Post Images, Resources and links about rigging on this thread
Just some images of handy rigging related things.
SLING PROTECTION
For the majority of museum rigging tasks that I have encountered my clear preference is for the use of round slings as opposed to the much more common flat style nylon straps.
Rather than expanding on all of the reasons for that right now I want to instead show you a nifty accessory that helps to minimize one of the few disadvantages this kind of sling has.
The heavy duty corner protectors shown above are magnetic and adhere pretty dang firmly to most ferrous metal surfaces. At my last job that frequently meant the forks of a variety of forklifts.
In that capacity they provide two valuable functions - they prevent damage to the inner polyester "yarns" that give this kind of equipment it's characteristic suppleness and strength also they restrict accidental movement on the fork.
These yarns are contained within a protective cover and should be inspected routinely by feeling them through the cover. Typically in a museum setting you will not be lifting objects that come close to the capacity of your equipment including your slings. That and the relatively infrequency of use mean that properly cared for your slings should last virtually indefinately. The one situation most likely to damage your equipment - having a heavy load focused on a sharp corner can be eliminated with these little gadgets. The secondary benefit of helping to prevent slippage of the slings going forward or backwards on your forks is created by both their shape and power of the magnets which are hard to move perpendicular to their attachment much less in a shearing motion. The use of these puppies as well as some attention to your tilt control means that you shouldn't need to put clamps on your forks.
Of course all not all sharp edges that you will be dealing with are going to be metal much less ferrous metal. In all of these other instances the "chap sleeves" shown above go over your slings or straps reinforcing them and redistributing pressure to help minimize or eliminate damage to the equipment. They are made of very thick Nylon and velcro right in place.
This strange thing is an adjustable rope sling.
When you are lifting objects that have irregular shapes with unknown weight distribution it can be difficult to determine the optimal "pick points" to result in a truly vertical lift.
After you do identify the best points the likelihood that the length of the slings that you have are going to provide a perfectly plumb lift are minimal. There are a few tricks that you can use to remedy the situation that hopefully someone will be adding to this section in the future. For example there is a method for configuring a standard sling in such a way as to make it adjustable. I have a diagram somewhere.......
I have tried this method and a bunch of other much more crude methods and they can work but by far and away the simplest and most direct way to facilitate the perfectly vertical lift that is required when you are placing a "pinned" sculpture is to have a tool that is made to order.
The way this thing works is ingenious and may very well take you back to your gradeschool days. Do you remember those little things that you could put - on one finger of each hand (in my day they were called chinese handcuffs - where this came from I have no idea) and the harder you pull the stronger they gripped each finger?
The same concept is in play here. In the illustration you can see how the rope on half of the loop fits inside of the other. As pressure is applied the outer rope clamps down on the inner. The clamping action is proportional to the load placed on the rope. adj sling with co.jpg
Here we see the business end of this tool with the cover in place over about 10 inches of "the works".
Now we all like to think that we are at least somewhat up on the tools of our trade, but I don't mind admitting that this was a new one on me!
I've tried it and it works like a charm. The 1/2" light weight version is rated at 1,600 pounds on a choke, 2,000 pounds on a vertical lift and 4,000 pounds on a basket lift.
There are two basic types and a variety of sizes and capacities. To good to be true?
I personally think it is healthy to be sceptical about these kinds of things but in this case the source is a company called Lift-It and they are highly reputable by my estimation. They also carry the other two accessories shown above. Anyway go to their website if you are curious.
Who is going to send a picture of an adjustable configuration on a standard sling anyway?
I just had a thought. For those of you who attended the SFMOMA handling workshop in November - the adjustable sling in the picture above is the same type that Kevin Marshall was showing off after his moving large objects talk.
best
ashley
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