Abstract: A power transmission device has a primary driven gear and a scissor gear arranged abreast in a superimposed manner concentrically with the primary driven gear so as to be shiftable from it. Both the gears have plural pairs of openings superimposable to each other, so that each pair of the openings form an opening space. In each opening window a damper spring is provided and compressed so that the spring's ends press both edges of the opening space, with the spring's side portions engaged with the side face of the rotor so that one or both the primary driven gear and scissor gear, are resiliently coupled with the rotor by way of the damper springs.

Abstract: An electronic mail system for transmitting a voice message from a telephone to a mail terminal equipment using an electronic mail, a destination identifier and a voice message are inputted from the telephone. A voice signal is generated in correspondence to the voice message and the destination identifier and the voice signal are transmitted from the telephone to a transceiver apparatus via a telephone line network. In the transceiver apparatus, a voice file is produced from the voice signal received from the telephone via the telephone line network and then the electronic mail is produced from the voice file and the destination identifier. The electronic mail is transmitted to the mail terminal equipment having a voice output function via a local area network (LAN). The mail terminal equipment reproduces the voice message from the voice file of the electronic mail using the voice output function.

Abstract: An inexpensive Love-wave device having a wide frequency difference between its resonant and antiresonant frequencies includes a Y-cut substrate made from LiNbO.sub.3 for X propagation. An interdigital transducer including a thin film of Ta or W is located on the substrate for exciting a Love wave.

Abstract: A method of manufacturing a surface wave device of an end-face reflection type comprising forming an IDT 12 on a piezoelectric plate 11, and cutting the piezoelectric plate 11 in a direction which is parallel to the outermost electrode fingers of the IDT within a target area which extends from the out edges of the outermost electrodes to a position .lambda./8 outwardly therefrom, .lambda. being the wavelength of the surface wave generated by the IDT, so as to form opposite end faces of the surface wave device.

Abstract: A surface wave resonator suitable for use in the frequency band range of about 70 to 200 MHz has a wide frequency band characteristic. The resonator is a free edge reflective-type surface wave resonator having a pair of comb-like electrodes formed on the upper surface of a piezoelectric substrate made of 41.degree. Y-cut X propagating piezoelectric single crystals of LiNbO.sub.3, wherein SH-type leaky waves are reflected between two opposing free edges of the resonator.

Abstract: Disclosed herein is a surface wave device utilizing Love waves, which comprises an LiNbO.sub.3 single-crystalline substrate (2), at least one interdigital transducer (5) formed thereon and a ZnO thin film (6) formed to cover the interdigital transducer (5). Assuming that H represents the thickness of the ZnO thin film and .lambda. represents the wavelength of the as-excited Love waves, a ratio H/.lambda. is set in a range of 0.01 to 0.2.