A thin film transistor is provided with a precisely, lightly doped drain structure formed on a substrate of insulators, such as a glass sheet. The device of the invention comprises a support means for supporting a wheel resting thereon, and transfer means for raising and lowering the support means to move it from a first position, in which the means is disposed close to the floor surface in order to receiveunload the wheel, to an upwardly raised position in which the wheel rests on said upper member, and vice versa. To guarantee that temperature fluctuations do not adversely affect the current transfer, the slip elements are configured as disc elements that consist of or contain carbon material.