Sheet Feeding Device with Pendulum Rollers and Independent Drives
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Solution Overview
Problem
Existing sheet feeding devices suffer from inaccuracies in sheet transport due to the negative effect of suction belt elasticity changes over time, leading to fluctuations in sheet distance and delayed or premature sheet arrival at the end of the transport path.
Innovation Solution
The device employs a conveyor belt system with a unique configuration of belt rollers, including a larger diameter drive-associated roller and pendulum rollers, which maintain tension and correct belt errors, combined with independent drives for each component, ensuring precise sheet transport and adaptation to format changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If suction belts are used to transport sheets, then sheets can be conveyed, but the elasticity of the suction belt changes over time causing negative effects on conveying accuracy
Solution Approach 1:
The suction belt is divided into multiple individual suction belts (first suction belt, second suction belt, etc.) that can be independently controlled. This segmentation allows each belt to be optimized for specific functions and reduces the impact of elasticity changes in one belt on the overall system accuracy.
Solution Approach 2:
The patent implements dynamic speed control where each suction belt can operate at different speeds according to a non-uniform speed profile. The control device adjusts the speed of individual suction belts based on real-time requirements, compensating for elasticity changes and maintaining conveying accuracy throughout the service life of the belts.
2Manufacturing precision
If individual drives are assigned to each suction belt, then precise control is achieved, but device complexity increases
Solution Approach 1:
The control device serves multiple functions: it controls the timing of sheet separation, regulates the speed of each suction belt individually, and coordinates the overall sheet feeding process. This multi-functionality reduces the need for separate control systems for each component, managing device complexity while maintaining precision.
Solution Approach 2:
The system incorporates a control device that monitors and adjusts the speed of each suction belt based on the timing and position of sheets. This feedback mechanism ensures precise sheet transport by continuously optimizing the operation of individual drives, achieving high manufacturing precision without requiring overly complex hardware configurations.
3Measurement precision
If non-uniform speed profile is used for suction belts, then sheet arrival timing is improved, but control complexity increases
Solution Approach 1:
The control device is configured to pre-program non-uniform speed profiles for each suction belt before sheet transport begins. By establishing these speed variations in advance based on predicted sheet timing requirements, the system achieves precise sheet arrival timing without requiring complex real-time calculations during operation.
Solution Approach 2:
The suction belts operate with periodic speed variations that correspond to the rhythmic nature of sheet feeding. The non-uniform speed profile is applied in regular cycles synchronized with the sheet separation and transport process, simplifying control complexity by using repetitive patterns rather than arbitrary speed changes.
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 configuration reduces sheet distance fluctuations and ensures exact timing of sheet arrival, minimizing the impact of suction belt elasticity changes and improving overall transport accuracy and uniformity.
Implementation Method 1
a first suction belt (14.1) for transporting the sheets from the stack to the belt table
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a device for feeding sheets to a sheet-processing machine comprising at least one processing unit, the device having: a sheet separator (7) for separating the sheets from a stack in cycles and comprising transport suckers for transporting the sheets to a belt table (2), the belt table (2) having at least one circulating conveyor belt (14), which is guided via at least two belt rolls (12.1, 12.2, 12.3, 12.4, 12.5), at least one belt roll (12.1, 12.2, 12.3, 12.4, 12.5) being associated with a first drive (25), and a sheet flap connected to a pivotably mounted shaft being provided between the transport suckers and the at least one conveyor belt (14), the shaft being associated with a second drive (24) which pivots said sheet flap; a sheet arrival sensor, which is arranged between the belt table (2) and the processing unit and, for a sequence of sheets, generates first signals representing the arrival of the sheets; a clock generator, which generates second signals representing the angular position of the at least one processing unit; and a controller, which controls the first drive (25) depending on the second signals and controls the second drive (24) depending on the first and second signals.