WO2004079119A1

WO2004079119A1 - Reinforcing bar coupler

Info

Publication number: WO2004079119A1
Application number: PCT/KR2004/000457
Authority: WO
Inventors: Yong Keun Kim
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-03-05
Filing date: 2004-03-04
Publication date: 2004-09-16
Anticipated expiration: 2005-09-05
Also published as: KR100691756B1; KR20040078819A

Abstract

The object of this invention is to provide a reinforcing bar coupler which includes a sleeve (2), a cover unit (3), and a wedge (4), and couples reinforcing bars (1, 1a) in a mechanical coupling method, thus ensuring a convenient coupling operation, and allowing the reinforcing bars to be firmly coupled to each other. The reinforcing bar coupler uses a wedge action of a conventional reinforcing bar coupler, and allows reinforcing bars to be more firmly coupled to each other, accomplishes a compatible structure, allows a coupling operation to be conveniently executed, and allows a uniform coupling operation to be carried out regardless of workers. Further, the reinforcing bar coupler of this invention can be used to couple the reinforcing bars to each other, regardless of a shape of latitudinal ribs (12) of the reinforcing bars.

Description

REINFORCING BAR COUPLER

Technical Field

The present invention relates, in general, to reinforcing bar couplers and, more particularly, to a reinforcing bar coupler which includes a sleeve, a cover unit, and a wedge, and couples reinforcing bars in a mechanical coupling method when the reinforcing bars are to be coupled to each other in reinforced concrete work, thus ensuring a convenient coupling operation, in addition to allowing the reinforcing bars to be firmly coupled to each other.

Background Art

Since reinforcing bars are produced at certain unit lengths from factories for convenient transportation and work, the reinforcing bars are required to be coupled to each other in reinforced concrete construction. Thus, there have been developed various methods of coupling the reinforcing bars, for example, a lap-joint process, a gas pressure welding process, a thread-joint process, etc. Of these, the lap-joint process, which is carried out in such a way that ends of reinforcing bars are lapped along certain lengths thereof and the lapped ends of the reinforcing bars are bound with binding wires, is predominantly used. However, the lap-joint process has a problem in that the coupled state of the lapped parts of the reinforcing bars is maintained not by the binding wires but by reinforced concrete, so that the coupled portion of the reinforcing bars is weaker in strength than the remaining parts of the reinforcing bars. Further, the lap- joint process has another problem in that the reinforcing bars must be lapped at certain lengths, thus causing a waste of reinforcing bars .

Another process, gas pressure welding process is carried out as follows. That is, ends of reinforcing bars are butted on each other, and the ends of the reinforcing bars are welded to each other by an oxy acetylene gas flame. However, the gas pressure welding process is problematic in that it is complicated and takes longer. Further, the welded portion of the reinforcing bars may become weakened by heat.

As another process of coupling reinforcing bars is used the thread-joint process, which will be described in the following. An end of each of the reinforcing bars to be coupled to each other is threaded to have a taper or parallel male thread. The ends of the reinforcing bars are coupled to each other by a coupler which has, on both ends of an inner surface thereof, a taper or parallel female thread. However, the thread-joint process is problematic in that it is difficult to thread a reinforcing bar. Further, the thread-joint process has another problem in that the end of the reinforcing bar having the thread is thinner than the remaining part of the reinforcing bar, so that the coupled portions of the reinforcing bars are weaker in strength than the remaining parts of the reinforcing bars.

In order to solve the problems of the conventional joint processes, that is, to enhance efficiency of the coupling operation and prevent the coupled portion of the reinforcing bars from being weaker than the remaining parts of the reinforcing bars, there was proposed Patent Appln. No. PCT/KR02/00190, which was filed by the applicant of the present invention, and entitled "REINFORCING BAR COUPLING". According to the Patent Appln. No. PCT/KR02/00190, the bar coupling operation is simplified by applying the principle of a wedge. Thus, the reinforcing bars are firmly coupled to each other by a simple hammering tool.

