Patent attributes
A closure device for a prison or hospital door having an access opening therethrough enables articles to be passed through the door without endangering the guard or hospital worker delivering the articles. The closure device includes a rectangular box having a top surface formed with a transparent panel, a hinged front access door, a vertically slidable rear access gate and an actuation mechanism for controlling the movement of the gate. The actuation mechanism has a pivoted actuator handle coupled to the rear gate to affect vertical movement thereof and a spring-loaded supplemental lock that requires release against a lock bar secured to the rear gate before the actuator handle can be moved. The rectangular box can have two opposing side walls or be formed with an open side that closes against a cover member secured to the door frame to close the open side of the box.
