Focal Plane Shutter Iron Scrap Arcuate Mounting
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Solution Overview
Problem
Focal plane shutters with electromagnets face issues where the iron scrap member may not maintain tight contact with the electromagnet, leading to premature shutter blade operation due to tilting, which can result in incorrect exposure timing and potential damage to the mounting hole edges.
Innovation Solution
A focal plane shutter design featuring an iron scrap member with a shaft and flange, where the shaft is fitted into a mounting hole with an arcuate surface and a collar member, allowing smooth tilting and preventing contact with the outer peripheral portion, ensuring stable exposure operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the iron scrap member is mounted to the driving member with a simple shaft and mounting hole configuration, then the device complexity is reduced, but the iron scrap member may tilt when brought into contact with the electromagnet, causing insufficient sucking and holding force and premature shutter blade operation
Solution Approach 1:
The mounting hole edge is formed with an arcuate surface that protrudes toward the collar member. This curved surface allows the shaft to tilt smoothly in the radial direction when the iron scrap member is brought into contact with the electromagnet, preventing the flange from damaging the mounting hole edge while maintaining stable contact between the iron scrap portion and electromagnet.
Solution Approach 2:
The mounting configuration is divided into separate functional components: the shaft for insertion and tilting, the flange for limiting axial movement, and the collar member for guiding radial tilting. This segmentation allows each component to perform its specific function independently, enabling reliable contact stability without excessive overall complexity.
2Force
If the shaft of the iron scrap member is tilted to ensure tight contact with the electromagnet, then the sucking and holding force is improved, but the flange may abut and damage the edge of the mounting hole
Solution Approach 1:
The collar member acts as an intermediary between the shaft and the mounting hole edge. When the shaft tilts radially, the collar member guides this motion and prevents the flange from directly contacting and damaging the mounting hole edge, while still allowing sufficient tilting for tight contact between the iron scrap portion and electromagnet.
Solution Approach 2:
The arcuate surface on the mounting hole edge is formed in advance to accommodate the tilting motion. This pre-designed curved path prevents the flange from striking the mounting hole edge during operation, cushioning against potential damage before it can occur.
3Duration of action of stationary object
If the edge of the mounting hole is formed with an arcuate surface to prevent damage, then the durability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The arcuate surface is designed to work with the dynamic tilting motion of the shaft during operation. Rather than requiring extremely precise static positioning, the curved surface accommodates the natural tilting movement, allowing for reasonable manufacturing tolerances while ensuring proper function and durability.
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 design ensures that the iron scrap member maintains tight contact with the electromagnet, preventing premature shutter blade operation and minimizing damage to the mounting hole edges, thereby ensuring accurate and stable exposure timing.
Implementation Method 1
an electromagnet starts sucking and holding the iron scrap member when the coil of the electromagnet is energized
Data Source
AI summary
A focal plane shutter for cameras includes: a shutter blade assembly; an electromagnet assembly; driving means that includes a mounting member mounted with an iron scrap member that cooperates with an iron core member of the electromagnet assembly; and a setting member that operates the driving means to a set position. The iron scrap member includes a shaft fitted in a mounting hole of the mounting member, an iron scrap portion provided at one end of the shaft and brought into contact with the iron core member, and a removal preventing flange provided at the other end of the shaft, a collar member is fitted to the shaft between the mounting hole and the flange, an edge of the mounting hole is formed to have an arcuate surface protruding toward the collar member, and the collar member is formed to have, on the edge side, an arcuate surface protruding toward the flange and substantially perpendicular to the arcuate surface.