15b. Cable Control Variations
There are several modifications to increase dual control function
- Excursion amplifiers
- Nudge control unit
- Waist band
- Modifications to lift tab
| Excursion Amplifier
A pulley acts as a lever. With the fulcrum at f the moment exerted by F must equal the moment exert by W.[1] Remember – if you increase the efficiency of the excursion, you require twice the force to power the system
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Force amplifier used when ample excursion is available. 5 lbs of force will lift 10lbs of weight. While F travels 4 inches, W will travel only 2 inches. |
Excursion amplifier used when ample force is available. 5 lbs of force will lift only 2 ½ lbs of weight but F travels 2 inches while w travels 4 inches. |
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Nudge control unit
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Lever is coupled with a control cable so that pressure on it causes the cable to retract in its housing, and so trips the elbow lock.
Waist band
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| Modifications to lift tab
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- From Northwestern University upper limb prosthetic harnessing principles packet ↵