Toggle Lock Mechanism Eliminates Abnormal Noise at Neutral Point
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Solution Overview
Problem
Conventional image forming apparatuses with toggle mechanisms experience abnormal noise due to engagement backlash cancellation at the neutral point of the lock member, making them less usable.
Innovation Solution
A lock mechanism with a rotatable lock member and a biasing member that switches the rotation moment from pushing to pulling the engagement member towards the locking position, ensuring the lock member sandwiches the engagement member before the neutral point is reached, eliminating the engagement backlash and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a toggle mechanism is used to automatically lock the cover, then the ease of operation is improved, but abnormal noise is generated due to engagement backlash cancellation at the neutral point
Solution Approach 1:
The lock member is designed to sandwich the engagement member before the toggle mechanism reaches its neutral point. This preliminary engagement prevents the engagement member from becoming loose or detached during the toggle operation, thereby eliminating the collision and abnormal noise that would otherwise occur when the engagement backlash is cancelled at the neutral point.
2Device complexity
If a lever operation mechanism is used, then the lock mechanism is simple, but the usability is poor due to difficulty in identifying handle position and operating direction
Solution Approach 1:
The lock mechanism is designed to operate automatically without requiring user intervention. The toggle mechanism self-activates when the cover is opened or closed, and the lock member automatically sandwiches the engagement member before the neutral point is reached. This eliminates the need for users to identify handle positions or operating directions, thereby improving usability while maintaining simplicity.
3Productivity
If the lock member passes through the neutral point of the toggle mechanism, then the lock/unlock operation is completed, but engagement backlash is cancelled abruptly causing collision noise
Solution Approach 1:
The lock member performs the engagement action before the toggle mechanism reaches its neutral point. By sandwiching the engagement member in advance, the system prevents the abrupt cancellation of engagement backlash that occurs at the neutral point, thereby eliminating collision noise while maintaining efficient lock operation.
Solution Approach 2:
The lock member is designed to maintain continuous contact with the engagement member throughout the toggle operation, including the critical region near the neutral point. This continuous engagement acts as a cushioning mechanism that prevents abrupt backlash cancellation and the resulting collision noise, while still allowing rapid lock operation.
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 effectively prevents collision sounds and maintains usability by ensuring the engagement member is pressed and sandwiched before the neutral point, thus eliminating engagement backlash and noise.
Implementation Method 1
a biasing member (13) that biases the lock member (60)
Implementation Method 2
the lock member is rotated by being pressed by the engagement member when the opening-closing member is closed relative to the apparatus body
Data Source
AI summary
An image forming apparatus and a lock mechanism including a toggle mechanism capable of eliminating the problem of abnormal noise before and after a lock member passes a neutral point are provided. A lock mechanism includes a toggle spring that rotationally biases a toggle lever toward a standby position when the lever is between a standby position and a neutral point, and implements switching in a direction of the rotational biasing toward a locking position after the lever passes the neutral point. A projection and a locked portion of an engagement member are sandwiched by a toggle base and the toggle lever to maintain a contact state before and after the toggle lever passes the neutral point.