What is a Chain Pulley?
A chain pulley is a simple mechanical tool to make the physical act of lifting objects much simpler. Consisting of a linked chain, a metal housing and several gears, a chain pulley uses physics and geometry to increase lifting efficiency. This tool is used in industries such as shipping and manufacturing and has been in operation for centuries in one form or another.
The chain pulley uses a variety of chain sizes depending on the job it is built to perform. Thinner chains are useful in jobs that require speed and do not involve lifting massive weights. Large, thick chains, conversely, take more effort to run through the chain pulley system, but they can withstand greater loads. Much thought is put into selecting the perfect type of chain to use in different situations.
A chain pulley housing is the most visible part of the mechanism, and it varies greatly in size. Constructed of durable metals, such as steel, the housing locks the gear wheels into place. They are constructed to withstand large amounts of pressure because the point where the housing is connected to a stable position, likely a ceiling beam or crane, must endure great amounts of strain.
The gear wheels within a chain pulley are what make this system function. Chain pulleys can have anywhere from one wheel to five in many cases. The simplest single wheel design has a chain feeding into the housing and over the wheel and out the other end. By pulling on one end, the chain lifts the object attached to the other end with greater ease than by manually lifting it.
Simple geometric and physical principles dictate that the more gear wheels added to the pulley system, the easier the lifting process. For this exact purpose, a chain can be fed around a housing containing several wheels. When the chain is pulled, each wheel absorbs part of the pressure from the weight and makes the act of lifting the object much easier.
The chain pulley likely has been in use since the time of the industrial revolution or even before, when technology first allowed for the creation of chain links. These tools still are used by industries that demand the ability to lift heavy loads, such as manufacturing or shipping. Also common in the modern use of chain pulleys is an automated electrical wench that does not require humans to do the pulling of the chain.
@minthybear19 - I have a small chain pulley. I got it from a friend for free since they stopped using it. At the time when I got it, I was just starting to build a rock wall.
I wanted to use big rocks in the design, but I couldn't move them -- so I started asking around for a pulley. I got the small chain pulley and it worked really great.
I had to hook it to the trees in my back yard -- but I got most of the rocks in! I had to skip a couple of the biggest rocks because the tree started creaking.
@tanner182 - You are right about safety -- I've had ropes snap when moving boards around. After that happened a few times, I decided to invest in a smaller sized chain pulley. I bought it new because the ones I looked at that were used had some rust on them. Someone forgot to oil them.
The chain pulley was fairly expensive but I don't like the idea of a bunch of boards crashing down on the people building below. I haven't had a chain break yet -- and I've moved some pretty big stuff. Hopefully, it never will.
@ElbowTickle - Sometimes it's worth it to pay the money and have something moved just to avoid a giant hassle. Chain pulleys are a great invention, but I've only ever used rope pulleys. I've never had anything big enough or heavy enough to need a chain.
A piano sounds like it would be dangerous to use a rope, so it's a good thing you had a chain on hand. They are expensive but worth it if you do a lot of moving or construction. My friend built a lot of his house on his own and he used a chain pulley to move some of the larger pieces around.
This brings back memories. My mom got a grand piano a few years ago and asked us to move it. Moving it would have been really expensive, but it was free to take otherwise. It's over a hundred years old and has been used in a church for a long time.
Anyway, we all offered to help -- the more people, the easier it would be! Or so we thought. Since this is a old piano, it was extremely heavy and big. We had to chain pulley it into the truck, which sagged to almost to the ground.
When we finally got it to my mom's house, we had to bolt a chain pulley to the roof beam and hoist the piano up onto the porch. It was a nightmare! We told her if she ever wanted it moved again, we would just take it apart into pieces first.
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