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Mirror Ball Hoist System

Discussion in 'Special Effects' started by ship, Oct 30, 2004.

  1. ship

    ship Senior Team Emeritus Premium Member

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    Since rigging is gone, and this is sort of F/X, thought I might throw my current project out and see if it catches any more ideas:

    Ok, so my current project amongst many is pricing out some economical barr keep controlled means of lowering a 48" 120# mirror ball and motor from a club’s ceiling without the thing swinging or twisting all over the place. Bridling is not an option either.

    At first I thought a simple 3/16" wire rope winch would suffice to lower the mirror ball, but due to the size of the mirror ball thus start up twisting from the motor, my thoughts were that this system would need rotation resistant wire rope. Problem is besides a need to braze or weld the ends of it is that 19x7 wire rope requires a 6.3/8" D/d ratio or size of wire rope drum per type of wire rope used is 34 D/d. Given at best a 3" drum on a standard 3/16" wire rope winch, this might be a wee bit of a problem. More flexible rotation resistant wire ropes such as 35x7 with a 20 d/D ratio at 3.3/4" dia for the drum (Wire Rope User’s Manual) are not available in such a small size off the shelf it would seem.

    With wire rope, the more strands, the more flexible and rotation resistant wire rope it would seem is of need in this situation.

    So here is my question, what do rescue helicopters use for dropping a person down as far as hoist type and wire rope type given it’s compact size no doubt in being a maximum of stranding? How beyond belt lift or scissors lift which would be out of budget for the project would you approach such a problem of dropping than spinning a 120# mirror ball? Anyone know about helicopter rescue equipment?

    Furthermore, anyone have a web address much less accurate phone number to Mutual Hardware Corporation?


    I’m looking for pricing or advice for a resale install of a hoist system to drop a 120# 48" mirror ball in a club. Note that the drop length is expected to be about 10' but service length can be a minimum of 20'. Also that in starting the spin of the mirror ball, we are intending to stop spin by as much as possible which on our part could include weighting the motor further for ballast. This will be in a club install so power is expected to be 120v, power will be by way of plug for maintenance, and control will be conduit based either key pad or push button controlled at a remote location. (This is also preliminary as to the pricing out of a system thus details and other economical or better working ideas will be of use in figuring out what to do and the bid for it.)


    I’m taking it for a given we want 115v, Single Speed CM hoist given a chain hoist:
    #3801a 1/8 Ton CM-Techstar Chain Hoist, 32FPM, Limit Switches, 10' of chain, #2685P Rigid Lug for Plain low head trolley, & #2450 Metal Chain Container.
    #2702a 1/8 Ton CM-LodStar 1/4 HP Chain Hoist, 32FPM, Limit Switches, 10' of chain, #2788 Rigid Lug for use with single chain or low headroom kit, & #2450 Metal Chain Container, #2788 Non-Swivel Load Hook, 60LBS
    #3102a 1/8 Ton CM-LoadStar 1/4HP Chain Hoist, 16FPM, Limit Switches, 20' of chain, #2788 Rigid Lug for use with single chain or low headroom kit, & #2450 Stock Metal Chain Container, 68LBS
    #2401a/wb 1/4 Ton CM-ValuStar 1/4HP Chain Hoist, 16FPM, No-Limit Switches, 10' of chain is stock, Stock Snap Hook head, #2450 Stock Metal Chain container, 52LBS
    #2007 300# CM-ProStar 1/6HP Chain Hoist, 16FPM, No-Limit Switches stock, 10' of chain is stock, Stock Snap Hook head, #2010 Stock Chain Bag.
    #2000 300# CM-ShopStar1/6HP Chain Hoist, 16FPM, No-Limit Switches, 10' of chain is stock, Standard Snap Hook Head, 25LBS

    #2007SC Coffing ProStar 1/6HP Chain Hoist, 16FPM, No-Limit Switches, 10' of chain is stock, Non-Swivel, 26LBS
    #2040 Coffing Pro Star 1/6 HP Chain Hoist, 16FPM, No-Limit Switches, 20' of chain is stock, Non-Swivel, 28LBS


    Above Hoists, 115v/60Hz, NEMA 1 body. All will need permanent power supply and control set up.

