WO2005100714A1

WO2005100714A1 - Reinforcing bar coupler

Info

Publication number: WO2005100714A1
Application number: PCT/KR2005/001086
Authority: WO
Inventors: Yong Keun Kim
Original assignee: Yong Keun Kim
Priority date: 2004-04-16
Filing date: 2005-04-14
Publication date: 2005-10-27
Also published as: KR101112313B1; KR20050100839A

Abstract

A sliding type reinforcing bar coupling is provided for simply and firmly bonding a pair of butted reinforcing bars. This device comprises a pair of first segments having semi-cylindrical outer shape with an arch-shape inner base portion to mate with a pair of butted reinforcing bars and a pair of right triangle-shaped sliding edge portions with declined surfaces. A pair of sliding segments has a long trapezoidal bar-shaped flat portion, a dovetailed groove portion along both ends with inwardly declined surfaces for slide-fitting to the right triangle-shaped sliding edge portions of the first segments. The pair of the first segments is overlapped on the pair of butted reinforcing bars. Then, the dovetailed groove portion of the sliding segments is slid into the right triangle-shaped sliding edge portions of the first segments for tightly bonding the pair of butted reinforcing bars.

Description

Description REINFORCING BAR COUPLER Technical Field

[1] The present invention relates to a sliding type reinforcing bar coupling, and more particularly, to a mechanical butt-joint type of coupling used to bond a pair of reinforcing bar ends in order to reinforce the concrete structure without deteriorating the properties of the reinforcing bar. The device consists of a pair of first segments, a pair of sliding segments and a wedge for firmly bonding the reinforcing bars. Background Art

[2] Even though a concrete structure has good durability against a compression load, it is very weak against a tensile load. In order to resolve this problem, reinforcing bars are incorporated into the concrete structure.

[3] Generally, the reinforcing bars are produced to a certain length at the factories for easy handling and transporting. Due to the fixed length, most reinforcing bars are coupled to meet the required length at the building site. Therefore, it is essential to prepare a good bonding device for practically reinforcing the concrete structure.

[4] The conventional methods for bonding the reinforcing bars include overlap bonding, gas welding, threaded coupling and mechanical butt-joint coupling.

[5] To this day, the overlap-bonding method is predominantly used. The process is to overlap the proximal ends of the reinforcing bars by a certain length and tie the overlapped portion of the reinforcing bars with binding wires. However, the overlap- bonding method has a disadvantage: because the overlap-bonding simply relies on the concrete adhesion, it will be easily weakened and lose bonding force when the reinforcing bars get rusty or the concrete near the joint expands and cracks. This may cause the concrete structure to collapse.

[6] The process of gas welding, which uses oxygen-acetylene gases, is to align the ends of the two reinforcing bars and weld the butted ends of the reinforcing bars with a high temperature flame. It also has a disadvantage that the welded portion of the reinforcing bars is weakened due to the high temperature applied and, after welding, the welded portion must be inspected using a specialized technique such as an ultrasonic test.

[7] The threaded coupling process is to form a set of left and right external threads on the proximal end of each reinforcing bar and affix a coupling that has been formed with a set of left and right internal threads. The threaded coupling method also has a disadvantage that it is inconvenient and inefficient to form the threads in the restricted space of the construction site. Because the diameter of the reinforcing bars is reduced when the ends are threaded, it also weakens the strength of the reinforcing bars. Furthermore, the threaded coupling requires a turning tool such as a spanner for fastening the sleeves onto the reinforcing bars. Due to densely arranged reinforcing bars, it may be difficult to turn the fastening tool in a narrow working area.

[8] The parts assembly type coupling is designed to firmly bond the raised ribs of the reinforcing bars using specially designed components. A pair of butted reinforcing bars is overlapped with the special shaped segments; simultaneously the ridges and grooves of the segment are properly fitted into the ribs of the reinforcing bars.

