Abstract: The present invention provides heat exchanging elements for use in Stirling engines. According to the present invention, the heat exchanging elements are made from muliple platelets that are stacked and joined together. The use of platelets to make heat exchanging elements permits Stirling engines to run more effiecient because the heat transfer and combustion processes are improved. In one embodiment, multi-stage combustion can be introduced with platlets, along with the flexibility to use different types of fuels. In another embodiment, a single component constructed from platelets can provide the heat transfer rquirements betweeen the combustion gas/working gas, working gas in the regenerator and the working gas/coolant fluid of a Stirling engine. In another embodiment, the platelet heat exchanging element can recieve solar energy to heat the Stirling engine's working gas. Also, this invention provides a heat exchanging method that allows for multiple fluids to flow in opposing or same direction.

Abstract: An intercom system for use with a plurality of telephones on a single extension includes a single master station and a plurality of slave stations. The master station is connected so as to interrupt the telephone line pair to and from a central exchange. Each slave station is preferably associated with a handset that is on the extension. When the extension is not being used for intercom service or for an outside call, any telephone handset on the extension that has a keypad can initiate a signal that is received and decoded in the master unit. When the master station receives such a signal, it disconnects the line to the telephone exchange from the extension and connects the telephone exchange to a circuit that detects incoming calls so that they can be signaled to users. The master station also sends a signal to each slave station that enables the intercom function.

Abstract: An elongated lightweight exercise device employed by the user to build and strengthen the muscles in the arms and chest area, comprising a short straight section of helically wound cable and two handles, one disposed at each end thereof. The wire rope may be coated with synthetic resinous material. Each handle comprises a hand-width long section of pipe enveloped by a plastic or foam grip with which to grasp the device, and a flexible strap with ends rotatably attached to each end of the pipe section in looped relation to the associated handle. To operate, the user inserts his hands through the straps and firmly grasps the plastic handle grips. Two equal and opposite inward forces are exerted on the handles by the user which causes the cable to bow under flexure stress. The user then allows the cable to return to its resting position due to the memory of the cable and repeats the procedure as appropriate. Repeated flexure over an indefinite interval of time does not incite fatigue in the cable.