Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bmsc wheelchairs > Unit 2: Wheelchairs > Flashcards

Unit 2: Wheelchairs Flashcards

1
Q

What are the prime functions of wheelchairs

A

To compensate for locomotor disability

To enable person to move from place to place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the methods of wheelchair propulsion

A

Occupant propelled
Attendant propelled
Powered wheelchairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 main styles of occupant propulsion

A

Bilateral arm
One arm
Bilateral legs
One arm one leg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Benefits of handrim propulsion

A

Simple, lightweight, easy to manoeuvre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Disadvantage of handrim propulsion

A

Depends on good hand grip and strong pushing force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How can handrim propulsion be made easier

A

Use larger cross-section handrim tubing
Use indentations/capstan fittings
Use non-slip finish plastic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Problems with handrim modifications

A

Indentations: friction burns

Non-slip finish: splintering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is handrim diameter usually matched to wheel diameter

A

Allows user to grip both at same time to aid propulsion

Minimises forces required to propel the chair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Benefits and disadvantages of smaller diameter handrims

A

Increases the max speed

Requires higher force for propulsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Benefits and disadvantages of larger diameter handrims

A

Less force required to turn wheels

Lower maximum speeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the optimum position of the handrim/wheels

A

As close to the body as possible

Allows arm movement to commence slightly posterior to the trunk and travel to just short of full elbow extension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What term is used to describe angling of the wheels to bring them closer to the occupant

A

Cambering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What mechanisms provide the most efficient use of bilateral arm propulsion

A

Level or crank mechanisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do you propel a wheelchair with one arm

A

Grip both handrims to move forwards and backwards

Push one handrim to change direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are disadvantages of one arm control

A

Limited speed, range and manoeuvrability

Requires good hand grip, arm strength and control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How should a leg-propelled wheelchair design differ

A

Seat should be lower to allow feet to contact the ground

Ensure max clearance behind the legs to avoid impeding movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How are attendant propulsion wheelchairs usually operated

A

Push handles at the rest of the backrest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What measure is used to give the capacity of a battery

A

The amp-hour rating

Note: normal ratings are 20-amp hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the limitations of powered wheelchairs

A

Battery operated: heavy, need recharging, finite life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 2 types of battery

A

Lead acid batteries

Gel batteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the benefits and disadvantages of lead acid batteries

A

Benefits: greatest capacity, last longer, cheaper
Disadvantages: heavy, bulky, require regular topping up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the benefits and disadvantages of gel batteries

A

Benefits: unspillable, smaller, lighter, more easily transported
Disadvantages: dont have as much capacity as lead batteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are motors used for

A

To drive the rear (or front) wheels via belts or gearboxes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe a beneficial function of motors

A

Can be disengaged from the wheels to allow the wheelchair to move when the battery is flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is steering controlled

A

By feeding differential power to the motors

Note: the wheelchair moves away from the side which is fed more power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How are sharp turns achieved

A

Turn one motor forwards and one in reverse

27
Q

What are the 2 main types of braking

A

Parking brake
Regenerative braking
Note: can also brake manually by slowing down the handrims

28
Q

What is regenerative braking

A

Slowing down the speed of the motors in order to slow down motion of the wheelchair

29
Q

When is parking braking used

A

When the wheelchair is at a standstill

30
Q

What is the function of the control system

A

Detects actions of the occupant and translates this into the appropriate operation of the motors

31
Q

What is the ‘bang-bang’ controller. Give a benefit and a disadvantage

A

A control system that operates the motors at full power only
Benefit: good if no fine control of hand position
Disadvantage: creates very fast accelerations that are difficult to control

32
Q

What are the 7 main performance characteristics of the wheelchair

A 
Range
Max speed
Acceleration
Stability
Obstacle climbing
Manoeuvrability
Environment protection
33
Q

What are the typical max speeds of an indoor and an outdoor wheelchair

A

Indoor: 2mph
Outdoor: 4-8mph

34
Q

What is used as a good indication of the manoeuvrability of a wheelchair

A

The minimum width of corridor in which a wheelchair can turn to face the opposite direction

35
Q

How is the stability of a wheelchair measured

A

The steepness of the angle to which a wheelchair can be tipped before it falls over

36
Q

What 2 factors govern the wheelchair stability

A

The size of its wheelbase and the position of the centre of gravity
If the centre of gravity is within the wheelbase then the object remains stable

37
Q

What gives a larger wheelbase: castors in trail or in leading position

A

In trail

38
Q

Where should the centre of gravity be to ensure max manoeuvrability

A

As near to the main wheels as possible

39
Q

What adaption may need to be made for a bilateral lower limb amputee

A

Set the main wheels back a few centimetres to maintain rearwards stability

40
Q

What are anti-tipping levers

A

Extension to tipping levers that contact the ground before the wheelchair becomes unstable in a rearwards direction

41
Q

What kind of tyres are most prone to instability/slipping when parked on a slope

A

Smooth hard tyres

42
Q

What do pneumatic-type brakes depend on

A

Sufficient inflation of the tyres

43
Q

What is an advantage of progressive action running brakes

A

Work independently of tyre inflation

44
Q

How to ratchet brakes work

A

Prevent rolling backwards when propelling uphill

45
Q

What factors influence manoeuvrability

A

The propulsion system

The castors

46
Q

What design characteristics of a castor affect its manoeuvrability

A

Resilience (hardness of the tyre)
Radius of swivel
Castor wheel diameter

47
Q

What happens to manoeuvrability as the occupant moves closer to the castors

A

Manoeuvrability decreases

48
Q

What is castor flutter/shimmy

A

Impairment of direction control due to castors vibrating widely on their swivels when moving at speed

49
Q

What 5 factors influence rolling resistance

A 
Wheel diameter
Tyre resilience
Bearing friction
Wheel alignment
Weight
50
Q

What happens to rolling resistance as wheel diameter increases

A

Rolling resistance decreases

51
Q

What happens to rolling resistance as tyre resilience decreases

A

Rolling resistance increases

52
Q

What is a benefit and a disadvantage of solid tyres

A

Benefit: less energy required for propulsion
Disadvantage: less comfortable when going over uneven ground, cannot climb obstacles

53
Q

What dimension of a wheelchair governs the height of the obstacle that can be climbed

A

The front wheel diameter

+/- assistance from anti-tipping levers and kerb climbers

54
Q

What are kerb climbers

A

A pivot structure that hits obstacles and swings down to lift up the front of a wheelchair

55
Q

What environment is the use of solid tyres restricted to

A

Indoor use on solid surfaces with no obstacles

56
Q

Benefits and disadvantages of foam-filled tyres

A

Benefit: cannot be punctured
Disadvantage: increased rolling resistance and weight

57
Q

What is the most common style of seating used

A

Sling-type

58
Q

How wide are most wheelchairs

A

Required seat width +5cm for wheels and frame

59
Q

What are the 3 main types of strength

A

Static
Impact
Fatigue

60
Q

Describe static strength

A

The ability to withstand a constant force e.g. weight of a person in the chair

61
Q

Describe impact strength

A

The ability to withstand transient loads e.g. blows to the chair when dropped/hitting a kerb

62
Q

What components of the wheelchair are vulnerable to impact strength loads

A

Castor forks, mountings and frameworks

63
Q

Describe fatigue strength

A

The ability to withstand variation in load over prolonged period of time (wear and tear)

bmsc wheelchairs (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions