Patent GB-453130-A (GB)
Title: Improvements in or relating to measuring or recording instruments
Filed: 1935-03-04
Abstract: 453,130. Electric signalling systems. ELECTROFLO METERS CO., Ltd., Abbey Road, Park Royal, London.-(Republic Flow Meters, Inc. ; 2240, Diversey Parkway, Chicago, U.S.A.) March 4, 1935, No. 6715. [Class 40 (i)] [See also Group XIX] Comprises electrical devices wherewith each of a series of instruments such as pyrometers may be successively connected with an electric instrument working on the " null " principle and causing the readings to be indicated or recorded with characteristics distinguishing the particular instrument concerned. Potentiometer circuit. The galvanometer 12, Fig. 35, is connected by a lead 16 to a switch point 18 and by a lead 20 through a rheostat 22, 24 and lead 26 to a switch contact 28. The contacts 18, 28 connect through contacts 30, 32 with the rings 34, 36 of a double multiple switch 38, Fig. 31. Spring arms 40, 42 mounted on a shaft 44 are pressed against rings of contacts 56, 58 by a spacing block 41 of insulating material having curved faces and being mounted on the shaft 44 between the arms. The shaft 44 carries a pointer 46 moving over a dial 48 and the rings of contacts are connected to opposite sides of a number of pyrometers 60. Associated with the galvanometer is the usual calibrating circuit including a standard cell 62, battery 64, resistances 70, 72 and a calibrating rheostat 74, 76. The latter is so formed that a switch is pushed in to connect for calibrating and then turned to make the adjustment. Control by needle 14. A constant speed meter 92, Fig. 4, drives a shaft 88 which through worm gear 94, shaft 54 and gear 52, 50 drives the shaft 44 and consequently the multiple switch 38 and indicator needle 46. On the shaft 88 are cams 96, 98 of which the cam 96 through a bell-crank lever 100, Fig. 14, reciprocates a slide 104 having a turned-up end 106. This engages an arm of an open framework lever 108, Fig. 12, which co-operates with a stationary ledge 110 to grip the pointer 14 periodically. Pivoted about the top of the shaft 134 also are two feelers 112, 114 normally urged together by a tension spring 126, but opened against the influence of the spring when the short arms are engaged and moved by the left hand, Fig. 12, movement of the slide 104. These short arms have depending lugs engaging arcuate slots 120, 122 in a disc 124 loose on the shaft 134. The cam 98 rocks a lever 130 which raises a sleeve 132 on the shaft 134 and causes it to engage and open against the influence of springs 142, grips 140 which engage the bevelled edge of the disc 124 and clutch it to the shaft 134. The slots 120, 122 are so arranged, that when the pointer 14 is in the central position, Fig. 12, and the feelers engaged, the lugs just reach the front ends of the slots. The cycle of movement is such, that, starting from the position shown in Figs. 12, 14 where the disc 124 is clutched to the shaft 134 and the grips for the pointer 14 all released, supposing the pointer 14 to be now deflected from the central position, as the cycle proceeds, the grips 108, 110 grip the pointer and then the feelers 112, 114 of which one has to travel past the central position of the pointer taking with it the disc 124 which has now been released. As the slide 104 moves back, the disc is reclutched to the shaft and the gripping levers 112, 114 are forcibly brought to the position of Fig. 12, the disc and shaft 134 being turned an amount corresponding to the angular deflection of the pointer 14. The rheostat 22 is carried by the shaft 134 and is thus adjusted so that the pointer 14 swings back to zero. The angular position of the unsymmetrical characteristic shown on the dial 48 denotes the particular pyrometer selected, the reading being given on an indicator driven from the shaft 134. A recording chart driven from the shaft 88 has similar characteristics marked on it by mechanism positioned from the shaft 134.