the reduction rate at which the diameter of the front sector 1221 gradually decreases increases gradually as it goes from the boundary with the front sector 1221 and the rear sector 1222 or 1223 to the end of the front sector 1221. So, the surface of the front sector 1221 is curved in the longitudinal direction as shown in
Therefore, the shape as described above is not only makes it easy to press-fit the press-fit nut 10 into the base material M, but also prevents the brittle fracture owing to its easy plastic deformation, and creates a strong resistance force in the withdrawal direction since it is firmly inserted into the base material M.
In addition, the front sector 1221 and the rear sector 1222 or 1223 are connected by a curved surface, so that they eventually create a continuous shape without any step in the entire section which is press-fitted into the base material M. This constitutive feature reduces the physical resistance when the clinching nut is press-fitted into the base material M.
And, as shown in
Such deformation damage of the press-fit part 120 may cause the ridges formed in the hollow 123 at the center of the press-fit part 120 to be distorted, so that it may be going to make troubles when the stud bolt 20 is coupled with the ridges later.
The above-described problem is solved by making the front sector 1221 to decrease in curved shape in its diameter.
In addition, since the front sector 1221 decreases gradually in its diameter as it goes toward its end, it is easy to adapt to the tolerance of the press-fit hole formed in the base material M. It is excellent especially when used for very rigid building structures.
Two embodiments may be presented for the shapes of the rear sector 1222 or 1223.
The first embodiment for the shape of the rear sector 1222 or 1223 is as shown in
In this case, even if the width of the rear sector 1222 is kept constant, as described above, it is different from the conventional press-fit nut 10 in that the front sector 1221 converges to the center similar to a kind of bell shape in the present invention. The press-fit part 120 is press-fitted pushing the base material M laterally while the conventional press-fit nut 10 pushes in the base material M in the press-fit direction during the press-fitting process. So, the restoring force (RF) is applied laterally to the press-fit part 120, and the base material M firmly holds the outer circumferential surface of the rear sector 1222. Thus, the press-fit nut 10 according to the present invention can be firmly press-fitted and will not be loosened.
As shown in
In this second embodiment, the shape of the rear sector 1223 is similar to the inverted shape of the front sector 1221.
In case that the rear sector 1223 is formed in the inverted shape of the front sector 1221, the restoration area BA shown in
The front sector 1221 mainly pushes in the front and the side of the base material M as shown in F G. 20 when it is press-fitted. At this time, a local plastic deformation area (PDA) is created in the base material M due to the base material M that is pushed out to the side. The size of the plastic deformation area (PDA) may be either larger or smaller than that that shown in
However, since the plastic deformation area (PDA) is instantaneously formed, only the part of the base material M is deformed permanently due to plastic deformation while the other part of the base material M is not deformed with complete plastic deformation but obtains a restoring force (RF) to return to its original position at the moment when the front sector 1221 pushes in the base material M.
The part without complete plastic deformation has a restoring force (RF) to return to its original position when the press-fit part 120 has been already completely press-fitted into the base material M as shown in
The restoration area BA shown in
As described above, such a part formed by the base material M which was pushed back in becomes a restoration area BA that can act as a resistance force when the press-fit part 120 is pulled out of the base material M.
In addition, after it is press-fitted completely and the restoration area BA is formed, residual stress remains on the part of the base material M which is contacted with the boundary between the front sector 1221 and the rear sector 1223, so that the remained residual stress applies to the surfaces of the front sector 1221 and the rear sector 1223. However, since the front sector 1221 and the rear sector 1223 are connected to each other with a curved surface so as to evenly receive residual stress, it minimizes the chance that the press-fit unit 120 is locally deformed. And the press-fit unit 120 is more firmly coupled with the base material M.
In addition, since the plastic deformation area (PDA) shown in
The work hardening phenomenon is one of the metal reinforcing mechanisms in which the strength of the metal increases due to the increased dislocation density caused by the entanglement or concentration of microdislocations that worked as the driving force of the deformation at the area which was deformed after the deformation processing of the metal.
