Lawn Mower Mechanics: Functions, Design, and Maintenance
Grass Cutting Mechanism
How is the grass cut?
The grass is cut by the blades.
How is the height of the cut adjusted?
The cut is adjusted by spacers (to adjust blade height).
What is the purpose of the fan?
The purpose of the fan is to suck in air.
How do the cuttings enter the grass box?
The cuttings enter the grass box via the impeller fan.
How is power provided?
Power is provided by a power lead.
How is the motor protected from grass intake?
The motor is protected from grass intake by a grass filter.
What is the function of the hood?
The function of the hood is protecting the electric motor.
Key Functions
The following list outlines key functions of the lawnmower:
- Provide motor
- Rotate blade
- Use spacers
- Rotate impeller
- Position blade height
- Provide horizontal velocity to blade
- Achieve air-flow
- Provide duct to grass box
- Provide grass box
- Impact grass with sharp edge
- Bring grass upright
- Use spacers
- Store cuttings
- Cut grass
- Collect cuttings
- Trim lawn
Product Lifecycle and Design Considerations
Why do products have a finite life?
Because lost sales are never made up as changes occur in the market.
How can too little quality ruin a producer?
If faulty goods have to be recalled.
What does a customer require of any product?
Functionality, quality, affordability, and availability.
What is a window of opportunity?
It is the life cycle profits.
What is FAST?
It is a Functional Analysis System Technique diagram.
What does it (FAST) allow the designer to do?
This enables the designer to understand the functional relationships of the system being designed.
How can a design team use FAST to put value into a design?
By combining a number of functions into single parts, thus reducing the number of parts and saving cost in both material and labor.
Airflow and Cutting Transport
How are the cuttings transported?
The cuttings are transported by achieved air-flow.
How is air-flow achieved?
The air-flow is achieved by rotating the impeller fan.
How is the blade height positioned?
The blade height is positioned by adjusting the spacer.
How is horizontal velocity provided to the blade?
The horizontal velocity is provided by rotating the blade.
How is the grass impacted with a sharp edge?
The grass is impacted with a sharp edge by positioning the blade.
Why is a grass box provided?
The grass box is provided to store the clippings.
Why is the grass brought upright?
It’s brought upright to be cut.
Why are spacers used?
They are used to position the blade.
Why is air-flow achieved?
It’s achieved to transport the cuttings.
Why is a motor provided?
It’s provided to power the fan and the blades.
Component Functions
Shock absorber – absorbs shocks – absorbing shocks
Signal generator – generates signal – generating signal
Speed governor – governs speed – governing speed
Battery charger – charges battery – charging battery
Pressure regulator – regulates pressure – regulating pressure
Circuit breaker – breaks circuit – breaking circuit
Hardness tester – tests hardness – testing hardness
Fuse holder – holds fuse
Engine immobilizer – immobilizes – immobilizing engine
Engine temperature sensor – senses temperature – sensing temperature
Component Actions
Reduce the speed – speed reducer
Indicate the level of oil – oil level indicator
Grind the surface – surface grinder
Inject fuel – fuel injector
Filter oil – oil filter
Cut wires – wire cutter
Sense moisture – moisture sensor
Compress air – air compressor
Convert digital to analogue – digital to analogue converter