[9] Especially, the U. S. Patent No. 6,860,672 (title: reinforcing bar coupling owned by the same applicant of this patent application), comprising a cylindrical sleeve, an intermediate pad, and a pair of wedges, has a simple configuration to easily and promptly perform the coupling operations at the construction site. The process of joining a pair of butted reinforcing bars using a reinforcing bar coupling is as follows: The end of one reinforcing bar is inserted into a cylindrical sleeve through one end opening, and the end of the other reinforcing bar is inserted into the cylindrical sleeve through the opposite end opening. At this point, the ribs of the reinforcing bars are properly fitted into the annular grooves of the cylindrical sleeve. Next, an intermediate pad is inserted into the cylindrical sleeve. At this point, it must be ensured that the ribs of the reinforcing bars are properly mounted into the annular grooves of the intermediate pad. Then, a pair of wedges is inserted into a gap between the cylindrical sleeve and the intermediate pad through each end opening, and finally the wedges are driven in with a pressing tool or a hammer.

[10] Because of employing a wedge-tightening method, it has the merit of easily and promptly coupling the pair of butted reinforcing bars. It also maintains the same stable tensile strength and rigidity as the reinforcing bar itself, because the cylindrical sleeve is produced from cast metal.

[11] Even though this reinforcing bar coupling has the aforementioned merits, it still has a disadvantage of high production costs and brittleness. Because the sleeve has a cylindrical shape, the casting process is suitable. However, cast parts can be brittle, but on the other hand, if produced through the preferable multi-stage manufacturing process, such as hot-rolling or forging and welding, the production cost is expensive. It also has the disadvantage of the inconvenient assembly process. Disclosure of Invention Technical Problem

[12] The purpose of the present invention is to provide a simpler configuration of the reinforcing bar coupling for more easily and promptly performing the coupling operation and reducing the production cost as compared to the reinforcing bar coupling that is disclosed in the U. S. Patent No. 6,860,672. Technical Solution

[13] In order to accomplish the above objectives, the present invention provides a slide- fitting type of reinforcing bar coupling comprising: a pair of first segments having a semi-cylindrical outer shape with an arch-shape inner base portion to mate with a pair of butted reinforcing bars and a pair of right triangle-shaped sliding edge portions with declined surfaces. A pair of sliding segments has a long trapezoidal bar-shaped flat portion and a dovetailed groove portion along both ends with inwardly declined surfaces for slide-fitting to the right triangle-shaped sliding edge portions of the first segments.

[14] The bonding process of the slide-fitting type reinforcing bar coupling is as follows: A pair of the first segments are overlapped on a pair of butted reinforcing bars and, by locating both ends of the reinforcing bars to simultaneously rest in the central hollow, the circumferential ridges and annular grooves of the first segments are properly fitted into the semi-annular ribs of the butted reinforcing bars. Next, a pair of the sliding segments having a trapezoidal flat bar-shaped portion is inserted into the right triangle- shaped sliding edge portions of the first segments. At this time, the wider width of the dovetailed groove portion of the sliding segments is inserted into the narrower width of the right triangle-shaped sliding edge portions of the first segments until both sliding segments are tightly fitted. Then, both sides of the striking heads are struck until the sliding segments are firmly bonding the pair of butted reinforcing bars. The insertion depth is measured by the scale until it reaches the pre-set position.

[15] Finally, a wedge is transversely inserted between the butted reinforcing bars by passing it through the slot. The wedge exerts expanding forces against the reinforcing bars opposite to the longitudinal directions. Then, the first segments and sliding segments are firmly bonding the pair of butted reinforcing bars and can support tensile forces. Advantageous Effects

[16] The slide-fitting type of the present invention has a simpler configuration than the cylindrical sleeve type of reinforcing bar coupling. Thus, it is possible to perform the coupling operation faster and more easily than with the cylindrical sleeve type.

[17] It has a merit of having the same stable strength as the reinforcing bar, because the slide-fitting type coupling is produced by a hot-rolling, forging process without welding. It also has a merit of reducing the production cost via mass production due to the simple configuration.

[18] It has an effect to enhance concrete structures because a pair of first segments and sliding segments of the slide-fitting type reinforcing bar coupling provide firm bonding of a pair of butted reinforcing bars. Brief Description of the Drawings

[19] Fig. 1 shows an exploded perspective view of the slide-fitting type reinforcing bar coupling of the present invention.

