Abstract: A push-button switch and a teaching pendant employing the same are provided. The push-button switch ensures that a push button is capable of switching ON/OFF the switch if one of contacts thereof should fail during an operation of the switch. For achieving this object, a switch case 3 contains two c-contacts 9a, 9b each having a snap action configuration and switching mechanisms 11a, 11b for opening/closing the c-contacts 9a, 9b. When a push button 5 is depressed, the switching mechanisms 11a, 11b simultaneously open/close the c-contacts 9a, 9b for turning ON/OFF a push-button switch 1.

Abstract: An actuator of the present invention comprises an operation key 2 to be inserted into a key insertion hole formed in the safety switch, and a base 3. The operation key 2 is held on the base 3 and capable of freely swinging in two orthogonal directions. The actuator also comprises means (e.g. a guide stopper 4 and engagement spaces 34) for selectively restricting the swinging movement of the operation key 2 to either of the two directions.

Abstract: A novel and useful linear triene compound represented by the following formula (1) is co-polymerized with an &agr;-olefin to obtain an ethylenically unsaturated copolymer which is superior in weather-ability, heat resitance and fastness to ozone, together with superior scorch stability and vulcanizability at high velocity in which R1, R2, R3, R4, R5 and R6 stand each, independently of each other, for hydrogen atom or an alkyl having 1-3 carbon atoms, R7 represents an alkyl having 1-3 carbon atoms and n is an integer of 0-5, with the proviso that each of R4s or of R5s may be identical with or different from each other, respectively, when n is 2 or greater.