Abstract: In a plastic tube for yarn bobbins having a substantially cylindrical body one end is broader than the other so that two tubes can be axially inserted into each other. The broad end is provided with perforations for through flow of dye liquid whereas the narrow end is without perforations. The tube is provided with longitudinal ribs to carry the yarn. These ribs connect the two ends of the tube. Thereby an annular opening is established which is bridged only by the ribs. Dye liquid can from this opening enter the passages on the narrow end bounded by the ribs and the yarn.

Abstract: A tube of plastic for yarn bobbins of the conical type which has one or more V-shaped slits substantially along generatrices of the cone surface and extending at least over the major part of the tube length, the pointed end of the slit being in the broad end of the tube and the open end of the slit being in the narrow end of the tube.

Abstract: A tube for yarn bobbins of a moulded plastic material which may be axially compressed, said tube being composed of a number of connected concentric rings (2), where the two end rings (1 and 3) are differently shaped with inner and outer cylindrical surfaces (4 and 6) or conical surfaces adapted to each other, said surfaces providing a seal, and where the cylindrical or conical surface is formed by arms (9) extending from the rings along generatrixes, and the rings are connected with strings (11) shaped as springs which when stretched extend substantially parallel to the generatrixes but which are located under the cylindrical or conical surface formed by the arms.