But this is not, apparently, what N4KG is saying...
The kicker is, in your words, "plus down force it takes to hold the load static
at the workers end of the load line".
In a system with mechanical advantage, this worker-applied down force has been
reduced - that's the whole idea! When this down force has been reduced, it
reduces the total load on the gin pole.
73 Mike N2MG
On Wed, 13 June 2001, "Paul Finch" wrote:
> So the weight exhibited to the Gin pole at the top
> pulley mount point is the down force of the load
> line plus down force it takes to hold the load static
> at the workers end of the load line? No matter how
> many times the advantage. Right?
> Paul Finch
> -----Original Message-----
> From: email@example.com
> [mailto:firstname.lastname@example.org]On Behalf Of email@example.com
> Sent: Wednesday, June 13, 2001 1:46 PM
> To: TOWERTALK@contesting.com
> Subject: Re: [TowerTalk] Ginpole for 20 foot sections
> More N4KG observations and comments inserted below.
> On Wed, 13 Jun 2001 12:18:30 -0400 "Guy Olinger, K2AV"
> <firstname.lastname@example.org> writes:
> > The reduction mechanism of a ganged pulley system is in the number of
> > feet of rope the worker pulls in as a ratio to the distance the load
> > travels. In a two to one system the worker pulls 200 feet of rope to
> > lift the object 100 feet, thus the analog to a lever, and the
> > advantage.
> The distance traveled is a RESULT of the mechanical
> advantage, NOT the CAUSE, but can be used to calculate
> the mechanical advantage. N4KG
> > Two to one: rope tied at top block, through pulley at bottom block,
> > through pulley at top block, to worker.
> > Three to one: rope tied at bottom block, through pulley at top
> > block, through pulley at bottom block, through pulley at top block,
> > to worker.
> > Four to one: rope tied at top block, through pulley at bottom block,
> > through pulley at top block, through pulley at bottom block, through
> > pulley at top block, to worker.
> > 73
> Note the presense of MULTIPLE pulleys at the top
> of the block and tackle. A GIN pole has only ONE
> pulley at the top. The only way to get a mechanical
> advantage is to use a SEPARATE block and tackle
> with a SECOND ROPE. As I said before, this helps
> the puller but does nothing to reduce the load on the
> GIN Pole. de Tom N4KG
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