Lens Barrel Cam Ring Locking Against External Force Damage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing lens barrels are prone to deformation or damage from external forces, which can degrade their driving performance.

Innovation Solution

A lens barrel design featuring a cam ring with first and second contact portions that restrict rotation when subjected to external forces, combined with a guide barrel and fixed member, to prevent deformation and maintain driving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rotation of the cam ring is stopped to prevent damage to the gear, then the gear is protected from damage, but the cam grooves or cam followers may be deformed or damaged due to receiving most of the external force

Engineering Contradiction:

Improvegear strengthVSAvoidcam groove reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

A buffer member is introduced as an intermediary component between the cam ring and the cam followers. This buffer member absorbs and distributes the external force, preventing direct transmission of impact forces to the cam grooves and cam followers. The buffer member acts as a mediator that protects the precision components from deformation while allowing the cam ring rotation to be restricted during impact events.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the cam ring is designed to restrict rotation under external force, then driving performance is maintained, but the structure becomes more complex

Engineering Contradiction:

Improvedriving performanceVSAvoidcam ring structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The buffer member is integrated with the existing cam ring structure, merging the impact absorption function with the rotation restriction function. The buffer member is positioned within the cam ring's internal structure, combining multiple protective functions into a single integrated component rather than adding separate independent mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The buffer member serves multiple functions simultaneously: it absorbs external impact forces, restricts cam ring rotation during impact events, and protects the cam grooves and cam followers from deformation. This multi-functional design achieves reliable driving performance protection without proportionally increasing structural complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12535647B2Lens barrel capable of preventing deformation or damage caused by external force and optical apparatus

Publication Date: 2026.01.27 CANON KK

AI summary

A lens barrel includes a lens and a holding member holds the lens. A guide barrel guides the holding member linearly movably in an optical axis direction of the lens. A cam ring is rotatably held about an optical axis of the lens with respect to the guide barrel and surrounds the guide barrel. The cam ring has a first contact portion opposed to the fixed member fixed to the guide barrel, in the optical axis direction. The fixed member has a second contact portion opposed to the first contact portion in the optical axis direction. When the cam ring is moved by an external force to approach the fixed member in the optical axis direction, the first contact portion and the second contact portion are brought into contact with each other, whereby rotation of the cam ring about the optical axis is restricted.