PURPOSE: To prevent the breakage of piezo-electric elements during action by setting up the plate thickness of first and third hinges of larger distance to greater one than that of other hinges.
CONSTITUTION: The distance L1 between hinges 5 and 6 connected to a lever 11 is made greater than that L2 between hinges 7 and 8 connected to a lever 12. The plate thickness d1 of the hinge 6 is also made greater than that d2 of the hinge 7 according to the difference between the distances L1 and L2. When the length of a piezo-electric element 2 is increased and a dimensional strain is produced during the driving period, a fitting part 9 is pushed up correspondingly, and turning actions directed to broken line arrows E and G occur in the levers 11 and 12. Since L1>L2, the bending ratio of the hinge 6 becomes smaller than that of the hinge 7. Both reactions are mutually offset and therefore, the horizontal reaction acting on the fitting part 9 is almost zeroed, and thereby bending moment to be given to the element 2 is relieved to prevent the breakage of the element 2.
FUKUI IZUMI
YANO TAKESHI
Next Patent: STORAGE DEVICE FOR ON-VEHICLE ELECTRICAL EQUIPMENT