[20] Fig. 2 is a front view showing the first segments mating with a pair of reinforcing bars of the present invention.

[21] Fig. 3 is a front view showing the sliding segments of the present invention, with slots for the wedges.

[22] Fig. 4 is a cross-sectional view along an axis showing the slide-fitting type reinforcing bar coupling with the evenly arranged ribs of the reinforcing bars.

[23] Fig. 5 is a cross-sectional view along an axis showing the slide-fitting type reinforcing bar coupling with the unevenly arranged ribs of the reinforcing bars.

[24] Fig. 6 is a cross-sectional front view of the assembled first and sliding segments of the present invention.

[25] Fig. 7 is a perspective view showing the final assembly of the slide-fitting type reinforcing bar coupling of the present invention. Best Mode for Carrying Out the Invention

[26] Hereinafter, a slide-fitting type reinforcing bar coupling of the present invention will be described in great detail with reference to the accompanying drawings.

[27] As shown in Figs. 1 through 7, a slide-fitting type reinforcing bar coupling of the present invention is disclosed for firmly bonding the butted reinforcing bars (1, la) by using a pair of first segments (2) and sliding segments (3).

[28] A sliding type reinforcing bar coupling comprises a pair of first segments (2) formed with a semi-cylindrical outer shape and an arch-shape inner base portion. The first segments (2) have a sufficient length to overlap several ribs (12) of the reinforcing bar and sufficient width (inner diameter) to envelop the circumferences of the butted reinforcing bars (1, la). The inner base portions of the first segments (2) also are formed with a plurality of circumferential ridges (21) and annular grooves (22) for fitting with the ribs (12) of reinforcing bars (1, la). At the centers of the arch-shaped inner surfaces of the first segments (2), a central hollow (23) having wider width and slightly deeper depth than the annular grooves (22) is provided for mounting the ends of the reinforcing bars (1, la). Thus, the burrs that might be generated at the ends of the reinforcing bars (1, la) during cutting can be rested in the central hollow (23).

[29] The outer surface of the first segment (2) is formed with a plurality of semi-annular ribs (26) and semi-longitudinal ribs (25) for improving adhesion to the concrete, which are similar to the ribs (12) and seams (11) disposed on the outer surface of the reinforcing bars (1, la). An outer central reinforcing portion (28) is also provided at the outer center of the first segment (2) for enhancing the weakened portion of the central hollow (23), which is cut out wider in width and slightly deeper in depth than the annular grooves (22) in the inner surface.

[30] The first segment (2) has integrally formed a pair of right triangle-shaped sliding edges (24) with inwardly declined surfaces (24a) along the entire length of both edges for locking.

[31] A pair of the sliding segments (3) is formed with a long trapezoidal bar-shaped flat portion (31)and a dovetailed groove portion (32) along both ends with inwardly declined surfaces (32a) for slide-fitting into the right triangle-shaped sliding edges (24) of the first segments (2). The declined surfaces (32a) of the dovetailed groove portion (32) have the same angle of declination as the declined surfaces (24a) of the first segments (2).

[32] The first segment (2) is formed with a set of first serrations (27) at one end of the declined surfaces (24a) of the right triangle-shaped sliding edges (24). The pair of sliding segments (3) is formed with a set of sliding serrations (37) at one end of the declined surfaces (32a) of the dovetailed groove portion (32). The first and sliding serrations (27, 37) are engaged and interlocked with each other. Once the first and sliding serrations are engaged, the sliding segments will not slip out in the opposite direction.

