Hook Locking Mechanism for Image Forming Apparatus
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Solution Overview
Problem
Conventional locking mechanisms for movable units in image forming apparatuses, such as electrophotographic copiers and laser printers, face challenges in maintaining effective engagement and disengagement forces, leading to reduced locking strength and operational efficiency.
Innovation Solution
A locking mechanism comprising a hook with a supporting portion pivotably supported on a unit main body, an engaging portion protruding from the supporting portion, and a biasing member that biases the hook to engage with an engaged portion, where the engaging and engaged portions interact with specific faces to optimize engagement strength without increasing the biasing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the biasing force of the hook is increased to improve locking strength, then the engagement strength between hook and stopper is improved, but the horizontal load required for disengagement increases
Solution Approach 1:
The engaging portion of the hook is designed with a curved surface (arc-shaped engagement surface) that contacts the stopper. This curvature allows the engagement force to be applied more effectively while reducing the horizontal component of the disengagement force, thereby maintaining strong locking without requiring excessive horizontal load for release.
Solution Approach 2:
The patent modifies the geometric parameters of the hook, specifically the angle and shape of the engaging portion. By optimizing the curvature radius and angular orientation of the engagement surface, the locking strength is enhanced while the horizontal force component during disengagement is minimized, resolving the contradiction between strong locking and easy release.
2Force
If the biasing force of the hook is decreased to reduce disengagement load, then the horizontal load for disengagement is reduced, but the engagement strength between hook and stopper deteriorates
Solution Approach 1:
The curved engagement surface of the hook is designed to optimize the force transmission angle. This curvature ensures that even with reduced biasing force, the engagement strength is maintained by directing the force more effectively along the engagement interface, while still allowing easy disengagement with minimal horizontal load.
3Ease of manufacture
If the first face of the hook is made parallel to the second face to simplify structure, then the manufacturing complexity is reduced, but the engagement strength and locking performance deteriorate
Solution Approach 1:
The hook features a curved engagement surface (arc-shaped first face) that provides superior engagement strength and locking performance compared to parallel flat faces. This curvature is manufactured as a single integrated feature on the hook, maintaining ease of manufacture while significantly improving the engagement characteristics and overall locking reliability.
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 mechanism enhances engagement strength between the hook and stopper, allowing for improved locking without increasing the biasing force, while maintaining operability and reducing the horizontal load required for disengagement, thus improving the overall locking performance.
Implementation Method 1
a biasing member which biases the hook in such a direction as to let the engaging and engaged portions engage
Data Source
AI summary
A locking mechanism includes a hook, an engaged portion, and a biasing member, and locks a movable unit supported on a unit main body to the unit main body. The hook has a supporting portion pivotably supported on the unit main body and an engaging portion protruding from the supporting portion. The engaged portion is formed on the movable unit and is engageable with the engaging portion. A biasing member biases the hook in such a direction as to let the engaging and engaged portions engage. The hook has a first face facing the engaged portion at the tip end of the engaging portion and a second face extending from the first face toward the supporting portion and inclined relative to the first face in such a direction as to recede from the pivot. With the engaging and engaged portion in engagement, the engaged portion touches only the second face.