The document outlines the design of a gearbox project to lift at least 8kg to a height of 0.5m using a DC electric motor. It discusses using spur gears for their simpler design and efficiency. An initial model was tested using meccano gears with a 125:1 reduction ratio that lifted 4kg before the string broke. The document provides preliminary calculations for ascent time and power output. It aims for a 1:4400 ratio for the motor to lift 8kg with maximum efficiency.

1. Gearbox project
The creative journey

2. Design Criteria & Constraints
Material
1 A4 sheet of acrylic 3mm thickness
Glue
string/cord
Minimum performance
Lift at least 8kg
Lift up to at least 0.5m
Powered by a DC electric motor

3. Ideas
Planetary gear systems
Grinder gears
Extreme reduction gear sets
Cycloidal gear system
Extreme gear reduction
11 million to one
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content/uploads/2015/07/Untitled20.png

4. Why use spur gear in this project?
Simpler design, allows for more effort to be put into refinement.
Compact and simple to construct
Spur gear have a high power transmission efficiency
Less chance and easier to spot for fault

5. Model
We used meccano gears with a similar sized motor to see how it performs
Reduction was about 125 to 1
Lifts 4 kg, then the string broke
Flawed design

6. Gearbox initial design concept
Utilize spur gear
Housing for the gear hold together by box
joint
Two shaft for gear
Hole for mounting

7. Relevance and effectiveness
Implements conventional knowledge, allowing for more effective use of work
time.
From previous knowledge it does the job.
Fits within given parameters for project.
Works.
Safe; will work in conjunction with housing for safety.
Materials and design will provide enough operating hours for the task
required.

8. Problemisation
Less materials used, simpler design (less room for mistake or error).
The solution shows how existing solutions could be improved.
Predictable behaviour..

9. Preliminary calculations
Time for ascent: sqrt[(2hm)/dF]=t, from s=ut+1/2at^2
Where h=height for weight to ascend, m=mass of weight, dF=[T(out/r(finalShaft)]-mg.
Power Output: P=VI=ωΤ
Where P (watts)=output power, V (v)=input voltage, I=input amperage, ω=motor shaft speed, Τ=motor shaft torque
ω1/ω2=d1/d2
Where ω=angular velocity, d=pitch diameter
Ta/Tb=Na/Nb
Where T=torque, N=number of teeth
Aiming for ~1:4400 ratio for motor to lift 8kg with maximum efficiency (+10% output torque)

10. Fin.
Oliver Morton
Stefan Radulovic
Son Trinh