Gear Coupling Play Elimination in Sheet Folding Devices
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Solution Overview
Problem
Existing sheet folding devices experience paper wrinkles and looseness due to differences in peripheral speeds between rollers, particularly when using gear coupling mechanisms with parallel pins, which can lead to inefficiencies in the folding process.
Innovation Solution
The implementation of a sheet folding device with a second gear coupling mechanism featuring projection portions on the inner side walls of the gear groove, which ensures close contact between the parallel pin and the gear, eliminating play and maintaining rotational force transmission, thereby preventing paper wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gear coupling mechanism with parallel pins is used to drive the rollers, then the rollers can rotate in conjunction with each other, but play between the parallel pins and gear grooves causes paper wrinkles and looseness in the folded sheets
Solution Approach 1:
The patent applies local quality by creating projection portions on specific inner side walls of the gear groove at strategic locations. These projection portions locally enhance the contact and engagement between the parallel pin and gear groove, eliminating play only where needed while maintaining the overall gear coupling mechanism structure.
Solution Approach 2:
The projection portions are pre-formed on the gear groove inner side walls to eliminate play between the parallel pin and gear groove before the rollers begin operation. This preliminary structural configuration ensures that no play-induced paper wrinkles or looseness occur during the folding process.
2Productivity
If the first roller rotates at a higher peripheral speed than the second roller to improve folding efficiency, then the folding process becomes more efficient, but this speed difference causes paper wrinkles and reduces folding quality
Solution Approach 1:
The patent uses projection portions on the gear groove inner side walls to locally enhance engagement at critical points. This allows the system to maintain different roller peripheral speeds for improved folding efficiency while preventing play-induced wrinkles through enhanced local contact, thus resolving the contradiction between productivity and manufacturing precision.
3Manufacturing precision
If projection portions are added to the gear groove inner side walls to eliminate play, then the gear coupling becomes more precise, but the device complexity increases
Solution Approach 1:
Rather than modifying the entire gear groove structure, the patent adds projection portions only on specific inner side walls where play elimination is most needed. This localized modification achieves precise gear engagement while minimizing the increase in device complexity.
Solution Approach 2:
The projection portions are integrated directly into the gear groove structure, merging the play elimination function with the existing gear coupling mechanism. This integration avoids adding separate components, thus reducing the overall device complexity while still achieving precise engagement.
Data Source
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AI summary
A sheet folding device (73) includes first and second rollers (734, 735), a blade (733), first and second parallel pins (811, 821), and first and second gears (734g, 735g). The first and second parallel pins (811, 821) are passed through first and second pin through-holes (812, 822) penetrating through first and second shaft portions (7340, 7350) in a direction perpendicular to a longitudinal direction of the shaft portions (7340, 7350). The first and second gears (734g, 735g) have first and second shaft through-holes (814, 824) through which the first and second shaft portions (7340, 7350) are passed, and first and second grooves (815, 825) in which the first and second parallel pins (811, 821) are inserted, respectively. Projection portions (826) formed on inner side wall of the second groove (825) and projecting from both sides of the second shaft portion (7350) cause the second parallel pin (821) to closely contact a side wall that is, in the second groove (825), opposite to the projection portions (826), and cause the second parallel pin (821) to closely contact a portion of the second pin through-hole (822).