Hydraulic Tightening Tool Torque Limiter Spring

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Solution Overview

Problem

Hydraulic wrenches used for tightening and loosening large threaded elements face risks of mechanical failure and wear due to high actuation forces, particularly during loosening operations, where instantaneous energy release can cause damage to the tool and threaded components.

Innovation Solution

A hydraulically operated tightening tool with a piston head featuring parallel tabs and an elastically variable articulation spring that prevents force transmission beyond a pre-fixed value by allowing the spring to exit grooves when excessive force is applied, thereby ceasing force transmission and preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If high actuation forces are applied to loosen threaded elements, then loosening capability is improved, but mechanical failure and wear of tool components occurs

Engineering Contradiction:

Improveactuation forceVSAvoidmechanical failure risk

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent implements a torque limiter device with a spring element and cam surface that activates before excessive force can damage the tool. The spring compresses and the cam surface deflects the actuating ring when torque exceeds the predetermined limit, cushioning the blow and preventing mechanical failure of critical components like the piston and threaded elements.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If torque limiter devices are added to prevent mechanical failure, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improvebreak preventionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The torque limiter device is merged with the existing hydraulic cylinder and actuating ring assembly. The spring element, cam surface, and reaction base are integrated into the tool's structural framework, allowing the torque limiting function to be achieved without adding separate, independent components. The actuating ring serves dual purposes: transmitting torque and activating the torque limiter through deflection along the cam surface.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If fuse elements are used to prevent excessive force damage, then reliability is improved, but ease of operation deteriorates due to required disassembly and replacement

Engineering Contradiction:

Improveforce limitationVSAvoidmaintenance complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The torque limiter device is designed to be self-resetting. After the spring compresses and the cam surface deflects the actuating ring to limit torque, the components automatically return to their original positions when the excessive force is removed. This eliminates the need for manual intervention, disassembly, or replacement of fuse elements, maintaining ease of operation while providing continuous protection.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9533402B2Hydraulically operated tightening tool

Publication Date: 2017.01.03 ASOCIACION DE INVESTIGACION METALERGICA DEL NOROESTE AIMEN

AI summary

The present invention relates to a hydraulically operated tightening tool comprising a body (1) in which there is assembled a hydraulic cylinder and an actuating ring (6) articulated to the body (1) which receives the action of the piston (3) of the hydraulic cylinder. Two axial tabs protrude from the head of the piston (3) between which tabs there is articulated the actuating ring (6) by means of a shaft with an elastically variable length protruding partially on both sides of the ring. The tabs (7) have transverse facing grooves (16) in which there are housed the ends of the mentioned shaft.