Abstract: The mechanism includes one member which may occupy one of two fixed positions and can be caused to change over from one position to the other at will. In order to accomplish rapid change over with minimum energy input and minimum impact, an elastic suspension of this member is provided and so arranged that the changeover process is substantially a half cycle of oscillation in which the moving member starts and ends with no or little speed of motion. The moving member is captured in the vicinity of, and held at the fixed positions, against the force exerted by the elastic suspension by mechanisms exerting short range forces upon it.

Abstract: A method of and apparatus for sampling granular material where a substantially vertical sampling tube is subjected to axial, and/or rotational oscillations to reduce the vertical vector component of the friction force between the granular material and the tube to be substantially equal to the weight of an elemental disc of the material in the sampling tube. The acceleration force on the disc is substantially zero and the material has no pressure gradient or bulk density gradient.