Lens Barrel Cam Cylinder Thickness Reduction via Overlapping Grooves
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Solution Overview
Problem
Existing lens barrels face challenges in minimizing the thickness of cam cylinder frames with cam grooves on both inner and outer peripheries while preventing disengagement of cam followers, particularly under conditions like falling, which affects the structural integrity and functionality.
Innovation Solution
A lens barrel design featuring a cam cylinder frame with overlapping cam grooves on the inner and outer peripheries, where the thickness is minimized by ensuring the cam followers have non-contact portions and specific angular displacements to avoid collisions, allowing for increased groove depths without increasing the overall thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the cam cylinder frame is decreased to minimize lens barrel size, then the overall dimensions are reduced, but the cam followers may disengage from the cam grooves under external forces such as falling
Solution Approach 1:
The patent transitions from a single-layer cam groove design to a multi-layer overlapping structure where cam grooves are arranged in different radial layers. This dimensional reorganization allows the cam followers to be engaged by multiple grooves simultaneously, providing redundant engagement paths that maintain reliability even when the frame thickness is reduced.
Solution Approach 2:
The cam grooves are nested in an overlapping manner where the first cam groove and second cam groove are positioned such that their engagement zones overlap radially. This nesting arrangement allows multiple grooves to share the same spatial envelope, enabling the system to maintain strong follower engagement while minimizing the overall radial thickness of the cam cylinder frame.
2Strength
If the depth of cam grooves is increased to prevent disengagement, then the engagement strength is improved, but the radial thickness of the cam cylinder frame must be increased
Solution Approach 1:
Instead of increasing groove depth in a single radial direction, the patent distributes the engagement function across multiple radial layers with overlapping grooves. This allows the system to achieve equivalent or superior engagement strength while maintaining a compact radial profile, as the overlapping structure utilizes angular and circumferential dimensions to provide mechanical advantage.
Solution Approach 2:
The first cam groove and second cam groove are merged in space to create an overlapping engagement zone. This merging allows the cam followers to be engaged by multiple grooves simultaneously, combining the strength benefits of deep grooves with the space efficiency of a thin frame structure.
3Volume of moving object
If overlapping cam grooves are implemented to reduce thickness, then the radial space is optimized, but the risk of cam follower collision increases
Solution Approach 1:
The patent applies different functional characteristics to different regions of the cam follower and groove system. The non-contact portions are strategically positioned in zones where collision risk exists, while contact portions are positioned in safe zones. This local differentiation allows the overlapping groove structure to provide thickness reduction benefits without compromising follower safety.
Solution Approach 2:
The design proactively addresses the collision risk by incorporating non-contact portions that prevent harmful interactions before they can occur. By anticipating potential collision scenarios and designing the groove-follower geometry to avoid them, the system eliminates the harmful effect rather than reacting to it after collision occurs.
Data Source
AI summary
A lens barrel has a rotary frame, lens group frame, and shutter frame. The rotary frame has first and second cam grooves respectively on inner and outer peripheries as viewed in a radial direction. A first cam follower of the lens group frame and a second cam follower of the shutter frame are respectively engaged with the first and second grooves. A radial direction size the rotary frame is smaller than a sum of depths of the first and second grooves. The rotary frame includes a first region W1 only with the first groove, a region W0 with first and second grooves, and a region W2 only with the second groove. Positions of the first and second followers differ in a circumferential direction. At least one of the first and second followers has a non-contact portion not contacting with a groove wall of the corresponding groove in the region W0.