spunky Posted June 7, 2005 Share Posted June 7, 2005 hello!! do the pullies of a counterweight system have to be in line with the cradle, or can they be diverted??? Link to comment Share on other sites More sharing options...
emj Posted June 7, 2005 Share Posted June 7, 2005 No they don't and yes you can Link to comment Share on other sites More sharing options...
gareth Posted June 7, 2005 Share Posted June 7, 2005 Just be aware of what you're fixing any diverter pulleys onto (can it take the load that will be applied?), and make sure you watch your fleet angles don't get too great. Link to comment Share on other sites More sharing options...
paulears Posted June 7, 2005 Share Posted June 7, 2005 Just had the engineers in to do tests on our c/w and winch systems and one thing they found in the grid was a few lines that had been diverted with poor fleet angles - the pattern worn in the pulley was interesting, with not much wall thickness left. One comment in the report was "the 6mm wire rope was terminated not by the usual practice of 3 approved type clamps, but by a clove hitch......." Link to comment Share on other sites More sharing options...
blackbird Posted June 7, 2005 Share Posted June 7, 2005 Feel free to tell me to google this one, but could someone explain to a non-flyman like me what a "fleet angle" is very quickly, purely as a matter of interest. Link to comment Share on other sites More sharing options...
paulears Posted June 7, 2005 Share Posted June 7, 2005 nope - that's a sensible question. The angle that the cable runs off the pulley should be at 90 degrees to the axis, i.e. parallel to the side faces. The design of the groove allows for some small movement away from this direction. Depending on the design of the pulley and the cable itself, 5 degrees is quite a lot, but acceptable in some designs. Much more than that and the sideways force increases and the bearings and flanges wear. There is also a greater chance of the cable slipping off if the line gets unweighted. in our theatre we have a door in the wall with the counterweight frames - so some of the fly bars are not level with the cradle that works it - basically in the grid a diverter pulley (or series of them) moves the flying lines accross to the right spot. In one of ours, it is only 6 inches or so out, and the people who installed it didn't bother with diverting it, just let the cables 'bend' a little too much before contact with the drop pulley. At the time, probably acceptable, but not today. Link to comment Share on other sites More sharing options...
emj Posted June 7, 2005 Share Posted June 7, 2005 The fleet angle is the angle witch a rope/line enters or exits a pulley. Link to comment Share on other sites More sharing options...
paulears Posted June 7, 2005 Share Posted June 7, 2005 I think I just said that Link to comment Share on other sites More sharing options...
emj Posted June 7, 2005 Share Posted June 7, 2005 You did I was typing and spell checking as you posted Link to comment Share on other sites More sharing options...
Chris Higgs Posted June 9, 2005 Share Posted June 9, 2005 BS 7906:1 recommends 1:40 (though primarily for wire ropes leaving drums), and I would suggest never less than 1:22 for pulleys.You can get some very neat sheave arrangements that may help from Halls, Flints and the more specialised companies like Stage Technologies.HTH Link to comment Share on other sites More sharing options...
andy_s Posted June 10, 2005 Share Posted June 10, 2005 Unusual Rigging are currently building our cw flying system which includes more bars than counterweight sets, with a very cunning diversion system so that we can fly above the thrust stage downstage of the pros when using the venue in that format by re attaching lines to counterweight sets upstage, and I've seen some pretty drastic diversion to fly up-and-down bars at side stage in some venues, so it's not that uncommon. Link to comment Share on other sites More sharing options...
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