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Lifts which are suitable for wheelchair users are often provided in both public and private buildings to improve accessibility - Leaving Cert Engineering - Question Question 1 - 2016
Question Question 1
Lifts which are suitable for wheelchair users are often provided in both public and private buildings to improve accessibility. The scissor lift mechanism shown can ... show full transcript
Worked Solution & Example Answer:Lifts which are suitable for wheelchair users are often provided in both public and private buildings to improve accessibility - Leaving Cert Engineering - Question Question 1 - 2016
Step 1
Describe, with the aid of a diagram(s), the operation of this type of lift mechanism.
Answer
The scissor lift operates using hydraulic cylinders that extend to raise the platform. When the hydraulic pump is activated, it drives the cylinders, causing the scissor arms to unfold and lift the platform upwards.
A diagram illustrating this mechanism would show:
- Hydraulic cylinders: These are connected to the platform and responsible for lifting.
- Scissor arms: They connect at pivot points and allow the platform to rise to various heights while maintaining stability.
Step 2
Outline one other mechanism that could be used to operate a wheelchair lift.
Answer
An alternative mechanism could be an electric screw drive. This operates by using an electric motor to turn a screw, which then moves a corresponding nut along the screw, effectively raising or lowering the platform. The advantage of using this mechanism is that it provides precise control over the lift's height while eliminating the need for hydraulic fluid.
Step 3
Describe clearly, with the aid of a diagram(s), a suitable steering mechanism for the kart shown.
Answer
A suitable steering mechanism for the kart can be a rack and pinion system. In this system, the steering wheel is connected to a pinion gear, which engages a linear gear called the rack. When the steering wheel is turned, the pinion rotates, sliding the rack left or right to direct the front wheels accordingly.
The diagram should depict:
- Steering Wheel: Connected to the steering column.
- Pinion Gear: Engaged with the rack.
- Rack: Linear component that moves as the wheel turns.
Step 4
Describe, with the aid of a diagram(s), a rear wheel drive propulsion unit for the kart.
Answer
A rear wheel drive system can utilize a chain and sprocket mechanism. In this setup, a sprocket is mounted on the motor shaft, which drives a chain connected to sprockets on the rear wheels.
This system provides the necessary torque to propel the kart forward. The diagram should illustrate:
- Motor: Generating power.
- Sprockets and Chain: Transmitting power to the rear wheels.
- Rear Wheels: The point of contact with the ground, essential for movement.