GB689250A - Improvements in pipe wrenches - Google Patents

Abstract

689,250. Wrenches. CRANNER, B. June 26, 1950 [June 27, 1949], No. 15929/50. Class 61 (iii). In a pipe wrench having a fixed jaw carried by a handle arm and a movable jaw having curved surfaces which are slidable on curved surfaces on the arm, the distance between the jaws being adjustable, the coacting curved surfaces have centres of curvature external of the tool, and the movable jaw is adapted to slide upon the curved surfaces on the arm and to be displaced with respect to the fixed jaw when the wrench is operated. The fixed jaw 11 is carried by a lever arm 3 which is provided with a curved surface 5 on which slides a correspondingly curved surface on the back of the movable jaw 13 carried by the arm 2. The jaw 11 is slidable on a guide 15 on the arm 3 and fixed in adjusted position thereon by a screw 12 having oppositely threaded ends which engage in threaded holes in the arm 3 and jaw 11 respectively. A curved surface 6 on the arm 3 coacts with a correspondingly curved surface or pin on the lever arm 2, the two arms being acted on by a spring 21 the ends of which are attached to a transverse member 22. The front part of the arm 2 is supported by a pin 10 on the arm 3 which engages with the curved surface 9. The surfaces 5, 6 and 9 have a common axis of curvature 4. A spring biased hook 17 pivoted to the jaw 11 and guided between projections on the arm 2 assists in correctly positioning the work between the jaws. In a modification, Fig. 6, only one handle is provided. The movable jaw which is maintained on the arm 3 by a leaf spring is provided with two plate members 27 having curved surfaces which slide on curved surfaces on each side of the arm 3, each plate being provided with a lug 28 to guide the hook. The movable jaw is interconnected with the handle 30 by a plate 31 and member 32 which are detachably connected by the pin 33. To swing the jaw into gripping position the member 32 is pressed inwards towards the handle 30 causing the oblique surface 34 at the end of the arm 32 to slide on the end of the arm 3 and the plate 31 to move to the right. In another modification the handle 30 and member 32 are replaced by a handle pivoted to the arm 3 and connected to the plate 31.