Our family in Thailand adopts one handicapped dog, ‘Messi’. He was contracted with some kind of virus since he was around 1-2 years old (when we adopted him) and caused his rear legs to be paralyzed. Though his front 2 legs are still functioning, but they do not have enough strength to support his whole weight. So we’ve got him a fully supported dog wheel-chair for his use.
The current dog wheel-chair, made by veterinarian hospital in Thailand, cost Bht 5000 (~USD 155). This is considered very expensive in Thai currency. I’ve done some search for the fully supported dog wheel-chair cost in the US, and it ranges from ~ $350 - $800+ (for medium size dog).
For this winter break, we are visiting our family in Thailand, so I’ve got
a plan (or a goal) to design a DIY low-cost dog wheel-chair for Messi, that could also benefits other handicapped dogs.
The design is intended for a medium size dog but can be easily modified for smaller or larger dogs. I choose PVC piping sytem as the main material for its low cost, light weight, sufficient strength and easy to work with for DIY. For this design, I use the Schedule 40, ½” PVC piping system, easy to find at every hardware store and is strong enough to support a medium size dog.
Step 1: Bill-Of_Material
Per the BOM, the main cost items are the wheels. These are Amazon pricing
for brand new items. However, you probably can find those items at a much lower cost from a junk yard, estates sales or flea market.
Step 2: Tools
- PVC Pipe cutter, available at many hardware store (@Home depot ~ $12)
- Hack saw can also be used, but PVC pipe cutter is a lot more quicker and easier to use.
- Electric drill. Note: for prototype build, I use Flat head phillips, Wood screw #6 to hold each PVC pipe joint togeter. You can use PVC primer/glue, once you’ve got all the dimension adjusted to fit your dog.
- Drill bit for #6 screws with countersink: 3/32” drill with 5/16” counterbore.
- Drill bit for ½” axel bolt: use ½” flat blade drill bit.
- Misc: Ruller, marking pencil/pen,knife...
Step 3: Detail Design DWG
A single 2D drawing is provided and is simple enough for self explanatory.
All dimensions are in inches. Dimensions shown in the drawing are good start for general medium size dog (Messi weights ~ 19 kg).
Height, Length and Width can be adjusted to custom fit your dog as shown.
Step 4: Construction 1: Cut PVC Pipe to Length
Cut ½” PVC to length as shown in the table above.
Length are in inches. Length can be rounded up to the nearest 100th of an inch (2 decimals). A tolerance of +/- 0.02" would be sufficient.
Step 5: Construction 2: Rear Axle Hole
Drill ½” hole into 2x TEE coupling as shown. The hole is for the ½” axle bolt for the rear wheel.
Step 6: Construction 3: Assemble, Fit Check
Assemble all the pieces together per the drawing. Can start with just hand press-fit, the friction is high enough to hold all the pieces together.
Step 7: Construction 4: PVC Joints
For this prototype, I use #6 wood screws to hold all the joint together as shown. Only one screw per joint. Use the #6 drill with countersink at approximately ½” from the edge of each joint piece.
Step 8: Construction 5: Front Caster Wheels
For the front Caster wheel, cut a short piece of PVC pipe approximately ¾” long. Use Duct tape to wrap around the stem of the caster till the diameter can be snugly fit inside the ½” PVC piece as shown. Then insert the caster with duct tape and PVC pipe into the front TEE piece as shown.
Step 9: Construction 6: Rear Wheels
Assemble the Rear wheel into the ½” hole of the TEE piece using the axle bolt, washer and locknut as shown.
Step 10: Construction 7: Body Support
Body support: Note: this instruction does not include the detail of the body support. The rear body support was transferred from the old wheel chair. As shown in the picture, one can be constructed using steel rod, plastic hook, foam tube, … items that can be acquired from general hardware store. For the front body, adjustable luggage strap was used. soft fabric can be added for more comfort. Adjustable straps also allow for easily height adjustment. Pictures shown as examples:
Step 11: Construction 8: Size Adjustment
Size adjustment: with 'Messi' strap into the wheel chair, I have to reduce the length by about 2.5” so that the front wheel casters will approximately line up with his front legs.
Rear leg support can be added with hanging strap attach to the rear cross bar similar to the original wheel chair.
Step 12: Conclusion
Messi front legs are still function but not strong enough to support his overweight body, so all 4 wheels are needed. The same design can be easily modified for using only the two rear wheels.
Messi does not walk that much anymore. So it is hard to evaluate how good the design is. We hope that he will do more exercise, as much as he can. I also hope that the PVC Dog Wheel chair design can be beneficial to many more handicap dogs around the world.