Renewable Thermodynamics, LLC

Richard J Ide

Gary P Hoffman

Nanette F Ide

An externally heated engine is provided which has a piston and a displacer. The position of the piston can be adjusted by a yoke and disk assembly on one end of a link and spacers and gaskets in the cylinder. The relative position of the displacer with respect to the piston can be changed by changing the relative position of a pair of disks in the crankshaft assembly. The displacer is caused to reciprocate by a link which is moved by a displacer cam assembly. The displacer cam assembly includes a first cam and a second cam. The first cam and the second cam each have a groove path. The displacer link follows the groove path of the cams to cause the displacer to dwell at the two ends of its stroke and to move rapidly from one end to the other.

Externally heated engine

The laser lawn cutting system of the present invention consists of an array or grid of laser heads distributed across a lawn. The laser heads may be permanently fixed above the surface of the lawn, or preferably mounted underneath the surface of the lawn and designed to pop up at the time of cutting. If mounted underneath the surface of the lawn, solenoids may be used to move the laser heads above the surface. Other mechanical devices could also be used to cause the laser heads to move above the surface of the lawn. Preferably, the laser heads will be distributed across the lawn in a grid or matrix, such that the laser light generated by the rotating laser head sweeps across the lawn in overlapping arcs to cut the vegetation. The system may also be used to melt snow or kill insects.

Apparatus and method for cutting lawns using lasers

An externally heated engine is provided which has at least two pistons. The first piston has a first side (working side) and a second side opposite the first side. The first side of the first piston and the first cylinder define a first working chamber containing working fluid. The second side of the first piston and the first cylinder define a first opposite chamber containing an opposing fluid. A heater heats the working fluid in the first cylinder. Preferably, the cylinder is heated by a heat source so that the working fluid has a temperature of no more than 500&#xb0; Fahrenheit with a temperature difference between the heat source and the working fluid of less than 5&#xb0; Fahrenheit. The second piston reciprocates within a second cylinder, and has a first side (working side) and a second side opposite the first side. The first side and the cylinder define a working chamber containing working fluid. The second side of the piston and the cylinder define a second opposite chamber containing an opposing fluid. The working fluid in the second cylinder is cooled to a temperature of below 35&#xb0; Fahrenheit.

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Middlesex, NY, United States of America

Richard J Ide