Focal Plane Shutter Braking Mechanism for High-Speed Durability
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Solution Overview
Problem
Focal plane shutters face challenges in maintaining braking force and endurance due to high operational speeds and increased shooting demands, leading to potential breakage and aperture coverage issues.
Innovation Solution
A focal plane shutter design incorporating a braking mechanism with a brake member and friction-providing means, utilizing coil springs and plate springs to generate a large braking force, where the elastic force of the driving spring actively controls the brake member's rotation, ensuring effective braking and endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If shutter blade units operate at extremely high speed, then productivity is improved, but reliability deteriorates due to breakage and bouncing
Solution Approach 1:
The braking mechanism is activated before the shutter blade units complete their operation, applying braking force in advance to reduce impact. The brake member engages with the driving pin trajectory to provide preliminary deceleration, preventing breakage before it occurs.
Solution Approach 2:
The impact force that would normally cause breakage is converted into useful braking force. The brake member utilizes the kinetic energy of the moving shutter blade units to generate friction-based deceleration, transforming the harmful impact into a beneficial braking action that protects the system.
2Reliability
If braking force is increased to prevent breakage, then reliability is improved, but device complexity increases
Solution Approach 1:
The brake member serves multiple functions: it provides braking force through friction, guides the driving pin along its trajectory, and returns to its initial position through elastic restoration. This multi-functionality reduces the need for additional components, maintaining simplicity while achieving reliable braking.
Solution Approach 2:
The braking mechanism is self-activating through the natural motion of the driving pin. As the driving pin moves along its trajectory, it automatically engages the brake member, which then applies braking force without requiring external control. The system uses its own operational motion to trigger and execute the braking action.
3Reliability
If braking is applied at the stage just before operation completion, then reliability is improved, but loss of time increases due to extended operation cycle
Solution Approach 1:
The braking force is applied partially, only during the critical deceleration phase just before operation completion. The brake member engages briefly to reduce impact velocity, then releases to allow the shutter blade units to complete their motion. This partial application of braking force minimizes time loss while achieving the necessary impact reduction.
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 solution achieves a larger braking force with a simple structure, maintaining performance even under harsh conditions, preventing breakage and aperture coverage issues during high-speed operations.
Implementation Method 1
a friction-providing means which includes at least one plate spring, and by which friction resistant force is applied to the rotation of the brake member
Implementation Method 2
one or two driving springs which are coil springs, one end part of each of which is connected with a shutter blade unit-driving unit, each of which is tensed by rotating the shutter blade unit-driving unit in one direction in the cocking operation of the focal plane shutter, and each of which rotates the shutter blade unit-driving unit in the other direction through the elastic force of the driving spring in shooting
Data Source
AI summary
In a first blade unit-driving unit which is rotated by elastic force of a first blade unit-driving spring in shooting, its driving pin rotates a first brake member counterclockwise and a second brake member clockwise against the elastic force of a coil spring fitted to a fitting shaft and against friction resistance force of a friction-providing part including a plate spring or the like at the final stage of the rotation of the first blade unit-driving unit, the plate spring being fitted to the fitting shaft, so that the first blade unit-driving unit is braked, and, at this point, one end part of the first blade unit-driving spring contacts a part to be pushed of the first brake member and controls the counterclockwise rotation of the first brake member, so that braking force to the first blade unit-driving unit acts on the first blade unit-driving unit larger and more surely.