Safety device for the closing edge of a door leaf

A safety arrangement for a motor driven door or gate to close building entrances or doorways, comprising:

• a vertical movable overhead door of at least one part;
• a closing edge at a terminal end of said door;
• an elastically deformable hollow rubber section at said closing edge and having an interior hollow space with first and second ends;
• an air pressure-wave receiver signal transformer connected to said first end of said hollow space through a first tubular member;
• an air pressure-wave transmitter connected to said second end of said hollow space through a second tubular member;
• said transmitter generating a continuous air pressure oscillation having a first pulse duration and a first pulse frequency when said closing edge is freely movable through the entire path of motion of said door, said continuous oscillation having a second pulse duration differing from said first pulse duration and a second pulse frequency differing from said first pulse frequency when said closing edge abuts an object positioned in said path of motion of said door, said oscillation being continuously generated by said transmitter and continuously received by said receiver to monitor continuously said closing edge and detect when said closing edge abuts said object for stopping thereupon movement of said door;
• said transmitter comprising a rhythmically driven air volume displacer, a transmitter pressure chamber connected to said volume displacer for alternatingly and rhythmically increasing the volume of said pressure chamber, said pressure chamber communicating with said second tubular member;
• said volume displacer comprising a pulsatingly-driven piston pump;
• said air pressure wave transmitter having electromagnetic driving means with an electrical input and mechanical output, said mechanical output being selectively dependent on frequency and amplitude of said electrical input;
• said mechanical output having a pulsatingly-driven output member with an armature movable translationally;
• said electromagnetic driving means comprising an electrical motor with an output shaft, and a driven eccentric member on said output shaft;
• said receiver signal transformer comprising an air pressure feeler controlled by air pressures on said first end of said hollow space, a receiving pressure chamber connected to said air pressure feeler and communicating with said hollow space through said first tubular member;
• said air pressure feeler comprising a piston pump with an output member, and a signal modulator driven by said output member;
• said receiver signal transformer having selectively amplitude and frequency analyzing means with a secondary discriminating circuit, said analyzer having an output for controlling driving of said door or gate;
• said air pressure-wave transmitter having a switching-on input, and feed drive control of said door or gate connected to said switching-on input;
• said first pulse duration being shorter than said second pulse duration.