However, the reinforcing bar coupler according to Patent Appln. No. PCT/KR02/00190 has problems as follows. In the reinforcing bar coupler, a plurality of rib insert grooves are provided on an inner surface of each of a sleeve and a cover unit so that latitudinal ribs of reinforcing bars are inserted into the corresponding rib insert grooves . Further, an additional rib insert groove is provided between adjacent rib insert grooves so that the reinforcing bar coupler is utilized to couple the reinforcing bars to each other, regardless of whether the latitudinal ribs of the reinforcing bars have a circular or semicircular shape. However, in the case of a reinforcing bar having a smaller diameter, a pitch between adjacent latitudinal ribs is small, so that it is difficult to form an additional rib insert grooves. Further, the cover unit includes a bar compressing part and a wedge contacting part. An uneven surface is formed on each of the bar compressing part and the wedge contacting part to engage with the reinforcing bars and the wedge, respectively. Thus, the cover unit is received in the sleeve while accommodating the latitudinal ribs of the reinforcing bars, and further, the cover unit is sufficiently wedged by the wedge, thus providing a stable structure. However, the reinforcing bar coupler has a problem in that the number of elements is increased, so that it is more complicated to execute the bar coupling operation. The reinforcing bar coupler has another problem in that a worker can not confirm the insertion depth of a reinforcing bar, so the insertion depth of the reinforcing bar may be changed depending on a worker, thus leading to an undesirable coupling.

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a reinforcing bar coupler, which improves the reinforcing bar coupler disclosed in PCT/KR02/00190, thus allowing reinforcing bars to be more firmly coupled to each other, accomplishing a compatible structure, allowing a coupling operation to be conveniently executed, and allowing a uniform coupling operation to be carried out regardless of workers . In order to accomplish the above object, the present invention provides a reinforcing bar coupler, which is constructed so that rib insert grooves of each of a sleeve and a cover unit are provided at the same pitch as latitudinal ribs of reinforcing bars to be coupled to each other, and a length of the cover unit is longer than the sleeve by a half of a pitch of adjacent latitudinal ribs of the reinforcing bars, and an additional rib insert groove is provided on each of both edges of a bar seating part, and an outer surface of the cover unit and a surface of a wedge contacting the cover unit are respectively formed as a parallel surface. Thus, the reinforcing bar coupler of this invention can be used to couple the reinforcing bars to each other, if only the reinforcing bars have the latitudinal ribs of the same shape regardless of whether the latitudinal ribs of the reinforcing bars have a circular or semicircular shape. Further, a central depression is provided at a center of each of facing surfaces of the sleeve and the cover unit so that the inner diameter of each of the central depressions of the sleeve and the cover unit is larger than the outer diameter of the latitudinal ribs of each reinforcing bar, thus allowing the reinforcing bars to be received in the sleeve and coupled to each other without an additional process of finishing leading ends of the reinforcing bars, although the leading ends of the reinforcing bars are undesirably bent or projected during a bar cutting process. The wedge of the reinforcing bar coupler which wedges the cover unit, comprises a single wedge, thus reducing the number of elements, and thereby being convenient to couple the reinforcing bars to each other. Further, a scale rule is provided on a predetermined portion of the wedge to allow a worker to confirm an insertion depth of each reinforcing bar, thus allowing the reinforcing bars to be firmly and evenly coupled to each other, in addition to ensuring an easy post-inspection. Furthermore, a plurality of grooves are provided along inner and outers surfaces of the wedge, thus reducing friction between the wedge and the sleeve when the wedge is fitted into the sleeve, therefore allowing the wedge to be sufficiently fitted into the sleeve, and accomplishing firm bar coupling. Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a reinforcing bar coupler, according to a first embodiment of the present invention;

FIG. 2 is a side view of the reinforcing bar coupler of FIG. 1, in which two reinforcing bars are coupled to each other by the reinforcing bar coupler;

FIG. 3 is a sectional view of the reinforcing bar coupler of FIG. 1, in which the reinforcing bars are coupled to each other by the reinforcing bar coupler; FIG. 4 is a sectional view of the reinforcing bar coupler according to the first embodiment, in which the reinforcing bar coupler is used to couple reinforcing bars having semicircular latitudinal ribs which are arranged around longitudinal ribs to be offset from each other; FIG. 5 is a perspective view of the reinforcing bar coupler of FIG. 1;

