Pivoted jaw pipe wrench of the three-arm lever type

In a pipe wrench having a generally flat, hollow, narrow body provided with a slot-like open front and rear ends, a fixed jaw arm projecting forwardly from said body and carrying a pivoted, tooth-equipped jaw element at its outer end, a second and movable jaw arm disposed in opposed and spaced relation with the fixed jaw arm, having its inner end region projecting into the body through the slot-like open front end thereof, and carrying a pivoted, tooth-equipped jaw element at its outer end, said second jaw arm being capable of limited longitudinal sliding movement through said open front end, a turnbuckle-type adjusting screw extending between the medial portions of said jaw arms, pivotally connected to the latter, and adapted upon manipulation thereof to effect movement of the second and movable jaw arm toward and away from the fixed jaw arm in order to regulate the pipe-receiving distance between said jaw elements, an operating wrench handle having its forward end projecting into said wrench body through ther slot-like open rear end of the latter and pivotally connected to the body at a point inwardly of its rear end, and a spider-like three-arm lever disposed within said wrench body and having a first lever arm pivoted to the body, a second lever arm designed for camming engagement with the forward end of the wrench handle, and a third and lateral lever arm pivoted to the inner end region of the second and movable jaw arm, the improvement which comprises having the pivoted jaw element at the outer end of the second and movable jaw arm be of a composite nature and embody a case-hardened jaw block provided with pipe-gripping teeth thereon, and a pair of upstanding side plates secured to the opposite sides of such jaw block by roll pins, said case-hardened jaw block being formed with a pair of lateral recesses on opposite sides thereof for reception of the lower edges of said upstanding side plates, and providing the wrench additionally with an anchor pin projecting across said side plates, a limit stop bracket pivoted at its rear end to the wrench body and having forwardly extending abutment arms projecting between said anchor pin and the jaw block, a second anchor pin on said limit stop bracket, and a tension spring connected between said anchor pins and serving rotationally and yieldingly to bias the composite tooth-equipped jaw element into tooth-seating relationship upon a pipe undergoing turning movement by said pipe wrench, said lateral lever arm of the three-arm lever being responsive to swinging movement of the wrench handle in one direction to shift the second and movable jaw arm forwardly through the slot-like open front end of the wrench body and also to effect tilting of such slidable jaw arm in a direction to move the tooth-equipped jaw elements toward each other in pipe-gripping relationship, said three-arm lever having associated with its spring means disposed within said wrench body, positioned between the spider-like three-arm lever and the wrench body and effective to urge the former in a direction yieldingly to bias the wrench handle for reverse swinging movement.