Screwing Device Re-indexing Prevents Nut Loosening

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing screwing device techniques for tube connection nuts face challenges in reliable re-indexing, which can lead to partial unscrewing and quality degradation, especially in critical applications like brake systems, due to the risk of loosening during re-indexing operations.

Innovation Solution

The method involves a screwing device with a motor and transmission system that rotates the terminal member in the screwing direction during re-indexing to ensure precise positioning and prevent loosening, using a predetermined angle and torque measurement to guarantee the open position, thereby eliminating the risk of unscrewing and maintaining the quality of tightening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the terminal member is rotated in the unscrewing direction during re-indexing to return to the open position, then the re-indexing operation can be performed, but the nut may loosen and the tightening quality degrades

Engineering Contradiction:
Improvere-indexing operationVSAvoidtightening quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies the inversion principle by rotating the terminal member in the screwing direction (clockwise) during re-indexing instead of the conventional unscrewing direction. This counterintuitive approach ensures that if the nut remains engaged on the tube, the rotation will tighten it further rather than loosen it, thereby preventing quality degradation while still achieving the open position for device removal

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent implements preliminary anti-action by applying a tightening moment during re-indexing to counteract any potential loosening. The control unit rotates the terminal member in the screwing direction, creating a preliminary tightening effect that prevents the nut from loosening during the re-indexing operation, thus maintaining tightening quality

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If the terminal member is rotated in the screwing direction during re-indexing to prevent loosening, then the tightening quality is maintained, but the risk of over-tightening increases if the nut is not removed

Engineering Contradiction:
Improvetightening qualityVSAvoidover-tightening risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies feedback by implementing a verification phase where the control unit monitors torque or rotation parameters during re-indexing. If the nut is detected to remain engaged (through torque sensing or rotation resistance detection), the control unit stops the rotation early, preventing over-tightening. This feedback mechanism allows the system to adapt the re-indexing operation based on the actual state of the nut

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses partial action by limiting the rotation angle during re-indexing to just enough to achieve the open position, not a full 360 degrees. The control unit precisely controls the rotation to stop when the open position is reached or when the nut is detected to be engaged, applying only the necessary tightening moment without excessive rotation that would cause over-tightening

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If a conventional cylindrical screw socket is used, then the tool structure is simple, but it cannot accommodate the tube passing through the nut

Engineering Contradiction:
Improvetool structureVSAvoidtube accommodation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies segmentation by dividing the tool into distinct functional components: the casing with its lateral opening, the terminal member with its own lateral opening and hole, and the tube passage path. This segmentation allows each component to perform its specific function - the casing provides structural support and one opening, the terminal member provides the gripping interface and second opening, together enabling tube passage while maintaining a relatively simple overall structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements nesting by placing the terminal member inside the casing, with the terminal member's lateral opening and hole nested within the casing's lateral opening structure. This nested arrangement allows the tube to pass through both openings sequentially, accommodating the tube while keeping the tool structure compact and integrated rather than requiring separate components

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3505301B1Method for screwing a nut around a tube comprising re-indexing, and corresponding device
Publication Date: 2024.03.06 ETABLISSEMENT GEORGES RENAULT SAS
  • EP3505301B1 patent drawingFigure 1~2
  • EP3505301B1 patent drawingFigure 3~5
  • EP3505301B1 patent drawingFigure 6a~6b

AI summary

Method of screwing a tube connecting nut to an element by means of a screwing device, said tube extending through said nut, said device comprising a housing (16), a rotating end member (10) adapted to cooperate with said nut, a motor (17) and a transmission adapted to drive said end member (10) and having an operating clearance, said housing (16) and said end member (10) each having a lateral opening allowing, when they coincide, the passage of said tube into the end member (10), and thus defining an open position of the end member (10), said method comprising at least one screwing cycle comprising at least the following successive steps: - a step (61) of positioning around the tube the device in the open position, by passing the tube through the lateral openings of the housing and the end member (10);- a step (62) of engaging the end member (10) with the nut; - a step (63) of tightening (3) the nut; - a step (64) of disengaging the end member (10) from the nut; - a step (66) of removing the device from the tube; Said method comprising, between the step of disengaging the end member from the nut and the step of removing the device from the tube, a re-indexing step during which said motor returns the end member to said open position by rotating it in the direction of tightening.