[SML] Automating Single-purchase

[Ben Thoron SML]

We automate our single purchase systems using both the standard winch,
just as Bruce suggests, and simply replace the handline with wire rope
and do the three to 4 wraps around a dedicated drum placed directly in
the space normally occupied by the floor block.

I can send picture if you email me.

Ben Thoron

bthoron at theoldglobe.org


On Tue, Jul 26, 2016 at 8:01 PM, Bruce Cooper via Stagecraft
<stagecraft at theatrical.net> wrote:
> On Tuesday, July 26, 2016 4:01:07 PM CDT, Ed Hills via Stagecraft wrote:
>>
>> Hello All-
>>
>> What would be the challenges, as you see them, in moving a single purchase
>> lineset off of a motor and a drum/mule/wench?
>>
>> It seems like such a simple idea.  Just replace the hemp with a longer
>> piece and take 3 or 4 wraps around the drum to move the line.
>>
>> Add steel, gear motor, and control.
>>
>> There must be pitfalls
>
>
> Slippage due to stretch or relaxation causing inaccurate encoder feedback.
> Tensioning problems due to same stretch/relaxation. /Wear on the [I assume
> 3-strand] operating line as it isn't allowed to twist and flex as it
> normally does to equalize the load on the strands.  Compression fatigue
> damage to non-3-strand ropes [most of the handlines in use today aren't
> intended to be run around metal drums].
>
>  I'd see about just attaching the end of a steel or proper synthetic winch
> line from the winch to the bottom of the arbor and leaving the system a
> little pipe-heavy.OR Alternatively getting a proper roll-on/roll-off
> automation winch and running to both top and bottom of the arbor IN PLACE of
> the handline.
>
> My thoughts only, but I would avoid using the handline at all in automating
> a lineset.
>
> :Bruce Cooper
> --
> Wandering Suntanned Stagehand.
>
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