Abstract: An exercise treadmill having a direct drive AC induction motor controlled by an AC motor driver/controller. The driver/controller is itself controlled through programmable circuitry having a display and keyboard with user input options. The controller receives signals from a speed sensing device attached to the AC induction motor to maintain the rotational speed of the AC motor within preselected limits. The AC induction motor is attached to one or more flywheels and directly engages, through a drive roller, a walking belt. The matched combination of an AC motor driver/controller with appropriately sized flywheels allows utilization of a variable speed AC induction motor for the direct drive of the treadmill belt.

Abstract: A treadmill which includes a generally rectangular frame defining a walking plane, said frame having laterally disposed parallel trending side rails (18); a drive roller, said drive roller having walls defining a hollow cylinder; a free roller (10), said free roller (10) having walls defining a hollow cylinder, the walls of said drive and said free rollers (10) each having an annular groove (38) in the outer walls (36) thereof, the groove (38) located closer to an end of said rollers (10) than the longitudinal center line of said frame; shaft (12) for mounting said rollers (10) between said rails (18) and in generally perpendicular relation; an endless belt (20) of flexible material having an outer walking surface and an inner surface, the inner surface having an inwardly projecting alignment ridge (44) mating with said grooves (38) of said rollers (10) to allow a substantially flush fit of said rollers (10) against said belt (20) and to prevent said endless belt (20) from wandering on said rollers (10).

Abstract: A treadmill which includes a generally rectangular frame defining a walking plane, said frame having laterally disposed parallel trending side rails (18); a drive roller, said drive roller having walls defining a hollow cylinder; a free roller (10), said free roller (10) having walls defining a hollow cylinder, the walls of said drive and said free rollers (10) each having an annular groove (38) in the outer walls (36) thereof, the groove (38) located closer to an end of said rollers (10) than the longitudinal center line of said frame; shaft (12) for mounting said rollers (10) between said rails (18) and in generally perpendicular relation; an endless belt (20) of flexible material having an outer walking surface and an inner surface, the inner surface having an inwardly projecting alignment ridge (44) mating with said grooves (38) of said rollers (10) to allow a substantially flush fit of said rollers (10) against said belt (20) and to prevent said endless belt (20) from wandering on said rollers (10).