Motorized Pneumatic Pump

One of my plans for 2012 is to build a pneumatic walker. Therefore, I have to guarantee a sufficient airflow. Main restrictions are space and of course weight. So, my first decision was to use only the Power Functions M-Motor (58120c01) instead of the far more powerful, but two times heavier XL-Motor (58121c01).

After several attempts with different arrangements and a destroyed Pneumatic Pump (5107-1) (yes, I removed the spring and afterwards it couldn't hold the pressure anymore), I started to copy some designs from other builders like e.g., Sariel's compressor and rocking compressor. But I was pleased with none of them.

I wanted something more stable and reliable and when I discovered radbot's concept, I was enthusiastic to build a frame housing those 8 Small Pumps (x191c01). To build it, I used 5 "Liftarm 5 x 7 Open Center Thick" (64179). Because of their numerous Technic holes, you can easily implement the pump in any other creation. The small dimensions of 7x10x10 studs improve the implementation as well.

Because of the 5.5L of the Small Pumps, I used the Pin Connector Perpendicular Long (32557) in order to achieve a 2L displacement on the crankshaft.

Pin Connector Perpendicular Long (32557) in order to achieve a 2L displacement on the crankshaft

 The two crankshafts are counter-rotating

To show you the pump in action, I made some videos. Especially the fancy crankshaft movement made me happy.

More detailed pictures to be found on Brickshelf.

With best regards,
Jan