GB886044A - Proportional folding machine - Google Patents

Abstract

886,044. Folding fabrics. McGRAW-EDISON CO. Aug. 17, 1959, No. 28100/59. Class 42 (2). A method of folding a flat flexible article along proportionately spaced transverse folding lines as it passes along a path past a folding zone, comprises reducing the advance speed of the leading portion of the article at and beyond the folding zone while maintaining the advance speed of a trailing portion of the article as it approaches the folding zone whereby to cause an intermediate portion of the article to drape in a two-ply loop in the vicinity of the folding zone, and continuously and progressively increasing the length of the leading portion and the looped portion while maintaining substantially a constant ratio between the lengths of the leading portion and the looped portion. Apparatus for performing the method, to fold an article into four, is shown in Fig. 1. An article to be folded is delivered on to pick-up conveyer 27 and is carried up belt run A and then down a belt run B where the leading edge is caused to interrupt a light beam from mirrors of a control mechanism. The leading edge drapes to the rear of roller folder 60 and after a time delay the folder is swung about pivot 67a by the control mechanism so as to bring the leading edge into contact between the folder and abutment fingers 61 (Fig. 10). After a further short delay the abutments 61 are withdrawn to allow the leading edge to be fed by roll 62 at a reduced speed proportional to the initial speed so causing a looped two-ply portion to form on the front side of folder 60 (Fig. 11). At the same instant the control mechanism causes mirrors 93, 101 to be moved upwards at the same speed as the leading edge is moving downwards. When the light beam from mirrors 93, 101 meet the trailing edge of the article, the control mechanism causes the roller folder 60 to swing forwards and present the article to the bite between ribbons 46 and roll 49 (Fig. 12) so that the article is fed therebetween and on to table 28 in a four-fold condition. The roller 60 is hollow and is fed with compressed air and is constructed so that jets of air force the article into the bite between roll 49 and belts 46 at the desired moment. With the arrangement shown, if the normal speed of feed of the article is V then the leading edge is fed downwards at V/3 and the mirrors upwards at V/3. This causes the loop part to also advance downwards at V/3 so that the article is properly divided in four. The mirrors 93, 101 are arranged on chains and are a part of a light system (Fig. 9) from source 92 to mirror 93 across horizontally to long mirror 99 which turns it through 90 degrees on to mirror 100 which turns it back through another 90 degrees on to mirror 101 which reflects it vertically upwards on to a photo-electric cell 105 (Fig. 1). The horizontal beams are arranged between flights of belts B and the spacing apart compensates for any irregularity in the line of the leading edge so that the control mechanism is not operated until the whole leading edge (or trailing edge) has passed the light beam. The apparatus can be adapted to make a single fold by driving the proportioner roll 62 at half speed and allowing the trailing edge to drop down in front of the roller folder 60. A by-pass device is provided and consists of plate 52, 53 which if pivoted about pivot 52a causes an article from belts A to be fed straight over to table 28 without passing down through the folding device.