Patent GB-817807-A (GB)
Title: Arrangement for producing packaging bags
IPC: B31B160/10
Filed: 1956-04-16
Abstract: 817,807. Making paper and like bags. HESSER MASCKINENFABRIK-A.G., F. April 16, 1956 [April 15, 1955], No. 11568/56. Class 94(2). Apparatus for forming bags from a continuous web of heat-sealable material folded to tubular form, comprises gripper means for advancing the web and sealing it transversely, suction means to open the advancing end of the tube, and a reciprocating gripper device to grasp the open end and pull the tube onto a mandrel. Web from a roll 2 is folded longitudinally by known means 4 and its edges joined by a heat sealer L while being advanced between rollers 3, 31, 5, 5<SP>1</SP>. It is then transversely sealed by jaws H, H<SP>1</SP> which advances with it the length of the web necessary to make a bag and then return to form a further seam. In an alternative form (not shown) the longitudinal and transverse sealing means are combined in a single element. The transverse seam is gripped by jaws K, K<SP>1</SP> reciprocating with the jaws H, H<SP>1</SP>, which cool it while advancing it towards one of a series of mandrels 7 mounted on a rotating turret (not shown). Each mandrel incorporates a pair of grippers 9, 9<SP>1</SP>, Figs. 10-12, moveable along it by roller and cam means 8b, 8h, 15 operating on a bush 8 carrying the grippers. The moveable jaws 9<SP>1</SP> of the grippers are operated by movement of a member 10, secured to a member 8a, relative to the bush 8, the bush 8 itself being moveable by the cam means 8h, 15. The member 10 has collars engaging arms 9c integral with the jaws 9<SP>1</SP>. Cam 15 also operates the jaws H, H<SP>1</SP>, K, K<SP>1</SP>. Movement of an extension 10c of the member 10 causes pivoting about axes m and inward collapse of pivoted corner elements 7d, Fig. 11, of the mandrel to reduce its cross-section, as a bag is pulled onto it. The member 10c has protuberances 10d which engage portion 43c of the elements 7d to cause this pivoting. When the bag is in position, the corner pieces are pivoted outwardly again by projections 8e on the jaws 9, engaging the portions 43c from the opposite side. When the transverse seam has been advanced by the jaws K, K<SP>1</SP> to a position adjacent the mandrel end, Fig. 5, this movement having been co-ordinated with the pulling of the previously formed bag of which the seam is a part,on to the mandre 17, members 31, 31<SP>1</SP> swing inwardly to cut the tube behind the seam and then outwardly. The jaws K, K<SP>1</SP> retract and suction is applied to the members 31, 31<SP>1</SP> ,  swung upwardly again so that in swinging outwardly, they open the cut end of the tube. An empty mandrel has meanwhile taken up position and its jaws 9, 9<SP>1</SP> move outwards to grip the opened tube. The jaws 9, 9<SP>1</SP> then retract as grippers H, H<SP>1</SP>, K, K<SP>1</SP> advance, their travel being less than that of the grippers to leave a surplus of tube for forming the bottom folds. The mandrel, after cutting behind the transverse seam has taken place, rotates to carry the bag past known means for forming the bottom folds. Each mandrel may have an axial tube 42 to allow escape of air during pulling on of the bags, and to permit pneumatic assistance in ejection of the finished bags.