One-way rotation locking device

The invention relates to a one-way rotation locking device, in particular to the one-way rotation locking device used in an oil well casing. The one-way rotation locking device is composed of a body, a friction assembly, locking blocks, a garter spring, a force transmission sleeve and a center pipe. A circumferential guide groove is formed in one end of the body, the continuously-distributed locking blocks are arranged in the guide groove, the locking blocks are bound to the bottom of the guide groove through the garter spring, the locking block at the tail end and the guide groove are welded together, or the guide groove is a non-through groove, the locking block at the tail end cannot rotate anticlockwise, the force transmission sleeve and the body are coaxially arranged, a shifting fork interacting with the locking blocks is arranged at one end of the force transmission sleeve, the garter spring always applies radial tightening force to the locking blocks, and when the force transmission sleeve does not act on the locking blocks, the locking blocks can shrink to the bottom of the guide groove under the effect of the garter spring. When the force transmission sleeve rotates anticlockwise, the locking blocks are pushed to radially move and to be meshed with the inner wall of the casing, the force transmission sleeve cannot rotate, and then therefore the one-way locking function is achieved. The one-way rotation locking device is simple in structure, reliable in performance, good in machining technique, and capable of being widely applied to down-hole tools needing one-way locking.