FIG. 6 is an exploded perspective view of a reinforcing bar coupler, according to a second embodiment of the present invention; FIG. 7 is a side view of the reinforcing bar coupler of FIG. 6, in which two reinforcing bars are coupled to each other by the reinforcing bar coupler;

FIG. 8 is a sectional view of the reinforcing bar coupler of FIG. 6, in which the reinforcing bars are coupled to each other by the reinforcing bar coupler;

FIG. 9 is a sectional view of the reinforcing bar coupler according to the second embodiment, in which the reinforcing bar coupler is used to couple reinforcing bars having semicircular latitudinal ribs which are arranged around longitudinal ribs to be offset from each other; and

FIG. 10 is a perspective view of the reinforcing bar coupler of FIG. 6.

Best Mode for Carrying Out the Invention

Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components .

FIGS. 1, 2, 3 and 5 are an exploded perspective view, a side view, a sectional view, and a perspective view of a reinforcing bar coupler, according to a first embodiment of the present invention, respectively. The reinforcing bar coupler includes a sleeve 2, a cover unit 3, and a single wedge 4.

The sleeve 2 has a cylindrical shape, and has a sectional area enough to accommodate two reinforcing bars 1 and la with a predetermined clearance. The reinforcing bars 1 and la are axially inserted into the sleeve 2 through inlets provided at both ends of the sleeve 2. A plurality of latitudinal ribs 22 and a plurality of longitudinal ribs 21 are provided on an outer surface of the sleeve 2 to correspond to latitudinal ribs 12 and longitudinal ribs 11 of the reinforcing bars 1 and la, thus increasing a coupling force between the reinforcing bars 1 and la and concrete. A bar seating part 24 having a semicircular cross-section is provided on an inner surface of the sleeve 2, and has a diameter which is slightly larger than each reinforcing bar 1, la so that the reinforcing bars 1 and la are seated on the bar seating part 24. Further, a plurality of rib insert grooves 26 are provided on the bar seating part 24 at the same pitch as the latitudinal ribs 12 of the reinforcing bars 1 and la so that the latitudinal ribs 12 of the reinforcing bars 1 and la are inserted into the corresponding rib insert grooves 26. Thereby, the sleeve 2 is integrally coupled to the reinforcing bars 1 and la, thus preventing the reinforcing bars 1 and la from being undesirably moved. A central depression 27 is provided at a center of the bar seating part 24 to receive the reinforcing bars 1 and la, even when leading ends of the reinforcing bars 1 and la are undesirably bent or projected during a bar cutting operation. In this case, the central depression 27 has a shape similar to the rib insert grooves 26, but is slightly deeper and wider than the rib insert grooves 26.

A holding part 25 having a semicircular cross-section upwardly extends from the bar seating part 24 to hold the cover unit 3. A diameter of the holding part 25 is slightly larger than an outer diameter of each longitudinal rib 11 of each reinforcing bar 1, la, thus allowing the cover unit 3, which will be described in detail hereinafter, to be easily accommodated in the holding part 25 while sufficiently covering the reinforcing bars 1 and la. A surface of the holding part 25, which faces a parallel surface 33 of the cover unit 3 and contacts a slant surface 45 of the wedge 4, is inclined in a direction from a first end to a second end of the sleeve 2, thus forming a single slant surface 23 to contact the slant surface 45 of the wedge 4. Further, a serrated part (not shown) is provided at a predetermined portion of the slant surface 23 to engage with a serrated part (not shown) of the wedge 4. The cover unit 3 having a semi-cylindrical shaped groove, functions to cover the reinforcing bars 1 and la seated on the bar seating part 24 of the sleeve 2, and further, to compress the reinforcing bars 1 and la in cooperation with the wedge 4 that will be described in detail hereinafter. A length of the cover unit 3 is longer than the sleeve 2 by a half of a pitch between adjacent latitudinal ribs 12 of each reinforcing bar 1, la, while a width of the cover unit 3 is determined so that the cover unit 3 is easily inserted into the holding part 25. Further, a bar seating part 31 is provided on an inner surface of the cover unit 3 to have the same shape as the bar seating part 24 of the sleeve 2. A plurality of rib insert grooves 32, which have the same shape as the rib insert grooves 26 of the sleeve 2, are provided on the bar seating part 31 at the same pitch as the latitudinal ribs 12 of each reinforcing bar 1, la. A central depression 35 is provided at a center of the bar seating part 31 to have the same shape as the central depression 27 of the sleeve 2. Further, a parallel surface 33 is formed on an outer surface of the cover unit 3. A serrated part 34 is provided at a predetermined portion of the parallel surface 33 to engage with a serrated part 43 of the wedge 4 which will be described in the following.

