Cam-Actuated Detector Lever for Double Sheet Detection

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Solution Overview

Problem

Existing sheet element processing machines face challenges in reliably detecting superimposed sheets, which can lead to jamming and inefficiencies due to electrostatic forces causing multiple sheets to be delivered together, despite efforts to ensure single-sheet delivery.

Innovation Solution

A detection system utilizing a cam and cam follower lever with a detector lever that can move between a sheet receiving position and a detection position, equipped with a sheet sensing end and a position detector, allows for reliable thickness measurement and indication of abnormal sheet presence, featuring a raising lever for mechanical simplicity and space-saving design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a detection system is added to detect double sheets, then the reliability of sheet detection is improved, but the device complexity increases

Engineering Contradiction:

Improvesheet detection reliabilityVSAvoiddetection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A detector lever is introduced as an intermediary mechanical element that transfers the detection function from a complex sensor system to a simple mechanical indicator. The lever pivots between a first position (indicating single sheet) and a second position (indicating double sheet), providing reliable detection through mechanical means rather than electronic sensors.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The detection system utilizes the existing sheet feeding mechanism and cam-follower lever to automatically position and actuate the detector lever. The system serves itself by using the natural movement of sheets and existing mechanical components to perform the detection function without requiring external power sources or complex control systems.

Inventive Principle:

Principle #25Self-service

2Ease of manufacture

If a raising lever is added to simplify the detection system, then the ease of manufacture is improved, but the device complexity increases

Engineering Contradiction:

Improvedetection system manufacturingVSAvoidmechanical system complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The raising lever is merged with the existing cam-follower lever that controls the sheet feeding mechanism. By combining these functions into a single mechanical component, the system achieves ease of manufacture through standard cam-follower mechanisms while avoiding the need for separate actuation systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cam-follower lever serves multiple functions: it controls the sheet feeding mechanism and simultaneously acts as the raising lever for the detector lever. This multi-functionality reduces the number of separate components needed, simplifying manufacturing while maintaining system functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Volume of moving object

If the detector lever is positioned close to the sheet element, then the space efficiency is improved, but the difficulty of detecting and measuring increases

Engineering Contradiction:

Improvedetection system spaceVSAvoidsheet thickness measurement

Core Design Contradiction:

Volume of moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces electronic thickness sensors with a mechanical detection system. The detector lever's pivot position changes in response to sheet thickness variations, converting a measurement problem into a positional indication problem that can be detected mechanically rather than electronically.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of measuring sheet thickness directly with a sensor, the system inverts the approach by allowing the sheet to move the detector lever to different positions. The detection is achieved by observing which position the lever assumes (first position for single sheet, second position for double sheet) rather than measuring a physical quantity directly.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP3464141B1Detection system for detecting double sheets in a sheet element processing machine, and sheet element processing machine

Publication Date: 2020.05.06 BOBST MEX SA

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AI summary

The invention relates to a detection system for detecting double sheets being supplied to a lateral positioning device (100) for a sheet element (20, 20') in a sheet element processing machine, the sheet element processing machine having a drive system including a cam disk (174) and a cam follower lever (172), the detection system comprising a detector lever (130) mounted so as to be displaceable between a sheet receiving position and a detection position, the detector lever (130) having a sheet sensing end (132) for engagement with an upper face of the sheet element (20, 20') when being in the detection position, and a position detector end (133) for cooperating, when being in the detection position, with a position detector (140) adapted for generating a signal dependent on the thickness of the sheet element (20, 20'), and further comprising a raising lever (170) adapted for raising the sheet sensing end (132) of the detector lever (130), the raising lever (170) being mounted on the cam follower lever (172) of the sheet element processing machine. The invention further relates to a sheet element processing machine comprising a detection system as outlined above, mounted in an introduction station (10) upstream of a processing station.