It is known that conventional hydraulic cylinder drives work in rapid traverse with the principle of suction technology, which results in pauses when changing between rapid traverse and load travel. Alternatively, a two-stage pump is installed, which doubles the piping effort. This problem is solved by the concept of the four-chamber cylinder (Pat. No. DE200610025463), since two separate, coaxial chambers are available for rapid traverse and load operation. However, the design of the four-chamber cylinder has the disadvantage that the hydraulic forces act in a spreading manner against the built cylinder, which means that a more massive construction is required. The alternative design with one yoke each on the top and bottom of the cylinder enables the forces to be supported directly, but requires increased material and manufacturing costs. Likewise, a correspondingly long line between the two load travel oil volumes is necessary in both versions. The invention claims to transfer the load of the load forces to the load-bearing yoke through the arrangement of the chambers for load operation in the middle of the cylinder system, whereby a simpler and more compact construction of the entire cylinder becomes possible. The system thus has the advantage of lower material requirements with increased stability. In addition, the line between the two load path oil volumes is reduced to a minimum, as a result of which the response time and positioning accuracy of the cylinder system are further improved and a higher degree of efficiency is achieved. The system also has the option of locking the working piston several times against lowering by blocking all oil volumes. In addition, the new structure of the cylinder system allows the attachment of a mechanical stroke limiter and the possibility of integrating further functional elements in the lower working piston. Due to the ability of the system to be able to drive with working force on the upstroke, it is possible to integrate further tool functions into the system.
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