Stage Rigging Spring 2015

Stage Rigging:

homework #3 recap:

Design Factor

Min. DF

static wire rope = 5

moving “running” wire rope = 8

fiber rope = 10

Last Week Recap:

knot= 50% efficient

WLL of rope x .5= WLL w/knot

THERE WAS A POP QUIZ!

Counterweight Rigging:

Single Purchase

http://www.ia470.com/primer/images/cntrwt.gif

top & bottom of arbor =purchase line

whenever a load is on the batten, you load that much on the counterweight arbor.

i.e. if arbor goes up 5′, the batten goes down 5′  Ratio= 1:1

Rope lock – only designed to hold 20-30 lbs of out of balance load.

*not designed to hold out of balanced load

(also rope lock is part of a longer system called lock rail.)

Loading Bridge= catwalk, where you go to load counterwreights to arbor.

-optional, but not all theaters (unfortunately) have them.

– common

*When there’s no loading bridge it’s shitty – very labor intensive

mid rail= jump floor

– there’s a pin rail so you can do spot rigging

– if something is out of balance, you can load a counterweight

– helps a lot of things go smoother,

Any weight above pipe weight = balance out the equipment

limit capacity of arbor = how tall it is.

Double Purchase:

https://wiki.vpa.mtu.edu/wiki/images/2/2b/Arbors.gif

(Similar to the Single Purchase system except the arbors are different, as seen in the picture above.)

-design to solve for a space problem

– you need half as much travel for arbor

1′ arbor = 2′ batten

1lb. batten = 2lbs. arbor

Drawback of Double Purchase = more weight = difficult to start.

Wire Rope – rope made of steel wire

In fiber rope – strands are twisted together

# of strands= how you designate wire rope

6 x 19 1WRC Aircraft Cable

where the 6 = # of strands

& with the 19 – the higher the # more flexible, and the lower the # the more durable

Fatigue Break – constant bending of less flexible the material resulting in breaking of the material

w/ pulleys:

Ratio: d/D, where d= diameter of cable, & D= diameter of sheave

d/D= 30+ = ratio for steel cable

Wire Rope:

Termination- how you attach it to something

1. Swage (Sleeve/Nico) Preferred

– copper sleeve down on the cable

-advantage= 100% efficient when done correctly

NOT ADJUSTABLE

also preferred = eye to eye/ jaw to jaw turn buckle, where the jaw to jaw removes shackle from system

Turn Buckle – made to adjust, in or out, one is right hand thread, & the other is left.

– used alongside wire rope

*Go/No Go Gauge*

NO ALUMINUM sleeve for overhead rigging

2. Crosbies/ Wire Rope Clip

-specified torque settings

-try to avoid because people are not aware of the correct methods needed when using them.

Advantage= ADJUSTABLE!!

– 80% efficiency

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