Smoothing Bar for Sheet Feed Table Crease Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thin sheets tend to warp or form waves at their front edges during transport in sheet-processing machines, leading to tension or creases when gripped by downstream systems, which existing solutions fail to address without damaging the sheet.
Innovation Solution
A smoothing bar with a characteristic curve-controlled drive, connected via a four-bar linkage, moves from the center to the sides of the sheet to smooth it evenly, preventing creases, and is synchronized with the sheet-processing machine to ensure reliable processing without markings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If clamping rollers are used to press the sheet against the feed table, then the sheet is held down during transport, but the sheet surface is damaged with marks and creases
Solution Approach 1:
A smoothing bar is introduced as an intermediary element between the sheet and the feed table. The smoothing bar presses the sheet against the feed table during transport, preventing warping and waves, while its smooth surface prevents direct contact damage to the sheet. The bar acts as a mediator that provides the necessary holding force without causing surface marks or creases.
Solution Approach 2:
The patent replaces the traditional clamping roller mechanical system with a smoothing bar system. Instead of using rotating rollers that can create friction marks and creases, a simple smooth bar is used that can be lowered onto the sheet. This substitution eliminates the harmful mechanical interaction while maintaining the sheet-stabilizing function through a gentler pressing action.
2Object-affected harmful factors
If a smoothing bar is used to flatten the sheet, then the sheet surface is protected from damage, but the sheet may still form creases at the edges
Solution Approach 1:
The smoothing bar is made dynamically adjustable in position and movement. It can be lowered onto the sheet at specific moments during transport and raised when not needed. The bar can move along the sheet length to address different sections, and its pressure can be adjusted to match sheet grammage variations. This dynamic behavior allows the system to prevent edge warping while maintaining surface protection.
Solution Approach 2:
The system changes parameters such as the smoothing bar's position, pressure force, and contact duration to adapt to different sheet conditions. By adjusting these parameters, the system can effectively smooth edge warps without applying excessive force that would cause creases, and can adapt to various sheet grammages and thicknesses.
3Speed
If traditional hold-down devices are used, then sheet transport is controlled, but tension and creases form at the front edge
Solution Approach 1:
The smoothing bar is positioned to act on the sheet before downstream gripper systems engage. By pre-smoothing the sheet surface and stabilizing the front edge during the critical transport phase, the system prevents the formation of warps and waves that would otherwise lead to tension and creases when grippers grasp the sheet. This preliminary action eliminates the root cause of subsequent edge damage.
Data Source
Figure 1
Figure 2~3
Figure 4a~4c
AI summary
In a method and device for holding a sheet down on the feed table of a sheet processing machine, a lowerable smoothing beam (24) is provided which can be driven according to a speed profile in sync with the sheet processing machine, so that a controlled deflection of the smoothing beam results, which is protected so that the sheet is smoothed from the center to the side.