The current invention aims at improving the playability, durability, and spin generation of different playing rackets, as tennis, squash, and badminton rackets. The method to do so is by applying mechanical forces which generate relative motion of the latitudinal strings over the longitudinal strings. This is done in order to create friction that generate depressions in the contact points of the latitudinal strings with the longitudinal strings. These depressions, made by the described method and machine, induce more friction, and generate spin, while increasing the playability and durability during the play.

The invention is directed toward a string clamp for a tennis racket stringing machine where the string is locked within the clamp between the end of the string clamp which is locked in place and the locking lever. This configuration allows a smaller string clamp to be utilized and also lengthens the life of the string clamp. The string clamp may have shaped feet which fit within channels in a mounting plate in a tennis racket stringing machine. The shaped feet allow the clamp to be removably secured to the mounting plate of the stringing machine when the string clamp is locked.

The invention is directed toward a string clamp for a tennis racket stringing machine where the string is locked within the clamp between the end of the string clamp which is locked in place and the locking lever. This configuration allows a smaller string clamp to be utilized and also lengthens the life of the string clamp. The string clamp may have shaped feet which fit within channels in a mounting plate in a tennis racket stringing machine. The shaped feet allow the clamp to be removably secured to the mounting plate of the stringing machine when the string clamp is locked.

A positioning structure of a clamper of a threading machine for a racket contains: a rack, an engagement protrusion, an operation member, and two springs. A fixing holder is erected on a support plate of the threading machine, and the rack includes multiple first teeth, the fixing holder includes an accommodation chamber with an opening. The engagement protrusion is received in the accommodation chamber and includes a toothed extension on which multiple second teeth are formed. The engagement protrusion further includes a recess and an abutting fence. The operation member includes a drive portion and a push portion. The two springs are mounted on a top of the engagement protrusion, and two ends of each spring abut against the engagement protrusion and the fixing holder respectively so that each spring forces the engagement protrusion to engage with the rack.

A positioning structure of a clamper of a threading machine for a racket contains: a rack, an engagement protrusion, an operation member, and two springs. A fixing holder is erected on a support plate of the threading machine, and the rack includes multiple first teeth, the fixing holder includes an accommodation chamber with an opening. The engagement protrusion is received in the accommodation chamber and includes a toothed extension on which multiple second teeth are formed. The engagement protrusion further includes a recess and an abutting fence. The operation member includes a drive portion and a push portion. The two springs are mounted on a top of the engagement protrusion, and two ends of each spring abut against the engagement protrusion and the fixing holder respectively so that each spring forces the engagement protrusion to engage with the rack.

An automatic racket stringing system includes: two lens modules, respectively shooting a racket thread hole on a racket at a first preset position from different two angles, and the lens modules are based on the angles and determine a first relative coordinate of the racket line hole through a triangulation method; and a control unit controls a robotic arm to grab the racket from an initial position and move the racket to the first preset position; the control unit controls the robotic arm to a second preset position clamps a first end of a racket line, and when the first end of the racket line extends a preset length, it is cut by the robotic arm.

An automatic racket stringing system includes: two lens modules, respectively shooting a racket thread hole on a racket at a first preset position from different two angles, and the lens modules are based on the angles and determine a first relative coordinate of the racket line hole through a triangulation method; and a control unit controls a robotic arm to grab the racket from an initial position and move the racket to the first preset position; the control unit controls the robotic arm to a second preset position clamps a first end of a racket line, and when the first end of the racket line extends a preset length, it is cut by the robotic arm.

A pulling string apparatus of a stringing machine comprising a string gripper, a sensor, a drive element, a transmission mechanism and a control circuit; the sensor is connected with the string gripper to detect the pull force of the string gripper; the control circuit compares the detected pull force value with a pre-set value, and control the rotation of the drive element; the transmission mechanism comprises a mounting base, a sliding block, a transmission rack and a drive gear; wherein the drive gear is connected to the drive element and is engaged with the transmission rack, the sliding block arranged on the transmission rack is connected with the sensor; when the sensor and the string gripper are driven forward or backward by the sliding block under the act of the transmission rack engaged with the drive gear, the racket string will be tensioned or loosened.

A pulling string apparatus of a stringing machine comprising a string gripper, a sensor, a drive element, a transmission mechanism and a control circuit; the sensor is connected with the string gripper to detect the pull force of the string gripper; the control circuit compares the detected pull force value with a pre-set value, and control the rotation of the drive element; the transmission mechanism comprises a mounting base, a sliding block, a transmission rack and a drive gear; wherein the drive gear is connected to the drive element and is engaged with the transmission rack, the sliding block arranged on the transmission rack is connected with the sensor; when the sensor and the string gripper are driven forward or backward by the sliding block under the act of the transmission rack engaged with the drive gear, the racket string will be tensioned or loosened.

An automatic racket stringing system includes: two lens modules, respectively shooting a racket thread hole on a racket at a first preset position from different two angles, and the lens modules are based on the angles and determine a first relative coordinate of the racket line hole through a triangulation method; and a control unit controls a robotic arm to grab the racket from an initial position and move the racket to the first preset position; the control unit controls the robotic arm to a second preset position clamps a first end of a racket line, and when the first end of the racket line extends a preset length, it is cut by the robotic arm.