By rolling the blue circle with radius 1 inside the black circle with radius 2 the fixed red point on the blue circle traces out the the green diameter in the black circle. | If red point and the green diameter is offset by the same amount we obtain a red circle moving back and forth in the green canal. | ||
The construction above is lifted to horizontal planes z = constant. | The blue circle is rolled a distance proportional to the height z. Observe that the blue circles no longer are above each other. | By rotating the picture in each horizontal plane the blue circles can be positioned over each other such as to form a blue cylinder inside a black cylinder. | The motion generated by letting the blue cylinder roll inside the black cylinder is in each horzontal plane the same as before. |
A series of pump chambers are formed and they move upwards as rigid bodies under the motion generated by the letting the blue cylinder roll inside the black cylinder. |