Cranes

Cranes

 * A lifting machine that can be used to lift and lower heavy materials
 * Uses multiple simple machines to make a mechanical advantage. This allows it to move loads beyond the human capacity.
 * Used for construction and transportation
 * Construction
 * moves heavy materials
 * Transportation
 * used for the loading and unloading of frights
 * First used by the Ancient Greeks
 * Simple Machines
 * lever
 * pulley
 * Two important issues when thinking about your crane
 * must be able to lift a specific wight
 * must b able to lift the weight without loosing stability
 * sum of all moments must equal zero to maintain stability
 * Cranes Consist of these important parts.
 * base-attached to a large heavy pad, that supports the crane
 * tower- gives crane it's height
 * slewing unit- this is the gear and the motor, it allows the crane to rotate
 * On the slewing unit there are three parts
 * jib- carries the load
 * machinery arm- holds the motor and electronics. It also holds the counter weight
 * Operator Cab- this is where the operator sits
 * The closer the weight is positioned to the mass the more weight it can hold

OUR PLAN

 * get some Popsicle sticks
 * Build the base out of board
 * Build the support beams with the cross sections
 * make some arch cable supports
 * put in the engine at the base
 * set up the pulleys
 * call it starfish

So far the crane project has had some up and downs. The building of the tower was pretty straight forward. Making it all come together on the other hand is a lot more difficult. We bought our own 6 volt batteries so that we could put them into the support system. We have one battery positioned at the back of the crane in a box. This adds weight holding the crane back. We then built a tower up off of the box. From that tower we ran fishing line to the slanted tower. This will give it support when it is lifting objects. We then used the other battery as a wedge for the slanted tower. For additional support we [placed eye hooks on both side of the battery box and ran fishing line down to them. The gear box was also a major pain. I could not figure out how to slow down the motor, so I will just have to be careful when apply the alligator clamps on to it. The only way I could think of slowing the motor down would be to get a very big gear and put it between the motor and the main gear. Too bad Lowes doesn't sell such a thing and I could not find one in school. I used two pulleys for the lifting. One was right at the top and the other is at the bottom and it will attach to the object. I used leather thread for my rope. For all of my problems the outcome turned out pretty well. I just hope it preforms as well as it looks. Below there are pictures of the crane in construction and the finished project.