Rotatable drum assembly

A drum assembly comprising a rotatable drum and a gear rim mounted on the outside of said drum and radially spaced therefrom by means of a flexible connection;

• wherein:
• (a) said gear rim has bevel toothing;
• (b) said flexible connection is a frustoconical casing, a narrower end of which has a diameter substantially corresponding to the outer diameter of said drum and is secured to the outside thereof, and a wider end of which has a diameter substantially corresponding to the diameter of the gear rim and is secured to the one side of said rim, said casing extending from its connection to said gear rim in a direction such that said casing receives a compressive loading due to said bevel toothing of said gear rim cooperating, in use, with a complementary driving gear;
• and,
• (c) said gear rim is provided on the other side thereof with a stiffening ring having substantially the same radial stiffness as that of said casing, and being spaced from said drum, such that said stiffening ring causes the axis of said gear rim to maintain substantial parallelism with the axis of said rotatable drum under normally encountered axial and radial loads.