Retractable Mechanism Cam Locking for Accidental Unlock Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing retractable mechanisms in briefcases and electronic devices lack reliability, robustness, and precision, often leading to accidental unlocking and requiring excessive stroke for operation, while also limiting integration into various applications.

Innovation Solution

A retractable mechanism featuring a cam path with a locking portion and a cam follower integral with a rocker, combined with a retaining member that prevents accidental unlocking by exerting a magnetic attraction force, allowing a minimal stroke for unlocking and integration of functional elements like connectors or sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional retractable mechanism is used, then the mechanism can be actuated by two successive pressures, but the unlocking stroke is excessive and accidental unlocking occurs

Engineering Contradiction:
Improvereliability of actuationVSAvoidunlocking stroke
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent changes the geometric parameters of the cam track, specifically introducing a locking portion with a specific shape that engages the cam follower. This modifies the motion parameters to achieve precise control over the unlocking stroke, reducing it from excessive to minimal while preventing accidental unlocking through the designed engagement geometry.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The retaining member acts as an intermediary element between the cam follower and the rocker. It mediates the interaction by preventing the cam follower from disengaging from the locking portion unless a sufficient force is applied, thereby controlling the unlocking process and preventing accidental activation while maintaining reliable actuation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the retractable box is locked securely in the frame, then reliability is improved, but the mechanism becomes difficult to unlock

Engineering Contradiction:
Improvelocking reliabilityVSAvoidunlocking ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The cam track is designed with a locking portion that provides secure engagement during normal operation, changing the mechanical parameters to ensure reliable locking. However, the same geometry is configured to release easily when the appropriate actuating force is applied, balancing security with ease of operation through precise geometric design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The retaining member provides dynamic control over the locking mechanism. It maintains the locked state during normal use but allows easy unlocking when the actuator applies sufficient force to overcome the retaining member's constraint, enabling the system to transition smoothly between locked and unlocked states.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a retaining member is added to prevent accidental unlocking, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveprevention of accidental unlockingVSAvoidcomplexity of actuator
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retaining member is a simple intermediary element that adds minimal complexity while providing significant reliability improvement. It acts as a straightforward constraint that prevents accidental unlocking without requiring complex control systems, motors, or sensors, thereby maintaining device simplicity while enhancing security.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of using complex electronic or hydraulic systems to prevent accidental unlocking, the patent employs a simple mechanical retaining member that leverages basic mechanical principles. This substitutes a potentially complex control system with a straightforward mechanical constraint, reducing overall device complexity while achieving the reliability goal.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 mechanism ensures reliable, precise, and robust operation with minimal unlocking stroke, preventing accidental activation and enabling integration into diverse objects for multiple functional applications.

Implementation Method 1

The holding means comprise a permanent magnet and a ferromagnetic material integrated respectively at the level of the support surface and at the level of the retaining member or vice versa so that the support surface exerts an attraction force on the retainer

Methodology Applied
Scientific EffectMagnetic attraction force: Magnetism

Data Source

PatentEP3799608B1Briefcase with retractable mechanism
Publication Date: 2022.11.16 PA COTTE SA
  • EP3799608B1 patent drawingFigure 1~2
  • EP3799608B1 patent drawingFigure 3~5
  • EP3799608B1 patent drawingFigure 6~8

AI summary

The invention relates to a retractable mechanism (10) having a frame (20), a retractable housing (12) configured to take up a retracted position, in which the retractable housing (12) is locked in the frame, and an extended position with respect to the frame, and an actuator (25). The actuator comprises a camway (30) arranged on the retractable housing (12), a cam follower (39) secured to a rocker (34) arranged in the frame, and a pusher (40) for moving the retractable housing (12) from its retracted position into its extended position when the retractable housing is unlocked. The camway (30) has a locking portion (30a), in which the cam follower (39) is arranged when the retractable housing (12) is locked in its retracted position. The actuator (25) also has a retention member (46) designed to prevent the cam follower (39) from leaving the locking portion (30a) of the camway (30) as long as the force exerted on a support wall (13) of the retractable housing (12) does not exceed a predetermined threshold value so as to prevent inadvertent unlocking of the retractable mechanism.