[DESCRIPTION] [Invention Title]

A REINFORCING BAR, A COUPLER OF THE REINFORCING BAR, AND AN ASSEMBLY AND A CONNECTION METHOD THEREOF [Technical Field]

The present invention relates to a reinforcing bar and a coupler capable of connecting the reinforcing bars in a longitudinal direction.

[Background Art] A method of connecting reinforcing bars comprises welding, overlapping, nut fastening and so forth. The overlapping cannot be used in the structure requiring high strength, and the welding is not suitable for the performance to be carried out on the spot. Since ends of the reinforcing bars should be machined on the spot, the nut fastening is very inconvenient. Also, the reinforcing bars are fastened to nuts by relatively rotating the nuts several to dozen times in the nut fastening. When two reinforcing bars are connected to each other in a longitudinal direction, it is inconvenient to rotate any one of the two reinforcing bars several to dozen times. Labor intensive working and significant times are required to connect the reinforcing bars in common reinforced concrete buildings. [Disclosure] [Technical Problem]

Therefore, the present invention has been made in view of the above-mentioned problems. l

An object of the present invention is to provide a reinforcing bar including a plurality of ribs, a plurality of protruding joints, and a recessed portion formed between the joints of the adjacent ribs, and a reinforcing bar coupler, in which after inner bosses of the reinforcing bar coupler are inserted therethrough while the reinforcing bar is inserted into the reinforcing bar coupler, the reinforcing bar coupler is relatively rotated with respect to the reinforcing bar to couple the reinforcing bar to the reinforcing bar coupler. [Technical Solution]

In order to achieve the above and other objects, there is provided a reinforcing bar comprising a rod having an about circular section, a plurality of ribs arranged on an outer surface of the rod at regular intervals and protruded in a longitudinal direction of the rod, a plurality of protruding joints from both sides of the ribs on the outer surface of the rod at regular intervals, and a recessed portion formed between the joints of the adjacent ribs.

With the construction of the reinforcing bar, the ribs and the joints increase the bond strength between the reinforcing bar and the concrete, and the ribs are formed on the reinforcing bar in a longitudinal length to improve tensile strength of the reinforcing bar. If the recessed portion formed between the joints of the adjacent ribs coincides with an inner boss of a reinforcing bar coupler, the reinforcing bar can be easily inserted into the reinforcing bar coupler. Upon the insertion, the reinforcing bar coupler and the reinforcing bar

are relatively rotated in order to insert the inner boss of the reinforcing bar coupler is inserted into the space between the joints. As a result, the present invention can easily couple two reinforcing bars in a longitudinal direction. The rib is provided with a groove at both sides thereof corresponding to the joint protruding position. This provides the reinforcing bar with a wavy surface, as well as the ribs and the joints, thereby increasing the bond strength between the reinforcing bar and the concrete and reducing consumption of the material which is not related with the strength of the reinforcing bar.

Preferably, the reinforcing bar is provided with two or three ribs.

In case of the reinforcing bar having a small diameter, two ribs may be formed, while, in case of the reinforcing bar having a large diameter, three ribs may be formed. In particular, in case of three ribs, even though the reinforcing bar is applied with bending force in any direction, the reinforcing bar can cope with the bending force. Therefore, the case of three ribs increases the bending force in all directions, as compared with the case of two ribs. The joint has a convex surface and a concave surface which are opposed to each other.

After the inner bosses of the reinforcing bar coupler are inserted between the adjacent joints, the inner bosses are supported by the concave surface or convex surface to prevent the inserted inner bosses from being escaped from the joint.

The convex surface has a first mostly protruding portion formed at a middle portion thereof, and a first depressed portion and a second depressed portion which are disposed at outer and inner sides of the first protruding portion. The concave surface has a mostly depressed portion of large arc shape, and a second protruding portion and a third protruding portion which are formed in parallel at an inside more than the mostly depressed portion.

The first depressed portion of the convex surface is to guide the insertion of the inner boss of the reinforcing bar coupler into the space between the adjacent joints. The inner boss inserted through the first protruding portion is seated in the second depressed portion to stably couple the reinforcing bar with the reinforcing bar coupler.