The wedge 4 has a shape of a longitudinal rectangular plate which is tapered to an end thereof. The wedge 4 is introduced into a gap between the parallel surface 33 of the cover unit 3 and the slant surface 23 of the sleeve 2 through the inlets provided at the both ends of the sleeve 2. In this case, the wedge 4 compresses the cover unit 3 toward the reinforcing bars 1 and la while being supported by the sleeve 2. A length of the wedge 4 is almost equal to the cover unit 3. A surface of the wedge 4 contacting the parallel surface 33 of the cover unit 3 forms a parallel surface 42 without being inclined. The serrated part 43 is provided at an end of the parallel surface 42 to engage with the serrated part 34 of the cover unit 3. Further, a plurality of grooves 44 are provided along the parallel surface 42 to reduce friction between the parallel surface 42 of the wedge 4 and the parallel surface 33 of the cover unit 3, thus allowing the wedge 4 to be easily inserted between the outer surface of the cover unit 3 and the slant surface 23 of the sleeve 2.

A slant surface 45 is provided at a position opposite to the parallel surface 42 of the wedge 4 so that a thickness of the wedge 4 is reduced in a direction from a first end to a second end of the wedge 4. The slant surface 45 of the wedge 4 contacts the slant surface 23 of the sleeve 2, thus compressing the cover unit 3 toward the reinforcing bars 1 and la. Further, the serrated part (not shown) is formed at a predetermined portion of the slant surface 45 to engage with the serrated part (not shown) of the slant surface 23 of the sleeve 2. A plurality of grooves 44 are provided along the slant surface 45 to reduce friction between the slant surface 45 of the wedge 4 and the slant surface 23 of the sleeve 2, thus allowing the wedge 4 to be easily inserted into the sleeve 2. Further, a scale rule 41 with a predetermined scale interval is provided along the slant surface 45 of the wedge 4. Thus, when a worker desires to couple reinforcing bars of the same standard which are produced by the same manufacturing company, the worker can insert the wedge 4 between the slant surface 23 of the sleeve 2 and the parallel surface 33 of the cover unit 3 by a predetermined reference depth, while confirming the scale rule 41. In this way, following coupling operations can be executed so that reinforcing bars are always inserted into the sleeve 2 by a predetermined insertion depth. Thus, the scale rule 41 allows the evenly coupled reinforcing bars to be obtained, in addition to ensuring an easy post-inspection.

According to the first embodiment of this invention, the reinforcing bar coupler includes a single wedge 4 of which length is almost equal to the cover unit 3. Thus, the reinforcing bar coupler of the first embodiment allows the number of elements to be reduced, thus being easy to manufacture and being convenient to couple reinforcing bars to each other.

FIG. 4 shows the design of the reinforcing bar coupler, according to the first embodiment of this invention. That is, even when reinforcing bars 1 and la to be coupled to each other have semicircular latitudinal ribs 12 which are arranged around the longitudinal ribs 11 to be offset from each other, any end of the cover unit 3 is not retracted into the sleeve 2. Thus, the ends of -the reinforcing bars 1 and la are efficiently compressed by the cover unit 3 which is completely supported by the sleeve 2.

