Patent ID: 6955622

Claim:
A preassembled drive unit ( 1 ), comprising a support body ( 2 ), at least one drive wheel ( 3 , 8 ), at least one removable mounting aid ( 9 ) and an endless drive ( 4 ); the support body ( 2 ) having at least one wheel receiver ( 6 , 10 ) and at least one further wheel receiver ( 10 , 28 , 29 ); each of the at least one drive wheels ( 3 , 8 ) is received in a respective wheel receiver ( 6 , 10 ); each of the at least one removable mounting aid ( 9 ) is received in a respective further wheel receiver ( 6 , 10 , 28 , 29 ); and the endless drive ( 4 ) is wound around the at least one drive wheel ( 3 , 8 ) and the at least one removable mounting aid ( 9 ), securing the at least one drive wheel ( 3 , 8 ) in position, the removable mounting aid ( 9 ) retaining the endless drive ( 4 ) so as to accommodate a further drive wheel ( 8 , 19 , 20 ) in the further wheel receiver, said further drive wheel ( 8 , 19 , 20 ) being engaged by the endless drive upon removal of the removable mounting aid ( 9 ).