Abstract: A multipurpose exercise machine comprising a compact movable frame, a large diameter pulley and a plurality of novel low friction vacuum springs for generating a force is disclosed. The vacuum springs are comprised of two rigid end pieces that are movable relative to each other. A flexible membrane couples the two rigid end pieces to each other and encloses a hermetically sealed region in between the movable bodies and the flexible membrane. A user operating the machine exerts a force that pulls the two end pieces are apart which forms a vacuum that opposes the motion.

Abstract: A multipurpose exercise machine comprising a compact movable frame, a large diameter pulley and a plurality of novel low friction vacuum springs for generating a force is disclosed. The vacuum springs are comprised of two rigid end pieces that are movable relative to each other. A flexible membrane couples the two rigid end pieces to each other and encloses a hermetically sealed region in between the movable bodies and the flexible membrane. A user operating the machine exerts a force that pulls the two end pieces are apart which forms a vacuum that opposes the motion.

Abstract: A heat engine of the rotary vane type and thermodynamic cycle is disclosed. The engine converts thermal energy contained within relatively low temperature hot gasses into mechanical energy. The engine operates by expanding a hot gas to a sub-atmospheric pressure, cooling the gas at a roughly constant volume and then cooling the gas further while compressing it back to atmospheric pressure. Possible sources of hot gasses for powering the engine include exhaust gasses from other engines and air heated by solar collectors. A novel compressor and expander comprised of the primary components of the engine is also disclosed.

Abstract: A heat engine capable of significantly higher thermal efficiencies than existing heat engines operating within the same temperature ranges, wherein the heat engine can operate efficiently as either a forward heat engine or as a reverse heat engine at any given selected moment; thus, permitting the present heat engine to be utilized as an air conditioner or heat pump, or, alternatively, if a heat source is provided to the engine, as a forward heat engine producing a work output.