Today's small parts assembly lines are typically fully manual or fully automated. When human workers and robots, or other mechanical equipment, work together in a hybrid line concept, there is always a sacrifice of flexibility and a high engineering cost, caused by safety and ergonomic requirements. This paper will outline a study performed with the purpose of investigating the requirements posed on industrial robots introduced into otherwise manual assembly lines, while lifting such limitations. Moreover, it presents some results from a research effort where a robot has been developed that meets these requirements, including a discussion on how this robot could be used in future assembly systems that allow for a partial and scalable automation component.