Abstract: A stacker crane, which retrieves cases from shelves and conveys the same, includes a traveling cart, a mast, a lift platform, a slide fork, and a cover. The cover is made of a flame retardant or non-inflammable material, and is supported in a detachable manner so as to move toward the top surface of the slide fork.

Abstract: A small and easily produced piezoelectric resonator, which effectively damps unwanted vibration and utilizes intended vibration includes excitation electrodes provided on both main surfaces of a piezoelectric substrate, and first and second lead-out electrodes and first and second terminal electrodes electrically connected to the excitation electrodes, respectively. At least one of the terminal electrodes includes an electrode extension portion arranged to extend into the imaginary region where the first and second excitation electrodes are extended to at least one of the side edges of the piezoelectric substrate.