Strapping Band Tensioning Wheel Release With Wrap Spring Freewheel
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Solution Overview
Problem
Existing strapping apparatuses face issues with the abrupt release of tensioned strapping bands, leading to high dynamic loads on the fastening and tensioning device, which can cause damage and wear, particularly in mobile applications.
Innovation Solution
Incorporation of a freewheel mechanism with a wrap spring that allows for a gradual release of the tensioning wheel from the strapping band by enabling slippage and a non-abrupt disengagement from the drive, using a wrap spring to support the tensioning wheel on a fixed component, and a toothing mechanism for controlled actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a freewheel mechanism with wrap spring is used to release the tensioning wheel from the strapping band, then the release process becomes gradual and non-abrupt, but the device complexity increases
Solution Approach 1:
A wrap spring is introduced as an intermediary element between the tensioning wheel and the fixed component. The wrap spring enables gradual release by allowing controlled slippage through friction, transforming the abrupt release into a progressive disengagement process that reduces dynamic loads on the fastening and tensioning device
Solution Approach 2:
The frictional engagement between the wrap spring and contact partners creates a dynamic release mechanism. The wrap spring can transition from a frictionally engaged state (during tensioning) to a slipped state (during release), allowing the system to adapt its mechanical coupling characteristics based on operational phase, thereby preventing abrupt load changes
2Productivity
If the tensioning device releases the band abruptly, then the release process is quick and simple, but high dynamic loads are generated that can damage the fastening and tensioning device
Solution Approach 1:
The wrap spring acts as a cushioning element that is pre-positioned between the tensioning wheel and the fixed component. During release, the wrap spring absorbs and dissipates the stored elastic energy gradually through controlled slippage, preventing the sudden transmission of high dynamic loads to the fastening and tensioning device
3Force
If the tensile stress of the band acts on the tensioning wheel and tensioning plate, then the band can be tensioned effectively, but jamming of the rocker can occur preventing the tensioning wheel and tensioning plate from being lifted off
Solution Approach 1:
The wrap spring serves as a mediator that decouples the tensioning wheel from the fixed component during the release phase. By allowing the wrap spring to slip and disengage from its contact partners, the high tensile stress is gradually released without being transmitted to the rocker mechanism, preventing jamming and enabling smooth operation
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 freewheel mechanism reduces wear and damage to the tensioning device by allowing a gentle release of the strapping band, maintaining functional reliability and preventing jamming, thus extending the lifespan of the apparatus.
Implementation Method 1
a wrap spring (33) which, during an actuation, with at least initial slippage, eliminates a frictionally engaging connection to at least one contact partner (35, 36) of the strapping apparatus (1)
Implementation Method 2
a wrap spring (33) which, during an actuation, with at least initial slippage, eliminates a frictionally engaging connection
Data Source
AI summary
A strapping apparatus for strapping articles with a strapping band having a tensioning device for imparting a band tension to a loop of the strapping band, the tensioning device including a driveable tensioning element provided for engaging the strapping band to impart a band tension. The strapping apparatus including a connecting device for generating a permanent connection, in particular a welded connection, at two regions, situated one above the other, of the loop of the strapping band. The strapping apparatus is configured to achieve the release of the tensioning element from the strapping band reliably to avoid or reduce adverse characteristics attributed to the release of the tensioning device from the band.