Abstract: A locking/unlocking mechanism for headrest, provided in a headrest holder in which a headrest stay of the headrest is slidably inserted, which comprises: a lock element having a hole; a biasing element; and an unlocking hole formed in the headrest holder. The lock element is movable between a locking position for engagement with a stopper notch formed in the headrest stay and an unlocking position for disengagement from the stopper notch. The lock element is normally biased by the biasing means in a direction to the locking position. When the lock element is set in the unlocking position, an unlocking tool can be inserted in the unlocking hole of headrest holder and engaged in the hole of lock element so as to retain he lock element in the unlocking position, whereby the headrest can be easily removed from the headrest holder.

Abstract: A locking/unlocking mechanism for headrest, provided in a headrest holder in which a headrest stay of the headrest is slidably inserted, which comprises: a lock element having a hole; a biasing element; and an unlocking hole formed in the headrest holder. The lock element is movable between a locking position for engagement with a stopper notch formed in the headrest stay and an unlocking position for disengagement from the stopper notch. The lock element is normally biased by the biasing means in a direction to the locking position. When the lock element is set in the unlocking position, an unlocking tool can be inserted in the unlocking hole of headrest holder and engaged in the hole of lock element so as to retain he lock element in the unlocking position, whereby the headrest can be easily removed from the headrest holder.

Abstract: This invention relates to an apparatus for thermal diffusion by means of high frequency induction heating suitable for mass production of semiconductor substrates of uniform quality; wherein a plurality of heating bases, each made of a material having good electric conductivity, and carrying semiconductor substrates, are continuously fed through a furnace tube where the bases are heated by means of high frequency wave excitation in order that each semiconductor substrate receives substantially the same thermal treatment.