| 摘要 |
A sheet of glass on a platform is centered by a plurality of pins around the periphery thereof. Drive mechanism for the pins moves a pin-carrying support from a rest position in which the pin is turned down below the plane of the sheet and retracted from the sheet to an upright working position in which the pin is advanced into engagement with the sheet, and vice versa. Means are provided for guiding the pin-carrying support during the movements thereof, and adjustable stop means limits the advance. |
