GB983946A - Synthetic plastic container and blank and method of folding same - Google Patents

Abstract

983,946. Making plastics cartons. C. E. PALMER. July 18, 1963 [July 18, 1962], No. 28411/63. Heading B5D. [Also in Division B8] A method of making a tubular carton from an unscored blank of synthetic plastic sheet material, Fig. 7, comprises the steps of folding bottom end flaps 16, 18 and 28 at right angles to the rest of the blank by means of a blade 50 and a resiliently deformable die pad 48, Fig. 8, and then folding the blank longitudinally by means of a rotatable mandrel 68 and a system of resiliently deformable pads 66, Fig. 10. At the same time, fingers 76 and 78, 82 (not shown), press tongues 22 on flaps 16 into slots 20 and a locking tongue 26 on flap 28 into slot 24 to close the carton bottom and the carton is closed longitudinally by fingers 80, Fig. 13, which press locking tongues 14 on a side extension flap 12 into slots 4 in side wall 2. The preferred material e.g. bi-axially oriented polystyrene of between 5-15 mils. thickness, is such that when cold-folded through somewhat more than 90 degrees, any inherent relaxation characteristics are compensated for and a permanent right-angle fold is formed. This is achieved in the present invention by placing the blade 50 at an acute angle to the main portion of the blank and using a mandrel having undercut portions 72, Fig. 10, which co-operate with the pads 66 on rocker supports 54, 56, 58 and 60. The slots 4 and 24 are each formed by a pair of S-shaped slits and a transverse interconnecting slit and the tongues 14, 26 are so shaped that after insertion they form a tamperproof lock. The top of the carton is closed by flaps 30, 32, Fig. 7, folded by means of a folding plate and cooperating die supports having resiliently deformable pads (Fig. 17, not shown). The tuckin flap 36 may be replaced by an above-described tamperproof tongue and slot connection. U.S.A. Specification 2,954,725 is referred to.