Abstract: A drive train is provided comprising: a motor assembly, a gear box assembly (40) and an encoder assembly. The motor assembly comprises an electric motor (21) and a rotatable shaft (26) defining an input axis (27), the shaft (26) comprising a first set of gear teeth (28). The gear box assembly (40) comprises an annular gear (48, 50) comprising a second set of gear teeth (48, 50) which intermesh with the first set of gear teeth (28), and a housing (42, 44, 45) which comprises a fixed portion (42) to which the motor assembly is mounted and a rotatable portion (45) fixed to the annular gear (48, 50) and providing the output from the drive train about an output axis (72) offset from the input axis (27). The encoder assembly is arranged and configured to measure the rotation at the output axis (72). A central opening is defined through the gearbox assembly (40) in alignment with the output axis (72) and passing through the housing (42, 44, 45) and the annular gear (48, 50).

Abstract: A drive train is provided comprising: a motor assembly, a gear box assembly (40) and an encoder assembly. The motor assembly comprises an electric motor (21) and a rotatable shaft (26) defining an input axis (27), the shaft (26) comprising a first set of gear teeth (28). The gear box assembly (40) comprises an annular gear (48, 50) comprising a second set of gear teeth (48, 50) which intermesh with the first set of gear teeth (28), and a housing (42, 44, 45) which comprises a fixed portion (42) to which the motor assembly is mounted and a rotatable portion (45) fixed to the annular gear (48, 50) and providing the output from the drive train about an output axis (72) offset from the input axis (27). The encoder assembly is arranged and configured to measure the rotation at the output axis (72). A central opening is defined through the gearbox assembly (40) in alignment with the output axis (72) and passing through the housing (42, 44, 45) and the annular gear (48, 50).