The invention relates to a tool including a pair of jaws (3) interacting with one another by means of actuating means comprising a central stationary portion and two cam plates (4) arranged such that said plates are facing both sides of the central stationary part, which are slidable on said central stationary part. The two cam plates being associated with a shaft for driving linear movement, the jaws being coupled to the central stationary part and the two cam plates (4). Thus, during a forward movement of the cam plates, said plates cause a linear movement away from one jaw respective to the other, during a backward movement thereof, said cam plates (4) cause a linear movement for moving one of the jaws (3) closer to the other.