Patent ID: 7262389

Claim:
An apparatus for forming bag edges in a layered plastic film, comprising: a frame; a kinematic linkage supported by the frame; a pair of laterally spaced apart clamps carried for reciprocation by the kinematic linkage relative to the frame and configured to cooperatively clamp plastic film alone a clamp plane during sealing and severing; a heated seal bar carried for reciprocation by the kinematic linkage relative to the frame along a sealing plane between the clamps and substantially perpendicular to the clamp plane, the seal bar having a nip edge configured to seal and sever bag edges in layered plastic film; and a seal bar anvil carried for reciprocation by the kinematic linkage relative to the frame along the sealing plane, the seal bar anvil having a resilient tube configured to deform as the seal bar is driven into the tube to seal and sever a bag edge therebetween; wherein the kinematic linkage is operative to sequentially: 1) reciprocate the clamps to hold layered plastic film along the clamp plane, 2) reciprocate the seal bar and the anvil into forcible engagement with opposed faces of the layered plastic film, and 3) reciprocate the anvil and the seal bar to move the seal bar beyond the clamp plane so as to stretch the film away from the clamp plane during further sealing and severing.