The first protruding portion prevents the seated inner boss from being escaped from the space between the adjacent joints. The third innermost protruding portion of the concave surface is to enable the inner boss inserted into the space between the adjacent joints through the first protruding portion to seat, and the second protruding portion interferes with the inner boss seated between the adjacent joints together with the first protruding portion to prevent the inner boss from being escaped from between the adjacent joints.

Preferably, the joints protruding from both sides of the rib at regular intervals are formed at alternative positions on the both sides.

This enables two reinforcing bars to be positioned and fixed at mostly adjacent to each other in the reinforcing bar coupler when the reinforcing bars are coupled to each other in a longitudinal

direction.

Preferably, the recessed portion is formed by making a corresponding portion of the rod in flat.

This is to smoothly insert the inner bosses of the reinforcing bar coupler and to stably insert a wedge.

Preferably, the rib has a height equal to that of the joint, and the rib and the joint have an about trapezoidal section in a direction perpendicular to a longitudinal direction thereof.

If the rib has the same height as that of the joint, it easily makes inside of the reinforcing bar coupler in a circular shape. If the reinforcing bar has a trapezoidal section, the fastening is smoothly performed by making the reinforcing bar coupler in a trapezoidal shape.

Preferably, the recessed portion has a width equal to or larger than an interval between the adjacent joints protruding from the side of the corresponding rib.

With the above construction, the inner boss of the reinforcing bar coupler can be firmly inserted between the adjacent joints of the rib of the reinforcing bar, and can be smoothly inserted when the inner boss is smoothly inserted along the recessed portion in a longitudinal direction of the reinforcing bar.

According to another aspect of the present invention, there is provided a reinforcing bar coupler comprising a tubular member having an about circular section, and a plurality of rows of inner bosses formed in a longitudinal direction on an inner surface of the

tubular member and arranged at regular intervals.

The reinforcing bar coupler is used for the above-described reinforcing bar. The inner boss is inserted along the recessed portion of the reinforcing bar, and the reinforcing bar and the reinforcing bar coupler are relatively rotated at a certain angle to insert the inner boss into the space between the joints protruding from the rib of the reinforcing bar, thereby easily coupling the reinforcing bars in a longitudinal direction.

The tubular member is provided with outer bosses at positions opposed to the inner bosses.

When the space between the recessed portion or the joints of the rib of the reinforcing bar are set to the orientation of the inner boss, the position of the inner boss can be easily checked out from the outside, and also the outer bosses increase the bond strength with the concrete.

A wedge groove is formed on one or either of both sides of the inner bosses at positions which are spaced corresponding to an interval between a recessed portion and a rib of a reinforcing bar.

A wedge can be fitted in the space formed by the recessed portion and the wedge groove after the reinforcing bar and the reinforcing bar coupler are connected to each other, thereby preventing the reinforcing bar and the reinforcing bar coupler from being rotated in an adverse direction.

A portion of the tubular member which corresponds to the wedge groove protrudes outwardly in a height corresponding to a

depth of the wedge groove.

A thickness of the portion of the tubular member which is provided with the wedge groove coincides with a thickness of the remaining portion of the tubular member to prevent the strength of the tubular member from being weakened. Also, the bonding strength between the reinforcing bar coupler and the concrete is increased by the outwardly protruding shape.

The reinforcing bar coupler comprises two or three rows of inner bosses. The reinforcing bar coupler can be fastened to the reinforcing bar with two or three ribs.

