Door mechanism

Claim 1

IN AN ENCLOSURE UTILIZED IN THE CONTROL OF AMBIENT ATMOSPHERIC CONDITIONS IMMEDIATELY SURROUNDING PROCESSING MACHINERY, A ROOF COVERING SAID MACHINERY, SIDE PANELS EXTENDING DOWNWARDLY FROM SAID ROOF AND TERMINATING SHORT OF THE FLOOR TO FORM AN APERTURE SUBSTANTIALLY COEXTENSIVE WITH SAID SIDE PANELS, GUIDE ROD SUPPORT MEANS MOUNTED ON SAID SIDE PANELS INSIDE SAID ENCLOSURE AND EXTENDING DOWNWARDLY FROM NEAR SAID ROOF TO THE LOWER EDGE OF SAID SIDE PANELS, GUIDE RODS MOUNTED ON EACH OF SAID SUPPORT MEANS, DOOR MEANS OPERABLE TO CLOSE SAID APERTURE, UPWARDLY EXTENDING ARMS ON SAID DOOR MEANS HAVING GUIDE BUSHINGS THEREON WHICH SLIDE ON SAID GUIDE RODS TO RESTRICT MOVEMENT OF SAID DOOR MEANS, A FLUID MOTOR OPERABLE TO MOVE SAID DOOR MEANS BETWEEN A LOWERED AND A RAISED POSITION, VALVE MEANS FOR CONTROLLING THE OPERATION OF SAID MOTOR, CONTROL RELAY MEANS, MANUALLY ACTUATED SWITCH MEANS BIASED TO AN OPEN POSITION AND OPERABLE WHEN CLOSED TO ACTUATE SAID CONTROL RELAY MEANS, A HYDRAULIC PUMP ACTUATED IN RESPONSE TO ACTUATION OF SAID CONTROL RELAY MEANS FOR GENERATING A PRESSURIZED FLUID, MEANS FOR POSITIONING SAID VALVE MEANS TO CONDUCT SAID PRESSURIZED FLUID TO SAID MOTOR IN RESPONSE TO ACTUATION OF SAID CONTROL RELAY MEANS TO EFFECT MOVEMENT OF SAID DOOR MEANS TOWARD EITHER OF SAID POSITIONS, A TIMER RELAY ACTUATED BY SAID CONTROL RELAY MEANS, AND A TIMER SWITCH MOUNTED IN A CIRCUIT IN SERIES WITH SAID MANUAL SWITCH MEANS AND ACTUATED BY SAID TIMER RELAY TO MAINTAIN A CIRCUIT TO SAID CONTROL RELAY MEANS WHEN SAID MANUAL SWITCH IN RELEASED, SAID TIMER RELAY BEING OPERABLE AFTER THE EXPIRATION OF A PREDETERMINED AMOUNT OF TIME TO OPEN SAID TIMER SWITCH TO INACTIVATE SAID CONTROL RELAY MEANS.