Pivoting Hold-Down Device for Cross-Cutting Jams
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Solution Overview
Problem
Existing cross-cutting devices for winding machines face issues with material accumulation between the rotating knife and hold-down device, leading to potential damage when the knife becomes dull, as the hold-down device can be torn off due to forces generated during cutting.
Innovation Solution
The cross-cutting device is designed to pivot partially into the plane of the web during cutting, with a movable hold-down device that shifts to an alternative position in case of material jam, allowing it to avoid forces and prevent damage. The hold-down device is arranged to pivot independently of the knife's rotation, and a spring-loaded latching mechanism adjusts to different material conditions, ensuring safe operation and preventing premature pivoting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hold-down device is fixed in position during cutting, then cutting precision is maintained, but the device is vulnerable to damage when material accumulates between the blade and hold-down device
Solution Approach 1:
The hold-down device is transformed from a fixed structure to a movable one that can pivot between an operating position (for precise cutting) and an escape position (to avoid damage from material accumulation). This dynamic capability allows the device to adapt to varying cutting conditions and protect itself from damage.
Solution Approach 2:
The spring-loaded latching mechanism provides a pre-configured safety feature that automatically engages when excessive force is detected during cutting. This beforehand cushioning prevents damage by allowing the hold-down device to pivot to the escape position before catastrophic failure can occur.
2Reliability
If the hold-down device is made movable to avoid jams, then damage prevention is improved, but cutting precision may be compromised
Solution Approach 1:
The hold-down device utilizes a pivot mechanism that allows it to switch between two distinct positions: an operating position where it maintains precise contact with the material web for accurate cutting, and an escape position where it moves away to avoid damage from material accumulation. The spring-loaded latching mechanism ensures reliable positioning in both states.
3Reliability
If the spring load of the locking device is increased to prevent premature pivoting, then false triggering is reduced, but the device becomes more sensitive to material variations
Solution Approach 1:
The spring-loaded latching mechanism is designed with adjustable spring load parameters that can be optimized for different material types, thicknesses, and strengths. This parameter adjustment capability allows the device to distinguish between normal cutting forces (which should not trigger pivoting) and abnormal forces indicating material jams (which should trigger the escape position).
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 design effectively prevents material accumulation and damage to the cross-cutting device by allowing the hold-down device to move clear of jams, even when the knife is blunt, and includes safety features for manual or automatic operation to prevent operator injury and ensure machine safety.
Implementation Method 1
the flange has a spring-loaded locking device that holds the flange and hold-down device in the operating position
Implementation Method 2
the hold-down device is pivotably mounted around the knife's pivot point. In the event of a material jam, the hold-down device, by pivoting, deflects the forces arising from the movement perpendicular to the material web
Data Source
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AI summary
The present invention relates to a transverse cutting device (10) for a winding machine (1), which extends transversely to the transport direction of a web of material and is designed to pivot at least partially into the plane of the web from a rest position for the cutting process of the web of material, comprising at least one knife (13) which is arranged to be movable along a guide (12) orthogonally to the transport direction of the web of material, with a hold-down device (14) which continuously interacts with the knife (13) during the cutting process, wherein the hold-down device (14) is designed to be moved from an operating position to a fallback position.