GB785407A - Motor-driven machine for the purpose of tensioning and closing a loop applied about a packed article - Google Patents

Abstract

785,407. Tensioning bands. AKT.-GES. FUR TECHNISCHE NEUHEITEN. Dec. 16, 1955 No. 36196/55. Class 45. [Also in Groups XV, XXII and XXIV] In a machine for tensioning a loop about a package and comprising a motor driving a tensioning device by means of a clutch slipping at a predetermined tension and also driving a device for joining the ends of the loop, a clutch operable to complete the drive is provided in each of the drives for the tensioning and joining devices. A machine for strapping a package 99 is placed on the package by means of handles 97 and the overlapping parts of the loop are placed under a knurled tensioning wheel 31 and a die 62 for joining the ends of the loop. The tensioning wheel is pressed onto the strap by turning a handwheel 47. A lever 75 having a forked end engaging a groove in a sleeve 27 Fig. 4, is moved to engage dogs 29 on the sleeve with dogs 30 on the tensioning wheel, and the motor is started by turning a switch S. The motor drives a worm 15 to drive wheels 16, 17 driving the joining device and the tensioning wheel respectively. The wheel 17 rotates the outer member 18 of the slipping clutch the inner member 21 of which rotates concentric shafts 23, 37. The tensioning wheel is freely mounted on the shaft 23, and is engaged by a pawl 70. The sleeve 27 is rotated by the shaft 23 and is engaged by a pin 38 on the shaft 37. The clutch member 21 is pinned to the shaft 37 and slots 26 in the shaft 23 permit axial movement of the shaft 37. When the clutch slips, and the helical teeth of the member 21 ride over the helical teeth of the member 18, the resultant movement of the shaft 37 causing the dogs 29 to disengage from the dogs 30 so that the drive is removed from the tensioning wheel which is held by the pawl. If the tension of the loop is insufficient, the clutch is set to slip at another tension and the lever 75 is again rocked to reengage the dogs so that the tensioning wheel again tensions the loop. When a suitable tension is reached a lever 81 is rocked to engage dogs 52 on a sleeve 50 with dogs 53 on an eccentric 54 which operates the die 62. The sleeve 50 is rotatable with and axially slidable on the shaft of the wheel 16 so that operation of the lever 81 causes the eccentric to rotate and depress the die to deform the overlapping strap and a seal, if used, to join the ends of the loop. Rotation of the eccentric also causes gearing to switch off the motor. In the modification shown in Fig. 15 the dogs 29, 30 are dispensed with and the tensioning wheel 31 is fixed to the shaft 23. On axial movement of the shaft 37, resultant on the clutch slipping, a spring biased pin 152 moves so that a tapered part e on the pin engages a tapered part d in the shaft, the force of the spring being sufficient to move the shaft 37 so that the slip clutch is disengaged. In a further modification, Fig. 14 (not shown) a multiplate clutch replaces the toothed slip clutch and there is no automatic removal of the drive from the tensioning wheel as the clutch slips. In a machine for tensioning a wire loop about a package, the free end of the loop is engaged in a radial passage in a tensioning drum, and the eccentric is replaced by bevel gearing which drives a wire twisting device and shears for severing surplus wire from the loop. The levers 75, 81 which move the dogs, may be interlinked to ensure that one set of dogs is disengaged whilst the other set is engaged.