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Slack in rope

Discussion in 'Scenery, Props, and Rigging' started by photoatdv, Jun 21, 2008.

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  1. photoatdv

    photoatdv Active Member

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    Does anyone know why there would be slack in the purchase line of a counterweight lineset? There is only one that I've ever noticed this problem with- the main curtain. I think it happened amidst a near disaster where main and valence fouled and we had several near runaways where all 4 of us had to grab the rope. Somewhere in the middle of this it suddenly went slack- the floor block moved up, and I thought it went back down, but I guess not all the way...

    Is this anything to worry about? Based on my experiece/ basic knowledge of the flysystem setup it doesn't seem like there could be a real problem-- but I thought I'd ask to be sure.

    How do I fix this? Feel free to PM me on this one if you don't want to post it-- Though I'm thinking this falls under normal use and maintnance and is okay.
     
  2. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    The primary purpose of a floating floor block is to account for rope length changes due to humidity. Is this a hemp line? Have all the rigging, particularly the knots, inspected by a professional.

    Be safe, rig right!
     
  3. photoatdv

    photoatdv Active Member

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    No it's counterweight-

    "why there would be slack in the purchase line of a counterweight lineset"

    The only knots on our flies are on the purchase line.


    I guess I wasn't very clear- I know the problem is with the floor block b/c I know it can go lower. The real question I guess is why is the floor block not providing tension.
     
  4. Charc

    Charc Well-Known Member

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    Spring popped loose on your near runaway?
     
  5. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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  6. photoatdv

    photoatdv Active Member

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    Charc- Don't know what you are talking about :). I've never done anything with the floor blocks and I guess don't really understand how they work beyond providing tension.

    Derek- -Sorry, I *think* the purchase line is some type of synthetic. I don't have any specs for it to tell you exactally

    - What is the difference between a kick block and gravity? My assumption was that gravity pulls down the block providing tension, but I may be wrong.

    - The track is the kind where the back of the arbor fits between two metal pieces which are attached to the wall. (I'm thinking that is T- track but please enlighten me on the diferences)
     
  7. Charc

    Charc Well-Known Member

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    I don't know what's going on either, I can't follow threads at neigh 4AM, I just threw that out there, I should turn in.
     
  8. photoatdv

    photoatdv Active Member

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    True we probably shouldn't be trying to figure out rigging in the wee hours of the morning.
     
  9. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    The questions Derek is asking are to determine if your rope has stretched or if your tensioning system is not working correctly. Those are the two ways you can develop this problem.

    You need to have your system inspected and get some training. You should not be having "several" near runaways. People get KILLED with runaways. Did you hear me? KILLED as in DEAD. If you have had "several" near runaways either there are major problems with your system that need immediate repair before it is used again or your crew does not know how to safely operate your system and you all need training before you use it again. Either way you need a full inspection with training. You should NEVER get in a situation where 4 people have to grab a rope... that's EXTREMELY dangerous... another member here has told the story several times about the tech who ripped the skin off his hand doing that.

    I don't mean to insult you with this post, but your questions show you do not know what you are doing. People who don't know what they are doing have no business running a fly system. It's the by far the most dangerous thing in tech theater. If you walked up to the dimmer rack and saw a bunch of big fat bare wires you would say... hmm that's dangerous I better not touch it. Well when you fly things you are not just endangering yourself but everyone around you as well. Get some training and a service call to inspect and repair your system before someone gets killed... until then Don't Touch!
     
    Last edited: Jun 21, 2008
  10. photoatdv

    photoatdv Active Member

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    Gaff,
    The reason that we had the near runaways was because the two fouled essintially creating a dynamic load as the weight shifted between the two battons. I might have exagerated about several there were really just 2 times we nearly lost them-- before we realized they fouled. We were a lot more careful once we realized there was a problem.

    We(by we I mean the student-professionals and professionals-- I've yelled at junior crew enough times for that) NEVER leave a lineset out of weight enough that it takes more than one person to handle.
     
  11. Footer

    Footer Senior Team Senior Team Premium Member

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    Explain fouled....

    Get someone in there who is qualified to figure out what is actually going on.
     
  12. photoatdv

    photoatdv Active Member

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    By fouled I mean caught-- The bottom edge of the main got caught on the pipe for valence. We simply flew main all the way out and valence in and it fixed the problem. I think I know when the thing with the tension pulley happened. The teacher was pulling down on the purchase line on main and I was raising valence, I reached with one hand to help him because he was having trouble and grapped the rear line. At that point the tension pulley slid up and we were suddenly holding lots of slack. The slack allowed more of the weight of main to rest on valence, throwing it out of balence. I let go of main and grapped valence and the two other techs grapped main and helped the teacher hold it. I saw the tension pulley go back down, however I don't think it went all the way back down.

    I did not notice that there was still some slack until a few weeks later.
    I did try gently pushing down on the tension pulley which did nothing. Have not tried anything else. If anybody has advice that they can't post, PM me and I'll give you an email.
     
  13. TechSooth

    TechSooth Member

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    Normally the lower (floor) sheave floats in the same track as the guide for the arbor. Its purpose is to remove slack as stated before. Check to see of the sheave block moves freely up and down by grasping both lines and lifting. It's heavy, but it should slide in the track.

    If the sheave mountings become jammed and the sheave will not move up and down freely, a swift upward kick to the front of the sheave mounting frame can usually loosen it and allow it to fall back down. It may even require the use of a wooden mallet.

    If not, see if you can figure out why it doesn't slide. Could be that the track got bent or one of the guides attached to the block is twisted. When things start moving, the forces involved can easily misshape the guide rails, but my guess is it's just jammed.

    If you cannot free the block, professional maintenance is called for.
     
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