Grip Like a Gorilla

The ergonomics of loading counterweights place your hands at risk of being crushed and  banged about pretty badly.  You need to both protect your hands from outside abuse and to keep a good grip on those steel bricks lest you let one slip away and kill someone below.

Showa-Best Glove Company has a good solution to that problem.  Their S-Tex 300 and S-Tex 350 work gloves have rubber or nitrile palms for good grip, and they come in a safety neon yellow your buddy on the Loading Gallery doesn't forget where your hands are and plop a 20 pound brick down on one or both of them.

Showa-Best Glove S-Tex 300

Besides being bright and grippy, these gloves have a very high puncture resistance rating, tear resistance rating, and blade cut rating, so they can be very handy (forgive the pun) around the shop when handling glass, sheet metal, and replacing saw blades (NOTE:  never wear gloves when actually using a power saw or power drill - one snag and it'll pull your hand right into the blade or bit).  The open mesh back keeps your hands cool, too.

More info at:http://www.showabestglove.com/site/products/detail.aspx?style=S-TEX300 and http://www.showabestglove.com/site/products/detail.aspx?style=S-TEX350

Get a Grip

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

[Wire] Rope Terminations at Arbors

This picture shows a single purchase cast iron arbor top plate. The wire ropes are not supported by thimbles allowing them to deform and separate strands under load. Additionally, only one wire rope clip was used for termination, in lieu of the required minimum of two. Some of the "Crosby" clips (u-bolt cable clips) are installed backwards with the dead (unloaded) end of the cable run under the saddle (Remember: "Never saddle a dead horse").

The fiber hauling line does not have a thimble either, which acts to buffer the abrasive casting finish against the rope surface. Here is a picture of an arbor bottom plate with a plastic rope thimble (they are also available as a metal type):

This is a very old wire guided arbor with extended eye bolts for attachments (again, no thimbles to reduce the point-load on the rope bending point). You can also see that the top plate is tilted showing that the arbor has been racked and is skewed diagonally.

Here is the top of a double-width arbor (carries two stacks of weight). Again, no thimbles. It appears that the installer tied a clove hitch and then terminated the cable with just one wire rope clip. I don't know where the loose nut (partially hidden) that was laying on top of the arbor top plate came from . . .

And here is a the top of a new arbor that is properly terminated. Note that the load lines can be disconnected without cutting the cable. This makes them much easier to work on and replace if necessary. You can also see how the wire rope cables are not deformed as they bend around the thimble. Also of note is the safety wire (mousing) on the screw-pin shackle to keep it from coming apart. It's unknown why the front-most line was attached with a shackle when the other lines were looped around a through-bolt.

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!