Manual pneumatic valve

thingiverse

This is a manual pneumatic valve, actually two valves, that allows air both in and out of a downstream chamber. I designed this to test a robotic arm actuated with pneumatic muscles. The valve is quick to print and simple to operate, allowing air in and out of the muscles. It uses 6mm PVC pneumatic tube and avoids applying pneumatic pressure to printed parts that tend to be porous. They have been tested up to 400 kPa or 60 psi. This is intended for temporary use, such as prototyping, since it relies on major deflection of the tube. To assemble this design, two pieces of 4mm shaft are required, each 16mm long, and may be substituted with a M4 bolt not tested yet. Two M4 screws with nuts and rubber from a bicycle tube or similar are also needed. This design includes two valves. In its default state, no air flows in or out of the controlled chamber when both valves are parallel to the valve body. When either valve is lifted, air flows into or out of the controlled chamber accordingly. The in valve operates by squashing the pneumatic tube to prevent flow into the system, while the out valve requires a small hole to be drilled in the tube to allow the air to escape. To assemble this manual pneumatic valve, print one of each of the four parts. Cut out a small piece of rubber that fits snugly into the valve body. Drill a small hole, 2-3mm in diameter, in the pneumatic tube and mark the opposite side to help with alignment. Push the tube into the valve body with the hole facing down onto the rubber, then place each valve in position. Push a 4mm shaft through the valve body and each valve to hold it in place. Test the valve now and note that the out valve may leak due to printing tolerances. To fix any leaks, place some paper under the rubber. Finally, use M4 screws to secure the tube holder in place and these can also be used to mount the valve to a backing board.