Know your chair – Know where it comes from – Know the tools to be used
We know that for many clinicians, making adjustments to manual wheelchairs is intimidating. It can be hard to know which size of tool to use, and what bolt or screw does what. Plus there's always the worry that you'll break something on your client's wheelchair and inconvenience them.
To help, we've put together a brief guide on manual wheelchair maintenance for clinicians. It will go through metric versus imperial tool sizes, the common types of adjustments you'll want to make, and what tools are most important to have in your toolbag.
Know your chair – Know where it comes from – Know the tools to be used
Knowing where your wheelchair was manufactured, will give you an indication to which are the right tools to use.
Wheelchairs manufactured in the USA will generally use Imperial size bolts and screws (i.e. inches and feet) etc. whereas wheelchairs manufactured in Australia, Europe or Asia will use Metric sizes (i.e. millimetres, centimetres and metres). However this is changing, with Permobil (TiLite) and Ki Mobility using metric sizes despite being manufactured in the USA. If in doubt, you can check with us or download the user manual from the manufacturer's website.
Right tool = less hassles
The right or correct fitting tool makes it easier to undo bolts and screws and causes fewer problems in the long run.
Use physics – Leverage, leverage, leverage
Often on new wheelchairs bolts can be machine tightened or done up extremely tight. This makes it difficult to undo these using T-handled allen keys, screw drivers and other tools with short levers. To overcome this use L-shaped allen keys with an extension on the lever arm to get maximum leverage and decreased resistance.
What makes up the ideal tool kit for therapists?
The following suggestions of tools cover a broad variety of wheelchairs and allow most of the common adjustments and repairs to be done:
- Spanners – 3/8″, 7/16″, ½”/ 10mm, 11mm, 13mm
- A socket set can make life easier but is occasionally harder to gain access to the bolts.
- Sometimes two of the same size spanners are required – one to hold the bolt head and one to hold the nut.
- Adjustable Wrench – this can be used for the odd sizes that the above spanners don’t fit.
- Allen Keys – 1/8″, 5/32″, 3/16″ / 3mm, 4mm, 5mm
- T-handled allen keys are great for quick adjustments but have very little leverage for tight, stubborn bolts. They also limit access to awkward screws and bolts, whereas L-shaped allen keys give you good leverage for tight bolts and you can use either end of the allen key. They are generally purchased in a set so you have just about all the options covered.
- Screwdriver
- Phillips Head
- Flat Head
- Stanley Knife
- Sticky back Velcro (it will always come in handy)
Common adjustments to wheelchairs and their clinical implications
Below are the common adjustments we might make to a manual wheelchair, and how they can affect other aspects of the wheelchair or the user's function. It's important to consider these implications when making any adjustments to a manual wheelchair. If in doubt, especially with things like castor angle, it's better to err on the side of caution and contact one of our Assistive Technology Consultants or Service Technicians for advice.
Adjusting the rake/dump/seat to floor heights on a manual wheelchair:
Front Seat to floor height:
- Changes overall height for transfers
- Redistributes pressure on the thighs and ischial tuberosities
- Changes the rake or seat angle, which impacts on hip angle
- Changes back angle
- Changes castor angle
Rear seat to floor height:
- Changes overall height of user which impacts on function and environment
- Redistributes pressure on the thighs and ischial tuberosities
- Changes shoulder position in relation to rear wheels
- Affects centre of gravity and stability
- Changes seat height for sliding side to side transfers
- Changes astor angle
- Can change sitting posture
Change the castor angle:
- The wrong castor angle creates poor performance of the wheelchair, causing extra strain on shoulders and difficulty propelling
- Decreases manoeuvrability
- The incorrect castor angle can be dangerous at high speeds
Adjust the centre of gravity on a wheelchair:
- Increases manoeuvrability
- Decreases strain on shoulders
- Increases ‘tippiness’, though whether this is desired is dependent on the user's sitting balance
- Decreases overall footprint/wheelbase of wheelchair (this can make it harder to get up curbs/gutters)
Adjust the camber angles:
- Increasing the camber can increase manoeuvrability
- Increasing the camber will increase wheelchair width, possibly affecting environmental access and doorway access.
- You also need to consider rear wheel spacing
Where did I go wrong and what do I do now – Common problems
Using incorrect size of allen key, spanners, wrenches and even screwdrivers
This can result in the stripping of bolt heads, allen key bolts and screws especially on tight critical bolts. If the bolt is completely stripped and is impossible to remove it's time to call in the service team because the bolt will need to be cut off or drilled out.
Not using advantages at our disposal
Consider the tools that you are using and if they are offering you the greatest physical advantage. Use long levers and the right fitting tool – Work smarter not harder.
Adjusting clamp style attachments
Predominantly seen in brake assemblies, a common mistake is to undo one of the two bolts a majority of the way – this creates an additional force on the second bolt and makes it extremely hard to remove (even if you use the right size tool and an appropriate size lever). In this case tighten the first bolt and undo the two bolts at the same time (about ½ a turn each bolt) until both have loosened.
Bolts into threaded vs smooth holes
If screwing into threaded holes ensure bolt is tightened prior to attaching nut and tightening that.
Our Assistive Technology Consultants and Service Technicians are also always available to answer any questions you have around maintenance, adjustments and tools- contact us today if you need any assistance.
