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2 loading galleries - physics and safety Q

Discussion in 'Safety' started by Allana, Nov 4, 2018.

  1. Allana

    Allana Member

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    My theater has both an upper and lower loading gallery. On install, the JR Clancy rep told us to distribute 2/3 of the weights on the upper loading gallery and 1/3 on the lower. From a physics perspective, does this weight distribution actually effect whether the system is "in weight"?

    This 2/3rds process is physically harder on 1 loader than the other and takes more time. I'm wondering if the project can be split 50/50, knowing that something Very heavy would require more weight up top since the lower would run out of room.

    Secondly, how likely is it for someone on the lower loading gallery to be hit from a falling brick from the upper? Should they actually be loading one-at-a-time? That would slow this process down to an excruciating crawl.
     
  2. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Well, first question is the arbor a rod arbor with two sections - as in you can load top half and bottom half separately - or a brick house style arbor - with many sections? If the former, I'm guessing the empty pipe weight is already on the lower half, so 2/3 up and 1/3 down would average equal.

    Yes, I'd say the lower person should not be loading at the same time as the upper person. Clearing the rail here would mean clearing the lower loading bridge - but stepping toonstage side should be sufficient.

    Interesting- and not too common - issue. Very few theatres with double loading bridges.
     
  3. Allana

    Allana Member

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    The former - 2 sections. Pipe weight is distributed 2/3 - 1/3 as well.

    The flyrail is only 5 years old.
     
  4. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @Allana Idle chit chat: Is your venue's rigging system single or double purchase? I only ask because most of the times I've encountered dual loading floors they've been provided due to the appreciably longer length of double purchase arbors.
    Toodleoo!
    Ron Hebbard
     
  5. Allana

    Allana Member

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  6. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    THis is interesting. Other than the possibility the rep was just BS'ing you I don't know why 1/3 bottom 2/3 top would be recommended. But I'll find out - from the J R Wenger people or from someone here. The first reply I got did not suspect the two section arbor - but rather a front loader (AKA Brickhouse) - so a slight delay.

    PS - are the two sections equal length? Is there a middle guide in addition to top and bottom?
     
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  7. theatricalmatt

    theatricalmatt Active Member

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    I don't believe the Clancy rep was suggesting loading weight at the two different locations.

    I believe they were suggesting distributing the counterweight for the rail between the two locations, with 2/3rd of it at the upper loading gallery -- where you would normally be loading weight from, as that would put the batten all the way at deck and the arbor all the way at grid height -- and 1/3rd of it at the lower loading gallery, where it might be used on odd occasion (which I won't go into here). I would suggest also keeping a small portion of weight (perhaps one full and one half brick per lineset) at stage level, as they also end up being incredibly useful for there, and, no, not as doorstops.

    There is also a natural limit to how much weight the upper and lower loading gallery structures can take. They're usually pretty beefy, but it's worthwhile checking how much each floor can actually support and not overloading it.
     
  8. chausman

    chausman Chase Premium Member Fight Leukemia

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    That was my immediate interpretation. Simply where the unused weight was being stored, based on where it's more likely to be used.
     
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  9. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I assume with batten at low trim, both the top and bottom sectons of the atbor are at a trim where you can load from either bridge. 16' arbor and the bridges are 8' apart? My limited experience was 14' arbors and bridges 7' floor to floor. The exact alignment of arbor and loading bridges could be a part of the answer. If the bottom started at 2 or 3' above the lower bridge and the top section started at the bridge elevation.

    Hard one to answer without details of alignment and relationships.
     
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  10. Lextech

    Lextech Active Member

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    In the touring world it is common that when assembling large pieces that come off a truck that you put part one on the pipe and add weight accordingly. To add the bottom section fly out the first, attach the second and load from the lower gallery. That way you are in weight at each step. Having some weight on the lower gallery allows you to do this. Note that I have worked in theaters that had four or five levels that could be used to add or remove weight as needed, most of them having locks at each level so you could operate at different levels as needed. I have two loading galleries here and a crossover under the lower gallery. I have used all three to get something in weight as well as the operating rail and the floor. Easier to stay safe by not reaching out, climbing or doing some other silly stunt.
     
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  11. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Good points but on the hang top, raise, and hang botyom, why fill top half from top bridge first. Moving it part way and you couldn't reach bottom half.
     
  12. Smatticus

    Smatticus Active Member

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    We have two levels of loading gallery in a single purchase system. The middle gallery is a little more than 1/3 the way up the fly tower and we very rarely load weight from it. Occasionally if we are hauling something a bit out of balance we might position extra sets of hands on the middle gallery, but even that is relatively rare. We do the vast majority of our loading from the upper gallery and also from the stage floor. As stated by others, my reading of what the JR Clancy rep said is strictly about where stored counterweight is most likely to be used. If middle gallery loading is likely to be rare in your space maybe distribute more of the weight between the upper gallery and the stage floor with less on the middle gallery. The two-section rod-style arbor is interesting but I'm curious how much, if at all, that necessitates loading from the middle gallery vs the upper gallery? Can both sections be reached just fine at the upper gallery? Or, like Bill was wondering, do the sections align with the separate loading galleries? If that's the case what necessitates splitting the weight between the two sections? Is it bad if one of the arbor sections is empty?
     
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  13. Smatticus

    Smatticus Active Member

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    Bill, how would such a large separation between arbor sections work practically? I've never seen an arbor setup like this. Is it more common in double-purchase systems than single-purchase? It seems like it would severely limit the available travel distance.
     
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  14. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Im basing two galleries as in 7-8' apart anan a 14 to 16' arbor with a middle stop. Quite different from uour situstion. Maybe Allanas galleries are like yours middle and high vs high and higher. But she has two part arbors so i suspect it high and higher.
     
  15. TimMc

    TimMc Well-Known Member

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    We need good pictures of Allana's counterweight system and galleries.
     
  16. Allana

    Allana Member

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    I'll reply again tomorrow with space drawings.
    In short, baton "all the way in" gives you perfect access to both Upper and Lower Loading Galleries. You can load weights onto both without moving the baton. The Upper and Lower Galleries are approximately 10' apart (so ~60-70' above deck). If the arbor was max-loaded, the lower arbor would hold about half as many bricks as the upper (because upper-to-ceiling stop is taller than lower-to-upper stop). Loose stage weights were already distributed on both loading galleries before we were trained on the flyrail by Clancy. There is also a "Operating Gallery" that is about 35ft above the deck which is occasionally used for adding extra bricks (if something is half-flown out) as was mentioned by @Lextech . The lower shivs of the arbor are located below the stage deck (10-12' down), in the Arbor pit. All bricks are 18lbs.

    So my question is, can I load the bricks 50/50? Can I load 100% of the bricks from the upper?
    And what is the reason why I might not want to do either of those things?
     
  17. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I think the recommendation may have been based on the fact the lower section holds half as many. Simple equal distribution, proportional to capacity of each part.
     
  18. Allana

    Allana Member

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    Ok, so if I hear you right @BillConnerFASTC , there is no need to distribute 2/3, 1/3 except when nearing capacity?
    It's just that following the 2/3rds distribution, the loader on the upper does twice the work as the person on the lower. If they could split 50/50, it would be both faster and better from an ergonomics standpoint.
     
  19. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I think so but i wish i could hear from Clancy.
     
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  20. Allana

    Allana Member

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    See image for CAD drawing from architect.
     

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