| 摘要 |
809,081. Removing tubes from mandrels. ETERNIT S. P. A. April 10, 1956 [June 17, 1955], No. 10889/56. Class 99(2). In the manufacture of fibro-cement tubes, a tube is removed from a mandrel by introducing compressed air between the outer periphery of the mandrel and the inner wall of the tube, and at a number of points along a generatrix of the mandrel to provide a coherent flow of air in the axial direction of the mandrel, the air then being distributed over the surface of the mandrel by at least one rotation of the tube and mandrel during a calendering operation on the tube. The latter operation may be carried out in the tube-making machine, or the tube and mandrel may be transported to a further calender to effect removal of the tube from the mandrel. As shown in Fig. 1, the mandrel 1 comprises a thin-walled, iron tube provided with holes 2, and filled with wood 3 having a passage 4 coincident with the holes. Connected to the passage at one end thereof and by a rotaty joint 9 is an air-supply pipe 7 having a control valve 8. In modifications, (a) a flanged diaphragm 13, Fig. 3, incorporating a channel 4 is fixed inside the mandrel, and (b) the passage 4 is formed in an internal rib of the mandrel, there being an oppositely disposed balancing rib. |
