I'm a volunteer with the Tetra Society of North America.
We are a group with a wide variety of Maker minded people, who love the challenge of coming up with creative solutions to unique problems, that can arise from the day to day challenges of living with a disability.
This project is for a baby seat that would allow Sam, to be up close and cuddly with her new baby.
There were a number of challenges, with this project. First and foremost was safety.
It needed to have fairly simple attachment system, and easily removable.
Have baby up close, face to face.
Still allow for mobility, of the wheelchair, and keep everything secure.
Step 1: The Frame
I started with a 12' piece of 1/2 OD aluminum tubing. Solid bar, or even steel would work, as well. This was what I had on hand, and worked out great.
The bending was the tricky part. Most of it I was able to bend cold, but a couple of places I had to anneal, the aluminum for a safe bend.
If you mark your bend area with a few hash marks of household hand soap (bar) you will know you have a good temp. when the soap mark turns black.
The bending, I did free form and eyeballing the shape. The baby seat is about 45 degree angle, to the bottom rail.
Lots of trial fit, to make sure it clears the legs and fits the width of the seat, about 19". The first bend, at the baby's head, is 14 1/2" wide.
What is not shown in the 3rd picture is the spread that needed to be added at the bottom, to go from 14" to 19". You want the upper portion to stay parallel, so the spread should happen at the bottom.
I also added a bend at the tip of the head area, that allowed the fabric to form a nice head rest transition, when tight on the frame. Zoom in on photo 4 for detail.
I didn't get a picture of the installed brace I added across the frame, to keep it from pulling in toward the centre, when the baby is seated. You can see the positioning of this in the pattern photo, in the next step. It runs at the level of the baby's feet. I needed it to keep the frame taut against the fabric sling, but I didn't want to drill a hole in the aluminum tubing, and weaken the structure, so I drilled the brace, cross piece, to fit the curve of the aluminum tube, photos 5 & 6.
I cut the drilled hole to have tabs on each side of the pipe. The tabs are wrapped around the tubing, as in drawings 7 & 8. Epoxy to create a smooth surface for the fabric to slide on.
Step 2: The Sling
The seat is a sleeve that slides onto the frame, and is removable and washable. It is the same on both sides, apart from the restraint, that is only on the front side, so be sure to cut 2 of each piece.
I hope the pictures will explain the construction, better than a thousand words, but I will be happy to clarify anything if necessary.
I made sure to, at least triple stitch all the seams, and reinforced higher stress points on the seat area with a strong binding tape.
Step 3: Attachment
For the attachment system, I used 2 pieces of 7/8" OD 5/8" ID X 16" aluminum tubing.
These pieces were drilled and tapped, with 1/4" hole, 2" from the end. I used a 1" threaded 1/4" bolt , with a plastic wing nut.
The wing nut is tightened onto the smaller tubing, after the seat, is inserted into the mount. Pretty simple, but quite effective, and secure.
The 2 receiver tubes, slide along side the wheelchair seat and are secured in place with pipe clamps, around the frame of the chair.
In the photo I have it temporarily attached with zap straps, which worked quite well.
The metal clamps will give me a bit more peace of mind.