Linear Damper Unit for Rotatable Sheet Stacker
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Solution Overview
Problem
Existing image reading apparatuses face challenges in downsizing and cost reduction due to the need for a gear train to generate sufficient torque for rotary dampers to decelerate falling original trays, leading to potential noise and damage.
Innovation Solution
Incorporating a damper unit with a cylinder portion and piston portion that expands and contracts to suppress the speed of a rotatable member, such as an original tray, by contacting a contact portion, eliminating the need for a gear train and allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gear train is used to generate sufficient torque for the rotary damper, then the damper can effectively decelerate the falling original tray, but the apparatus size increases and cost increases
Solution Approach 1:
The patent extracts and eliminates the gear train from the system by redesigning the damper activation mechanism. Instead of using a rotary damper that requires gear reduction, the invention uses a linearly moving damper unit that is directly actuated by the original tray's downward movement through a contact portion, removing the need for complex gear mechanisms while maintaining deceleration effectiveness
Solution Approach 2:
The patent replaces the rotary mechanical system (rotary damper with gear train) with a linear mechanical system (linearly moving damper unit). The damper unit moves linearly in response to the original tray's movement, substituting the rotary-mechanical-gear system with a simpler linear-mechanical system that achieves the same deceleration function without requiring gear reduction
2Force
If a gear train is configured to increase rotational speed of the rotary damper, then sufficient torque is generated, but the apparatus becomes larger and more expensive
Solution Approach 1:
The patent removes the gear train configuration entirely by using a linearly moving damper unit that generates the necessary force directly through its linear motion. The damper unit is activated by the contact portion that moves linearly as the original tray falls, eliminating the need for gear mechanisms that would otherwise be required to generate sufficient torque
Solution Approach 2:
The patent substitutes the rotary mechanical system requiring torque multiplication through gears with a linear mechanical system. The linearly moving damper unit generates the necessary deceleration force directly through its linear motion, replacing the rotary-gear system and achieving the same force-generation function without mechanical complexity
3Productivity
If the original tray is allowed to fall freely for quick access, then operation speed increases, but noise and potential damage occur
Solution Approach 1:
The patent implements beforehand cushioning by providing a damper unit that is pre-positioned to activate during the original tray's downward movement. The damper unit is arranged to engage with the contact portion before the tray completes its fall, providing progressive resistance that cushions the deceleration process and prevents violent impact with the discharge tray, thereby reducing noise and potential damage while maintaining quick access capability
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 reduces the lowering speed of rotatable members, preventing noise and damage, while enabling a more compact and cost-effective image reading apparatus.
Implementation Method 1
a damper unit mounted in either one of the main assembly and the rotatable member and including a cylinder portion and a piston portion inserted into the cylinder portion, wherein the damper unit is configured to be expanded in an expansion direction and to be contracted in a contraction direction by sliding the cylinder portion and the piston portion relative to each other
Data Source
AI summary
An image reading apparatus includes an image reading portion; a main assembly; a rotatable member; a damper unit mounted to either one of the main assembly and the rotatable member and including a cylinder portion and a piston portion inserted into the cylinder portion, wherein the damper unit is expanded in an expansion direction and contracted in a contraction direction by sliding the cylinder portion and the piston portion relative to each other; and a contact portion provided on the other one of said main assembly and said rotatable member and configured to contact said damper unit, wherein the damper unit suppresses a speed of said rotatable member when said rotatable member lowers from an upper position toward a lower position in a state in which the contact portion contacts and presses the damper unit in the contraction direction.