Crane Competition Pre-Engineering
Objective:
To design and build a lightweight crane that creatively lifts a variable load (P) from a structure a minimum vertical height (V) of 18 inches with a minimum horizontal (H) clearance distance of 9 inches from the edge of the tower or footprint of the crane. The crane structure may encroach on a 45° angle from the lifting point as shown in the diagram. The crane must lift the load a minimum of 6 inches to qualify. The crane that lifts the greatest load and meets the portfolio requirements showing proper application of the concepts introduced will be deemed the best design.
Materials.
Balsa Wood: the maximum size and length shall be 1/8" x 1/8" x 12'-0".
No other wood is allowed. No alteration, coating, lamination,
splitting or modification of any kind is permitted to the wood.
Wood glue
String (Twine) as supplied. String shall be used for the lifting cable and for substitution as tension members of the crane. The amount of length that may be used is unlimited.
Thin sheet metal (less than 1/16" thick x 1/4" wide max. x length as required) may be used for block and tackle assembly and/or for pulley axle support to prevent shear on balsa wood only.
Hardware:
One Electric Motor
One Motor Pulley Modifications may be made to this pulley to accept more string.
One Motor Mount must be attached to the crane.
Six Pulleys + Three Turning Blocks
Nuts and bolts or pins/nails as required for pulley assembly axle only.
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.
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