Patent GB-623675-A (GB)
Title: Improvements in or relating to wrapping machines
IPC: B65B9/06
Filed: 1947-05-09
Abstract: 623,675. Wrapping-machines. ROBINSON WAXED PAPER CO., Ltd., NICHOLAS, F. P., NOBLE, F. W., and BAKER D. C. May 9, 1947, No.. 12665. [Class 94(i)] A wrapping - machine comprises a platform adapted to receive a paper web from a supply means, means for forming the web longitudinally into a tube, means for propelling an article along the platform into the tube, means For sealing the longitudinal edges of the web, means for forming two laterally opposed longitudinal reentrant folds in the tube, means for flattening the tube in lateral alignment with the re-entrant folds, means for sealing the flattened portions to each other, spacing and gripping means adapted to embrace the flattened portions and provide end abutments for two adjacent articles, and means for longitudinally moving the spacing and gripping means. In the construction shown, applied to the wrapping of articles of round cross-section, wrapping paper fed from a roll 13 is constrained into a tubular shape by passing under a forming wheel 17, over a platform 11 of arcuate crosssection and within a tubular mould 18. A carriage 52 mounted to run on rails 64 arranged forward of, and parallel with the axis of the platform 11, carries a pair of co-operating upper and lower gripper members 27, 28, Figs. 7 and 8, and a second similar pair of gripper members 25, 26 longitudinally spaced to the rear of the members 27, 28. The members of each pair of grippers are adapted for vertical upward and downward movement respectively from an inoperative position (broken lines, Fig. 7), to a gripping position. Sealing jaws 29, 30 which also embody tubesevering cutters 59 spaced axially between the pairs of grippers 27, 28 and 25, 26 are mounted for upward and downward movement respectively into a sealing- severing position. A pair of fingers 50, Fig. 8, are arranged to be movable relatively inwards horizontally so as to engage the sides of the paper tube which extends forwardly of the forward end of the mould 18 thereby to form laterally opposed reentrant folds in the tube. The gripper carriage 52 includes a package-receiving cradle composed of a series of lateral spaced longitudinal laths 53, and a package-stripper unit arranged forwardly of the carriage 52 comprises a series of laths 56 alternating transversely with the laths 53 and upwardly inclined to form a ramp. Articles to be wrapped which are adapted to be fed from a pack 62 on to the platform 11, are transferred to the platform 11 and are then propelled into the forward part of the tube within the mould 18 by a plunger unit 36 mounted on a carriage 31 which can move longitudinally on rails 35. The plunger 36 carries a head comprising an outer cylindrical shell 38 and an inner plunger 32 which is capable of being projected from the shell in a forward longitudinal direction. The plunger 32 carries a forwardly-projecting transverse rail 41 which is operable by the plunger 32 experiencing a pre-determined degree of forward resistance, to cause the closure of the circuit of a solenoid 42 carried by the plunger carriage 31, thereby to effect the engagement of a pawl 441 mounted on the carriage 31, with a rack 54 secured to the gripper carriage 52. The mould 18 is formed with a longitudinal slit on its upper surface having flanges 19 which engage the edges of the wrapper 12 and turn them over at 58 so that they lie flat on the surface of the package after being sealed by the pressing action of heated jaws 46 carried by pivoted arms 47. The plunger 38 is provided with air escape passages and when applied to packaging comminuted material or liquid this may be fed through the hollow plunger, the machine axis then being arranged vertical. OPERATION. - An article 39 to be wrapped, is fed on to the platform 11 and is projected forwardly by engagement by the plunger 32 in its extended position relative to the plunger shell 38, into the paper tube formed within the mould 18 and against the closure of the tube formed by operation of the fingers 50, grippers 25, 26, 27, 28 and vertical sealing jaws 29, 30 to complete the previously wrapped package 57. Engagement of the forward end of the article with the closed end of the tube and the closed grippers 25, 26 actuates the rail 41 and thus causes engagement of the pawl 44<SP>1</SP> with the rack 54 so that continued forward movement of the plungercarriage 31 is imparted to the gripper carriage 52. The wrapped package 57 which has previously been severed from the tube during the operation of the sealing-severing members 29, 30 is transferred by this forward movement from the cradle laths 53 to the stripper unit laths 56. As the tube is moving through the mould 18 its edges 21 in the flanges 19 are sealed by the jaws 46 which are brought into engagement at this stage. The pawl 44 is then disengaged from the rack 54, the grippers 25-28 opened and the gripper carriage 52 is retracted by means not shown, the article 39 being transferred from supports 61 on the carriage 52 on to the cradle 53 due to the maintained extension of the plunger carriage 31. The fingers 50 operate to produce laterally opposed re-entrant folds in the sides of the tube which form gussets between the top and bottom portions of the tube as they are turned over the rear end face of the article 39 and the forward end of the mould 18 by the action of the grippers 25-28. The distance between the rear end of the article 39 and the mould 18 has been determined by the degree of projection of the plunger 32 relative to the plunger shell 38, the travel of the plunger carriage being limited by engagement of the plunger shell with the forward end of the mould 18. The plunger carriage 31 then retracts into its rearward position prior to the forward projection of the next article 39.