In laparoscopic surgery, tying of knots is not easy, as it involves the use of long handled graspers and the necessity to pass one end of the suture ligature around the opposite half of the suture, with release and re-grab of the passing end of the suture. The present invention avoids the “passing with the release and re-grab”, and makes the tying easier, faster and automatic. It conforms to the general size and shape of a standard laparoscopic instrument. The handle is pistol shaped with two control triggers, one for grasping and the other for rotating. The sheath is elongated and tubular, containing two control rods. The tip is bullet shaped, containing three operating mechanisms, one for grasping the leading end of a suture, a second for trapping the opposite half of the same suture, a third for rotating the grasped end of the suture 360 degrees around the trapped portion, thus forming a knot.The trapping mechanism uses an axle with a hollow center and an open-ended side slot. The other members of the rotating and trapping mechanisms have these same features, which allow the suture to enter and exit the hollow center. Grasping is performed by a miniature grasper, which has no handle or shaft, with its entire body contained within a part that rotates, called the rotator. Rotation is generated by a slider-crank mechanism which converts linear motion to rotary motion, and avoids the dead centers with a patented L-shaped connecting rod and deflecting pillars (U.S. Pat. No. 9,194,468). The rotation is then transmitted through two modified spur gears to the rotator, and hence also to the miniature grasper. The rotator represents a short sagittal segment removed from the tip, modified to rotate and to contain the miniature grasper, and then replaced in position. To enable the grasper to rotate, there is an intentional discontinuity in its controlling rod, but control from the handle is maintained by the interposition of a semi-open ball and socket joint in the rod.
