| 摘要 |
The invention relates to a novel screw tensioning device with a screw tensioning cylinder with a high-pressure hydraulic pump for pretensioning screws and loosening extremely secure pretensable screw connections and an accompanying control method. The problem is to create a screw tensioning device that can generate high tensioning forces, that requires less energy, that can be used for all usage locations without problems, that can be easily controlled and that makes precisely controlled pretensioning possible. A high-pressure hydraulic pump 39 is integrated into the interior of the screw tensioning cylinder 38 in accordance with the invention. This high-pressure pump 39 is connected to a sealed hydraulic accumulator 42. A drive unit 40 that can be pneumatically actuated is arranged on or in the screw tensioning cylinder 38. The drive unit 40 can be designed on the constructional basis of a diaphragm cylinder 42 or on the basis of a piston cylinder. The pneumatic drive unit 40 is connected to a compressed air feed device to actuate it. The pretensioning force is brought about through the high-pressure pump 39 by means of an oscillating high-pressure piston that moves the working piston 15. The difference is that the high required hydraulic pressure of up to 1000 bar and beyond, if necessary, is not provided via an additional, expensive, separate high-pressure system, but is instead created in a specially designed screw tensioning cylinder 38 itself. Other pressure-control valves are arranged in such a way that the novel, single-action control method for the screw tensioning device makes universal use in any desired usage locations possible. |
