1.1 PROBLEM STATEMENT:
Design and build a tower crane using
pop-sickle sticks which can lift a stationary weight and carry it over a wall
to place the weight on the other side of it.
2.1 STRUCTURE SPECIFICATION:
The tower crane consists of 5 parts - Base Plot, Tower (Mast),
Horizontal Arm (Jib), Elevating Mechanism and Trolley.
2.1.1 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 organizers. The tower of the crane must
fit into this pit for proper anchorage.
2.2 Tower (Mast)
1. The tower height must be a minimum of 500 mm above the wooden base
and below the arm (jib).
2. The cross section of the tower
must be 80 mm x 80mm at all times upto a height of 300 mm above the wooden
base.
3. The tower height above the arm
is not constrained.
2.3 Arm (Jib)
1. The length of the arm must be a minimum of 600 mm.
2. The length of the counter-weight section of the arm 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-weight section for smooth loading and unloading of the counter-weights.
2.4 Elevating Mechanism
1. The lifting mechanism must be motorized.
2. Participants are allowed to
use standard motors, gears, pulleys (cotton thread reels) and readymade 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 will 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.
2.5 Trolley
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-arm platform to allow
for shift of counter-weights as the trolley shifts.
5. Individual counter-weight shifting mechanisms can also be made.
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.
Adhesives (Synthetic white adhesive or single component cyano-acrylate
adhesive) can only 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, readymade gear assemblies, gears, pulleys, threads (cotton, 1 mm
diameter) and rubber bands (1 mm diameter) can be used in the elevating
mechanism and trolley only.
BUILDING RULES:
1. The pop-sickle sticks can be trimmed and used in smaller
pieces.
2.
Pop-sickle can be stacked to make stronger elements.
3. The structure of the crane must be made entirely with
these sticks and adhesives.
4.
Elevating mechanism and trolley can be made from the 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.
3.1 TESTING AND JUDGING
3.1.1 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 mechanism with the structure on-site.
2. Participants have to place
desired counter-weights on the counter-arm. Thereafter the crane will be
required to lift a load of 4kg with the help of elevating mechanism upto a
height of 10cm. After the elevating mechanism is actuated, participants are 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 arm at a distance of 20 cm
from the centre of the tower while the crane is under the load. This deflection
will be measured 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.
3.1.2 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 is
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 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.
3.1.3 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. Any
structure undergoing failure will be out-rightly eliminated from the
competition.
3.2 Judging Criteria
3.2.1 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
3.2.2 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
4.1 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.
4.2 Team Specifications
A team may consist of a maximum of 3 members. Students from different
educational institutes can form a team.
