Patent GB-801368-A (GB)
Title: Improvements in or relating to method and apparatus for folding box blanks
IPC: B31B50/54
Filed: 1955-09-13
Abstract: 801,368. Folding paper. LABOMBARDE, R. A. Sept. 13, 1955 [Sept. 29, 1954], No. 26161/55. Class 100(1) [Also in Group XVII] In folding mechanism for folding box blanks the leading and trailing flaps on the blanks which are advanced in one direction, are folded upwardly and towards each other by means of a hooked finger which moves forwardly with the blank after effecting a folding, and a radially rotating finger respectively. The machine shown is adapted to fold blanks 24 as shown in Fig. 1A comprising a bottom panel 25 side flaps 26, 27, end wall flaps 30, 31 which are provided with tabs 43, 44, 45 and 46, and attachment flaps 35, 36, 37, and 38. The folding machine is divided into two main zones 55 and 57 (Fig. 2) which effect folding of the inner flaps 30, 31 and outer flaps 35-38 respectively. The zone 55 is subdivided into zones 60, 61, 62 wherein folding of the tabs 44, 45, folding of the flap 30 and the tabs 43, 46, and folding of the flap 31 respectively take place. The blanks are initially fed into the zone 60 by pairs of upper and lower conveyer chains or belts 64, 65 and 66, 67 which run around sprockets suitably journalled in frame plates 75, 76 of the machine, positioned so that the chains or belts engage the side flaps 26, 27 and attachment flaps of the blank only, thus leaving the central portion of the blank free. Under the path of each leading tab 44, 45 a stationary underfolding channel or guide 84 or 85 is mounted, above each of which is a resilient leaf spring 86 or 87. The free ends of the springs 86, 87 press the leading tabs downwardly out of the horizontal path and into the underfolding channels so that the leading tabs are folded with respect to the leading flap 31. The blanks then pass to zone 61 between two sets of oppositely disposed upper and lower conveyer belts 92, 93, 94 and 95 which also carry the blanks through the zone 62 and which are aligned with the conveyer chains 64, 65, 66 and 67. A pair of elongated supporting bars 96 extend under the path of the underfolded leading tabs to prevent their unfolding. In the zone 61 the trailing flap 30 and tabs 42 and 43 are folded. The trailing flap folding mechanism may be as described in Specification 784,015 and comprise an endless carrier 113, the upper stretch of which advances at a less rate than that of the blank, carrying hooked folding fingers 115, 116 which engage and upwardly fold the flap 30. Preferably a continuously rotating holddown arm 126 on a shaft 127 is provided for holding down the panel 25 of the blank during folding of the flap 30. The trailing tabs are folded by rigid bars 135 supported on a bracket 136 carried by a transverse bar 130. The bars 135 engage and fold back the trailing tabs during the upfolding of the trailing flap by the fingers 115, 116. In the zone 62 the leading flap 31 is folded up by folding fingers 120 which rotate in an anticlockwise direction as viewed in Figs. 2 and 11, Fig. 11 showing an elongated diagrammatic view of the machine. The leading flap folding mechanism is described in Specification 801,097. The trailing tabs are held down after folding by projections 142 on the fingers 115, 116 until the blank is clear of such fingers, and the leading flap is initially held down after folding by the fingers 120 and by a holddown bar 129. After folding of the inner flaps and tabs in zone 55 the blank passes to zone 57 where the outer leading and trailing flaps 35-38 are folded by rotating fingers 150 similar to the fingers 120, and hooked fingers 140 similar to the fingers 115, 116. Co-operating holddown devices 152 and 149 are also provided. The blank is guided through the zone 57 by sets of upper and lower belts 154, 155, 156 and 157 which engage the inner folded portions of the blank thus leaving the outer edges free for folding. The operative parts of the machine are driven in synchronism with each other and are relatively adjustable for folding different sizes of blanks.