Construct a lifting machine - middle years
One of the projects is to work as part of a team to construct a lifting machine. The lifting machine is to lift something (a load) that weighs at least 2kg and needs to be lifted to a height of at least 50cm by the machine.
To begin, here is some interesting information about lifting machines.
In our technological world there is often a need to lift or raise large loads to a particular height. A common example of this would be in the construction of a large building, where all the materials need to be lifted to the height at which they are to be used. In recent times large cranes have been designed and built to carry out this task.
Other lifting machines include jacks that can lift the weight of a car so the wheels can be changed or the car serviced, lifts in a city building that raise and lower people to and from the various floors of the building, and forklift trucks that can lift crates or pallets to the height at which they will be stored in a warehouse, or loaded onto a truck.
In lifting these loads, the lifting machine is raising the load against the force of gravity. These machines are all designed for convenience - they all need to be able to reach the position where the load is to be placed. For example, a crane used in constructing a building needs to be higher than the building itself, and a forklift needs to be able to reach up to the level where its load will be placed.
However, lifting machines are also designed to make it easier to raise the loads. They often use the principles of Simple Machines to do this. Many of them use pulley systems. These work on the principle of mechanical advantage, where a smaller effort can be used to raise a larger load. This effort needs to be applied for a greater distance for this to happen. For example, a crane motor might wind in 4m of cable in order to raise its load by 1m.
If you would like to construct a lifting machine as an EngQuest project, why not ask your teacher?