Cable tensioner and window lifting device having the same

A cable tensioner, comprising:

• a regulating stick, comprising a first abutting portion and a ratchet rack, the ratchet rack comprising a plurality of ratcheting notches, and each of the ratcheting notches comprising a stopping surface and a slope disposed therein and opposite to each other;
• a tube assembly, sleeving the regulating stick and comprising an outer cylinder and an inner cylinder disposed in the outer cylinder, a second abutting portion arranged on an external surface of the outer cylinder, a pawl arranged on the outer cylinder, the pawl comprising an elastic arm and a hook portion arranged on the elastic arm, the hook portion comprising a stopping side, the stopping side abutting against the stopping surface, and the hook portion snap-fitting one of the ratcheting notches;
• and
• a spring, sleeving the outer cylinder and clamped between the first abutting portion and the second abutting portion and preloaded,
• wherein the hook portion snap-fitting on the slope of one of the ratcheting notches is moved to snap-fit on the stopping surface of another of the ratcheting notches via the stopping side when the regulating stick is out stretched from the tube assembly, and the inner cylinder comprises an end abutting against a side of the hook portion opposite to the stopping side;
• wherein the regulating stick comprises a holding slot extended along a circumferential direction of the regulating stick, and the outer cylinder comprises a tenon for snap-fitting into the holding slot to fix the regulating stick and the tube assembly along a longitudinal direction of the tube assembly;
• wherein the holding slot comprises an opening, and the regulating stick and the tube assembly are relatively movable when the tenon leaves the holding slot through the opening;
• wherein the opening comprises an opening direction disposed along a longitudinal direction of the regulating stick.