Patent ID: 7775042

Claim:
An engine for generating motion from a cool region that is proximal to but separated from a warm region said cool region and said warm region defining a temperature range, said engine comprising: (a) an article of phase change material having a phase transition within said temperature range and an assembly of elements; (b) a shuttle of thermal insulating material, adapted to be placed in a first position adapted to expose said article of phase change material to said cool region while insulating said article from said warm region, and alternately placed in a second position adapted to expose said article to said warm region, while insulating said article from said cool region, said shuttle having a third position between said first position and said second position, wherein said article is insulated from both said cool region and said warm region; (c) a shuttle movement assembly, adapted to move said shuttle to said third position when a cool to warm phase transition is well underway and to said first position to expose said article to said cool region after a cool to warm phase transition is substantially complete, and to move said shuttle to said third position when a warm to cool phase transition is well underway and to said second position so as to expose said article to said warm region after a warm to cool phase transition is substantially complete.