Patent ID: 7370895
Filing Date: 2008-05-13
Classification: H01L,Y10S

Abstract:
1. A work transfer device, comprising: a vacuum holding mechanism for holding a frame on which work is mounted, said holding mechanisms having a plurality of arms with vacuum pickups at an end area of each arm; sensor means for detecting a vacuum pressure value in the vacuum pickups; and a plurality of frame clamps and clamp actuators for moving the clamps between a extended position near a bottom surface of the frame when the frame is held by the vacuum pickups and a retracted position away from the bottom surface of the frame when the frame is released from the vacuum pickups; wherein each of the frame clamps is mounted to a respective one of the vacuum pickups, and wherein the clamp actuators are operative for moving the clamps into their extended position in response to the sensor means detecting a vacuum pressure value in the vacuum pickups above a predetermined value indicative of the frame being securely held and are operative for moving the clamps into their release position in response to the sensor means detecting a vacuum pressure value in the vacuum pickups below a prescribed value indicative of the frame having been released by the vacuum pickups.