Bistable Electromagnet Guardrail Lock for Ski Lifts

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Solution Overview

Problem

Existing ski lift seats lack adequate safety measures to prevent the guardrail from being raised during transit phases, leading to potential safety risks, and existing solutions are complex, heavy, and require significant maintenance, making them unsuitable for existing installations.

Innovation Solution

A ski lift seat with a bistable electromagnet and movable rod system that locks the guardrail in a lowered position, preventing accidental raising, and is designed to be lightweight, easy to maintain, and adaptable to existing installations, with a locking mechanism that uses a rocker and blocking member to secure the guardrail in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical locking devices are used to prevent guardrail raising during transit, then passenger safety is improved, but device complexity increases and maintenance requirements increase

Engineering Contradiction:
Improvepassenger safetyVSAvoidlocking device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical locking devices with a magnetic field-based locking mechanism. The magnetic member (electromagnet or permanent magnet) creates a magnetic field that interacts with the ferromagnetic material in the guardrail, providing reliable locking without complex mechanical linkages, springs, or actuators. This substitution maintains high reliability for preventing guardrail raising during transit while significantly reducing device complexity and maintenance requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the locking mechanism and the guardrail. Instead of direct mechanical contact and engagement, the magnetic field serves as the mediating force that locks the guardrail in the lowered position during transit and releases it at stations. This intermediary approach simplifies the overall system while maintaining effective locking functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If mechanical locking devices are used to lock the guardrail, then passenger safety is improved, but the vehicle weight increases leading to premature wear

Engineering Contradiction:
Improvepassenger safetyVSAvoidvehicle weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces heavy mechanical locking components (linkages, springs, actuators, locking pins) with a lightweight magnetic field-based system. The electromagnet or permanent magnet, along with the ferromagnetic material in the guardrail, creates sufficient locking force without the need for heavy mechanical structures. This substitution maintains reliable safety locking while significantly reducing vehicle weight, thereby preventing premature wear of the ski lift installation components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If traditional mechanical locking systems are used, then guardrail locking is achieved, but sensitivity to frost and climatic conditions increases

Engineering Contradiction:
Improvelocking functionVSAvoidfrost sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces frost-sensitive mechanical components (moving parts, springs, lubricants) with a magnetic field-based locking system. Magnetic fields are not affected by temperature, frost, or moisture, allowing the locking mechanism to operate reliably in harsh alpine conditions. The magnetic interaction between the magnet and ferromagnetic material remains consistent regardless of climatic conditions, eliminating the sensitivity issues inherent in traditional mechanical systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating principle from mechanical force transmission to magnetic field interaction. This parameter change fundamentally alters how the locking function is achieved, making it insensitive to temperature and frost. The magnetic field strength and ferromagnetic material properties remain stable across a wide temperature range, ensuring consistent locking performance in both cold and warm conditions.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively enhances passenger safety by preventing guardrail lifting during transit, is less complex and maintenance-intensive than existing systems, and is less sensitive to harsh climatic conditions, while being easily installable on existing seats without excessive weight addition.

Implementation Method 1

a bistable electromagnet provided with a movable rod between a first stable position in which the rod allows the guardrail to be locked in the lowered position

Methodology Applied
Scientific EffectElectromagnetism: Electromagnet

Data Source

PatentEP2864173B1Mechanical chairlift seat and installation equipped with this seat
Publication Date: 2016.05.18 SOMMITAL
  • EP2864173B1 patent drawingFigure 1
  • EP2864173B1 patent drawingFigure 2~3
  • EP2864173B1 patent drawingFigure 4~5

AI summary

This seat (1) comprises a guard-rail (10) able to occupy a lowered first extreme position and a raised second extreme position, and means for locking the guard rail (10) when it is in a lowered position. The locking means comprise a bistable electromagnet (12) provided with a rod (14) that is able to move between a stable first position in which the rod (14) allows the guard rail (10) to lock in the lowered position by interposing an obstacle in the upward path described by a guard rail element (17) to pass from the lowered position to the raised position, and a stable second position in which the rod (14) allows the guard rail (10) to unlock so that it can be moved into the raised position by moving the obstacle away from the upward path described by the guard rail element (17).