Retractable Elevator Stop for Low Overhead Clearance

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Solution Overview

Problem

Existing retractable stops for low overhead elevators face challenges in meeting the minimum clearance requirement due to their thick lateral profile, which is necessary for structural rigidity, and this can lead to the need for costly modifications to the counterweight or elevator system.

Innovation Solution

A retractable stop design featuring a cross member that pivots from a horizontal to a vertical position, allowing the impact plate to be at least substantially vertical when retracted, reducing the lateral profile and eliminating the horizontal vector of impact force, thus meeting the clearance requirement without additional cost or modifying the counterweight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the support member is constructed with sufficient lateral dimension and heft to provide structural rigidity, then the structural rigidity is improved, but the lateral profile increases and fails to meet the minimum clearance requirement

Engineering Contradiction:
Improvestructural rigidityVSAvoidlateral profile
Core Design Contradiction:
StrengthVSLength of stationary object

Solution Approach 1:

The support member is designed to be movable between a horizontal position (when engaged with the counterweight) and a vertical position (when disengaged). This dynamic repositioning allows the structure to achieve full lateral dimension when needed for strength, while retracting to meet clearance requirements when not in use.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stop assembly is divided into separate functional components: the support member for structural strength, the impact plate for force transmission, and the mounting channel for attachment. This segmentation allows each component to be optimized independently - the support member can be thick-walled for rigidity while the overall assembly retracts to meet clearance specifications.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the triangular configuration is used to block downward movement of the counterweight, then the stop function is improved, but the support member must bear horizontal vector of impact force requiring increased lateral dimension

Engineering Contradiction:
Improvestop functionVSAvoidlateral dimension of support member
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The horizontal force-bearing function is extracted from the support member and transferred to the impact plate. The impact plate is positioned to receive and absorb the horizontal impact force directly from the counterweight, while the support member focuses solely on providing vertical structural support and rigidity. This functional separation allows the support member to be thinner while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Length of stationary object

If the retractable stop is designed to meet minimum clearance requirement, then the clearance is improved, but the load bearing capacity in deployed position may be compromised

Engineering Contradiction:
ImproveclearanceVSAvoidload bearing capacity
Core Design Contradiction:
Length of stationary objectVSStrength

Solution Approach 1:

The support member transitions from a compact vertical configuration (retracted) to an extended horizontal configuration (deployed). In the retracted position, the minimal lateral profile meets clearance requirements. In the deployed position, the full horizontal extension provides the necessary structural span and load-bearing capacity to safely stop the counterweight.

Inventive Principle:
Principle #15Dynamics

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 improved lateral profile of the retractable stop allows for safe operation within the limited space of low overhead elevators, maintaining structural rigidity and load-bearing capacity while meeting the minimum clearance requirement without additional expense or modifying the existing counterweight.

Implementation Method 1

A retractable stop design featuring a cross member that pivots from a horizontal to a vertical position

Methodology Applied
Scientific EffectPivoting: Hinge

Implementation Method 2

the horizontal impact plate blocks the downward movement of the counterweight with the impact force transmitted into the pit floor through the mounting channel and support member

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2558393B1Retractable stop for low overhead elevators
Publication Date: 2021.09.08 OTIS ELEVATOR CO
  • EP2558393B1 patent drawingFigure 1~2
  • EP2558393B1 patent drawingFigure 3
  • EP2558393B1 patent drawingFigure 4

AI summary

A retractable stop (20) and the method of use thereof to control travel range of an elevator system are disclosed. The retractable stop (20) may include a vertical mounting bracket (21), an impact plate (30), and a support member (40). The support member (40) may include an upper end (41) pivotably connected to a distal portion (32) of the impact plate (30) and a lower end (42) movable in relation to the mounting bracket (21). The proximal portion (31) of the impact plate (30) may be pivotably connected to the mounting bracket (21). When the retractable stop is in a retracted position, the impact plate (30) does not significantly contribute to the lateral profile of the retractable stop.