Method for tensioning screw bolts, as well as screw bolt and screw bolt tensioning device for carrying out the method
OwnerFrank Hohmann, Jörg Hohmanninventors
Life of this patent
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Abstract
This invention relates to a method for hydraulically tensioning screw bolts as well as to screw bolts and screw bolt tensioning devices for carrying out the method. It is proposed to apply the total pretensioning force for one part via an external thread and for the remaining part via an internal thread of the bolt end.
Claims15
A screw bolt which can be passed through throughbores in machine parts to be clamped together and comprises a bolt head, which is provided for being supported on one side of the machine parts, and a bolt end, which is provided for being screwed to a screw bolt tensioning device and includes an external thread and at least one internal thread extending from the end face along the bolt axis,
- wherein the outer diameter of the bolt end is greater than the diameter of the throughbores.
A hydraulic screw bolt tensioning device for tensioning a screw bolt which can be passed through throughbores in machine parts to be clamped together and comprises a bolt head, which is provided for being supported on one side of the machine parts, and a bolt end, which is provided for being screwed to a screw bolt tensioning device and includes an external thread and at least one internal thread extending from the end face along the bolt axis, comprising:
- a cylinder with a cylinder axis, which on a first end face includes a supporting surface for supporting on the machine parts,
- an outer exchange bushing arranged in the cylinder so as to be axially displaceable relative to the same and includes a first portion with an internal thread for screwing onto the external thread of a bolt end and a second portion with an axial through bore which opens into the first portion,
- an inner exchange bushing passing through the cylinder and the through bore of the outer exchange bushing and being rotatable and axially displaceable relative to the same and at a first end includes an external thread which is screwed to the internal thread of the bolt end,
- a first piston firmly connected with the outer exchange bushing and being axially displaceable in the cylinder by a pressure medium in the direction facing away from the supporting surface, wherein the cylinder includes a first pressure medium supply,
- a second piston firmly connected with the inner exchange bushing and being axially displaceable in the cylinder by a pressure medium in the direction facing away from the supporting surface, wherein the cylinder includes a second pressure medium supply,
- wherein the size ratio of the active piston areas of the first and second pistons relative to each other corresponds to the size ratio between the portions of the total pretensioning force to be transmitted by the outer and inner exchange bushings, and
- a pressure medium port in fluid connection with the first and with the second pressure medium supply.
Dependencies are inferred from the claim text.