ROTARY
AIR PUMP
This project was my final submission for the Fall 2021 semester of my Industrial Design class. We were split into teams, with each team given a specific category of product to redesign. My team chose pneumatics. We researched various pneumatic technologies as a team and then individually picked a pneumatic tool to redesign – I chose an air mattress pump.
THE
PROBLEM
The problem(s) I have chosen to address is one of not only convenience and speed, but also of ergonomics. I have noticed all issues amongst friends and family, and a common occurrence I have seen is how everyone blames themselves after using the product. The strain put on the body due to the size and motion of the pump can cause strain on the lower back, with 100% of the required force coming from biceps and the front of the shoulder. Since pumping an air mattress can take a fair amount of time, almost every single use is followed negative muscle soreness and fatigue - and user always comments how “out of shape” they are after use. The size of the pump mixed with the posture required to use it does not depend on physical fitness to use; it is just not great for the lower back.
THE
SOLUTION
The Rotary Air Pump aims to ameliorate these issues by using a piston mechanism that can be cranked instead of pumped. Using an internal flywheel, the user simply needs to crank the flywheel to engage the piston into pumping air, and the freewheel will continue to spin after the user stops, allowing for the maximum amount of energy transfer to air output. To stop the rotary pump, the user simply needs to rotate the crank in the opposite direction. This motion is simple, it spreads the force over the joints and muscles of the entire arm and back, and the user can pump air much quicker than a typical air pump. Due to the consistent air output the rotary pump can also double as a fire bellow, which is incredible useful both at home and in a camping environment. Because the internals are all rotating around ball bearings, the maintenence of the system is as close to zero as it can get.
EXPLORATION
DEFINITIVE
DESIGN
I knew the form and external casing would be determined by the internal components, so once I had the flywheel mechanism roughly figured out I basically just form fit a casing on top - with a few tweaks for a more retro look. I decided on a three foot base for stability, with a foot in the front to prevent the pump from falling over when cranking - the front foot would stabilize for all the forward momentum, and the other two feet would be for the user to stand on.
To brake the internal flywheel I decided on using a coaster bike mechanism, found commonly on children’s bicycles, which is just a bike ratchet with an opposite threaded piece in the centre that extends into the rotating ratchet when the wheel is cranked in the opposite direction - thus braking the wheel and stopping motion. This prevents the flywheel from spinning continuously until it has lost all momentum, which can take quite a long time.
Some feedback recieved after presenting this concept, that I had not thought of, was - what does the users other hand do? There was no place to balance or rest your other hand while cranking the air pump, a problem which absolutely would have arisen had I made a rough mock-up to user test.
Also pointed out was the form of the handle, it was wood and a bit of an odd shape and potentially on the small side.
FINAL
DESIGN
All the feedback given in both the user testing and definitive design presentation led me to this final design - with a handle on the top casing, clips for the air tube to securely fasten to the edge of the pump, and a clip for the handle to allow easy storage. As it stands, the handle is connected to the main casing by 5 snap joints, though this could potentially need reinforcing depending on how much weight they can support. Further testing is required, and potential bosses may need to be added to help distribute any weight.
For the handle I modeled it after a bike handle and the GoodGrips vegetable peeler. After inquiring to a few individuals about handle shape and grips, it was pointed out that anybody with compromised gripping ability might have difficulty if the handle was not large enough.
The top casing is held together by a lip and groove joint, and snap fits into the main gasket. The air cylinder is connected vie a twist-lock to both the gasket and the bottom feet.
The internal flywheel mechanism is held in place by a cylindrical extrusion inside the casing, and the handle connects directly into the freewheel mechanism through a hole in the side. The piston and connector arm are connected via ball bearings to allow for a smooth motion and a maintenance free connection. The hand rest is connected via 5 snap fits, with further testing to determine whether additional bosses are needed for more support. All parts of the main bodyare expected to be injection molded ABS for strength, the crank shaft will be aluminum tubing, and the handle will be injection molded silicone for grip.
