Device for the detection of excessive thread tension and thread breakage

Abstract

A device for detecting the breakage of, and excessive tension in, the thread operating in knitting machinery, the device comprising a case, a first detection lever for detecting breakage of the thread, and a second detection lever for detecting excessive thread tension, both detection levers being pivotally mounted to the case. The second detection lever cooperates with a return spring attached at one end thereof to the lever and at the other end thereof to the case. The location of the points at which the spring is attached to the second detection lever and case respectively are such that the spring provides a force which resists the pivoted movement of the detection lever, such force varying by a small but uniform amount with the angle defined by the lever. The thread is applied to and supported by the second detection means. When the thread is subjected to excessive tension, the second detection lever pivots against the resisting force of the spring until it reaches an angle at which the thread escapes. The detection lever and return spring configuration is such that after the thread escapes, the return spring forces the lever back to its original position, without any need to reset it.

What is claimed is: 
     
       1. A device for detecting the breakage of, and excessive tension in, the thread operating in a knitting machine comprising: a. a case;   b. a first detection lever pivotally mounted to said case, said first detection lever being arranged and configured to detect the breakage of said thread;   c. a second detection lever pivotally mounted to said case, said second detection lever being arranged and configured to slidably support said thread; and   d. a spring means having first and second ends, said first end thereof being connected to said case at a first point and said second end thereof being connected to said second detection lever at a second point thereon, the return force of said spring tending to maintain said second detection lever against an abutment, said first and second points being situated on opposite sides of an imaginary straight line joining the axis of rotation of said second detection lever and the point at which said thread engages said second detection lever, said first point being situated nearer to the axis of rotation of said second detection lever than to said point at which said thread engages said second detection lever, and said second point being situated nearer to said point at which said thread engages said second detection lever than to the axis of rotation of said second lever the length of said spring being approximately equal to the distance between the axis of rotation of said second detection lever and said point at which said thread engages said second detection lever, whereby, said second detection lever is responsive to excessive tension in said thread by pivoting about its axis of rotation and against the return force of said spring until said thread escapes thereform.     
     
     
       2. A device for detecting the breakage of, and excessive tension in, the thread operating in a knitting machine comprising: a. a case;   b. a first detection lever pivotally mounted to said case, said first detection lever being arranged and configured to detect the breakage of said thread;   c. a second detection lever pivotally mounted to said case, said second detection lever being arranged and configured to slidably support said thread, the axis of rotation of said second detection lever being substantially co-planar with the edge of said second detection lever on which said thread is slidably supported; and   d. a spring means having first and second ends, said first end thereof being connected to said case at a first point and said second end thereof being connected to said second detection lever at a second point thereon, the return force of said spring tending to maintain said second detection lever against an abutment, said first and second points being situated on opposite sides of an imaginary straight line joining the axis of rotation of said second detection lever and the point at which said thread engages said second detection lever, said first point being situated nearer to the axis of rotation of said second detection lever than to said point at which said thread engages said second detection lever, and said second point being situated nearer to said point at which said thread engages said second detection lever than to the axis of rotation of said second detection lever, whereby, said detection lever is responsive to excessive tension in said thread by pivoting about its axis of rotation and against the return force of said spring until said thread escapes therefrom.