As such, in order to provide a reinforcing bar coupler which can be used to couple the reinforcing bars 1 and la, regardless of whether the latitudinal ribs 12 of the reinforcing bars 1 and la have a circular shape or a semicircular shape, the rib insert grooves 26 of the sleeve

2 and the rib insert grooves 32 of the cover unit 3 are positioned at the same pitch as the latitudinal ribs 12 of the reinforcing bars 1 and la. Further, the cover unit 3 has a length which is longer than the sleeve 2 by a half of a pitch of adjacent latitudinal ribs 12. A rib insert groove 32 is additionally provided on each of both edges of the bar seating part 31, thus allowing all the latitudinal ribs 12 of the ends of the reinforcing bars 1 and la to be inserted into the rib insert grooves 32, regardless of the shape of the latitudinal ribs 12. Further, the parallel surface 33 provided on the outer surface of the cover unit

3 is formed not as a slant surface but as a flat surface, and the parallel surface 42 of the wedge 4 contacting the cover unit 3 is formed not as a slant surface but as a flat surface. Next, the cover unit 3 is installed in the sleeve 2 so that any end of the cover unit 3 is not retracted into the sleeve 2. In such a state, when the wedge 4 is fitted between the outer surface of the cover unit 3 and the slant surface 23 of the sleeve 2, the wedge 4 is supported by the slant surface 23 of the sleeve 2. Thus, the wedge 4 compresses an entire portion of the parallel surface 33 of the cover unit 3, so that both ends of the cover unit 3 are supported by the sleeve 2, thus accomplishing perfect bar coupling. In a detailed description, when the cover unit 3 is formed to have the same length as the sleeve 2, in the same manner as the conventional reinforcing bar coupler, any end of the cover unit 3 may be retracted into the sleeve 2 according to a position of the latitudinal ribs 12 of the reinforcing bars 1 and la. In this case, the cover unit 3 cannot completely compress the ends of the reinforcing bars 1 and la. Therefore, such a reinforcing bar coupler may not completely receive the ends of the reinforcing bars 1 and la to be coupled to each other, according to a position of the latitudinal ribs 12 of the reinforcing bars 1 and la, thus having poor compatibility.

Meanwhile, in case where the outer surface of the cover unit 3 is formed not as a parallel surface but as a slant surface, the first end of the cover unit 3 which is formed thin at first becomes excessively thin. At this time, the first end of the cover unit 3 is very weakened. Conversely, when the cover unit 3 is constructed so that the first end thereof is thick, the second end of the cover unit 3 becomes excessively thick. In this case, a volume of the sleeve 2 must be increased to receive the cover unit 3, thus leading to an undesirable structure. Therefore, when the outer surface of the cover unit 3 is formed as the parallel surface and the cover unit 3 has a proper thickness to have a higher strength than the reinforcing bars, the entire portion of the cover unit 3 has an equal thickness and a reinforcing bar coupler having a stable structure is accomplished.

The operation of the reinforcing bar coupler according to the first embodiment of this invention will be described in the following. First, one reinforcing bar 1 is inserted into the sleeve 2 to be seated on the bar seating part 24, until the reinforcing bar 1 reaches the central depression 27. During the insertion of the reinforcing bar 1, the reinforcing bar 1 is adjusted so that the latitudinal ribs 12 of the reinforcing bar 1 are securely inserted into the corresponding rib insert grooves 26 of the bar seating part 24. Thereafter, the other reinforcing bar la is inserted into the sleeve 2, in the same manner as the reinforcing bar 1. Next, the cover unit 3 is introduced into the holding part 25 of the sleeve 2 to cover the ends of the reinforcing bars 1 and la. At this time, a worker grasps an end of the cover unit 3 which is longer than the sleeve 2 by a half of the pitch of adjacent latitudinal ribs 12 of each reinforcing bar 1, la. Next, the cover unit 3 is inserted into the central depression 35 of the sleeve 2, starting from a leading end of the cover unit 3, so that an end of the cover unit 3 is slightly projected out of the sleeve 2 or the end of the cover unit 3 corresponds to an end of the sleeve 2. In this case, all the latitudinal ribs 12 of the ends of the reinforcing bars 1 and la are inserted into the corresponding rib insert grooves 32. Thereafter, the wedge 4 is inserted into a gap between the slant surface 23 of the sleeve 2 and the parallel surface 33 of the cover unit 3, starting from the sharp end of the wedge 4. Subsequently, the wedge 4 is hammered or fitted using a hammering tool or a hydraulic jack. Thereby, the bar coupling operation is completed.

