Dual Torque Limiter for Brake Roller Multi-Feed Prevention
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Solution Overview
Problem
In medium conveying apparatuses, multi-feed of media occurs due to high frictional forces, leading to jamming issues, especially when handling thin papers, and existing solutions like increasing brake roller torque are not optimal as they can cause jams or slip.
Innovation Solution
A medium conveying apparatus with a dual torque limiter system, where the first torque limiter sets a lower limit for single media and the second torque limiter sets a higher limit for multiple media, along with a pick arm and stopper mechanism to adjust the torque based on media height, ensuring appropriate friction and preventing jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the maximum torque applied to the brake roller is increased to suppress multi-feed, then multi-feed occurrence is reduced, but medium jamming occurs when thin paper is conveyed
Solution Approach 1:
The patent applies dynamics by making the torque limiter switchable between two different limit values. The torque limiter can dynamically change its torque limit based on the feeding conditions (single sheet vs. multiple sheets), allowing the system to adapt the brake roller torque to the actual medium stack height and friction conditions, thereby preventing both multi-feed and jamming
Solution Approach 2:
The patent changes the torque parameter of the brake roller by providing two different torque limit values (first limit value and second limit value). The control unit selects which torque limit to apply based on detected conditions such as medium stack height or friction characteristics, thereby optimizing the torque parameter for each specific feeding scenario to avoid both multi-feed and jamming
2Device complexity
If a single torque limiter is used for the brake roller, then the structure is simple, but it cannot adapt to different medium conditions (thin paper vs. multiple sheets)
Solution Approach 1:
The patent makes the torque limiter universal by designing it to perform multiple functions through switching between two torque limit values. The same torque limiter mechanism can adapt to different medium conditions (thin paper, thick paper, single sheet, multiple sheets) by changing its limit value, eliminating the need for entirely separate torque limiting mechanisms for different conditions
Solution Approach 2:
The torque limiter is made dynamic and adjustable rather than fixed. The control unit enables switching between a first torque limit value and a second torque limit value based on real-time detection of medium conditions, allowing the torque limiter to adapt its characteristics to match the specific feeding requirements
3Ease of operation
If electromagnetic clutch is used to change rotational load of brake roller, then separation force can be adjusted, but device complexity increases
Solution Approach 1:
The patent replaces complex electromagnetic components with simpler, more reliable mechanical torque limiters. By using mechanical torque limiters with switchable limit values instead of electromagnetic clutches, the system achieves torque adjustment functionality with simpler, more durable components that have fewer failure points and lower cost
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
Effectively prevents multi-feed while minimizing the risk of jamming by dynamically adjusting the torque applied to the brake rollers based on media height, ensuring reliable feeding of various paper types without excessive torque.
Implementation Method 1
a torque limiter to idle a separation roller in a first rotation direction when a rotational torque applied to the separation roller in the first rotation direction exceeds the limit torque which is a predetermined torque upper limit value
Data Source
AI summary
A medium conveying apparatus includes a setting member to set a torque limiter that defines a maximum torque applied to a brake roller to a first torque limiter or a second torque limiter, a unit including the first torque limiter, the second torque limiter and the brake roller, and a transmission member to transmit a drive force to the first torque limiter. The unit is swingably supported so that a predetermined force acts on the brake roller in a direction away from the feed roller when the driving force is transmitted. A force in a direction in which the brake roller presses the feed roller when the second torque limiter defines the maximum torque applied to the brake roller is greater than the force in the direction in which the brake roller presses the feed roller when the first torque limiter defines the maximum torque applied to the brake roller.