| 摘要 |
A novel method and apparatus for feeding and tensioning a strap in a power strapping machine. The apparatus includes a strap feeding mechanism, a strap tensioning mechanism, and a pivoting roller carriage pivoted by a feeding and tensioning cam. The pivoting roller carriage first actuates the strap feeding mechanism to engage a portion of a strap and feed the strap toward a strap application assembly where the strap is formed in a loop about an object or group of objects. The strap feeding and tensioning mechanism actuates a first gripper that secures an end of the strap in the strap application assembly. The pivoting roller carriage then actuates the strap tensioning mechanism to engage a portion of the strap and apply a tension to the looped strap. The strap feeding and tensioning apparatus also actuates a second gripper that secures the tensioned strap in a closed loop about the package so that the strap application assembly may form a strap joint sealing the strap in the closed loop. In the event that the strap is not properly engaged by the first gripper, the strap will be fully retracted from the strap application assembly by the strap tensioning mechanism and the strap will be directed into a strap stretch-out housing where it will remain until the strap feeding mechanism again engages a portion of the strap and re-feeds the strap toward the strap application assembly. The weight and position of the strap disposed in the strap stretch-out housing prevents the strap from withdrawing entirely from the strap feeding mechanism thereby ensuring that the strap feeding mechanism will engage and re-feed the strap to the strap application assembly automatically. |
