Non-constant controls with photoelectric switches

Claim 1

A CONTROL SYSTEM FOR REGULATING A PREDETERMINED CONDITION COMPRISING FIRST MEANS FOR CHANGING SAID CONDITION, CONTROL MEANS OPERATIVELY CONNECTED WITH SAID FIRST MEANS TO REGULATE CHANGES IN SAID CONDITION AND INCLUDING PHOTOELECTRIC MEANS, SAID CONTROL MEANS PROVIDING REGULATION OF SAID FIRST MEANS IN RESPONSE TO CHANGES IN ILLUMINATION OF SAID PHOTOELECTRIC MEANS, LIGHT SOURCE MEANS PROVIDING A LIGHT BEAM FOR ILLUMINATING SAID PHOTOELECTRIC MEANS, SECOND MEANS RESPONSIVE TO CHANGES IN SAID CONDITION FOR VARYING THE ILLUMINATION OF SAID PHOTOELECTRIC MEANS BY SAID LIGHT SOURCE MEANS, THIRD MEANS LOCATED BETWEEN SAID LIGHT SOURCE MEANS AND SAID SECOND MEANS FOR PERIODICALLY VARYING THE ILLUMINATION OF SAID PHOTOELECTRIC MEANS BY SAID LIGHT SOURCE MEANS BY EFFECTIVELY CHANGING THE CROSS SECTION OF SAID LIGHT BEAM ONLY TO SUCH AN EXTENT THAT A PORTION OF SAID LIGHT BEAM ALWAYS REACHES SAID SECOND MEANS, AND MEANS TO PROVIDE CONCURRENT OPERATION OF BOTH SAID SECOND AND THIRD ILLUMINATION VARYING MEANS TO SUPERIMPOSE THEIR ILLUMINATION VARYING EFFECT ON SAID PHOTOELECTRIC MEANS TO PROVIDE REGULATION OF SAID CONDITION.