Hinge Mechanism for Automatic Document Feeder Axial Retention
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Solution Overview
Problem
Conventional image readers with automatic document feeders require significant effort to open and close the document presser due to the weight of the feeder, especially in the document stationary method, necessitating assistance from elastic members to reduce the workload.
Innovation Solution
A hinge mechanism comprising a pair of hinge units with a hinge base, a hinge upper member, and a shaft that restricts axial movement, allowing the automatic document feeder to be opened and closed in up and down directions, utilizing a groove on the shaft to engage with a rib on the feeder, providing a biasing force for easy operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the automatic document feeder is made heavy to provide stable support and sufficient urging force, then the stability and urging force are improved, but the effort required to open and close the document presser increases
Solution Approach 1:
The hinge mechanism is divided into multiple components: hinge base, hinge upper member, shaft, and elastic member. This segmentation allows the heavy automatic document feeder to be supported by a complex hinge mechanism rather than a simple heavy hinge, distributing the force requirements across multiple elements and enabling the presser to open and close easily despite the feeder's weight.
2Ease of manufacture
If the shaft is made loose-fitting in the hinge base and hinge upper member, then the ease of assembly is improved, but the risk of the shaft coming off during operation increases
Solution Approach 1:
A groove is introduced as an intermediary feature on the shaft that engages with a corresponding rib on the hinge upper member. This groove-rib interface acts as a mechanical intermediary that prevents the shaft from coming off during operation while still allowing straightforward assembly, eliminating the need for complex retention mechanisms.
3Reliability
If the shaft is tightly fitted in the hinge base and hinge upper member, then the shaft retention is improved, but the ease of assembly and disassembly deteriorates
Solution Approach 1:
The groove-rib engagement serves as a mechanical intermediary that provides reliable shaft retention without requiring tight interference fits. The groove on the shaft engages with the rib to prevent disengagement during operation, while the overall hinge unit can still be easily assembled and disassembled by simply removing the hinge upper member from the hinge base.
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 hinge mechanism reduces the effort required to open and close the document presser, allowing for smooth and controlled movement of the automatic document feeder, enhancing user convenience and preventing the shaft from coming off during operation.
Implementation Method 1
there has been known a hinge mechanism configured such that, in a state where a document cover (a document presser) is closed, a load torque that biases the document cover in an opening direction remains in a hinge unit
Data Source
AI summary
A hinge mechanism of the present disclosure includes a pair of hinge units each having a hinge base, a hinge upper member, and a shaft, and the hinge mechanism holds an automatic document feeder to be openable/closable in up/down directions with respect to an image reading unit. The hinge base is supported on the image reading unit which reads a document image. The hinge upper member is supported on the automatic document feeder which feeds a document to the image reading unit. The shaft pivotably couples the hinge base and the hinge upper member together. By attaching the hinge upper member to the automatic document feeder, a groove formed in a circumferential surface of the shaft in an annular shape in a circumferential direction of the shaft and a rib provided on the automatic document feeder engage with each other, whereby axial movement of the shaft is restricted.