Patent GB-682522-A (GB)
Title: Improvements in mechanism for handling boards
IPC: B65G47/24
Filed: 1949-12-08
Abstract: 682,522. Conveyers. BLAIR, R. C.. and BRITISH PLASTER BOARD, Ltd. Nov. 28, 1950. [Dec. 8, 1949] No. 1593/49. Class78 (i). Building or like boards are fed by a first conveying means to a device for turning over alternate boards consisting of a stop positioned below and beyond the first conveying means for engaging one board in position leaning backwards towards the conveying means, while a succeeding board engages the first board and turns it over, the engagement with the first board preventing the succeeding board from engaging the stop, so that it falls without turning on top of the first board upon a second conveying means beyond the stop which thereupon advances the two boards together. As shown, the first conveyer which conveys the boards in the direction of their width, comprises a series of parallel endless belts 58, Figs. 3 and 6, which at their delivery end pass over idler rollers 65 and a driving roller 66. Rollers 65 are mounted on a pair of radius arms 75 pivoted at 76 to the conveyer frame and adjustable forwards and backwards by a rack 78 on each side of the frame engaged by a pinion 80 mounted on each arm 75, pinions 80 being actuated by a handle 82. The second conveyer comprises parallel endless belts 93 having a comb-like platform 98 at their receiving end. A flat plate 85 is pivoted at 86 to the outer end of the arms 75 and as arms 75 are moved slides in the gap between a stop 91 of resilient material and a beam 90. By this means the width of the plate 85 between stop 91 and roller 65 is adjusted to be somewhat less than the widths of the building boards being handled. In operation, boards having a smooth cream underside and a rough grey upper face are conveyed by conveyer 58, whereby a first board B1, Fig. 6, falls over the end of the conveyer 58 defined by rollers 65 onto the stop 91 and flat against the plate 85, being cushioned by the air pocket between it and said plate 85. A second board B2 engages the under face of board B1 at its upper projecting end and pushes it so as to cause it to fall forwards about its lower edge, whereby it is inverted on to the conveyer 93. Owing to the forward edge of board B2 being in frictional contact with board B1 the former overshoots the stop 91 and lands on top of the inverted board B1 on conveyer 93. Conveyer 93 feeds these pairs of boards, thus having their smooth faces in contact, over driven rollers 104, 105, Fig. 5, onto a pair of rails 107 which can be raised or lowered towards and away from a stop 110 by cams 111. Stop 110 can be placed in one of several notches corresponding to differing widths of board. Pushers 108 carried by endless chains 109 push the boards beyond the stop 110. By raising or lowering the rails 107 either the upper boards may be stopped by the stop so that only single boards are fed beyond the stop, or the pairs of boards can be fed beyond the stop, respectively. If desired, boards may be transferred between conveyers 58 and 93 without inversion of alternate boards by lowering rollers 65 by the rack and pinion gear to a position adjacent the stop 91 whereupon idler rollers 83 support the bands 58. Rollerways, transverse discharge therefrom onto endless bands. The boards pass side by side from a dryer (not shown) in threes over rollers the last of which is shown at 20, Fig. 3, to a stop 48. Beyond stop 48 are rollers 21, Fig. 3, carried by a rising frame 23, the bands 58 being disposed between adjacent pairs of rollers 21. Frame 23 can be raised and lowered through cranks 40 by a pneumatic cylinder 46 controlled by an electromagnetic valve 44, Figs. 3 and 11, and frame 23 is coupled by pivoted levers 50 to the stop 48 so that as the frame is raised, stop 48 is lowered and vice-versa. In operation, boards released by stop 48 pass along the rollers 21 until each reaches a depressable stop 51. Just before reaching stop 51 the boards close a switch 113 which causes a current to pass through the electromagnet coil 120 of valve 44 via three normally closed switches 122, 122A, 122B, so as to cause air to be released from cylinder 46 whereby the rollers 21 are lowered and the stop 48 raised to prevent further boards travelling onto the rollers 21. The boards are thus lowered on to the travelling bands 58 which carry them past switches 113A, 113B, which hold in the circuit until the boards have passed them whereupon the circuit is opened, causing valve 46 to supply air to raise frame 23 and lower stop 48 to receive further boards. If it is desired to reject a board as it passes over rollers 21, the corresponding gate 51 is depressed electromagnetically by operating one of the switches 122, 122A, 122B which completes the circuit through the corresponding electromagnet 55 of that gate.