Industry 4.0 (I4.0) is characterized by a decentralized intelligence using service-based information technology. With the existing technologies in industrial solutions, the implementation of partly automated collaborative work of decentralized devices is difficult to achieve. Current industrial solutions fulfill manufacturer specific requirements that are not transferable to other industrial challenges. These customized solutions do not allow a plug-and-produce approach or a dynamically scalable system network. This work presents an approach for this through the use of a proposed service-based Industry 4.0 middleware. An example of its use is introduced in the form of the collaborative work of cranes, which handle the mentioned challenges. The proposed middleware is based on the service-oriented architecture with an evaluation of the I4.0 middleware using a demonstrator of collaborative work between cranes.