Therefore, when work hardening happens at metals, their workability reduces but their strength increases, so that obtained is the most desirable physical properties required for the base material M around the press-fit nut 10 that was press-fitted. So, when the front sector 1221 and the rear sector 1223 are integrally formed in a round shape, resistance to residual stress is increased and plus, the part of the base material M at the deformation area which was pushed in between the rear sector 1223 and the head part 130 so to be restored is not deformed unless the press-fit nut 10 is pulled out with a force that is much greater than the force applied during the press-fitting process. Thus, the coupling between the press-fit nut 10 and the base material M is extremely effectively reinforced.
Therefore, even if the press-fit part 120 is not made in a wedge or hook shape, the press-fit part 120 is firmly positioned. However, if the press-fit part 120 is manufactured in a wedge shape or a hook shape instead of the shape of the front section 1221 and the rear section 1223 according the present invention, the ridges of the internal hollow 123 can be deformed since the press-fit part 120 is vulnerable to residual stress because of its shape.
In addition, the reduction rate at which the diameter of the rear sector 1223 is gradually decreased may be equal to or greater than the reduction rate at which the diameter of the front sector 1221 is gradually decreased.
In particular, when the reduction rate at which the diameter of the rear sector 1223 gradually decreases is greater than the reduction rate at which the diameter of the front sector 1221 gradually decreases, the restoration area BA may incompletely fill the space between the rear sector 1223 and the head unit 130 as shown in
On the other hand, as shown in
Conventionally, in the construction of a structure in which steel and concrete are bonded, concrete is poured after stud bolts are joined to the steel by welding as shown in
However, in the case of fixing the stud bolt by welding as shown in conceptual views of
However, in the embodiment shown in
Such an action of increasing the adhesion of concrete by the stud bolts can be applied not only to H-shaped steel or built-up square steel pipes shown in the photograph of
At this time, the determination of the first surplus section S1 and the second surplus section S2, i.e., the determination of the extent to which the stud bolts 20 are inserted into the square steel pipe or beyond the steel plate can be made before the concrete is cured.
Alternatively, it may be configured according to the modified embodiment as shown in
As shown in
The press-fit nut 10 and the counter nut 30 are not installed with a steel material therebetween as shown in
The first surplus section S1 and the second surplus section S2 are formed at one end and the other of the stud bolt 20 respectively to face each other as shown in
On the other hand, a method for constructing a steel-concrete composite structure using the above-described press-fit nut-bolt assembly will be briefly described since it mostly overlaps with the above-described description.
The method for constructing a steel-concrete composite structure using the press-fit nut-bolt assembly includes steps of: perforating so as to insert the stud bolt 20 into a steel material; press-fitting the press-fit nut 10 so as to form a concentric circle with the hole formed by the perforation in the area where the perforation is made on the surface of the steel material to be bonded to concrete; installing the stud bolt 20, the counter nut 30, and the washer 40 to the press-fit nut 10; pouring the concrete on the surface to be bonded; and adjusting the installation position of the stud bolt 20 before curing the concrete so as to maximize the length of one of the first surplus section S1 and the second surplus section S2, which is buried in the concrete, wherein there is no temporal precedence between the step of pouring concrete and the step of adjusting to maximize the length.
Here, in the step of installing the stud bolt 20, the counter nut 30, and the washer 40, a stud bolt 20 having a bolt head 25 formed at its end is preferably used, and the stud bolt 20 is installed so as to dispose the bolt head 25 on the side of the steel material which the concrete is bonded to, and the counter nut 30 is installed in close contact with the outer surface of the press-fit nut 10.
The technical idea described above is not limited by the embodiments and the accompanying drawings. It will be obvious for those who have common knowledge in the technical field to which the present technical idea belongs that various substitutions, modifications and changes are possible within the scope not departing from the above technical idea.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2019-0113932 | Sep 2019 | KR | national |
| 10-2019-0113933 | Sep 2019 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2020/012570 | 9/17/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/054744 | 3/25/2021 | WO | A |
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| Number | Date | Country | |
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| 20220003259 A1 | Jan 2022 | US |
