| 摘要 |
An apparatus for displacing material includes a transport thread having a central thread spiral and an outer thread spiral. The outer thread spiral is fixed in conjunction to one of the radially directed defining surfaces of the central thread spiral The central thread spiral is dimensioned so as, without permanent deformation, to absorb at least the major portion of the mechanical forces occurring in the axial and radial direction of the transport thread. The outer thread spiral has an outer surface which faces away from the geometric centre axis of the transport thread and is of shorter extent in the axial direction of the transport thread and is located more distally from the centre axis than the outer surface of the central thread spiral. By regulating the extent in the axial direction of the transport thread of the surface of the outer thread spiral turned to face the substrate, the abutment pressure of the transport thread will be adapted to the substrate in relation to the properties of the material being displaced.
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