Specifications

The tower crane consists of 5 parts - Base Plot, Tower (Mast), Horizontal Arm (Jib), Elevating Mechanism and Trolley

Base Plot

A wooden base with a pit of area of cross section 80 mm x 80 mm and depth of 60 mm will be provided by the organisers. The tower portion of the crane must fit into this pit for proper anchorage.

Figure 1

Tower

1. The height of the tower must be a minimum of 500 mm above the wooden base and below the horizontal arm.
2. The cross section of the tower must be 80 mm x 80 mm at all times upto a height of 300 mm above the wooden base.
3. The tower height above the arm is not constrained.

Horizontal Arm

1. The length of the arm must be a minimum of 600 mm total.
2. The length of counter-weight section of the must not exceed 300 mm from the centre of the tower.
3. The cross section of the arm may not exceed 160 mm x 160 mm.
4. The arm can be supported by a maximum of 4 threads.
5. Participants are advised to make a flat structure in the counter-arm section for smooth loading and unloading of the counter-weights.

Elevating Mechanism

1. The lifting mechanism must be motorized.
2. Participants are allowed to use standard motors, gears, pulleys (cotton thread reels) and ready made gear assemblies for this mechanism.
3. The rope with hook to be attached to the block for lifting will be a cotton thread of diameter 2 mm.This wil be provided by the organizers.The participants have to use only this.
4. The power supply for the elevating mechanism may be placed off the crane, on the platform provided.
5. The maximum potential difference between any two points must not exceed 24 V.
6. The participant must ensure that any electric wiring of the mechanism does not interfere with lifting.

Trolley Mechanism

1. The trolley will be used to shift the lifted weight along the length of the arm. This is done by placing the elevating mechanism on the trolley.
2. The trolley mechanism may or may not be motorized.
3. Direct human contact with the trolley is not allowed. Manual pulling of strings is allowed.
4. The trolley can be connected with the counter-weight platform to allow for shift of counter-weights as the trolley shifts.
5. Individual counter-weight shifting mechanisms can also be made.

Figure 2

Materials to be used

1. Standard pop sickle sticks/ice-cream sticks of maximum 12 cm in length, maximum 1.5 cm in width and maximum 4 mm thick.
2. Only Adhesives (Synthetic white adhesive or single component cyano-acrylate adhesive) can be used to build the structure. (Adhesives such as M-Seal® are not allowed)
3. Cotton threads of diameter 1 mm. To verify this constraint each team must bring a 1 m long sample of the string used by them. (To verify the diameter of the string, it will be wound about a cylindrical object (like a pen). 10 turns will be wound about a cylindrical object. The length of the string will be measured along the axis of the cylinder. Thus the diameter of the string would be equal to the length of the string along the axis of the cylindrical object divided by number of turns wound about it).
4. Motor ready made gear assemblies, gears, pulleys, threads (cotton,1 mm diameter) and rubber bands (1 mm diameter) can be used only for making the elevating mechanism and trolley.

View the Rules

Building Rules

1. The pop-sickle sticks can be trimmed and used in smaller pieces.
2. Pop-sickle sticks can be stacked to make stronger elements.
3. The structure of the crane must be made entirely of these sticks and adhesives.
4. Elevating mechanism and trolley can be made from other materials specified.
5. Threads cannot be used to reinforce any joints in the structure.
6. The structure may not be painted, sprayed or dipped in any coating material. All glue should be removed from surfaces that are not bonded together.
7. Each team will be provided 1 m of standard cotton thread on the spot to secure any joints which they feel are critical before the crane is tested.
8. All motors and pulleys must be placed on the structure. Only the power source can be placed on the ground.
9. Participants are advised to keep a minimum of 10 cm width to place the counter-weights. Details of the weights would be provided on the spot.

Testing

Round 1

1. The weight of the structure consisting of pop-sickle sticks and threads will be considered (excluding the weight of the motor/elevating mechanism). The participant will be given time to integrate the elevating motor with the structure on-site.
2. Participants will be asked to place desired counter-weights on the counter-arm.Thereafter, the crane will be required to lift a load of 4 kg with the help of elevating mechanism upto a height of 10 cm. After the elevating mechanism is actuated, participant is not allowed to alter the position of the counter weight.
3. Structures will be tested for weight as well as the vertical deflection of the jib at a distance of 20 cm from the centre of the tower while the crane is under the load. This deflection will be taken with the help of a dial-gauge. Once the block is lifted to a height of 10 cm then the stable dial-gauge reading will be considered for the purpose of judging.

Figure 1	Figure 2

Round 2

1. A wall of height of 30 cm will be introduced in this stage.
2. The crane is supposed to lift a block of weight 4 kg to a height of 30 cm or more. Thereafter with help of the trolley mechanism the block should be taken across the wall and safely placed on the other side.
3. The trolley mechanism may be driven manually or with the help of an external motor.
4. Testing of the structure will involve the measurement of the maximum horizontal deflection of the tower while the trolley mechanism is functioning. The deflection will be measured at a height of 250 mm above the wooden base.

Definition of failure

A structure is said to have undergone failure if :

1. Structure fails to satisfy the above specified dimensional constraints.
2. Structure is broken at a joint i.e. it cannot take any load at that joint.

Figure 3	Figure 4
Figure 5	Figure 6

Any structure undergoing failure will be outrightly eliminated from the competition.

Judging

Scoring and Penalties for Round 1

A team can earn a maximum of 50 points in this round.
Scoring based on weight of the structure.
The participants will be awarded points on basis of the following formula:
Score = (Weight of lightest structure in the competition/Weight of your structure)*20

Scoring based on deflection of the horizontal arm
The participants will be awarded points on basis of the following formula:
Score = (Least deflection of any structure in the competition/Deflection of your structure)*30

Scoring and penalties for Round 2

A team can earn a maximum of 50 points in this round.

1. A team will earn 20 points if it successfully completes the aforementioned task.
2. A penalty of 5 points will be imposed if the block hits the wall while the task is being carried out.

Scoring based on horizontal deflection of the tower
The participants will be awarded points on basis of the following formula:
Score = (Least deflection of any structure in the competition/Deflection of your structure)*30

General Rules

1. Shape: Structure could be of absolutely any shape satisfying the above constraints.
2. Once the structure is weighed, you are not allowed to modify your structure in any way.
3. If the structure fails to satisfy any of the above constraints then it will be summarily rejected.
4. Any team that is not ready at the time specified will be disqualified immediately.
5. Judges' decision shall be final and binding on all.
6. The organizers reserve all rights to change any or all of the above rules as they deem fit. Change in rules, if any will be highlighted on the website/forum.

Team Specifications

A team may consist of a maximum of 3 members. Students from different educational institutes can form a team.

Eligibility

All students with a valid identity card of their respective educational institutes are eligible to participate.

Certificate Policy

1. Certificate of excellence will be awarded to the top 3 teams.
2. Certificate of participation will be awarded to all the teams whose cumulative score for two rounds is 40 points or more.

View the Resources

Resources

Assembly of a Tower Crane demonstration
How Tower Cranes work
How Tower Cranes are built
Tower Crane at howstuffworks

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