Model : Parallel tangents
- Coil cords are formed by spirally wrapping cable around a metal mandrel. heating to a set temperature, and then reversing the coils to give the cord the necessary retractile memory.
RULERS OF RETRACTILE CORD
- Conductor stranding : # 36 AWG is the recommended stranding for most cords.
- Lay Direction : It yields a right hand retractile cord if cable lay is left hand.
- Tapes and binders : Decrease retractability of coild cords.
- Shields : In cases where shielding is necessary, aluminum tapes are recommended. If a strand metal shield must be used, spirally applied # 38 AWG strand is recommended.
- Thermoplastic materials : Polypropylene, Hytrel, Polyurthane are recommended at lower cost. Ther-moplastic retractile cords are susceptible to temperature. It will be lost its retractile form if exposed to temperature in excess of 120 F.
- Usable extension range : The extention ration in safety is half of used cable lenght. The extension ran-ge 10ft in length 20ft cable length to form retractile cord. Depending upon mentioned above some retractile cords will have verying usable extension ranges to wich a cord can be safely stretched and still retain its retracted form upon return.