40 Inventive Principles
Flexible Shells and Thin Films

a) Replace traditional constructions with those made of flexible shells or thin films.

b) Isolate the object from its environment using flexible shells or thin films.

  1. The “Harmonic Drive“ gear has a flexible toothed gear shell. Apart from having a very high gear ratio with only a single transmission, this solution also allows motion to be transmitted through a hermetic wall.
  2. Gases can be separated using thin films, which allow some molecules to pass better than others. (US Pat. 4239506).
  3. Piezoelectric foils made of e.g. polypropylene or polyester are used in acoustics (ultrasound-detectors, echo depth sounder, probes for medical echograms), as pressure transducers (acceleration meter, keyboards, non-destructive material testing, measuring the distribution of compression on surfaces) or as oscillators/vibrators (lightweight headsets, protection of ships’ hulls against marine infestation).