Patent GB-807298-A (GB)
Title: Method and apparatus for closing open-mouth filled bags
IPC: B65B7/06
Filed: 1957-03-15
Abstract: 807,298. Closing filled bags. ST. REGIS PAPER CO. March 15, 1957 [March 31, 1956], No. 8567/57. Class 94(1). A machine for closing filled bags comprises means for moving a bag upwardly towards mechanism for folding down the sides of the bag mouth and means for detecting the distance between the folding mechanism and the surface of the contents of the bag and for arresting such upward movement when this distance reaches a predetermined value, so that subsequent operation of the folding-mechanism will cause the sides of the bag mouth to be folded at a position determined by the surface level of the contents. Filled bags are fed in succession over a driven rollerway 42, Figs. 3 and 5, and the leading bag engages a movable guide 45 and stop 46 to operate valves in the circuit of an air cylinder 49 whereby pressure-air is admitted to the righthand end of the cylinder to actuate a pusher 47 which moves the leading bag on to a plate 2, Figs. 3 and 4, supported by a hydraulic cylinder 5. Pressure-air is then caused to act on a piston 9 in a cylinder 6 to force oil through a pipe 7 controlled by a valve 8 into the cylinder 5 so that the plate 2 is elevated to position the bag mouth for engagement by the folding-mechanism. A casing 16 is carried by the rod 17 of a piston 18 in an air cylinder 19p and supports a spring-loaded plate 12 arranged to operate an air valve 15. The piston 18 is in its lowermost position when the bag mouth is moved upwardly through a guide 23, so that the casing 16 enters the bag mouth and the plate 12 engages the surface of the contents. The valve 15 is thus operated to cause the valve 8 to be moved to a closed position, so that the upward movement of the plate 2 is arrested. Pressure-air is then admitted below the piston 18 to raise the casing 16 and arms 19, 19a and 20 carrying knives 19b, 19ab and 20b are swung inwardly through linkage operated by an air cylinder 21 to form slits in the bag mouth defining the edges of closure flaps 31a, b, c and d, Fig. 1. The flaps are then folded down in succession to form the closure shown in Fig. 2 by reciprocating blades 25, 25a operated by pivoted air cylinders 29, 29a and reciprocating rollers 32, 32a operated by pivoted air cylinders 37, 37a. The blades 25, 25a are supported by rollers 26, 26a which are urged into engagement with guides 27, 27a by springs 291, 291a acting on the cylinders 29, 29a, and the cylinder 37, 37a are urged downwardly by springs 381, 381a. Glue is sprayed on the flaps by guns 39, 39a and 40. The valve 8 is then opened and the left-hand end of cylinder 6 vented to allow the plate 2 to descend to its initial position, and the closed bag is transferred from the plate 2 to a plate 54 by the delivery of the next bag to be closed, the plate 54 cooperating with a spring-loaded plate 55 to hold the flaps closed until the glue has set. The folding-mechanism is mounted on a superstructure la which is adjustable in height to suit bags of different sizes. The sequence of operations is controlled by a hydro-pneumatic circuit which is described in detail, each operation being controlled by a device responsive to the completion of a preceding operation. After a bag has been moved on to the plate 2, the movement of the next bag on the rollerway 42 is obstructed by a gate 44 which is moved across the rollerway by an air cylinder 44b and held in this position until the plate 2 returns to its lowered position. The pusher 47 includes a plate 47b which is operated by an air cylinder 47d to transfer the last bag of a series from the plate 2 to the plate 54.