Bayonet Lens Mount Layout for Stable Lock Pin Engagement

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Solution Overview

Problem

Existing camera lens mount systems face instability when external forces are applied or the orientation of the interchangeable lens assembly changes, due to uneven dispositional relationships between bayonet claw portions and the lock pin groove, leading to potential detachment issues.

Innovation Solution

The lens mount system is designed with a specific configuration where the bayonet claw portions are disposed such that the angle relationships between the lock pin groove and the claw portions are balanced, ensuring a stable mounting even under external forces and orientation changes, using a lock pin that applies biasing force to maintain the assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bayonet claw portions are disposed with uneven angular relationships to the lock pin groove, then the structure is simpler to manufacture, but the mounting stability deteriorates when external forces are applied

Engineering Contradiction:
Improveease of manufactureVSAvoidmounting stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by deliberately designing unequal angular relationships between the bayonet claw portions and the lock pin groove. Specifically, the first bayonet claw portion is positioned at a first angle from the lock pin groove, while the second bayonet claw portion is positioned at a second angle that is intentionally different from the first angle. This asymmetric arrangement optimizes the distribution of mechanical stresses and enhances mounting stability under external forces, directly resolving the contradiction between manufacturing simplicity and mounting reliability.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the lock pin applies strong biasing force to secure the lens assembly, then the mounting reliability improves, but the risk of tilting under external forces increases

Engineering Contradiction:
Improvemounting reliabilityVSAvoidanti-tilting stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses asymmetric angular positioning of the bayonet claw portions relative to the lock pin groove to balance the forces applied by the lock pin. The different angles allow the claw portions to distribute the biasing force more evenly, preventing concentrated stress that would cause tilting while maintaining secure mounting.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent achieves equipotentiality by positioning the bayonet claw portions at specific angles that create a balanced force distribution system. This arrangement ensures that the lock pin's biasing force is evenly distributed across both claw portions, creating a stable equilibrium that prevents tilting while maintaining reliable mounting under various orientations and external forces.

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP3686669B1Lens mount, lens apparatus, accessory, image pickup apparatus, and camera system
Publication Date: 2023.12.13 CANON KK
  • EP3686669B1 patent drawingFigure 1
  • EP3686669B1 patent drawingFigure 2
  • EP3686669B1 patent drawingFigure 3A~3B

AI summary

An interchangeable lens assembly (100) including a plurality of lens-side claw portions (107a, 107b, 107c) configured to enable engagement with a plurality of camera-side claw portions, and a lock pin groove portion (102) in which a lock pin (203) is inserted; wherein θ1 is an angle formed between a line passing a fifth lens-side end (107c1) and an optical axis O, and a line passing a center of a lock pin groove portion and the optical axis O, and θ2 is an angle formed between a line passing a fourth lens-side end (107b2) and the optical axis O, and a line that passing the center of the lock pin groove portion and the optical axis O; wherein θ1 and θ2 satisfy a predetermined conditional expression; and corresponding lens apparatus, camera mount, image pickup apparatus and camera system.