Slat lock assembly for portable screens

Claim 1

A PORTABLE PROJECTION SCREEN ASSEMBLY COMPRISING A VERTICAL COLUMN HAVING STAND MEANS AT ITS LOWER END, ELONGATED HOUSING MEANS CARRIED BY SAID COLUMN FOR MOVEMENT FROM STORAGE POSITION TO OPERATING POSITION, A ROLLER CARRIED BY AND MOUNTED AT ITS ENDS IN SAID HOUSING MEANS, A SCREEN WOUND UPON SAID ROLLER AND AFFIXED TO SAID ROLLER AT ON END THEREOF, A SUPPORTING SLAT AFFIXED TO THE OTHER END OF SAID SCREEN, SAID ROLLER BEING BIASED TO ROLL UP SAID SCREEN TO ROLLED UPON POSITION BUT PERMITTING SAID SCREEN TO BE UNROLLED TO UNROLLED POSITION, EXTENSIBLE MEANS FOR SUPPORTING SAID SCREEN IN UNROLLED POSITION, AND SLAT LOCK MEANS MOVABLY CARRIED ON SAID HOUSING MEANS AND BIASED FROM SLAT ENGAGING POSITION, SAID SLAT LOCK MEANS BEING OPERATIVE IN RESPONSE TO MOVEMENT OF SAID HOUSING MEANS WITH RESPECT TO SAID VERTICAL COLUMN FOR AUTOMATICALLY ENGAGING AND HOLDING SAID SUPPORTING SLAT AND THEREBY PREVENTING UNROLLING OF SAID SCREEN WHEN SAID HOUSING MEANS ARE MOVED FROM OPERATING POSITION TO STORAGE POSITION.