Thread changer including displacer arm for defined tread movement, holds thread length constant from tip of changer triangle to roller contact point, also keeping thread tension constant

摘要

Geometric relationships of the design satisfy the condition that thread length from the tip of the changer triangle to the contact point of thread on the curvilinear roller remains constant, hence maintaining thread tension constant. Preferred features: The changer arm is a pointer arm with set radius and predetermined pivot point. The curvilinear section has predetermined radius and center. The fixed relationship between the combination changer arm and curvilinear section, relates to the position of the pivot relative to the position of the center. The relationship between the combination of the changing arm/curvilinear section and the roller refers to a spacing between roller and linear section. Spacing of the linear section center to the rotation axis of the roller implies in addition the relationship between changer triangle tip and combined changer arm/curvilinear section. Further detailed description of the relationships is provided, and variants are described, based on the foregoing principles.