Preferably, the tubular member is provided at a middle portion thereof with a slit or through-hole communicating with an inside of the tubular member. When two reinforcing bars are connected to each other, it can be checked out whether two reinforcing bars are accurately disposed in the reinforcing bar coupler through the slit or through-hole. Also, the bond strength of two reinforcing bars is increased by introducing an adhesive such as epoxy through the slit or through-hole. According to still another aspect of the present invention, there is provided an assembly of a reinforcing bar and a reinforcing bar coupler comprising : the reinforcing bar including a rod having an about circular section; a plurality of ribs arranged on an outer surface of the rod at regular intervals and protruded in a longitudinal direction of the rod; a plurality of protruding joints from both sides of

the ribs on the outer surface of the rod at regular intervals; and a recessed portion formed between the joints of the adjacent ribs; the reinforcing bar coupler including a tubular member having an about circular section; a plurality of rows of inner bosses formed in a longitudinal direction on an inner surface of the tubular member and arranged at regular intervals; a wedge groove formed on one or either of both sides of the inner bosses at positions which are spaced corresponding to an interval between a recessed portion and a rib of a reinforcing bar; and a wedge inserted into a space formed by the recessed portion of the reinforcing bar and the wedge groove of the reinforcing bar coupler after the reinforcing bar is coupled to the reinforcing bar coupler.

According to another aspect of the present invention, there is provided a method of coupling a reinforcing bar and a reinforcing bar coupler, the method comprising inserting the reinforcing bar into the reinforcing bar coupler, with the recessed portion of the reinforcing bar corresponding to the inner bosses of the reinforcing bar coupler; relatively rotating the reinforcing bar coupler with respect to the reinforcing bar to insert the inner boss into a space between the joints of the rib; and inserting the wedge into a space defined by the recessed portion and the wedge groove. [Advantageous Effects]

With the above description, according to the reinforcing bar and the reinforcing bar coupler, and the method of coupling them, the present invention can increase the bond strength, and easily connect

the reinforcing bars on the spot. [Description of Drawings]

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view illustrating a reinforcing bar according to an embodiment of the present invention;

FIG. 2 is a front view of the reinforcing bar in FIG. 1; FIG. 3 is a plan view of the reinforcing bar in FIG. 1;

FIG. 4 is a side view of the reinforcing bar in FIG. 1; FIG. 5 is an enlarged view illustrating ribs and joints of the reinforcing bar in FIG. 1;

FIG. 6 is a perspective view illustrating a reinforcing bar coupler according to an embodiment of the present invention;

FIG. 7 is a side view of the reinforcing bar coupler in FIG. 6; FIG. 8 is a cross-sectional view taken along line A-B in the reinforcing bar coupler in FIG. 7; and

FIGs. 9 to 17 are views illustrating the process of fastening the reinforcing bar in FIG. 1 with the reinforcing bar coupler in FIG. 6. [Best Mode]

A reinforcing bar and a reinforcing bar coupler according to an embodiment of the present invention will now be described in detail with reference to accompanied drawings. FIG. 1 is a perspective view illustrating a reinforcing bar

according to an embodiment of the present invention. FIG. 2 is a front view of the reinforcing bar in FIG. 1. FIG. 3 is a plan view of the reinforcing bar in FIG. 1. FIG. 4 is a side view of the reinforcing bar in FIG. 1. FIG. 5 is an enlarged view illustrating ribs and joints of the reinforcing bar in FIG. 1. FIG. 6 is a perspective view illustrating a reinforcing bar coupler according to an embodiment of the present invention. FIG. 7 is a side view of the reinforcing bar coupler in FIG. 6. FIG. 8 is a cross-sectional view taken along line A- B in the reinforcing bar coupler in FIG. 7. The reinforcing bar according to an embodiment of the present invention will now be described with reference to FIGs. 1 to 5. A reinforcing bar 1 includes an elongated rod 11 having a circular section, and two ribs 12 protruding from both sides of the rod 11.

The respective ribs 12 is provided with a plurality of protruding joints 13 at regular intervals that are arranged in a direction perpendicular to a longitudinal direction. The plurality of joints 13 protruding from both sides of one rib 12 may be formed at the same position (see FIG. 2) or be formed at different positions (not shown), when viewing at a longitudinal direction of the rib 12. If the joints 13 are formed at the same position, a groove 17 is formed on each of the joints 13 protruding from both sides of the rib 12. Consequently, as well as the ribs 12 and the joints 13, the surface of the reinforcing bar is provided with more indented portions to improve the bond strength between the reinforcing bar and the concrete and reduce consumption of material at the portion that is

not associated with the strength of the reinforcing bar. If the joints 13 protruding from both sides of the reinforcing bar are formed at different positions, ends of two reinforcing bars 1 can come in close contact with each other when the reinforcing bars 1 are connected to each other by using a reinforcing bar coupler 2, which will be described hereinafter, in a longitudinal direction.

