Sheet Feeder Skip Feed Cam for Emergency Stop
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Solution Overview
Problem
Existing sheet feeder systems in carton-forming machines face challenges in performing emergency stops and high-speed skip-feeds due to limitations in the main drive system and air cylinder extensions, which fail to meet the high-speed requirements of modern manufacturing lines.
Innovation Solution
A sheet feeder system incorporating a link mechanism, a spring, a grate raising/lowering cam, a skip feed cam, and an electric motor, along with control means and phase detection mechanisms, allows for independent operation of the skip feed cam during emergency stops and high-speed skip-feeds, ensuring reliable paper supply and emergency stop functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the main drive system is used to control the grate raising and lowering operations, then the paper supply is synchronized with the printing cylinder rotation, but the system cannot perform emergency stops or high-speed skip-feeds when the main drive system fails
Solution Approach 1:
The patent segments the drive system into two independent parts: the main drive system for normal operation and a separate auxiliary drive system (motor M2) for emergency operations. The auxiliary drive system can independently control the grate raising and lowering operations without relying on the main drive system, enabling emergency stops and high-speed skip-feeds while maintaining paper supply reliability.
Solution Approach 2:
The patent changes the operational parameters of the grate by introducing a separate auxiliary drive system that can operate at different speeds and modes compared to the main drive system. This allows the system to perform high-speed skip-feeds and emergency stops with different timing characteristics than normal synchronized operation.
2Speed
If air cylinders are used to raise the grate for skip-feed operations, then the grate can be raised independently, but the extension and contraction speeds and air supply delays prevent high-speed operations
Solution Approach 1:
The patent replaces the pneumatic system (air cylinders) with a direct mechanical drive system (motor M2 connected to cam C2). This mechanical substitution eliminates air supply delays and enables faster grate raising and lowering speeds, allowing high-speed skip-feed operations to be performed without the limitations of pneumatic response times.
3Adaptability or versatility
If a single-mode cam is used to raise the grate once per machine period, then the paper supply is synchronized with the main drive, but skip-feed operations require additional multiple-mode cams and complex control
Solution Approach 1:
The auxiliary drive system with motor M2 and cam C2 is designed to be multi-functional: it can perform normal skip-feed operations, high-speed skip-feeds, and emergency stops using the same hardware components. The control unit simply changes the operational mode and timing parameters rather than requiring different physical cams for different functions, reducing overall system complexity.
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
The system enables efficient normal and skip-feed operations, maintaining high-speed performance and reliability by controlling the skip feed cam independently of the main drive system, effectively addressing the limitations of previous technologies.
Implementation Method 1
a spring (120) which engages with any link of the link mechanism and urges the grate to the lowered position
Implementation Method 2
a grate raising/lowering cam (130) which has a cam surface which can abut on any link of the link mechanism and periodically raises and lowers the grate
Data Source
AI summary
A sheet feeder includes: a wheel for issuing a lowermost sheet out to a sheet processing unit; a grate for spacing the sheet apart from the wheel at a raised position and bringing the sheet into contact with the wheel at a lowered position; and a drive device for driving the grate up and down. The drive device includes: a link mechanism for movably supporting the grate; a spring for urging the grate to the lowered position; a grate raising/lowering cam for periodically driving the grate up/down; and a skip feed cam that is driven by a control device, separately from a drive system of the grate raising/lowering cam, and that, at a timing where reached is a phase at which the grate raising/lowering cam does not put the grate in the raised position, retains the grate at the raised position in order to skip feeding of the sheet.