Abstract: A locking device for a window or a door, wherein the window or the door has a sash slidable in a horizontal direction within a frame. When a user turns on a switch to control a block to move from the first position to the second position, the block protrudes out of a vertical surface of the sash, thereby driving a linkage member to disengage from the frame. At this time, the user could hold and push the block in the horizontal direction to move the sash between a third position and a fourth position. When the sash is pushed back to the third position, the block could be controlled to move back to the first position, namely back to a mounting groove, thereby moving the linkage member to a position where the linkage member is engaged with the frame. A method of operating thereof is provided as well.

Abstract: A locking device for a window or a door, wherein the window or the door has a sash slidable in a horizontal direction within a frame. When a user turns on a switch to control a block to move from the first position to the second position, the block protrudes out of a vertical surface of the sash, thereby driving a linkage member to disengage from the frame. At this time, the user could hold and push the block in the horizontal direction to move the sash between a third position and a fourth position. When the sash is pushed back to the third position, the block could be controlled to move back to the first position, namely back to a mounting groove, thereby moving the linkage member to a position where the linkage member is engaged with the frame. A method of operating thereof is provided as well.