My wonderful wife often describes me as ‘Not a smart man, but he can lift heavy things’… Be that as it may, I am finding that as I get older, and the eyesight more blurry, all the things I am asked to move also get heavier. I am sure this has something to do with the increase in gravitational force as we fill the world with more useless noise, or something like that. But it has become apparent that I needed a better way of lifting heavy things.
For the really heavy stuff, I have the tractor. Old Lucie with the front end loader has routinely lifted very heavy objects for me, and since I replaced the hydraulic bypass valve and filter, it is performing exceptionally well.
But then there is everything else. I have plenty of bits and pieces in the shed, that are getting heavier year by year. And so I decided to do something about it.
My concept was that I needed something to lift around 150kg from the ground into the back of the ute. I also wanted something simple and low maintenance, with as few moving parts as possible. I initially looked at electric hoists, but quickly decided against them.
I settled on a simple mechanical pulley design. I had some old climbing rope, and figured with a couple of new blocks (pulleys), I could rig up a system that would allow me to lift heavy items such as generators into the back of the ute.
After being horrified at the quality of the blocks at a certain hardware store, I decided that the best option would be to buy some blocks from a place that specialises in such things. A yacht chandlery.
I put in a call to an old friend Ian who owns Franklin Marine down in Tasmania. Ian has years of experience sailing, including working on some beautiful tall ships, and has a background farming. He knew exactly what I wanted and sent me up a box of goodies in no time.
I had a great time running the line through the new blocks. Being stainless steel and designed for years of use in the harsh salt air, the blocks are excellent quality. With a becket on the single block, I was able to anchor the load line, effectively increasing my mechanical advantage. I welded a couple of gate hinges to the shed frame to form a cleat, and used an extra block to redirect the line. It was soon time to load test the new lifting hoist.
I asked the boys the million dollar question. If their combined weight is 120kg, how much effort do I need to put into pulling them skyward? The answers were wild and without reason.
From my memory, you simply add up the number of lines doing the work (not counting the line you are pulling). By counting three lines under load between the blocks, I should pull 3 metres of line to make the load move 1 metre. And if they weigh 120kg, then I will need to pull around 40kg to lift them up. Of course there is friction to take into consideration, and stretch of the line, which I usually add around 10% to, giving me a 44kg pull. The engineers in the family will be horrified by my rough assumptions, but I figure it is near enough for something you can work out at a glance.
If you’re interested in the load ratings.
- 2000kg – the 13mm kernmatle line
- 2000kg – the green strops
- 2000kg – the quality sailing blocks
- 450kg – the Mallion mounting the block to the rafters
- ?????? – the rafters!
Good job I figure the best I could lift is only a fraction of the system’s design – it would be a little embarrassing to pull the shed roof down on me!!
Special thanks to Ian at Franklin Marine for all his help and excellent products. You can find his details on their webpage here: Franklin Marine