Abstract: A lock assembly includes a handle assembly including a tubular member having an axial hole defined in a first end thereof and extending along a longitudinal axis thereof and a receptacle defined in a second end thereof and in communication with the axial hole, and a handle formed on the second end of the tubular member. A lock core assembly is removably mounted to the receptacle of the handle assembly and includes a lock core therein. The lock core includes a key hole defined in a first end thereof. A transmission device is received in the axial hole of the tubular member and includes a first end and a second end. The second end of the transmission device includes an end face plate extending in a direction transverse to a longitudinal axis of the key driving means, and two spaced positioning rods project outwardly from the end face plate and extend away from the first end along a direction parallel to the longitudinal axis of the transmission device.