Screw Clamping Structure for Easy Release After Welding

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Solution Overview

Problem

Traditional screw clamping devices for welding elements face difficulties in releasing the workpiece due to thermal expansion and increased friction, requiring excessive manual effort and potentially causing safety issues or component deformation.

Innovation Solution

A screw clamping device with an axially movable clamping member and a thrust member with a thin pitch threaded portion, allowing for easy release by leveraging thermal expansion reactions and minimizing friction, featuring a clamping member that slides between clamping and release positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a screw with thick pitch is used to leave clearance between the screw and welding element, then the welding element can accommodate thermal expansion, but the clearance causes jamming between the screw and welding element during welding

Engineering Contradiction:
Improveaccommodation of thermal expansionVSAvoidjamming between screw and welding element
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The clamping device is divided into two independent threaded components: a first threaded portion on the rod for clamping, and a second threaded portion on a separate thrust member for release. This segmentation allows each threaded portion to have different pitch characteristics - the first with thick pitch for thermal expansion accommodation and the second with thin pitch for precise control and easy release, thereby resolving the jamming problem while maintaining adaptability.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If manual extraction force is applied to remove the welded element, then the element can be extracted from the clamping device, but excessive effort is required and safety issues or plastic deformations may occur

Engineering Contradiction:
Improveextraction of welded elementVSAvoidexcessive operator effort and potential safety issues
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The thrust member is designed to leverage the thermal expansion reactions that occur during welding. After welding, the workpiece's thermal expansion naturally pushes against the thrust member, which then automatically pushes the clamping member away from the workpiece through the thin pitch threaded portion. This self-service mechanism eliminates the need for excessive manual extraction force, allowing easy release without safety issues or deformations.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If a traditional clamping structure is used to hold the welding element, then the element can be clamped in position, but significant friction increases between the clamping plate and welding element

Engineering Contradiction:
Improveclamping of welding elementVSAvoidfriction between plate and welding element
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The clamping member is designed to be axially movable along the rod's axis, transitioning between a clamping position (for stable welding) and a release position (for easy extraction). The thrust member enables dynamic adjustment of the clamping force by leveraging thermal expansion reactions. This dynamic design allows the system to maintain stable clamping during welding while reducing friction during release, resolving the contradiction between stability and friction.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Facilitates safe and effortless release of the workpiece by reducing friction and jamming, allowing for easier extraction and reducing operator effort, while maintaining structural integrity and longevity.

Implementation Method 1

the tensions that develop caused by the normal thermal expansion occurring during welding

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the aforementioned tensions generally produce a significant increase in friction between the plate and the welding element

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3944924B1Screw clamping device
Publication Date: 2024.07.17 HITACHI RAIL STS SPA
  • EP3944924B1 patent drawingFigure 1~2
  • EP3944924B1 patent drawingFigure 3~4
  • EP3944924B1 patent drawingFigure 5

AI summary

A screw clamping device (4) includes a first rod (9) with a first threaded portion (14) to be screwed into a stop member (3) adapted to support a workpiece (2), and a clamping member (17) coupled with the first rod (9) and arranged around the first rod (9), wherein the clamping member (17) has a clamping surface (18) transverse to the first rod (9), which comes into contact with the workpiece (2), such that the latter is clamped between the stop member (3) and the clamping surface (18), wherein the first rod (9) has a second threaded portion (41) so that the clamping member (17) is axially sliding with respect to the first rod (9) between the first and the second threaded portions (14, 41), the device further comprising a threaded thrust member (40) and that can be screwed into the second threaded portion (41) to axially push the clamping member (17) towards the first threaded portion (14).