Steerable Nip Justifier for Mail Edge Registration
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Solution Overview
Problem
Conventional mail sorter machines face challenges in handling variable-sized envelopes due to difficulties in edge justification, as existing mechanisms struggle to apply the necessary force for larger envelopes while avoiding slipping with smaller ones, and require significant lateral shift, leading to potential skewing and issues with postage placement.
Innovation Solution
The implementation of a steerable nip system that rotates to impart lateral velocity to mail pieces, shifting them from bottom to top edge justification, with servo-controlled nips adjusting the shift based on envelope height, and an alternative design using a laterally sliding nip assembly to achieve precise registration without mechanical constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional angled rollers with balls are used for edge justification, then small envelopes can be justified, but large envelopes cannot receive sufficient force for complete justification
Solution Approach 1:
The patent employs a compliant justification wall that can dynamically adapt its position and compliance characteristics. The wall includes compliant elements that allow it to flex and accommodate envelopes of varying sizes, providing appropriate justification force for both small and large envelopes without requiring separate mechanisms for each size category.
Solution Approach 2:
The system changes the physical parameters of the justification wall by making it compliant rather than rigid. This allows the wall to adjust its effective stiffness and position based on the envelope being processed, enabling the same mechanism to handle the full range of envelope sizes from 3.5 inches to 11.5 inches in length.
2Manufacturing precision
If significant lateral shift is applied to justify small envelopes, then justification is achieved, but envelope skewing increases
Solution Approach 1:
The compliant wall dynamically adjusts its position during the justification process, providing gradual guidance rather than abrupt lateral shifting. This dynamic adjustment maintains envelope stability by reducing sudden movements that cause skewing, while still achieving precise edge justification through controlled, progressive positioning.
3Manufacturing precision
If fixed justification wall position is used, then small envelopes can be justified, but large envelopes require excessive lateral travel
Solution Approach 1:
The justification wall is designed to be compliant and adaptable rather than fixed. This allows the wall to adjust its effective position and angle based on the envelope size, providing accurate justification for large envelopes with minimal lateral travel by accommodating their dimensions through compliant movement rather than requiring extensive lateral displacement.
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 efficient edge justification of variable-sized envelopes at high speeds, maintaining envelope pitch and preventing skewing, allowing for accurate postage placement and handling up to 26,000 mail pieces per hour, while minimizing lateral accelerations and velocities.
Implementation Method 1
a series of steerable nips, which are arranged in line, parallel to the mail flow direction. As the mail piece travels though the justifier, the nips will rotate to impart a lateral velocity to the mail piece
Implementation Method 2
The steerable nips are servo controlled so that they can vary the amount of lateral shift on a per piece basis
Data Source
AI summary
An edge justification device for a mail processing machine. The device shifts the mailpiece from bottom edge justified to top edge justified. The amount of shift is determined as a function of the height of the mail piece. One embodiment solves the problem of switching from bottom to top registration by having a series of steerable nips, which are arranged in line, parallel to the mail flow direction. As the mail piece travels though the justifier, the nips will rotate to impart a lateral velocity to the mail piece, shifting it over to properly justify it. In a further embodiment, the nips of the justification device are not steerable. Rather, a whole nip assembly that is transporting the mail piece is moved laterally to switch from bottom to top justification.