Patent GB-705181-A (GB)
Title: Improvements in or relating to automatic weighing apparatus
Inventor: CONACHER JAMES ERNEST
IPC: G01G19/00
Filed: 1951-03-29
Abstract: 705,181. Weighing apparatus. BLAW KNOX, Ltd. March 28, 1952 [March 29, 1951], No. 7309/51. Class 143 A weighing machine comprises a movable lever 1 connected by a shackle 9 to a weighing scale having material to be weighed fed to it; a wire 32 extending from the lever 1 to and over a segment provided on a shaft carrying a pendulous counterweight, the arrangement being such that pivoting of the lever about its fulcrum 6 causes rotation of the counterweighted shaft which operates a weight - indicating pointer; and a rod 58 connected to a housing 57 carrying three freely mounted contact rods 62, 63, 64 (Fig. 2) which successively disengage and permit to open three switches during feeding of the material, the first switch decreasing the rate of feed, the second stopping the feed, and the third, if operated, indicating overloading to an operator by lighting a signal lamp. According to the invention several such machines are mounted in parallel for weighing and proportionately mixing the constituents, for example of cement, concrete &c. According further to the invention the switches for each machine are mounted on a spring biased support 69 whose upward movement is limited by one or other of bolts 82 on a shaft 80 which can be axially moved without rotation, and it is common to all the weigh machines, for adjusting the proportions of the mixture, the position of the support 69 determining the point at which the switches 73, 74, 75 are opened. To set up the machine the screw 27 is adjusted to bear on the lever 1 until the desired weight is indicated on the weighing scale (one for each weighing machine). With a manually depressible spring biased box spanner 91 the heads of the bolts 82 are then rotated until the rod 63 has just opened the central i.e. feed stopping switch 74 as indicated by a lamp controlled by the switch 74 becoming illuminated on the operator's switchboard. This is done for each of the bolts 82, each determining a different weight. The bolt 27 is finally released and the counterweights 11, 12 adjusted to allow for the weight of the weighing hopper. A counterweight 14 permits further adjustment, e.g. for the proportion of water in the sand constituent. Mix change mechanism (Fig. 5) Comprises an adjusting handle 99 which to be operated must first be pulled outwardly to disengage locating pins 101, this moving a collar 104 to tilt a yoke 107 and arm 109 against the action of a counterweight 110 and through linkage 111, 112 rotating a shaft 113 having arms 131 (Fig. 1) bearing on the undersurface of pivoted adjustable supports 69 so that the supports are tilted clear of all the bolts 82. Rotation of the handle 99 (Fig. 5) then operates through gearing to rotate a nut 118 mounted on a quick-threaded portion of the shaft 80 to slide it transversely. A collar 123 on the shaft 80 carries a spring-loaded plunger for contacting terminals to indicate, by closing a lamp circuit, which of the bolts 82 is operative. Recording mechanism. During weighing a chart is continuously driven between rollers and parallel lines inked on it by a grooved roller. Each weigh indicator operated from the wire 32 operates through a belt, a shaft carrying a depending rod which transversely moves across the chart a U- shaped pen, one end of which depends over one edge of a transverse trough carrying ink and the other end engages the chart, the lateral deflection being proportional to the weight. When the operator presses a switch to empty the weigh hopper a solenoid is energized and through linkage presses one edge of the chart into engagement with exposed type of clock-controlled time and date mechanism so that the time and date is printed on the chart.