Patent ID: 7394219

Claim:
An encoder unit for a motor having a shaft and a flange end, comprising: (a) a printed circuit board having an underside; (b) an encoder housing fixed to the electric motor and comprising a base plate, a cover arranged parallel to the base plate, and side walls, wherein the base plate is releasably fixed at the flange end of the motor and includes a recess sized to receive the motor shaft, wherein the encoder housing includes guiding grooves sized to receive the printed circuit board in parallel to the base plate, and wherein at least one of the side walls is removably anchorable to the encoder housing; (c) a timing disc hub disposed within the recess of the encoder housing base plate and beneath the underside of the printed circuit board; (d) a timing disc supported on the timing disc hub and having code markings; (e) at least one sensor connected to the printed circuit board and disposed in the region of the code markings, the sensor being fixed in all three coordinate directions; and (f) an abutment supported by the printed circuit board and having a first position in contact with the timing disc hub when the printed circuit board is not fully received within the encoder housing and a second position clear of contact with the timing disc hub.