Hydraulic tensioning and release tool for expansion fasteners

Abstract

A hydraulic tensioning and release tool for an expansion fastener of a type having an elongate member with a tapered portion for fastening a workpiece, said tool comprising: a sleeve for placement about the tapered portion; one or more cylinders including at least one cylinder for generating compressive force against the workpiece; a release piston for displacing the sleeve and a tension piston for coupling to an end of the elongate member, the tension piston and at least one of the one or more cylinders defining at least one tension chamber and the release piston and at least one of the one or more cylinders defining at least one release chamber; hydraulic ports in fluid communication with said tension chamber and said release chamber for application of hydraulic pressure thereto to displace the tension piston and the release piston for respectively tensioning the elongate member and for releasing the sleeve from the tapered portion; and a tension retaining arrangement for retaining the end of the elongate member in tension subsequent to removal of hydraulic pressure from the tensioning chamber.

Description

technical field [0001] The present disclosure generally relates to expansion bolts and devices for tensioning and releasing expansion bolts. [0002] related application [0003] This application claims priority to Australian Provisional Patent Application No. 2018903896, filed 15 October 2018, the entire disclosure of which is incorporated into this application by reference. Background technique [0004] Any reference to methods, apparatus or documents of the prior art should not be taken as constituting any evidence or admission that they form, or form part of the common general knowledge. [0005] In many cases, flange couplings are commonly used to interconnect rotatable shafts in order to transmit torque from one shaft to another. Flange connectors are often used to transmit large torques and require the manufacture of expensive close or interference fit bolted elements, and place high demands on the tolerances and surface finish of the holes through the flanges. Eve...

AI Technical Summary

Problems solved by technology

[0011] A problem with expansion bolts has been found to be that they are difficult to remove when required, for example when it is necessary to separate two flanges from each other

The reason for this difficulty is that the radial force exerted by the split sleeve 5 on the inner wall of the hole of the flange can cause an interference fit between the sleeve 5, the stud 3 and the holes of the flanges 33, 35, This interference fit can only be overcome using specialized techniques such as using gas cutting or applying high pressure oil in an attempt to "float" the bolted assembly

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