Introduction: BiCrawler Assistive Technology

About: I started out my agricultural engineering career serving farmers with disabilities for Breaking New Ground at Purdue University. I then moved to Lowell, Michigan to be a dairy farmer and started a vegetable ma…

The BiCrawler helps people who cannot crawl or use their legs to work along the ground in fields, gardens and flower beds. People in developing countries can sit on the platform to access latrines. It is made by welding bicycle wheels to a rebar frame with wood platform.


Old bike with 26-inch (66 cm) wheels

17-feet of 1/2-inch (13 mm) rebar

Abrasive cut-off wheel and welder

Step 1: Find Dilapidated Bike With Good Wheels

A bike with wide tires at least 26 inches (66 cm) diameter works well for adults. Children or smaller people can use bikes with smaller wheels. Larger wheels with wider tires will roll over soft soil and obstacles more easily. Be careful on hills, because this BiCrawler will ROLLLLLL!

Step 2: Cut Wheel Arms Off the Bike

Cut the wheel arms off the bike. Cut them even with the inner side of the wheel rim. Be careful to not cut any spokes.

Step 3: Cut Rebar and Weld Into a Rectangle With Short Bars on Top

Cut 4 pieces of rebar 28-inches (71 cm)

Cut 2 pieces of rebar 32-inches (81 cm)

Cut 1 piece of rebar 22-inches (56 cm)

Make a rectangle with 2 28-inch pieces and 2 32-inch pieces.

Lay the ends of the 28-inch pieces on top of the 32-inch pieces.

Make sure the corners are square.

Weld the rebar corners all the way around both pieces.

Step 4: Elevate Rectangle Frame 4inches and Stand Up Wheel Inside It

Turn over the welded rectangle frame from step 3 and set it onto blocks so the 32-inch sides are elevated 4-inches.

Stand up the wheel inside the frame so the wheel arm hangs straight down and touches the side of the 28-inch bar.

Center wheel on the 28-inch bar.

Use a square or plumb line to make sure the wheel is vertical.

Use equal width spacers to make sure the wheel is parallel with the rebar.

Once the wheel is carefully positioned, weld the wheel arm onto the rebar frame.

Step 5: Position Second Wheel and Weld on Opposite Side

Repeat step 4 with the second wheel.

Step 6: Weld Inner Rebar Parallel to Wheel

After both wheels are fastened to the outer frame rebars, weld the inner 28-inch (71 cm) rebar to the frame.

Position the inner 28-inch rebar so it touches the side of the wheel arm.

Make sure the inner rebar is parallel to the outer rebar.

Weld the ends of the inner rebar to the frame. DO NOT WELD THE WHEEL ARM TO THE INNER BAR YET!

Step 7: Make Sure Wheel Is Vertical

Use a square or plumb line to make sure the wheel is vertical.

Double check that the wheel is parallel with the 28-inch rebars.

NOW weld the wheel arms to the inner rebar.

Step 8: Weld Support Rebar Across the Inner Rebars

Weld the 22-inch (56 cm) rebar across the center of the 2 inner rebars that were welded to the wheel arms in step 7.

Step 9: Attach a Platform Between the Wheels With Cords

Make a platform to fit between the wheels from wood, sheet metal, or whatever rigid material is available. Add padding as desired.

Drill holes in the platform and tie cords through the platform around the rebar frame.

Step 10: Shape Platform for Individual User Task and Preference

The BiCrawler will roll downhill very fast! Be careful on smooth slopes to park the BiCrawler sideways so it does not roll away. Adding a 2-inch (5 cm) block at the front of the platform will allow the user to tilt forward and stop the BiCrawler from rolling.

People sit or lay on the BiCrawler platform with their weight balanced on the wheels. By leaning forward and back, they can stay balanced on the wheels or rest one end of the platform or the other on the ground. When balanced there is very little friction between the BiCrawler and the ground, so it rolls easily.

The BiCrawler may be used by a person who is paralyzed and needs to do tasks close to the ground such as vegetable planting/weeding/harvesting, child care, or using a latrine. In such instances a larger platform that can accommodate a lying down position or sitting position might be desired.

People with knee and hip impairments that cannot crawl may prefer a seat on a smaller platform.

The BiCrawler can be propelled by pushing on the wheels by hand like on a wheelchair. It can also be moved by pushing/pulling with the feet or hands on the ground. Some people tie a rope along the length of their field and pull on the rope to move the BiCrawler.

It is generally easier to push the BiCrawler backward than pull it forward.

It is very mobile and can spin on a dime.

The wheels are spaced 26-inches (66 cm) apart, so vegetable rows planted 36-inches (90 cm) apart will be easy to roll between.