Patent GB-778315-A (GB)
Title: Improvements in or relating to machines for strapping or girdling bales, packages orthe like by means of a metal strip
IPC: B65B13/22
Filed: 1954-12-17
Abstract: 778,315. Tensioning bands. SOC. ar. 1. AUCEMO. Dec. 17, 1954 [May 17, 1954], No. 36567 /54. Class 45. [Also in Groups XV and XXIV] In a power driven machine for banding packages with metal strip comprising a package supporting plate, means for feeding the strip to the package and for withdrawing surplus strip from the band, means for feeding seals for joining the ends of the band, and a sealing device, the tension of the band is regulated by means of a dashpot. Strip 7 from a reel 6 is led between toothed rollers 20, 23, along a passage 26, under a member 35, and through a slot in the supporting plate 2. The roller 23 is mounted on an eccentric shaft 24 having a lever 27 urged by a spring 28 so that the rollers grip the strip. A treadle 31 is depressed to move one arm of a bell-crank 29 from beneath the lever 27 and to close a switch starting a motor 5 so that the rollers feed the strip to the package resting on the supporting plate. After being passed by hand around. the package the end of the strip is threaded between the member 35 and a knurled tensioning wheel 52. The treadle is released and a second treadle is depressed to reverse the motor and drive the rollers in the reverse direction to remove surplus strip from the band. Depression of the second treadle drives a sleeve 40, Fig. 5, connected to a pulley 37 by ratchet gear, to rotate the tensioning wheel by means of a drive comprising gears 44, 45, a slip clutch 46, 48, and gears 49, 50. A latch 63, Fig. 6, is released, by the depression of the second treadle, from a notch 64 in a sector 65 which rotates until the notch engages a cam 68 on a shaft 34, the sector being connected by a link 69 to a lever 70 keyed to the eccentric shaft 51 on which the tensioning wheel is mounted so that the tensioning wheel rotates and exerts a slight pressure on the overlapping strip beneath the member 35 when the rollers start their reverse movement. The movement imparted to the strip by the rollers is faster than the peripheral speed of the tensioning wheel and the resultant torque on the wheel causes the axially movable part 46 of the clutch and a shaft 47 to move to the left, Fig. 5. The movement of the shaft turns the shaft 34 and is resisted by the dashpot 15. At the beginning of the movement of the part 46 a cam 33 on the shaft 34 lifts a lever 32 to separate the rollers, and the cam 68 frees itself from the notch 64 so that the sector rotates to force the tensioning wheel against the strip. Continued rotation of the tensioning wheel tensions the strip about the package until the clutch slips at a strip tension determined by the setting of a handwheel 117 controlling the resistance of the dashpot. Towards the end of the leftward movement of the shaft 47 a cam on the shaft 34 moves a spring returned push rod 73 to the left so that the pulley turns a crankshaft 80 for one revolution. Sealing strip 11 having a central row of perforations and supplied from a reel 10 is led over a guide 89 to a tool 14. One of the perforations is engaged by a projection 88 on a lever 84 which is oscillated by a cam 81 on the crankshaft to feed strip into the tool. Rotation of the crankshaft also operates the tool to sever a seal from the strip 11, to sever the strip 7 from the band, and to close the seal about the ends of the band. At the end of the revolution of the crankshaft a cam 101 engages the lever 70 to set the tensioning mechanism in its initial position.