GB400428A - Improvements in or relating to load indicators more especially for cranes - Google Patents

Abstract

400,428. Dynamometers. W Y LIE, H. N., 5, Clement's Inn, Strand, London. April 30, 1932, No. 31442. Divided on 400,932 and addition to 377,209. [Class 106 (ii).] Relates to load indicators for cranes &c. in which a pair of compressor heads movable towards one another are held apart by a strut adapted to bend under load, and consists in employing a strut made up of one or more steel plates the ends of which are clamped to the heads or otherwise fixed so that their freedom to incline is restricted. The frame 1 and arm 2 are hinged together at 3 and have fixed to them the heads 4, 5 and a strut 6 made of two flat spring steel plates clamped to the flat coplanar faces of the heads 4, 5 by flat blocks 7 and screws. A central clip 8 is attached to a rod 9 which moves a signal arm 10 when the strut is deflected on application of load to the arm 2. A deflection bias in the desired direction is given to the strut by the screw 12. In a modification the arm 2 is connected to the frame 1 on each side and near the middle by struts 6 connected together in the centre by a bar and the movement of the end of arm 2 under load is used to actuate the lever 10 directly. A further modification desciibes the lever 10 as actuated through a Bowden wire. In the form shown in Figs. 4 and 5, a pull on a tension member 13 is arranged to deflect the strut. The heads 4, 5 are rectangular bars clamped between the ends of the strut 6. Trunnion extensions 14 on the head 4 pivot in frame plates 1, 1 and the head 5 is pivoted to the side arms 2 which extend beyond the head 4 to connect with the member 13 by a pin. The arms 2 have slots which accommodate the trunnions 14 and allow relative movement between parts 1, 2. The spring plates of the strut are clamped at the centre by a part 8 pivoted to a rod 9 which operates the lever 10. The resistance of the strut is augmented by a spring 16 and a second pre-compressed spring 17 comes into play under the appropriate load. The strut may be formed by three spring plates riveted together at the ends, the centre one projecting beyond the others and engaging seating notches in the parts 1, 2.