Visual acuity projector with electric motor control for film chart and rotary astigmatic test element

Claim 1

IN VISUAL ACUITY PROJECTION APPARATUS, THE IMPROVEMENT COMPRISING: (A) A PROJECTOR ADAPTED TO RECEIVE A FILM CHART NORMALLY MOVABLE IN A VERTICAL PLANE ACROSS THE LIGHT BEAM FROM THE PROJECTOR BETWEEN PREDETERMINED LIMITS OF TRAVEL; (B) A FILM CHART FOR USE WITH SAID PROJECTOR HAVING A ROTATING ASTIGMATIC ELEMENT ROTATING BETWEEN PREDETERMINING LIMITS CONTAINED THEREIN OPERABLY CONNECTED TO A CONTROL ELEMENT DISPOSED AT THE UPPER EXTREMITY OF SAID FILM CHART AND HAVING A SWITCH ENGAGING PORTION AT THE LOWER EXTREMITY THEREOF; (C) ELECTRICAL DRIVING MEANS INCLUDING AT LEAST ONE REVERSIBLE MOTOR CARRIED BY SAID PROJECTOR AND ADAPTED TO BE CONTROLLED ELECTRICALLY; (D) POWER CONNECTING MEANS CONSTRUCTED AND ARRANGED TO CONNECT SAID CONTROL ELEMENT OF SAID FILM CHART TO SAID ELECTRICAL DRIVING MEANS; (E) BRACKET MEANS CONNECTED TO SAID PROJECTOR FOR SUPPORTING SAID POWER CONNECTING MEANS, ONE OF SAID MEANS MOVING BETWEEN A FIRST POSITION WHERE SAID FILM CHART CONTROL ELEMENT IS NORMALLY ENGAGED BY SAID POWER CONNECTING MEANS AND A SECOND POSITION WHERE SAID POWER CONNECTING MEANS IS OPERATIVELY DISENGAGED; (F) RESILIENT MEANS CONTINUALLY URGING ONE OF SAID MEANS TOWARDS SAID FIRST POSITION BUT ALLOWING SAID MEANS TO MOVE TO ITS SECOND POSITION; (G) POWER TRANSLATING MEANS DRIVABLY CONNECTED BETWEEN SAID FILM CHART AND SAID ELECTRICAL DRIVING MEANS FOR VERTICALLY MOVING SAID FILM CHART; (H) SWITCH MEANS CONNECTED TO SAID ELECTRICAL DRIVING MEANS AND DISPOSED IN OPERABLE RELATION WITH THE SWITCH ENGAGING PORTION OF SAID FILM CHART FOR DISABLING THAT POWER WHICH IS APPLIED TO SAID POWER TRANSLATING MEANS TO STOP THE DOWNWARD MOVEMENT OF SAID FILM CHART WHEN SAID ROTATING ASTIGMATIC ELEMENT IS IN THE PROJECTION LIGHT PATH; (I) AND CONTROL MEANS ELECTRICALY CONNECTED TO SAID ELECTRICAL DRIVING MEANS FOR CONTROLLING THE VERTICAL MOVEMENT OF SAID FILM CHART AND THE MOVEMENT OF SAID ROTATING ASTIGMATIC ELEMENT CONTAINED THEREIN.