Device for detecting the loss of tension of a warp yarn in a weaving loom

A device for detecting the loss of tension of a warp yarn in a weaving loom with at least two heddle frames which alternatively move up and down, comprising:

• at least two switching means for detecting a lower position of a corresponding heddle frame, by passing an electric current therethrough;
• an upper heddle bar fixedly connected to said each heddle frame, said upper heddle bar including a plurality of first electro-conductive portions insulated from each other, each of said first electro-conductive portions being so arranged on said upper heddle bar that the entire length of said upper heddle bar is electrically divided into a plurality of portions, and a longitudinal second electro-conductive portion which extends along said upper bar, means insulating said second electro-conductive portion from said first electro-conductive portions, means for connecting said second electro-conductive portion electrically to said switching means;
• a plurality of heddles, each of said heddles having upper and lower loops at both ends thereof, said upper and lower loops being loosely coupled to said upper heddle bar and a lower heddle bar of the each heddle frame respectively, the upper loop being made of an electro-conductive material, each heddle assuming an upper position with respect to the upper heddle bar when normal tension of a warp connected to the heddle is provided to the heddle for pushing up the same during which the heddle bar is at a lower position thereof, each said heddle assuming a lower position when the tension of said warp is lost during which said heddle bar is at the lower position thereof, said upper loop of a heddle being spaced from said first electro-conductive portion when the heddle assumes an upper position, said upper loop of a heddle being disposed for coming into contact with said first and second electroconductive portions of said upper heddle bar when the heddle assumes a lower position;
• and
• display means including a plurality of electrical circuitry respectively connected to each of said first electro-conductive portions for indicating a portion of a heddle bar to which a heddle having a broken warp is connected.