Fluid operated web break detector assembly with peripheral flange for microswitch operator

Claim 1

For use in apparatus which is to be mounted in proximity to a moving web for detecting and reacting to breaks and voids in the web and which includes as one part thereof a source of pressurized fluid to be directed against one side of the web and as a further part thereof control means for governing the starting and stopping of movement of the web, the improvement which consists in A. a structure to be positioned in facing relation to, but on the opposite side of the web from, the pressurized fluid source, said structure comprising 1. a deflectable part operable when deflected to actuate a controlling element of the said control means for stopping movement of the web, 2. a housing at least partially enclosing the deflectable part and having an opening directed toward the normal path of the web surface in facing proximity to the said pressurized fluid source, and 3. a member mounted on said deflectable part and movable when subjected to surface pressure to deflect the deflectable part, said member a. extending through and generally conforming to said opening, b. having a surface perpendicularly opposed to the normal flow of fluid from said pressurized fluid source, and also c. having a lip extending peripherally from said member in a region between the outer peripheral portion of the opening and the normal path of the web, whereby the lip, upon movement of the member away from the pressurized fluid source under the influence of pressurized fluid from that source, acts i. to cover the peripheral portion of the opening, and ii. to prevent movement of the member through the opening.