Stabilized-platform weighing scale of novel design. . nvestigation and analysis of thesedefects that the present invention, which forms the subject ofthis paper, was evolved. The nature and causes of the difficul-19215°—18 2 8 Technologic Papers of the Bureau of Standards ties, to which allusion is made above, are shown analytically inthe following derivation: The dotted lines in Fig. 2 show a load the weight of which isequal to L, its center of gravity being located at a distance x fromthe vertical through the load knife-edge (3, 4). Given the no-menclature of Fig. 2, and calling T the stress
Stabilized-platform weighing scale of novel design. . nvestigation and analysis of thesedefects that the present invention, which forms the subject ofthis paper, was evolved. The nature and causes of the difficul-19215°—18 2 8 Technologic Papers of the Bureau of Standards ties, to which allusion is made above, are shown analytically inthe following derivation: The dotted lines in Fig. 2 show a load the weight of which isequal to L, its center of gravity being located at a distance x fromthe vertical through the load knife-edge (3, 4). Given the no-menclature of Fig. 2, and calling T the stress in the link 2, we ob-tain, by summation of moments, about (3, 4)— 2M = Lx-G1k-Th = oT_Lx-G1k. (1) 1 ~~~h Let Rx and Ry be the components of the reaction R at (3, 4) inthe X and Y directions, respectively. By summation of forces in the X and Y directions, we obtain—SFj, =-L-G1 +Ry=o, or Ry =L +GX (2) XI?X=-RX + T or RX = T (3) Ry L + Gj. (4) tan<x = -^= ^ Substituting the value of T from (1) in (4), we obtain— (L+GJh (5) tan a Lx — Gxk. Fig. 5.—Check-stabilized, equal-arm beam scale With this type, loose weights are required, in amount equal to theweighing capacity. Being inexpensive and, on account of simple construc-tion, long wearing and reliable, it has been much used in small businessof every sort. When the loads are carefully centered on the pans, the scalewill weigh with very satisfactory accuracy. To all of the familiar commercial forms illustrated in Figs. 3, 4, and 5,the invention which tortus the subject of this paper is directly applicable. This solution is given graphically in Fig. 2, and the force dia-gram is there extended to include also a solution for the reactionat the fulcrum pivot. As is shown by the above derivation, inall cases in which the resultant of the weights of the platform Bureau of Standards Technologic Paper No. 106
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