When the bar coupling operation is completed, the slant surface 23 of the sleeve 2 is in close contact with the slant surface 45 of the wedge 4. Thus, the cover unit 3 strongly compresses the reinforcing bars 1 and la so that the reinforcing bars 1 and la are firmly coupled to each other. That is, the reinforcing bars 1 and la are stably held in the sleeve 2 by a wedge action. Further, the serrated part 34 of the cover unit 3 engages with the serrated part 43 of the wedge 4, thus preventing the wedge 4 from being unexpectedly removed from the sleeve 2, therefore preventing undesirable bar coupling.

FIGS. 6, 7, 8 and 10 are an exploded perspective view, a side view, a sectional view, and a perspective view of a reinforcing bar coupler, respectively, according to a second embodiment of the present invention. The general construction of the reinforcing bar coupler of the second embodiment remains the same as the reinforcing bar coupler of the first embodiment. However, the reinforcing bar coupler of the second embodiment includes a sleeve 2a, a cover unit 3a, and a pair of wedges 4a, different from the reinforcing bar coupler of the first embodiment. Thus, both sides of the cover unit 3a are wedged by the pair of wedges 4a.

Each of the pair of wedges 4a has a length corresponding to a half of a length of the sleeve 2a. A plurality of grooves 44 and serrated parts 43 are provided on the parallel surface 42 and the slant surface 45 of each wedge 4a.

As such, since the wedge 4a comprises a pair of wedges 4a, two slant surfaces 23 are provided on an inner surface of the sleeve 2a to face the bar seating part 24 of the sleeve 2a. The two slant surfaces 23 are inclined so that a diameter of an interior of the sleeve 2a is increased from a center to both ends of the sleeve 2a. Thus, the pair of wedges 4a are fitted into the corresponding slant surfaces 23 of the sleeve 2a. Further, a serrated part is formed on each slant surface 23 to engage with the serrated part of an associated wedge 4a.

Further, since the wedge 4a comprises a pair of wedges, two serrated parts 34 are formed on both ends of the parallel surface 33 of the cover unit 3a to engage with the serrated parts of the corresponding wedges 4a.

FIG. 9 is a view corresponding to FIG. 4, to show the design of the reinforcing bar coupler, according to the second embodiment of this invention. That is, even when reinforcing bars 1 and la to be coupled to each other have semicircular latitudinal ribs 12, the cover unit 3a is always supported by the sleeve 2a and ends of the reinforcing bars 1 and la inserted into the sleeve 2a are completely compressed. Thus, the reinforcing bar coupler of FIG. 9 can be applied to couple the reinforcing bars 1 and la to each other, regardless of whether the latitudinal ribs 12 of each reinforcing bar 1, la have a circular shape or a semicircular shape, like the reinforcing bar coupler of FIG. 4. In a detailed description, the outer surface of the cover unit 3a is formed as the parallel surface 33, and a surface of each wedge 4a contacting the parallel surface 33 of the cover unit 3a is also formed as the parallel surface 42. Further, the cover unit 3a is longer than the sleeve 2 by a half of a pitch between adjacent latitudinal ribs 12 of the reinforcing bars 1 and la. A rib insert groove 32 is additionally provided on each of both edges of the bar seating part 31. Thus, when the cover unit 3a is inserted into the sleeve 2a in such a way that the latitudinal ribs 12 of the reinforcing bars 1 and la are inserted into the corresponding rib insert grooves 32 and any end of the cover unit 3a is not retracted into the sleeve 2a, angles and clearance between the slant surfaces 23 of the sleeve 2a and the parallel surface 33 of the cover unit 3a are always identical. Thus, the wedges 4a are inserted into the sleeve 2a by the same insertion depth. Thereby, the entire portion of the parallel surface 33 of the cover unit 3a is supported by a pair of wedges 4a, thus accomplishing a stable structure. Therefore, the reinforcing bar coupler allows the reinforcing bars 1 and la to be firmly coupled to each other, regardless of the shape of the latitudinal ribs 12 of the reinforcing bars 1 and la.

