Positive backing sheet plate lock-up

Claim 1

A saddle lock-up for flexible printing plates comprising: a semi-cylindrical saddle body having a leading edge and a trailing edge; leading edge clamping means connected to said leading edge to positively secure one end of a flexible printing plate; trailing edge clamping means moveably connected to said trailing edge to move toward and away from said trailing edge to positively secure the other end of a printing plate, said trailing edge comprising a transverse U-channel parallel and adjacent to said trailing edge of said saddle, a slide bar transversely slideably mounted within said U-channel, said slide bar and said U-channel defining a gap therebetween for one end of a printing plate, said slide bar having camming surfaces thereon on the side opposite said gap and having printing plate gripping means on the side within said gap, and cam adjustment members connected to said U-channel through the side of said U-channel, said cam adjustment members engaging said camming surfaces to move said gripping means within said U-channel to close said gap and positively clamp a flexible printing plate; and resilient means biasing said trailing edge clamping means away from said trailing edge to tension a flexible printing plate when clamped.