Asymmetric Lens Mount Layout for Stable Interchangeable Lens Locking

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Solution Overview

Problem

Existing camera systems face challenges in maintaining a stable mount of interchangeable lenses due to uneven dispositional relationships between bayonet claw portions, leading to instability under external forces and orientation changes.

Innovation Solution

The design of a lens mount with specifically angled bayonet claw portions and a lock pin mechanism that ensures a balanced and secure attachment to the camera body, utilizing a lock pin groove and biasing members to maintain stability across various orientations and forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bayonet claw portions are positioned near the lock pin groove portion, then the lens assembly can be securely locked to the camera body, but the dispositional relationship between the bayonet claw portions and the lock pin groove portion differs greatly, leading to instability under external forces

Engineering Contradiction:
Improvemounting stabilityVSAvoidmounting stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies asymmetry by intentionally designing unequal angular relationships between the bayonet claw portions and the lock pin groove portion. Specifically, the first bayonet claw portion is positioned at a first angle from the lock pin groove portion, while the second bayonet claw portion is positioned at a second angle that is deliberately different from the first angle. This asymmetric arrangement creates a balanced force distribution that prevents tilting and enhances mounting stability under external forces.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the lock pin is inserted into the lock pin groove portion to secure the lens assembly, then the lens can be firmly attached, but the lens assembly becomes difficult to remove without retracting the lock pin

Engineering Contradiction:
Improveattachment securityVSAvoidlens removal
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies dynamics by designing the lock pin as a movable component that can transition between extended and retracted positions. The lock pin is biased by a spring mechanism, allowing it to automatically extend to secure the lens assembly during mounting, and can be manually retracted to enable easy removal. This dynamic design provides both secure attachment during use and convenient removal when needed.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the bayonet claw portions are positioned to allow easy insertion and rotation, then the lens assembly can be quickly mounted, but the dispositional relationship creates instability when external forces or orientation changes are applied

Engineering Contradiction:
Improvemounting speedVSAvoidmounting stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent resolves this contradiction by using asymmetric positioning of the bayonet claw portions relative to the lock pin groove portion. The unequal angular relationships (first angle and second angle) create a force-balanced configuration that maintains stability under external forces while still allowing easy insertion and rotation during the mounting process.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3696604B1Lens mount, lens apparatus, accessory, image pickup apparatus and camera system
Publication Date: 2024.11.13 CANON KK
  • EP3696604B1 patent drawingFigure 1
  • EP3696604B1 patent drawingFigure 2
  • EP3696604B1 patent drawingFigure 3A~3B

AI summary

A lens mount (101) includes a plurality of lens-side claw portions (107a, 107b, 107c) and a lock pin concave portion (102) wherein, the internal angles of a quadrangle formed by connecting a center of a first lens-side claw portion (107a), a center of a second lens-side claw portion (107b), a center of a third lens-side claw portion (107c), and a center of the lock pin concave portion (102) satisfy predetermined conditions, and corresponding lens apparatus, accessory, camera mount, image pickup apparatus and camera system.