| 摘要 |
A supply of wrapping material for a wrapping mechanism is provided in the form of a spool having a core member which is rotatably mounted to the lower ends of a pair of support arms having their upper ends vertically pivotally mounted to an arm support for pivoting about a horizontal axis. An upright contact surface is located below the horizontal axis and is engaged by one side of the spool of material such that the surface offers frictional resistance to the unwrapping of material from the spool. In order to keep this frictional resistance substantially constant through out the unwrapping of material from and consequent loss of weight of the spool, a biasing spring may be connected between the arm support and at least one of the arms and/or the surface can be configured or coated with frictional material such that the coefficient of friction of the surface increases in a direction away from the horizontal axis, this being the direction that the zone of contact between the spool and the surface travels as wrapping material is pulled from the spool during wrapping operation.
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