drive member at the position 50 from one of the cooperating surfaces of the rim to the other extending from the motor 42 is a cord 52 leading to a foot operated speed control 54 having a pedal 56 the control 56 is connected by a cord 58 to a source of electrical current the control 54 is of a conventional form by which current does not reach the motor 42 unless the foot is depressed upon the pedal 56 the current is increased or decreased as desired by increasing or decreasing the pressure upon the pedal the motor 42 has a variable speed which increases with the amount of current which it receives preferably the motor 42 and control 54 are of the types commonly used as motors and foot controls for electrically operated domestic sewing machines fig3 shows a second embodiment in the form of a foot controlled aid for unwinding yarns during manual knitting a driven member 60 comprises a flat circular disc similar to the member 12 of fig1 and 2 except that it does not have the cut out 26 or projections similar to the projections 32 and 34 of fig1 and 2 the motor 42 and drive member 46 are the same as shown in fig1 and 2 mounted on the member 60 are cylindrical cans 62 and 64 each secured to the member 60 in offset relation.