GB375386A - Improvements in safe load indicators for cranes and the like - Google Patents

Abstract

375,386. Weighing-apparatus fitted to cranes. WALLS, A. G., 295, Broadstone Road, Heaton Chapel, Stockport. March 24, 1931, No. 8955. [Class 143.] A weigh-crane provided with a device which gives a visible or audible indication, or both, of the approach to the safe load comprises a sheave in a bight of the hoisting rope mounted in a sliding or swinging member which moves substantially in a straight line against the resistance of a spring. As applied to a jib crane, the safe load at any angle of the jib is shown on a uniform scale of weight and actual load on the crane is shown on the same scale. As shown in Fig. I, a sheave 7 in a bight of the hoisting rope is carried on a rod 5 sliding in bearings in a housing 2 on the jib against the resistance of a spring 14. Additional springs may be arranged as at 16, or concentric with the spring 14 or alongside of it, and the sheave 7 may be in a bight which bears only a part of the load. The springs may be coated, e.g. with chromium to resist rust. The rod 5 carries a bracket 19 connected by a wire, or a band 21 or the like, to a drum 22 which carries the weight indicator 24, 24a moving over a scale 26, Fig. II. In a modification, Fig. VI, the sheave 7 is mounted in an arm 43 pivoted at a point P which is beyond the radius of the sheave. A quadrant 44 on the arm 43 is connected by a flexible member to a small quadrant 45 on a lever 46 which is restrained by a spring 47 and is connected by a quadrant 48 and flexible link to the weight indicator 24. In another modification, Fig. VIII (not shown), a rod such as 5 restrained by a light spring 14 carries a rack connected through spur gearing with a rack on the frame of the sheave 7, the travel of the rod 5 being greater than that of the sheave 7.