Retard Roller Joint Geometry for Stable Sheet Separation
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Solution Overview
Problem
Existing sheet feeding apparatuses experience fluctuations in separating pressure due to friction between pins and holes or notches, leading to potential delays and jamming issues in sheet conveyance.
Innovation Solution
A sheet feeding apparatus design featuring a joint with specific engagement positions for pins and groove portions on the drive and retard shafts, where the angle between engagement positions is optimized to minimize frictional fluctuations, ensuring stable retard pressure and reducing the likelihood of conveyance failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pins are press-fit through long holes or notch grooves in the coupling to connect drive shaft and retard shaft, then rotary drive force can be transmitted from drive shaft to retard shaft, but friction between pins and holes/grooves causes fluctuation in separating pressure applied by retard roller to feed roller
Solution Approach 1:
The patent changes the geometric parameters of the engagement structure by specifying that the angle between the first straight line (passing through first engagement position and drive input shaft center) and the second straight line (passing through second engagement position and retard shaft center) must be within 80-100 degrees. This parameter optimization minimizes frictional fluctuations during rotation, reducing separating pressure variation to 5% or less while maintaining effective power transmission.
2Ease of operation
If the coupling is inclined with respect to the drive shaft and retard shaft during rotation, then the pins slide against the long hole or notch groove, but this inclination causes significant fluctuation in separating pressure leading to sheet conveyance failures
Solution Approach 1:
The patent optimizes the angular parameter of the engagement positions to minimize harmful friction effects. By constraining the angle between the two straight lines to 80-100 degrees, the design reduces the inclination-induced friction fluctuations during rotation, thereby minimizing separating pressure variation and preventing sheet conveyance failures such as delays and jamming.
3Power
If separating pressure fluctuates greatly due to friction in the joint mechanism, then sheet separation and conveyance may be delayed or jammed, but increasing engagement friction improves torque transmission
Solution Approach 1:
The patent finds an optimal angular parameter range (80-100 degrees) that balances torque transmission efficiency with smooth sheet conveyance. This angle optimization ensures sufficient friction for reliable torque transmission from drive shaft to retard shaft while minimizing excessive friction that would cause separating pressure fluctuations and conveyance failures, thus maintaining both power transmission and productivity.
Data Source
AI summary
A sheet feeding apparatus includes a sheet conveyance roller, a retard roller to contact the conveyance roller and separate sheets one by one, a drive input shaft, a retard shaft, and a joint to connect the retard shaft with the drive input shaft and transmit rotary drive force of the drive input shaft to the retard shaft. A first angle formed between a line passing through a first engagement position and the drive input shaft and a line passing through a second engagement position and the retard shaft center is within a range of 80 degrees or greater and 100 degrees or smaller, and a second angle formed between a line passing through the drive input shaft and a first pin axis and a line passing through the retard shaft and a second pin axis is within a range of 50 degrees or greater and 70 degrees or smaller.