Introduction: DIY Bumbo Wheelchair for Kids
These DIY pediatric wheelchairs are life changing for disabled children. It makes a great stable first wheelchair to let them explore the world. Maybe even get into a bit of trouble! :) With stainless hardware they can be used at water parks instead of expensive wheelchairs that may rust. This is a slightly larger version. it can be scaled down for a smaller infant bumbo seat with a smaller board. My son Cameron was born with SMA Type 1. You can follow his story of hope at https://www.facebook.com/groups/hope4cameron
Parts needed:
Seat: The one i used is called the mega. Bought it used on eBay fairly inexpensive. Other seats can be used but you may have to adjust the balance point and distance between brackets.
https://m.toysrus.com/product/index.jsp?productId=...
- Cutting board: http://amzn.to/2tdWARo
- Brackets: http://amzn.to/2tecZ8h
- Bearing spacers: http://amzn.to/2tNDz59
- Rear caster 3" http://amzn.to/2tecZ8h
- Front caster 2" http://amzn.to/2se3MrH
- Wheels: http://amzn.to/2se3MrH Currently out of stock. These look like they would work well. http://amzn.to/2se3MrH You can also find the strider ultralight wheels on ebay. Another good source is used strider bikes at yard sales that can be had for around $20.
- Optional bearing upgrade: http://amzn.to/2tNDz59 The bearings in the wheels are the same used by skateboarders. I upgraded to a set of higher quality sealed bearings.
Step 1: Base Assembly: Casters
Once completed the front caster will be off the ground. The front caster is only to prevent tipping too far forward.
The 3" caster mounts to the rear in the center about a 1/2 inch from the edge. The 2" caster mounts to the front the same way.
Pre drill the holes using a drill bit smaller than the screws. Wrap a piece of tape around the drill bit as a gauge to make sure you do not drill completely through the board. I recommend using stainless steel screws that are short enough to not go through the board.
Step 2: Wheel Brackets
On the wheelchair I built for my son i had the brackets fabricated out of stainless steel. Wanted to find a cheaper option for other parents to be able to do themselves. These Galvanized unistrut brackets are thick enough to not bend or flex and should be somewhat resistant to rust.
Drill holes down the edge of the long end of the bracket. Be sure to clamp the bracket in a vice when drilling for safety. These holes will be used for mounting the bracket to the cutting board with stainless screws.
The cutting board i used was 20" by 15" Start by measuring 9.5 inches from the front to mark the location for the wheels. The Mega Seat will compress and fit snugly with 14" between the brackets so i cut 1/2 inch from each side the width of the bracket. Alternatively you could just cut 1" off one side and run it through a router to round the edge. This step will vary depending on the seat you use and the child's weight.
Mount the brackets with only one or two screws for now. We will have to fine tune the alignment later.
Put some books under the cutting board so that it sits level with the rear wheel touching the ground. Hold the wheel up to the bracket and mark the location for the hole and drill it the diameter of the bolt being used to mount the wheel. This will ensure everything is level when the rear caster and wheels are on the ground.
Step 3: Wheel Alignment and Final Assembly.
At this point you can mount the wheels to the brackets. Instead of the shaft included with the wheel i would suggest using a stainless steel bolt, washers, and nuts to attach the wheel. Use the bearing spacers and bearing washers if needed to prevent binding. Once tightened the wheels should spin freely.
Now we need to align the wheels. Use a measuring stick to make sure the distance from the rim to the edge of the cutting board is even on both sides of the bracket. while keeping one screw in the bracket adjust the bracket so it is aligned correctly. Mark the bracket and drill/install stainless screws. Alignment will really help the chair move with less effort.
Once completed The threaded end of the bolt can be cut flush with a hacksaw. I did not use anything to mount the seat as it stayed in place very well when squeezed between the brackets. This also allowed me to adjust the seat for balance as needed.
Optional: The bearings in the wheels are the same used by skateboarders. I upgraded to a set of higher quality sealed bearings. http://amzn.to/2tNDz59