Patent GB-388133-A (GB)
Title: Improvements in or relating to bags provided with transparent or semi-transparent windows
IPC: B31B19/82
Filed: 1931-11-16
Abstract: 388,133. Making window bags. ELLENS, W. E., Tresco Brow, Chesham Road, Berkhampsted, and DICKINSON & CO., Ltd., J., Apsley Mills, Hemel Hempstead, both in Hertfordshire. Nov. 16, 1931, No. 31756. [Class 94 (ii).] The manufacture of paper bags of the type having window openings covered by patches of transparent paper consists in providing a bagmaking machine with means adapted to cut or punch openings in a travelling web of bag material to form windows therein, to provide the said openings with a surround of adhesive and to apply a patch in position over the opening to close it. Paper web 1 is drawn from a supply by rolls 6, 7 and is fed towards the left, Fig. 1, at a constant speed throughout the operations of punching, gumming, and patch applying. The window punching mechanism comprises male and female dies on a carriage 50 reciprocated by slotted discs 28, on shaft 27, which, through rods 30, reciprocate sliding shafts 32 to which the carriage is attached. A cam 62 also on shaft 27, periodically moves the lever system 60, 59, 58, 51 to depress the male die, against spring action, to punch windows in the travelling web. Attached to the die carrier is an extension 67 which carries the window gummer 4. A revoluble roller 87 horizontally reciprocated on rods 83 by a camactuated lever system 71, 73, 75, 77, applies gum from an adjustably-mounted bath 91 to the bottom of the gummer 4 when the latter is in its raised position. The distance between the cutting dies and the gummer 4 is a bag length so that during one downward motion of the carriage 50 a window opening is stamped out of the web and the preceding one is framed with gum, the pressure of the gummer on the web being taken by a horizontally reciprocated plate 141. The web now reaches the position when a patch is to be applied to each aperture and the patches are either cut from a web 126 or supplied from a pile or wad. In the first method, the web 126 is intermittently advanced by a ratchet mechanism 129, acting on a draw roll 120, the material overlying the knife 112 The coacting knife 115, carried by the underside of the patch applying device 5, sweeps out a path 143 and sheers a patch length from the web. A blast of air from a pipe 116, coacting with suction through pipe 110 and apertures 111 on the under surface of the patch applying device 5 ensure the positioning of the patch thereon before application to the moving web. The patch is applied to the web by the vertical reciprocation of the patch-applying device 5, this latter being also horizontally reciprocated by reason of its connection with the sliding side shafts 32, through cam and link connections 103, 104, 106. In a modified method where the patch is supplied from a wad, the wad 150 is contained in a holder and held by light springs at the bottom. The holder is given an approximately circular path by the combined motions of cams 103, 166 and levers 104, 164 and passes a member 173, which, contacting with a spring-urged locking detent lever 169 releases a weighted plunger 152 which imparts a sharp blow to the top of the wad thereby driving the lowermost patch into contact with the gummed window opening below. The web may be given a longitudinal strip of paste 180 at any part of the machine, and after punching at 181, gumming at 182 and patch applying at 184, the web is formed into a tube which passes to known apparatus 186 for severing it into bag lengths, bottom forming means at 188 and a collecting section 189.