Coupler for connecting reinforcing bars

A coupler for connecting reinforcing bar, comprising:

• a socket with threads formed on an outer circumferential surface thereof;
• a coupler body screw-coupled to each of upper and lower sides of the socket, the coupler body comprising an inlet formed at one end thereof to allow a reinforcing bar to be inserted thereinto, and a hollow portion provided with an inclined surface having an inner diameter gradually decreasing toward the inlet from a side opposite to the inlet, wherein the inclined surface comprises a first inclined surface formed under the inlet and a second inclined surface extending downward from the first inclined surface, wherein the first inclined surface is formed to have a slope causing the inner diameter to reduce more rapidly than the inner diameter of the second inclined surface to enhance coupling;
• a plurality of pieces arranged inside the hollow portion of the coupler body with an outer side surface thereof contacting the inclined surface, the plurality of pieces having a locking protrusion formed on an inner side surface thereof to press-contact the inserted reinforcing bar;
• a piece guide inserted through one end of the plurality of pieces and having a plurality of spacing maintenance portions formed on an outer surface thereof and inserted into a gap between the pieces to widen the gap between the pieces, the piece guide being provided with a magnet to maintain an assembled shape of the pieces seated by the spacing maintenance portions;
• and
• an elastic member arranged inside the hollow portion of the coupler body to press the pieces toward the inlet of the coupler body,
• wherein, when the reinforcing bar inserted through the inlet of the coupler body pushes one end of the piece guide to separate the piece guide from the one end of the plurality of pieces, the pieces are moved toward the inlet along the inclined surface of the coupler body by pressing force of the elastic member and retracted to cause the locking protrusions of the pieces to press-contact an outer surface of the reinforcing bar.