Are perpetual motion machines patentable?
The short answer is 'no'.
Perpetual motion machines allegedly produce endless motion without any external source of energy. However, all machines naturally lose energy due to friction, heat, and sound. Therefore, no machine can be 100% efficient and run perpetually.
In practice, perpetual machines are impossible to build. They do not work.
Therefore, the Patents Offices can reject such applications on the grounds that the claimed invention does not achieve the use promised by the patentee in the specification, and have a credible use.
Subsection 18(1) of the Australian Patents Act 1990 requires that an invention must be useful in order to be patentable. Section 7A of the Patents Act states that ‘an invention is taken not to be useful unless a specific, substantial and credible use for the invention (so far as claimed) is disclosed in the complete specification’.
A case in point is the standard patent application (number 2011201103) for an "Energy Generation Device" by Mr Salvator Spataro. The Examiner rejected this application on he grounds that:
"The claimed invention does not achieve the use promised by the patentee in the specification, and have a credible use. The claimed invention is not useful for energy generation but merely wastes energy. For the cycle to run continuously, firstly by taking into account the energy needed for the pump (14), solenoid arms of the lift mechanism (16), shutters (27) and barrier door (32) to operate as stated in the specification the device will require more energy to run the cycle in the device than the energy extracted by the shaft (29) and gear system (19) through the generator (18) of the device. There also exists friction losses in the star wheels and the gear system and also viscous drag when the buoyant member is moving in the fluid filled first passage. Hence for the given system W in > W out (W is work). Therefore I fail to see how this device will produce excess useful work to be used as energy for the reasons given above. It is also noted that the device contradicts known physical laws (i.e. Second Law of Thermodynamics)."