Arbor Day - The Last Friday Before May!

Annual  -- To do something EVERY year.  Rigging Inspections should come to mind, and although 'Arbor Day' is intended to be the day we all plant a tree, or three, it should also be a reminder that the counterweight carriages (aka: 'Arbors') in our stage rigging need love, too.

We want to look over your equipment and make sure that everything is in proper order.

• Nuts are tight.  The top and bottom rod nuts should both be checked to ensure that they are properly clamping the top and bottom arbor frames.
• The rods and back-bone are straight.
• Each cable and rope is properly secured.
• The guide shoes are clean and properly fitted to the guide rails.
• Spreader plates are spaced-along the length of the weight stack and not buried at the bottom.
• Weight locks are present, and have screws in them to allow them to be tightened-down so they can hold the counterweights from jumping out of the arbor frame in the event of a run-away and crash.
• Take the time to enumerate the arbors so they are easily identifiable regardless of what level they are positioned.
• Check to see if anyone has maybe added extraneous weights to the system . . .
There are many more things to check as a part of the rigging system, so this wasn't a complete list.

Remember: People are the most dangerous things in the theatre, so make sure that each person using the rigging system understands how to handle the weights, are secure so they can't fall over the weight loading railing, and they fully understand about using spreader plates, rope locks, and weight locking collars.  Using the tools you have properly can save lives!

KEEP THOSE ARBORS BALANCED (also referred to as: "In weight").  Train your crews to pace their work so that the fly crew (loading bridge crew) can keep-up with the ground crew that may be loading or striping a batten.  Out of balance systems can lead to run-aways, and that can really rack-up a system:

You can Huff and Puff, but you won't blow down this Brickhouse

Say what you will about counterweight rigging being medieval, it still goes into a lot of stages and is used every day by many people.  So, if you're going to do it, you might as well make it safer.  At USITT 2010 in Kanasas City, Thern Stage Equipment Company introduced the "Brickhouse Front-Loading Counterweight Arbor System".  This takes a whole new approach at how you handle the counterwights as they are loaded and unloaded, and also takes a new look at securing them in the arbor carraige.

The first thing one notices it that the Brickhouse has side walls and three compartments for counterweights.  This allows you to load weights into the most convenient compartment to access, rather than reaching high or low and possibly overextending oneself.

The next convenience is that as you place weights in the Brickhouse, you don't need two hands to do it.  No awkward twisting, tilting, or finagling of the weights to get them in-between the arbor rods.  Why?  Well, there is no back rod, and the front rod conveniently swings out of the way so you can just slide the weight 'bricks' into the compartment, which is sloped a bit to help with the process.

The weights have a handle built right into them, too.  What a concept:  A counterweight that you can grab onto with one hand and hold it securely without fear of dropping it.  This leaves your other hand free to hang-on for dear life (you are wearing a fall prevention / arrest system as you load weights, right?)

Once the weights are nestled into their compartments (and you can fill the compartments all the way to the top, too), you just swing the front arbor rod back into place and let 'er fly.

Drop testing shows that a stage heavy line set will crash throught the lower arbor stop just like a regular arbor (no surprise there), however, the side walls are built to take a lickin'-and-keep-on-tickin', so you shouldn't have a mess of bricks jumping out of the Brickhouse.  No word yet on the potential for bricks jumping out of the Brickhouse in the event of a stage-heavy run-away, but given the design of the compartments, it looks like the weight-lock free design still keeps them under control and not raining-down a hail storm of steel plates on the fly crew should a line set get away from you.  That said, I'm still wearing my hard hat PPE when I'm onstage or in the fly galleries - there are still a lot of other hazards out there to ping your skull.

More info can be had at: http://www.thernstage.com/products/rigging-systems/counterweight-systems.html

Round and round we go . . .

Occasionally we'll run into these in really old facilities. Although quaint and historic, they are really dangerous. These are round counterweights. Note that there is no top clamp, and nothing to keep them from sliding off of the center rod. They really belong in a stage equipment museum display, not on a stage.

Weight, weight, don't tell me...

Why is it that EVERY rigging system I see has loose, missing, or missapplied weight locking collars? These are the easiest thing in the world to use! My advice: Check, check, and re-check. If your fly crew won't use them, dismiss them from the fly rail.

The weight lock collars at the left are 3-4 feet above the top counterweight, and the ones on the right are probably 15-18" up.

That won't keep the counterweights in-place should you have a stage-heavy run-away. The arbor hits the top stop and inertia lets them keep on going . . . until gravity overcomes the flight pattern and it comes crashing down to the floor below; probably bouncing and boinging off of the adjacent metal, rope, and cables all along the way. Talk about an uncontrolled and unpredictable ballistic missile!

Here is what can happen when the weight hits the floor:

The force of the impact broke-off a 2" thick piece of steel! Imagine what would happen if it struck someone on the way down! Even an OSHA required ANSI standard hard-hat wouldn't help you.

Of course, stacking the weights on top of the weight locking rings won't help either . . .

So what else could we do wrong? How about no thumb-screws in the locking collar . . .

Or maybe use a U-Bolt to clamp the weights in place (note the rear clamp has slid down into the back fork of the weight).

Counterweight Locking Collars.

Use 'em!