Meanwhile, the conventional reinforcing bar coupler may have the following problem. That is, the slant surfaces 23 of the sleeve 2a are inclined so that a diameter of the interior of the sleeve 2a is increased from a central portion to both ends of the sleeve 2a. The outer surface of the cover unit 3a is formed so that the cover unit 3a is high at a center thereof and descends from the center to both ends of the cover unit 3a. Further, the length of the cover unit 3a is equal to that of the sleeve 2a. Each wedge 4a is formed to be upwardly inclined from a sharp first end to a second end of the wedge 4a. In such a state, the reinforcing bars 1 and la are respectively inserted through the inlets provided on the both ends of the sleeve 2a so that an end of each reinforcing bar 1, la reaches the central depression 27. Thereafter, the cover unit 3a is inserted into the sleeve 2a through one of the inlets of the sleeve 2a to cover the reinforcing bars 1 and la. At this time, a position of the cover unit 3a is adjusted so that the latitudinal ribs 12 of the reinforcing bars 1 and la are inserted into the corresponding rib insert grooves 32. However, any end of the cover unit 3a may be retracted into the sleeve 2a, according to a position of the latitudinal ribs 12 of the reinforcing bars 1 and la. In this case, both ends of the sleeve 2a do not correspond to both ends of the cover unit 3a, so that the depth of a space between the slant surface 23 of the sleeve 2a and the slant surface of the cover unit 3a may be reduced. At this time, each wedge 4a is not sufficiently fitted into the sleeve 2a, thus leading to undesirable bar coupling. The operation and assembling sequence of the reinforcing bar coupler of the second embodiment are similar to those of the reinforcing bar coupler of the first embodiment, except that the reinforcing bar coupler of the second embodiment includes a pair of wedges 4a. Thus, according to the second embodiment, a pair of wedges 4a are fitted into the gaps defined between the slant surfaces 23 provided on both sides of the sleeve 2a and the parallel surface 33 of the cover unit 3a. At this time, the cover unit 3a strongly compresses the outer surfaces of the reinforcing bars 1 and la, thus accomplishing firm bar coupling. Industrial Applicability

As described above, the present invention provides a reinforcing bar coupler, which includes a sleeve, a cover unit, and a wedge, and which is constructed to receive and couple reinforcing bars, regardless of a shape of latitudinal ribs of the reinforcing bars, thus having excellent compatibility, and accomplishing uniform and perfect coupling regardless of workers . The concrete operational effects of the reinforcing bar coupler according to the present invention are as follows.

The reinforcing bar coupler is capable of coupling two reinforcing bars having latitudinal ribs of the same shape, if only the reinforcing bars have the latitudinal ribs of the same shape regardless of whether the latitudinal ribs of the reinforcing bars have a circular or semicircular shape. A central depression is provided at a center of each of facing surfaces of a sleeve and a cover unit so that the inner diameter of each of the central depressions of the sleeve and the cover unit is larger than the outer diameter of the latitudinal ribs of each reinforcing bar, thus allowing the reinforcing bars to be received in the sleeve and coupled to each other without an additional process of finishing leading ends of the reinforcing bars, although the leading ends of the reinforcing bars are undesirably bent or projected. The wedge of the reinforcing bar coupler, which wedges the cover unit, comprises a single wedge having a length similar to the cover unit, thus being convenient to couple the reinforcing bars to each other.

