Elevator Car Floor Hatch Assembly for Low-Pit Hoistway Access

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Solution Overview

Problem

Existing elevator systems pose safety risks when maintenance or inspection requires access to the hoistway below the elevator car, particularly in low pits, as there is a risk of the person being hit or squeezed by the elevator car during movement.

Innovation Solution

An elevator car with a movable floor hatch assembly that opens to create a safety volume, allowing access to the hoistway from inside the car, equipped with safety mechanisms to prevent accidental closure and ensure compliance with safety codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a person enters the hoistway below the elevator car for maintenance or inspection, then access to the space is achieved, but safety risk increases due to potential impact or squeezing by the moving elevator car

Engineering Contradiction:
ImproveAccess to hoistwayVSAvoidSafety risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The floor hatch assembly serves as an intermediary structure that mediates between the elevator car interior and the hoistway space. It provides a controlled interface with safety interlocks, allowing access only when the car is properly positioned and the hatch is fully open, thereby eliminating direct uncontrolled exposure to moving parts

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary actions by requiring the elevator car to be positioned at a specific landing before the floor hatch can be opened. Safety interlocks verify proper positioning and hatch status before allowing access, ensuring that the space below the car is safe for maintenance personnel

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the floor hatch assembly is opened to provide access to the hoistway, then safety volume is created for the person below the elevator car, but the structural integrity of the elevator car floor is compromised

Engineering Contradiction:
ImproveSafety volumeVSAvoidFloor structural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The floor hatch assembly is segmented into movable panels that can be opened to create access while maintaining the overall structural framework of the floor. The segmentation allows the floor to remain intact when closed while providing controlled access when open

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The floor hatch assembly transitions from a static closed structure to a dynamic open configuration. The movable design allows the floor to adapt between providing full structural support when closed and creating safety volume when open, with safety interlocks ensuring proper state transitions

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If manual unlocking mechanisms are installed at the lowest landing door for accessing the hoistway, then access is enabled, but device complexity and potential safety risks increase

Engineering Contradiction:
ImproveAccess to hoistwayVSAvoidUnlocking mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The access function is extracted from the landing door system and relocated to the elevator car interior via the floor hatch assembly. This removes the need for complex manual unlocking mechanisms at the landing, simplifying the overall system while maintaining access capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The floor hatch assembly provides self-contained access control within the elevator car, using the car's own control systems and safety interlocks to manage access to the hoistway, eliminating the need for external unlocking mechanisms at the landing

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4686687A1Elevator car, elevator system and method of accessing a space in a hoistway of an elevator system
Publication Date: 2026.02.04 OTIS ELEVATOR CO
  • EP4686687A1 patent drawingFigure 1
  • EP4686687A1 patent drawingFigure 2A~2B
  • EP4686687A1 patent drawingFigure 2C~2D

AI summary

An elevator car (6) is configured for moving in a hoistway (4) between a plurality of landings (8a-8d). The elevator car (6) comprises a floor (6a) provided at a bottom of the elevator car (6) and at least one floor hatch assembly (22) formed in the floor (6a). The at least one floor hatch assembly (22) is movable between a closed configuration and an open configuration. When arranged in the open configuration, the at least one floor hatch assembly (22) provides an opening (60) in the floor (6a) of the elevator car (6) that allows a person (20) to access a space (24) in the hoistway (4) below the elevator car (6) from inside the elevator car (6). When the floor hatch assembly (22) is in the open configuration, the area of the opening (60) provided in the floor (6a) of the elevator car (6) covers an area of at least 0,35 m2.