Auxiliary drive apparatus

Abstract

Auxiliary drive apparatus including a wheel having an axis of rotation, and first and second wheel engagement elements arranged for driving engagement with the wheel, at least one of the wheel engagement elements being coupled to a motor, for being driven thereby, the first and second of wheel engagement elements being arranged for rotation about respective first and second engagement element rotation axes, the first and second wheel engagement elements being mounted such that the effective traction of the engagement thereof with the wheel increases automatically with increased resistance to rotation of the wheel and decreases automatically with decreased resistance to rotation of the wheel, and wherein a mounting of the first and second wheel engagement elements is such that a separation between the first and second wheel engagement element rotation axes, the separation lying parallel to the axis of rotation of the wheel, is variable.

Dependencies are inferred from the claim text.