Patent GB-599679-A (GB)
Title: Improvements in or relating to apparatus for controlled feeding of materials to receiving means
IPC: C08B1/10
Filed: 1944-04-28
Abstract: 599,679. Weighing-apparatus fitted to conveyers. BRITISH CELLOPHANE, Ltd. April 28, 1944, No. 8047. Convention date, April 29, 1943. [Class 143] [Also in Groups XXX and XXXV] In material-feeding apparatus of the type in which a loaded feeding device or carrier is balanced on a beam scale provided with an adjustable poise or weight which is moved at a predetermined rate along the beam towards the fulcrum, so that the variation of the balance controls the rate of discharge of the material from the carrier to a receiver, means is provided for stopping simultaneously the movement of the poise and the discharge means for a period of time sufficient to permit loading of the carrier, whereupon the poise is set automatically to a point of balance corresponding to the load, after which a compensating weight is added to the carrier to produce for a predetermined time an out-of-balance of the poise and an uninterrupted feed whereby the amount of material discharged in that time exceeds the amount that would otherwise have been discharged by a weight equal to the compensating weight, thereby compensating for the weight of material that would normally have been discharged in the time taken for reloading. In the example, sheets C of wood pulp or cotton linters are fed along an endless conveyer belt 10 into a chute 12 associated with means for the preparation of alkali cellulose, the sheets being separated individually from the stack by means operating as described in Specification 549,610, [Group XVI]. The conveyer system is supported on a scale comprising a base plate 20 supported on a pair of levers 21 which are pivoted at their outer ends and linked together at their inner ends where they are connected to a tie-rod 22 depending from a scale beam 23 pivoted at 24. The poise or weight 25 is carried by a screw-threaded shaft 26 mounted in end bearings on the beam and coupled through a variable speed gear-box 34 to a constant speed motor 31. The outer end of the beam 23 carries an operating arm 27 adjacent to a lever 28 on a mercury switch 120, so that when the beam is unbalanced due to excess weight on the conveyer, the switch is operated to energise a motor 14 which drives the conveyer, while motor 31 drives the poise screw 26 and advances the weight 25 inwardly. When a balance is reached the motor 14 stops, but the weight continues to advance until balance is upset, and motor 14 is restarted. A signal lamp 128 lights up during running of motor 14, and goes out when balance is attained. When reloading of the conveyer becomes necessary the operator presses a push button 100 during the condition of balance, thereby energising a latch in relay switch 110 and a relay switch 111 which opens the connection of motor 14 to a line L2 and connects that line to solenoids 101, 102 and 106. Solenoid 101 opens a 3-way air valve 90 which causes:- (1) The lowering of an electromagnetic beam stabilizer 62. (2) The engagement of a clutch 53 whereby a continuously rotating motor 55 operates timing mechanism which restarts the conveyer feed after the pre-assessed time for reloading. (3) Actuation of a lever 72 to lift the compensating weight 70 from the conveyer platform. Solenoid 102 operates a locking lever 80 which locks the scale beam 23, while solenoid 106 disengages a clutch within gear-box 34 and prevents operation of poise screw 26. The timing mechanism comprises a continuously rotating constant-speed motor 55 which is geared to drive slowly a pair of concentric discs 50, 51 which make one revolution during the reloading cycle. Disc 50 carries a lug 56 arranged to break contact with a switch 122 and allow it to close and, after the reloading, a lug 57 on a disc 51 closes momentarily the contacts of a switch 123 which operates to unlock the scale beam. Since the latter is now unbalanced its end is lifted to close mercury switches 120, 121 in sequence, with the result that the motor 31 drives the poise screw 26 in reverse at high speed towards a position of balance. When only slightly out of balance the beam opens mercury switch 121 and stops the high speed reverse movement, the slow speed reverse being operated until exact balance of the beam is attained. The whole apparatus, save for the timing mechanism, then remains inoperative until the end of the interval predetermined by the timing mechanism which then opens the switch 122 to close the three-way air valve 90. This disengages the timing mechanism and replaces the compensating weight 70 on the scale. and the clutch is re-engaged to drive the screw 26 and move the poise 25 at uniform speed towards the fulcrum. The circuit of motor 14 is also closed and its action again controlled in response to successive unbalanced and balanced conditions of the scale during normal operation until reloading again becomes necessary.