Step 1: The Frame
The author used a 12 foot piece of 1/2 OD aluminum tubing. A solid bar or steel could be used as well. Bending the material was challenging. Most of the tubing bent was accomplished while cold, but a couple of places the author had to anneal, the aluminum for a safe bend.
It is recommended to mark the bend area with a few hash marks of household hand soap (bar) to gauge the temperate. The soap marks turns black when it is at a good temperature. The author did not use any specific measuring equipment for bending; it was visualized. The baby seat has an approximately 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 inches. The first bend, at the baby's head, is 14 1/2 inches wide.
Please reference the picture. What is not shown in the third picture is the spread that needed to be added at the bottom, to go from 14 inches to 19 inches. You want the upper portion to stay parallel, so the spread should happen at the bottom.
The author also added a bend at the tip of the head area that allowed the fabric to form a nice headrest transition, when tight on the frame. (Reference photo 4 for details.)
The author did not include a picture of the installed brace that was added across the frame. The purpose of the bar is to keep it from pulling in toward the center 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. The author needed the frame to remain taut against the fabric sling. However, the author didn't want to drill a hole in the aluminum tubing and weaken the structure. To accommodate, the author drilled the brace, cross piece, to fit the curve of the aluminum tube, photos 5 and 6.
The author drilled a hole to have tabs on each side of the pipe. The tabs are wrapped around the tubing, as in drawings 7 and 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 two of each piece. Please reference the picture for assembly. The author recommends at least triple stitching all of the seams, and to reinforce higher stress points on the seat area with a strong binding tape.
Step 3: Attachment
For the attachment system, the author used 2 pieces of 7/8 inches OD 5/8 inches ID X 16" aluminum tubing. These pieces were drilled and tapped, with 1/4 inches hole, 2 inches from the end. The author used a 1 inches threaded 1/4 inches 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 two 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, the author has temporarily attached the seat with zap straps, which worked quite well. The metal clamps were used for added security.
Step 4: Ta Da!
The product is ready for use.