    Another option is to go motor down to add ballast to the pendulum, but it would require a larger and second set of feeder cable to reel down. Not really recommended.



    Wire Rope Hoists - Advantages - four wire 5:1 rigging which helps to prevent torsion and as opposed to single line hoists, won’t require rotation resistant wire rope.
    CM has no Wire rope hoists under 1-Ton.
    PCM-Performer Tau Wire Rope Winch. Single line wire rope 330# Capacity, 0-16FPS, 105 feet or wire rope, 3/16" 19x7 Rotation Resistant Wire rope w. 10:1 Safety Factor,
    #BGO PCM-Beta Wire Rope Winch. Single Line wire rope Variable Capacity, Speed, & Lifting Height.
    #1140004, 125KG(187#), 16.73FPM, .25Kw Power, 3/16" Wire rope, 44#



    On wire rope for a standard single line wire rope aka-McMaster Carr winch:
    35x7 rotation resistant wire rope minimum stock size is ½" but will have a tighter bending radii.
    19x7 optimum size is 3/16" but minimum bending radius is 6.3/8" which would not fit on a standard 3/16" wire rope drum. Given this, what do rescue hoists use?
     
  2. Radman

    Radman Well-Known Member

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    Wouldn't a standard electric winch work if you simply ran 2 parallel wires about 40" or even less apart to 2 pulleys and into a single winch? Or am I way off in your problem. It seems like you need a way of lifting and lowering a mirror ball and motor without it twisting. The only tough part I see is getting the mirror motor powered, unless it didn't need to run when down or simply using an extension cord isn't a problem.
     
  3. ship

    ship Senior Team Emeritus Premium Member

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    No you are not way off but as with brideling, I'm told the amount of area is limited or I will have gone with two hoists. Good idea however, I was kind of thinking along the same lines at first also.

    As for powering, we do this all the time with moving lights and even mirror balls on scizzors lifts and chain hoists. I just don't think we have attempted a mirror ball this large from a single hoist. Basically the stock garage type cable reels or trouble light reels work well when re-rigged for stage use. Even transfers DMX for such types of mirror ball motor once the cord fed out is changed to data cable. Trick after re-rigging them so they are a little more heavy duty is in removing the stops so they are always under tension thus self retracting.

    I'm trying to avoid chain hoist but it might become the only option if I can't find a rotation resistant wire rope lift. Problem will be the single length of chain verses trying to get a 48" mirror ball rotating.

    Still the remote lifts and pulleys might be a good idea because than I won't have to worry about maximum fleet angles or a maximum height of the bridle though I might want to introduce some. Perhaps even a three point suspension given sufficient budget and the possibility of using a lesser wire rope gauge.

    Thanks, any more ideas out there?
     
  4. soundman

    soundman Well-Known Member

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    I think I might be just restating what Radman said but what if you had two pullys on the base of the motor than ran the wire like this:

    ! P------Hoist
    ! !
    ! !
    P-P

    Its late and I have a plot to finish so I might not be thinking right so please excuse the obvouse screw ups.
     
  5. ship

    ship Senior Team Emeritus Premium Member

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    I'm thinking along the lines of either above cheap chain hoists rigged to three 24" outrigger arms on the mirror ball motor mount to counteract sway, or three light duty wire rope hoists in either the center or along the edges rigged either direct or to head block shives going again to the outrigger arms.

    The outrigger arms would be key in preventing the center mounted mirror ball motor than from twisting and a three point suspension than will be best yet in preventing this. If I remotely mont a wire rope hoist by way of head block, I can cinch the mirror ball up pritty close to the ceiling also given I don't go chain hoist. The outrigger arm would also prevent the problems of fleet angle and maximum cinching up to the ceiling space needed at about 45 degrees.

