[TowerTalk] Ginpole for 20 foot sections

[Mike Gilmer - N2MG]

On Wed, 13 June 2001, n4kg@juno.com wrote:

> How is this 2:1 mechanical advantage achieved?
> 
> Scenario 1 -  End of rope is attached to the frame
> of the top pulley.  Rope runs down to Second pulley 
> with hook at load.  Rope then runs up and through
> the TOP pulley.  Force in each vertical run of the
> rope is 150 lbs.  450 lbs on top hook as proposed.
> 
> This is NOT how a gin pole is configured.  
> 
> In a block and tackle, one end of the pull rope 
> is attached to one of the pulleys.  The LOAD is
> attached to one of the end hooks.  Multiple
> pulleys can be mounted co-axially.  


Why is this NOT how a gin pole is configured? Even if one ties the fixed end of the rope to the tower (say when lifting a beam or rotator that need not rise above the tower top), one has not materially changed the configuration and still achieves 2:1 with a movable pulley at the load. BTDT.

A discussion that was, until recently, about the total load on a gin pole seems to have devolved into a semantical discussion of just what constitutes a "block and tackle" and the acceptable uses of a gin pole.

I've seen the term "block and tackle" used for various combinations of fixed and movable pulleys (when achieving some mechanical advantage).

73 Mike N2MG

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