Patent GB-297415-A (GB)
Title: Improvements in or relating to weighing scales
IPC: G01G1/26
Filed: 1928-08-11
Abstract: 297,415. Barnes Scale Co., (Assignees of King, B. W.). Sept. 21, 1927, [Convention date]. Pendulum-weight apparatus. - Relates to a weighing scale wherein the weighing capacity may be increased by the addition of a counterweight to a main load lever of the first order having bearings at one end to receive the load, and being adapted at the other end to counterbalance the load. According to the inven. tion a capacity arm having a capacity weight at one end is adapted for movement so that the weight may be placed in or out of an operating position of engagement with the counterbalancing end of the main load lever, and the capacity arm has spaced bearing members located at the weighted end for moving into contact with the main load lever and spaced knife-edge. bearings at the other end for moving into contact with substantially flat bearing surfaces located therebelow when the arm is moved into its operative position, the said bearing members being adjustable relative to the weight so that the knife-edge bearings contact substantially equally with their respective bearing surfaces. The load-receiving platform 15, Fig. 4, is pivotally mounted upon a framelike arm 10 pivoted on knife-edge bearings 11. Knife-edges 17 projecting from the sides of the arm rest on agate bearings carried by upright struts 19 the lower ends of which rest on knifeedges 21 at one end of the main load lever 4 fulcrumed on knife-edges 6 and counterweighted at the end 7. The knife-edges 11, 17 are retained on their agates by means of links acting upon opposed knife-edges. A knifeedged link 25 engages a member 27 depending from the platform support. The main load lever 4 carries a pin point bearing 67 engaging a stirrup 68, Fig. 7, connected by a flexible ribbon 66 to a pendulum lever 62. In the unloaded position of the scale the pendulum is maintained in its raised position by the counterweighted end of the lever 4. When a load is placed suddenly on the platform 15 the point bearing 67 temporarily leaves its bearing on the stirrup 68 and thus avoids buckling of the ribbon 66. The pendulum swings down under the restraint of a dash-pot 70 located within the stirrup, until the point bearing 67 is reengaged. Loose-weight apparatus.-When it is desired to increase the weighing capacity of the scale a shaft 90, Fig. 4, is turned by means of a handle outside the cover thus withdrawing a support 91 from beneath the capacity arm 76. Projections 86 on the weighted end 75 of the arm fall into V-shaped bearings 88 on the main lever, and knife-edges at the other end of the capacity arm sink on to flat adjustable bearing- surfaces on the frame. The weight 75 is provided with an insert 82 adjustable by means of three screws to adjust the centre of gravity of the weight and to ensure that the knife-edges at the other end of the capacity arm engage their flat bearing-surfaces with substantially equal pressure. When the capacity arm is raised to the position shown, clear of the main beam, the weight 75 pushes up a rod 94 and displays on an indicator 92, Fig. 7, the fact that the capacity weight is out of operation. When the capacity arm is lowered the indicator falls on to a stop and shows that the capacity weight is in use.