Portable Turn Table Ideas?

[Chris Chapman]

Hey gang, I'm in the concept stage for a design for a small road show and wanted some input.

I'm thinking about a portable turntable that would be human powered (no motors) that has to be set up in less that a minute on a bare stage.

My idea is to have a center pivot platform (4'x4') with smart wheels and then the outside section lock onto it with either loose pin hinges or casket locks. The outside plats would have dumb wheels attached in the proper arcs to drive the turntable in a circle.

Do you think the dumb wheels will force the smart wheels into the same circle, or cause the entire turntable to drift or worse yet cause the smart wheels to lock and not be able to turn at all.

Thoughts?.....

Chris Chapman
Technical Director
Greenville Performing Arts Center

[Footer]

Originally Posted by Chris Chapman

Hey gang, I'm in the concept stage for a design for a small road show and wanted some input.
I'm thinking about a portable turntable that would be human powered (no motors) that has to be set up in less that a minute on a bare stage.
My idea is to have a center pivot platform (4'x4') with smart wheels and then the outside section lock onto it with either loose pin hinges or casket locks. The outside plats would have dumb wheels attached in the proper arcs to drive the turntable in a circle.
Do you think the dumb wheels will force the smart wheels into the same circle, or cause the entire turntable to drift or worse yet cause the smart wheels to lock and not be able to turn at all.
Thoughts?.....
Chris Chapman
Technical Director
Greenville Performing Arts Center

Well if there would be any way you could make some sort of friction pivot that would be the best option, but from the sounds of it you don't want a legit pivot (tell me if I'm wrong). Does this thing need to load in quick or does it need to come in and lock in durring a scene change?

[Van]

I'm going to post a turntable design that I have shared with a few others here. It sort of looks complicated, but when I was in college we used a turntable like this for ACTF when we had something like 45 minutes to load-in the set. It packs into a very small area, it will handle huge loads, and all matrials are readily available. Please forgive a few mistakes on the drafting I threw it into Acad really quickly and missed a few minor things I think. please feel free to give me feedback or ask questions as every bit of input will allow me to retune the drawing and be beneficial for everyone.
It's in Acad 14.

[Chris Chapman]

Yeah, it's for a REAL fast set up for a Theatre festival and I can't secure the pivot to any deck.

I haven't used a friction pivot before, how do they work? Is it just a pad tha comes down onto the deck like a lift jack and supports the load?

Hey Van, any way you can save that design as a PDF or othe file format? I'm still running MiniCad and can't import an Acad14 file. Can you save it as a previous version of Acad? Like (embarrassed) 11 or 12?

-Chris

[Van]

Sorry just checked back in on this, I'll have to post the pdf's on monday when I get back into the office. You should download the Autodesk veiwer however, it will let you print and view the versions you can't see now. The version of turntable I posted is designed for the center pivot to be screwed to the deck, however, you could use some rubber grippy stuff, you know the puffy rubber stuff you use on shelves to keep dishes from sliding around, <BTW This stuff works great for holding slippery wood pieces on a work table when using a sander or router> under it and it will work just as well.

[Van]

Ok ok here it comes kiddies, the pdf's, Now I know there are a few flubs in these as they cme off an earlier version of the acads I posted here , before I had a chance to correct them, but I think you'll get the idea. Wow I hope I got everything in there, just tried to upload the zip and hit the wall on file size. Anyway tell me if anything is missing feel free to contact me at my real email as I have unlimited File sizes there. Maybe I should ask Dave if the software here could be altered to accept DWG's as well ???

[Chris Chapman]

Thanks for the posting Van. Looks great. Sorry it took so long to get back to you, got buried in Tech and Running a show.

Anyway...

What is the advantage of the additional plywood raceway the casters run on in the decking? The last turn table I built had the casters running on the stage deck instead of on the bottom of the turntable deck.

Thanks again,

-Chris

[paul]

What show are you doing for One Act this year?

[Van]

Originally Posted by Chris Chapman

Thanks for the posting Van. Looks great. Sorry it took so long to get back to you, got buried in Tech and Running a show.

Anyway...

What is the advantage of the additional plywood raceway the casters run on in the decking? The last turn table I built had the casters running on the stage deck instead of on the bottom of the turntable deck.

Thanks again,

-Chris

No problem, I understand getting buried in techs.
The advantage of placing the casters "upside down", either through use of radial arms, like in the design I posted here, or by mounting them directly to the deck, is mostly for sound. I'm sure you are aware of woods ability to operate as an accoustic amplifier. Just as violins, guitars and Pianos use a wooden sound board, when you mount casters to the bottom of a platform <wagon> you turn the thing into a giant amplifier for every inconsistency in the floor. I have seen many things attempted to alleviate this problem, from mounting casters on springs to rubber washers, most simply don't work. They either make the caster wobbly < unstable> or do not affectively dampen the sound.
The plywood raceways on the underside of this turntable design also serveto hold it together. As this turntable was designed as a touring piece, we needed something that would pack into a very small space. Mounting the casters on the radial arms allows you to bundle them up with tie line and throw them on the top of a load, or in a corner. By not having the casters mounted to the plywood it allows you stack the "pie wedges" in a much smaller area without fear of knocking them off or damaging the casters themselves. Cost is also a factor here, you can get away with using a ton of smaller , lower quality caster with this design, rather than having to invest in a lot of larger, high quality, neoprene wheeled expensive, "quiet", casters.
The other real importnant aspect of this design is the use of Straight or Fixed casters and getting them aligned to the proper diameter on which they are running. By using fixed casters you eliminate the need for the casters to "swing" or rotate back to thier proper orientation when changing direction.
Ther ya go ! I gotta go paint a floor and hang some tricot.