Patent ID: 7287303

Claim:
An unidirectional locking device, comprising a base and a lid, and interiorly provided with a roller and an axle base onto which a control knob is screwed, wherein, the base is interiorly provided with a first recession having a hole and a second recession having a positioning hole; a rear end of the base has an inlet notch and an outlet notch, both of which go through to the second recession, while a front end of the base has a protrusion having a central post; the lid is interiorly provided with a first recession having a hole and a second recession having a through hole within a protruding cylinder; a locking hook is provided beside the cylinder; a rear end of the lid has an inlet notch and an outlet notch, both of which go through to the second recession; the roller has a central hole, through which a central post passes, such that the central post can be positioned between the base and the hole of the first recession on the lid; the axle base is provided with a barrier at each of two sides, and a screw hole on a top, which goes out of the through hole of the cylinder on the lid; by way of a screw going through the control knob, the axle base can be combined and fastened to the control knob; the control knob is provided with an axle hole and a locking groove on an interior center and a side edge, respectively, and a spring inside, such that one end of the spring can lock with the locking groove, and that the spring can be held on the top of the axle base by the screw going through the control knob; and the lid is mounted on the base and integrally combined with the base via screws; the rope enters an entrance on a bottom of the locking device, passes by one barrier at the axle base, goes around the roller, and then passes by the other barrier, and finally goes out of an exit.