Cardan shaft with a closable maintenance orifice in protective tubes

摘要

The invention relates to a cardan shaft for the drive of agricultural machines. In addition to the two profiled tubes 1 displaceable one in the other and serving for the transmission of torque, there are provided two protective tubes 5, 6 which are correspondingly axially displaceable one in the other. So that the profiled tubes can be lubricated, there is provided a maintentance orifice which, in the case of a specific cardan-shaft length, is obtained by means of the coincidental positions of two orifices 11, 12 in the protective tubes 5, 6. However, in the state of non-use, the orifice 11 in the outer protective tube 6 is covered by a closing sleeve 9. When the cardan shaft is extended, after the displacement of the closing sleeve 9 for the purpose of access to the orifices, the closing sleeve 9 is automatically transferred into the closing position again by means of a cam 13. This ensures improved safety, since it is guaranteed that the orifices are always closed when the cardan shaft is in use. <IMAGE>