GB603359A - Improvements in flexible curve devices for drawing office and other purposes - Google Patents

Abstract

603,359. Flexible rulers. DAVIDSON, A. D. Oct. 18, 1945, No. 27402. [Class 97 (iii)] The rule 3 is bent to the desired plane curve by the application of a compressive force to the ends of the rule and of torques at one or more points. of the rule, these forces being applied by mechanisms, e.g. worm-gearing, which itself holds the rule 3 in the set position. As shown, the angle between the pivotally interconnected arms 1, 2 of the V-shaped frame across the mouth of which the flexible and resilient rule extends, is varied by rotating rod 16 whose ends are provided with screws of opposite hands which engage with corresponding screw-threaded elements 17, 18 on the arms to apply a compressive force to the rule. Torques are applied at the ends of the rule by means of worm-wheel mechanisms 12, 13 operated by knobs 10, 11. The rule may be constrained at any point along its length by stop 31 carried by bar 30 slidable in an aperture in the pivot of arms 1, 2. Stop 31 can be axially adjusted in terminal block 46 so as to be brought into contact with the inner or outer surface of the rule or with its edge. A slidable cross-head 32 secured to bar 30 by set-screw 43 is pivoted to rods 33 and 34 which pass through, and are clamped at 44, 45 to sleeves 35, 36 carried by arms 1, 2 and are adjustable in relation thereto by screw means operated by wheels 41, 42. Rule 3 has a reflecting surface whereby any suitable optical means may be used to determine the radius of curvature or tangent to the curve at any point thereof. Locating members 28, 29, are slidably disposed in adjustable pillars 24, 25, and terminate in steel points which on pressing down serve to locate the instrument. Small and large wheels 19, 20 are provided on the ends of the rod 16 for making coarse and fine adjustments. Scales and indicating marks as shown are provided for all the adjustable elements 1, 2, 12, 13 and 30.