| 摘要 |
A workpiece is placed on a plurality of supporting cylinders which are projected upwardly from an upper plate or a hollow table body. All of the supporting cylinders normally assume a lowered position at which lower end faces thereof contact seat portions in a chamber of the table body so that attracting pads provided at upper ends of the supporting cylinders are disconnected from the chambers. Accordingly, even if the chamber is put into a negative pressure condition, the workpiece is not attracted to the attracting pads. Then, compressed air is supplied to the pneumatic cylinders of those supporting cylinders which fall within a horizontal area of the workpiece to lift those supporting cylinders. Consequently, the lower end faces of those supporting cylinders are spaced away from the seat portions to allow communication between the attracting pads and the chamber by way of air sucking passageways formed in the supporting cylinders to suck air through the attracting pads. As a result, the workpiece is attracted to the attracting pads and thus fixed to the lifted supporting cylinders. |
