Sheet Feeder Dual Discharge Registration
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Solution Overview
Problem
Existing sheet feeders, such as the Longford OS700 surge feeder, are unable to handle products with features like tails or tabs due to the mechanism of lugged chains that push sheets from the trailing edge, leading to misalignment and potential damage, and struggle with achieving precise registration and alignment on a moving web.
Innovation Solution
A two-stage discharge conveyor system using feeder stripper wheels and motor-driven belts, with separately driven lugged timing belts that engage sheets before they leave the conveyor, ensuring precise alignment and spacing without pushing against the trailing edge, and maintaining a speed ratio between transport and lugged belts to achieve uniform spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lugged chains push sheets from the trailing edge, then sheets are registered and aligned on the discharge conveyor, but products with tails or tabs cannot be handled and sheets may be damaged
Solution Approach 1:
Instead of pushing sheets from the trailing edge, the lugs engage the leading edge of the sheets. This inversion of the engagement point allows sheets to be registered and aligned without pushing against tails or tabs, resolving the contradiction between achieving precise registration and handling diverse product types.
Solution Approach 2:
The lugs on the lugged chains engage the leading edge of sheets in advance, before the sheets reach the discharge point. This preliminary engagement ensures proper registration and alignment is established early in the transport process, allowing subsequent handling without damage to sheets or interference with product features.
2Manufacturing precision
If lugs are positioned to engage sheets at the discharge point, then registration is achieved, but sheets may be struck and damaged as they leave the conveyor
Solution Approach 1:
The lugs engage and register sheets at an earlier position along the conveyor path, completing the alignment action before sheets reach the discharge point. This preliminary registration ensures sheets are properly positioned without requiring lug engagement at the critical discharge location, eliminating the risk of sheet damage.
Solution Approach 2:
The conveyor system is divided into distinct functional zones: a registration zone where lugs engage and align sheets, and a discharge zone where sheets are released without lug interference. This segmentation allows registration to be completed in advance, separating the alignment function from the discharge function to prevent sheet damage.
3Object-affected harmful factors
If a complex hinging mechanism is used to drop lugs in unison, then sheet damage is avoided, but device complexity and cost increase
Solution Approach 1:
Sheet registration and alignment are completed in advance by lugs engaging the leading edge, before sheets reach the discharge point. This eliminates the need for complex hinging mechanisms that would be required to coordinate lug movement at the discharge location, simplifying the overall device while still preventing sheet damage.
Solution Approach 2:
The complex hinging mechanism is removed entirely from the system. Instead of using articulated lugs that can drop in unison, the invention uses fixed lugs on the lugged chains that engage sheets earlier in the transport path, extracting the unnecessary complexity while maintaining sheet protection.
4Manufacturing precision
If lugs push sheets at the discharge point, then alignment is achieved, but throughput is limited
Solution Approach 1:
Sheet registration and alignment are performed in advance during the transport phase, allowing sheets to be properly positioned before reaching the discharge point. This preliminary alignment does not interfere with the discharge timing, enabling higher throughput rates while maintaining precise registration.
Solution Approach 2:
By engaging sheets at the leading edge rather than pushing from the trailing edge at discharge, the system allows simultaneous registration and high-speed transport. The inversion of engagement timing and location eliminates the bottleneck that limited throughput in previous designs.
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
This design allows for precise registration and alignment of sheets, enabling the handling of products with features that existing systems cannot manage, and effectively doubles the minimal throughput of the Longford OS700 Surge Feeder.
Implementation Method 1
The second stage discharge conveyor includes an upper and a lower set of endless transport belts that frictionally engage sheets between a lower belt flight of the upper set and an upper belt flight of the lower set
Implementation Method 2
an appropriate ratio is maintained between the speed at which the sheet transport belts are driven and the speed at which the lugged belts are driven and whereby the transport belts move at a slightly greater speed than the lugged belts
Data Source
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AI summary
A sheet feeder feeds product, one at a time, from the bottom of a stack onto a second stage discharge conveyor in which the serialized products are brought into precise registration prior to being deposited onto a moving web. To achieve registration, the products are transported at a higher rate than the speed of a pair of timing belts having regularly spaced lugs projecting therefrom. The lug timing belts are positioned beneath the belts transporting the product with the lugs projecting into the product's path of travel. The speed deference is that a leading edge of the products is brought into engagement with the trailing edge of a laterally aligned pair of lugs before the product arrives at the discharge point of the second stage discharge conveyor. The transport rate on the second stage discharge conveyor is controlled to match the speed of the moving web.