If you have a heavy weight to lift without help, then you need a system of pulleys. A pulley system provides what is called "mechanical advantage," which means that it takes advantage of physics to make lifting easier. The pulleys of a pulley system are set up in a special way that transforms long low-power tugging on the rope into short high-power pulling on the weight you are lifting.
- Skill level:
- Moderately Easy
Things you need
- Pulleys with wooden frames
- Short length of rope, under 10 feet
- Screw hooks
- Plank of wood as long as half the pulleys laid end to end
Divide the weight that you want to lift by the amount of weight that you can lift. The resulting ratio is the mechanical advantage that your pulley system needs to allow you to lift the weight. Round the result off to the next highest whole multiple of two. In other words, you should aim for a two-to-one mechanical advantage, a four-to-one advantage, a six-to-one advantage and so on.
Screw one of the hooks into the wooden frame of one of the pulleys. Set it in as deep as you can. Repeat this process until half of the pulleys have hooks in one end.
Screw the wooden plank to the bottoms of the frames of the remaining pulleys, the ones with no hooks in them. Half of your pulleys should now be screwed to the plank, and the other half should have hooks.
Screw a hook into the middle of the plank. Place it on the opposite side to the pulleys.
Wrap the short rope around an overhead support and tie it in place. The support can be a lifting tripod, a tree branch, a beam or anything else capable of safely holding up the weight.
Attach the pulleys with the hooks to the support by slipping the hooks over the loops of rope. Place them near each other but do not let them touch.
Place the pulleys attached to the plank beneath the pulleys on the support. Thread the long rope through the first overhead pulley, down through the first plank pulley, up to the next overhead pulley, and so on in this fashion. Once the rope is threaded through all the pulleys, bring it up and tie it to the support overhead. The pulley system is now ready to operate. Attach the hook on the plank to the weight you want to lift, and pull on the free end of the rope to lift it.
Tips and warnings
- Be sure that the rope, the plank of wood and the pulleys that you are using can support the weight you need to lift without breaking.
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