In the reinforcing bar coupler of the present invention, a plurality of grooves are provided on both surfaces of the wedge, thus reducing friction between the wedge and the sleeve, therefore allowing the wedge to be easily fitted into the sleeve, and accomplishing firm bar coupling. Further, a scale rule is provided on a predetermined portion of the wedge so that the wedge is inserted into the sleeve by a predetermined reference depth, thus allowing firmly and evenly coupled reinforcing bars to be obtained, in addition to ensuring an easy post- inspection.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. A reinforcing bar coupler, comprising: a cylindrical sleeve having a sectional area enough to receive first and second reinforcing bars with a predetermined clearance, the first and second reinforcing bars being axially inserted into the sleeve through inlets provided on first and second ends of the sleeve, the sleeve comprising: a first bar seating part having a semicircular cross-section, the first and second reinforcing bars being seated on the first bar seating part; a plurality of first rib insert grooves provided on the first bar seating part so that latitudinal ribs of the first and second reinforcing bars are inserted into the corresponding first rib insert grooves; and a first slant surface provided on an inner surface of the sleeve to face the first bar seating part, the first slant surface being inclined at a predetermined inclination angle so that a diameter of an interior of the sleeve is increased in a direction from the first end to the second end of the sleeve; a cover unit introduced into the clearance of the sleeve, and having a length longer than the sleeve by a half of a pitch between adjacent latitudinal ribs of the first and second reinforcing bars, the cover unit comprising: a second bar seating part provided on an inner surface of the cover unit so that the first and second reinforcing bars are seated on the second bar seating part; and a plurality of second rib insert grooves provided on the second bar seating part so that the latitudinal ribs of the first and second reinforcing bars are inserted into the corresponding second rib insert grooves, the second rib insert grooves being additionally provided on both edges of the second bar seating part; and a^' first parallel surface provided on an outer surface of the cover unit without being inclined; and a wedge fitted into a gap between the cover unit and the inner surface of the sleeve to wedge the cover unit, and having a length similar to the cover unit, the wedge comprising: a second parallel surface provided at a position contacting the first parallel surface of the cover unit; and a second slant surface provided at a position contacting the first slant surface of the sleeve to be inclined at a first end to a second end of the wedge.

2. The reinforcing bar coupler according to claim 1, comprising: two first slant surfaces provided on the inner surface of the sleeve to face the first bar seating part, the two first slant surfaces being inclined so that a diameter of the interior of the sleeve is increased from a center to the first and second ends of the sleeve; and a pair of wedges fitted into the sleeve through the inlets provided on the first and second ends of the sleeve, each of the pair of wedges having a length to correspond to about a half of a length of the sleeve, and comprising: a second slant surface provided on a surface of each of the wedges to correspond to each of the first slant surfaces of the sleeve; and a second parallel surface provided at a position opposite to the second slant surface to contact the first parallel surface of the cover unit.

3. The reinforcing bar coupler according to claim 1 or 2, further comprising: a scale rule provided on an outer surface of the wedge to have a regular scale interval, thus allowing the wedge to be inserted into the sleeve by a predetermined reference depth.

4. The reinforcing bar coupler according to claim 1 or 2, further comprising: a first central depression provided at a center of the first bar seating part of the sleeve, the first central depression being deeper and wider than each of the first rib insert grooves; and a second central depression provided at a center of the second bar seating part of the cover unit, the second central depression being deeper and wider than each of the second rib insert grooves.

5. The reinforcing bar coupler according to claim 1 or 2, wherein the sleeve comprises: a plurality longitudinal ribs provided on an outer surface of the sleeve to correspond to the longitudinal ribs of the first and second reinforcing bars; and a plurality latitudinal ribs provided on the outer surface of the sleeve to correspond to the latitudinal ribs of the first and second reinforcing bars.

6. The reinforcing bar coupler according to claim 1 or 2, further comprising: a first serrated part provided on at least one of the second parallel surface and the second slant surface of the wedge; and a second serrated part provided on at least one of the first parallel surface of the cover unit and the first slant surface of the sleeve to contact the first serrated part of the wedge.

7. The reinforcing bar coupler according to claim 1 or 2, further comprising: a plurality of grooves axially provided along at least one of the second slant surface and the second parallel surface of the wedge.