The rib 12 and the joint 13 are formed to have a trapezoidal section when viewing at the sections taken along lines a-a and b-b in FIG. 5, and have the same height. This corresponds to a trapezoidal section of an inner boss formed on the reinforcing bar coupler 2. The trapezoidal section can be easily manufactured as compared with a rectangular section. Also, when two members are relatively coupled to each other, the adjacent portion of two members guides the members to a proper position to smoothly connect the members. A recessed portion 14 is formed between the opposing joints

13 of two ribs 12. As shown in FIG. 4, if the recessed portion 14 formed on the circular rod 11 is formed in a flat shape, it firmly fixes a wedge 3 which will be described hereinafter, and guides the inner boss 23 of the reinforcing bar coupler 2. The recessed portion 14 has a width (See "x" in FIG. 3) equal to or wider than an interval (See "y" in FIG. 3) between the adjacent joints 13. This smoothly guides the inner boss 23 of the reinforcing bar coupler 2 when the inner boss 23 is inserted into the recessed portion 14, and also ensures well fit when the inner boss 23 is inserted into the space between the joints 13, to prevent free

movement of the inner boss 23 and thus increase the fixing force therebetween.

In this embodiment, the reinforcing bar 1 having two ribs 12 is described. If the reinforcing bar has a large diameter, the reinforcing bar may be provided with three ribs and joints to increase the fixing force, instead of that the sizes of the ribs 12 and the joints 13 are increased. In the case where the reinforcing bar 1 having larger diameter is used in the construction requiring more strength, the reinforcing bar coupler 2 has to have a thicker thickness to further increase the strength thereof.

Preferably, the joint 13 has a convex surface 16 and a concave surface 15 which are opposed to each other so that the joint is formed in a wave shape, rather than a straight shape, in view of firm fixation of the inner boss 23 formed on the reinforcing bar coupler 2. Since the convex surface 16 and the concave surface 15 of the opposing joints 13 of two ribs 12 are formed in an adverse direction, there is no orientation even though the reinforcing bar is faced in any direction.

In particular, the convex surface 16 has a first protruding portion 163 formed at the middle portion thereof, and a first depressed portion 161 and a second depressed portion 162 which are disposed at outer and inner sides of the first protruding portion. The concave surface 15 is formed in an arc shape, and has a mostly depressed portion 151 of large arc shape, and a second protruding portion 152 and a third protruding portion 153 which are formed in

parallel at an inside more than the mostly depressed portion 151. The second protruding portion 152 is disposed at the inside more than the first protruding portion 161.

The case that the inner boss 23 of the reinforcing bar coupler 2 is inserted into the space between the joints 13 will now be described with reference to FIG. 5. If the inner boss 23 is firstly inserted into the interval between the joints 13, the inner boss 23 is smoothly guided towards the concave surface 15 by the first depressed portion 161, and then passes between the first protruding portion 163 and the second protruding portion 152. In this instance, the distance between the first protruding portion 163 and the second protruding portion 152 is equal to or slightly larger than the diameter of the inner boss. As a result, when the inner boss 23 passes between the first protruding portion 163 and the second protruding portion 152, it allows an operator to feel the slightly stiff fit, so that the operator can seize the passage of the inner boss 23 between the first protruding portion 163 and the second protruding portion 152.

After the inner boss 23 passes between the first protruding portion 163 and the second protruding portion 152, the third protruding portion 153 prevents the inner boss 23 from going out if the inner boss 23 is applied with a force in a direction indicated by "c". Also, if the inner boss 23 is applied with a force in a direction indicated by "d", the inner boss 23 is seated in the second depressed portion 162 to prevent the inner boss 23 from going out. In case of the wavy shape formed by a simple concave

surface and a simple convex surface only, the reinforcing bar should be provided with at least two concave surfaces and at least two convex surfaces in order to prevent the boss from going out. However, the boss can be sufficiently fixed by only one concave surface and one convex surface in case of the shape as described above. More specifically, according to this embodiment in which the joint is formed by only one concave surface and one convex surface, since the joint is formed to have a thick and short shape, even a reinforcing bar having a small diameter can ensure the strength of the joint. Also, a reinforcing bar can have three ribs to increase the bond strength.

