A comminution device can include a crushing body extraction mechanism. The crushing body extraction mechanism can be configured to permit one or more crushing bodies (e.g. rollers of a roller press, etc.) to be continuously moved linearly away from a frame to expose the crushing bodies from the frame. In some embodiments, the extraction mechanism may be configured to utilize one or more rack and pinion mechanisms. The pinion for each such mechanism may be powered by one or more rotary motors or other type of rotary drive mechanism. In other embodiments, the extraction mechanism can include one or more rack and ratchet mechanisms. Each rack and ratchet mechanism may include a hydraulic cylinder or other linear actuator that is extendable and retractable for actuating motion of a ratchet along a rack having columns of differently angled steps to facilitate extension and retraction of one or more crushing bodies.