1. Field of the Invention
The invention concerns a plastic bobbin carrier for taking up threads and yarns, with a cylindrical or conical shell which is provided with radial openings and which forms a winding surface and with one end ring at each end of the shell, whereby the shell is comprised of several shell segments configured at a distance from one another, forming a cylindrical or conical inner shell surface, said segments being joined together by supporting webs.
2. Description of the Prior Art
A known bobbin carrier of this type (DE 24 08 949 A1) incorporates intermediate rings between two end rings, whereby these intermediate rings are positioned parallel to the end rings and are axially displaced from one another, and webs parallel to the axis are located between the intermediate rings for the purpose of connecting adjacent intermediate rings. The webs are provided with bending points which facilitate bending radially to the axis, thereby enabling axial shortening of the bobbin carrier.
In the case of this known bobbin carrier, the fact that sufficient space must remain between the rings for the webs after axial compression of the bobbin carrier results in a minimum permissible limit for the spacing between the rings. Several mould segments are required in the manufacture of this known bobbin carrier, and each of these segments is individually drawn in radial direction during removal from the mould. This inevitably results in all the webs produced from such a mould segment being unmoulded in the same direction of pull and their flanks being formed accordingly. As a result, the cross-sections of adjacent webs will differ, unless an economically inviable number of mould segments is employed. This bobbin carrier therefore possesses divergent webs over its circumference which may differ, for example, with regard to their flexural strength.
Furthermore, on this known bobbin carrier the webs which engage with a ring are displaced in relation to one another in the circumferential direction. When axial compression is applied, this results in deformation of the rings concerned, which may well be undesired.
A further bobbin carrier is known (DE-PS 1 635 084) which has proved to be generally effective in the wet treatment of threads and yarns, incorporating ring elements between the end rings on the faces of the bobbin carrier, with connecting webs running primarily in the axial direction between these ring elements. In conjunction with the ring elements, the connecting webs form a winding surface on which the inner layers of a lap of thread or yarn are supported. The inner windings of such laps thus rest both on the ring elements and on the outer edges of the connecting webs which protrude into the winding surface, whereby the individual ring elements are to be regarded as rigid elements.
In the case of this known bobbin carrier, the fact that the inner windings of the lap come into direct contact with the connecting webs, which deform and alter their distances from the adjacent ring elements during compression, may result in the inner windings of the yarn becoming caught between two sections of a connecting element, or between a connecting element and an adjacent ring element. In this way, the inner windings are occasionally destroyed and cannot be unwound in the correct manner. Furthermore, a multipart mould is required in the manufacture of this known bobbin carrier, in order to ensure the required radial extension of the cross-section of the carrying elements.