Adjustable plier wrench hand tool

A method for locking the jaws of pliers together so as to firmly grip an object between them, wherein the pliers comprise a main body, a proximal and a distal end, an upper jaw and a lower jaw located at the distal end, said lower jaw slidably mounted to the main body and capable of moving towards and away from said upper jaw, said lower jaw having a rack with teeth, an adjustment assembly for adjusting the relative position of the upper and lower jaw wherein the adjustment assembly includes a cam with a cam flat surface and a cam surface, a plier handle, said plier handle fastened to the main body by a plier handle hinge pin which extends through the main body and then through the plier handle, the plier handle pivoting about the plier handle hinge pin and having a plier handle head which has a plier handle head flat section and an apex, a thumbscrew which is threaded, said threads mating with the teeth on the lower jaw for moving it with respect to the upper jaw, the adjustment assembly further comprising a stub shaft extending through a bore in the center of the thumbscrew comprising the steps of:

• a) adjusting the relative position of the upper jaw and lower jaw by turning the thumbscrew so that the thumbscrew acts as a worm gear, meshing with the teeth of the rack on the lower jaw, moving the lower jaw toward and away from the upper jaw;
• and
• b) pivoting the plier handle about the plier handle hinge pin, bringing it from an open position where it is relatively perpendicular to the main body to a closed position where it is substantially parallel to the main body, so that the plier handle head flat section fits tightly against the cam flat section, firmly locking the thumbscrew through which the stub shaft extends, and holding the lower jaw in place against the threads of the thumbscrew.