    Even though a single hoist would be easier to control the speed of the wire rope coming out of it to be the same as opposed to three hoists all having slightly different speeds, I think out of symplicity and for the travel three individual hoists off the shelf will be simpler than rigging a drum to mount two or three wire ropes when designed for a single one given a very light duty hoist.


    Anyway, I'm thinking now about some 5/32" or smaller wire rope winches going either to head blocks or directly to three 24" spokes of arms off the mirror ball motor mount. This will give me 48" worth of prevention against it twisting too much as the mirror ball starts spinning.

    That's what I'm thinking so far having taken the head block idea in still going to a center point to the outrigger arms to have a direct vertical drop to the wire rope.

    m............m ----motor
    \............./ ----wire rope
    .o..........o ----head block
    ...<......> ----arm
    ........x ----ball center
    ........v ----arm
    ........o ----head block
    ........| ----wire rope
    .......m ----motor

    Side View
    m.....m.....m ----motor and head block
    |......|.......| ----wire rope
    ======== ----outrigger arm
    ........U ----mirror ball motor
    ........O ----mirror ball

    Hate it when what's a decent drawing by way of spaces gets condenced. Let's see if this works.
     
  6. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Ok – let me see if I understand this correctly:

    You want the mirror ball and motor to be able to be lowered whilst it is actually turning, not just for service purposes. Therefore, once the mirror ball motor is turned on, the inertia generated will cause it to twist on its suspending rope.

    Have you hooked up the ball and motor to a length of rope to see what the degree of twist would be?

    I am thinking of perhaps a steel plate with a short dampening arm attached to the motor to absorb the torque once the motor is started. I think that once the mirror ball is spinning, the twist shouldn’t affect the rope. It will be that initial momentum that is the problem (just hypothesising here – but also growing up around cranes as a kid).

    If the mirror ball is going to be turned on first and then lowered, you could make a dock at the maximum raise point. Lets say you attached the motor to a square plate of steel and then had a frame into which this sat when fully raised. When the motor turned on, the frame would prevent it turning on the rope. You could then lower it.

    I guess that this is going to be a trial and error thing and I would start by hanging it up it the workshop and turning it on.

    Hope that this is of some help
     
  7. ship

    ship Senior Team Emeritus Premium Member

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    “Have you hooked up the the ball and motor to a length of rope to see the degree of twist would be?” - Mayhem

    Ah’ excellent idea as I slap my forehead for being a idiot in something so obvious. Nope, did not try it. Granted at work I have huge amounts of other things to work on, but if I want to know what effect the mirror ball starting will have on a suspension, I should test it. Could be so slow, thus all my worries will be needless.

    At the moment and after talking with the sales person - other chief of tech in the shop - electronics department, we are thinking single wire rope hoist in a remote location. It’s single lineset than splicing out into three linesets than by way of head blocks going into a three point suspension above the mirror ball from about a 48" dia spacing from the center.

    Thus the three point suspension, but in what more you are saying I have a fresh idea I think you are hinging at. What if the primary lineset off the hoist still went to the center point of the mirror ball motor, and a second lineset was attached to this off a anti-sway lineset and single extension arm in preventing sway as the mirror ball started moving. This than being what is it a control line to direct a swinging piece of high rise steel into place but instead of it being manual, it attached to the main line. Given I’m already over 120# on the drop end, this single lineset off center should be sufficient to prevent start up twisting.

    Having a dock to start the spinning is also a good idea... I will have to bring these points up. My budget is now $500.00 thus three separate hoists is out of budget anyway.

    Key factor at this point is going to have to be with the club owner in either having a drop ceiling I can locate a remote hoist to in mounting, or at least some ceiling space some sort of horizontal fly system can be attached under neith.

