GB191400989A - Improvements relating to Pivot Joints for Callipers, Compasses, Dividers and other purposes. - Google Patents

Abstract

989. Humpage, A. J. Jan. 14. Compasses and dividers.-Relates to callipers, compasses, dividers, &c. of the kind in which rough adjustment is first made between one of the limbs and an arm mounted on the pivot of the joint and the final adjustment is then made between the arm and the second limb and consists in (1) constructing the pivot joint so. . that the frictional engagement between the first limb and the arm is adjustable by a member disposed eccentrically with regard to the axis of the joint, and independently of the frictional engagement between the arm and the second limb which may be separately adjustable by forming the joint pivot as a screw, and (2) improved means for obtaining the final adjustment. (1) The limbs 1, 10, Fig. 4, are provided with recessed heads 2, 3 to receive a'split ring 4, Fig. 5, provided with a hole 5 for the passage of the pivot 12 and a conical hole 8 to receive an expanding plug 9, the stem of which passes through a slot in the second limb 10 and is screwed into the arm 11. The ring 4 is tapered so that, when the plug is screwed in, the arm 11 and limb 1 are locked together but leave the limb 10 free to move. (2) In one form the final adjustment is obtained by a screw rotatably mounted in a projection on the arm 11 and screwing through a projection on the limb 10. In the form shown in Fig. 3, a screw fixed between projections 19, 20 on the limb 10 carries a nut 18 which engages between the two parts of the arm 11 which is split longitudinally.