[33] As shown in Figs. 4 and 5, the reinforcing bar (1, la) is generally formed with the semi-annular ribs (12) and longitudinal lateral seams (11) on its outer surface. Most reinforcing bars (1, la) have the semi-annular ribs (12) arranged symmetrically with respect to the longitudinal lateral seams (11). Some reinforcing bars (1, la) have the semi-annular ribs (12) arranged unevenly with respect to the longitudinal lateral seams (11). However, the first segments (2) of the present invention have been designed to effectively envelop the various arrangements of the ribs (12) of the reinforcing bars (1, la). The semi-annular ribs (12) and longitudinal lateral seams (11) formed on the reinforcing bars (1, la) are fitted into the circumferential ridges (21) and annular grooves (22) of the first segments (2). In order to stably envelop the butted reinforcing bars (1, la) which have various patterns of rib (12) arrangement, the first segment (2) having the circumferential grooves (22) and the central hollow (23) must have enough tolerance and intervals. Therefore, the arch-shape inner base of the first segment (2) is divided into a long and a short side with respect to the central hollow (23). The long side is longer than the short side by one-half the width of a circumferential groove (22).

[34] Such first segments (2) will properly fasten the butted reinforcing bars (1, la) by fitting the ribs to the circumferential groove (22) and resting the ends of the butted reinforcing bars (1, la) in the central hollow (23). [35] A pair of sliding segments (3) is formed with a trapezoidal flat bar-shaped portion (31) and dovetailed groove portions (32) with inwardly declined surfaces (32a) at both ends along the longitudinal axis. A width of the flat bar-shaped portion (31) is wide enough to slide-fit into the right triangle-shaped sliding edges (24) when the pair of the first segments (2) is firmly assembled with the butted reinforcing bars (1, la). The overall appearance of the sliding segments (3) is similar to a long trapezoidal flat bar, in which the width is gradually increasing along the longitudinal axis, for fitting tightly into the right triangle-shaped sliding edges (24) of the first segments (2) as it is inserted. In other words, the clearance between the dovetailed groove portions (32) of the sliding segments (3) is the same as or slightly wider than the distance between the right triangle-shaped sliding edge portions (24) when the first segments (2) firmly envelop the butted reinforcing bars (1, la). The declined surfaces (32a) of the sliding segments (3) have the same slope for mating with the declined surfaces (24a) of the first segments (2). On one end of the declined surfaces (24a) of the first segments (2) is formed a set of first serrations (27). The pair of sliding segments (3) is formed with a set of sliding serrations (37) on one end of the declined surfaces (32a) of the dovetailed groove portion (32). The first serrations (27) and sliding serrations (37) are engaged with each other for locking. Once the first serration is engaged to the sliding serration, it will not slip out in the opposite direction. A threaded hole (36) and a sharp point bolt (5) are provided on the long trapezoidal flat bar-shaped portion (31) for fastening the reinforcing bars (1, la).

[36] A striking head (35) is also provided on the narrow side of the long trapezoidal flat bar-shaped portion (31) of the sliding segments (3). This striking head (35) is a convenient way to perform the insertion while the sliding segments (3) are forcibly inserted into the first segments (2) without damaging the reinforcing bars (1, la).

[37] A cutout slot (34) is provided in the center of the flat bar-shaped portion (31) to reduce weight and save material. Passing through this slot (34), a wedge (4) is transversely inserted between the butted ends of the reinforcing bars (1, la). Then, the wedge (4) exerts pushing forces to the butted ends of the reinforcing bars (1, la) opposite to the longitudinal directions. Thus, the contacting surfaces between the circumferential groove (22) of the first segments (2) and the semi-annular ribs (12) of the reinforcing bars (1, la) are tightly bonded. As a result, there is no slippage in the axial direction of the reinforcing bar coupling.

[38] Both lateral surfaces of the wedge (4) that contact the butted pair of the reinforcing bars (1, la) are also formed with serrations (41).

[39] A scale (33) is provided on the striking head (35) side of the top edge-surface of the dovetailed groove portion (32) for controlling uniform insertion depth of the sliding segments (3) into the first segments (2). At the construction site, this scale helps the workers to perform the uniform bonding by measuring the insertion depth with constant striking strength on the assembly of the same sized reinforcing bars (1, la). For example, the insertion depth and striking strength are measured and recorded during the initial performances for a specific size of the reinforcing bars (1, la). The optimum insertion depth and strength can be determined as a standard for the specific size of the reinforcing bars (1, la). Then, the rest of the bonding job can be performed by adopting the standard insertion depth with strength. It is also convenient and easy to inspect the results of the bonding job.

