| 摘要 |
A ribbon tensioning assembly includes a knob (44) having a top wall, an internal raised portion attached to the top wall (46) having a first helical camming surface and a second helical camming surface out of phase and disposed about a centre point. A compression helix (42) has a first end portion forming a first helical camming surface and a second helical camming surface for engaging first and second helical camming surfaces of the knob (44), compression helix (42) having a second end portion for receiving a spring (40). A clutch (36) engages a surface and connects to a spring (40). A spindle (12), attaching to a ribbon supply roll (64), secures the knob (44), the compression helix (42), the spring (40) and the clutch in relative position such that turning the spindle (12) causes frictional resistance between the clutch (36) and the surface for creating increased tension in a ribbon (66) dispensed from the supply roll.
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