pully system 4 -1 advantage needed for drum winch

Hi All

Can some one please help me.

I need to set up a drum wnich with a 4-1 advantage to the winchie;

winch load 1kg. load to be lifted 4 kg.

Now the hard part, the load lifting end of the cable can not be made fast to any other thing but the load

The load can not have a pully attached to it.

There cannot be a non-fixed pully between the last fixed pully and the load

I have gorgotten my phyisics and can't find the answer on the net

 

Situation is, I want to use a small 12 volt winch to lift a 4kg down rigger weight up and down and because of the depth of the weight using a pully fixed to the weight or "floating" is impracticale.

Any and all help appreciated


carnarvonite's picture

Posts: 8673

Date Joined: 24/07/07

Winch

Thu, 2011-10-06 15:51

Get a bigger winch or some dumbells to build your arms up

Posts: 9358

Date Joined: 21/02/08

Bit hard to see what you have

Thu, 2011-10-06 15:57

Bit hard to see what you have in mind without some scribbles.

Sounds like a 4:1 reduction gearbox, are you saying you want it to work like a capstan or a cray winch and not actually spool the line on to it?

Sounds tough!

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hlokk's picture

Posts: 4294

Date Joined: 04/04/08

Good ol gears! Or just a

Thu, 2011-10-06 17:53

Good ol gears! Or just a stronger motor/winch...

 

Bit confusing what you want otherwise. Keep in mind that if you want 4 times the force, you need 4 times the amount of line. Where does this line go? If you have a pulley contraption, it needs to shorten and lengthen to account for the extra line. E.g. if you want 10m of 'load' movement, then you're gonna need 40m of cable somewhere. Even if this is folded (as it is in a block and tackle setup) then it still needs to fit somewhere.

Posts: 4585

Date Joined: 01/02/10

How about a reduction gear on

Thu, 2011-10-06 18:01

How about a reduction gear on the cranking spool instead?

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Does anyone know where the love of god goes, when the waves turn the minutes to hours?

Posts: 93

Date Joined: 07/10/10

Yeah a bit hard to understand

Thu, 2011-10-06 19:44

Yeah a bit hard to understand what you want to set up. Basically has to be two anchorage points - If you're thinking of using sheaves or pulleys, you need to have 2 sets. You can terminate at either end but obviously the load would have to have a sheave set or pully on it. If you use pulleys or sheaves as a multiplier you'll need HEAPS more line, and it will reduce the weight seen by the winch, but will take FOREVER to winch up. For every purchase or fall, the winch will see half the weight. If you ask me this is not at all practical.

Simple one would be a bigger/longer handle for more leverage, or a smaller diamiter outrigger.