A processing apparatus (10) has chambers (11 and 12) and a loading mechanism (13) for transferring workpieces into and out of the chambers. The workpieces are carried on a pallet (16) which is slotted so that, when it is inserted into the chambers (11 or 12) the slots are aligned with lines A-H on lifting pins. This arrangement enables the mechanism (13) to withdraw the pallet, whilst the pins (22) are in their erect position.
