Variable-Force Spring Mechanism for Paper Stacking
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Solution Overview
Problem
Existing paper-sheet stacking apparatuses face difficulties in handling thick paper sheets, as the constant pressure applied by the backup plate can cause it to flick, preventing proper stacking, while increasing pressure to handle thick sheets leads to increased pressure on the pushing roller, making it hard to feed paper sheets.
Innovation Solution
A paper-sheet stacking apparatus with a variable-force spring mechanism that applies a higher spring force initially to prevent flicking of thick sheets and gradually reduces the force as more sheets are stacked, combined with guide ribs made of high and low-friction materials to manage sheet placement and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure applied to the backup plate is increased to prevent flicking of thick paper sheets, then the reliability of stacking thick sheets is improved, but the pressure on the pushing roller increases making it difficult to feed paper sheets
Solution Approach 1:
The patent applies a variable spring force mechanism that dynamically adjusts the backup plate's opposing force based on the stacking state. In the initial stacking phase, the spring force is stronger to prevent flicking of thick sheets. In the middle stacking phase, the spring force becomes weaker to reduce pressure on the pushing roller and facilitate smooth feeding. This dynamic adjustment resolves the contradiction between stacking reliability and feeding ease.
Solution Approach 2:
The patent divides the stacking process into distinct phases (initial stacking phase and middle stacking phase) with different force requirements. By periodically changing the spring force characteristics according to the stacking progress, the system optimizes performance for each phase: strong force initially to handle thick sheets, then reduced force to facilitate continuous feeding.
2Device complexity
If the pressure applied to the backup plate is constant, then the device complexity is reduced, but the backup plate may flick when handling thick paper sheets
Solution Approach 1:
The patent changes the force parameter of the backup plate from constant to variable by introducing a spring mechanism with different force characteristics in different phases. The spring force naturally varies based on compression distance, providing stronger force initially and weaker force later, thereby preventing flicking while maintaining reasonable device complexity through the use of elastic mechanics.
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
Enables stable stacking of paper sheets of various types and sizes by preventing flicking in the initial phase and moderating pressure in the middle phase, ensuring continuous and efficient stacking without disrupting the feeding process.
Implementation Method 1
a variable-force spring mechanism that applies a higher spring force initially to prevent flicking of thick sheets and gradually reduces the force as more sheets are stacked
Implementation Method 2
a part located with the first distance (D1) is made of a high-friction material
Implementation Method 3
a part located within the second distance (D2) is made of a low-friction material that offers less frictional resistance than the high-friction material
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
According to one embodiment, a paper-sheet stacking apparatus includes a holding unit (20), a pushing mechanism (40), a backup (54), and a variable-force spring mechanism (60). The holding unit has a stacking base for holding a plurality of paper sheets in standing position and is configured to stack the paper sheets, one laid on another in a direction of a plane. The pushing mechanism is configured to push paper sheets transported, into the holding unit. The backup opposed to the pushing mechanism, is able to move in the direction the paper sheets are stacked and is configured to hold any paper sheet stacked between the backup and the pushing mechanism and to move away from the pushing mechanism as paper sheets are stacked one after another. The variable-force spring mechanism is configured to bias the backup toward the pushing mechanism.