Rounded Cam Follower Geometry for Impact-Resistant Zoom Lenses

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Solution Overview

Problem

Conventional zoom lenses are prone to damage from impacts, especially when coupled to devices that experience significant forces like firearms, leading to deformation of the cam groove and difficulties in smooth zoom operations.

Innovation Solution

A cam follower with a cuboid body and cylindrical segments, designed to increase the area of contact with the cam groove upon impact, reducing damage by deforming and distributing the force effectively, and featuring radii of curvature that enhance impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If hard materials are used to improve the strength of the cam groove, then the strength of the cam groove is improved, but the device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvestrength of the cam grooveVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention changes the geometric parameters of the cam follower by providing a rounded corner with a specific radius of curvature (R1) that is greater than the distance from the center of the top surface to the corner. This parameter change allows the rounded corner to deform and increase contact area during impact, protecting the cam groove without requiring harder materials or more complex structures.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the cam follower is made with a standard sharp-cornered cuboid shape, then the manufacturing precision is easier to achieve, but the cam groove gets damaged during impact

Engineering Contradiction:
Improveease of manufactureVSAvoiddamage to the cam groove
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention applies curvature to the corner of the cam follower by providing a rounded corner with a specific radius of curvature (R1). This curved geometry allows the corner to deform during impact, increasing the contact area with the cam groove wall and distributing the impact force, thereby preventing damage to the cam groove while remaining manufacturable.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If the zoom lens is coupled to a firearm, then the adaptability of the zoom lens is improved, but the reliability of smooth zoom operation decreases due to impact forces

Engineering Contradiction:
Improveadaptability to firearm couplingVSAvoidreliability of smooth zoom operation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention provides beforehand cushioning by designing the cam follower with a rounded corner that is specifically configured to deform during impact. This pre-designed deformation capability allows the cam follower to absorb and distribute impact forces from firearm coupling before they can damage the cam groove, ensuring reliable smooth zoom operation under harsh conditions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 cam follower effectively reduces and prevents damage to the cam groove during impacts, ensuring smooth zoom operations and maintaining alignment with the firearm's bore sight, even under harsh conditions.

Implementation Method 1

the first radius of curvature is selected such that if the zoom lens experiences an impact, at least one of the first pair of surfaces will deform due to contact with at least one of the side walls of the first cam groove and increase its area of contact with the side wall of the first cam groove

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3717949B1Cam follower and a zoom lens therefor
Publication Date: 2023.07.05 COPENHAGEN SENSOR TECH AS
  • EP3717949B1 patent drawingFigure 1
  • EP3717949B1 patent drawingFigure 2
  • EP3717949B1 patent drawingFigure 3

AI summary

The present disclosure relates to a cam follower for a zoom lens, in particular a cam follower that is optimized for reduced damages to a zoom lens, for example if the zoom lens experiences an impact.