Height Adjustable Platform Emergency Lowering via Secondary Cable
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Solution Overview
Problem
Existing manually adjustable height platforms face safety concerns due to difficulties in lowering the platform in emergency situations, potential for uncontrolled elevation, and insufficient height, along with risks of operator injury from climbing and platform instability.
Innovation Solution
A manually operable height adjustable platform with a scissor mechanism, gas struts, and an actuation system that allows controlled extension and retraction, featuring a manual actuator for normal operation and an override mechanism for emergency lowering, along with a railing arrangement that discourages climbing and provides safe access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual crank handle is used to operate the pulley mechanism for platform elevation, then the platform can be raised and lowered manually, but in emergency situations it becomes difficult or impossible for ground personnel to lower the platform when the operator is incapacitated
Solution Approach 1:
A secondary cable mechanism acts as an intermediary between ground personnel and the platform lowering function. The secondary cable runs from ground level through a pulley system to connect with the primary drive belt, allowing ground personnel to pull the secondary cable and thereby tension the primary belt to lower the platform without needing to access the crank handle directly.
Solution Approach 2:
The control interface is moved from a vertical dimension (crank handle at platform height) to a horizontal dimension (secondary cable accessible at ground level). This dimensional shift allows emergency lowering to be performed from ground level rather than requiring access to the elevated platform position.
2Object-affected harmful factors
If the platform is lowered partially to remove an incapacitated operator, then the operator can be rescued, but the reduced weight causes the platform to rise again under gas spring bias
Solution Approach 1:
The secondary cable mechanism maintains continuous control over the platform position during the entire rescue operation. As the operator is pulled down, the secondary cable remains taut and allows ground personnel to continuously apply force to prevent the platform from rising, ensuring continuous control rather than intermittent adjustment.
Solution Approach 2:
The secondary cable system provides a pre-prepared control mechanism that counteracts the gas spring bias force before the platform can rise uncontrollably. The cable is positioned and tensioned in advance to compensate for the upward force that will occur when operator weight is reduced.
3Ease of operation
If the drive belt is made flexible to allow pulley mechanism operation, then the mechanism can function smoothly, but the belt becomes prone to jamming, wear, and fraying
Solution Approach 1:
The drive belt system incorporates dynamic tensioning through the gas spring mechanism. The gas spring maintains optimal tension on the belt during operation, allowing smooth power transmission while compensating for belt stretch and wear over time. The tension is automatically adjusted as the belt condition changes.
Solution Approach 2:
The system includes backup mechanical linkages and guide wheels positioned to prevent belt misalignment before it causes failure. The belt path is pre-configured with alignment guides and tension maintainers that cushion against conditions that would lead to jamming or fraying.
4Length of moving object
If the platform height is increased to provide adequate working height, then the platform reaches necessary elevation levels, but the maximum height is limited to less than double the mast height when lowered
Solution Approach 1:
The mast structure employs a nested telescopic design where inner mast sections slide within outer mast sections. This nesting allows the mast to extend to more than double its lowered height while maintaining a compact profile when retracted. Multiple nested stages provide extended reach without proportionally increasing the base structure size.
Solution Approach 2:
The mast system incorporates dynamic extension capabilities through the pulley and cable mechanism that can extend the mast beyond its static folded length. The system allows the mast to achieve variable lengths depending on operational requirements, providing adaptability in height adjustment range.
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
Enhances safety by enabling controlled platform movement, preventing uncontrolled elevation, and providing adequate height adjustment while reducing the risk of operator injury through secure access and stability features.
Implementation Method 1
The housings are moveable relative to each other by a pulley mechanism, i.e. a drive loop, operated by an external crank handle on the elevatable platform 26. The mast 16 comprises nested inner and outer housings 20,22, biased apart, i.e. to an extended condition, via a gas spring 30.
Implementation Method 2
The pulley mechanism 24 comprises fixed pulley wheels 34,36 located on an inner face of outer housing 22, and a toothed a drive belt 38 passes around wheels 34, 36 and is fed between drive cog 40 and guide wheel 41 pivotally located on housing 22.
Implementation Method 3
The crank handle 26 is operatively connected to the drive cog 40, and during rotation of the handle 26, the belt 34 is driven over the cog 40. This allows the gas spring to extend, i.e. using the handle 26 to selectively release the gas spring in a controlled manner, thereby driving the outer housing 22 relative to the inner housing 20 and raising the platform 18.
Data Source
AI summary
A manually operable height adjustable platform has a platform mounted to a base via an extensible scissor mechanism. At least one drive strut is mounted in a force path between the platform and the base and configured to bias the platform and the base away from one another via extension of the scissor mechanism. An actuation system controls movement of the platform and the base away from one another under the biasing force, where the actuation system has a manual actuator operatively connected to a pinion on one of the platform and scissor mechanism/base configured to engage a rack on the other of the platform and scissor mechanism/base. A manual actuator mounted above the platform operates the actuation system by an operator in normal use, and an override mechanism mounted below the platform acts on the drive strut for lowering of the platform without actuation of the manual actuator.