Escalator Step Belt Locking Device for Maintenance Safety
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Solution Overview
Problem
Maintenance of escalators and moving walks poses risks due to the potential unintended movement of step or pallet belts during servicing, which can lead to accidents when parts are removed or replaced, as existing braking systems can decouple and cause the belts to rotate unintentionally.
Innovation Solution
A blocking device with pivotable blocking arms that can be locked in either a release or engagement position, engaging with the transport chain to prevent movement and ensuring the drive motor is powered off when maintenance is performed, thereby enhancing safety by directly intervening in the transport chain's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a braking device acts on the drive train or drive motor to stop the step or pallet belt, then the belt can be decelerated to a standstill, but the braking device can decouple and cause the belt to rotate unintentionally during maintenance
Solution Approach 1:
The braking system is segmented into two independent functional components: a braking device that acts on the drive train to decelerate the belt, and a separate blocking device with blocking arms that directly engage the transport chain to prevent unintended rotation. This segmentation ensures that the blocking device provides independent safety functionality not dependent on the braking device's state.
Solution Approach 2:
The blocking arms serve as intermediary elements that directly engage with the transport chain links. These blocking arms physically intervene in the chain's movement by engaging with intermediate link spaces, providing a mechanical barrier that prevents unintended rotation during maintenance operations.
2Reliability
If the blocking arm engages in the transport chain to prevent movement, then safety during maintenance is improved, but the device complexity increases due to additional blocking arms and switching elements
Solution Approach 1:
The blocking device integrates multiple functions into a unified structure: the blocking arms both physically block the transport chain from moving and simultaneously activate switching elements that control power supply to the drive motor. This multi-functionality reduces the need for separate safety interlocks and control mechanisms.
Solution Approach 2:
The switching elements are merged with the blocking arm structure itself. When the blocking arm engages with the transport chain, the same mechanical movement activates the switching element to interrupt power supply. This merging eliminates the need for separate sensors or interlock mechanisms, simplifying the overall device complexity.
3Reliability
If multiple blocking arms are used to secure both transport chains, then safety is improved, but the device complexity and number of components increase
Solution Approach 1:
The blocking arms are designed to be pivotable between an engaged position (where they block the transport chain) and a retracted position (where they clear the chain). This dynamic capability allows a single blocking device structure to serve multiple chains sequentially or simultaneously, reducing the need for permanently installed blocking elements on each chain.
Solution Approach 2:
The blocking device is positioned and configured in advance to be able to engage with intermediate link spaces of the transport chain. The switching elements are pre-positioned to be activated by the blocking arm's engagement movement, ensuring that safety functions are automatically implemented before maintenance work begins.
Data Source
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AI summary
The invention relates to a moving staircase (1) having a step belt (13) or a moving walkway (1) having a pallet belt (13), which step or pallet belt (13) comprises at least one transport chain (10, 10A, 10B) that is arranged in a revolving manner between a first and a second return region (2, 3) of the moving staircase (1) or moving walkway (1). Steps (9) or pallets (9) are arranged on the transport chain (10, 10A, 10B) and connected to the transport chain (10, 10A, 10B). Further, at least one locking device (7, 7A, 7B, 47), which has at least one locking arm (8, 8A, 8B, 48A, 48B), is arranged in a stationary manner. The locking arm (8, 8A, 8B, 48A, 48B) can be brought into a release position or into an engagement position, wherein said locking arm (8, 8A, 8B, 48A, 48B) engages in at least one link interspace in the transport chain (10, 10A, 10B) when in the engagement position, and the locking arm (8, 8A, 8B, 48A, 48B) can be fixed in the respective release position or engagement position.