Patent Publication Number: US-4650987-A

Title: Chest for the storage of light sensitive film material or paper

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention concerns a chest for the storage of light sensitive film material or paper, which may be opened only under dark room light. The invention is to prevent the unintentional opening of the film chest in the dark room under a bright or normal light and thus the preexposure of the film or paper material. 
     2. Background of the Art 
     Film chests or cabinets are not secured and therefore may be opened even under a bright light. It is known to place these film chests or cabinets in dark rooms. The security of the entry door of the dark room is often insufficient as the film chests and cabinets may be opened under bright lights. Thus valuable film material is frequently preexposed and destroyed. A known apparatus to prevent the unintentional exposure of photo material involves a light trap in the form of a service hatch to be set into a wall opening. Even though two interlocking covers are present, their true function, i.e. to prevent unintentional exposure, may be overlooked. 
     SUMMARY OF THE INVENTION 
     This problem is overcome by the chest of the instant invention wherein a photosensitive cell is built into the chest or cabinet and adjusted so that the locking of the chest or cabinet is effected by means of a solenoid. The solenoid permits the chest or cabinet to be opened only if the prevailing light is less than the preset luminous intensity (lux). 
     In a further development of the invention, the chest is equipped with an opening flap which is fastened by means of special hinges to the upper edge of the chest and may be opened only far enough so that it will close by its own weight after opening. 
     Light sensitive film material such as photographic film and x-ray film may be stored safely in the chest or cabinet of the invention without an unintentional opening of the chest or cabinet. Unintentional preexposure of the material is therefore prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING OF THE INVENTION 
     An advantageous embodiment of the invention is described with reference to the drawing. The apparatus illustrated comprises a chest into which for example unexposed x-ray films may be placed in an arrangement according to size. 
    
    
     DETAILED DESCRIPTION OF THE DRAWING 
     Careless opening of the cover 6 that may be flipped upwards by means of the hinge 2, would render the stock of valuable x-ray films useless. The cover is therefore equipped with a locking projection 1 which in the closed state of the cover may be locked by means of the solenoid 5 located in the housing to block the cover. Only in the case of an adequately low environmental luminosity does the photocell 4 built into the housing provide an electric current weak enough so that it leads by means of an appropriate electric circuit to an actuation of the magnet and the unlocking of the cover. The symbol 3 designates a switch to affect the functioning of the magnets below a certain luminosity through electronic means, i.e. the magnet responds to the pressure of the switch and opens the lock. In case of a luminosity higher than desired, the solenoid remains without current and the lock is not eliminated by pressing the switch. 
     The hinge 2 of the chest like apparatus has the characteristic that it may be raised only to the extent whereby it drops back into its closed state automatically when released. The layout is further such that the solenoid locks the cover normally and until actuated by a low light condition sensed in the photocell and transmitted electrically, so that the cover cannot be opened carelessly even in the case of a power failure.