The reinforcing bar coupler 2 according to an embodiment of the present invention will now be described with reference to FIGs. 6 to 8. The reinforcing bar coupler 2 is a tubular member having a circular section, and includes two rows of inner bosses 23 formed in a longitudinal direction on an inner surface thereof.

The inner boss 23 is formed to have a trapezoidal section, and the shape of the inner boss 23 corresponds to the space (indicated by "y" in FIG. 3) between the joints 13 of the reinforcing bar 1. Preferably, two rows of 10 inner bosses 23 are formed on the inner surface of the reinforcing bar coupler 2. Intervals of the inner bosses 23 correspond to those of the joints 13 of the reinforcing bar

1 to fasten the inner bosses 23 to the intervals between the joints 13.

Although two rows of inner bosses are shown and described in this embodiment, a reinforcing bar coupler 2 which is connected

with a reinforcing bar having three ribs may be provided with three rows of inner bosses. That is, the number of rows of the inner bosses formed on the inner surface of the reinforcing bar coupler 2 corresponds to the number of the ribs or recessed portions. The tubular member 21 is provided with outer bosses 22 at positions opposed to the inner bosses 23. The outer bosses 22 are to allow the operator to seize positions of the inner bosses 23 by intuition, and to increase the bond strength with the concrete. Wedge grooves 24 and 25 are formed on both sides of the inner bosses 23 in a longitudinal direction. For example, the first wedge groove 24 is formed at the upper portion of the right inner boss 23 in FIG. 7, and the second wedge groove 25 is formed at the lower portion of the right inner boss 23. The first wedge groove 24 is formed at the lower portion of the left inner boss 23, and the second wedge groove 25 is formed at the upper portion of the left inner boss 23.

The outer surface of the tubular member 21 which corresponds to the wedge grooves 24 and 25 protrudes outwardly by a height corresponding to a depressed depth of the wedge groove. This is to prevent the strength of the reinforcing bar coupler 2 from being reduced since the portion of the tubular member 21 corresponding to the wedge grooves 24 and 25 is thin. Also, the bond strength with the concrete is increased by the outwardly protruding shape. The wedge grooves 24 and 25 are formed on both ends of the

tubular member 21, and may be formed in a fully depressed shape along a longitudinal direction of the tubular member 21. Otherwise, a middle portion of the wedge groove may be not depressed, but be flush with the inner surface of the reinforcing bar coupler 2, as shown in FIG. 8. The latter can further increase the strength of the reinforcing bar coupler 2.

Although not shown in the drawings, if a slit or through-hole communicating with the inside of the tubular member is formed in the center portion of the tubular member 21 of the reinforcing bar coupler 2 in a longitudinal direction, the inserted depth of the reinforcing bar is adjusted through the slit or through-hole so that the reinforcing bar is accurately inserted into the reinforcing bar coupler 2 by a half length thereof. Also, the reinforcing bar 1 and the reinforcing bar coupler 2 are firmly fixed by introducing epoxy through the slit or through-hole.

Although the reinforcing bar coupler including two rows of inner bosses is described, the reinforcing bar coupler including three rows of inner bosses may be provided with three rows of outer bosses and three rows of inner bosses and provided with wedge grooves 24 and 25 at both sides of each inner bosses.

A process of coupling the reinforcing bar 1 and the reinforcing bar coupler 2 will now be described.

