Patent ID: 7204179

Claim:
A shear assembly for a roll forming machine which forms an indeterminate length panel having a desired lateral profile, comprising: a blade assembly including a pair of side-by-side co-planar blade members separated along a generally straight line; and an actuator mechanism for said blade assembly operative to move said pair of blade members (a) in a first phase of parallel movement along said straight line, (b) followed by a second phase of outward pivoting movement wherein the leading ends of said pair of blade members move away from each other, and (c) followed by a third phase of outward pivoting movement wherein the tail ends of said pair of blade members move away from each other; wherein said actuator mechanism includes: a block movable along said straight line; a pair of link members each pivotally connected at a first end to said block and at a second end to the tail end of a respective one of said blade members; a first guide mechanism operative to (a) constrain movement of the leading ends of said blade members during said first phase to movement along said straight line, (b) force the leading ends of said pair of blade members to separate during said second phase, and (c) prevent further movement of the leading ends of said pair of blades along said straight line during said third phase; and a second guide mechanism operative to (a) constrain movement of the tail ends of said blade members during said first phase to movement along said straight line, (b) constrain movement of the tail ends of said blade members during said second phase to movement along said straight line, and (c) allow the tail ends of said pair of blade members to separate during said third phase.