Elevator Working Platform Blocking Structure Against Accidental Stowing

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Solution Overview

Problem

Existing elevator maintenance platforms risk being accidentally returned to the stowed position before maintenance tasks are completed, potentially causing damage to components due to insufficient overhead clearance.

Innovation Solution

A blocking member is integrated into the elevator car's support frame to prevent the working platform from being moved into the stowed position until all maintenance tasks are finished, ensuring components are restored to their operational state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the working platform is made foldable to reduce overhead distance, then the overhead clearance is reduced, but the risk of accidental stowing before maintenance completion increases

Engineering Contradiction:
Improveoverhead distanceVSAvoidsafety of maintenance person
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The blocking member is positioned to prevent the working platform from being stowed before maintenance is complete. It creates a preliminary counter-action that blocks the stowing motion, forcing the maintenance person to complete tasks before the platform can be folded away, thus preventing accidental stowing

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The blocking member is pre-positioned in the hoistway to intercept the working platform before it can be accidentally stowed. This preliminary positioning ensures that even if the maintenance person forgets to keep the platform deployed, the blocking member will physically prevent the stowing action from completing

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the blocking member is added to prevent accidental stowing, then the safety is improved, but the device complexity increases

Engineering Contradiction:
Improvesafety of maintenance personVSAvoidstructure of elevator car
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blocking member is divided into separate functional segments: a blocking portion that physically prevents platform stowing, and an unblocking portion that can be manually moved to release the block. This segmentation allows the safety function to be added as a discrete component rather than integrating complexity into the existing platform mechanism

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blocking member acts as an intermediary element between the hoistway structure and the working platform. Rather than modifying the platform itself or the hoistway, it introduces a separate mediating component that temporarily intervenes to prevent accidental stowing, keeping the modification minimal and localized

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the blocking member is manually unblocked after maintenance, then the safety check is ensured, but the loss of time occurs

Engineering Contradiction:
Improvecompletion of maintenance tasksVSAvoidtime to stow platform
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The blocking member system is designed to be self-regulating through its mechanical configuration. The blocking portion automatically engages to prevent stowing, and the unblocking portion can be easily moved by the maintenance person as a simple manual action. The system serves itself by using the maintenance person's own actions (moving the unblocking portion) to control the blocking function, requiring minimal additional time or external intervention

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4286314B1Elevator car with blocking member for foldable working platform
Publication Date: 2026.03.25 OTIS ELEVATOR CO
  • EP4286314B1 patent drawingFigure 1a~1c
  • EP4286314B1 patent drawingFigure 2a~2b
  • EP4286314B1 patent drawingFigure 3

AI summary

An elevator car has one or more sidewalls (4a, 4b) defining an interior space (2) for accommodating passengers; a roof (3) including a support frame (8) and a working platform (12) which is suspendably connected to the support frame (8). The working platform moves between a stowed position, above the interior space, and an operational position, within the interior space. The elevator car also includes a blocking member (20, 21), located at the support frame (8), and arranged to move between an unblocking position and a blocking position. When the blocking member (20, 21) is in the blocking position, the blocking member is configured to prevent the working platform (12) from being moved into the stowed position.