Tower Crane Project

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					2/1/2010                                                                   Baltimore Polytechnic Institute   Engineer




                   Tower Crane Project
                                              (Model)
Goals:

        Students will learn about simple machines.
        Students will understand mechanical advantage.
        Students will learn the engineering design process.

Objectives:

        Students will be able to design and build simple machines and engineering mechanisms as part
         of a simple tower crane.
        Students will be able to calculate the mechanical advantage of the design for their tower crane.
        Students will be able to follow the engineering design process in building a model of a tower
         crane.

Background Information:

        The crane is a lifting machine that              of the applied force[2]. Crane technology
employs several other simple machines to                 continued to advance through the Middle Ages
achieve mechanical advantage. Most modern                and into today where cranes are used in many
cranes are capable of lifting and lowering               areas of our daily lives.
several tons of equipment or materials as well
as moving them about horizontally. Today,
cranes are used in construction, transportation
and in manufacturing wherever heavy loads
have to be moved, but cranes came into use
over three thousand years ago.

        The earliest known example of a crane,
the shaduf, was found in ancient Egypt and is
believed to have been in use around 1500 B.C.
[1]. The shaduf was really a simple first class
lever used to raise water in buckets from rivers,                  Figure 1: Tower Crane Components
but it was capable of both vertical and
                                                                 Tower cranes are a particular type of
horizontal transport of a load. Around 515 B.C.
                                                         stationary crane that are used mainly in
the Greeks came up with an incremental
                                                         construction where they are relatively
improvement on the shaduf that employed a
                                                         inexpensive and easy to construct in tight
pulley to increase the mechanical advantage
                                                         spaces. In fact, some tower cranes are actually
[2]. The next advance in crane technology was
                                                         used to build themselves. Usually, tower cranes
introduced by the Romans in their treadwheel
                                                         are made up of the following parts: the base, a
crane, which again increased mechanical
                                                         slewing ring (turntable) for rotation, the tower,
advantage, this time by increasing the lever arm
                                                         the boom and a lifting hook. The arrangement

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2/1/2010                                                                   Baltimore Polytechnic Institute   Engineer


of these parts can be seen in Figure 1. In this           calculate the mechanical advantage that it
project you will design and build a working               provides in lifting loads.
mechanical replica of a simple tower crane and

Concepts:
    Students will understand Mechanical Advantages of pulleys and levers.
    Students will be able to identify and construct Simple Machines such as levers and pulleys.

Materials:
    Corrugated cardboard                         20 in x 30 in
    Scissors                                     1 ea.
    Glue stick                                   1 ea.
    Tape (clear, single-sided)                   1 roll
    Flexible drinking straws                     5 ea.
    Utility (Pen) Knife                          1 ea.
    Twine                                        3 ft
    Hole Punch (Single)                          1 ea.

    *   Additionally, students may need a pencil and a compass for drawing circles.

Procedure:

    1. Each group of students should choose specific actuators for each moving part (e.g. boom, lifting
       hook, and turntable) and assign one of their team responsibility for its design. Use the answers
       from your homework assignment to help you choose your actuators.
    2. Come up with designs on paper for each of the moving parts; your design should include the
       entire power train for each part. A separate drawing should show how all three designs fit
       together to create the operation of the tower crane. Your designs have to be approved by your
       instructor to proceed to the next step.
    3. Use your paper design to help you construct a working model of the tower crane using
       inexpensive materials (corrugated cardboard, drinking straws, twine, tape and glue).

Sources:

    1. http://www.waterhistory.org/histories/nile/
    2. http://tripatlas.com/Crane_(machine)#Ancient Greek cranes
    3. http://en.wikipedia.org/wiki/Crane_(machine)




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