Patent GB-692996-A (GB)
Title: Improvements in weighing scales
IPC: G01G1/00
Filed: 1949-10-29
Abstract: 692,996. Weighing-apparatus. WILLIAMS, L. S., and TOLEDO SCALE CO. Oct. 29, 1949, No. 27754/49. Class 143. In a weighing scale of the kind having a liquid seal for the indicator and counterbalance mechanism housing 2 comprising a cup 59 movable with the steelyard rod 35 and a normally fixed cup 58, an auxiliary function mechanism within the housing is operated by an external control device which moves the cup 58 axially. This auxiliary function mechanism may be a counterweight locking device, or a device which gives either a visual indication, or sets type, denoting the quantity of loose weights supported by the counter-balancing mechanism. In Fig. I a rolling sector type pendulum counterbalance mechanism as described in Specification 654,104 is contained within the housing 2 and the steelyard rod 35, connected to the power ribbons 37, is connected at its lower end to an intermediate lever 24 plate fulcrummed at 25 and carrying an adjustable zeroizing weight 53. This lever. is connected by a rod 22 with the power pivot of a double steelyard 4; 5 plate fulcrummed at 10 and carrying a tare adjusting weight 6 and an auxiliary load counterbalancing weight 7, a dash pot 31 serving to neutralize vibrations transmitted to the mechanism by the rod 18 which is connected with the load platform (not shown). Rotation of a wheel 55 first causes a rod 56 to lift a finger 33 which locks the steelyards and then causes a rod 57 to lower the cup 58, together with perforated plates 62 secured thereto, which plates engage horns 63 on the pendulums and thus lock said pendulums. In a modification. Fig. VII, the liquid seal comprises a pair of cups 100, 112 and movement of the lower cup is effected by an external lever (not shown) which changes the capacity of the scale by depositing loose weights on a beam, movement of the cup being multiplied and transferred to a weighing range indicator 110 by pinions 106 rotatably mounted on cup 108 and engaging fixed racks 104 and movable racks 108 secured to the indicator 110 which is read under a magnifier 111. In a further modification, Fig. IX this indicator is connected by a rack 114 and pinions 115, 119 and a rack 120 with a type setting bar 127 which indicates the range on one side of a ticket when . is stamped on the other side by the pendulum controlled wheel 128 at 129. In another modification, Fig. X, the movement of the lower cup 100 is communicated directly to an indicia carrying bar 141 by an arm 140 so that both the range and rotating indicator reading are displayed under the magnifier 130. In all the above modifications the complete head assembly is adjustably rotatable about a vertical axis and, as shown in Fig. II, the connection between the indicator spindle 46 and the pendulums is effected by a yoke 66 which is pivoted to the pendulums 50 so that it rises and falls as the pendulums roll on their fulcrum ribbons. This yoke carries a bearing 80 which is spring coupled with a cone pointed pivot 78 on the indicator operating rack 44, and the rack carries a counterweight 77 arranged so that the centre of gravity of the complete rack assembly is located at the tip of pivot 78 thus the rack is in neutral equilibrium. The plate fulcrums 10, 25 each comprise plates 27, 26, Fig. V, respectively secured to the beam and to a hook shaped member 25 which by resting on a support bar 28 allows the beam to slide when jarred without buckling the plates, a pin 29 loosely engaging a hole 29<SP>1</SP> in the member 25 locates this member and, to ensure that this loose engagement does not cause errors in weighing, the member is pivoted on the bar 28 off centre so that the inner side of hole 29<SP>1</SP> normally engages the pin 29.