Pliers for gripping workpieces of different sizes

A pair of pliers, comprising:

• first and second handle members including first and second non-channeled jaw ends, first and second handle ends and first and second intermediate portions formed between said first and said second jaw ends and said first and said second handle ends respectively, said first intermediate portion of said first handle member including a pair of parallel planar members for slidably receiving said second intermediate portion of said second handle member therebetween, said first intermediate portion of said first handle member including a rack means located closer to said first handle end and including a contact surface means located closer to said first jaw end, said second handle member including a stop means secured on said second jaw end thereof for engaging with said contact surface means and for preventing said second intermediate portion from disengaging from said first intermediate portion;
• spring means for biasing said second jaw end away from said first jaw end;
• a pawl means pivotally secured on said second intermediate portion and including a toothed end for engaging with said rack means and including a contact end for engaging with said rack means and for preventing said toothed end from engaging with said rack means;
• means for biasing said contact end of said pawl means to engage with said rack means;
• two panels pivotally coupled to said first handle end of said first handle member, a plate pivotally coupled to said second handle end of said second handle member and pivotally coupled between said panels at a shaft, said plate including a curved slot having a curvature located at said shaft, each said panel including a protrusion extending therefrom and slidably engaged with the curved slot so as to limit a rotational movement between said panels and said plate, each said panel including a rounded relatively thicker section through which the shaft extends, each said panel further including a stub extending therefrom and facing each other;
• said plate further including a hook portion;
• a torsion spring mounted between the stubs, the torsion spring including a first end attached to the first handle member and a second end attached to the hook portion of the plate;
• said second jaw end being moved away from said first jaw end so as to grip a workpiece of large size, said stop means being caused to engage and to move along said contact surface means when said first and said second handle ends are moved toward each other in order to move said first and said second jaw ends toward each other so as to grip the workpiece, said second handle member being moved relative to said first handle member so as to rotate said pawl means in order to engage with said toothed end with said rack means and so as to secure said first and said second intermediate portions together when said first and said second jaw ends grip the workpiece therebetween.