Pen Clamping Mechanism Radial Spring Axis Alignment

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Solution Overview

Problem

Existing pens with clamping mechanisms for secure attachment to clothing suffer from functional reliability issues due to transverse forces generated during pivoting, which can lead to mechanical failure and inadequate clamping of objects.

Innovation Solution

A pen design featuring a torsion spring with a geometric axis aligned with the pivot axis, where a radially acting tension force induces a bending moment, eliminating the need for transverse forces and enhancing stability, with a compact and aesthetically improved construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a helical spring with geometric axis orthogonal to the pen axis is used, then the pen can be attached to clothing pockets, but transverse forces are generated during pivoting that can deteriorate the connecting mechanism and cause mechanical failure

Engineering Contradiction:
Improvefunctional reliabilityVSAvoidtransverse forces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the geometric parameter of the spring axis orientation from orthogonal to parallel with the pen axis. This parameter change transforms the force transmission mode, eliminating transverse forces during pivoting and converting them into axial forces that the spring can handle more effectively, thereby improving reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a lever as an intermediary element between the clip and the spring. The lever acts as a force transmission mediator that converts the pivoting motion into a motion that applies force radially to the spring along its geometric axis, preventing direct transmission of harmful transverse forces to the spring connection

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the geometric axis of the restoring device is orthogonal to the pen axis, then the restoring force acts axially, but angular moment generates force-components that do not contribute to effective tensioning

Engineering Contradiction:
Improveeffective tensioningVSAvoidineffective force components
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the spatial parameter of the spring axis from orthogonal to parallel with the pen axis. This reorientation ensures that the restoring force acts in the same direction as the required tensioning force, maximizing the effectiveness of energy transmission and eliminating wasted force components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs asymmetric positioning of the spring axis relative to the pen body, aligning it with the pen axis rather than orthogonal to it. This asymmetric configuration optimizes the force transmission path, ensuring that the restoring device's geometric axis coincides with the direction of the required restoring force for maximum efficiency

Inventive Principle:
Principle #4Asymmetry

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

The design provides a reliable and secure clamping mechanism that maintains object retention without mechanical failure, allowing for easy mounting and increased stability, while maintaining a compact and aesthetically pleasing form.

Implementation Method 1

an elastic restoring device coupled to both parts and defining a geometric axis, the restoring force of the restoring device counteracting a pivoting movement of both parts which opens the clamping area

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the restoring device is always meant to be a torsion spring

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP2621735B9Pen with clamping area
Publication Date: 2021.03.17 STABILO INTERNATIONAL GMBH
  • EP2621735B9 patent drawingFigure 1
  • EP2621735B9 patent drawingFigure 2
  • EP2621735B9 patent drawingFigure 3a

AI summary

The invention is related to a pen, having a first part, a second part pivotable with respect to the first part, wherein an area for clamping an object placed therein, is formed between said both parts, and an elastic restoring device coupled to both parts and defining a geometric axis, the restoring force of the restoring device counteracting a pivoting movement of both parts which opens the clamping area, wherein the restoring force acts in a radial direction with respect to the geometric axis.