US Patent 7834865 Rotary actuator

A rotary actuator includes a shaft with a knob which are rotatable about a shaft axis. The actuator includes a haptic effect device connected to the knob via the shaft. The haptic device is rotatable about the axis and includes a detent ring and a bolt fixed to the shaft. The haptic device and gearing engage one another such that haptic device is fixed in place unless the gearing is driven and the haptic device rotates when the gearing is driven. The bolt engages the detent ring to act as a mechanical catch for producing a haptic effect when the haptic device is fixed in place and the knob is manually rotated. The bolt engages the detent ring such that the haptic device together with the knob rotate when the gearing is being driven by a motor whereby the knob is rotated without manual intervention.