Apparatus of adjustable wrench for securing movable jaw

An adjustable wrench, comprising:

• a handle having a head portion and shank, wherein said head portion has a fixed jaw, a transverse guiding slot and an opening communicated with said guiding slot;
• a movable jaw having a guiding portion and a rack on said guiding portion, wherein said movable jaw receives said guiding portion in said guiding slot of said handle to be moved toward or away from said fixed jaw,
• an adjusting worm having a through hole and a helical tooth, wherein said adjusting worm is received in said opening and engages said helical tooth with said rack of said movable jaw;
• a supporting device made of a flexible material and having at least a part received in said through hole of said adjusting worm to make said adjusting worm can be turned along said supporting device and can be moved along a diameter orientation thereof, and
• a driving device provided on said handle for moving said adjusting worm toward said movable jaw.