    Thanks all, more to come I hope - this is practical problem solving many people should chime in on.
     
  8. Mayhem

    Mayhem Senior Team Emeritus Premium Member

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    Well that was my Science and Research background kicking in (as my theatre one is limited).

    The two options are to observe and answer "WHY" or speculate "WHY" and then prove it. Where ever possible - pick the first option.

    Sounds like a pretty cool project and I look forward to hearing more about it.
     
  9. ship

    ship Senior Team Emeritus Premium Member

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    So do I.
    At the moment, I'm in a holding pattern in waiting for the few remaining suppliers to get back to me on any products they might offer to solve the problem. Hate waiting for vendors to get off their rear. Wish either they would contact me back and say "sorry nothing I can do for you", or answer the question without me having to wait a few days or weeks as if I have the time to wait. Than a belated week or two later send me off a E-Mail in asking if their help so far is sufficient to land them the sale, or remind me of it in wondering if I wish to place an order.

    Most of my suppliers for any of these concepts have already bowed out given a small budget and less than high priced touring company needed gear to do the project. I respect that as long as they don't chase me around in a wild goose chase of constantly telling them, nope, read the directions of the request.

    One in not reading the letter I sent him explaining what I wanted to do and what gear I was looking for pricing given the budget, sent his own solution to the problem by way of two 1/4 Ton chain hoists and a 10' length of truss at about three times the price and a lot more shall we say reveal by way of a ten foot stick of truss sticking out in not following the design intent. Gee, yes this would solve the problem, but it's not in the least bit what I requested - not to mention none of the gear beyond the truss was within budget. My request was I do believe, do you have anything to offer within budget especially other than what is your normal touring products? At least he gave me a "good luck" after he was done helping me so I would know he was done helping me. Most others promiss to look into other options but never do.

    My own bitch as it were given for most of college I was a sales person for building materials in construction and I specialized in the oddball special orders and can only think of like twice in five years I had to tell a customer I could not find something for them to solve a problem. One instance was a key locking pocket door lock, the other was a tin ceiling just months before I finally found a supplier for them.

    Much in lost causes or special projects is my lot in life now, just wish the people that make their livings in being a sales person had the same ethics as I had in not only the customer being right but what ever they wished for I would go to the ends of the earth in finding for them.

    Anyway, for the moment, I'm working on other projects and will take back up this one next week.
     
  10. soundman

    soundman Well-Known Member

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    I hear that, if its at crew or at my real job, when people don't pull their weight it sucks. I can't do it is a pharse that should be replaced with could you help me or let me see if I can get someone to help me help you. I work at a grocery store and if someone asks me where something is and I tell them I don't know BAM I'm jobless, I'm supposed to ask a co-worker or maniger.
     
  11. OldGrover

    OldGrover Member

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    Ship,

    Just wondering something - from reading your posts, you are a tech guy at a rental/installation place, yes?

    That $500 budget you quoted - I'm assuming that that'd be for materials and that your own time would be charged to the client separately? Or do you eat this research time?

    Just curious - I used to do similar work in the computer field - cable pulling, network installs, etc - and I know we tended to eat the cost of our time for bid preps, etc.

    -OG
     
  12. ship

    ship Senior Team Emeritus Premium Member

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    Yes I do work at a rental/production/sales house. Preliminary problem solving and getting quotes time is fairly well eaten in my normal day’s pay no matter if it's for the company or a customer.

    I view my time as flux time (flexible or in the). Even when working on a specific project because I'm still answering questions or teaching how to with others in the shop, much less answering calls from the latest greatest supplier that want's to save me money.





    Thus in the end, I more view my day as I'm there and will be busy no matter if put to work on someone else's coin or the shop's. Given my back order for work done, the company gets a good value for my time no matter if I never work on stuff for the sales department or not. I thus don't much worry about who is paying for my time, I have so much to do that I just kind of just do what ever takes my interest or is most needed in the day.
     

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