FIGs. 9 to 17 are views illustrating the process of fastening the reinforcing bar in FIG. 1 with the reinforcing bar coupler in FIG. 6. Referring to FIG. 9, first of all, the reinforcing bar 1 is

inserted into one side of the reinforcing bar coupler 2, with the recessed portion 14 of the reinforcing bar 1 corresponding to the inner bosses 23 of the reinforcing bar coupler 2. In this instance, the operator can easily arrange the recessed portion 14 of the reinforcing bar 1 and the inner bosses 23 of the reinforcing bar coupler 2 by referring to the outer bosses 22 of the reinforcing bar coupler 2. Also, the inserted depth of the reinforcing bar 1 can be set to the center portion of the reinforcing bar coupler 2 through the slit or through-hole (not shown) formed at the middle portion of the reinforcing bar coupler. Since the recessed portion 14 is formed in a flat shape, and has a width larger than the interval between the joints 13 corresponding to the width of the inner boss 23, the inner boss 23 can be easily inserted along the recessed portion 14.

Next, the reinforcing bar coupler 2 is relatively rotated with respect to the reinforcing bar 1 (see FIG. 10) so that the inner bosses 23 of the reinforcing bar coupler 2 are inserted between the joints 13 of the reinforcing bar 1, as shown in FIG. 11.

FIGs. 11 and 12 show the state in which the reinforcing bar coupler 2 is rotated in a clockwise direction in FIG. 10, while FIG. 13 shows the state in which the reinforcing bar coupler 2 is rotated in a counterclockwise direction in FIG. 10.

Whatever the reinforcing bar coupler 2 is rotated in any direction, the inner bosses 23 are smoothly guided between the joints

13, as described and shown in FIG. 5. Then, when the inner boss 23 passes between the first protruding portion 163 and the second

protruding portion 152, it allows the operator to feel the slightly stiff fit, so that the operator can seize the passage of the inner boss 23 between the first protruding portion 163 and the second protruding portion 152. This feeling on the stiff fit can be visually achieved by the position of the outer bosses 23. Also, the inserted inner bosses 23 are not moved by the second depressed portion 162 or the third protruding portion 153, so that the inner bosses 23 can be maintained in a stable position. Since the wedge grooves 24 and 25 of the reinforcing bar coupler 2 are formed at both sides of the inner boss 23 by an interval corresponding to that between the recessed portion 14 and the rib 12 of the reinforcing bar 1, the wedge grooves 24 and 25 are opposed to the recessed portion 14 when the inner boss 23 is inserted between the joints 13 from the recessed portion 14. For example, if the reinforcing bar coupler 2 is rotated in a clockwise direction in FIG. 12, the first wedge groove 24 coincides with the orientation of the recessed portion 14. If the reinforcing bar coupler 2 is rotated in a counterclockwise direction, the second wedge groove 25 coincides with the orientation of the recessed portion 14. Since the wedge grooves 24 and 25 are formed on both sides of the inner bosses 23, the relative rotation of the reinforcing bar coupler 2 and the reinforcing bar 1 is not restricted.

In addition, in case of two ribs, the reinforcing bar coupler 2 is relatively rotated in the range of 90 degrees, contrary to screw engagement. Otherwise, in case of three ribs, the reinforcing bar

coupler 2 is relatively rotated in the range of 60 degrees.

Next, when the wedge 3 is inserted in the space formed by the first wedge groove 24 and the recessed portion 14, as shown in

FIG. 14, the wedge 3 simultaneously interferes with the wedge groove 24 and the joint 13 to prevent the relative rotation of the reinforcing bar coupler 2 and the reinforcing bar 1 (see FIG. 15).

This is identical to the case where the wedge 3 is inserted into the space formed by the second wedge groove 25 and the recessed portion 24. If the other end of the reinforcing bar is subjected to the above process in the same order, two reinforcing bars 1 can be connected to each other in a longitudinal direction by using the reinforcing bar coupler 2, as shown in FIG. 17.

Lastly, the bond strength between the reinforcing bar and the reinforcing bar coupler is further increased by introducing an adhesive such as epoxy through the slit or through-hole formed at the middle portion of the reinforcing bar coupler.

While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiment and the drawings. On the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims.

[Industrial Applicability] The present invention can be utilized in the field of civil

engineering and construction employing the reinforcing bars and the couplers therefor.