Patent GB-1502601-A (GB)
Title: Apparatus for size monitoring articles on a conveyor
IPC: G01B5/10
Filed: 1974-02-18
Abstract: 1502601 Size monitoring articles on a conveyer ROCKWARE GLASS Ltd 7 May 1975 [18 Feb 1974] 7339/74 Headings G1M and G1N Articles such as bottles moving on a conveyer 200, Fig. 1, pass between a fixed but adjustable P.T.F.E. roller 48 and a similar roller 48 attached to a plate 203 swingably supported on a bracket 34, Fig. 4. A stop 39 is adjusted to just touch the plate 203 when the distance between the two rollers 48 is just smaller than the size of the articles to be checked, and a micro-switch 96, see also Fig. 6 (not shown) may be adjusted by a knob 29 so that when the rollers 48 are held apart by a bottle of maximum permissible size the switch is just about to make. The movement of the plate 203 is damped by an oil dashpot arrangement 21, see also Fig. 8 (not shown) and a solenoid 91, see also Figs. 9 and 10 (not shown) may be energized by the switch to operate an article reject arm 54 to push a faulty article off the conveyer. Both sides of the apparatus of Fig. 1 may be adjusted in height by means of threaded support pillars see also Figs. 2 and 3 (not shown). In operation, as the plate 203 swings each time a bottle passes between the rollers 48 and arm 33 is moved which may, if the bottle is oversize, operate the switch 96, solenoid 91 and reject arm 54. If both oversize and undersize bottles are to be removed then switch 96 is replaced by an LVDT 250, Fig. 11 which has 0 volts output when rollers 48 is in its relaxed position and 1 volt output when the arm 203 is deflected to a maximum. When 203 deflects, the output from the LVDT is fed to a comparator ICI which operates relay RLA when the reference voltage is exceeded. This allows relay RLB to pull in through contacts RLA1 and records the bottle on a totalizer counter and inspection lamp 252. RLC is not allowed to energize due to RLA2 normally closed contacts opening before RLB2 contacts close. The voltage from the LVDT continues to rise and the peak detector circuit comprising circuits LM101 and LM102 comes into action. The 0.22ÁF capacitor is allowed to charge up to the input voltage and this is displayed on the meter which has set limits on its face. RLB1 contacts are open so that the capacitor maintains its charge and even as the voltage from the LVDT falls as the bottle leaves the rollers 48 it continues to give an output to the meter relay 254. This is the maximum voltage from the LVDT representing the maximum deflection of the roller 48 and corresponds to the actual size of the just passed bottle. No output is obtained from the meter if the bottle is of acceptable size but otherwise a positive output would appear on one side of the RLC1 contacts. As the bottle moves away from the rollers RLA would drop out on the lessening voltage. RLB however falls out slightly later and hence RLC is energized through RLA2 and RLB2. RLC1 closes to allow the silicon controlled rectifier TH1 to conduct and RLB and RLC drop out, but TH1 continues to conduct. This puts 12 volts on the timer LR171E and after delay to allow the bottle to reach the reject point RLD is energized to operate the rejector through contacts RLD2 and RLD3 and reset TH1. The meter has previously been set to zero again as RLB1 contacts make.