Pliers with adjustable jaw span

Pliers with adjustable jaw span, comprising a first member and a second member which cooperate with each other, a long slot is formed in the first member, and the second member is connected with the first member by means of a pivot passing through the long slot and rotatable around the pivot relative to the first member, the span of the jaws is adjustable by varying the position of the pivot in the long slot, wherein the edge of the long slot is provided with a number of ratchet teeth, and the pivot is engaged with the ratchet teeth by a pawl, thus the pivot is movable in a first direction and immovable in a second direction which is opposite to the first direction within the long slot, wherein the pawl is disengaged from the ratchet teeth by an external force, so that the pivot is movable in the second direction within the long slot, wherein the pliers further comprises a return spring, which enables the pawl to automatically return to the state in which the pawl is engaged with the ratchet teeth after the external force is eliminated, wherein the pliers further comprises an offset spring, which applies a torque force to the pawl so as to keep a stable engagement between the pawl and the ratchet teeth, wherein the return spring and the offset spring are provided by a single coil spring.