retractable stairs

[davidjmccollum]

hey all,
new user so please forgive any breach of protocol.

i need to build stairs that retract into a platform. the stairs will be 10" treads with a 9" rise numbering 7 so that the platform is at 6' high. they will start the scene retracted so that there is a vertical face to the platform. when needed they will extend out to form the staircase. no landing or turns neccesary. i just cant seem to figure out how to support the backside of each tread. budget and skillsets make lumber the preferred material over steel.

any suggestions would be appreciated. thanks

 

[randomtangentsrme]

See if you can alter these drawings/ designs to be applicable to your needs:
Patent US3157916 - LOCKING MECHANISM FOR COLLAPSIBLE BLEACHER - Google Patents
Patent US4363197 - Adjustable support rollaway bleacher - Google Patents

 

[Van]

Here are my questions in return;
1. What kind of budget?
2. How wide are the treads?
3. How wide is the Platform?
4 How Deep is the platfrom?
5. Will somone pull these out from the front or do they need to be pushed out from behind?
6 have you got a decent plastics supplier in town ?

 

[sharpcarp]

Off the top of my head I think the easiest way to support the stairs is quick to construct but uses more materials. I'd make them deeper than the 10" tread and have them sit on top of eachother. I'd use straight castors on the bottom one for sure and use either teflon glides or more castors on the stairs above depending on their width (weight). Here is a dinky littly drawing I made in paint to somewhat illustrate the concept.

 

[davidjmccollum]

The budget is small. Maybe 2-300 for this one piece. Maybe... the bleachers are a good lead but I can't figure out how the uprights nest unless each step is slightly narrower. They should all be 3' or so wide and the platform is 4' wide by 6' deep. Once I figure this side out I was hoping to do the same for a steeper escape stair on the up stage side. Offstage space is a premium in my theatre. Hoping that they are pushed out from behind but have 40+ chorus members so i could probably have someone pull them out.

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