| 摘要 |
The casings have (1,2) a mainly circular cross section and are rotatable and axially displaceable relatively to one another. The outer casing (1) is provided with at least one radially inwardly projecting extension (6) at its open end .The inner casing is provided with partly an axial channel (9) in which the extension can run without hindrance, and partly an axially running row of outwardly directed projections (11) between which the extension (6) is insertable to lock the two casings together axially. Between the channel and the projection row is an axial ridge (10) over which the extension has to pass under elastic material deformation in order to be able to be pushed from the channel to the projection row or vice versa. |
