Abstract: Disclosed herein is an upper housing 100 having openings that are respectively defined in a front surface and a rear surface thereof and in which first and second moving paths 110 and 120 are defined; a first blade 200 installed in the upper housing 100 to move upward from a lower side, thereby opening/closing the first moving path 110; a first shaft 300 coupled to a lower portion of the first blade 200; a lower housing 400 disposed below the upper housing 100, in which a rotation guide groove 410 for guiding rotation of a L-motion block 500 at a fixed position while the first blade 200 moves in a close direction C is defined in each of both inner surfaces of the lower housing (400).

Abstract: Disclosed herein is an upper housing 100 having openings that are respectively defined in a front surface and a rear surface thereof and in which first and second moving paths 110 and 120 are defined; a first blade 200 installed in the upper housing 100 to move upward from a lower side, thereby opening/closing the first moving path 110; a first shaft 300 coupled to a lower portion of the first blade 200; a lower housing 400 disposed below the upper housing 100, in which a rotation guide groove 410 for guiding rotation of a L-motion block 500 at a fixed position while the first blade 200 moves in a close direction C is defined in each of both inner surfaces of the lower housing (400).