Knife Folding Device Servo-Driven Stroke Adjustment

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Solution Overview

Problem

Conventional knife folding machines lack the ability to separately adjust the positions of the knife blade's reciprocal movement, leading to inefficient high-speed folding operations and durability issues due to offset loads, and fail to detect overload conditions, resulting in paper jams.

Innovation Solution

A knife folding machine with a knife drive unit comprising a rod, feed screw, and servomotor that allows for adjustable stroke and position control of the knife blade, along with a sensor system to detect overload and prevent paper jams by stopping the knife blade during multiple sheet bundle feeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the second position of the knife blade is adjusted by changing the position of the upper dead point of the slider crank mechanism, then the knife blade can reach different positions, but the first and second positions cannot be separately changed and the stroke remains constant

Engineering Contradiction:
Improveadjustability of knife blade positionsVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention divides the knife blade position control into two independent parameters: the upper dead point position (first position) and the lower dead point position (second position). By segmenting the position adjustment mechanism, the patent enables separate control of both positions while maintaining a relatively simple overall structure through the slider crank mechanism with adjustable links.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic adjustability to the knife blade positions by making the upper dead point and lower dead point independently variable. This allows the first and second positions to be separately changed according to different sheet bundle thicknesses, providing adaptability without requiring a completely complex mechanism.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the stroke of the knife blade is made constant in the slider crank mechanism, then the mechanism is simple, but the folding operation cannot be optimized for different sheet bundle types

Engineering Contradiction:
Improvefolding operation efficiencyVSAvoidmechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent makes the stroke of the knife blade variable by independently adjusting the upper and lower dead point positions. This allows the stroke length to be optimized for different sheet bundle types, improving folding efficiency while maintaining a relatively simple slider crank mechanism structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameters of the slider crank mechanism, specifically the lengths of the links connecting the crank to the knife blade. By varying these parameters, the stroke of the knife blade can be adjusted to match different sheet bundle thicknesses, optimizing the folding operation for each type.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the rod is constantly subjected to offset load in the slider crank mechanism, then the reciprocal movement is achieved, but the durability of the knife folding machine deteriorates

Engineering Contradiction:
Improvereciprocal movement capabilityVSAvoidmachine durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a counterweight mechanism to balance the offset loads acting on the rod during reciprocal movement. By adding a counterweight, the harmful offset forces are counteracted, reducing wear and stress on the rod and other components, thereby improving machine durability while maintaining the reciprocal movement capability.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The invention converts the harmful offset load into a beneficial balancing force by introducing a counterweight. The offset load that previously caused deterioration is transformed into a useful counterbalancing effect, reducing overall stress on the mechanism and improving reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Productivity

If the knife blade continues to move during overload conditions, then the folding operation completes, but paper jam occurs between the folding rollers

Engineering Contradiction:
Improvefolding operation continuityVSAvoidpaper jam prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism that monitors the folding operation in real-time. When overload conditions are detected (such as multiple sheet bundles fed at once), the system provides feedback to stop the knife blade movement, preventing paper jam while allowing normal folding operations to continue.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention replaces pure mechanical operation with a controlled system that incorporates sensing and control. By substituting automatic mechanical continuation with a controlled stop mechanism, the system prevents paper jam while maintaining productivity through selective operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables adjustable folding operations for varying sheet bundles, improves machine durability by eliminating offset loads, and prevents paper jams by detecting and responding to overload conditions during folding.

Implementation Method 1

a feed screw extending in parallel to the rod and attached to the holder to rotate around an axis thereof, the block having a thorough hole which has thread grooves corresponding to the feed screw, the feed screw engaging with the through hole, the rod being reciprocated by the rotation of the feed screw

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a servomotor attached to the holder and having a drive shaft, the drive shaft extending in parallel to the feed screw

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP2511212B1Knife folding device
Publication Date: 2016.03.30 HORIZON INTERNATIONAL INC
  • EP2511212B1 patent drawingFigure 1
  • EP2511212B1 patent drawingFigure 2
  • EP2511212B1 patent drawingFigure 3

AI summary

In the knife folding machine of the present invention it is possible to easily adjust the stroke of the reciprocal movement of the knife blade 5. The rod 10 is reciprocated by the feed screw 12. The feed screw 12 is rotated by the servomotor 14. Thus when the knife blade 5 reciprocates between the first and second positions, the first and second positions thereof are separately adjusted by controlling the amount of the rotation of the servomotor 14.