Improvements in or relating to apparatus for changing take-up rolls on a continuously running machine
957,847. Winding webs. CONSOLIDATED THERMOPLASTICS CO. Oct. 9, 1961 [Oct 10, 1960], No. 36167/61. Heading B6B. Winding web material from a continuously running source comprises winding the web on to a first roll, bringing a second empty roll into contact with the web intermediate the source and the first roll, wrapping the web between the first and second roll on to the second empty roll, displacing the first roll, and moving the second roll in the direction of travel of the web to the prior location of the first roll. In Fig. 1, a bag making machine 14, as described in Specification 957,848, carried a web winding mechanism 15 at the output end. An endless belt 18 runs round continuously driven heat sealing drum 17 and idler rolls 23 to 30. A web 32 of polyethylene film is fed on to the endless belt 18, and after processing, is fed to the winding mechanism 15. The web winding mechanism 15 includes a roll feed unit 35 storing empty rolls 96, a roll support mechanism 36, with a roll discharge ramp 37. The roller 27 over which the belt 18 passes rotates freely on a bearing 40 at each end thereof on a bearing 40 at each end thereof on a torque tube 41, Figs. 2 and 5. The torque tube 41 rotates in sleeve bearings 43 carried in frame members 44, 45 of the machine 14, and is driven by a motor 46 through a chain 48, and a gear 49 mounted on the tube. The roll support mechanism 36 includes two roll support units 53, 54 carried at the respective ends of the torque tube 41. The unit 53, Fig. 5, includes two vertical plates 55, 56 maintained in spaced relationship by lateral plates 57, 58, the vertical plate 55 being fixed to the torque tube 41 by welding. Two roll support arms 59,60 are slidably positioned between the plates 55, 56, Fig. 4, and carry gear racks 61, 63 engaging pinions 62, 64 respectively. The pinions 62, 64 are mounted on shafts 67, 69 respectively which extend the full length of the torque tube 41 and have similar pinions for support unit 54 mounted at the other end. Normally, the roll support mechanism is disposed horizontally, as shown in Fig. 1. An hydraulic cylinder 75, Fig. 2, is energized to urge the roll supported by arms 60 and 66 towards the belt 18 providing the driving torque for the roll. When the roll is full a finger 117 engages a switch 118, Fig. 4, and the motor 46 is energized to rotate the torque tube 41 through 90 degrees to the position of Fig. 10. An hydraulic cylinder 81 then urges support arms 59 and 65 upwards, thereby opening a gate 101 allowing an empty roll 96 to move into the roll receiving openings 111 of the support arms as shown in Fig. 11. The cylinder 81 then retracts the arms 59, 65, and when the empty roll engages the web the cylinder 75 is energized to extend the arms 60, 66 and move the full roll out of engagement with the belt 18. A source of air from a pipe-line 121 is directed along the belt 18 between the rolls to aid in forming a loop 120 and winding of the web on to the empty roll. This then tears the web, thereby freeing the full roll. The cycle is then completed by rotating the support mechanism through 90 degrees and retracting the support arms 60, 66. The roll receiving opening 11, Fig. 4, comprises a slot 112 communicating with spaced opposing semicircles 113, 114, fractionally greater in radius than roller bearings 99 carried at each end of a roll 96. A switch 115, Fig. 3 (not shown) operated by cams 111<SP>1</SP>, 1121, 1131, 114<SP>1</SP> mounted on torque tube 41, indicates the rotational position of the tube 41.