[40] As shown in Fig. 5, the first segments (2) envelop a pair of reinforcing bars (1, la), which have semi-annular ribs (12) arranged unevenly with respect to the longitudinal lateral seams (11). Regardless of the rib (12) arrangement patterns of the reinforcing bars (1, la), the first segments (2) of the present invention are able to effectively overlap the reinforcing bars (1, la). Due to the same intervals and clearance, the circumferential ridges (21) and annular grooves (22) of the first segments (2) are properly fitted into the semi-annular ribs (12) of the reinforcing bars (1, la). The first segments (2) provide the central hollow (23) as a clearance that is for not only resting the ends of the butted reinforcing bars (1, la), but also stably overlapping the various rib (12) arrangements of reinforcing bars (1, la). Thus, the overall length of the first segment (2) must include an optimum clearance for overlapping the various rib (12) arrangement patterns of reinforcing bars (1, la). The first segments (2) consist of an upper first segment and a lower first segment. The upper first segment is formed symmetrically with respect to the central hollow (23) having three circumferential grooves (22) on each side. The lower first segment (2) is divided into a longer side and a shorter side with respect to the central hollow (23). The shorter side has three circumferential grooves (22). The longer side has three and half of the circumferential grooves (22), and is longer than the shorter side by one-half width of the circumferential groove (22). In such a configuration, the first segments (2) are able to stably and firmly overlap the unevenly arranged ribs of the reinforcing bars (1, la). As shown in the final assembly, one end of the upper and lower first segments (2) are matched evenly, but the opposite ends are uneven.

[41] The trapezoidal flat bar-shaped portion (31) of the sliding segments (3) is tapered along the longitudinal direction. The right triangle-shaped sliding edges (24) of the first segments (2) are also tapered with the same slope as the trapezoidal flat bar- shaped portion (31) of the sliding segments (3) along the longitudinal direction. Therefore, the tolerance due to the slightly different diameters of the reinforcing bars (1, la) will be compensated by the different insertion depth of the sliding segments (3).

[42] Hereinafter, the assembly process of the slide-fitting type reinforcing bar coupling of the present invention will be described in detail as follows: [43] First, an upper first segment (2) is overlapped on a pair of butted reinforcing bars, resting both ends of the reinforcing bars in the central hollow (23) while simultaneously fitting the circumferential ridges (21) and annular grooves (22) of the upper first segment (2) into the semi-annular ribs (12) of the reinforcing bars (1, la). A lower first segment (2) is enveloped over the pair of butted reinforcing bars, resting both ends of the reinforcing bars in the central hollow (23). At the same time, the circumferential ridges (21) and annular grooves (22) of the lower first segment (2) are properly fitted into the semi-annular ribs (12) of the reinforcing bars (1, la).

[44] Next, a pair of the sliding segments (3) having a trapezoidal flat bar-shaped portion is slide-inserted into the right triangle-shaped sliding edge portions of the first segments (2). At this time, the wider width of the dovetailed groove portion (32) of the sliding segments (3) is inserted into the narrower width of the right triangle-shaped sliding edge portions (24) of the first segments (2) until both sliding segments (3) are tightly fitted.

[45] Then, both sides of the striking heads (35) are struck until the sliding segments (3) are firmly bonding the pair of butted reinforcing bars. The insertion depth is measured by the scale (33) until it reaches the pre-set position.

[46] Finally, a wedge (4) is transversely inserted between the butted reinforcing bars (1, la) by passing through the slot (34). The wedge (4) exerts expanding forces against the reinforcing bars (1, la) opposite to the longitudinal direction. Then, the first segments (2) and sliding segments (3) are firmly bonding the pair of butted reinforcing bars (1, la) without slippage when subject to a tensile force.

[47] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. Industrial Applicability

[48] As discussed above, the sliding type reinforcing bar coupling of the present invention comprises a pair of first segments, sliding segments and a wedge, without using a sleeve.

