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Crane Project

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In this competition students creatively design, build  and test a lightweight crane that lifts a variable load (P) from a structure with a minimum vertical height (V0 of 18 inches with a minimum horizontal (H) clearance distance of 9 inches from the edge of the tower of footprint of the crane.  The crane structure may encroach on a 45 degree angle from the lifting point.

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The crane must lift a load a minimum of 6” to qualify.  The crane that lifts the greatest load and meets the portfolio and interview requirements showing proper application of the concepts introduced will be deemed the best design.

 

Standard U.S. pennies are used for the weights and counterweights.  Both the weights and the counterweights must be suspended from the crane.  Students must design a container to hold the pennies for the weight and the counterweight.  There are no restrictions except that the container may not be structural and cannot rest on the ground.

Creative Crane Competition Proposal and Rules

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Hints and Suggestions

  • The materials supplied in the kits have limits in strength.  Exceeding these limits will cause system failure.
  • Limits in strength can be increased with proper structure design.
  • Motors in these kits have limits in torque.  Exceeding these limits can cause motor failure.
  • Employing a properly designed transmission can increase the torque of the motors.
  • Motors can be burned out if overloaded.
  • The stability of the structure is an important consideration in the crane design.  Cranes can fill over or crumble if not carefully designed.
  • The most important hint that can be given to a design team is to take the time to test, test and re-test your crane.
  • The items listed above serve to encourage thinking on the pat of the students involved.  They are hints on how to solve possible problems; they are not solutions.  The design teams must come up with their own solutions.
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Objective

To design and build a lightweight crane that creatively lifts a variable load (P) from the structure with a minimum vertical height (V) of 18 inches and a minimal horizontal (H) clearance distance of nine inches from the edge of the tower or the footprint of the crane.  The crane structure may encroach on a 45 degree angle from the lifting point as shown in the diagram.  The crane that lifts the greatest load and meets the portfolio and interview requirements showing proper application of the concepts will be deemed the best design.

Materials – each team may use

Kit #841285 has enough motors, mounts, pulleys, and string for six teams of three students.  Kit 261684 includes the items listed above plus enough balsa wood for the items.

 

        String (twine) as supplied.  String shall be used for the lifting cable and for substitution as tension members of the crane.  The amount that may be used is unlimited.

        Balsa Wood 1/8”*1/8” * 12’ and 1/8”*3/8” * 12.  No other wood is allowed.  No laminations or alterations to the wood is permitted.

        Glue type – no restrictions

        Miscellaneous items

        Thin sheet metal (less than 1/16” thick * ” wide maximum * length as required) may be used for block and tackle assembly and/or for the pulley axle support to prevent shear on balsa wood only.

        Nuts and bolts or pins/nails as required for pulley assembly axle only.

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Six pulleys (390592)
( single pulleys used to change direction of pull, not the amount of force), One motor pulley (#390397)

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One 12 V DC Electric Motor ( Kevin # 850887)

One motor mount that must be attached to the crane (#390572)

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Official Power Supply used the day of the Competition

  • Kelvin-K.P.S. Power Supply #101 Voltage Switch 12V DC, 1.5A (Kelvin 841052)

  1. Weights and Counter weights

        Standard U.S. pennies shall be used for the weights and counter weights.

        Both the weights and counterweights must be suspended from the crane.

        A container shall be designed to hold pennies for weights and counterweights, there are no restrictions except that the container may not be structural or rest on the ground

  1. Structural Testing Criteria (laboratory experiments and testing)

        Organize the Design Team and Assign Specialists

        Tension and Compression Members

        Column Buckling

        Horizontal Component Vector and Changing Angles

        Braced Length and Column Buckling

        Mechanical Advantage of Pulleys

        Crane Stability and Rotational Overturning

        Possible Structural Design Solutions (sketch and layout)

  1. Aesthetic Criteria

        Shapes of Cantilevers, Cranes and Towers

        Possible Aesthetic Design Solutions (sketch and layout)

  1. Preliminary Design, Testing and Assessment

        Draw Preliminary Design Solutions

        Build and Test the Best Prototype Design Solution

        Analysis and Recommendations to Improve Design

  1. Final Solution

 

      Portfolio Requirements:

      All teams shall complete the laboratory experiments and library assignment and compile them into a portfolio. All members of the team need to evaluate the performance of all team members and list their contributions to the group. Assign a # grade to each member.

Crane Related Research Websites
 
Howstuffworks "How Tower Cranes Work"
Tower cranes rise 150 feet in the air and lift up to 19 tons. Plus, they actually
build themselves! They're simply amazing. Learn how these structures ...
 
Howstuffworks "How Hydraulic Cranes Work"
Hydraulic cranes perform seemingly impossible tasks, lifting 70-ton objects with
absolute ease. See the simple design behind the Herculean results.