Patent GB-1129002-A (GB)
Title: Conveyor system for regulating the flow of laminar articles
IPC: B07C1/02
Filed: 1966-05-23
Abstract: 1,129,002. Conveyers; sorting postal mail. FMC CORP. 23 May, 1966 [24 May, 1965], No. 22812/66. Heading B8A. General arrangement.-Postal letter mail disposed singly, in groups, or in mixed bunches, only pre-sorted to the extent that they are of average length and are all standing on their long edges, are fed by a series of conveyers, Fig. 1 (not shown), Fig. 1B (not shown), which are arranged so as finally to present the letters in a steady flow, singly and separated. Flow limiting means.-The letters are initially fed on an endless belt (10), (Fig. 1, not shown), between guide rails (12), (12) so as to pass between opposed but oppositely rotating flowlimiting endless belts (80), (82). These belts run at fast or slow speed according to the accumulation of flow at a buffer conveyer B. The letters then pass on to a belt 22 and pass a spring loaded flow-restricting pressure finger (28) which operates in conjunction with stepped guide-rail sections (26a), 24a. The belt 22 feeds a suction type belt 178 with which is associated a flow restraining member 182. This is retractable under the action of a solenoid (196), (Fig. 8, not shown) which is energized in response to signals derived from photo-cells P.C.1 and P.C. 2. If the light of cell P.C.2 is not obstructed by a normal flow of letters as determined by a timer (T), (Fig. 25, not shown) solenoid (196) is energized to retract the member 182. The latter is returned to normal position when flow is resumed, but under abnormal flow conditions it is caused to retract and return cyclically arranging the lap of the letters in the correct sense. From the belt 178, the letters are fed by accelerating edge-feeding belt 39 and accelerating roller 36, into the nip of opposed belts 264, 248. The opposed runs of these belts are disposed at an angle to the direction of feed of the belt 39 with the result that the trailing end of each letter is bent towards the belt 248. As the leading end is drawn between the belts 248, 264, the next following letter is thus engaged between the belts 248, 264, with the overlap being necessary formed in such a manner that the leading end of each letter is adjacent the belt 264 and the trailing end is adjacent the belt 248. Overlap in this sense is necessary for the letters to be correctly entered in the helical coils of a screw conveyer B to which it is fed by a vacuum belt 50 and a horizontal belt 44. Screw-type buffer-conveyer B.-This is associated with an edge-feeding delivery belt 54 and its output feeds a vacuum belt 71 which draws the letters one-by-one from a stack (L) (Figs. 18-23, not shown), which tends to form at the downsteam end of the conveyer B. If the stack (L) tends to increase, it causes the helix 64 to be displaced axially against a spring (350), (Figs. 12 and 14, not shown) thereby progressively causing the helix mounting boss (342) to expose photo-electric cells (PC3), (PC4), and (PC5), (Fig. 21a, not shown) from their normally eclipsed condition. These are arranged in a control circuit (Fig. 21, not shown) which is associated with slow and fast windings (S) (F) respectively of a two speed electric motor (86), (Fig. 3, not shown) driving the flowlimiting belts (80), (82). Thus when the stack (L) is large the winding (F) is energized otherwise the winding (S) in operation.