| 摘要 |
A wire tensioning device for maintaining tension on a moving wire, especially a wire that is uncoiled over the axial end of a fixed spool of wire. The tensioning device includes a disk mounted at an axial end of a spool of wire. The disk has a plurality of radially extending resistant filaments that protrude beyond the periphery of the axial end of the spool of wire. The filaments engage the wire as it is unwound from the spool over the axial end thereof to apply a resistance to the uncoiling of the wire. A drive shaft powered by a reversible electric motor connects to the disk which motor rapidly responds to changes in resistance applied to the uncoiling wire by the bending or unbending of the filaments. An arm is engaged by the uncoiling wire. The arm is connected to a rotatably mounted axle for movement in a limited arc. A rotor is formed on the axle with the rotor having a lobe. A pair of proximity switches for operating the reversible electric motor in opposite directions of rotation are provided. One of the pair of proximity switches is positioned on each of diametrically located opposite sides of the rotor. The proximity switches are positioned relative to the rotor to locate the lobe in actuating proximity to only one of the pair of proximity switches during rotation of the axle in response to pivotal movement of the arm. An indicator arm is attached to the motor drive shaft and moves in an arc. Limit switches are located at the opposite ends of the arc to control the flow of electricity to the reversible motor.
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