[49] Because the present coupling structure does not use the sleeve, it has an advantage of reducing the production cost and allowing mass production by the prime process of casting or forging without a welding process. So, it is possible to produce and maintain parts of the same quality as the reinforcing bar. [50] It has an advantage of increasing the working efficiency and enhancing the concrete strength, because the present sliding type reinforcing bar coupling has a simple structure and prompt assembly by virtue of slide-fitting of the sliding segments into the first segments.

[51] It has an advantage of allowing a firm and secure bond between reinforcing bars of various sizes by adjusting the insertion depth of the sliding segments into the first segments.

Claims

[1] A sliding type reinforcing bar coupling for firmly bonding a pair of butted reinforcing bars comprising: a pair of first segments (2) having semi-cylindrical outer shape with an arch- shape inner base portion to mate with a pair of reinforcing bars (1, la), and a pair of right triangle-shaped sliding edge portions (24) with declined surfaces (24a) integrally formed along both edges, and a pair of sliding segments (3) having a long trapezoidal bar-shaped flat portion (31), a dovetailed groove portion (32) along both ends with inwardly declined surfaces (32a) for slide-fitting to said right triangle-shaped sliding edge portions (24) of said first segments (2), wherein said declined surfaces (32a) of the dovetailed groove portion (32) have the same declined angle as said declined surfaces (24a) of the first segments (2).

[2] The sliding type reinforcing bar coupling as set forth in claim 1, wherein said first segment (2) further comprises a plurality of circumferential ridges (21) and annular grooves (22) on the arch-shape inner base portion for mating with the ribs (12) of butted reinforcing bars (1, la).

[3] The sliding type reinforcing bar coupling as set forth in claim 2, wherein said first segment (2) further comprises a central hollow (23) having wider width and slightly deeper depth than said circumferential grooves (22) on the arch-shape inner base portion.

[4] The sliding type reinforcing bar coupling as set forth in claim 2, wherein said outer surface of the first segment (2) comprises a plurality of semi- annular ribs (26) and semi-longitudinal ribs (25) similar to the ribs disposed on the outer surface of the reinforcing bars (1, la) for improving adhesion to concrete and an outer central reinforcing portion (28) due to the central hollow (23) of the arch-shape inner base portion.

[5] The sliding type reinforcing bar coupling as set forth in claim 1, wherein said pair of the first segments (2) is formed with a set of first serrations (27) on one end of the declined surfaces (24a) of the right triangle-shaped sliding edge portions (24), and said pair of the sliding segments (3) is formed with a set of sliding senations (37) on one end of the declined surfaces (32a) of the dovetailed groove portion (32) for interlocking with each other.

[6] The sliding type reinforcing bar coupling as set forth in claim 1, wherein said circumferential grooves (22) formed on the arch-shape inner base portion of the first segment (2) are divided into a long and a short side with respect to the central hollow (23), and said long side is longer than said short side by one-half of the width of a circumferential groove (22).

[7] The sliding type reinforcing bar coupling as set forth in claim 1, further comprising a striking head (35) on a narrow side of the long trapezoidal bar- shaped flat portion (31) of the sliding segments (3).

[8] The sliding type reinforcing bar coupling as set forth in claim 1, further comprising a threaded hole (36) and a bolt (5) on the long trapezoidal bar-shaped flat portion (31) for press-fastening the reinforcing bars (1, la).

[9] The sliding type reinforcing bar coupling as set forth in claim 1, further comprising a slot (34) in the center of the long trapezoidal bar-shaped flat portion (31) for transversely passing through the reinforcing bar coupling.

[10] The sliding type reinforcing bar coupling as set forth in claim 1, further comprising a wedge (4) having senations (41) on both sides, said wedge (4) being inserted through said slot (34) for transversely passing between the reinforcing bars (1, la).

[11] The sliding type reinforcing bar coupling as set forth in claim 1, further comprising a scale (33) on the top end-surface of the long trapezoidal bar-shaped flat portion (31) to control the insertion depth of the first and sliding segments (3).